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Approaches for delivery of heat sensitive nutrients through food systems for selection of appropriate processing techniques: A review


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Food contains many heat sensitive nutrients which include vitamins, minerals, and nutrients having functional properties such as pigments, antioxidant, Bioactive compounds. Many processes during manufacturing of food cause detrimental effects on these nutrients. Retention of these nutrients in food products requires innovative approaches for process design because of their sensitivity to a variety of physical and chemical factors, which causes either loss of biological functionality, chemical degradation and premature or incomplete release. This article reviews effect of Different Processes on Heat Sensitive Nutrients and approach for selecting appropriate processing technology. Proposed target application of nutrient is first analyzed using scientific principles, including materials science, physical chemistry and biophysics. The scientific understanding is used to develop a range of potential solution strategies from which the most feasible is selected for further development. Based on technological considerations, such as cost, ease of manufacturing, adaptability, one of these various possible solutions is finally implemented in the actual food product. The major advantage of Retro-design approach is that it does not focus from the outset on a specific technology. Application of Sensitive Nutrient is placed at the centre and from there systematically works back to find a feasible technology to introduce or retain sensitive nutrient in the food product. A wide selection of delivery systems is available for the use in food systems. Ultimately, one would like to relate the characteristics of the delivery systems to the functional attributes of the final product, such as sensory, physico-chemical and biological nutritional impact. Studies have shown that use of Novel Thermal as well as Non-thermal processing techniques such as Pulsed X-ray Processing, Oscillating Magnetic Fields, Low-Temperature Plasma, Ozone processing, Dense-Phase Carbon Dioxide Processing of Fluid Foods, Ultra-sound Processing of Food, High Voltage Arc for better retention of Sensitive nutrients.
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Journal of Hygienic Engineering and Design
Review paper
UDC 664:612.39
Mahesh Satpute1*, Uday Annapure1
1Food Engineering and Technology Department, Institute of Chemical Technology, Nathalal
Parikh Marg, Matunga (E), Mumbai - 400019, India
Food contains many heat sensitive nutrients which
include vitamins, minerals, and nutrients having
functional properties such as pigments, antioxidant,
Bioactive compounds. Many processes during man-
ufacturing of food cause detrimental eects on these
nutrients. Retention of these nutrients in food prod-
ucts requires innovative approaches for process design
because of their sensitivity to a variety of physical and
chemical factors, which causes either loss of biological
functionality, chemical degradation and premature or
incomplete release.
This article reviews eect of Dierent Processes on Heat
Sensitive Nutrients and approach for selecting appro-
priate processing technology. Proposed target appli-
cation of nutrient is rst analyzed using scientic prin-
ciples, including materials science, physical chemistry
and biophysics. The scientic understanding is used to
develop a range of potential solution strategies from
which the most feasible is selected for further develop-
ment. Based on technological considerations, such as
cost, ease of manufacturing, adaptability, one of these
various possible solutions is nally implemented in the
actual food product.
The major advantage of Retro-design approach is that
it does not focus from the outset on a specic technol-
ogy. Application of Sensitive Nutrient is placed at the
centre and from there systematically works back to nd
a feasible technology to introduce or retain sensitive
nutrient in the food product.
A wide selection of delivery systems is available for the
use in food systems. Ultimately, one would like to relate
the characteristics of the delivery systems to the func-
tional attributes of the nal product, such as sensory,
physico-chemical and biological nutritional impact.
Studies have shown that use of Novel Thermal as well
as Non-thermal processing techniques such as Pulsed
X-ray Processing, Oscillating Magnetic Fields, Low-
Temperature Plasma, Ozone processing, Dense-Phase
Carbon Dioxide Processing of Fluid Foods, Ultra-sound
Processing of Food, High Voltage Arc for better reten-
tion of Sensitive nutrients.
Key words: Nutrient delivery system, Food system, Heat
sensitive nutrients, Retro-design approach, Processing
impact, Non-thermal processing techniques.
1. Introduction
1.1 Eect of processing on nutrients
1.1.1 Nutrients directly aected by heat treatments
Food contains many heat sensitive nutrients which
include vitamins, minerals, and nutrients having func-
tional properties. Vitamins are organic components in
food that are needed in very small amounts for growth
and for maintaining good health. The vitamins include
vitamin D, E, A and K (fat-soluble vitamins), and folate,
vitamin B12, biotin, vitamin B6, niacin, thiamin, riboa-
vin, pantothenic acid, and vitamin C (water-soluble vi-
tamins). Vitamins are required in the diet in only tiny
amounts, in contrast to the energy components of the
diet. Many processes during manufacturing of food
cause detrimental eects on these nutrients. Maximum
destruction during heat processes is of vitamin and
minerals. Vitamins are unstable in foods. Processing
and cooking conditions cause vitamin loss. The losses
vary widely according to processing method and type
of food. Vitamin degradation depends on specic pa-
rameters during the culinary process, e.g., temperature,
oxygen, light, moisture, pH, and obviously length of ex-
posure. Vitamin A is stable under an inert atmosphere;
however, it rapidly loses its activity when heated in the
presence of oxygen, especially at higher temperatures.
Carotenoids are extremely susceptible to degradation.
Their highly unsaturated structure makes them sensi-
tive to heat, oxygen, and light [1 and [2]. Vitamin D is
Journal of Hygienic Engineering and Design
susceptible to the alkaline pH range, light, and heat
[3 and 4]. However, fat content is probably the crucial
factor aecting retention during culinary treatment.
A high-fat content usually results in a high vitamin D
loss due to dripping o, while low-fat content might
probably disrupt thermal isolation and vitamin D is
more easy accessible to other aggressors (e.g., light).
Retention of vitamin D varied in the range of 60–90%
during culinary treatment of meat and sh [5].
In case of vitamin E most common heat treatments, such
as broiling or roasting, cause a high loss of the nutrient.
The vitamin E content in food treated in vegetable oil
increases or remains stable because vegetable oils are
a good source of the fat-soluble vitamin. Vitamin E is
unstable in the presence of reducing agents: oxygen,
light, and peroxides (occurring as a result of unsaturat-
ed fat auto-oxidation). Retention of vitamin E is in the
range of 44–95% during culinary treatment of various
types of meat, and 60 - 93% in the case of legumes.
Vitamin K shows stability during culinary treatment
combined with sucient human intake of this nutrient
world-wide. Cooking losses of L-ascorbic acid depend
on the degree of heating, leaching into the cooking
medium, surface area exposed to water and oxygen,
pH, presence of transition metals, and any other factors
that facilitate oxidation [6]. Higher retention values
were often observed in vegetables prepared by steam-
ing (up to 99%), microwave steaming and stir-frying
with oil, followed by stir-frying with water, and nally
by boiling which caused the most extensive damage,
with losses of up to 75%. Losses of AA are minimal
when vegetables are cooked without any water, while
maximum losses are associated with cooking in a large
amount of water and oxygen present [5].
Thiamine is highly unstable at alkaline pH. Stability de-
pends on the extent of heating and on the food matrix
properties. Thermal degradation occurs even under
slightly acid conditions. Thiamine is highly unstable at
alkaline pH. Stability depends on the extent of heat-
ing and on the food matrix properties. Thermal deg-
radation occurs even under slightly acid conditions.
Thiamine is more sensitive to heat than is riboavin [6].
Riboavin is stable with respect to both oxidation and
heat, but sensitive to light [7]. Riboavin is very resis-
tant to dry heat, acid solutions, and air (oxygen), but
very sensitive to light, especially at high temperatures
and pH values. During cooking riboavin leaches into
water. Among the heat treatments and vegetables
mentioned, the highest losses (up to 66%) were ob-
served in cabbage. Folate losses during cooking and
preparation are the result of a combination of thermal
degradation and leaching of the vitamin into the cook-
ing water [6].
Folate is sensitive to sunlight, air, and light and being
heated in acid solutions. Folate is lost in food during
cooking because it breaks down under heat and leach-
es into the cooking water. The presence of reducing
agents (AA) in the food can increase folate retention
during thermal processing. Folates of animal origin ap-
peared to be stable during boiling and frying.
Pantothenic acid is the most stable vitamin during
thermal processing with pH levels of 5 - 7. Large losses
can occur through leaching into cooking water during
preparation of vegetables. Niacin is the most stable
water-soluble vitamin. Processing and cooking proce-
dures do not deactivate niacin. Leaching is usually the
primary pathway of its loss during food preparation [6].
Retention of niacin is in the range of 45 - 90% within
the various culinary treatments of meat and legumes.
Thermal degradation of vitamin B6 increases as pH
rises. Vitamin B6 is resistant to heat, acid, and alkaline,
but sensitive to light in neutral and alkaline solutions.
Pyridoxal and pyridoxamine are more heat, oxygen,
and light labile than pyridoxine (the primary vitamer in
Vitamin B12 is generally considered to be stable under
most food processing operations, but like all water-sol-
uble vitamins, it is subject to large losses through
leaching into the cooking water. Vitamin B12 is normally
stable during pasteurization of milk, but up to 20% can
be lost during sterilization [8].
Biotin is stable when heated in the presence of light
and in neutral or even in strong acid solutions, but it is
labile in alkaline solutions. In general, biotin retention
is relatively high during heat treatment (80% in meat,
85–90% in milk pasteurization, 85–95% in legumes,
70% in preservation of fruits and vegetables) [5].
1.1.2 Nutrients became unavailable during heat
Minerals are the inorganic elements, as calcium, iron,
magnesium, potassium, or sodium, that are essential to
the functioning of the human body and are obtained
from foods. Minerals also get aected by heat treat-
ment during processing. The study of processing im-
pact on the fate of minerals is modelled after the analy-
sis of vitamin or macronutrient loss during processing.
Since ash values (determined before and after process-
ing) do not drastically change, minerals seemed not
to be aected during food processing. The late Robert
Harris has summarised the maximum losses of minerals
during cooking to be not larger, on average, than 3%.
However, the classical nutritional evaluation of food
processing by global estimation of mass losses might
be misleading in the assessment of processing impact
on bioavailability [9].
It might be possible that minerals were not lost during
processing, but combined with co-nutrients or non-
food components. They may become unavailable for
Journal of Hygienic Engineering and Design
digestion due to these interactions. Moreover, the op-
posite eect may also occur: increased bioavailability
because of destruction of binding ligands (e.g. phy-
tates). Various review articles have focused on the mass
losses in unit operations, mostly concerned with the
losses of Ca, Zn and Fe [9].
Hazell and Johnson [10], proposed that the reaction
products of depolymerisation processes under the
high temperature and shear might change the chemi-
cal form of iron and make it more soluble which increas-
es its availability. There were no established changes in
the bioavailability of zinc and iron [11].
Since the inorganic and organic forms of metal ion
complexes can have dierent absorbability, knowl-
edge of the chemical form is pre-eminent for the un-
derstanding of the physiological impact of the mineral.
For example, it was shown that peptides liberated by
the digestion of meat enhance the bioavailability of
the soluble iron in the intestinal lumen [12]. Results of
interaction of minerals with unit processes are sum-
marised below [13].
Table1. Eect of heat treatments on minerals
Processing Possible causes of losses or gains
Boiling/Cooking Leaching oxidative losses phytate
Blanching HCl extractability of Zn and Ca
steaming Few losses
Canning Complex destruction
Baking Phytate hydrolysis increase absorption
Frying Iodine losses
Drying Denaturation of binding proteins,
Maillard reaction
Fermentation Phytate content reduction, hydrolysis
Extrusion Phytase deactivation eects
Too much water, no use of cooking
water (pasta 20%, veg. 15%) reduces
mineral bioavailibity
1.1.3 Nutrients having functional properties
This comprises wide range of bioactive compounds
such as pigments, antioxidant, and immune boosting
naturally occurring bioactive compounds. Volden [14]
reported that blanching, boiling and steaming resulted
in losses of 59%, 41% and 29% respectively in anthocy-
anin content of red cabbage. Curcumin loss from heat
processing of turmeric was 27–53%, with maximum
loss in pressure cooking for 10 min. Curcumin loss from
turmeric was similar even in the presence of red gram.
In the presence of tamarind, the loss of Curcumin from
turmeric was 12–30%. Capsaicin losses from red pep-
per ranged from 18% to 36%, with maximum loss ob-
served in pressure cooking. Presence of either red gram
or tamarind or both did not inuence the loss of cap-
saicin. Piperine losses from black pepper ranged from
16% to 34%, with maximum loss observed in pressure
cooking [15].
2. Nutrient Delivery Systems - Basics
The creation of novel functionality of heat sensitive
nutrients in complex food materials is of increasing im-
portance for the food scientists. Application of active
ingredients in food products often requires innovative
approaches because of their sensitivity to a variety of
physical and chemical factors, which causes either the
loss of biological functionality, chemical degradation
or a premature or incomplete release. The situation is
challenging not only because of the high sensitivity
to temperature, but also because of the complexity of
many food products and the conditions prevalent in
many food matrices. In addition, product safety, ap-
pearance, storage conditions, ease of preparation by
the consumer, freshness and sensory properties of the
food product are not to be compromised by the incor-
poration of the heat sensitive nutrients.
