RRL OUTLINE

 COMMODITY
-production
-properties
 Osmosis
 Osmotic dehydration
 Osmotic agent

 Solid gain
 Sensory evaluation
 Drying rate
 Drying temperature
 Use of sugar in osmotic dehydration
 Existing studies on osmotic dehydration of commodity
 Existing studies on UAOD of commodity
 Ultrasound
 Principle of ultrasound
 Methods of ultrasound
 Ultrasonic equipment
 Ultrasound application in fruits and vegetables
 Moisture loss
 Moisture content
 Equilibrium moisture content
 Henderson and pabis model
 Newton(lewis) model
 Page model


OSMOSIS
OSMOTIC DEHYDRATION
OSMOTIC AGENTS
SUGAR
PINEAPPLE
EQUILIBRIUM MOISTURE CONTENT
SOLID GAIN
SENSORY EVALUATION
DRYING MODEL
DRYING TEMPERATURE
DRYING RATE

Pineapple
Pineapple [Ananas comosus (L.) Merr.] is a tropical fruit with exceptional juiciness, vibrant tropical
flavor and immense health benefits. Mature fruit contains sugar, a protein digesting enzyme
bromelin, citric acid, malic acid, vitamin A and B. It can be used as supplementary nutritional fruit for
good health with an excellent source of vitamins and minerals and contains considerable calcium,
potassium, fiber, and vitamin C. Pineapple is the third most important tropical fruit in the world after
banana and citrus (Rohrbach et al.,2003). The five leading pineapple producing countries are Costa
Rica, Brazil, Philippines, Thailand and Indonesia (FAO STAT, 2013). These countries produce the fruit
primarily for fresh fruit markets and the processing industry. It can increase national income through
the expansion of local industries and higher incomes for farmers involved in its production. This fruit
is much liked and popular all over the world. Pineapples may be cultivated from a crown cutting of the
fruit, possibly flowering in 20-24 months and fruiting in the following six months
file:///C:/Users/mariz/Downloads/ajol-file-journals_110_articles_149223_submission_proof_149223-
1309-392702-1-10-20161208.pdf

Pineapple may be consumed fresh, canned, juiced, and are found in a wide array of food stuffs -
dessert, fruit salad, jam, yogurt, ice cream, candy, and as a complement to meat dishes. Like the other
fruit, pineapple has vitamins, minerals, fiber and enzymes that is good for the digestive system and
helps in maintaining ideal weight and balanced nutrition. Pineapple is a good source of Vitamin C .
Pineapple has minimal fat and sodium with no-cholesterol. It is believed to protect against cancer and
break up blood clots and is beneficial to the heart (Arcelo, n.d.).

In the Philippines, Pineapple is extensively cultivated in the Northern Mindanao, SOCCKSARGEN

(Southern Cotabato, Cotabato Province, Sultan Kudarat, Sarangani, General Santos City), Bukidnon,
Bicol and CALABARZON (Cavite, Laguna, Batangas, Rizal, Quezon) for domestic and foreign markets
either fresh and for processing (Arcelo,
n.d.).https://library.buplant.da.gov.ph/images/1641883999Pineapple%20%20Production
%20Guide.pdf

The top five (5) fruits in the region by volume of production in 2018 were banana, mango, pineapple,
papaya and calamansi. Cotabato Province was the leading producer of banana in the region. For
pineapple, South Cotabato is the top producer in the region. In 2018, the province produced
767,186.77 metric tons of pineapple, which accounted for 35.70 percent of the region's production.
Sarangani was next with 16,820.00 metric tons (down by 11.93 percent) from 19,100 metric tons,
Cotabato with 14,301.82 metric tons (up by 7.33 percent) and Sultan Kudarat with 9,718.70 metric
tons (up by 216.57 percent compared to the same period in 2017 (Philippine Statistics Authority,
2019).

