ition Tet arket milk’ refers to fluid whole milk that is “S0ld tg v The ne a ally for direct consumption. It excludes milk con. individual arm and that used for the manufacture of dairy sumed on products be defined as the whole, fresh, clean, lactea, Note. Milk may btained by the complete milking of one or more secretion a h ahimals, excluding that obtained within 15 healthy mi te 5 days after calving or such periods as May days before to render the milk practically colostrum-free, be aera the minimum prescribed percentages of and a milk-solids-not-fat In India, the term ‘milk’, im unqualified, refers to cow or buffalo milk, or a com. bination of the two. (Also see 1.4.) 1,3 The Market Milk Industry in India and Abroad eginning in organized milk handling was made sar io cate of Military Dairy Farms (oldest: Allahabad, 1889), the salient features of the market milk industry s a n: 7 a tessa of milk in Co-operative Milk Unions (oldest: Allahabad, 1913) established all over the country on a small scale in the early stages. (ii) Long distance refrigerated rail-transport of milk from | Anand to Bombay since 1945. @ (iii) Pasteurization and bottling of milk on a large scale for organized distribution was started at Aarey (1950), Worli (1961), Caicutta (Haringhata, 1959), Delhi (1959), Madras (1963), etc. (iv) Establishment of Milk Plants under the Five-Year Plans for Dairy Development all over India, These were taken up with the dual object of increasing the national level of milk consurp- Scanned with CamScanner oMarket Milk 3 tion and ensuring better returns to the primary milk producer. Their main aim was to produce more, better and cheaper milk. The actual expenditure is given in Table 1.1. TABLE 1.1 Actual expenditure on the market milk industry in India’s Five-Year Plans Plan Period Expenditure 1 Five-Year Plan (1951-6) " -do- (1956-61) ML -do- (1961-6) Spill-over I to 111 (1966-7) Rs 25.7 crores —————_ e+ Source: Dairying in India by Khurody (1974). Rs 7.8 crores Rs 12.0 crores Rs 36.6 crores (b) The_present_status of the m: rket_milk industry. in this country may be gauged from the fc ing facts and figures: (i) Total annual milk production in India has been estimated at illion tonnes (1976) ae (ii) Although India possesses nearly one-fifth of the world’s bovine population (cow. buffalo and goat), milk production in India accounts for only about one-sixteenth of the world’s total of 428 million tonnes (1975). 7) 3 (iii) Due to the large human population, daily per capita milk consumption today (1975). works out to about 114g, while that recommended by the Medical Authorities is 280 g. (iv) The main reasons for this acute shortage of milk are low milk-yielding capacity of the average Indian cow and acute shortage of feeds and fodder. aan (vy) Lack of organized milk production and collection, restric- ted transport facilities (especially refrigerated) and shortage of processing and marketing organizations have greatly hampered the growth of the market milk industry. (vi) Poor-quality milk, widespread adulteration, and lack of quality consciousness among the great majority of consumers have further aggravated the situation. (c) Table 1.2 gives India’s position in relation to some of the important milk producing countries of the world: Scanned with CamScanner © scone wih one cameOutlines of Dairy Technology TABLE 1,2 josition in relation to milk producing countries iss of the world animals in «Milk yield "Total aay ania milking cow/ prow annum (hg) (1000; 00> tonney) 2200 2,900 4154 52,800 faut 3130 30413 2 B—450 21,360 India co157 W. Germany 39 3779 22,545 Poland 62 2361 14,860 UK. 53 3950 13,000 *Cows, buffaloes, goats and sheep. Source: F.4.0. Production Year Book, 1970, (a) The production of milk in India for selected years is given n Table 1.3, TABLE 1,3 Milk production in India —_;— Year production ____Million tonnesy 1951-2 1956-7 1961-2 1968.9 1973-4 1978-9 a 28.6 = (estimate) | Source: Dalrying in India, \DSA Publication, 1976, (2) The proportion 4 cow, butt: Me production in India is Table a Biven in Tabi : (1) The densi SHY Of milk 1 poatustl x for India is Biven in, Hee a ‘ (8) A summary Of milk in India (1966); is He sin Ate gO A mition oe Tal Boat milks to total milk Es daily milk production) Scanned with CamScanner (© scanned wt onENScnnerMarket Milk 5 TABLE 1.4 Species contribution to total milk production in India Total production Type of Milk = _ Per cent ‘Amt (1000 tonnes) Cow 36 8,400 JS Buffalo 63.6 15,900 Goat 28 681 Source: F.4.0. Production Year Book, 1974. TABLE 1.5 Density of milk production in India Category Per village State Per sq. km Min. kg Assam 21 kg Ave. 88 kg Indian Union 15.6 kg Max. 472 kg Delhi 98.0 kg ee ed ‘Note. District Amritsar 113.3 kg/sq. km Denmark 362.1 kg/sq. km Source: Report of the Marketing of Milk in the Indian Union (1961). TABLE 1.6 Summary of utilization of milk in India Percentage in relation to Items Total milk Total quantity converted production into milk products Fluid milk 445 = Manufactured milk 55.8 (100) Ghee 2. BI Dahi 7.8 M0 Butter 6.3 na Khoa 49 8k lee cream 0.7 1a Cream 1 M4 Other products 12 22 (Mainly chhana) > Sounce: Indian Dairyman (1976), 28 (11), 512. Scanned with CamScanner (© scanned wt onENScnner6 Outlines of Dairy Technology (h) The daily per capita consumption of milk in some Of the major developed dairying countries (1970) is given in Table 17 and that in developing countries in Table 1:8, » TABLE 1.7 Daily per capita mitk consumption in some developed countries of the world (1979) ene ee — Estimated daily per Estimated daily per” Country capita consumptionin Country capita consumption iy, terms of liquid milk (a) terms of liquid milk (yi UK. 1315 France 1335 ~ Australia 14g W. Germany 1301 New Zealand 2032 Netherlands nn Canada ss Norway 2046 USA. 1003 Sweden 1812 Denmark 1188 Switzerland 1583 Finland 2165 Miscellancous. TABLE 1.3 Daily per capita milk consumption in some developing — countries of the world (1975) —-~ Estimated daily per capita Estimated daily per Country Consumption in terms of Country _ capita consumplign in liquid mitk (y) terms of liquid milk (g) oor = Bangladesh SI Isract 317 India 14 Japan* 122 Iran 172 Pakistan 25 Iraq 170 Philippines 2 lered a developed country, Source; Tudian Dairyman, 29 (3), 150 (1977). Note. The market milk industry in the advanced dairying coun- tries of the world has now reached -a high level in sanitary Production, transportation, Processing and distribution. These improved conditions are a result of the passage of dairy and milk-control ordinances in nearly all major cities, and of control laws in states where dairying is limportaa Credit should also be given to many producers, Se and manufacturers of dairy equipment for setting hig standards, Scanned with CamScanner (© scanned wt onENScnnerOutlines of Dairy Technology 10 sywaNyNsuoD AWA VT “Bt “p6l) Bury hq AusspwayD duing fo 4o0g-1xaL Y 3400S wuaiotg — (9 *x2\dwoo g) * *soukzug sumtin sasea Pantossict squaWistd \ Eh tana orn AI . \ auoidad (urungjeseq-») — (uriNqo{8o19e7-g) (4 ‘¢ *2) : =as0po4d uynqo[so19e | uUNgIe}Ie] ulase> I mT j “919 *] tng ‘ag Jo sees “BW ‘ED “EN “WJO CaA‘a ‘d ‘v) (urq3s9p) sopuojys‘sarenio — uliorg ura10d-uoN, SUWENA Duarosw> joJ21S9}04 —_spidijoydsoud \ “sayeydsoyd i | Ll IL i ] | | | pecans squoninsuoa sonewt sooueisqns — (Je8ns 411) sooueysqns I 33y1O yesoutyw snoua8osIN aso1ey pareisossy veg ony \ ! - J i i | (ANS) re HOW-spHIOs (mia wea a! (SL) SP Hos [10L SDA ____ | nN Scanned with CamScanner © scone wih one cameMarket Milk u (ii) The average chemical composition of milk of a few breeds of Indian cows and the Murrah buffalo is given in Table 1.11. TARLE I It Chemical composition of milk of Indian breeds Percentage composition — on Lactose Ash _—_—————_ cow/buffalo sindt 86.07 4.90 3.42 491 0.70 Gir 26.44 4.73 3.32 4.85 0.66 Tharparkar 86.58 4.55 3.36 4.83 0.68 Sahiwal 86.42 4.85 3.33 5.04 066 Murrah 83.63 6.56 3.88 5.23 0.70 Source: [DRI Annual Report (1948). Note. See Appendix II for more information on the composition of buffalo milk. (iii) The average chemical composition of milk of some foreign breeds of cows is given in Table 1.12. ‘TABLE 1.12 Chemical composition of milk of foreign breeds of cow Percentage composition Breed —— Water Fat Protein Lactose Ash Holstein 87.74 3.40 3.22 4.87 0.68 Shorthorn 87.19 3.94 3.32 4.99 0.70 Ayrshire 87.10 4.00 358 4.67 0.68 Brown Swiss 86.59 4.01 3.61 S04 0.73 Guernsey 85.39 4.95 391 4.93 0.74 Jersey 85,09 5.37 392 4,93 071 a Source: The Fluld-Milk Industry by Henderson (1971). Scanned with CamScanner (© scanned wt onENScnner12 Outlines of Dairy Technology (iv) The detailed composition of milk is given in Table 1.13. ( TABLE 1.13 : Detailed composition of milk Approx. concentration (Weight per litre Constituents or group of constituents Br milk) 5 860 to 880 g Water sigma . F Lipids in Emulsion Phase. meres, 6 ale He ‘Milk fat (@ mixture of mixed triglycerides) Phasphellelas decithins, cephalins, sphingomyelins, 30% etc. 0.10 Sterols : Carotenoids Vitamins A, D, E and K Proteins in Colloidal Dispersion sg =Easein («, B, y fractions) et B-lactoglobulin(s) a g a-lactalbumin i ‘Albumin, pseudoglobulin, etc. Enzymes (catalase, peroxidase, phosphatases, amylases, lipases, proteases, etc.) Dissolved materials Carbohydrates Lactose (a and p) 45to 508 Glucose 50 mg Inorganic and Organic ons and Salts Calcium* 1.25 g¢ Phosphate (as PO,) 2.10 Citrates* (as citric acid) 2.00 g Chloride 1.008 Sodium, potassium, magnesium, etc. Water-soluble Vitamins Thiamine, riboflavin, niacin, pyridoxine, panto- thenic acid, biotin, folic acid, vitamin Bys, etc. Ascorbic acid . Nitrogenous Materials (not Proteins ot Vitamins) Ammonia, amino-acids, urea, creatine or creati- nine, uric acid, etc. Gases (milk exposed t0 air) Carbon dioxide, oxygen, nitrogen, ets. Trace Elements Those usually present are copper, iron, etc, *Partly in colloidal