Job Ubbink and Jessica Kruger [16] proposed target
application rst analyzed using scientic principles, in-
cluding materials science, physical chemistry and bio-
physics. The scientic understanding is used to develop
a range of potential solution strategies from which the
most promising may be selected for further develop-
ment. Based on technological considerations, such as
cost, ease of manufacturing, adaptability, one of these
various possible solutions may nally be implemented
in the actual food product. The major advantage of this
approach is that it does not focus from the outset on a
specic technology to solve an issue, which might be
poorly understood, and for which the selected technol-
ogy may ultimately be ineective.
In a retro-design approach to the delivery of heat sen-
sitive nutrients, the food application is placed at the
centre and from there one systematically works back
to nd a feasible technology to introduce the sensitive
nutrient in the food product. The principle of retro-de-
sign, as developed in organic synthesis, allows the sys-
tematic evaluation of all steps and routes starting from
the nal product down to the raw materials. In organic
chemistry, such a retro-design allows the evaluation of
all possible reaction pathways and intermediates lead-
ing to the desired product and facilitates the choice of
the favoured synthesis route based on a rational com-
promise between reaction yields, number of reaction
steps, and availability of starting materials. In addition,
the approach has proved useful as it allows the deni-
Journal of Hygienic Engineering and Design
tion of chemical transformations which do not yet exist
but whose development may then be attempted [17].
Figure 1. Flow diagram for retro-design approach
application for food application
In the food eld, application of this approach is very
useful, in particular in the development of complex
food products containing active ingredients. In adopt-
ing a retro-design approach towards the delivery of
sensitive nutrients in foods, one starts by dening pre-
cisely the functionality and performance of the active
ingredient desired in the nal application (Figure 1).
This target sets the required functionality and perfor-
mance of the active ingredient. This could be the pres-
ence of a dened quantity of vitamins or minerals (heat
sensitive nutrients) in a food product or the mainte-
nance of a bioactive form during the shelf life and the
digestion of a food product. Subsequently, the physi-
cal, chemical and biological properties of these nutri-
ents and the conditions prevailing in the food matrix
are analyzed (Figure 1). Such properties of these nutri-
ents include the physical properties, including phase
behaviour and molecular mobility, chemical reactivity
and conditions under which the physiological and sen-
sory characteristics are maintained and they eectively
determine the application window of the sensitive nu-
trients. If the target can be satised is then determined
by the conditions prevailing in the food matrix, during
manufacturing, storage and consumption. For deliv-
ery of heat sensitive nutrients through food product,
we have only a very limited exibility in adapting the
conditions in the food matrix to match the window
of application of these ingredients. Consequently, of-
ten conditions in the food matrix have to be accepted
which are detrimental to the stability and functionality
of the sensitive ingredient. In such situations, the sen-
sitive ingredient and the product may be said to be in-
compatible and a successful product development sat-
isfying the original requirements on the functionality
and performance of the active ingredient turns out to
be impossible. However, having clearly identied both
the conditions required for maintenance of the per-
formance of the sensitive ingredient and the limits to
the conditions set by the food matrix, one may dene
the functionality needed to resolve the causes of the
incompatibility of sensitive ingredient and food matrix.
The functionality is dened solely based on the analysis
of the interaction of sensitive ingredients, its stability
and food matrix and it does not yet relate to a specic
technology. In fact, a functionality dened in this way
may not even have an existing associated technology.
The major advantage of introducing the concept func-
tionality is that it postpones the selection of a technol-
ogy to a later stage in order to allow the optimal match-
ing of the dierent factors indicated in Figure-1. It
thereby enables a clear denition of the requirements
a novel technology should full in satisfying the spe-
cic application. Based on the dened functionalities,
one is in a position to select or develop an appropriate
2.1 Case Study: Delivery of Probiotic Cultures
through Food Systems
Job Ubbink [16] has studied application of Retro-
design approach for stability of probiotic cultures in
Food Matrix (Figure 2).
Figure 2. Retro-analysis of the delivery of probiotics in
food matrices
Probiotics are used as living microbial food additives
that benecially aect the host organism by improving
its intestinal microbial balance [18]. Most of the probi-
otic bacteria, in particular bidobacteria, are sensitive
microorganisms with low survival to stresses occurring
during the production, storage and consumption of
food products. Large fraction of the microorganisms
will lose their viability already before the moment of
consumption of the food product. These losses are
commonly larger than 1 log during the shelf life of the
product, but may be much higher. A number of tech-
nologies and strategies are being developed to sup-
port the survival of probiotics in food products during
Journal of Hygienic Engineering and Design
processing and storage, but the range of application of
such technologies and strategies is usually restricted to
a limited variation in conditions. One of the solutions
for probiotic stability is to use probiotic isolates and
extracts instead of Functionalities, viable microorgan-
isms. However, studies have shown that probiotic ex-
tracts and isolates cannot completely replace live pro-
biotics. Therefore, eective technologies are required
to stabilize microorganisms in the food matrix to be
able to develop probiotic food products. Strategies for
the stabilization of probiotic cultures in such dehydrat-
ed states develops based on general observations on
the response of the cultures to varying environmen-
tal conditions. Hence, application of Probiotic micro-
organisms is done in dehydrated food products, with
a water activity typically between 0.3 and 0.5 having
a shelf life of 1 - 2 years at room temperature. Under
these conditions, probiotic microorganisms lose their
viability in few months. In order to increase probiotic
stability in dehydrated products, the cultures store in
a very dry state (dehydrated regime). The probiotic vi-
ability rapidly increases with decreasing water activity.
This can be achieved by drying the product matrix to
the required water content. This is costly solution as
product weight loses from 1% up to 10% during de-
hydration. In addition, rendering a product extremely
dry may alter numerous product characteristics like
texture, palatability, and solubility. Another strategy to
protect probiotic microorganisms against the eects
of moisture is by encapsulation of the dry biomass in
materials, which form a barrier towards water. However
this has got limitations because hydrophobic food
materials like lipids have appreciable rates of mois-
ture migration. Protection against moisture strongly
enhances probiotic viability during storage; may be
due to moisture dependence reactions, including oxi-
dation, or to the eects of water on the conformations
of biological macromolecules. The impact of oxidation
reactions on probiotic stability may be limited by en-
capsulation of the microorganisms in a material with
high oxygen barrier properties, such amorphous glassy
carbohydrates which are having multiple associated
functionalities. [19]. Glassy carbohydrates are thought
to play an important role in the stabilization of fragile
biological structures such as lipid membranes, proteins
and nucleic acids by forming a physical stable matrix
interacting with the biological structure via hydrogen
bonding [20]. Microbiology is used as Stabilization
strategies complementary to previously discussed
physicochemical strategies. Strain selection and stress
adaptation, are become an important strategy to ad-
just probiotic viability [21]. Stress adaptation consists
in the application of sub-lethal or gradually increas-
ing doses of stress in order to stimulate an adaptive
cellular response that enables the microorganism to
resist a similar, but more intense stress at a later stage
[22]. Genetic tools, including bioinformatics of entire
genome sequences, were being used to increase the
understanding of molecular mechanisms of microbial
adaptation and protection [23].
Thus, structured analysis based on the ‘retro-design’
concept is useful as it oers a rational way to disentan-
gle the various physico-chemical and biological factors
determining probiotic stability. The nal processing
strategy will therefore not be optimal regarding a sin-
gle process step or ingredient but rather the best com-
promise in terms of the target product and the request-
ed product specications.
In this review, we have focused upon the types of deliv-
ery systems used for sensitive products, Novel thermal
and Non-thermal processing techniques with their im-
pact on sensitive nutrients. Finally heat sensitive nutri-
ents with their food application have been described.
Bio-fortication of nutrients is relatively recent concept
that needs to be studied extensively before implemen-
tation on Food Sector.
2.2 Types of Nutrient Delivery Systems
A wide selection of delivery systems is available for the
use in food systems. Ultimately, one would like to relate
the characteristics of the delivery systems to the func-
tional attributes of the nal product, such as sensory,
physico-chemical and biological nutritional impact
2.2.1 Powder particles
Spray-drying (micro) encapsulation has been used in
the food industry to provide, protection against deg-
radation/oxidation, and to convert liquids to powders.
Microencapsulation is dened as a process in which
tiny particles or droplets of the active ingredient(s) are
surrounded by a coating, or embedded in a homoge-
neous or heterogeneous matrix, to give small capsules
with many useful properties. Microencapsulation can
also provide a physical barrier between dierent active
ingredients in the solid product. microencapsulation is
done by spray drying, freeze drying, uid bed coating
and extrusion. Solid microcapsules represent the large
majorities of delivery systems used in food. Particle size
ranges from 1 to 2 μm. Such colloidal systems are much
less susceptible to creaming or sedimentation in the -
nal fortied liquid product. In order to avoid creaming
sedimentation in the latter systems, the aqueous con-
tinuous phase has to be viscous or gellied or density
matching components have to be added.
2.2.2 Oil in water emulsion
Oil in water emulsion such as milk, yogurt drinks, dress-
ings, sauces or mayonnaise, are ubiquitous in food.
Their oil droplets can easily be used for the delivery of
Journal of Hygienic Engineering and Design
lipophilic active ingredients. For example Vitamin E or
its derivatives are frequently added to the oil phase of
o/w emulsion products for fortication reasons or in
order to stabilize unsaturated oils against oxidation [24
and 25].
Since vitamin E acetate is chemically more stable than
vitamin E itself, it is especially used in food technology
for fortication reasons. For many nutrients, however,
a classical emulsion delivery system does not oer the
desired properties in terms of solubilization (e.g. pre-
venting crystallisation), protection against chemical
degradation or inducing the desired nutritional activ-
ity. For example, classical emulsion systems do not pro-
tect unsaturated triglycerides, essential oils, vitamins A
and D eciently against degradation.
Therefore other ideas are needed to deliver such in-
gredients without losing their nutritional eect during
shelf-life of the product. One way to achieve this is by
controlling the composition and structure of the oil
droplet interface, i.e., by building around the oil drop-
lets multilayer of surfactants.
- Multilayer emulsion system
McClements and co-workers [26] showed that when
stabilizing oil droplets rst with an anionic surfactant,
such as a phospholipid, and then adding a positively
charged polymer, such as chitosan to the emulsion, the
droplets are coated with a surfactant-polymermem-
brane, which gives the globules a positive charge. It
was observed that this kind of emulsion protects more
eciently Ω 3 fatty acids and essential oils (citral and
limonene) from oxidation that ordinary emulsions sta-
bilized by a single surfactant or amphiphilic layer. The
observed eect against oxidation of the oil droplets
in this multilayer emulsion system was attributed to
the net positively charged interface. A positive charge
around oil droplets hinders the contact with transition
metals, like iron or zinc, and as a consequence, pre-
vents them to act as a pro-oxidant of the oil droplets. It
is also suitable for water–oil droplet interface, reducing
oxidation of sensitive oil droplets, like poly-unsaturat-
ed fatty acids (PUFA), essential oils such as citral and
limonene [27].
-Double Emulsion
Double emulsions, also often denoted as ‘multiple
emulsions’, are “emulsions of an emulsion, e.g. a water-
in-oil emulsion dispersed in an aqueous phase (water-
in-oil-in-water, W/O/W). Such emulsions are interesting
as delivery systems, since, in principle, the water drop-
lets inside the oil droplets can be used to deliver (un-
stable) hydrophilic active ingredients separating them
from the outer aqueous phase of the food product.
Therefore, most studied applications of double emul-
sions are related to the control of the release of hydro-
philic substances from the inner to the outer aqueous
phase [28]. Benichou [29] studied the double emulsion
stabilization potential of WPI (Whey Protein Isolate)/
polysaccharide(e.g. xanthan gum) complexes in com-
parison to each of the biopolymers alone. A synergis-
tic positive eect with regard to the double emulsion
stability was demonstrated, which was associated to
modied surface properties induced by the adsorption
of the complexes. The authors also showed that these
double emulsions can be used for entrapping hydro-
philic vitamins, such as vitamin B1, into the inner aque-
ous phase. By means of Dierential Pulse Polarography
it was possible to follow the real-time release of the en-
trapped vitamins from the core of the W/O/W double
emulsion droplets to the outer aqueous phase.
- Nanoemulsions
Nanoemulsions, often also called miniemulsions, are
emulsions consisting of droplets which are signicantly
(by a factor of 10 or so) smaller than the droplets pres-
ent in ordinary emulsions. The very small droplet size
of nanoemulsions (20 - 200 nm) makes them resistant
to physical destabilization via gravitational separation,
occulation and/or coalescence. Nanoemulsions are
resistance due to creaming because of Brownian move-
ments but they are particularly prone to growth in par-
ticle size over a time by a process known as Ostwald
ripening [30]. Yuang [31] investigated oil-in-water na-
noemulsions of β-carotene produced by high pressure
homogenization. While the physical stability of the
nanoemulsions, which were stabilized by polysorbate
emulsiers, was quite acceptable, signicant chemical
degradation of the delivered β-carotene occurred dur-
ing storage.
