Lecture 2:MATURITY INDICES,HARVESTING ANDPOST HARVEST

HANDLING OF FRUITS AND VEGETABLES

I. MATURITY
It is the stage of fully development of tissue of fruit and vegetables only after which it
will ripen normally. During the process of maturation the fruit receives a regular supply of food
material from the plant. When mature,the abscission or corkylayer which forms at the sternend
stops this in flow. Afterwards, the fruit depend on its own reserves, carbohydrates are dehydrated
and sugars accumulate until the sugar acid ratio form. In addition to this, typical flavour and
characteristic colour also develop. it has been determined that the stage of maturity at the time of
picking influence the storage life and quality of fruit, when picked immature like mango develop
white patches or air pockets during ripening and lackingin normal brix acid ratio or sugar acid
ratio, taste and flavour on theother handif the fruits are harvest edover matureor full ripe they are
easy susceptible to microbial and physiological spoilage and their storage life is considerably
reduce. Such fruits persist numerous problems during handling, storage and transportation.
Therefore, it is necessary or essential to pick up the fruits orvegetables at correct stage of
maturity to facilitate proper ripening, distant transportation and maximum storage life.
Horticultural maturity
It is a developmental stage of the fruit on the tree, which will result in a satisfactory
product after harvest.
Physiological maturity
It refers to the stage in the development of the fruits and vegetables when maximum
growth and maturation has occurred. It is usually associated with full ripening in the fruits. The
Physiological mature stage is followed by senescence.
Commercial maturity
It is the state of plant organ required by a market. It commonly bears little relation to
Physiological maturity and may occur at any stage during development stage.
Harvest Maturity
It may be defined in terms of Physiological maturity and horticultural maturity, it is a
stage,whichwillallow fruits / vegetables atits peakcondition whenit reaches tothe consumers and
develop acceptable flavour or appearance and having adequate shelf life.
Table1:Criteriaof maturityforharvestingfruitsandvegetables

Fruit Physical Chemical

Mango Olive green colour with clear lenticels, Starch content,flesh colour
Shoulder development size sp.gravity, days
from fruit set.

Banana Skin colour, drying of leaves of the plant, Pulp/peelratio,starchcontent

brittleness of floral ends, angularity of the
fruit,and days from emergence of
inflorescence.

Citrus Colour break of the skin from green to Sugar/acidratio,TSS

orange,size
Grapes Peelcolour,easy separation of berries, TSS 18-12 Thompson seedless,
characteristic aroma 12-14 for Bangalore Blue,
14-16forAnab-e-shahi

Apple Coloursize Firmness as measured by

Pressuretester
Papaya Yellow patch or streaks. Jelliness of the seed, seed
Colour

Vegetables are harvested at harvest maturity stage, which will allow it to be at its peak
condition when it reaches the consumer, it should be at a maturity that allows the produce to
develop an acceptable flavour orappearance,it shouldbe at asizerequired by the market,and
should have an adequate shelf life. Time taken from pollination to horticultural maturity under
warm condition, skin colour, shape, size and flavour and abscission and firmness are used to
assess the maturity of the produce.