Seasonal Availability of Pineapple

FRUIT MATURITY INDICES

Pineapple fruit should be harvested when it is firm and mature. Pineapples do not improve in eating
quality after harvest. Sugar content does not increase after harvest. Therefore, the fruit must be
picked at the optimum maturity and ripeness stage to suit the intended market. Pineapples
are judged mature when they have reached full size and a nice yellow colour, depending on
variety. There is no single fool proof indicator of pineapple fruit maturity. However, several
external and internal fruit characteristics can be used in combination as indices to determine
harvest maturity (Figure 3). The external indices include fruit surface colour (in most cultivars),
the extent of fruitlet (eye) flatness, and fruit size. The internal indices include percentage soluble
solids (i.e. sugar content) and appearance. The amount of fruit surface yellowing may be used as a
guide for determining when to harvest in certain cultivars. Generally, the more yellow the surface
area (less chlorophyll), the more mature and ripe the fruit. The natural progression of surface
colour change during pineapple fruit maturation is from green to yellow to reddish-brown. If the
fruit is allowed to remain on the plant until the full yellow stage it will have a flatter, less
desirable flavour due to excess sugar content coupled with decreased acidity. The fruit will also be
more susceptible to bruise damage at the full yellow stage. At very advanced stages of over-maturity,
the surface colour of the fruit changes to reddish-brown. Once the fruit has been harvested, the
change in surface colour and amount of yellowing should not be used as an indicator of fruit ripeness,
since postharvest colour changes are not correlated with eating quality.
Colour stages are categorised as follows.
CS1: all eyes green, no traces of yellow;
CS2: 5 to 20% of the eyes yellow;
CS3: 20 to 40% of the eyes yellow;
CS4: 40 to 80% of the eyes yellow;
CS5: 90% of eyes yellow, 5 to 20% reddish brown;
CS6: 20 to 100% of eyes reddish brown.
The pineapple is a compound fruit comprised of numerous individual fruitlets. The fruitlets
mature progressively from the bottom part of the fruit to the top. As the fruitlets mature, they
become flatter. The extent of fruitlet flatness is usually a good indicator of overall fruit
maturity. The bottom fruitlets are much flatter (and riper) than the top ones. Fruit which is
ready for harvest should reach the appropriate size indicative of the cultivar. This is largely
based on previous growing experience. However, individual fruit size by itself is not a reliable index
of harvest maturity. It should be used in addition to surface colour and fruitlet flatness. Fruit
maturity is highly correlated with soluble solids content. Pineapple fruit should have a minimum
of 12% soluble solids near the base and 10% near the top. This is determined by taking two
cross sections of the fruit; one at the point of its largest diameter near the base and another in the
upper third portion of the fruit, and squeezing a few drops of juice from each cross section onto
the prism of a hand-held refractometer. However, this is a destructive test of harvest maturity. It is
used mostly in large-scale operations where sacrificing fruit of different sizes is acceptable in order
to determine the correlation between fruit size and maturity. The internal appearance of the
flesh is also indicative of fruit maturity. Random samples of fruit should be sliced horizontally at
the point of the largest diameter. Immature fruit has a white flesh colour, while mature or ripe
fruit has a yellowish-white flesh. The flesh also becomes slightly translucent in appearance at
maturity. Fruits are over mature when more than half of the cross-sectional area of the fruit is
translucent (Joy & Rajuva, 2016)

Pre-harvest ethylene treatment

Ethrel (Ethephon), has been used as a source of ethylene for decades and it is used to initiate
flowering in pineapples. It has also been applied just before harvesting to accelerate
degreening and therefore the development of the orange colour in the skin. In Queensland,
Smooth Cayenne pineapples treated prior to harvest with Ethrel, at a concentration of 2.5 l in 1000 l
of water, had superior eating quality, degreened more evenly, but had a shorter shelf-life due to
accelerated skin senescence than untreated fruit 10 days after harvest. Treated fruit left on the plant
for 23 days had inferior eating quality to the untreated fruit. These effects are due to the effect of the
ethylene speeding up the maturation of the fruit (Joy & Rajuva, 2016).

Cleaning
Pineapple fruits are quite perishable and should ideally be packed for market within a day of
harvest. The initial step in preparation for market involves cleaning of the outside of the fruit
(Figure 12). For the domestic market, this generally involves trimming of the stem at the base of
the fruit to a length of 1-2 cm, removing any damaged or unsightly leaves in the crown, and a
gentle dry brushing of the fruit surface to remove dirt and dust. A similar protocol should be
followed for the export market, with more emphasis placed on fruit uniformity and quality.
Depending on the xport market requirements, all fruits which are undersized, oversized, over
ripe, under-ripe, damaged, bruised, or show fungal or insect damage should be discarded. The
stem must be trimmed very close to the base and the crown has to be cut back to a length of 10 cm.
Then the fruit has to be washed in a soap solution and thoroughly scrubbed on the outside with a
brush to remove all live insects. The wash water should be properly chlorinated (150 ppm free
chlorine) and maintained at a pH of between 6.5 to 7.0. In addition, an approved postharvest
fungicide should be added to the wash solution to reduce decay. Bayleton and benomyl are two
postharvest fungicides commonly used. After washing, the fruit must be dried and inspected by a
trained and certified inspector. Fruit approved for export by the inspector can then be packed
(Joy & Rajuva, 2016).