-Solid lipid nanoparticles carriers
Solid lipid nanoparticles carriers (SLNs) have some sim-
ilarities with nanoemulsion systems. The diameter of
such lipid particles can be also quite small, i.e. in the
range between 50 nm and 1 μm. SLNs consist of a solid
or semi-solid lipidic core containing lipophilic active in-
gredients. Active ingredients can be solubilised homo-
geneously either in the core of the SLNs or in the outside
part. This physical property allows a better control of
both the physical (against recrystallisation) and chem-
ical (against degradation) stability of the delivered nu-
trients. The preparation of SLNs is achieved by heating
the lipidic core components above their melting point,
and then using common emulsion or microemulsion
technology, i.e., homogenisation or mixing of the melt-
ed lipidic phase with a cold aqueous solution generat-
ing re-crystallised lipidic particles. The main diculty
associated with SLNs production is to control the lipid
Journal of Hygienic Engineering and Design
polymorphism. Triglycerides, for example, can be pres-
ent in three dierent crystalline structures α (spherical),
β (needle shaped), and β (needle shaped) [32]. Carlotti
[33] found that between 50 and 70% of retinol remains
undegraded when ‘encapsulated’ in SLNs made of Cetyl
palmitate (30% of vitamin A was degraded), Glyceryl
behenate (49% degradation) and palmitic acid (34%
degradation), while 8% retinol remains when delivered
in standard oil-in-water emulsions.
But during heat treatment active element may be ex-
posed to high temperature during the preparation of
the lipid carrier material leading to chemical degrada-
tion. Finally, saturated lipids are needed to obtain these
kinds of delivery system. Such lipids are not the pre-
ferred ones in terms of nutrition and health.
2.2.3 Molecular Complex
Another strategy to deliver active ingredients in aque-
ous foods is by physically complexing them with other
molecules, hoping that in this way a better solubilisa-
tion and/or an increase in the chemical stability of the
complex bioactive can be achieved. In this context a
molecular complex is referring to the physical associ-
ation between a host and a guest (active ingredient)
- Cyclodextrins
Cyclodextrins are cyclic (or taurus shape) oligosaccha-
rides having a hydrophilic outer surface insuring good
dissolution of the complex in an aqueous environment.
Cyclodextrins (α-6, β-7, γ-8) contain a lipophilic cavity
(0.5-0.8 nm) enabling to host relatively small lipophilic
or amphiphilic constituents, such as fatty acids, vegeta-
ble and essential oils, nucleic acids, vitamins and hor-
mones [34 and 35].
- Molecular association with biopolymer
Active molecules form physical complexes with a va-
riety of other naturally occurring food components.
Such systems are the base for designing ‘natural’ de-
livery systems. Amylose present in starch, which adopt
a helical structure generating a cavity of about 0.5 nm
in diameter. Small molecules like aromas solubilize in
this cavity and can bbe used in Food Delivery systems.
Proteins and peptides are amphiphilic molecules.
They are also relatively soluble in water and can bind
lipophilic or amphiphilic active ingredients. Semo [36]
used casein micelles to solubilize vitamin D2. Sodium
caseinate, CaCl2 and K2HPO4 were used to encapsulate
the vitamin and reconstitute the casein micelle solu-
tion and study their protective properties. It was found
that the casein micelle can provide a partial protection
against UV-light induced degradation compared to the
serum media of the casein micelle dispersion, which
was used as a control.
2.2.4 Self-assembly delivery structures
Tanford [37] dene the dimensionless surfactant pack-
ing parameter for a semi quantitative description of
the relation between surfactant molecular shape and
self-assembly phase formation. Packing parameter
is ration of the molecular volume of the hydrophobic
moiety, the molecular length of the hydrocarbon chain
and is the eective (or hydrated) cross-sectional area
of the polar head-group. Depending on packing fac-
tor, dierent self-assembly structures are formed. If
Packing parameter is less than 1, structures like normal
micelles, hexagonal (Hi) or cubic phases are formed. If
Packing parameter is close to 1, a lamellar liquid crys-
talline (Lα) phase is formed, which when dispersed into
water gives rise to vesicles or liposomes formation. If
packing parameter is more than 1, reversed self-assem-
bly structures, such as reversed micelles, reversed hex-
agonal or reversed cubic structures are formed.
Self-assembly structures, such as micelles, microemul-
sions, and liquid crystalline phases, are formed by the
spontaneous association of surfactants in aqueous (or
oil) phases. These consist of polar lipids such as mono-
glyceraldehydes and phospholipids. These are ther-
modynamically stable and are formed spontaneously
and as compared to nanoemulsion , microemulsion
requires large amount of surfactant [38]. For exam-
ple-polysorbate used to prepared β-carotene, lyco-
pene, lutein or phytosterols.
- Liposomes
Liposomes, often also denoted as vesicles, are formed
when the surfactant molecules have a Packing param-
eter close to 1. Contrary to microemulsions their forma-
tion is often not completely spontaneous. When mixed
with water the surfactant spontaneously forms a lamel-
lar phase, which then needs to be dispersed to form
vesicles. Liposomes can contain (i) one bilayer forming
unilamellar vesicles (ULV), (ii) several concentric bilay-
ers forming multi lamellar vesicles or (iii) non concen-
tric bilayers forming multi vesicular vesicles (MVV). The
size of these structures can be rather small (in the range
of 20 nm) or rather large (exceeding 1 μm) [39].
2.2.5 Dispersed reversed surfactant systems
Reversed phases are made out of surfactants that have
a Packing parameter more than 1. They are formed by
lipophilic surfactants such as unsaturated monoglycer-
ides or phospholipids. Reverse microemulsion droplets
can solubilize non-esteried phytosterol molecules in
Journal of Hygienic Engineering and Design
much larger amounts than in ordinary oil droplets can
do. Another interesting application of reversed micro-
emulsion droplets deals with the controlled release of
aromas [39]. Table 2 summarizes the various types of
systems which can be used for the delivery of sensitive
ingredients in aqueous liquid products.
Table 2. Delivery systems for sensitive nutrients
Delivery systems Particle
Size Salient Feature Limitations
1. Powder particles
- Glass encapsulation
- Core-shell capsule
- Matrix capsule
10 µm –
1 mm
Good encapsulation
for solid products
Limited application
for delivery of
sensitive nutrient in
liquid foods
2. Oil in Water Emulsion
- Ordinary emulsion
- Multilayered emulsion
- Double emulsion
- Nano-emulsions
- Solid lipidnanoparticles
carriers (SLNS)
100 nm
– 10 µm
50 nm –
1 µm
- Hosts lipophilic
- Better chemical
protection of
sensitive oil
achieved when
emulsion or SLNS
-controlled released
with SLNS
- Physical stability
- Polymorphism
stability and
encapsulation for
SLNS dicult to
3. Molecular Complex
- Cyclod3rins
- Molecular associated
with biopolymers
(Amylose, Proteins,
Protein aggregates)
- Solubilisation of
small lipophilic
- Protection of
sensitive molecules
Limited Loading
Capacity of
Sensitive Nutrient
with Molecular
4. Self-assembly delivery systems
Oil in Water Micro-
5nm -
100 nm
-Solubilisation of
lipophilic molecules
of crystallizing
-Increased in
-Large amount of
surfactant needed
-often o taste
-Used surfactant
often not well
Liposomes, Vesicles 20 nm -
100 µm
- Solubilisation of
hydrophilic and
lipophilic molecules
- Sustained released
of nutrients
- Higher cost
(ingredients and
- Poor loading
eciency and
5. Self - assembly Structures
- Cubosomes
- Hoxosomes
- Dispersed reversed
- Microencapsulations
- Micellosomes
100 nm
– 1 µm
amphiphilic and
lipophilic mol.
-Controlled released
of crystallizing
Large amounts of
surfactant may be
2.3 Use of Novel Thermal and Non-Thermal Techno-
logies for Heat Sensitive Materials
Traditional thermal treatments are a cornerstone of
the food industry providing required safety proles
and extensions of shelf-life. However, such treatments
may lead to losses of desired organoleptic properties
and damage to temperature labile nutrients and vita-
mins. Consequently, the food industry has long sought
alternative or synergistic approaches to provide the
treatment objectives. Novel thermal and non-thermal
technologies have been designed to meet the required
food product safety or shelf-life demands while mini-
mizing the eects on its nutritional and quality attrib-
utes. The potential of novel thermal electromagnetic
technologies such as Ohmic and microwave heating,
are promising alternatives to conventional methods of
heat processing. Such technologies are regarded as a
volumetric form of heating, in which thermal energy
is generated directly inside the food, does not rely on
limiting heat transfer coecients and the requirement
of high wall temperatures. Non-thermal processing is
often used to designate technologies that are eective
at ambient or sub-lethal temperatures. Some of these
technologies are enlisted below with their mechanism
of microbial inactivation and Food Applications. Very
limited number of studies has been done on eect of
these technologies on Heat Sensitive Nutrients in Food.
2.3.1 Microwave and Radio-Frequency processing
Microwave and radio frequency heating refers to the
use of electromagnetic waves of certain frequencies
to generate heat in a material [40 and 41]. Microwave
food processing uses dierent frequencies, allocated
by Federal Communications Commission (FCC), such
as for United States, 2450 (Domestic Use) and 915 MHz
(Industrial Purpose), similarly 5800 and 24125 MHz is
used for Heating Purpose. Radio frequency is used at
three dierent frequencies, 13.56 MHz, 27.12 MHz and
40.68 MHz. This is used in Food pasteurization, baking
and other processes in the food industry [42 and 43].
Heating principle of Microwave is similarly as that of
Radio Frequency involves two mechanisms - Dielectric
and Ionic. Water present in the food is the primary com-
ponent responsible for dielectric heating. Due to dipo-
lar nature, water molecules try to follow the electric
eld associated with electromagnetic radiation as it os-
cillates at the very high frequencies. Food Material to be
heated is placed between two metal plates which form
an electrical capacitor. The material becomes “lossy” di-
electric and absorbs energy from radio frequency gen-
erator which is connected across the two plates known
as electrodes. Such oscillations of the water molecules
produce heat. The second mechanism of heating with
microwaves and radio frequency is through the oscilla-
tory migration of ions in the food that generates heat
Journal of Hygienic Engineering and Design
under the inuence of the oscillating electric eld [44
and 45]. Salient features are Rapid and Uniform heat-
ing, Selective heating, Instant control, energy ecient.
Two mechanisms for inactivation of microorganisms by
microwaves have been suggested. The rst states that
microbial inactivation by heat through mechanisms
comparable to other biophysical processes induced by
heat, such as denaturation of enzymes, proteins, nucle-
ic acids, or other vital components, as well as disruption
of membranes [46]. A second mechanism for inactiva-
tion by microwaves involves non-thermal eects due
to selective heating, electroporation, cell membrane
rupture, and magnetic eld coupling [47].
2.3.2 Ohmic & Inductive heating
Ohmic heating (also referred as Joule heating, electrical
resistance heating, direct electrical resistance heating,
electroheating, and electroconductive heating) is de-
ned as a process wherein electric currents are passed
through foods with the primary purpose of heating
them. The heating occurs in the form of internal en-
ergy generation within the material. Salient feature of
Ohmic heating is presence of electrodes contacting
the food (unlike to microwave heating), frequency, and
waveform [48]. Ohmic heating is a thermal process in
which heat is internally generated by the passage of al-
ternating electrical current through a body such as food
system that serves as an electrical resistance. During
Ohmic heating, AC voltage is applied to the electrodes
at both ends of product body. The rate of heating is
directly proportional to electric eld strength, electri-
cal conductivity & the type of food being heated. The
electrical eld strength can be controlled by adjusting
the electrode gap or applied voltage, while the electri-
cal conductivities of foods vary greatly, but can be ad-
justed by the addition of electrolytes. Ohmic Heating
is having salient features: Rapid heating independent
of Heat transfer coecients, without hot surfaces for
heat transfer, heat sensitive food components are not
damaged by localized over-heating, suitable for vis-
cous liquids, energy ecient, suitable for continuous
processing [49].
The principal mechanisms of microbial inactivation are
thermal and mild electroporation occurs during Ohmic
heating. Electroporation is due to its low frequency (50
- 60 Hz), which allows cell walls to build up charges and
form pores. This is in contrast to high-frequency meth-
ods such as radio or microwave frequency heating,
where the electric eld is essentially reversed before
sucient charge buildup occurs at the cell walls. Ohmic
Heating is used for blanching, evaporation, dehydra-
tion, fermentation, extraction, sterilization, pasteuriza-
tion and heating of foods to serving temperature [49].