Table2:Time taken from pollination to horticultura lmaturity

S.No. Vegetables Time to harvest

Maturity(days)
1. Ridgegourd 5-6
2. Squash 7- 8
3. Brinjal 25-40
4. Okra 4- 6
5. Pepper(greenstage) 45-55
6. Pepper(redstage) 60-70
7. Pumpkin(mature) 65-70
8. Tomato(maturegreen) 35-45
9. Tomato(redripestage) 45-60
10. Peas 30-35
Skin colour
Loss of green colour in citrus and red colour in tomato.
Shape, size and flavour
Sweet corn is harvested at immature stage, smaller cobs marketed as baby corn. Okra and cow pea are
harvested at mature stage (pre fiber stage). In chilli, bottle gourd, bitter gourd, cluster beans maturity is
related to their size. Cabbage head and cauliflower curd are harvested before un pleasant flavour.
Abscission and firmness
Musk melon should be harvested at the formation of abscission layer. In cabbage and lettuce should be
harvested at firmness stage.
Factors affecting maturity
1. Temperature: Higher temperature gives early maturity. e.g. Gulabi (Pink) grapes mature in 100 days in
Western India but only 82 days are enough in the warmer Northern India. Lemon and guava takes less time
to mature in summer than in winter. Sun-scorched portions of fruits are characterized by chlorophyll loss,
yellowing, disappearance of starch and other alcohol insoluble material, increase in TSS content, decrease in
acidity and softening.
2. Soil: Soil on which the fruit tree is grown affects the time of maturity. e.g. Grapes are harvested earlier on
light sandy soils than on heavy clays.
3. Size of planting material: This factor in propagated fruits affects fruit maturity. e.g. In pineapple, the
number of days taken from flowering to fruit maturity was more by planting large suckers and slips than by
smaller ones.
4. Closer spacing: Close spacing of hill bananas hastened maturity.
5. Pruning intensity: It enhanced the maturity of Flordasun and sharbati Peaches.
6. Girdling: Process of constricting the periphery of a stem which blocks the downward translocation of
CHO, hormones, etc. Beyond the constriction which rather accumulates above it. In Grape vines it hastens
maturity, reduces the green berries in unevenly maturity cultivar and lowers the number of short berries. It is
ineffective when done close to harvest. CPA has an additive effect with girdling
MATURITY INDEX
Maturity index
The factors for determining the harvesting of fruits, vegetables and plantation crops according to
consumer’s purpose, type of commodity, etc and can be judged by visual means (colour, size, shape),
physical means (firmness, softness), chemical analysis (sugar content, acid content), computation (heat unit
and bloom to harvest period), physiological method(respiration). These are indications by which the
maturity is judged. Various index are as Follows;
1. Visual indices
It is most convenient index. Certain signals on the plant or on the fruit can be used as pointers. E.g. drying
of top leaves in banana, yellowing of last leaf of Peduncle in jackfruit. Flow of sap from cut fruit stalk of
mango slows down if the harvest is done after maturity but in immature fruits, exudation is more and comes
with force in a jet form. in papaya, the latex becomes almost watery. The flow gets reduced on maturity in
Sapota. In fruits like banana and Sapota, floral ends become more brittle and shed with a gentle touch or
even on their own. In Sapota, the brown scurf on the fruit skin starts propping. In mango, lenticels become
more prominent and the waxy bloom gradually disappears. Grapes develop translucent bloom. Other
changes like angularity in banana, development of creamy wide space between custard apple segments and
the flattening of the eyes in pineapple and tubercles in litchi serve as reliable maturity indices.
2. Seed development
It can also be used as an index of fruit maturity, e.g. endocarp hardening for stone and fiber development for
dessert in mango.
3. Start of bud damage
Occasionally it can be used as an index of fruit maturity in mango.
4. Calendar date
For perennial fruit crops grown in seasonal climate which are more or less uniform from year to year,
calendar date for harvest is a reliable guide to commercial maturity. This approach relies on a reproducible
date for the time of the flowering and a relative constant growth period from flowering through to maturity.
Time of flowering is largely dependent on temperature, and the variation in number of days from flowering
to harvest can be calculated for some commodities by use of the degree- concept.
5. Heat units
Harvest date of newly introduced fruits in a widely varying climate can be predicted with the help of heat
unit. For each cultivar the heat requirement for fruit growth and development can be calculated in terms of
degree days: Maturity at higher temperature is faster as the heat requirement is met earlier. This heat unit
helps in planning, planting, harvesting and factory programmes for crops such as corn, peas and tomato for
processing.
MATURITY OF FRUITS AND VEGETABLES
Banana
The fruit is harvested when the ridges on the surface of skin change from angularity to round i.e. after the
attainment of 3% full stages. Dwarf banana are ready for harvest within 11- 14 months after planting while
tall cultivars takes about 14-16 months to harvest. Peel colour change from dark green to light green the
remaining style ends were dry, and brittle and fruits were less angular in shape.
Guava
TSS acid ratio, specific gravity and colour are determined the maturity in guava. For e.g.
Allahabad safeda - 35.81
Apple colour guava - 26.39
Chittidar guava - 28.13
Lucknow - 49 -34.25
Specific gravity - Less than I
Colour - Light green to yellow.
Ber
In ber maturity is judged by colour (yellow), specific gravity (less than 1) and TSS
Pomegranate
Sugar percentage should be 12-16% and acid percentage 1.5—2.5%, variety Ganesh harvest when seed
colour becomes pink. In this stage TSS 12.5% and sugar acid ratio 19.5%.
Bael
It takes one year for fruiting after flowering. It is the fruit which ripen after one year of flowering. April start
harvesting and may end it start in flowering.
Mango
This can be judged when one or two mangoes ripen on the tree are fall on the ground of their own accord.
This process of fallen is known as tapaca specific gravity 1,01—1.02 and TSS
10-14%.
Table3. Maturity indices of vegetable crops