dispersion. Sounce: Principles of Dairy Chemistry by Jenness and Patton (1969). Scanned with CamScanner © scone wih one cameCOMPOSITION AND NUTRITIVE VALUE Lye Milk is a complex mixture of lipids, carbohydrates, proteins and many other organic compounds and inorganic salts dissolved or dispersed in water. The most variable component of milk is fat followed by protein. Co The composition of milk varies with the species, breed, diet, lactational period and interval between milking, There is individual variation also. Fat Buffalo's milk contains 6.5 per cent fat. Cow's milk contains 4.1 per cent fat. Milk fat or butter fat is of great economical and nutritive value. The flavour of milk is due to milk fat. Milk is a true emulsion of oil-in-water. The fat globules are stabilised by a surrounding membrane composed of proteins, phospholipids and cholesterol. Fat globules are visible under a microscope. Each globule of fat is surrounded by a thin layer which is composed of a lipid-protein complex and a small amount of carbohydrate, The lipid portion includes both phospholipids and triglycerides. Fat globules vary widely in size from 2 to 10 um (micro metres) and in number 3x10° per ml. The larger fat granules come to the surface of milk more quickly due to low specific gravity and this can be observed in the transportation of milk. The structure of fat globule is shown in Fig. 5-a Milk fat is a mixture of several different glycerides, They contain about 64 per cent fatty acids ranging from 4 to 26 carbon atoms. Milk contains considerable amount of short chain fatty acids which give the characteristic flavour and off flavour, Due to their low melting point -10 to 12°C, they give Soft solid consistency to butter. Saturated fatty acids account for butyric and caproic acid 62 per cent and unsaturated 37 per cent, Of the uns: d fatty acids, 3.8 per cent constitute polyunsaturated fatty acids. Other lipid materials present in milk are phospholipids, sterols, free fatty acids, carotenoids 4nd fat-soluble vitamins, Carotenes are responsible for the yellow colour of milk fat. Gerber test is Used to know the percentage of fat present in food. 105 Scanned with CamScanner © scanned wth onEN Scannerr a 5 . ily. Milk, butter and cream should Milk fat absorbs volatile odour very readily, MOL be crag strong odours. Proteins ficogea fa walle. Is pred Casein: Casein constitutes 80 per cent of the total nitrogen in milk. It is precipitated onthe ayy, ining whey protein constitutes lact 7 cation of milk to pH 4.6 at 20°C, The remaining wl ey iene tli lactalbumin. Milk protein contains proteoses, peptones an ; Phospholipid Trilayer Figure S-a: Structure of fat globule membrane in milk. Milk fat is composed mainly of tiacylglycerols which are present as an emulsion in which the fl lobules are stabilised by a surounding membrane composed of proteins, phospholipids and choles terol. The fat globules also contain small amounts of cholesteryl esters apa fat-soluble vitamins a4 | provitamins mainly A, D and B-carotene, 1 Casein is classified as a phosphoprotein because of the phosphorie aci i i its | " ric acid ined in molecular structure. At the normal acidity of fresh milk (about rH 6.6). ease ieee canbe | through the phosphoric acid part ofits structure with caleium easeras ae Hence, casein occurs in milk | as a colloidal protein calcium Phosphate complex, . | Casein is also a glycoprotein, Glutamic acid is the predominant one in casein, Proline, aspartic: leucine, lysine and valine are also present, Casein is a 800d sour it . a nce of esser it i sein contains 8.2 per cent caleium and 5.7 per cent earbohydrures, ean eo acts vou ci also be separated from milk by the addition of rennin, an enzyme secreted by the Whey proteins: Whey proteins are male up of a-lactabunin and i the immunoglobulins, enzymes and proteose—peptones, ealab imal for ab sues feat tal whey protein, These are not precipi by acid or rennin, ty eo er Seo, by heat. Whey also contains small amounts of lactofertin und serum transferr By a process involving ultrafiltration, whey protein concentrate is produced. Whey protein isolates are also produced, It can be given in lactose intolerance. Scanned with CamScanner (© scanned wt onENScnnerFr carbohydrate contains 4-5 per cent carbohydrate. The chief carboh: ride, although trace amounts of glucose, galactose and other sugars are also present. L. oe pydrolysis glucose and galactose. Lactose has only one sixth the Sweetness of sucre on hy an at fase and one third-one fourth of its solubility in water, When milk is heated, lactose reacts with protein and develops a brown colour. The development of brown colour is due to nonenzymatic browning, It called Maillard reaction. ‘The acid fermentation is used in making butter, cheese and curd ydrate present in milk is lactose, a disac- actose gives Minerals Chlorides, phosphates, citrates, sulphates and bicarbonates of sodium, potassium, caleium and magne- sium are present. These salts influence the condition and stability of the proteins, especially the casein fraction. Copper and iron are important in the development of off flavours in milk and milk products, In addition to this, milk contains trace elements like zine, aluminium, molybdenum and iodine. Enzymes The enzymes found in milk can originate from the mammary glands or may be released by contami- nating bacteria. Alkaline phosphatase exists as lipoprotein and is distributed between the lipid and aqueous phases. This enzyme is inactivated hy normal pasteurisation procedures and its activity is tested to determine the effectiveness of pasteurisation. More than one type of lipase occur in milk. Milk lipase is responsible for the development of rancid Navours in milk. Bacterial is very resistant to heat and ean cause serious quality defects. Lipases may be important in the development of desirable flavours in some cheeses. Xanthin oxidase occurs in the fat globule membrane. It is a conjugated protein complexed with FAD, iron and molybdenum. The enzyme d IN and riboflavin. The nboflavin content of milk may thus be due to xanthin oxidase. Xanthine oxidase can catalyse the oxidation of aldehydes which are some of the aroma constituents in fermented dairy products. The enzyme is not destroyed by pasteurisation. Colour White colour of milk is caused by the reflection of light by the colloidally-dispersed casein, calcium and phosphorus. Yellowish colour of milk is due to the presence of carotene and riboflavin, Fat-soluble Ssrotenes are found in milk fat; riboflavin is water soluble which can be visible clearly in whey water. Flavour and aroma jour sensation in mouth is due to fat protein a ily sweet because of its lactose content, Fla i oat poi Dumber af ne Salts such as calcium phosphate. The slight aroma of fresh milk is pentane by short dal 'ow molecular weight compounds stich as acetone, acetaldehyde, dimethy pale 7 Portion af {MttY acids. Some of the volatile compounds to the Navour of milk are unique to the (3 Oe nilk: Boiling changes the favour of fresh milk more than pasteuisation, Sceonte a flavour can result from the oxidation of phospholipids in the milk. Since em PS of tha, evelopment of oxidised favour, copper containing equipment isnot wd in de OF Oxygen gy Unsaturated fatty acids are particularly susceptible 10 autooyitation it nd Unpleasant flavour substances are produced. > Scanned with CamScanner (© scanned wt onENScnnerOff Mavour in milk may be influenced by the health of the cow or the feeds that are by the cow, action of bacteria, chemical changes in milk, or the absorption of foreign nao the milk is drawn, YOU at Off Mavours are also produced when milk is exposed to light. In this reaction, ryptophy riboflavin may be involved and their content decreases when the off-flavour develops. “J Anything that alters the membrane and permits contact of the lipases with the fat wil} Promote raneidity and off flavour. NUTRITIVE VALUE Table 5.1 gives the nutritive value of milk and milk products. Milk hay good quality protein and the biological value is over 90. Though milk contains only 34 per cent protein, due to the quality of protein and the amount that can be ingested and the presence of other nutrients makes it indispensable. Lysine is one of the essential amino acids which is abundant in milk proteins. Cheese, khoya and dehydrated milk powders are concentrated forms hence contain high amount of nutrients per unit. Milk is the only substance that contains lactose, which has galactose which is essential for te synthesis of myelin sheath, Lactose, not being easily soluble favours the growth of lactic acid baci ie the intestine, which decreases the pH. This drop in pH favour calcium absorption. Lactose also increases the permeability of the small intestine for calcium ions. Milk sugar due to its controlled glycaemic effect. is preferred as a source of carbohydrate. Nutrient content of Aavin Toned* milk (100 ml) Energy kcal 63 Carbohydrate g 46 Protein g 32 Fat g 3.0 Calcium mg 125 Sodium mg 50 Magnesium mg 10 Potassium mg 150 Phosphates mg 210 Citrate mg 200 Chloride mg 100 Bicarbonate mg 20 Sulphate mg 10 Vitamin A IU 200 + Aavin toned milk contains skim milk powder, cow's milk and buffaloe’s milk, Source The Tamil Nadu Co-operative Milk Produc- ers’ Federation Lid Se Ee Scanned with CamScanner (© scanned wt onENScnnerPhysico-Chemical Properties of Milk Constituents A. Major Milk Constituents (a) Warer. Constitutes the medium in which the other milk constituents are either dissolved or suspended. Most of it is ‘free’, and only a very small portion is in the ‘bound’ form, being firmly boand by milk proteins, phospholipids, etc. (b) Mitk fat (lipid). The bulk of the fat in milk exists in the Scanned with CamScanner (© scanned wt onENScnnerMarket Milk 17 form of small globules, which average approximately 2 to 5 microns in size (range 0.1 to 22 microns). This is an oil-in-water