2.3.3 High Pressure processing
High-pressure processing (HPP) is a method of food
processing where food is subjected to elevated pres-
sures (up to 87,000 pounds per square inch or approx-
imately 600 MPa), with or without the addition of heat,
to achieve microbial inactivation or to alter the food
attributes in order to achieve consumer-desired quali-
ties. The technology is also referred as High Hydrostatic
Pressure Processing (HHP) and Ultra High Pressure
Processing (UHP). During pressure treatment, the ap-
plication of pressure is governed by Le Chatelier’s prin-
ciple. Due to iso-static pressure treatment, pressure
is transmitted in a uniform and quasi-instantaneous
manner throughout the whole sample, thus making
the process independent of volume and geometry of
the product. It has been generally accepted that the
iso-static principle is assumed to be true for high-pres-
sure food processing applications except heteroge-
nous large solid samples. Once the desired pressure
is reached, it is maintained for an extended period of
time without any further energy input. Due to micro-
scopic ordering at constant temperature, an increase in
pressure increases the degree of ordering of molecules
of a given substance. Fruits containing Air-spaces such
as Marshmallows or strawberries containing large air
packets are deformed during pressure treatment due
to dierences between the compressibility of air and
the rest of the food constutuents.
Fluid foods are processed in batch or semi-continuous
mode, consists of Pressure vessel, Top and bottom end
closures, Yoke (structure for restraining end closures),
High pressure pump and intensier for generating tar-
get pressures, Process control and instrumentation, A
handling system for loading and removing the prod-
uct. In the batch mode, liquid product is pre-packaged,
preconditioned and pressure treated. Semi-continuous
pressure equipment employs two or more pressure
vessels with free-oating pistons arranged to compress
the liquid foods [50].
In Pressure-assisted thermal processing (PATP), the
food is subjected to a combination of elevated pres-
sures and moderate heat for short duration. One of
the unique advantages of PATP is its ability to pro-
vide a rapid and uniform increase in the temperature
of treated food samples. High pressures at ambient
or chilled temperatures have been employed for pro-
cessing a number of liquid and semi-solid foods such
as fruit juices, purees, smoothies, jellies, guacamole,
etc. Several studies evaluated the benecial eects of
pressure treatment over conventional treatment on
preserving quality attributes of foods. Small molecules
such as vitamins, and avor compounds remain unaf-
fected by high pressure, while the structure of the large
molecules such as proteins, enzymes, polysaccharides,
and nucleic acid may be altered [50].
Journal of Hygienic Engineering and Design
2.3.4 Irradiation of food
Irradiation is a food-processing treatment endorsed
by a variety of professional and governmental organ-
izations. In reviewing the scientic literature on the
process, the US Food and Drug Administration (CFR,
2000) the US General Accounting Oce (GAO, 2000)
the American Dietetic Association (ADA, 2000) and
the UN World Health Organization (WHO, 1999) have
endorsed the technology as safe and eective. Recent
Studies shows that no detectable furan was produced
in most fresh and fresh-cut fruits and vegetables fol-
lowing a dose of 5 kilogray (10 kGy), a very high dose
in the context of food processing [51]. Irradiation Dose
ranges are characterized as low (less than 3 kGy), medi-
um (more than 3 and less than 10 kGy), or high (more
than 10 kGy). The irradiation treatment is based on the
energy absorbed by Food Material. There are currently
three methods of delivering doses of ionizing radiation
for food processing. Gamma radiations are produced
by radioactive isotope sources such as cobalt-60 (Co-
60) and Cacsium-137(Cs-137). These are highly pene-
trative rays. Gamma ray sources produce radioactivity
constantly and so need heavy containment and shield-
ing for safety. Dosing is controlled by exposure time.
Electron beams (e-beams) are streams of high energy
electrons (beta particles) produced by an electron gun
(can be turned on and o. Electron beams have limit-
ed penetration (3-4 cm) into food, and do not require
such high levels of containment and shielding to pro-
tect workers. X-rays are used to process foods is more
recent and coming as separate processing technology
Irradiation is a non-thermal process that can be applied
to juices, beverages, and other uid foods. Successful
use of this technology is contingent on developing irra-
diation protocols that achieve the desired antimicrobial
and food-safety goals while preserving (or improving)
the sensory and nutritional value of the product [53].
Reyes and Cisneros-Zevallos [54] showed Irradiation
eects on anthocyanin pigments depend upon the
nature of anthocyanin for example; diglycosides are
relatively stable towards irradiation dose compared to
monoglycosides. Eect of irradiation (1 - 3.1 kGy) on
mango shows minor eect of irradiation dose on the
total phenolic content while there was a signicant in-
crease in avonols after an 18 day storage period for
the irradiated fruits (at 3.1 kGy). Study conducted by
Lopez-Rubira [55] demonstrated insignicant changes
in anthocyanins and antioxidant activity of pomegran-
ate arils after exposure to UV-C (0.56 - 13.62 kJ/m2).
2.3.5 Pulsed X-ray processing
Electrons have a limited penetration depth of about 5
cm in food, while X-rays have signicantly higher pen-
etration depths (60 - 400 cm) depending upon the en-
ergy used. Pulsed X-rays are generated using radionu-
clide sources that utilizes a solid state-opening switch
to generate electron beam X-ray pulses of high inten-
The radionuclides Co-60 and Cs-137 are produced by
neutron bombardment of Co-59 and Cs-136 as a ssion
fragment of a nuclear power reactor operation. They
emit γ-radiation of discrete energy. These radionuclide
sources require permanent massive concrete shielding
to protect workers and the environment from their per-
manent radiation.
Second approach is electrically driven radiation sourc-
es that switch o when the radiation is no longer need-
ed are easier to incorporate into existing food pro-
cessing plant. Linear Induction Electron Acceleration
(LIEA) generates broad spectrum ionizing radiation by
targeting the accelerated electron beam to collide with
a heavy metal converter plate. This plate converts the
electron beam in X-rays with a broad-band photon-en-
ergy spectrum. Then, by ltering the energy spectrum
of the radiation, high-energy, highly penetrating radia-
tion is produced, resulting in smaller variations in dose
uniformity of food packages and higher quality. LIEA
can deliver dose rates many orders of magnitude high-
er than possible with Co-60 sources. Consequently,
ultra-short, high-intensity radiation treatments can be
applied, resulting in higher local radical concentrations
and favoring radical-radical recombination reactions.
This reduces the diusion of radical species, which are
thought to be responsible for undesirable eects of ir-
radiation on food quality. Salient Features of this tech-
nology are (1) exibility of controlling the direction of
the electrically produced radiation; (2) the exibility of
shaping the geometry of the radiation eld to accom-
modate dierent package sizes; and (3) its high repro-
ducibility and versatility. The kinetic energy limit for
X-ray irradiation is 5MeV [56].
X-ray treatment reduces or eliminates Salmonella se-
rovars in poultry, mold growth on strawberries and
sprout development in potatoes. Salmonella serovars
have been found to be the most radiation sensitive
of all pathogenic organisms on foods. As a method of
food preservation, X-ray treatment has low energy re-
Microbial inactivation by all types of ionizing radiation
is thought to happen through 2 main mechanisms: di-
rect interaction of the radiation with cell components
and indirect action from radiolytic products, such as
the water radicals. The primary target of ionizing radia-
tion appears to be chromosomal DNA, although eects
on the cytoplasmic membrane may also play a role.
Changes to chromosomal DNA and/or cytoplasmic
membrane can cause microbial inactivation or growth
inhibition. Many studies have shown that ions, excit-
ed atoms and molecules generated during irradiation
have no toxic eect on humans [57].
Journal of Hygienic Engineering and Design
2.3.6 Ultra-Violet pasteurization
Ultraviolet processing involves the use of radiation from
the ultraviolet region of the electromagnetic spectrum
for purposes of disinfection. Typically, the wavelength
for UV processing ranges from 100 to 400 nm. This
range is further subdivided into UVA (315 to 400 nm) ;
UVB (280 to 315 nm) ; UVC (200 to 280 nm) UVC is called
the germicidal range since it eectively inactivates bac-
teria and viruses, and the vacuum UV range. (100 to 200
nm) that can be absorbed by almost all substances and
thus can be transmitted only in a vacuum. The germi-
cidal properties of ultraviolet irradiation are due to the
DNA absorption of the UV light, causing crosslinking be-
tween neighboring pyrimidine nucleoside bases (thy-
mine and cytosine) in the same DNA strand [58]. Due
to the mutated base, formation of the hydrogen bonds
to the purine bases on the opposite strand is impaired.
DNA transcription and replication is thereby blocked,
compromising cellular functions and eventually leading
to cell death. The amount of crosslinking is proportional
to the amount of UV exposure. The level of mutations
that can be reversed depends on the UV repair system
present in the target microorganism. Once the thresh-
old of crosslinking has been exceeded, the number of
crosslinks is beyond repair, and cell death occurs [59].
This mechanism of inactivation results in a sigmoidal
curve of microbial population reduction. To achieve mi-
crobial inactivation, the UV radiant exposure must be at
least 400 J/m2 in all parts of the product. Critical factors
include the transmissivity of the product, the geometric
conguration of the reactor, the power, wavelength and
physical arrangement of the UV source(s), the product
ow prole, and the radiation path length. UV may be
used in combination with other alternative process-
ing technologies, including various powerful oxidizing
agents such as ozone and hydrogen peroxide, among
others. Applications include disinfection of water sup-
plies and food contact surfaces. Recently, interest has
increased in using UV to reduce microbial counts in juic-
es [60].
UV light has broad antimicrobial action, providing eec-
tive inactivation of viruses, vegetative bacteria, bacterial
spores, yeasts, conidia and parasites. UV-light treatment
of liquid foods is performed by use of continuous UV
sources. Continuous UV treatments are performed by
mercury vapour-lamps that continuously emit UV pho-
tons and are called continuous-wave UV (CW UV) lamps
in both monochromatic and polychromatic modes [61].
UV-C illumination of grapes induces stilbene synthesis,
especially that of trans-resveratrol, which will yield a
phytochemical-enriched grape juice [60].
2.3.7 Pulsed Light processing
Pulsed light is a technique to decontaminate surfaces
by killing microorganisms using short time pulses of
an intense broad spectrum, rich in UV-C light (portion
of the electromagnetic spectrum corresponding to the
band between 200 and 280 nm). Material to be steri-
lized is exposed to xenon ash lamp that multiply the
power many fold. Power is magnied by storing elec-
tricity in a capacitor over relatively long times (fractions
of a second) and releasing it in a short time (millionths
or thousandths of a second). The emitted light ash has
a high peak power and consists of wavelengths from
200 to 1100 nm. The technique used to produce ashes
originates, besides high peak power, a greater relative
production of light with shorter bactericidal wave-
lengths [62].
The germicidal eect of UV light on bacteria is primarily
due to the formation of pyrimidine dimers, mainly thy-
mine dimers. The dimer inhibits the formation of new
DNA chains in the process of cell replication, thus re-
sulting in the inactivation (inability to replicate, called
clonogenic death) of aected microorganisms by UV
rays. On bacterial spores, UV-C treatment results mainly
in the formation of the ‘‘spore photoproduct’’ 5-thymi-
nyl-5,6-dihydrothymine, and in single-strand breaks,
double-strand breaks and cyclobutane pyrimidine di-
mers. As per photothermal eect, UV light with uence
(measured in Joule/meter2 and is the energy received
from the lamp by the sample per unit area during the
treatment) exceeding 0.5 J/cm2, the disinfection is
achieved through a rupture of bacteria during their
momentous overheating caused by absorption of all
UV light from a ash lamp [62]. Advantages of
Pulsed Lights Processing are rapid disinfection, lack of
residual compounds, absence of any extraneous chem-
ical, environment friendly. Areas need improvements
are Sample Heating by lamp, shadowing eect of mi-
croorganism, limited application in caser of irregular
and opaque surfaces [62]. UV-C illumination decreas-
es ascorbic acid content of juices at a similar level to
that caused by thermal treatments [63]. Also for orange
juice, a treatment of 299 mJ/cm2 destroyed about
50% riboavin and β-carotene, 17% vitamin C, 11% vi-
tamin A, and did not aect folic acid or vitamin E. In
apple juice, the reduction is reported to be from 5.4 to
4.0 mg/100 ml of juice. Besides the eect on micronu-
trients, the potential eect of UV light on antioxidant
capacity and related compounds is also important to
assess due to the benecial eects of phytochemicals
2.3.8 Oscillating Magnetic Fields for food preserva-
Static Magnetic Field (SMF) and oscillating Magnetic
Fields (OMF) are used for their potential as microbial
inactivation techniques. For SMF, the magnetic eld in-
tensity is constant with time, while an OMF is applied in
the form of constant amplitude or decaying amplitude
sinusoidal waves. The magnetic elds may be homoge-
Journal of Hygienic Engineering and Design
neous (uniform magnetic eld intensity) or heteroge-
neous (magnetic eld intensity is inversely proportion-
al to distance from coil) [65]. OMF is used in the form of
pulses reverses the charge for each pulse, and the in-
tensity of each pulse decreases with time to about 10%
of the initial intensity [66]. Preservation of foods with
OMF involves sealing food in a plastic bag and subject-
ing it to 1 to 100 pulses in an OMF with a frequency
between 5 to 500 kHz at temperatures in the range of 0
to 50oC for a total exposure time ranging from 25 to 100
milli-seconds. Frequencies higher than 500 kHz are less
eective for microbial inactivation and tend to heat
the food material [67]. Magnetic eld treatments are
carried out at atmospheric pressure and at moderate
temperatures. The temperature of the food increases
2-5 0C [65].