Root,bulbandtubercrops Maturityindices
Radish and carrot Large enough and crispy
Potato,onion and garlic Tops beginning to dry and topple clown
Yams,bean and ginger Large enough
FRUITVEGETABLES
Cowpea,snapbean,sweetpea, Well filled pods that snapreadily
Winged bean
Lima bean and pigeonpea Well filled pods that are beginning to loset heir
greenness.
Okra Desirable size reached and the tips of which can be
Snapped readily
Snakegourd Desirable size reached and thumbnail can still
Penetrate flesh readily
Eggplant,bittergourd,slicing Desirable size reached but still tender
cucumber
Tomato Seeds slipping when fruit is cut,or green colour
Turning pink
 Muskmelon Easily separated from vine with as light twist leaving
Clean cavity(full slip stage).
Watermelon Dull hollow sound whent humped
FLOWER VEGETABLES
Cauliflower Curd compact
Broccoli Bud cluster compact

II. HARVESTING
The goals of harvesting are to gather a commodity from the field at the proper level of maturity with a
minimum of damage and loss, as rapidly as possible and at a minimum cost. This is achieved through hand-
harvesting in most fruit, vegetable and flower crops.
1. Hand Harvesting
Hand harvesting has a number of advantages over machine harvest. People can accurately determine
product quality, allowing accurate selection of mature product. This isparticularly important for crops that
have a wide range of maturity and need to be harvested several times during the season. Properly trained
workers can pick and handle the product with a minimum of damage. Many fresh-market products have a
short shelf life if they are bruised or damaged during harvest and handling. The rate of harvest can easily be
increased by hiring more workers. Hand- harvesting also requires a minimum of capital investment. The
main problem with hand harvesting is labor management. Labor supply is a problem for growers who
cannot offer a long employment season. Labor strikes during the harvest period can be costly. In spite of
these problems, quality is so important to marketing fresh- market commodities successfully that hand
harvesting remains the dominant method of harvest of most fruits and vegetables and for all cut flowers.
Effective use of hand labor requires careful management. New employees must be trained to harvest the
product at the required quality and at an acceptable rate of productivity. Employees must know what level of
performance and must be encouraged and trained to reach that level.
2. Mechanical Harvesting
Mechanical harvest is currently used for fresh-market crops that are roots, tubers, or rhizomes and for nut
crops. Vegetables that are grown below ground (radishes, potatoes, garlic, carrots, beets and others) are
always harvested only once and the soil can be used to cushion the product from machine caused
mechanical injury. Tree nuts and peanuts are protected by a shell and easily withstand mechanical handling.
A number of products destined for processing such as tomatoes, wine grapes, beans, peas, prunes,
peachesand some leafy green vegetables are machine harvested because harvest damage does not
significantly affect the quality of processed product. This is often because the product is processed quickly
after harvest. These crops have also been amenable to new production techniques and breeding that allow
the crop to be better suited to mechanical harvest.
The main advantage of mechanical harvest equipment is that machines can often harvest at high rates. Tree
nut harvesters, for eg. attaching a shaking mechanism to the tree and remove most of the nuts in few
seconds. The nuts are either caught on a fabric- covered frame or picked up from the ground by other
machines. This allows an orchard to be harvested very quickly compared to handshaking with poles.
Machine harvest also reduces management problems associated with workers. The commodity must be
grown to accept mechanical harvest.
Demerits of Mechanical Harvesting
Machines are rarely capable of selective harvest. Mechanical harvesting will not be feasible until the crop or
production techniques can be modified to allow one time harvest. Harvesting machines often causes
excessive product perennial crops eg. Bark damage from a tree shaker. The harvesting machines are quite
expensive.
III. POST HARVEST HANDLING
Being living organs, fruits and vegetables continue to respire even after harvesting when they have a limited
source of food reserves. In addition to degradation of respiratory substrates, a number of changes in taste,
colour, flavour, texture and appearance take place in the harvested commodities which make them
unacceptable for consumption by the consumers if these are not handled properly. Post harvest technology
starts immediately after the harvest of fruits and vegetables. The whole process of processing the
commodities is categorized as Handling of fresh produce. Post harvest Technology of fresh fruits and
vegetables combines the biological and environmental factors in the process of value addition of a
commodity.
1. Precooling
Precooling (prompt cooling after harvest) is important for most of the fruits and vegetables because they
may deteriorate as much in 1 hr at 32°C. In addition to removal of field heat from commodities, precooling
also reduces bruise damage from vibration during transit. Cooling requirement for a crop vary with the air
temperature during harvesting, stage of maturity and nature of crop. There are many methods of precooling
viz, cold air (room cooling, forced air cooling), cold water (hydrocooling), direct contact with ice (contact