type emulsion, The surface of these fat globules is coated with an adsorbed layer of material commonly known as the fat globule. membrane. This membrane contains phospholipids and proteins in the form of a complex, and stabilizes the fat emulsion. In other words, the membrane prevents the fat globules from coalescing but keeps separated from one another, The emulsion may, however, be broken by agitation (at low temperatures), heating, freezing, etc. When milk is held undisturbed, the fat globules tend to rise to the surface to form a cream layer. The thickest cream layer is secured from milks which have a higher fat content and relatively large fat globules (such as buffalo’s milk when compared with cow’s milk). Chemically, milk fat is composed of a number of glyceride-esters of fatty acids; on hydrolysis, milk fat furnishes a mixture of fatty acids and glycerol. (That milk fat is a mixture of true fats is established from the fact that it has no sharp melting point.) The fatty acids are saturated or unsaturated. Saturated fatty acids are relatively stable, On the other hand, the unsaturated ones play an important role in the physico-chemical properties of milk fat. () Milk proteins. Proteins are among the most complex of organic substances. They are vital for living organisms as they constitute an indispensable part of the individual body cell. Proteins are composed of a large number of amino-acids, some ‘essential’ and others ‘non-essential’. The essential amino-acids are necessary in the diet for the formation of body proteins. On hydrolysis, proteins furnish a mixture of amino-acids. The proteins of milk consist mainly of casein, B-lactoglobulin, a-lactalbumin, etc, Casein exists only in milk and is found in the form of a calcium caseinate-phosphate complex. It is present in the colloidal state. It forms more than 8 per cent of the total protein in milk. It may be precipitated by acid, rennet, alcohol, heat and con- centration, Casein itself is composed of a, 8, y fractions. The heterogeneous nature of a-casein can be observed through electro- phoresis. a-casein is the component in casein micelle that is responsible for the stabilization of the micelle in milk, Later studies have also revealed that a-casein is composed of at least two sub-fractions, viz., a,-casein precipitable by calcium-ion under Scanned with CamScanner © scanned wt oHEN Sconesiry Technology , tcalcium-S nsitive casein’; and calciut sein’, NOt precipitable st rel sitory of carbohy- ns. It js also the site for outlines Of Da' other © ‘ wn as whey or min are also know ne eset in the colloidal state and ns. syuble bY HEB. ints only in milk. It is in rystallization from water, “sixth as sweet aS sucrose, the defect crystals. t i i yen rc in conditions, for ened condensed milk, h of glucose B, both of ide. It is ferment- to yield | “acid and other organic acids and is important bo! h in the production of cultured milk products and in the spoilage of milk and milk products bY souring. © Mineral matter The mineral matter or salts of milk, although present in si ties, exert con iderable influence on the physico-chemical and nutritive value of milk. The major salt constitut . those present in appreciable quantities, include potassium, sodium, magnesium, calcium, phos- phate, citrate, chloride, sulphate and bicarbonate; the trace ele- . The mineral ments include all other minerals and sal salts of milk are usually determined after ashing. Although milk is acidic, ash is distinctly basic. Part of the mineral salts occur ID true solution, while a part are in the colloidal state. or ash. mall quanti 1 properties B, Minor Milk Constituents ilk, there are three types of ph “(@) Phospholipids. In mi La et eephatin and sphingomylin. Lecithin, which Ln er ictus ot) of the fat globule membraney products Itis i richness of flavour of milk and other dairy ees tie sensitive to oxidative changes, giving rise to agents, and no ait Phospholipids are excellent emulsifying SN chetétert, ‘This sPpa stabilize the milk fat emulsion. the fat, as . is appears to be present in true solution 1 , as part of the fat globule membrane complex and in _d Scanned with CamScanner os pho- © scone wine scarMarket Milk 19 non-fat portion of milk. complex formation with proteiz in the and (c) Pigments. These are: (i) fat soluble, such as carotene xanthophyll, and (ji) water soluble, such as riboflavin. Carotene is the colouring matter of all green leaves, where it is masked by chlorophyll. Carotene (the pure substance of which has a reddish- brown colour) is fat soluble and responsible for the yellow colour of milk, cream, butter, ghee and other fat-rich dairy products. Besides contributing to the colour of cow milk, carotene acts as an anti-oxidant and also as a precursor of vitamin A. One mole- cule of f-carotene yields two molecules of vitamin A, while a- carotene yields only one. Dairy animals differ in their capacity to transfer carotene from feeds to milk fat; this varics with species, breed and individuality. Cows in general, and some breeds in particular (such as Guernsey and Jersey), can transfer more carotene frone their feed to the milk fat than buffaloes, who do not seem to possess this capacity. Hence buffalo milk is white in colour. (The carotinoid content of buffalo milk varies from 0.25 to 0.48/ug/g, while that of cow milk may be as high as 30/ug/g.) Riboflavin, besides being a vitamin, is a greenish-yellow pig- ment which gives the characteristic colour to whey. (Earlier, the terms ‘lactochrome’ and ‘lactoflavin’ were used instead of ribo- flavin.) (a) Enzymes. ‘These are ‘biological catalysts’ which can hasten or retard chemical changes without themselves participating in the reactions, The enzymes are protein-like, specific in their actions, and inactivated by heat; each exzyme has its own in- activation temperature. The important milk enzymes and their specific actions are as follows: (i) Analase (diastase)—starch split- ting; (ii) Lipase—fat splitting, leading to rancid flavour; (iii) Phos- phate—capable of splitting ceriain phosphoric acid esters (basis of pliosphatase test forchecking pasteurization efficiency); (iv) Pro- tease—protein splitting; (Vv) Peroxidase and Catalase—decomposes hydrogen peroxide. (c) Vitamins. Although present in foods in very minute quanti- ties, these are vital for the health and growth of living organisms. As of today, over 25 vitamins have been reported. Those found in milk are: fat-soluble vitamins A, D, E and K; and water-soluble Vitamins of the ‘B Complex’ group (such as thiamine or Bi, ribo- flavin or Bz, pantothenic acid, niacin, pyridoxine or Bs. biotin. Scanned with CamScanner (© scanned wt onENScnner20 Outlines of Dairy Technology Biz, folic acid, ete.) and vitamin C (ascorbic acid). Absence 7 Vitamins in the diet over prolonged periods causes ‘deficiency diseases’. Scanned with CamScanner (© scanned wt onENScnner¥ Physical Properties of Mili protewn omplex biological fluid consisting of seven main components water far lactose), minerals, vita mins and enzymes It's a white coaane “ii tas an emulsion, protein and some mineral matters i coiled i lactose together with some minerals and soluble 9 teins int s due to its content of suspended particles of fat, proteins and ¢ e content o! tat Mitk pas a alour varies from white to yellow depending on the carotene content of " pleasant, slightly sweet taste, and pleasant odour It an excell ohesphates and nibatiavin Scanned with CamScanner © scanned wth onEN ScannerColor and optical properties catering by fat globules and casein mica Milk appears turbid and opaque owing, t0 WREST ot ight by the molecule, Wes sr of 5 Optical properties are influenced by the MANNE” AL magnitude of the particle. 1, ight mal r scattering occurs when the wavelength of ight matches WE TNITE S| th ths an smaller particles scatter light of shorter paar wavelengths of visible light (biye) slightly blue because casein micelles scatter the sl or of vitamin A, IS Fesponsity more than the red. Beta-carotene, the carotenoid precurs Ie for the creamy colour of cow milk, Flavour of milk fi its components. The natural sweet flavour of milk is due to the combined ctreccoin ne pen = flavours are very quickly developed in milk owing to several Taclor: Ted by animals may lead tq some undesirable flavours. Bacterial Bro malty or acid flavours. Specific gravity and density Milk is heavier than water. The specific gravity of cow milk varies from 1.018 to 1.036 ang oj buffalo milk from 1.018 to 1.038. Though specific gravity varies with temperature, (lower at higher temperature and vice versa), the rate of this variation is not uniform. The density of milk varies within the range of 1.027 to 1.033 ke/cm3 at 20°C. The density of milk is used to estimate the solids content, to convert volume into mass and vice versa ang ath in milk CAUSES fruity, byny to calculate other physical properties such as dynamic viscosity Viscosity Viscosity of milk depends on the temperature and the mount and state of dispersion of the solid constituents, mainly casein and fat. Viscosity of the whole milk at 25°C is about 20 Cooler temperatures increase viscosity due to the increased voluminosity of case whereas temperatures above 65°C increase viscosity due to the: denaturation of whey proteins, An increase or decrease in pH of milk also causes an increase in casein micelle voluminosity. . Surface tension The surface activity of milk is related to proteins, fat, phospholipids and fresh fatty ac present in it. Homogenization and heat sterilization increase the surface tension of m'* Milk has a surface tension of 50 dyne/em at 20° Freezing and boiling points of milk the freezing points of cow and buffalo milk vary from -0.12 to -0.5728C and from 05" 0.975% respectively. Freezing point of milk is mainly used t Sninead et boiling point of milk is 100.179C © determine added wa Acidity and pit