Studies have proposed two theories to explain the in-
activation mechanisms for micro-organism and patho-
genic cells placed in SMF or OMF. The rst theory states
that OMF loose the bonds between ions and proteins.
Many proteins vital to the cell metabolism contain
ions such as enzymes, hormones, pre-cursors which
get damaged by OMF. A second theory considers the
eect of SMF and OMF on calcium ions bound in cal-
cium-binding proteins, such as calmodulin. Changing
magnetic eld to calmodulin causes cyclotron reso-
nance resulting in loosening of the bond between the
calcium ion and the calmodulin. This ultimately causes
metabolic disorder followed by cell death [66].
2.3.9 Use of Pulse Electric Field
PEF utilizes high intensity electric eld pulses to inacti-
vate microorganisms mainly in liquid foods at relatively
low or moderate temperatures (less than 600C), whilst
preserving the fresh avour, colour and integrity of
heat sensitive components. A typical PEF food process-
ing unit comprises of a high voltage pulse generator, a
treatment chamber, a uid handling system and con-
trol and monitoring devices. Depending on the par-
ticular PEF systems used, typical PEF treatment param-
eters include pulsed eld intensity of 15 - 50,
pulse width of 1 - 5 microseconds, and pulse frequency
of 200 - 400 Hz (pulses/s). Key parameters inuencing
microbial inactivation in PEF are pulse width, pulse
shape, adequate design of the treatment chamber and
polarity. Square-wave pulses are considered to be su-
perior to exponentially decaying pulses as the former
gives the treatment in a sustained and constant inten-
sity for the total duration of the pulse. Bipolar pulses
are reported to be generally more eective for microbi-
al inactivation than monopolar pulses.
The total phenolic content of a blend of orange, kiwi,
pineapple juice and soymilk was not aected by PEF
treatments conducted at 35 kV/cm, 4 microseconds
bipolar pulses at a frequency of 200 Hz for a total
treatment time of 800 microseconds and 1400 micro-
seconds. No eect of PEF was detected on phenolic
compounds. However, signicant reductions were ob-
served for vitamin C concentration which was reected
in a decrease in the antioxidant activity of the product.
Under the tested processing conditions the PEF treat-
ment caused a reduction in the vitamin C and antiox-
idant capacity which decline over time compared to
conventional thermal treatment [68 and 69].
The microbial inactivation principle is Electroporation
theory. PEF treatment at electric eld intensity greater
than a critical threshold of trans-membrane potential
of 1 V across the target cells causes irreversible pore
formation and destruction of the semi-permeable
barrier of the cell membrane. More recent studies also
show that hypothesis of microbial inactivation due to
membrane permeabilisation caused by PEF. It is gener-
ally reported that yeast cells are more sensitive to PEF
treatment than bacterial cells, and that Gram-negative
are more sensitive than Gram-positive bacterial cells
2.3.10 Low-Temperature Plasma for Food processing
A neutral gas is converted to plasma by the application
of energy in several forms including; thermal, electric
or magnetic elds and radio or microwave frequen-
cies, resulting in an increase in the kinetic energy of
the electrons of constituent gas atoms. This causes a
cascade of collisions in the gas resulting in the forma-
tion of plasma products of electrons, ions, radicals and
radiation of varying wavelengths including that in the
UV ranges. The eectiveness of plasma to inactivate
microorganisms on inert surfaces will depend greatly
on the equipment design and operating conditions
like gas type, ow rate and pressure. The methods of
generating discharges of low-temperature plasmas by
using electric elds of either DC, AC, pulsed DC, radi-
ofrequency, microwave, dielectric barrier, or electron
and laser beams. Electric elds are the most commonly
used method of generating plasmas for technological
Low-temperature plasmas are dierentiated into at-
mospheric or low pressure (in the order of 10 Pa. In the
atmospheric plasma, many collisions between the par-
ticles occur due to the density of the gas. This leads to
rapid exchanges of energy between the electrons and
heavier particles (ions, radicals and molecules) reach-
ing a steady state and resulting in temperatures of the
order of 10,000’s degrees Celsius. The chemical compo-
sition of low-temperature plasmas of nitrogen, oxygen
and carbon dioxide gas mixtures are dominated by
ions free radicals and highly reactive intermediate spe-
cies. Also if water vapour is present, highly reactive spe-
cies including H2O, H, OH are formed and also cluster
ions containing H2O. The generation of UV radiation oc-
Journal of Hygienic Engineering and Design
curs in the ranges 10 - 290 nm, and those wavelengths
above 200 nm, at a uence of several, are
responsible for microcidal eects. Plasma inactivates
both vegetative cells and bacterial endospores. Three
basic mechanisms have been attributed to the inac-
tivation of microbial spores in plasma environments.
These include destruction of DNA by UV irradiation,
volatilization of compounds from the spore surface
by UV photons and erosion or so called ‘etching’ of the
spore surface by adsorption of reactive species like free
radicals. Synergistic eects between these possible
mechanisms of inactivation can be expected, depend-
ing on the operational conditions and the design of the
plasma generator [70].
The eect is limited to the surface layers of food prod-
ucts, but since plasmas are able to ‘ow’ over the treat-
ed surface into ssures and depressions. The entire
surface can be treated, in contrast to other surface de-
contamination processes such as UV light. A number
of researchers have investigated the potential for cold
plasma treatment as a method of non-thermal decon-
tamination of ready to cook food, nuts, fresh fruits and
vegetables, cooked meats, raw chicken pieces and also
for packaging [71].
2.3.11 Chlorine Dioxide processing
Chlorine dioxide (ClO2) is one of the few compounds
that exists almost entirely as monomeric free radicals.
ClO2 cannot be compressed and stored under the pres-
sure because it is explosive, therefore the shipping of
ClO2 gas is impossible, and it has to be generated on-
site. Easy-to-use commercial systems exist on the mar-
ket for on-site ClO2 generation. They generally consist
of two sachets each one containing a precursor for ClO2
generation, which takes place upon mixing two com-
Cell membrane has been identied as the primary tar-
get of ClO2 on microbial cells. Studies show chlorine di-
oxide directly aects microbial cells by inhibiting pro-
tein synthesis, loss of permeability control. The eect
of ClO2 was related to non-specic oxidative damage
of the outer membrane leading to the destruction of
the trans-membrane ionic gradient. Some studies also
show inhibition of division and associated metabolic
damage or damage to genetic material. Use of chlorine
dioxide for microbial deactivation on Lettuce, Cabbage,
Green bell, Baby Apple pepper, Apples, Mungbean
sprout, Blueberry, Melon, cucumber have shown sat-
isfactory results. The main advantage of ClO2 gas over
aqueous sanitizers is that gas has more penetrability; it
could therefore reach microorganisms protected from
aqueous disinfectants by surface irregularities or bio-
lms [72].
2.3.12 Ozone processing
Ozone (O3) results from the rearrangement of atoms
when oxygen molecules are subjected to high-voltage
electric discharge. The product is a bluish gas with a
pungent odor and strong oxidizing properties Ozone
inactivates microorganisms through oxidization, and
residual ozone spontaneously decomposes to non-tox-
ic products (i.e. oxygen), making it an environmentally
friendly antimicrobial agent for use in the food indus-
try. The strong biocidal characteristics of ozone are due
to a combination of its high oxidizing potential and
its ability to diuse through biological membranes.
Ozone is generated at Industrial scale on demand,
in situ through various methods. Electrical (Corona)
Discharge Method includes, adequately dried air or O2
(free from particulate matter and dried to a dew point
of at least - 60 0C) is passed between two high-voltage
electrodes separated by a dielectric material, which is
usually glass. The ozone/gas mixture discharged from
the ozonator normally contains 1 - 3% ozone when us-
ing dry air, and 3 - 6% ozone when using high purity ox-
ygen as the feed gas. In Electrochemical (Cold Plasma)
Method, an electrical current is applied between an an-
ode and a cathode in an electrolytic solution contain-
ing water and a solution of highly electronegative ani-
ons. A mixture of oxygen and ozone is produced at the
anode used for microbial reduction. In Radiochemical
Ozone Generation (RCOG), high-energy irradiation of
oxygen is happened to produce ozone. In Ultraviolet
Method, ozone is formed when oxygen is exposed to
UV light of 140 - 190 nm wavelengths. This splits the
oxygen molecules into oxygen atoms, which then com-
bine with other oxygen molecules to form ozone. Some
of Extrinsic Factors such as ow rate, ozone concentra-
tion, temperature and intrinsic factors such as pH and
Organic Matter aect the ozone ecacy. Ozone is very
unstable both in the gaseous phase and in solution, de-
composing into hydroxyl, hydroperoxy and superoxide
radicals. The reactivity of ozone is attributed to the oxi-
dizing power of these free radicals. Microorganisms are
inactivated by disruption of the cell envelope or disin-
tegration leading to cell lysis. The bacterial membrane
seems to be the rst site of the attack with proteins and
unsaturated lipids in the cell membrane being the pri-
mary targets. Additionally, ozone causes alteration in
membrane permeability leading to leakage of cell con-
tents and eventually causing lysis. Ozone shows favora-
ble microbial reduction (gram negative, gram positive
bacteria and spores) in milk, gelatin, albumin, casein,
meat products, apple juice, whey, water, orange juice
Kiwi fruit is a rich source of vitamin C and contains
more ascorbic acid than citrus fruits. Barboni [74] com-
pared the eect of ozone rich storage and air storage
over a period of 7 months on the vitamin C content of
kiwi fruit. Gaseous ozone concentration was 4 mg/h in
Journal of Hygienic Engineering and Design
the chamber at a temperature of 0 0C and a humidity of
90 - 95%. The authors did not observe any signicant
change in ascorbic acid content of kiwi fruit over a 7
month storage period at an ozone concentration of 4
mg/h in the chamber (2 m3) and a storage temperature
of 0 0C. Reports on the eect of ozone on other bioac-
tive compounds of exotic fruits are limited [74].
Ozone treatments were also reported to have minor ef-
fects on anthocyanin contents in strawberries [75] and
blackberries [76].
2.3.13 Dense-Phase Carbon Dioxide processing of
uid foods
Carbon dioxide is used because of its safety, low cost,
and high purity. Dense-phase carbon dioxide (DPCD)
treatment has attracted great interest in the non-ther-
mal treatment of liquid foods or liquid model solutions.
DPCD has been shown to inactivate microorganisms as
well as conventional heat pasteurization without the
loss of nutrients or quality changes that may occur due
to thermal eects. The temperature increase induced
by the pressure build-up is negligible. The treatment
times can range from about 3 to 9 min for continuous,
or from 120 to 140 min for semi-continuous or batch
DPCD processes.
A typical batch system has a CO2 gas cylinder, a pressure
regulator, a vessel, a water bath or heater, and a CO2
release valve. The sample is placed into the vessel and
the temperature is set to the desired value. Then CO2 is
introduced into the vessel until the sample is saturated
at the desired pressure and temperature. The sample is
left in the vessel for a period of time and then the CO2
outlet valve is opened to release the gas. Some systems
contain an agitator to decrease the time to saturate of
the sample with CO2. A continuous high-pressure CO2
system has been developed to process 1 L/h of liquid
at 40.0 MPa. The sample liquid was stored in two 5 liter
high-density polyethylene containers, both connected
to the pump. CO2 passed through an in-line 0.5 μm l-
ter and a cooling system, then pumped to four mixing
points. The pressurized CO2 was mixed with the liquid
and the mixture went to a temperature-controlled
holding tube. Several valves along the holding tube
allowed for sampling at dierent residence times. The
treated liquid depressurized through a capillary tube
inside a thermostatic bath. The liquid was degassed in
two containers.
The bacteriostatic action of pressurized CO2 compro-
mises dierent steps such as solubilization of pressur-
ized CO2 in the external liquid phase, cell membrane
modication, intracellular pH decrease, key enzyme
inactivation/cellular metabolism inhibition due to in-
ternal pH lowering, direct inhibitory eect of molecular
CO2 and HCO3 on metabolism, disordering of the intra-
cellular electrolyte balance, extraction of vital constitu-
ents from cells and cell membranes, physical disruption
of cell membrane. Most of these steps occur consecu-
tively and simultaneously in a complex and interrelat-
ed manner. Another mechanism shows that carbon
dioxide is having very high anity for plasma consists
in great part of lipid components. Due to the increased
membrane permeability caused by the reaction of CO2
with water, which lowers the extracellular pH, pressur-
ized CO2 may easily penetrate through the bacterial cell
membrane and accumulate in the cytoplasmic interi-
or of bacterial cells then structurally and functionally
disrupt the cell membrane due to a loss of the order
in the lipid chain If too much dissolved CO2 enters the
cytoplasm, the cells may be unable to expel all the re-
sulting protons and internal pH starts to decrease. If
the internal pH is lowered too much, cell viability will
be impaired leading to inhibition of cell metabolism
or denature certain proteins and enzymes essential for
metabolic and regulatory processes, such as glycoly-
sis, amino acid and peptide transport. Finally internal
damage of the metabolic processes induces microbial
inactivation. Studies on Microbial Inactivation in Liquid
Foods such as Whole skim milk, fruit juices like orange,
peach, carrot, mandarin, watermelon, pear, apple,
grapefruit a well as many harmful enzymes by Dense-
Phase shows 5 to 7 log reduction of Pathogenic bacte-
ria and yeast [77].