Waxing
For maximum potential shelf life, pineapple fruit should be waxed after cleaning and drying.
Several types of food-grade waxes are appropriate for pineapples, and they can be applied by
dipping or spraying. The most commonly used waxes for pineapples are mixtures of carnauba and
paraffin or polyethylene and paraffin. The type of wax chosen must be approved by the
importing country, if the market destination is for export. The wax should be applied only to the fruit
surface and not the crown, as many waxes cause injury to the crown. Beneficial effects of waxing
include a reduction in fruit internal browning, less moisture loss, and a shinier external appearance
(Joy & Rajuva, 2016).

Sorting

Regardless of the market destination, the fruit should be sorted according to size, shape,
firmness, external colour, insect damage, and decay. Visibly damaged fruit should be rejected.
Different markets have different quality requirements and the fruit should be graded to
conform to the individual market standards. However, there are certain minimal requirements for
pineapple fruit intended for any market. The fruit should: be clean and free of dirt or stains be
mature and firm be well shaped and have fully developed eyes (fruitlets) be free of punctures,
wounds, and cuts be free of sunburn, insect damage and decay have a well cured butt have a single
crown (Joy & Rajuva, 2016).

METHODS OF PRESERVATION
Acids, salts and sugars are the principal food preservatives of chemical nature. Sodium chloride (salt)
is perhaps the oldest compound serving as a preservative. Acetic acid in the form of vinegar is
used in the manufacture of several pickled products. Benzoic acid, sodium salts - sodium
propionate, di acetate and sulphur dioxide, and sodium chloride are added to foods to prevent
spoilage. Sugars are employed in the manufacture of jelly, jams, preserves, sweetened condensed
milk, sweet pickles and other products aiding the preservation of the products into which they are
incorporated (Joy & Rajuva, 2016).
Preservation by sugar
Sugar is generally added in the processing of jams, jellies and sweets. The fruit must be boiled, after
which the sugar is added in variable amounts, depending upon the kind of fruit and the product
being prepared. The mixture must then continue to boil until it reaches a high level of soluble solids,
which allows for its preservation. The addition of sugar combines with certain fruit substances to
produce a gel like consistency, which characterizes the texture of jams and jellies. To achieve this,
appropriate acidity levels and sugar content, together with pectin must be used, form a proper gel
(Joy & Rajuva, 2016).

STORAGE CONDITIONS

Temperature

For maximum postharvest life, pineapple fruit should be cooled to 8°C as soon as possible after
harvest and maintained at this temperature during transport to market. At this temperature,
pineapples harvested at the quarter-yellow stage have a shelf life of approximately 3 weeks.
Storage at higher temperatures will result in reduced shelf life, to as short as only a few days at
ambient temperature (30-32°C). Fruits that are quarter yellow at harvest, gain about four
additional days of shelf life for every 6°C decrease in storage temperature from 32° to 8°C. On the
other hand, pineapple fruits are subject to low temperature breakdown, also known as chilling
injury, and should not be stored below 8°C. Sensitivity to chilling injury is related to the ripeness
stage of the fruit, with mature green fruit being more susceptible. Internal tissue darkening and
postharvest decay are typical symptoms of chilling injury. Pineapples harvested at more advanced
stages of ripeness will have short market life. For example, fruit harvested at the half-yellow
colour stage will have about 10 days of storage life at 8°C followed by an additional week of market
life (Joy & Rajuva, 2016).

Relative Humidity

Pineapple fruits are susceptible to wilting, shrinking and shrivelling in low relative humidity (RH)
storage environments. Most of the weight loss occurs through the leaves of the crown. The rate of
transpiration and water loss from the fruit becomes increasingly greater with decreasing RH. Ideally,
pineapples should be held at 90 to 95% RH (Joy & Rajuva, 2016).