Freshly drawn milk has a pH value ii the range of 6.5 $ '06./ and contains 0:14 te 9? Scanned with CamScanner (© scanned wt onENScnnertitratable acid calculated as lactic acid. There is no developed acidity in freshly drawn milk, the slightly lower than the neutral pH being attributed to the presence of carbon dioxide, citrate, casein ete. Heat stability of milk Heat stability is defined as the length of time required to induce coagulation at a given temperature or the temperature required to induce coagulation in a given time. The stability of milk system at the high processing temperatures to which milk is exposed for the manufacture of certain products is very important. Caseins and salt balance of milk governs its heat stability. Added citrates, phosphates and calcium have a great impact on the heat stability.) Y Clarification 4 Separation and clarification can be done at the same time in one centrifuge. Particles, which are denser than the continuous milk phase, are thrown back to the perimeter. The solids that collect in the centrifuge consist of dirt, epithelial cells, leucocytes, corpuscles, bacteria sediment and sludge. The amount of solids that collect will vary; however, it must be removed from the centrifuge. More modern centrifuges are self-cleaning allowing a continuous separation/clarification process. This type of centrifuge consists of a specially constructed bow! with peripheral discharge slots. These slots are kept closed under pressure. With a momentary release of pressure, for about 0.15 s, the contents of sediment space are evacuated. This can mean anywhere from 8 to 25 Lare ejected at intervals of 60 min. For one dairy, self-cleaning translated to a loss of 50 L/hr of milk. The following image is a schematic of both a clarifier and a separator. ‘aration, &y Scanned with CamScanner (© scanned wt onENScnnerJakieuet al composition of milk meant for ization of the chemic: Many dairy processes require standardization of vk might cequire contol of 3 iin market purpose or milk products manufacture, Standardizi CE alieoar tore only one component (usually fat) while allowing the others to vary components simultaneously. Standardization minated it may be defined as the adjustment of ane or more of the milk constituents to a it evel. In market milk industry, this normally involves reducing the butterfat content by addition of skim milk or through the removal of cream Objectives * To comply with the legal requirements for particular milk/dairy products. To provide the consumer with a uniform product To ensure economics in production. Addition of skim milk increases the volume of milk available for sale and removal of cream allows the production of other value added dairy products such as table cream, butter or other high fat products. Methods of Calculation For standardization of milk or cream for product manufacture, usually the proportions of the various ingredients of known compos can be done by n to be mixed, is required to be estimated Th: » Pearson's Square method aor Pearson's square method Draw a square and place in the centre of it the desired! at percentage. Place at the left h corners of the square, the fat percentage of the materis 7 number in the centre from the larger numbe: the remainder at the diagonally opposite rig side now represents the number of parts of each of the blended to have the desired fat content in res Corner refers to the parts of material whose the number at als to be mixed. Next, subtract th Tat the left hand side of the squa: ht hand corn and place ners. The number on the right h Original materials that must 5 ultant mix. The number fat test was to the at the upper rig! Placed at the upper left corre" the lower right corner relers art Parts Of mater whose tat tesi wt Scanned with CamScanner (© scanned wt onENScnnerplaced at the lower left corner. If the numbers on the right are added, the sum obtained will represent the parts of the finished product. , SA homogenization The process of making a stable emulsion of milkfat and milk serum by mechanical tment and rendering the mixture homogeneous is homogenization. This is achieved by passing warm milk or cream through a small aperture under high pressure and velocity, High-pressure homogenizers, low-pressure rotary-type homogenizers, and sonic vibrators, are used for the purpose. Milk and cream have fat globules that vary from 0.1 to 20 jum in diameter, The fat globules have a tendency to gather into clumps and rise due to their lower density than skim milk. When milk is homogenized, the average size of the globule will be about 2 jum. The decrease in the size of the fat globules increases their number and surface area. The newly formed fat droplets arc no longer coated with the original membrane material. Instead, they are covered with an adsorbed layer of plasma proteins, including casein micelles, micellar subunits, and remnants of membrane material. This brings about the stabilization of the milk emulsion and thus prevents the rising of the cream Homogenized milk has a creamier structure, bland flavour, and a whiter appearance. It has greater whitening power when added to coffee and tea than the same milk not homogenized. A soft curd is formed when homogenized milk is coagulated, which is mare easily digested than curd obtained from unhomogenized milk. In the manufacture of evaporated milk and icecream, homogenization reduces the chance of separation of fat resulting in a smoother texture of the finished product. However, fat cannot be separated from homogenized milk efficiently. Also, homogenization accelerates the action of lipase. Therefore, if homogenization has been carried out before pasteurization, the latter operation has to be carried out quickly with homogenized milk, to prevent the rancid flavour that could develop. Besides, the homogenization of milk after preheating to about pasteurization temperature is advisable from the microbiological point of view. Such a combination causes inactivation of natural milk lipase due to heating and thus avoids the possible lipolysis due to increased surface area of fat globules in homogenized milk. Scanned with CamScanner (© scanned wt onENScnnerAoxsribution of Milk gh the highly is distributed throug! Currently around 80% of the total milk prada is te ars, retalrs, fragmented unorganized sector, which includes 10 Le pdr tia and the producers themselves. On the other hand, the org the remaining 20% of the total milk produced. , oducts. In light « India currently represents the world’s biggest market for milk ane mike mucs He its growing population, higher incomes and growing health consci aaeaeat milk is steadily increasing in the country. According to IMARC Group -enort tie “Dairy Industry in India: Market. , Growth, Prices, Segments, Coopera' ; he rua Dairies, Procurement and Distribution”, the total production and consump ion of d during 2014-15 reached 147 Million Metric Tons and 138 Million Metric Tons, resp) Some factors which help in deciding the mode of distribution of milk are as follows: 1. Keeping quality and kind of milk. 2. Perishable nature of milk and its products. 3. Possible contamination. 4. Proper supervision and control in distribution. 5. Cost of distribution/delivery of milk. Distribution of Raw Milk: In places of temperate climate and in sub-temperate conditions raw milk is distributed directly to consumers. This cannot be recommended in area other than temperate regions Where the milk production is carefully supervised and a short period lapses between production and consumption, the raw milk may be distributed provided the temperature milk does not go beyond 10°C at delivery, Raw milk consumption may probably co. rural area but strict hygienic control is required to see that milk is of good quality Distribution of Pasteurized Milk: tinue ir The deterioration in quality of pasteurized milk is mainly due to post pasteurization contamination, cted i : 1. Buildings density in particular locality OMS Deaina eer 2. Topography of the area 2. Number of customers 4. Distance of the area from dairy plant Temperature af milk at delivery 6. Type of deliv 7, Shop di vehicles, ution vs. home delivery Containers of milk Distribution: 1 Dispensing in sealed cans, 2, Dispensing in bottle Scanned with CamScanner (© scanned wt onENScnner3. Distribution by polythene bags oF tetra pack System of Distribution of Milk: Sound system of milk distribution is essential for: (a) Efficient, well organized retail marketing of milk. (b) Simple, convenient for both farmer and customers. Systems: There are three types: (i) Cash And Carry System: The customers are required to pay the cost of milk to vendors at the time of delivery of milk Merits: 1, Maintenance of account of sale proceeds of milk is easy 2. Commission of vendors can be calculated easily and promptly. Demerits: 1. Handling of huge amount of coins and currency is a problem 2. Daily counting of money is cumbersome. (ii) Coupon System: {mn this system a set of coupons is issued to the customers on advance payment. Customers receive milk in exchange of coupons and purchase new booklet of coupans when they run short of it on advance payment Meri 1. Chances of loss of money are eliminated, 2. Money on dairy farm is received much in advance which can be profitably utilized. Demerits: 1. Value of unredeemed coupons cannot be ascertained easily. 