Chen J, investigated the eects of DPCD treatment of 8,
15, 22, 30 and 35 MPa for 5, 15, 30, 45, 60 min at 35°C,
45°C, 55°C, 65°C on vitamin C in Hami melon juice dur-
ing storage at 4 0C for 4 weeks. The authors found that
vitamin C concentration decreased following DPCD
processing, but percentage loss was lower than of the
untreated samples. DPCD also appear to prevent losses
of other potential bioactive compounds such as β-car-
otene. The study conducted by Chen J showed better
retention of β-carotene in DPCD (55 0C, 60 minutes, and
35 MPa) treated melon juice compared to convention-
al HTST pasteurization. Signicant losses (57.87%) in
β-carotene content was observed in heat pasteurized
samples. It should be noted that exact mechanism for
β- carotene stability is dicult to establish [78].
Many examples of the applications of the DPCD to juic-
es demonstrated the protective nature of the process
to antioxidants, phytochemicals, organoleptic attrib-
utes such as taste, color, and appearance. The relatively
low process temperatures, the lack of oxygen in the en-
vironment, and for some nutrients, the lower pH, pro-
tect the vitamins such as vitamin C. Since the process
can be made continuous, its control is easy [78].
However this technology is facing some challenges
such as lack of the commercially successful DPCD oper-
ation, higher cost of the operation, stringent environ-
mental regulations regarding the release of CO2 into
the atmosphere, both total capture and recycling of
Journal of Hygienic Engineering and Design
the gas needs to be designed into new systems, or a
carbon-neutral source of CO2 needs to be used, limited
data to satisfy the regulatory requirements [77].
2.3.14 Ultra-sound processing of food
Power ultrasound employed in food processing uses
the lower-frequency ranges of 20 - 100 kHz with a
sound intensity of between 10 and 1,000 W/cm2. The
vibrational energy is provided by ultrasonic transduc-
ers that convert electrical energy to sound energy of
which there are two types in common usage, piezoe-
lectric transducer and magnetostrictive transducers.
The driving force for the processing eects of sonica-
tion is acoustic cavitation. The cavitation bubbles are
generated by the ultrasound wave as it passes through
the liquid. Like any sound wave, it is transmitted as a se-
ries of compression and rarefaction cycles aecting the
molecules of the liquid. When the negative pressure of
the rarefaction cycle exceeds the attractive forces be-
tween the molecules of the liquid, a void is formed. This
void or cavity in the structure takes in a small amount of
vapor from the solution so that on compression it does
not totally collapse, but instead continues to grow in
size in successive cycles to form an acoustic cavitation
bubble. There are many thousands of such bubbles in
a liquid, some of which are relatively stable but others
expand further to an unstable size and undergo violent
collapse to generate temperatures of about 5,000 K
and pressures of the order of 50 MPa. The cavitation
bubbles formed in this way are divided into two types:
Stable cavition and Transient cavitation [79].
For the sterilization of liquid foods, higher acoustic en-
ergies are employed and the approaches can be classi-
ed as sonication alone, manosonication (pressure and
ultrasound), themosonication (heat and ultrasound),
or monothermosonication (heat, pressure, and ultra-
sound). The mechanisms through which ultrasound
aects microbial inactivation are induced by acoustic
cavitation which results in the weaking or disruption
of bacterial cells through various processes. Bacteria
cell wall damage, due to mechanical eects induced
by pressure gradients generated during the collapse of
cavitation bubbles within or near the bacteria. Second
process is shear forces induced by micro-streaming
which occurs in the bacterial cell itself. Third approach
suggest, chemical attack due to formation of free rad-
icals during cavitation which attack the cell wall struc-
ture leading to disintegration. In addition there will be
the formation of a small amount of hydrogen peroxide
via sonication, which itself is a bactericide. One of the
major bactericidal eects of ultrasound is attributed to
intracellular cavitation; that is, micromechanical shocks
that disrupt cellular structural and functional compo-
nents up to the point of cell lysis. Use of ultra-sound
processing for desired microbial reduction is studies
with various food products such as orange juice, apple
cider, mango juice, guava juice, tomato juice, whole
milk, skim milk. In terms of dairy products, especially
milk, ultrasound providing considerable benet at low-
er-temperature pasteurization [80].
Rawson investigated the eect of thermosonication
on the bioactive compounds of freshly squeezed wa-
termelon juice. They observed a higher retention of
ascorbic acid and lycopene at low amplitude level and
temperature. They also observed a slight increase in ly-
copene at low amplitude level [81].
2.3.15 High Voltage Arc discharge
High voltage arc discharge is a method to pasteur-
ize liquid foods by applying rapid discharge voltages
through an electrode gap below the surface of aque-
ous suspensions of microorganisms. When rapid high
voltages are discharged through liquids, a multitude
of physical eects (intense waves) and chemical com-
pounds (electrolysis) are generated, referred to as elec-
trohydraulic shock, which inactivate the microorgan-
isms [82]. Enzymes are also inactivated by high voltage
arc discharges.
Palaniappan and Sastry presented an extensive litera-
ture review on the eect of electrohydraulic shock on
the inactivation of microorganisms. They reported that
bacterial inactivation was not due to heating, but main-
ly to irreversible loss of membrane function as a sem-
ipermeable barrier between the bacterial cell and the
environment and to the formation of toxic compounds
(oxygen radicals and other oxidizing compounds). In
their review, it was concluded that chemical action is
a complex eect and depends not only on the voltage
applied but also on the type of microorganism, initial
concentration of cells, volume of the medium used,
distribution of chemical radicals, and electrode mate-
rial [83].
Inactivation is attributed to oxidation reactions medi-
ated by free radicals and atomic oxygen. There is no
signicant temperature increase during treatment by
arc discharge [84]. Gilliland and Speck found electro-
hydraulic treatment to be eective in inactivating at
least 95% of the vegetative cells of E. coli, Enterococcus
faecalis, Micrococcus radiodurans, Bacillus subtilis and
its spores. High voltage electrical impulses were dis-
charged at a rate of 1 V/s [85].
2.4 Sensitive Nutrients with their food systems
Thus delivery of heat sensitive nutrients through food
systems posed a challenge for food scientist to satis-
fy often conicting requirements with respect to the
incorporation of sensitive active ingredients in food
products of increasing complexity have provoked a
Journal of Hygienic Engineering and Design
growing interest in the development and application
of delivery systems for foodstus. In many cases, how-
ever, it is dicult to apply established encapsulation
technologies without modication to an application of
interest, principally because the physical and chemical
behaviour of the sensitive ingredients and the func-
tionality of the delivery system are poorly understood.
So systematic evaluation of various aspects of food sys-
tems should be done at the time of developing food
systems delivering heat sensitive nutrients. Some ex-
amples of such food systems are described below with
appropriate explanation.
According to FAO/WHO (2004), the recommended in-
take for vitamin A is 375 µg Retinol Equivalent (RE) per
Day (for Infants) upto 600 µg RE per Day (for Adults).
Iron requirements are 4.2 mg per Day (for children)
upto 9.1 mg per day for adult males and 7.5 – 19.6
mg per day for adult females at 15% bioavailability.
Calcium requirements are 500 - 700 mg per Day (for
children), 1000 mg per day for adult males and 1000
– 1300 mg per day for adult females. Vitamin C require-
ments are 30 - 35 mg/Day (for children), 45 mg/day
for adult males and females. The recommended daily
intake (RDI) for Iodine for adult is 100–150 µg/day for
Adults and 90 -120 µg/day for children [86].
2.4.1 Vitamin A, Iron and Iodine:
Rutkowski and Diosady [87], developed a triple for-
tied which contained Vitamin A (250 IU per gram of
salt), Iron (1000 ppm) and Iodine (50 ppm). Vitamin A
is used in the form of vitamin-A palmitate, iron in the
form of ferric NaEDTA and iodine in the form of potas-
sium iodate. Here stability of vitamin A is maintained
by using Shellac as a hydrophobic coating agent. They
also found good stability of vitamin A, Iron and iodine
during processing and storage. Vitamin A is also used
in the form of retinyl acetate at 257.85 µg per 100 g of
cookies and shows minimum losses during baking i.e.
8.69 - 11.11%. It fulls our 45 % RDA of vitamin A [88].
2.4.2 Calcium
Food products nd wide range of calcium fortied food
products in market. Meat sausage fortied with calci-
um lactate and calcium glutamate at concentration
of 27 - 32 mg per 100 g of product [89]. Apple slices
are also impregnated with calcium upto 140 - 250 mg
per 100 gm [90]. Often vitamin C in combination with
calcium fortied in food to enhance the bioavailability
of calcium. Calcium enriched food products contains
wheat our tortillas (48 g per 100 g) [91], mango yogurt
(50 mg per 100 g) [92], soy milk (24.96 - 28.8 mg per
100 g) [93] which provides 20 to 40 % RDA for calcium
(1000 mg per day).
2.4.3 Zinc
Zinc, in the form of zinc sulphate and zinc oxide is
used to fortied parboiled rice at concentration 13.2
- 44.1mg per 100 g [94]. Zinc oxide (30 ppm) in combi-
nation with NaFeEDTA (40 ppm) used in whole wheat
our [95].
2.4.4 Iodine
Potassium iodide is used to enriched salt in combina-
tion of iron (ferrous fumarate) at concentration up to 50
mg per kg. It is also used during manufactured of meat
burger and meat balls with wheat bre and soy isolate
impregnated with KI and KIO3 (43 µg per 100 g) which
provides 30 % RDA (150 µg per day) [96].
2.4.5 Vitamin D
RDA for Vitamin D is 5 µg per day for children, 10 - 15 µg
per day for adult (FAO WHO 2004). It is used to enrich
milk (upto 5000 IU per 100 g), yogurt (5000 IU per 100
g) and ice-cream (5000 IU per 100 g) in the emulsied
form of vitamin D in butter oil [97]. In many countries,
milk, milk products, margarine, vegetable oil fortied
with vitamin D, used as a major dietary source. This
vitamin along with vitamin A and calcium used to
enrich dairy products. This fat soluble vitamin should
not cross the limit of 50000 IU per day through food to
avoid toxic eect.
2.4.6 Vitamin E
The RDA for α - tocopherol is 4 - 15 mg per day for
adults and children. Vitamin E is used to fortify ground
beef pattice (300 ppm)[98]. α – tocopherol succinate
which is heat and storage stable form of vitamin E is
used in soft drinks and ice-crieams. Microdispersion of
vitamin E (alpha-tocopheryl acetate) in milks showed
increased molar ratio of plasma tocopherol to choles-
terol (2 times) compared with Vitamin E capsules [99].
2.4.7 ω-3 long chain PUFA
These are used to fortify yogurt, cream (1 - 5 mg per 100
g). Also in cheese (30 mg per 100 g), processed cheese
(40-60 mg per 100 gm), spreadable fresh cheese (20 mg
per 100 g) [100].