PROCESSING OF PINEAPPLE

There is a series of physical properties of pineapples that play important roles during
processing. It was found that in addition to be considered as a maturity index, translucency is a quality
attribute of the fruit. Translucent or semi translucent slices are generally considered as desirable and
associated with better flavour. Fully translucent pulp has an overripe flavour, while those not
translucent are too sour. As pulp becomes more translucent air cavities decrease in size and
therefore porosity. Internal colour affects the appearance and acceptance of the fruit; yellow-gold
colour has been regarded as best. It is not merely to satisfy producers and processors by way of
higher monitory return but also with better taste and nutrition. According to the Food and
Agricultural Organisation's (FAO) definition, processed foods can be of three types: primary,
secondary and tertiary. Primary processed foods involve basic cleaning, grading and packaging.
Secondary processing means modification of the basic product to a stage just before the final
preparation at the consumer's kitchen. Tertiary processing leads to high value-added ready-to-eat
products like ice cream, jams, jellies etc. (Joy & Rajuva, 2016).

Dehydrated products

It is a simpler method of processing and extension of storage life by physical removal of water, by hot
air drying, which is economical on commercial scale. Here the fresh material is dried to residual
moisture of about 5% and depending upon the required retention of pigmentation, flavour and
taste. The dried material can be rehydrated using water. The storage life of dried material can be
of six months at room temperature. This process offers the scope for reduction in bulk and due to the
light weight reduces freight charges. Osmodehydrated and intermediate moisture products of 25%
water content merit direct consumption without the need for reconstitution. Pineapple has been
known to be excellent for drying. In this product, most of the free water of the fruit is eliminated. To
prepare, select fully ripe, fresh pineapple. Remove skin and eyes from pineapple with a sharp knife.
Usually, chunks or slices are prepared for better presentation and make handling easier. Final
moisture is near 5%, and this allows the dried fruit to have a long shelf life as long as proper packing
is provided and storage is done in a fresh place (Joy & Rajuva, 2016).

Osmosis

Osmosis is the spontaneous net movement of water through a semipermeable membrane from a
region of low solute concentration to a solution with a high solute concentration, up a solute
concentration gradient. It is a physical process in which a solvent moves, without input of energy,
across a semi permeable membrane (permeable to the solvent, but not the solute) separating two
solutions of different concentrations. Osmosis is important in biological systems as many biological
membranes are semipermeable. In general, these membranes are impermeable to organic solutes
with large molecules, such as polysaccharides, while permeable to water and small, uncharged
solutes.

https://www.chemeurope.com/en/encyclopedia/Osmosis.html#_note-0/

Osmotic Dehydration

Osmotic dehydration (OD) is an intermediate drying process in which water containing food materials
are submerged in a hypertonic solution of salt or sugar or salt-sugar mixtures. Cellular membranes of
food tissues are semi-permeable in nature and are composed of living biological units that freely allow
solvent (i.e. water) molecules to pass through, but allow the passage of solute molecules to a lesser
degree (Khin et al., 2007). The driving force for water removal is difference in osmotic pressure
between the plant tissue and its surrounding solution (Jokic et al., 2007). During osmotic dehydration,
water flows from the plant tissue into the osmotic solution whereas osmotic solute diffuses from the
solution to the tissue. Simultaneously, leaching of tissue’s own solutes (sugars, organic acids,
minerals, vitamins, etc.) into the osmotic solution occurs as well, but to a much lesser extent
compared to the first two transfers. Therefore it is a multi-component process (Sagar et al., 2010).
Osmotic dehydration lowers the water activity of fruits and vegetables thereby extending their shelf
life. Osmotic dehydration is preferred over other methods due to their color, aroma, nutritional
constituents and flavour compound retention property (Yadav & Singh, 2012). The solutes commonly
used in osmotic dehydration are sugar syrup with fruit slices or cubes and salt (sodium chloride) or
brine with vegetables. Osmotic dehydration is affected by several factors such as osmotic agent,
solute concentration, temperature, time, size, and shape and tissue compactness of the material,
agitation and solution/sample ratio (Pandharipande et al., 2012).

https://chesci.com/wp-content/uploads/2020/06/15_CS20510178_p337-341.pdf

The osmotic dehydration process is long and often requires the acceleration of mass transfer using
traditional and innovative methods. OD process allows obtaining semidried products with improved
stability, thanks to the reduction of their water activity and freezable water content. OD treatment
can be applied at room temperature or at temperatures which are slightly higher in order to increase
a mass transfer rate, however usually it does not exceed the temperature of 40–45 ◦C. Traditionally,
agitation and rotation are used for this purpose. However, OD, especially when applied at room
temperature, is a time-requiring process, therefore recently the combination of OD with other
traditional and innovative techniques has been studied. These combined treatments include the
application of ultrasound, pulsed electric field, high hydrostatic pressure, vacuum, irradiation and
centrifugal force, which are able to increase mass transfer in the treated products (Nowacka et al.,
2021).
2_Current Applications of Ultrasound in Fruit and Vegetables Osmotic Dehydration
Processes_Nowacka et al._2021.pdf