2. Account of sale proceeds of milk at the close of calendar month cannot be as clear as of cash and carry system. (iii) Card System: Milk cards are printed and sold to customers on advance payment. Validity of milk cards is limited to a month. Date of issue is not fixed but expiry of all sold cards is tixed. Customers who could not take milk for a day or days together are liable to get the cost of milk refunded, immediately after supply of milk is made, the quantity of milk is noted at the back of the card on each date. Card can be issued from the office of the Dairy Officer. One day time is aliowed for customer to register, At the time of issue of card timings of milk delivery are notified, Usually yellow cards are issued for cow's milk and blue cards for buffalo milk Merits: 1 Cost of milk is received in advance which can be utilized advantageously 7. |rouble of daily counting of maney/coupons eliminated demerits —_ Scanned with CamScanner © scanned wth onEN Scannerer e to both customers and |y of milk causes great inconvenience (0 -supp! 1, Refund for non ganisation vwsiiese d printing and issue of milk cards and refund Inte gone 5, Customers have to pick up milk only from as: od deal of labour and time. int Daler: milk vendin, ‘ni dosetd er etal. NDDB designed coin (Token oe ve naing machine, popularly known as “Push Mini Dairy”. The mi Te recess tse machines varies from 1,000 to 1,300 litres each The consumer : ‘own container large enough to hold the milk required by him/her. His of milk Milk is a white liquid produced by the mammary glands of mammals. All meine Inu humans will normally produce milk to feed their offspring uintil they are ready for solic foo There are different types of milk available in the market, some common and well-known and some less known. Cow's mik is one which is the most common type of milk and is well known in both urban and rural areas Different Types of Milk Available In India 1. Toned Milk Toned milk is actually a process from which the fat is removed only once | Photo Courtesy Of: Wikimedia Commons Toned milk is actually a process from which the fat is removed onh once. It is a mixture of skim powder milk and water which are added to buffalo’s milk to decrease the fat. . 2. Double Toned Milk Double toned milk is the freshest forms of milk one can ever have. Double toned milk is Prepared by 2 mixture of cow or buffalo milk or both with fresh skimmed milk. Or it cain also be obtained by a mixture of cow or buffalo milk or both that has been standardized to fat and solids-not-for-percentage. 3. Standardized Milk Standardized refers to milk that comes from cows, buffalos, goats or sheep or a combinatio of any of these that has been standardized to lat and solids-not-fat percentage. 4. Full Cream Milk Full cream milk means a combination of buffalo or cow milk or a both that has been standardised to fat and solids-not-fat-perce: be pasteurized and should shaw a negative phor Product by a combination ‘ntage. Full cream milk shoul Dhates test 1 should he stored in clean 1 sanitary containers that are properly sealed so as to prevent contamination aminatig Scanned with CamScanner (© scanned wt onENScnner5. Skimmed Milk Skimmed Milk is obtained by after skimming, that is removing cream from the milk. As cream has been removed from milk, it will contain 0.3% of fat. Itis also known as non-fat milk. The main benefit of skimmed milk is that it helpsiin reducing weight) 6. Cow Milk No matter where you go cow milk is the most common type of milk which is the primary animal milk consumed by humans. Cow milk helps in losing weight, building strong bones, teeth and also boost the immune system. It helps in reducing fat, protects the heart and prevents diabetes also. 7. Buffalo Milk itis high in fat, almost twice as high as that of cows milk. Duc to this, itis very hard to digest especially for infants. It is higher in saturated fat and overall calories as well. 8. Goat Milk Goat milk has a similar composition to cow milk. It could be a healthier replacement, lowering fat and rich in protein and calcium. It is easy on digestion and is also known to reduce inammation, 9. Sheep Milk Sheep milk is another kind of animal produced milk which is a good source of protein and calcium but also rich in total fat and calories. The solid content of sheep milk makes it particularly appropriate for cheese and yoghurt making. 10. Camel Milk —— Camel milk is slightly saltier in taste and is high idvitamin cls highly used as an alternative to cow's milk in UAE. Ithas a similar composition to cow milk and could be a better option in terms of high protein, Camel milk is usually consumed raw or fermented. It is lactose- free and a good alternative for those who are lactose intolerant. 11, Soy Milk Soy milk is extracted from soybeans. It is a popular dairy alternative for vegans and people , who are lactose intolerant. Since it comes from plants, it is naturally free of cholesterol, low 'n saturated fat and contains absolutely no lactose. It contains an equal amount of protein which is there in cow's milk. 12. Almond Milk popular drink which is recommended to a person on a dict. Almond milk neither contains cholesterol nor lactose. It is also an jdeal alternative for those who are lactose intolerant or jave aliergies with) soy. The milk 1s a Lasty, dairy-tree, say free and lactose-free alternative Scanned with CamScanner © scanned wth onEN Scanner13. Coconut Milk Jactose-free and Coconut milk is a popular food ingredient in Southeast Asia and Asia. It's lactos comes from the fruit which is a rich source of fibre, Vitamin C, B1, iron and calcium. However, it not recommended by WHO because they are against coconut oil which is a major part of coconut milk and has a high level of saturated fal 14. Cashew Nuts When cashews are blended with water, the result is a creamy liquid which is referred to as cashew milk, Cashew milk is lactose-free but the nutrients vary depending on it is made at home or bought from a commercial store. The ones that are brought from the store are fortified with varying amounts of vitamins and minerals. 15. Nut and seed-based Ss If you're looking for a dairy-free alternative to milk but don’t particularly fancy soy milk, there’s always nut and seed-based milks. Almond milk in particular 1s widely available in supermarket but dairy alternatives can also easily be made from cashews and flaxseed 16. Long-life milk Also known as UHT (ultra-high temperature) milk, long life mitk is milk that is pasteurised at much higher temperature than regular milk. Specifically, the milk is heated to above 135°C for 1-2 seconds, as opposed to regular milk which is heated to just over 70°C for 15 seconds Scanned with CamScanner (© scanned wt onENScnnerSPECIAL MILKS rocessed OF fermented those Pid behave like liquid . include his category are In mble 1 : ve products which physically rese Mt milk A ois Milk 2.1.1 Definition Sterilized milk may 6 ¢ defined as (homogenized) milk which has been heated to a temperature of 100°C or above for such lengths of time that it remains fit for human consumption for at least 7 days at room temperatures. (Commercially sterilized milk is rare- ly sterile in the strict bacteriological sense. This is because the requirements for complete sterility conflict with the consumer's preference for normal colour and flavour in the sterilized pro- duct. The spore-forming bacteria in raw milk, which are highly heat-resistant, survive the sterilization temperature-time employed in 0 dairy and ultimately lead to the deterioration of sterilized milk. 2.1.2 Requirements Sesleed ail must: (i) keep without deterioration, i.e., remait nd be of good commercial value for a sufficient period o satisfy commercial requi ii ‘quirements; i i harmful to consumer health. pO) be fie of micro-onganie and toxins; (iii) be free of » '€, pathogenic, toxinogenic germ ferate, i.e. it should hot shaw lis of bean can) th leads, inter alia, to an absence of deren in son - ration). to) a antages and disadvantages vantages: (i) remark, : refrigerated 5 (ii nae keepin iv % digestible cindy ation inne Inve os » ence useful for feeding of infants and i infa > Scanned with CamScanner © scone wih one cameSpecial Milks a : ‘rich’ flavour (due to homogenization); i se vimical to use; (vi) less liable to develop oxidized taints, ( (b) Disadvantages: (i) increased cost of production; (ii) more Joss in nutritive value than pasteurization (50 per cent of the vitamin C and 33 per cent of vitamin B originally present, are Yestroyed, and there is a slight reduction in the biological value of the milk proteins); (iii) Gerber test by normal procedure not ids; (iV) distinctive so accurate. 24.1 Method of manufacture A. In-bottle sterilization. (a) Flow diagram of manfacture. Receiving milk Cooling to $°C tnd bulk storage Pre-heating (35-40°C) Filtration/Clarifcation Cooling to °C Standardizing and storage (5°C) Pre-heating (60°C) Homogenization (2500 psi) (60°C) Clarification (60°C) Filling and cappi (in cleaned and sanitized bottles) Sterilizing (108-1 1°C/25-30 min.) Cooling (room temperature) Storage (room temperature) re? Details of manufacture. The raw milk, on receipt, should wea examined by the prescribed physico-chemical and bac- silos tests and only high-quality milk should be used for Ppl ae milk. Care should be taken to accept milk ait muni ich have no developed acidity and which contain the be promapet Of spore-forming bacteria. The intake milk shou!d accraptlY cooled to $°C for bulk storage in order to check any eficient (eeowtH Next, it should be pre-heated to 35-40°C for Mtration/clarification, so as to remove visible dist, etc., Scanned with CamScanner © scone wine scarTechnology milk should again be outline : 2 se its esthetic qual Ny ualit¥ qt should then be to incre tas 10 preserve Meenas’ of fat and solids-not. cooled 10 5 : esctided POT al standards (which vary ; ik). It must bestored yr i x conform 0 fralo mi to fat conten rate tO pot cae ‘I ould be promptly pre-heated tion o prevent any subsequent ogen! . 