2.4.8 Vitamin C
Ascorbic acid is most heat liable vitamin and also wa-
ter soluble so it is enriched in the combination of iron
in various food systems such as dairy products such as
cheese, yogurt, chocolate milk which increases the bi-
oavailability of iron in presence of vitamin C. It is also
Journal of Hygienic Engineering and Design
Table 3. Sensitive nutrients with their food systems
Sr. No. Chemical form Added concentration Food product References
1. - Calcium citrate
- Calcium lactate
- Calcium gluconate 27 - 32 mg/100 g of product Meat Sausage [89]
2. - Calcium lactate 140 - 250 mg/100 g of product Vacuum impregnated apple slices [90]
3. - Calcium carbonate
- Calcium citrate
- Calcium lactate 48 mg/100 g of product Wheat our tortillas [91]
4. - Calcium lactate 50 mg/100 g of product Calcium fortied cow milk [105]
5. - Calcium lactate pentahydrate 50 mg/100 g of product Mango yogurt [92]
6. - Calcium glutamate 24.96 - 28.28 Soymilk [93]
7. - Dextrin encapsulated
- Potassium iodide
- Ferrous fumarate
KI - 50 mg /100 g
Iodine - 100mg/100g of product Salt [106]
8. - Wheat bre and soy isolate im-
pregnated KI and Potassium iodate
43 µg/100 g
(30 % RDA) Meat burgers and meat balls [96]
9. - Zinc sulphate
- Zinc oxide 13.2 - 44.1 mg/ kg Parboiled rice (polished) [94]
10. - Zinc oxide and NaFeEDTA 30 ppm Whole wheat our [95]
- Ferrous sulphate
- Fe-EDTA 10 - 30 mg/100 g Bakery products- our Bread, Cookies,
Wheat bread
- Ferric pyrophosphate
- Ferrous fumarate 12 mg/L Milk infant formula
- FeCl310 mg Fe/100mL Yogurt
- Caesin-chilated Iron ferric chloride
25 - 50 mg Fe/kg Mozzarella cheese
- Ferrous Sulphate 15 mg/L Milk
Vitamin E
12. - Vitamin E 300 ppm (µl of Vit E/g lipid meal) Ground beef patties [98]
13. - α-tocopherol -
Β-lactoglobuline and Hen egg white protein
Vitamin D
14. - Vit. D3 emulsied in butter oil 5000 IU/100g of product Cheese, Yogurt, Ice-cream [97]
Vitamin A
15. - Retinyl acetate 257.85 µg/100 g Cookies [15]
16. - Vitamin A, palmitate iron and
Vit A - 250 IU of vit.A/100 g
Iron - 1000 ppm
Iodine - 50 ppm Triple fortied salt [87]
17. - Retinol - O/W/O emulsion
18. - Retinol - Glyceryl behenate SLN
19. - All trans retinoic acid - 2-Hydroxypropyl-β-cyclodextrin complex
20. - Retinol - Β-Lactoglobulin complex
Folic Acid
21. - Folic acid (low methoxy pectin
and ethyl cellulose) 400 µg/g Parboiled rice [104]
22. - Folic Acid 0.05 g/100 g of our Asian noodle [110]
23. - Folate
131 - 191 µg/100g Bakery Products, Sourdough, French
loves, Potato rolls, Sandwitch.
33 - 229 µg/100g Cereal products-ours, baking n\mix,
bread mix
154 - 308 µg/100g Instant rice, Parboiled rice yellow rice,
precooked rice.
198 - 264 µg/100g
Enriched macaroni products, Spagetti, Pasta.
198 - 264 µg/100g Noodle
80 - 400 µg/100g
Ready to eat breakfast cereals(corn, oat, wheat)
40 - 120 µg/100g Cereal bars
24. - Riboavin - Soy protein cold set hydrogel [102]
Vitamin C
25. - Vitamin C 33 mg/100 g Ascorbic acid [101]
- Vitamin A palmitate 300 IU/100 g Vit. A palmitate
Nutrients having functional properties
26. - Ω-3 long chain PUFA
1 - 5 mg/100g Cheese, butter
20 mg/100g Spreadable fresh cheese
30 mg/100g Cheese, butter
40 - 60 mg/100g Processed cheese
27. - Curcumin 4.1 mg/mL of lecithin and Tween
80 as the surfactants and ethyl
oleate as oil phase - [111]
Journal of Hygienic Engineering and Design
used to enrich dierent fruit juices which undergoes
minimum heat treatments and retained maximum
quantity of vitamin C [101].
2.4.9 Vitamin B
Vitamin B1 is sensitive to heat or oxidation. The major
challenge in this context is, these are water soluble
vitamins and leaching losses are more. They are often
delivered through breakfast cereals, juices, milk, and
infant formulas. Generally enriched in food products as
vitamin B complex. There are new novel approaches for
delivery of these vitamins such as soya protein cold set
hydrogel is used to entrap vitamin B for incorporation
in food products [102].
2.4.10 Folic acid
Folic acid is soluble in water and sensitive to heat. The
RDA for folic acid is 400 µg per day [86]. Folate is used
to fortify dierent bakery products (Sourdough ban-
quettes, French loves, Buttertop breads, Italian bread,
Potato rolls, Enriched Floors (229 µg per 100g), white
breads upto 131 - 191 µg per 100g ), cereal products
(All purpose ours, wheat our, bread mix, All-purpose
baking mix upto 33-229 µg per 100g), Instant rice
(Precooked rice, parboiled rice, yellow rice, instant rice
at 154 - 308 µg per 100g), macaroni (198-264 µg per
100g), pasta, noodles (198-264 µg per 100g), ready to
eat breakfast cereals (80 - 400 µg per 100g) and cereal
bars (40 - 120 µg per 100g) [103]. Another way of deliv-
ering folic acid is addition to rice up to 400 µg per 100g
of rice and coating with edible polymers ethyl cellulose
Thus dierent combinations of heat sensitive nutrients
and their interaction with each other determine their
bioavailability. Appropriate encapsulation, Use of more
chemically stable form and novel and non-thermal pro-
cessing techniques provides desired retention levels of
sensitive nutrients in Food matrices during processing,
storage and consumption. Following table 3 explains in
details some more examples of vitamins, minerals and
bio-active compounds with respective food systems.
2.5 Recent trends in delivery of heat sensitive nu-
More and more eorts are being taken by food scientist
to incorporate these sensitive nutrients in food by us-
ing newer technologies such as membrane extrusion,
vacuum impregnation. New vehicles for these nutri-
ents such as β-lactoalbumine and Hen white protein
for α-tocopherol, soy protein cold set hydrogel for ri-
boavin, milk caesinates are also developed for protec-
tion against processing conditions [112].
Also biofortication of food plants for vitamins by
using metabolic engineering is also encouraging.
Minerals fortication is done by manipulating manure
dosage during plant growth become more precise and
successful [113].
3. Conclusions
- Food contains many heat sensitive nutrients such
as vitamins, minerals, nutrients having functional
properties. Many processes during manufacturing
of food cause detrimental eects on these nutri-
ents. Among these nutrients vitamins (Vit. A,D,E,
B,C) are most susceptible for heat causes upto 80 %
destruction due to processing treatments and min-
erals get unavailable due to interaction with co-nu-
trients during the heat treatments such as pasteuri-
sation, sterilisation, ultra high temperature.
- In order to maintained the level of these sensitive
nutrients dierent approaches are applied includ-
ing process modications, fortication or encapsu-
lation. The nature of methodology depends exclu-
sively in interest of functionality of particular nutri-
ents in food irrespective of techniques.
- In case of delivery of heat sensitive nutrients
through food systems we concentrate on dierent
delivery systems such as 0/w emulsion, nano-emul-
sions, encapsulation, molecular complexes, and
powder particles with their uses in food application.
- Many recent trends are also becoming more and
more successful to prevent sensitive nutrients from
degradation such as use of: Microwave and Radio
Frequency Heating, Ohmic and Inductive Heating,
High Pressure Processing, Irradiation of Food,
Pulsed X-ray Processing, Pulsed Light processing,
Ultra-Violet Pasteurization, Oscillating Magnetic
Fields, Pulse Electric Field, Chlorine Dioxide
Processing, Low-Temperature Plasma, Ozone pro-
cessing, Dense-Phase Carbon Dioxide Processing of
Fluid Foods, Ultra-sound Processing of Food, High
Voltage Arc Discharge and bio-fortication. Thus
lots of work is to be done by food scientist to come
up with more and more ecient technology.
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... The result showed that emulsification of red palm oil with B. eurycoma or potash followed by drying at 50°C led to reduction in β-carotene content, suggesting that emulsifiers bind β carotene and drying at 50°C resulted in a loss of β carotene. The mechanism of destruction of β carotene has been reported to be through isomerisation (conversion of all trans-β-carotene to stereoisomers having lower pro-Vitamin A activity) during heat treatment (Mahesh & Uday, 2013). Food materials contain many heat-sensitive nutrients. ...
... Cooking conditions and heat treatment caused vitamin loss (Mahesh & Uday, 2013 obtained in this work were higher than the values obtained by Suresh, Samsher, and Durvesh (2015). High WAC of MAFEA may be attributed to increase in amylose leaching, solubility and loss of starch crystalline structure (Suresh et al., 2015). ...
... Nutritional loss during harvest and post-harvest handling is not to be expected. Critically, protein, iron and zinc are neither heat-nor light-sensitive (Deol & Bains, 2010;Satpute & Annapure, 2013). Consequently, sun exposure during postharvest handling activities does not impact their levels. ...
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The reduction of post-harvest losses (PHLs) has been identified as a key pathway to food and nutrition security in sub-Saharan Africa. However, despite policy prioritisation, knowledge about the severity of PHLs remains scant, especially when it comes to nutrient-dense crops such as African nightshade and bush beans. Therefore, this paper identifies loss hotspots, causes and effects throughout the value chains of nightshade and bush beans in eastern Uganda. Primary data collected following the Informal Food Loss Assessment Method, combined with small-scale load tracking and secondary data, allows for an analysis of physical, economic, quality, and nutritional losses throughout the value chains of both crops. Results show that in the bush bean value chain, severe physical and quality losses occur during post-harvest handling by farmers, leading to high economic losses at this stage of the chain. Nutritional losses are not expected to be significant in the bush bean value chain. By contrast, due to the shortness of the nightshade value chain, where produce is moved from harvest to consumption within one or two days, physical losses in most parts of the chain are relatively minor. Only at consumption stage, high physical losses occur. This is also the stage where economic losses and potential nutritional losses are most pronounced. The results of this study offer a deeper understanding of the value chain dynamics of bush beans and nightshade, including underlying gender relations, and identify concrete loss hotspots, upon which further research and practical interventions can build.
... Raw organ meats are dense in vitamins, minerals and trace-minerals and are also a good source of high-quality protein and fat (USDA food composition database). 39 Since some of these nutrients are heat-sensitive, especially the vitamins, 40 offering organs raw to puppies allows them to get the maximum nutritional value. Moreover, raw organ meats as a raw meat-based foods are a good source of beneficial bacteria which may help puppies develop a healthy gut microbiota. ...
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Background The increased prevalence of atopic dermatitis (AD) in dogs necessitates research in its disease etiology. Objectives To explore the association between puppyhood dietary exposures and prevalence of owner-reported allergy/atopy skin signs (AASS) after the age of 1 year. Animals Four thousand and twenty-two dogs were eligible, 1158 cases, and 2864 controls. Methods This cross-sectional hypothesis-driven observational study was extracted from the DogRisk food frequency questionnaire. Forty-six food items and the ratio of 4 major diet types were tested for their association with AASS incidence later in life. Potential puppyhood dietary risk factors for AASS incidence were specified using binary multivariable logistic regression. The model was adjusted for age and sex. Results Eating raw tripe (odds ratio, 95% confidence intervals OR, 95% CI = 0.36, 0.16-0.79; P = .01), raw organ meats (OR, 95% CI = 0.23, 0.08-0.67; P = .007), human meal leftovers, and fish oil supplements as well as eating more that 20% of the diet as raw and/or <80% of the diet as dry, in general, were associated with significantly lower AASS incidence in adulthood. In contrast, dogs fed fruits (OR, 95% CI = 2.01, 1.31-3.07; P = .001), mixed-oil supplements, dried animal parts, and dogs that drank from puddles showed significantly higher AASS incidence in adulthood. Conclusions and Clinical Importance Puppyhood exposure to raw animal-based foods might have a protective influence on AASS incidence in adulthood, while puppyhood exposure to mixed oils, heat processed foods and sugary fruits might be a potential risk factor of AASS incidence later. The study suggests a causal relationship but does not prove it.
... Dietary fibers, also called prebiotics, are nondigestible carbohydrates responsible for maintaining normal intestinal homeostasis through encouraging bacterial diversity, protecting mucosal barriers, and increasing the synthesis of short chain fatty acids (76,77). Furthermore, the processing methods, which the UPCD or their ingredients, are exposed to, such as rendering, milling, fermentation, heat treatment, and extrusion negatively affects the bioavailability of key minerals and vitamins present in the diet (78,79). Feed additives, e.g., dietary emulsifiers which are used to improve kibble texture have been found to contribute to the increased incidence of inflammatory diseases both by reducing the gut microbiota diversity and by reducing the thickness of the mucus layer (80). ...
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Background: Inflammatory bowel disease (IBD) is an idiopathic multifactorial disease in humans and dogs, usually assigned to the interactions between genes, gut microbiota, diet, environment, and the immune system. We aimed to investigate the modifiable early life exposures associated with IBD in dogs. Materials and Methods: The study data was extracted from the validated owner-reported DogRisk food frequency questionnaire. This was a cross-sectional questionnaire-based study that tested 21 different early life dietary and environmental, demographic and genetic variables for their association with IBD or not, in adult dogs. A total of 7,015 dogs participated in this study. The study covered early life periods; prenatal, neonatal, early, and late postnatal periods. Two feeding patterns, a non-processed meat-based diet (NPMD) and an ultra-processed carbohydrate-based diet (UPCD) were studied. Data was analyzed using logistic regression analysis with a backward stepwise deletion. Results: From the final models we found that the NPMD during early and late postnatal periods were significantly associated with lower IBD risk later in life. The UPCD during the same periods was associated with a higher risk of IBD incidence. Also, the maternal diet during the neonatal period showed a non-significant trend of lower IBD risk in the offspring with the NPMD and a higher IBD risk with the UPCD. Additionally, the normal body weight of puppies during the first 6 months of age was associated with a lower risk of IBD in adulthood while, slim puppies associated significantly with IBD in adulthood. From the non-modifiable background variables, we identified the maternal history of IBD as the strongest risk factor for later incidence of IBD. Furthermore, male dogs were twice as likely to develop IBD as female dogs were. Conclusions: It is reassuring for owners to know that they themselves can have an impact on their dog's health. A high-fat, low-carbohydrate NPMD exposure during early life, and a normal body condition in puppyhood were significantly associated with less IBD in adult dogs. The opposite was true for UPCD exposure and abnormal body condition score in 6 month old puppies.