icing), evaporation of water from the produce (evaporative cooling, vacuum cooling) and combination of
vacuum and hydrocooling (hydrovac cooling). Some chemicals (nutrients/growth regulators/ fungicides) can
also be mixed with the water used in hydrocooling to prolong the shelf life by improving nutrient status of
crop and preventing the spread of post harvest diseases.
2. Washing, Cleaning and Trimming
Before fresh fruits and vegetables are marketed various amounts of cleaning are necessary which typically
involves the removal of soil dust, adhering debris, insects and spray residues. Chlorine in fresh water is
often used as disinfectant to wash the commodity. Some fungicides like Diphenylamine (0.1 - 0.25%) or
ethoxyquin (0.2 - 0.5%) may be used as post harvest dip to control the disorders. Eg. Apple superficial
scald. For cleaning of some fruit type vegetables (melons, brinjals, tomatoes, cucumber) they should be
wiped with damp cloth. Many vegetable need trimming, cutting and removal of unsightly leaves or other
vegetative parts.
3. Sorting, Grading and Sizing
Sorting is done by hand to remove the fruits which are unsuitable to market or storage due to damage by
insects, diseases or mechanical injuries. The remainder crop product is separated into two or more grades on
the basis of the surface colour, shape or visible defects. For eg, in an apple packing house in India 3 grades
viz. Extra Fancy, Fancy and standard may be packed for marketing. The fourth “cull” grade is meant for
processing. After sorting and grading, sizing is done either by hand or machine. Machine sizers work on two
basic principles: weight and diameter. Sizing on the basis of fruit shape and size are most effective for
spherical (Oranges, tomato, certain apple cultivars) and elongated (Delicious apples and European pears or
of non-uniform shape) commodities, respectively.
4. Curing
Curing is an effective operation to reduce the water loss during storage from hardy vegetables viz, onion,
garlic, sweet potato and other tropical root vegetables. The curing methods employed for root crops are
entirely different than that from the bulbous crops (onions and garlic). The curing of root and tuber crops
develops periderms over cut, broken or skinned surfaces wound restoration. It helps in the healing of harvest
injuries, reduces loss of water and prevents the infection by decay pathogens. Onions and garlic are cured to
dry the necks and outer scales. For the curing of onion and garlic, the bulbs are left in the field after
harvesting under shade for a few days until the green tops, outer skins and roots are fully dried.
5. Waxing
Quality retention is a major consideration in modem fresh fruit marketing system. Waxes are esters of
higher fatty acid with monohydric alcohols and hydrocarbons and some free fatty acids. But coating applied
to the surface of fruit is commonly called waxes whether or not any component is actually a wax. Waxing
generally reduces the respiration and transpiration rates, but other chemicals such as fungicides, growth
regulators, preservative can also be incorporated specially for reducing microbial spoilage, sprout inhibition
etc. However, it should be remembered that waxing does not improve the quality of any inferior horticulture
product but it can be a beneficial adjunct to good handling.
The advantages of wax application are:
- Improved appearances of fruit.
- Reduced moisture losses and retards wilting and shrivelling during storage of fruits.
- Less spoilage specially due to chilling injury and browning.
- Creates diffusion barrier as a result of which it reduces the availability of 02 to the tissues thereby reducing
respiration rate.
- Protects fruits from micro-biological infection.
- Considered a cost effective substitute in the reduction of spoilage when refrigerated storage is
unaffordable.
- Wax coating are used as carriers for sprout inhibitors, growth regulators and preservatives.
The principal disadvantage of wax coating is the development of off- flavour if not applied properly.
Adverse flavour changes have been attributed to inhibition of O2 and CO2 exchange thus, resulting in
anaerobic respiration and elevated ethanol and acetaldehyde contents. Paraffm wax, Carnauba wax, Bee
wax, Shellac, Wood resins and Polyethylene waxes used commercially.
6. Packaging
Proper or scientific packaging of fresh fruits and vegetables reduces the wastage of commodities by
protecting them from mechanical damage, pilferage, dirt, moisture loss and other undesirable physiological
changes and pathological deterioration during the course of storage, transportation and subsequent
marketing. For providing, uniform quality to packed produce, the commodity should be carefully supervised
and sorted prior to packaging. Packaging cannot improve the quality but it certainly helps in maintaining it
as it protects produce against the hazards of journey. Striking developments have been in the field of
packaging of horticultural produce and the gunny bags, grasses and stem leaves used so far for packaging
are now being replaced by a variety of containers such as wooden boxes, baskets woven from bamboo or
twigs, sack/jute bags and corrugated fibre board (CFB) boxes.
7. Storage
A number of storage techniques (ground storage, ambient storage, refrigerated storage, air cooled storage,
zero energy storage, modified atmospheric storage, hypobaric storage and controlled atmosphere storage)
are being used for fruits and vegetables depending upon the nature of the commodity and the storage period
intended.