5 10 60 C fo omer, usually $10 jeestage homogenization formation © cream ressure efer 10 22 for more informa. Ne ig he homogenize milk must be clarihed tion on ho! ae nent f0" d 2B the homogenization ve the Se! Mizer should be filled into J i ming from the bottle. and sanitized pottles com the (hot) lee : hen sealed with special caps (of the crown d then be placed in ashing ma yal wee 7) .d bottles shoul: Process, or fed into metal crates for ee 4 . Hy the milk is steri- conveyors for the Continuous . Usua st ized at 108-111°C (225-230°F) for 25-30 minutes. The sterilized milk bottles should be gradually cooled to room temperature. Any sudden cooling may lead to bottle breakage. Finally the miik-in-bottles should be stored in a cool place. (c) Sterilizers. These may be: |. Batch; 2. Continuous. mn Bait These may either be rotary oF non-rotary in type The at (tank) sterilizers are rectangular, horizontal, boilet- shaped retorts with a steam inlet and condensate outlet, fitted with clamp-down covers, Into whi ii " veavired te ich steam is adjusted for the we perature and time for sterilization Advantages, (i) simplicity a i : oo (ii ve capital and ac ptarendtare! oT operations w e isadvantages. (i) U: ° ; sually proc i snsoked taste nthe Gnished product a sie a Gu a (ui) cooling has to be jh uct; (ii) stecilization may Jn iene of large-scale proces avoid breakage: (iv) "7 ‘ atch-rot cessing ai sihich are iat ary type, the filled bas re not obtained. beter quality te i 61pm. The ste rae are put into holde ri : 2, Coatinceae stary-type ierilizers ee milk is of a slight!) om 19, the filled idraesied ilk aa ts of carr y mea sealed milk bet ere, they chter ne water ator neat fe sterilizing zone, ¥ 7 Scanned wii mse ned with CamScanner (© scanned wt onENScnnerSpecial Milks 93 consists of a steam chamber at 108-111°C (225-230°F). Here the pottles remain for a pre-determined time, viz., 25-30 minutes, for milk sterilization. (d) Cooling. After heat-treatment in the batch/tank sterilizers, the milk bottles may be cooled in air or water. If cooling is too rapid, the bottles may crack; if too slow, there is a danger of browning due to caramelization. In the continuous system, after leaving the sterilizing zone, the bottles enter a column of hot water where the cooling process begins. This is followed by their passage through another tank of water (at a lower temperature than the previous one) for further cooling, and lastly through a shallow tank of cold water for final cooling. The bottles are then automatically discharged and conveyed to a point where they are placed in crates in which they are transferred to the storage room. B. Ultra high temperature( UHT) methods of sterilization. In these processes, the milk is heated to 135-150°C for a few seconds, gene- rally in a plate or tubular heat-exchanger. The milk, which is then almost sterile, has to be filled into containers for distribution; the filling has to be done aseptically. In many cases pre-sterilization, as above, is followed by in-bottle sterilization. 2.1.5 Distribution Once a week. This is why sterilized milk has great scope in warm countries as long as household refrigerators are not in com- mon use. 2.1.6 Tests (i) Turbidity test. (This is the official test.) (il) Bacterial couna. Note. Phosphatase test is not applicable to sterilized milk. 2.1.7 Faults The Most common is browning. Because of this fault, ‘Plain’ Sterilized milk is not so popular. Flavoured (and simultaneously Coloured) sterilized milk is more popular, aA oe Scanned with CamScannerA Peveaet Milks 2.4.1 Definition Flavoured milks are milks to which some flavours have beet added. When the ‘milk’ is used, the product should contain a mik fat percentage at least equal to the minimum legal requirement for market milk. But when the fat level is lower (1-2 per cetth Scanned with CamScanner‘Special Milks rr) the term ‘drink’ is used. 24.2 Purpose (j) to make milk more palatable to those who do not relish it as such; (ii) to stimulate the sale of milk; (iii) to put skim milk to profitable use. 24.3 Types The main types are: (i) chocolate milks/drinks; (ii) fruit flavoured milks/drinks; (iii) sterilized flavoured milks/drinks. 2.4.4 Method of manufacture of chocolate/fruit flavoured milks/ drinks (a) Flow diagram of manufacture: Receiving milk Standardization 1 Pre-heating (60°C) 1 Homogenization 2500 psi Pre-heating (35-40°C) Mixing cocoa, sugar and stabilizer OR Mixing flavourjessence, colour and sugar Pasteurization (71°C/30 min) Cooling (5°C) Bottling and storage (S°C) (b) Details of manufacture 1. Chocolate milks/drinks, The following formula may be used: (i) Cocoa powder 1 to 1.5% Gi) Sugar $ to 7.0% (ii) Stabitizer 0.2% __ (Sodium Alginate) (\) Fat level in milk/drink—Minimum legal standard 2%- fi he milk on receipt is standardized, pre-heated to 35-40°C and Hered; alternatively, after standardization it is pre-heated t0 Scanned with CamScanner © scone wih one cameTechnology Outlines of Dairy e ed at 2500 pst and then clarified. To the warm or soo unts of cocoa-mix, ugar and stabilizer ate mot Ive them properly. (The milk, the desired @! dded and surre so a! cocoa powder may also added in the Delevan stabilizer in the form of solution. ) The mixture 1S mp eurized , nr 30 minutes, cooled rapidly to 5°C, bottled and kept under see ‘ ttles are invariably inverted x i The bo! frigeration (5°C) until used. s tp and down a few times before consumption. form of syrup, and the zed milk is homogenized to prevent or delay the rising of cream. It may be homogenized after addition of cocoa and sugar, but this has the effect of increasing sedi- mentation Stabilizer is usually added to delay or prevent settling of cocoa particles; it also aids in the prevention of cream rising. Note. Standardi Il. Fruit flavoured milks/drinks. Permitted fruit flavours/es- sences, together with permitted (matching) colours and sugar are used. The method of preparation is similar to that used for choco- late milks/drinks. The common flavours used are strawberry, orange, lemon, pineapple, banana, vanilla, etc. Pure fruit juices or syrups can be satisfactorily combined with milk to form «milk shakes’. However, in order to obtain good results, the following precautions should be taken: (i) No acid (citric of tartaric) should be added to the fruit syrup, as this may cause curdling. The pH of the milk-syrup mix- ture should be about 5, which is safe from curdling. (ii) Excessively sweet syrups should be avoided. The best sugat content of the syrup is 45-55 per cent. (iii) Add 1 part of fruit syrup to 5 parts i ils which give particularly good results are eat pineapple, blackberry, raspberry and black currant ) ee (iv) Care should be taken to see that there . blend of sweet, fruity and milky flavours isa pleasant i, colour). (together with an appealiof 245M manufe These eatin ie aediteg of sterilized-flavoured milks/drinks milks/drinks. The ioethod of preeanntia Sterilized and flavou ration is given below. Scanned with CamScanner © scone wine scarSpecial Milk (8) Flow diagram of manufacture: Receiving milk 101 * Same as for Clarification Sterilized milk (2.1) Mixing flavour/essence, colour and sugar 10 Sterilized milk Storage (Room temperature) (2.1) (b) Details of manufacture. The method of Preparation consists of all the steps indicated under 2.1. In addition, in between clarifi- cation and filling, flavour or essence, permitted (matching) colour and sugar (syrup) are added and mixed into the milk. Filling and capping } Same as for Scanned with CamScanner o3 ani Milk 1 Definition oo, ; = ! a to milk prepared by dispersing whole milk powds (also called dried whole milk) in water approximately in the pra, i - ter, (Usually spray-dy; tion of 1 part powder to 7-8 parts wa y-drie ieee is used, since it is more soluble and produces less sediment) 2.9.2 Merits . (i) Helps in making up the shortage of fresh milk Supplies in developing countries; (ii) used by the Armed Forces in othe countries. 2.9.3 Method of manufacture (i) Flow diagram of manufacture: Receiving water in pasteurizing vat Pre-heating to 38-43°C Addition of whole milk powder and mixing Filtration Pasteurization (63°C/30 min) Cooling (5°C) Packaging and storage (S°C) (ii) Details of manufacture. The calculated amount of potable water is received in the pasteurizing vat/tank equipped with a0 agitator. The water is heated, while the agitator is kept in motion, to 38-43°C. Then the calculated amount of spray dried whole milk is slowly added at the point of agitation, and the mixture thoroughly agitated till it dissolves completely. Special Powde! Mixer equipment may be used for this purpose. The mixture # then pumped through a filter, pasteurized at 63°C for 30 minute and promptly cooled to 5°C or below until distribution. 4 Scanned with CamScanner oSpecial Milks 2.50” Recombined Milk 113 2.10.1 Definition This refers to the product obtained when butteroi dry/anhydrous milk fat), skim milk powder od ei called bined in the corn pasbattions to yield fluid milk. The milk fat may also be obtained from other sources, such or plastic cream. as unsalted butter Under the PFA Rules (1976), Recombined Milk should contain a minimum of 3.0 per cent fat and 8.5 per ce t soli 7 throughout the country. BARE ONE HON Te 2.10.2. Merits (i) Helps in making up the shortage of fresh milk supplies in developing countries; (ii) helps prevent price rise of liquid milk in cities. 