According to Sharma et al. (2003) during osmotic dehydration always water loss is favored over solid
uptake that leads to mass loss of pear fruit. According to their experiment all these parameters
depends on concentration of syrup and syrup to fruit ratio. It was found that with increase in syrup
concentration from 35 to 45 °B and syrup fruit ratio from 1 to 2, there was considerable change in
water loss from 18.09% to 23.18%, mass loss from 9.26% to 20.06% and solid gain from 13.59 to
16.38% (Yadav & Singh, 2012).

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4152536/#:~:text=Osmotic%20dehydration%20is
%20the%20phenomenon,of%20membrane%20(Tiwari%202005).

Bashir et al. (2020) investigated the impact of different drying methods on total sugars and titrable
acidity of tomates. The study reported higher titrable acidity (0.75%) in osmo-air dried tomatoes
indicating lesser damage to vitamin C content of tomatoes in contrast to oven and solar dried
tomatoes reflecting titrable acidity of 0.21 and 0.30 per cent, respectively. Nishadh and Mathai
(2014), carried out studies on osmotic dehydration characteristics of radish in different concentration
of osmotic solutions such as salt (3, 6, 9) percent and sugar (30, 40, 50) ˚Brix. It was observed that in
the case of moisture content and dry matter content, sugar solution is more effective whereas in the
case of rehydration ratio salt solution gave better results. It was concluded that using a combination
of these osmotic agents increases the dehydration effect. The optimum concentration of osmotic
agents at room temperature was found to be 6 per cent for salt solution and 400 ˚brix for sugar
solution. The proximate analysis revealed that moisture content, ash content and ascorbic acid in
osmotic dehydrated radish was found to be less than that of raw radish and higher than the oven
dried radish indicating osmotic dehydration retains the nutritive properties of radish than normal
drying. Lee and Lim (2011), elucidated the effects of osmotic dehydration on pumpkin slice prior to
hot-air drying. In thisstudy Response Surface Methodology (RSM) with Central Composite Design was
used to investigate the influence of three variables, namely sucrose concentration (30-60˚Brix),
immersion temperature (35-65˚C) and immersion time (90-120 min). It was found that these factors
increased the solid gains and decreased the water activity (aw) of the sample while the temperature
and sucrose solution concentration increased the water loss. The process temperature also affected
the sensorial properties by increasing the sweetness, dryness, hardness and overall acceptance of the
dried pumpkin slice. However, increasing temperature caused the deterioration of colour and aroma.
Longer immersion time resulted in increase in shrinkage, sweetness and overall acceptability of the
final product. https://chesci.com/wp-content/uploads/2020/06/15_CS20510178_p337-341.pdf

Principles of osmotic dehydration

Emerging innovative approaches have been thoroughly studied in terms of physico-chemical changes
in the product during the dehydration process. Drying not only protects the product but it can also
improve the quality of the materials which can develop value-added compounds during the drying
process such as spices, medicinal plants, herbs, nuts, fruits and vegetables (Calin-sanchez, 2021).
Alzamora et al., (2005) suggested that osmotic dehydration (osmotic treatment or dewatering
impregnation soaking) appears to be a viable technology for the development of fruits and vegetable
matrices to which functional ingredients can be successfully added, resulting in novel functional
products and new commercial opportunities. The development of intermediate moisture food via
osmotic dehydration has added a lot of attention from consumers in recent years due to its minimal
processing (Ahmed et al., 2016).

Osmotic dehydration is done by immersing foods such as fruits and vegetables in concentrated
soluble solid solutions with higher osmotic pressure and lower water activity. The difference in the
chemical potential of water between the food and the osmotic medium causes dehydration (Shete et
al., 2018). During osmotic dehydration process, tissue shrinkage and mass transfer occur at the same
time (Ahmed et al., 2016). Due to the complicated internal structure of food systems, achieving a full
semi-permeable membrane is challenging and sometimes there is also solid diffusion into the food
meaning that osmotic dehydration is a combination of water and solute diffusion processes (Chandra
& Kumari, 2015).