... 42%) of phenolic compounds in spray-dried grape pulp containing gum Arabic and bamboo fiber at 120 °C inlet air temperature. The high temperature during spray drying results in the degradation of encapsulated heat-sensitive compounds such as carotenoids, lycopene, thereby lowers its antioxidant capacity [250]. Additionally, the wall materials are mainly carbohydrates having low glass transition temperature and change their state from glassy to rubbery during spray drying that forms highly sticky powder [251]. ...
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The by-products generated from the processing of fruits and vegetables (F&V) largely are underutilized and discarded as organic waste. These organic wastes that include seeds, pulp, skin, rinds, etc., are potential sources of bioactive compounds that have health imparting benefits. The recovery of bioactive compounds from agro-waste by recycling them to generate functional food products is of increasing interest. However, the sensitivity of these compounds to external factors restricts their utility and bioavailability. In this regard, the current review analyses various emerging technologies for the extraction of bioactives from organic wastes. The review mainly aims to discuss the basic principle of extraction for extraction techniques viz. supercritical fluid extraction, subcritical water extraction, ultrasonic-assisted extraction, microwave-assisted extraction, and pulsed electric field extraction. It provides insights into the strengths of microencapsulation techniques adopted for protecting sensitive compounds. Additionally, it outlines the possible functional food products that could be developed by utilizing components of agricultural by-products. The valorization of wastes can be an effective driver for accomplishing food security goals.
... The effect of the diet on allergy development depend on the kind of the diet, some diets are protective while others are a risk of allergy development [78]. Heat processing of UPCD has been shown to destroy nutrients, active enzymes and antioxidants, making it non-nutritionally sound [79]. Indeed, heat processing boosts the denaturation of food proteins, which interact with other food components, promoting immunogenicity and allergenicity [44]. ...
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A cross-sectional hypothesis generating study was performed to investigate modifiable exposures such as whether feeding pattern (a non-processed meat based diet, NPMD, or an ultra-processed carbohydrate based diet, UPCD), certain environmental factors and their timing of exposure might be associated with the development of canine atopic dermatitis (CAD). Also, genetic and demographic factors were tested for associations with CAD. The data was collected from the validated internet-based DogRisk food frequency questionnaire in Finland. A total of 2236 dogs were eligible for the study (the owners reported 406 cases and 1830 controls). Our main interest was to analyze modifiable early risk factors of CAD, focusing on nutritional and environmental factors. We tested four early life periods; prenatal, neonatal, early postnatal and late postnatal periods. Twenty-two variables were tested for associations with CAD using logistic regression analysis. From the final models we identified novel dietary associations with CAD: the NPMD during the prenatal and early postnatal periods had a significant negative association with the incidence of CAD in adult dogs (age above 1 year). Oppositely, UPCD was associated with a significantly higher risk for CAD incidence. Other variables that were associated with a significantly lower risk for CAD were maternal deworming during pregnancy, sunlight exposure during early postnatal period, normal body condition score during the early postnatal period, the puppy being born within the same family that it would stay in, and spending time on a dirt or grass surface from 2 to 6 months. Also, the genetic factors regarding maternal history of CAD, allergy-prone breeds and more than 50% white-colored coat all showed a significant positive association with CAD incidence in agreement with previous findings. Although no causality can be established, feeding NPMD early in life seemed to be protective against CAD, while UPCD could be considered a risk factor. Prospective intervention studies are needed to establish the causal effects of the protective role of NPMD on prevalence of CAD during the fetal and early postnatal life.
... The ash content of all treatment is higher compared to fresh goat milk, as agreed in previous study (Filiz, 2013). Unlike vitamins, mineral is less sensitive to physical and chemical factors (Satpute and Annapure, 2013). Data are means of triplicates ± SEM. ...
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Spray drying is a method of drying powder via microencapsulated from liquid rapidly with hot temperature in order to increase the shelf life. Hence, the objectives of the study are to investigate the effect of spray drying temperature on the nutritional composition and physical properties of dry milk powder of Saanen goat milk reared in Sandakan using maltodextrin as binder. The experiment tested the inlet air temperature variation from 140°C - 220°C with triplicates. The result was analyzed by a one-way analysis variance (ANOVA) using the Statistical Analysis System (SAS) version 9.4. The results showed that there are significant (p<0.05) effects of inlet air temperature on dry milk powder in term of its protein content, fat content, moisture content and the sinkability of the milk powder. Among all of the treatments, the most sinkable temperature was at 140°C. Overall, the control powder, T0 = 180°C, however, is still preferable as nutritional value (for both protein and fat) shown to be higher in this powder and have acceptable moisture and physical properties. The finding of this study can be modified as for further investigation to improve the quality of milk powder in term of its nutritional value and physical properties. J. Bangladesh Agril. Univ. 17(2): 206–210, June 2019
... Thus, vitamins are unstable in food and dependent on specific parameters such as the cooking time or time of exposure to the method, pH, temperature, and among others. The water-soluble vitamins are labile to any process technique, and the fat-soluble vitamins are destroyed by the radiation methods [46][47][48]. ...
Full-text available
Generally, foods are thermally processed to destroy the vegetative microorganisms for food preservation. However, only thermal treatment triggers many unwanted biochemical reactions, which leads to undesirable sensorial and nutritional effects. Therefore, a number of nontraditional preservation techniques are being developed to satisfy consumer demand with regard to nutritional and sensory aspects of foods. Ensuring food safety and at the same time meeting such demands for retention of nutrition and quality attributes has resulted in increased interest in emerging preservation techniques. These emerging food preservation technologies can extend the shelf life of unprocessed or processed foods by inactivating the enzymes, reducing the food spoiling microbial growth rate or viability without altering the food quality attributes including flavor, odor, color, texture, and nutritional value. On the emerging technology, sphere promising results have been attained by the radiation processes. Ionizing radiation has been widely used in industrial processes, especially in the sterilization of medicals, pharmaceuticals, cosmetic products, and in food processing. Nonionizing radiation has been used in surface decontamination, as on the packaging sector. Although radiation techniques, as the other traditional or emerging techniques, can impair alterations that can modify the chemical composition and the nutritional value of foods, these changes depend on the food composition, the irradiation dose and factors such as temperature and presence or absence of oxygen in the irradiating environment. The aim of this chapter is to discuss retention or loss of vitamins and minerals in several food products submitted to a radiation process (gamma irradiation, short wave ultraviolet, microwave, and pulsed electric fields).
The present study investigated feedforward‐backpropagation ANN architectures to predict sensory scores at different moisture levels (40‐50%) of paneer. Paneer was produced aseptically and packed in LDPE bags, in a semi‐organized commercial dairy plant. Samples were evaluated at regular intervals (8 days) for biochemical content and microbial counts, while subjected every day for sensory evaluation. Three layered (Input‐hidden‐output) ANN was able to produce similar sensory responses using biochemical and microbiological data, for both single (best combination 10‐7‐1; R2 ≈ 0.99) and conjugated (10‐9‐4; R2 ≈ 0.97) parameters for an extent of 25 sensory output nodes (10‐35‐25; R2 ≈ 0.90). The comparison of ANN and predicted sensory scores using linear regression model (with R2 = 0.99) suggests, paneer at 42‐44% and 47‐49% moisture was best for consumption as fresh and for storage. The developed method for predicting and analysing sensory data of produced paneer, opens new possibilities for improving food product’s likeness.
The food-processing industry has made large investments in processing facilities relying mostly on conventional thermal processing technologies with well-established reliability and efficacy Food contains many heat sensitive nutrients which include vitamins, minerals, and nutrients having functional properties such as pigments, antioxidant, Bioactive compounds. Many processes during manufacturing of food cause detrimental effects on these nutrients. Retention of these nutrients in food products requires innovative approaches for process design because of their sensitivity to a variety of physical and chemical factors, which causes either loss of biological functionality, chemical degradation and premature or incomplete release. Alternative methods for thermal processing of food are gaining importance, due to increased consumer demand for new methods of food processing that have a reduced impact on nutritional content and overall food quality. Also as a result of the increasing consumer demand for minimally-processed fresh-like food products with high sensory and nutritional qualities, there is a growing interest in non-thermal processes for food processing and preservation. Non-thermal food processing/preservation methods interest food and food packaging scientists, manufacturers and consumers because they exert a minimal impact on the nutritional and sensory properties of foods, and extend shelf life by inhibiting or killing microorganisms. They are also considered to be more energy efficient and to preserve better quality attributes than conventional thermally based processes. Non-thermal physical processes are evolving as potential alternatives to thermal and chemical unit operations in food processing. Non-thermal methods allow the processing of foods below temperatures used during thermal pasteurisation, so flavours, essential nutrients, and vitamins undergo minimal or no changes. These processes also meet industry needs by offering value-added products, new market opportunities and added safety margins.
Dramatic changes in the attitudes toward human nutrition have taken place dur­ ing the past decade. Food-related and medical professionals as well as consumers are now, more than ever before, aware of and concerned about diet, nutrition, and the beneficial and deleterious effects of food processing upon nutrients. The old saying "We are what we eat" is still relevant. Nutritious food will contribute greatly to consumers' good health and ultimately reduce medical bills. Food processing is essential to maintaining our food reserves from one harvest to another, thus letting us serve our daily meals regularly. If food processing is defined as including all treatments of foodstuffs from harvest to consumption, then more than 95% of our food may be considered as processed. In most cases, food processing and storage cause some reduction in the nutritional value of foods. Advances in food science and food technology have resulted in an increase in nu­ trient retention after processing. In addition, today's consumer better understands how to avoid excessive nutrient losses during food preparation. The information presented in this completely revised reference and textbook will help the reader to understand better the relationship between food processing and nutrient retention. The authors' scholarly contributions are greatly appreciated.
Nutrients are destroyed when foods are processed largely because they are sensitive to the pH of the solvent, to oxygen, light and heat, or combinations of these. Trace elements, especially copper and iron, and enzymes may catalyze these effects.
We developed a pilot-plant nonthermal flow process using microwave energy to inactivate microorganisms. The process consists of multiple passes through the microwave generator. Each passed material goes to a receiving tank for subsequent passes. The Bow rate was 0.96 to 1.26 kg/min and the dwell time per pass was 1.1 to 1.5 min. Five passes were used. The microwave energy is instantaneously and simultaneously applied to the system, and thermal energy is removed by a fooling tube within the process Line in the microwave generator. The cooling tube maintains the temperature below 40 degrees C. There was significant reduction in microorganisms in water, 10% glucose solution, and apple juice, and in yeast in beer. There was a slight decrease in microorganisms in tomato juice, pineapple juice, apple cider, and beer; and no effect in skim milk.
Conference Paper
The ability of a cell, tissue, or organism to better resist stress damage by prior exposure to a lesser amount of stress is known as adaptive response. It is observed in all organisms in response to a number of different cytotoxic agents. One of these agents, oxidative stress, is known to induce an adaptive response in bacteria that is accompanied by the induction of many proteins. De novo protein synthesis is required for adaptive response to oxidative and other types of stress, indicating that newly synthesized protective proteins are necessary for adaptation. Adaptive response to oxidative stress also has been observed in mammalian cells. Several studies suggest it is necessary to first preexpose mammalian cells to a somewhat toxic oxidative stress in order to observe significant resistance to a subsequent highly lethal dose of oxidant. Cross-resistance of oxidatively stressed cells to other toxic agents including gamma- and X-irradiation, heat shock, aldehydes, heavy metals, MNNG, N-ethylmaleimide, and heme also has been reported. Understanding oxidant adaptive response in more detail and identifying the protective proteins involved may prove to be of clinical benefit.
Cyclodextrins are cyclic oligomers of glucose that can form water-soluble inclusion complexes with small molecules and portions of large compounds. These biocompatible, cyclic oligosaccharides do not elicit immune responses and have low toxicities in animals and humans. Cyclodextrins are used in pharmaceutical applications for numerous purposes, including improving the bioavailability of drugs. Current cyclodextrin-based therapeutics are described and possible future applications discussed. Cyclodextrin-containing polymers are reviewed and their use in drug delivery presented. Of specific interest is the use of cyclodextrin-containing polymers to provide unique capabilities for the delivery of nucleic acids.