2.10.3 Method of manufacture (i) Flow diagram of manufacture: Receiving water in pasteurizing vat Pre-heating (38-49°C) Addition of skim milk powder and mixing (38-43°C) Addition of butreroil and mixing (42-49°C) Filtration Pasteurization (63°C/30 min) Homogenization (2500 psi/63°C) Cooling (5°C) Packaging wad: storage (5°C) (ii) Details of manufacture. A calculated amount of potable Water is received in the pasteurizing vat/tank equipped with an agitator. The water is heated, while the agitator is kept in motion, toa temperature of 38-43°C. A proportionate amount of spray dried skim milk is slowly added at the point of agitation. ‘Whea the water reaches a temperature of 43-49°C, another proportionate mount of butteroil is added. These constituents are he "ated till a homogeneous mixture is obtained. The mixtt! then pumped through a filter and later pasteurized at 63°C for 30 Scanned with CamScanner © scone wih one came4 Outlines of Dairy Technology d at the pasteurization tem minutes. It is then homogenize ture at 2500 psi single stage to ensure proper emulsificatiog the milk fat. The product is quickly cooled to S°C, packageg u stored at 5°C or below until distribution. was extensively produced under the heme in the four major cities of Indi, viz. Bombay, Caicutta, Delhi and Madras, during 1979.5 from the butteroil and skim milk powder donated under the World Food Programme Project by the Food and Agr. culture Organisation of the United Nations. Note. Recombined milk ‘Operation Flood" scl 2.11 Toned Milk 2.11.1 Definition Toned Milk (also called Single Toned Milk) refers to milk obtained i by the addition of water and skim milk powder to whole milk. In practice, whole buffalo milk is admixed with reconstituted spray dried skim milk for its production. Under the PFA Rules (1976), toned milk should contain a mini- mum of 3.0 per cent fat and 8.5 percent solids-not-fat throughout the country. 2.11.2 History Toned Milk is the brainchild of D. N. Khurody (India), who is also credited with coining its name. Under his auspices, it wi first produced in 1946 in the Central Dairy of the Aarcy Milk Colony and marketed in Bombay City. Soon other cities, notably Calcutta, Madras and Delbi started producing and marketios Toned Milk, which has become a permanent feature ever since 0 the market milk industry in India, In the words of Mr Kburody* "By merely adding water to whole buffalo milk, both the fat # solids-not-fat content are reduced. But by adding skim oil powder to the mixture, solids-not-fat is ‘toned up’ or increased? tin oval level. As the product was neither whole milk iF |, @ new oi il i a : milk powder was serie lanoreesye eas given te 1 2.11.3 Merits (j) Iocreases the supply of milk. The buffalo milk initially used if Scanned with CamScannerSpecial Milks 115 / sed by 100-150 per cent; (ii) reduces the price Of milk, t0 as pees lower-income groups of the Population, 114 Method of manufacture 4) Flow diagram of manufacture: é Receiving water in pasteurizing vat Pre-heating (38-43°C) Addition of skim milk powder and mi: addition of whole buffalo milk and Filtration Pasteurization ksrcp0 min.) Cooling (5*C) Packaging and storage (5°C) (ii) Calculation Problem: Given: 1,000 kg of whole buffalo milk testing 7.5%, fat and 9.8% SNF; SMP testing 0.5% fat and 96.5% SNF; Toned Milk to contain 3.0% fat and 8.5% SNF. Solution. Let the amount of water Tequired be W kg and SMP be S kg. Amount of Toned Milk = (1000 + W + S) kg. The following equations can be formed: 7.5 0.5 (1000 x fg) + (sx $8) = (1000+ W+45) x as +++(1) Fat equation) 9.8 96.5 (1000 x ip) + (8 $63) = (1000+ W +5)x £3... (SNF equation) Solving the above equations, W = 1382.1 kg i S= 1415 at = Water Desa of manufacture. The calculated amount of potable Atitaton "sceived in the pasteurizing vat/tank equipped with an to Maye’ Water is heated while the agitator is kept in motion eC: Then a proportionate amouat of spray dried skim Slowly added at the Point of agitation and the mixture |, Scanned with CamScanner116 Outlines of Dairy rede WA agitated till it dissolves completely. A Caleulat, eek buffalo milk is now added and para again agitated thoroughly till a homogeneous est ged et The mixture is then pumped through a filter, is nt - 3° for % } minutes, rapidly cooled to 5°C, packaged and kept at 5°C or beloy, until distribution. 2.12 Double Toned Milk 2.12.1 Definition Same as Toned Milk, except that under the PFA Rules (1976), Double Toned Milk should contain a minimum of 1.5 per cent gt and 9.0 per cent solids-not-fat throughout India. 2.12.2 History Same as for ‘Toned Milk’, 2.12.3 Merits but to conform to ‘Double 2.124 Method of manufacture Toned Milk’ standards, te Humanized Milk om i ane milk is so modified in its chemical Milk, mbles human milk, it is called Humanized Scanned with CamScanner oOnit- Scanned with CamScanner © scanned wth onEN Scanner$2 ation Condensed milks are the products obtained by evaporating part of the water of whole milk, or fully or partly skimmed milk, with or without the addition of sugar. The term ‘condensed’ milk is com- monly used when referring to ‘full-cream sweetened condensed milk’, while the term ‘evaporated milk’ is commonly used when referring to ‘full cream unsweetened condensed milk’. Skimmed milk products are known as ‘sweetened condensed skim milk’ and ‘unsweetened condensed skim milk’ respectively. The ratio of con- centration of milk solids is about 1:2.5 for full-cream products and 1:3 for sweetened condensed skim milk. According to the PFA Rules (1976) the various condensed milks have been specified as follows: Unsweetened condensed milk (evaporated milk) is the product obtained from cow or buffalo milk or a combination thereof, or from standardized milk, by the partial removal of water. It may contain added calcium chloride, citric acid and sodium citrate, “Source: Dairying in India, an IDSA Publication, XIII Dairy Industry Conference, Ludhiana, 1976. Scanned with CamScannerOutlines of Dairy Technology ~ ic acid and polyph. hosphoric Phosph sodium salts of orthop yy weight of the finished Product « ey cent b exceeding 0.3 Pet Yeclared on the label. Unsweeteney th ag, not be 8.0 per cent ‘ond wt should contain not less than Ps milk fa, a 36.0 per cent milk solids. Te nceed voened ik is ihe produ obtained from coy. Ik or a combination thereof, or from standardizeg ,,.” boffalo mi | removal of water and after addition of cane , pie Paain added refined lactose, calcium chloride, citrig saved citrate, sodium salts or orthophosphoric acid ang nh, phosphoric acid not exceeding 0.3 per cent by weight of the gg, ed product. Such additions need not be declared on the labe Sweetened condensed milk should contain not less than 90 per cent milk fat, not less than 31.0 per cent total milk solids and not ies than 40.0 per cent cane sugar. Unsweetened condensed skim milk (evaporated sk immed milk) isthe product obtained from cow or buffalo skim milk or a combination thereof by the partial removal of water. It may contain added calcium chloride, citric acid and sodium citrate, sodium salts of orthophosphoric acid and polyphosphoric acid not exceeding 0.3 per cent by weight of the finished product. Such additions need aot be declared on the label. Unsweetened condensed skimmed milk should contain not less than 20.0 per cent total milk solids. The fat content should not exceed 0.5 per cent by weight Sweetened condensed! shim milk is the product obtained from co or buffalo skimmed milk or a combination thereof by the partial waded vere hye after addition of cane sugar. [t may coat! civ: ina diet chloride, citric acid and ae id aos cueelinent onhephosphoric acid and pels poo Such additions need ct be aes by weight of the finished Pox shad al i leclared on the label Swectened : otal milk solids and ould contain not less than 26.0 Pee fat content should not ot less than 40.0 per cent cane suBat exceed 0.5 per cent by weight. de 4 a Composition and Standards (a) The gross c; ‘OMPosition of i oe . eeteaed, whole of ‘skim, ig ferety Scanned with CamScanner (© scanned wt onENScnnerCondensed Milks 271 TABLE 8.1 Gross composition of condensed milks (percentage) ; 7 it at TMS condensed mil UK USA UK USA ——— Condensed milk 90 79 31.0 25.9 Evaporated milk 9.0 85 310 28.0 Sin sweetened - — 20.0 20.0 stim unsweetened _ - 26.0 240 (b) The detailed composition of condensed milks is given in Table 8.2. TABLE 8.2 Detailed composition of condensed milks (percentage) Type of Milk Totals. Total Pro: Lac- d . Water TOt@l Fat solids. Pre Ash milk milk solids wetter tein tose ils POs Condensed milk 26.0 74.0 90 220 83 122 1.5 31.0 43.0 Evaporated milk 31.0 69.0 90 220 83 122 15 310 — Skim sweetened 29.0 71.0 0.5 25.5 9.3 140 22 26.0 45.0 Note; Composition of unsweetened condensed skim milk has not been included, as this product is rarely manufactured. (c) The Indian Standard specifications for sweetened condensed milks, whole or skim, are given in Table 8.3. TABLE 8.3 Indian Standard specifications for condensed milks (vide IS : 1166, 1973) ee Requirements for Characteristics : es Condensed milk Skim sweetened Total milk soli 7 ids (% wt.) Min 31.0 26.0 sain) Not less than 9.0 Not more than 0.5 arose (% wi.) Min w 40 Bact % Hectic) Max 0.35 0.35 Cofgitl COUnt (per g.) 500 soo ealotm count (per .) ee on and mould (per count 0 im — Scanned with CamScanner © scone wih one came272 Outlines of Dairy Technology 8.4 Food and Nutritive Value of Condensed and Evaporated Milks Both have high nutritive value. Both are rich in fat and fat-soluble vitamins A, D, E and K, body-building proteins, bone-forming minerals and energy-giving lactose. Further, while condensed milk is especially high in energy-giving sucrose, evaporated milk is suit- able for infant feeding since it makes a soft curd which is easily digested. Note: There is some loss of vitamin B, (30-50%) and vitamin C (60-100%) caused by sterilization in evaporated milk. How- ever, milk is a poor source of vitamin C. Sterilization is reported to have a minor effect on the biological value 4 digestibility of milk-proteins. Scanned with CamScanner oVc Cream Ice cream is a very popular product in Western countries. It is becoming popular in our country also. The demand for ice cream has recently increased, particularly in towns and cities. Ingredients Icecream is a frozen dairy product. It contains a variety of dairy ingredients. These include whole milk, skim milk, cream, butter, butteroil (which contains 99 per cent butter fat), condensed milk products and dried mit products. Milk fat and milk solids-not-fat constitute about 60 per cent of the total solids of icecream. These components give icecream a rich flavour, improved body and texture. In addition to dairy products, icecream contains