Bellary & Rastogi (2012) viewed that the major advantage is to reduce the water activity of food
materials, thereby inhibiting the growth of micro-organisms, since most of the food materials consist
large amount of water;they are cost effective to storage and transportation. Osmotic dehydration is
found to be an energy efficient method of partial dehydration process, since phase change is not
needed. Other possibilities include food formulation by lowering the water activity and food
fortification with compounds that can alter its structural, functional and nutritional properties. It is
effective under room temperature so that heat damage to colour, texture, flavour also the loss of
volatile component and oxidative changes could be minimized (Alzamora et al., 2005;Hasanuzzaman
et al., 2014).

4_Recent developments in osmotic dehydration of fruits_Saleena et al._ 2022.pdf

Osmotic agent
Osmotic dehydration is a process that combines dehydration and impregnation to lower the adverse
effects of fresh food components. It is the process of partially reducing water from a substance by
directly contacting it with a hypertonic medium such as a high concentration of sugar or salt solution
for fruits and vegetables (Bellary & Rastogi, 2016).

Ahmed et al., (2016) [18] reported that depending on the final product, many types of osmotic agents
are utilised, such as glucose, corn syrup, sodium chloride, starch concentrates, fructose, and sucrose.
Lopez et al., (2021) pointed out that during osmotic dehydration, the osmotic agent plays a very
important role as they effect the product's sensory and physical attributes. The most prevalent
osmotic agent found in fruits is sucrose. Even though, the polyol solutions like inulin, maltitol, xylitol,
erythritol and oligofructose showed similar or higher productivity as an appropriate substitute to
sucrose solution.
In general, solutions made of sucrose are used to dehydrate fruits and sodium chloride is used to
dehydrate vegetables. The force behind the drying process is increased with the incorporation of
small quantities of sodium chloride to osmotic solution and explained the synergistic effects of sodium
chloride and sucrose (Lerici et al., 1985).

Normally, low molecular weight osmotic agents are more easily absorbed by fruit cells than high
molecular weight osmotic agents. An osmotic agent or multiple osmotic agents can be used to treat
osmotic dehydration. The osmotic agent needs to be practical, reliable, non-toxic, and delicious. It
should be simple to dissolve and affordable to produce a highly concentrated solution that does not
react with the material. Sugar and salt solutions found to be the best options in terms of efficacy,
convenience, and taste (Tortoe, 2010)

During the drying of osmotically treated products, sugar solution limits oxygen access, stabilises
pigments and aids in the retention of volatile components (Pattanapa et al., 2010).
Yadav & Singh (2014) found that a combination of various osmotic agents was more efficient than
sucrose alone.

4_Recent developments in osmotic dehydration of fruits_Saleena et al._ 2022.pdf

Solid Gain

Solid gain (SG) represents the total amount of solid absorbed by the fruits
orvegetables after osmotic dehydration for a certain time. They were expressed on
the basis of initial dry weight of the product. A high solid gain means a high product
yield which is desirable for many commercial applications Shi et al. (2007). Sucrose
concentration, temperature and solution to sample ratio were the factors cited to
directly affect the solid gain of fruits and vegetables during osmotic dehydration
(Khoyi & Hesari, 2007).
Thesis TURMERIC

Sensory evaluation
Sensory evaluation is an essential component of a food research project or product
development. The Sensory Division of the Institute of Food Technologists (IFT,
1981b) defines sensory evaluation as “A scientific discipline used to evoke, measure,
analyze, and interpret reactions to those characteristics of foods and materials as
they are perceived by the senses of sight, smell, taste, touch, and hearing.” Sensory
evaluation tests may be used in product development, research, quality control, and
shelf-life studies. In each of these applications, sensory evaluation data may be used
as the basis for decision-making. Several factors must be controlled in conducting a
sensory evaluation test to minimize experimental error in the data.
https://www.sciencedirect.com/book/9780121579203/experimental-food-science

Sensory evaluation gathers methods that aim at measuring consumers’ sensory

perception of products as well as affective, emotional, and behavioral responses that
arise from this perception. In the industry, it applies to quality control, product
development, and market research. For that purpose, sensory evaluation uses a
broad range of techniques that derive from psychophysics and from social and
behavioral sciences. Sensory evaluation thus represents a true science of
measurement. In nonfood industries, some would also refer to “sensory metrology”
(D’Olivo et al., 2013).
https://www.sciencedirect.com/science/article/abs/pii/B9780128219393000208

Sensory evaluation plays a major role not only in the quality control of manufactured
products, but also in the development of new products. To perform sensory
evaluations, the opinion of people with different levels of training and experience is
sought. One level of evaluators are untrained people, such as customers in a
supermarket, who are given samples of food and are asked either for their “overall”
impression or to describe what they like or dislike about the food that they are
tasting. Another type of evaluator are people who have had some specific training in
sensorial evaluation of food. Finally, there are professional evaluators who are highly
trained specialists, who over time quite often develop an exceptional knowledge of
products in terms of their desired texture, consistency, and visual appearance as well
as flavor and taste. To perform a sensory evaluation correctly requires knowledge of
statistical mathematics and matters such as correlations, levels of reliability, and
levels of significance have to be taken into account.
https://www.sciencedirect.com/science/article/abs/pii/B9781845690502500368

Ultrasound assisted osmotic dehydration

Many researchers has shown interest on ultrasound usage in the osmotic process
because it can be used as a pre-treatment or as an ultrasound assisted osmotic
dehydration (Małgorzata et al., 2021) [61]. Li et al., (2020) [62] pointed out that
ultrasound has long been utilised as a pre-treatment for the drying of fruits and
vegetables. Ultrasound waves can generate a series of alternate compressions and
expansions in connection with osmotic dehydration moreover low frequency
ultrasound waves found to be appropriate for fruits and vegetables. The sonication
effect creates bubbles in the osmotic solution. It has the potential to explode and
create localised pressure that may facilitate in the removal of the water content of
fruits and vegetables (Ahmad & Zaidi, 2020) [63].

Rahaman et al., (2019) [64] investigated the application of ultrasound during osmotic
dehydration using 50% glucose and sucrose for 30 and 60 min enhances water loss
and solid gain in the plum. Another study on ultrasound based osmotic treatment of
kiwi fruit was reported by (Prithani & Dash, 2020) [65]

To produce a stable intermediate moisture product with appreciable nutrient

composition and sensory qualities, a combination of ultrasound pre-treatment and
osmotic dehydration could be utilised and the product can be used itself as a dried
fruit or as an addition with other processed food products.

CLASSIFICATION OF ULTRASOUND APPLICATION

Nowadays, ultrasound is an attractive subject in the food industry. Industries can use
practically ultrasonic equipments and it is known as green novel technology due to
its role in the environment sustainability. Methods of ultrasound applications can be
divided into three: 1) Direct application to the product, 2) Coupling with the device,
3) Submergence in an ultrasonic bath [3]. Also, ultrasonic applications in the food
industry are divided into two distinct categories according to the energy generated
by sound field. These are low and high energy ultrasounds which are classified by
their sound power (W), sound energy density (Ws/m3) and sound intensity (W/m2).
Low energy (low power, low-intensity) ultrasound applications are performed at
frequencies higher than 100 kHz and below 1 W/cm2 intensities. Small power level is
used for low intensity ultrasound so that it is nondestructive and no change occurs in
the physical or chemical properties of food. Low intensity ultrasound in the food
industry is generally used for analytical applications to get information about the
physicochemical properties of foods such as composition, structure and physical
state [8-10].High energy (high power, high-intensity) ultrasounic applications are
performed generally at frequencies between 18 and 100 kHz and are intensities
higher than 1 W/cm2 (typically in the range 10 - 1000 W/cm2) [10]. At this power,
destruction can be observed due to the physical, mechanical or chemical effects of
ultrasonic waves (e.g. physical disruption, acceleration of certain chemical reactions).
High-intensity ultrasound has been used for many years to generate emulsions,
disrupt cells and disperse aggregated materials. More recently it is used for many
purposes such as modification and control of crystallization processes, degassing of
liquid foods, enzyme inactivation, enhanced drying and filtration and the induction
of oxidation reactions [9,11].
https://www.scirp.org/html/2-8302129_35845.htm
METHODS OF ULTRASOUND
Ultrasound can be used for food preservation in combination with other treatments
by improving its inactivation efficacy. There have been many studies combining
ultrasound with either pressure, temperature, or pressure and temperature.

1) Ultrasonication (US) is the application of ultrasound at low temperature.

Therefore, it can be used for the heat sensible products. However, it requires long
treatment time to inactivate stable enzymes and/or microorganisms which may
cause high energy requirement. During ultrasound application there may be rise in
temperature depending on the ultrasonic power and time of application and needs
control to optimize the process (Zheng and Sun, 2006).