sugar, stabilizer, emulsifier, flavouring material, water and air. The mixture of these ingredients, before air is incorporated and the mixture frozen, is known as icecream ix. Milk and cream are sources of butterfat, proteins, and milk sugars. Butterfats, add rich flavour, smooth texture, body and good melting properties. The triglycerides in butterfat melt over a wide range of temperatures, so there is some bit of solid and some liquid butterfat. Some of the butterfat almost turns into butter while the icecream is churned, adding to the unique texture of icecream. The proteins help to incorporate air into the mixture, helping to form small’bubbles of air. They modify the texture of the icecream in other ways as well, making it chewier, and giving it body. The proteins also help to emulsify the fats, keeping the fat globules suspended in the mix. The proteins coat each fat globule, keeping them from sticking together. However, making the globules stick together in chains and mesh-like structures is important in giving icecream its texture and ability to hold air, and its ability to stay firm as the ice inside melts. The milk sugar lowers the freezing point of the water in the icecream adding extra sweeteners, such as sugar and corn syrup, also have this effect. This ensures that a portion of the water never freezes, preventing the icecream from becoming a solid chunk of ice. Added sweeteners are inexpensive, and make up about 15 per cent of the mix by weight. The use of high-fructose corn syrup will reduce the freezing point further than sugar, resulting in a softer icecream, Stabilizers are used to prevent the formation of ice crystals during freezing, They form gels with the water in the formula and thereby improve the body and texture of the icecream. Scanned with CamScanner (© scanned wt onENScnnerir eed and cellulose Compounds generally used as stabilizers are gums, gelatin, seaw derivatives, such as carboxy-melhyl cellulose Pinisieeeen te, Emulsifiers help disperse the fat globules shih the mi ne eee zing- mixing operati clumping together during the freezing s emultien Mono a gees yg icecream dry and stiff, Egg-yolk is a natural goo ‘ : commercial preparations used. Y Composition of Icecream 4 s used in its preparatig, The composition of icecream varies depending upon the ingredient: ig The percentage composition of a good icecream is: milkfat, 12; milk solids-not-fats, 5 Bar, | stabilizer, 0.2; emulsifier, 6.2, and a trace of vanilla, This composition is exclusive of air, j. they are based on the weight of icecream mix. But icecream is a whipped product and Contains a great deal of air to prevent it from being too dense, tov hard and too cold in the mouth, The tot al solids work up to about 38.4 per cent, the remainder would be water. |, ingredients, such as nuts, fruits, chocolate and additional flavour are added, the COMpositig of course, changes, Different flavours of icecream in varied forms, markets time and again. The most popular ones include Black Raspberry, Blueberry, Butter Krunch, Butter Pecan, Butterscotch, Cherry Vanilla, Chocolate Chip, Chocolate Walnut, Coconut, Coffee, Ginger, Grapenut, Lemon, Maple Walnut, Mocha Chip, Orange Pineapple, Peanut Butter, Pistachio, Strawberry Cheesecake, Black Currant, ete such as cups, cones, candies, etc., have hit th The latest trend in icecream is bi decadence. The current advanc health. Probiotics (healthy bact Breatly reduced carbohydrates Another area is introducing omi alancing healthful ingredients with the need for alittle es in icecream and frozen desserts are in 'eria that aid digestion) in icecre: and fats are some of the most Promisi ega-3 and omega-6 and others are in the early stages of successfully Creating icecreams that incorporate these acids found in high concentrations in fish oil and that still taste 200d to consumers in Preliminary tests, . areas related to well as icecreams with Ng research being don fatty acids into icecreams. Researchers ¥ Preparation of Icecream In the preparation of icecream, the liquid constituents are heated ingredients are added to the warm liquid, which helps dis Pasteurized at 71°C for 30 min. or HTST pasteurized posteurizer is next homogenized, This helps to improve the body The homogenized mix is cooled to 4.4°C. The helps melted fat to solidify and stabilize, viscosity of the mix. These ch air into icecream The aged mix and air are passed through a freezer. The freezer will be provided with spec! mixing elements, which beat the icecream mix and subdivide air cells and evenly distribute (0 Rive a frozen foam. Also, the temperature of the mix comes down to 5 §°C, to 43°C, sugar and dry solve theyn. 7 he mix is now at 82°C for 25 «1 $. The hat mix from th and Lexture of iceere am Cooled mix is aged tor 4 to 24 hours, and milk proteins to swelt,’res anges help in whipping and Ageing sulting in the increase incorporation of required amu Froozine 1 Scanned with CamScanner (© scanned wt onENScnnerbe quick to prevent the growth of large crystals that would coarsen the texture of the ice cream. As the air is whipped into the semi-frazen mixture there is a swelling of the volume, which is known as overrun. At-5.5°C all the water will not be frozen and the semi-solid icecream is put into containers in which the ice cream is sold. The containers, with the icecream, are then placed in hardening rooms where the temperature is about - 34°C. At this temperature, the remaining water freezes and makes icecream stiff, when it is ready for sale. For making icecream in homes, a metal container with a paddle inside is used. The icecream mix is passed into the container and placed in an outside container, usually made of some poor conductor of heat, such as wood, containing a freezing mixture of ice and salt in the proportion of one part of salt to six parts of ice. The mixture is then agitated with the paddle. This helps the cooling and incorporation of air in the mixture. A oerects IN ICE CREAM & OVER RUN Flavor Defects Flavour is the most important sensory attribute in judging and grading of ice cream and frozen desserts. Even a minor flavour defect in ice cream will affect its acceptability by the consumer. Some of the prominent flavour defects are discussed in this chapter along with their causes and prevention. High flavor This flavor condition, when it occurs, is best recognized when the sample is first placed into the mouth. The intensity of the flavoring seems so striking or sharp that the desired, pleasant flavor blend is not achieved due to the harsh tones imparted by the flavoring level observed in the product. Ice cream that is too highly or excessively flavored is not severely criticized as a rule, especially if the quality of the flavoring used is high. An associative “ethanol-like” note may be present. Too sweet An ice cream that is observed to be excessively sweet tends to exhibit a candy-like taste sensation; this defect is readily noted upon the first stages of tasting. T90 much sugar (or other form of sweetener) tends to interfere with the overall desirable blend of flavors) Another unfortunate characteristic of a given ice cream that is perceived as being too sweet is a general lack of refreshing property, Lacks sweetness An ice cream that lacks sweetness is readily noted upon tasting; the product simply manifests a distinct flat or bland taste. The desired or anticipated blend of flavor is missing. An adequate amount of sweetener is required to bring out the full flavor “ ‘bloom’ ina given flavor, whether it 1s vanilla, fruit, or chocolate ice cream Scanned with CamScanner (© scanned wt onENScnner4 in certain forms of COFN Syrups ered in ce syrupy /Malty flavour s still commonly encoun ner off flavor i This sweeter mi racterist; ‘on descriptor for this chat ic is the com! caramel, i . ight be malty, 8, n syrup solids; hence “syrup flavo syrup flavor mig! con del nl scriptions for 5) lect. Frequently encountered dest ‘ noe molasses-like or similar to low levels of burnt sug ti ks fine flavour tear kecreen tie ei Thscrsmis geveray used describe an to ust barely fall short of being This critic less than clear reason, it seems _ ‘ecognize the desirable, i les . ble tor : eral" wiht ate ice cream judges are al hould remembe, “perfect” or “ideal” experienced ice ice judge shou * ere nlanced Rrvr notes of a high quality flavor. The no delicate, balance , terms. itive or specific hat “lacks fine flavor” is not readily described in more defini that “la Lacks flavouring 's basically “good” or “very tof leficient in the amount Anice cream with this defect is often criticized as flat, vanier set mpreirane added flavoring, Even though the ice cream may be pleasantly : vee eo a dairy ingredient off-flavor, it seems to lack the characteristic delicate vanilla; the desired intensity is missing, Acid (Sour) 4n acid or sour af flavor in frozen dairy desserts may be distinguished from other off- {lavors by a sudden, tingly, taste sensation (on the tip or top of the tongue), plus an associated “clean and refreshing” Of acid whey in the ice cream mix, The off activity at elevated temperature; Cooked flavour The “cooked” flavar of ice cream is com: “eee-like,” “sulfide,” NceG.ILis also referred to as “ ed milk, oF caramel-like. Cooked lor * itis so intense as to be monly, the dairy ingredients asteurized Cream mix must also be re-paste "kely to produce some depree of cooked ff 'ncorporated into ice cream which has been p; the blended or final ice already; regulations re. urized, Additional he: favor in the mix, * quire that ‘at Leatinent i Lacks freshness (Stale) The descriptor, “tacks freshness," or “stale,” eles to a moderate otf flavor of and related frozen desserts This flavor detect ig Bene Benerally assumed to re 100 Of the mix during Storage, or f at auality dairy inpredionts jn Mix formulation, Sult from eitiy marpin: dients Scanned with CamScanner (© scanned wt onENScnner