2) Thermosonication (TS) is a combined method of ultrasound and heat. The product

is subjected to ultrasound and moderate heat simultaneously. This method produces
a greater effect on inactivation of microorganisms than heat alone. When
thermosonication is used for pasteurization or sterilization purpose, lower process
temperatures and processing times are required to achieve the same lethality values
as with conventional processes (Mason, Paniwnyk & Lorimer, 1996; Villamiel,
Hamersveld, & De Jong, 1999).

3) Manosonication (MS) is a combined method in which ultrasound and pressure are

applied together. Manosonication provides to inactivate enzymes and/or
microorganisms by combining ultrasound with moderate pressures at low
temperatures. Its inactivation efficiency is higher than ultrasound alone at the same
temperature.

4) Manothermosonication (MTS) is a combined method of heat, ultrasound and

pressure. MTS treatments inactivate several enzymes at lower temperatures and/or
in a shorter time than thermal treatments at the same temperatures (Chemat et al.,
2011). Applied temperature and pressure maximizes the cavitation or bubble
implosion in the media which increase the level of inactivation. Microorganisms that
have high thermotolerance can be inactivated by manothermosonication. Also some
thermoresistant enzymes, such as lipoxygenase, peroxidase and polyphenoloxidase,
and heat labile lipases and proteases from Pseudomonas can be inactivated by
manothermosonication (Manas et al., 2006).

https://www.scirp.org/html/2-8302129_35845.htm

Drying rate
Drying temperature

Use of sugar in osmotic dehydration

Sugar is one of the oldest additives used in preserving foods. Most preserved fruits
and vegetables are treated with sugar in order to enhance or maintain their
sweetness. Canned fruits are examples of both soaking and storage solutions not
only to maintain the quality of products but also to enhance the sweetness (Camire,
2000). Dehydrated fruits such as dried apples, grapes, and peaches are also pre-
treated with sugar to impact a sweet flavor (Caballero, 2003). Since pineapple is
naturally sweet, the use of sugar is presumed to be more acceptable than salt. In
addition to the attribute of sweetness, sugar has other benefits regarding the
physical and chemical properties of foods. Ponting, 1973 suggested that sugar is an
effective inhibitor of polyphenol oxidase (PPO) and prevents the loss of volatile
compounds during dehydration. In physical properties, Fito, et. al. (2001) and Raoult-
Wack, Rios, Saruel, & Guilbert (1994) have indicated the usage of sugar decreases
the compression of pore size in cellular matrix and improves texture and stability of
pigments during the drying process of osmotic dehydration. In osmotic dehydration,
the sugar soaking solution is able to strength cell walls, resulting in firmer fruits
texture while the storage period (Camire, 2000).

JAYSON-COLE-OD-OF-WATERMELON.pdf

Ultrasound

Ultrasound is a form of energy generated by sound (really pressure) waves of

frequencies that are too high to be detected by human ear, i.e. above 16 kHz
[Jayasooriya et al. 2004].

https://www.food.actapol.net/pub/8_3_2007.pdf

Developments in the application of ultrasound in processing began in the years

preceding the Second World War when it was being investigated for a range of
technologies including emulsification and surface cleaning. By the 1960s the
industrial uses of power ultrasound were accepted and being used in cleaning and
plastic welding which continue to be major applications [Mason 2003].
https://www.food.actapol.net/pub/8_3_2007.pdf

The US waves of low intensity and high frequency are used for diagnostic purposes,
mainly in medicine and industry, including food industry. These waves do not cause
physical and chemical changes in the material they go through, which allows for their
application in non-invasive analytical techniques (Bromberger Soquetta et al., 2018).
High intensity US causes irreversible changes in the structure of the material and
thus is used to accelerate the heat and mass transfer processes in the food industry
as well as in cleaning machines. High intensity US causes physical changes to the
material, including its damage, as well as the initiation of various chemical reactions,
including oxidation processes. It can also be successfully used to isolate intracellular
proteins, for food preservation and to inactivate or activate enzymes. Thus, this
paper focuses only on the high intensity US.
Generally, US can be applied as a pretreatment or treatment during process
(USassisted process) by the means of various devices and methods (immersive,
contact or airborne US). Immersive method is most commonly used to accelerate OD
both before (US as a pretreatment) and during OD, as well as for further drying
(Nowacka et al., 2021).
2_Current Applications of Ultrasound in Fruit and Vegetables Osmotic
Dehydration Processes_Nowacka et al._2021.pdf