The investigation of the commercial and processing feasibility of the dairy products
The investigation of the commercial and processing feasibility of the dairy products
contents
. Introduction:
.1 Aims
.2 Objectives
.3 Background
.3.1 Traditional dairy products
1.3.2 World markets of dairy products
2. Some aspects needed to be improved to satisfy the demands of
consumers and manufacturers
2.1 The trend in developed countries
2.2 The trend in developing countries
3. Developments of new strategies:
3.1 Whey processing
3.2 Fat adjustment
3.3 Probiotics
4. Outlining newly developed techniques used in innovative
strategies
4.1 Ultrafiltration
4.2 Dialysis
4.3 Immobilised enzyme system used in lactose hydrolysis
4.4 Ultra High Temperature (UHT) treatment
4.5 Vegetable and marine oils blending with milk fat in fat spreads
4.6 Milk fat fractionation
5. Quality and safety issues associated with the new strategy----case
study: yogurt
5.1 Quality and safety of yogurt
5.2 Commercial prospects and yogurt derivatives:
6. Conclusion:
7. References:
. Introduction:
Aims:
? To identify a range of milk sourced products and associated processing procedures.
? To critically evaluate the commercial and processing aspects relevant to varieties of the
traditional dairy products.
? To investigate the feasibility of the innovative strategies on dairy products.
1.2 Objectives:
? To identify factors influencing the quality and safety aspects of a range of dairy
products.
? To identify the market capacity of those newly developed products through
comparisons with traditional dairy products.
? To identify various processes consistent with those innovative strategies.
.3 Background:
.3.1 Traditional dairy products:
Generally, traditional dairy products can be simply classified into four major groups: liquid
milks, fermented milks, concentrated high fat content milks and concentrated dried milks.
In terms of the liquid milk products, the markets mainly focus on the pasteurized whole or
skimmed milk. Normally, the raw fresh milk would be collected from the farm and further
treated in the dairy. The major handling procedures include heat treatment (pasteurization is
the most popular method, by which the milk would be heated to 72°C for 15 seconds),
homogenization and removal the fat, if skimmed liquid milk was questioned.
Maybe fermented milks ought to be regarded as the most important group in total dairy
products, since these products have occupied the majority of the world market space and
were expected as the most promising dairy products in future. Cheese and yogurt are the
typical examples of fermented milk products. Because their "healthy image", cheese and
yogurt have been accepted by most consumers for many years. The main manufacture
procedures that made them differentiated from other dairy products comprise: 1. Inoculating
the culture microorganisms, dependent on the desired characteristics, bacteria or fungi. 2.
Coagulating or aggregating the solid content and consequently developing the characteristic
flavor and texture by organisms or the enzymes added.
Butter is normally looked as the typical concentrated high fat content milk, according to the
standard of FAO/WHO, the fat content should be adjusted to at least 80%(Pak 1995).
Butter or other high fat content milk products have always been produced by churning, by
which the fat content would be elevated to the required level and the texture would be
changed.
Concentrated dried milks are largely consumed in developing countries, while in developed
areas these products are mainly used as the food ingredients. The most common treatment is
spray drying method, by which the water content are removed from milk basis.
.3.2 World markets of dairy products:
In Europe and North America, consumers show an increasing preference for so-called
"light" products. A further diversion of the consumption habits towards fermented and
flavored milks has been steadily increased. The consumption of whole milk was gradually
decreased while the skimmed and fermented milk products have increased, though also in
low speed. Generally, the milk consumption in most developed countries seems to be
stagnant (Bulletin 1988.; Early 1998).
In terms of the global markets, the major consumption growth is reported for Asia. It was
estimated that this growth mainly resulted from the consumption of liquid milks and
concentrated dried milk products though the consumption of other milk products has also
increased. In other areas of the developing world, especially where local fresh milk
production is inadequate, condensed and dried milk consumption continued to
increase(Robinson 1994).
If the whole picture of the milk market is considered, it may be expected that the rapid
growth of urban populations in developing countries, development of consumption structure
and the evolution in the market system will further change the producing and processing
technologies.
2. Some aspects needed to be improved to satisfy the demands of
consumers and manufacturers
2.1 The Trend in developed countries.
In last several decades, "healthy foods" have attracted more attention in developed
countries. Followed with the changes in lifestyle, food technology and theories of nutrition,
"healthy or high nutritive value" has become the most important character of the dairy
products (Hui 1993; Robinson 1994). As the result, the market requires much more
innovative strategies to improve those relevant quality parameters. Though it's impossible to
find out all the aspects concerned by consumers or manufacturers, some major contributory
factors are listed in table I.
Table I Trends in improving the quality in a range of dairy products
Trends in improving the quality
Typical dairy products
Reduce fat content
Butter and mixed fat spreads
Improve Spreadability
Butter and mixed fat spreads
Reduce ...
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products (Hui 1993; Robinson 1994). As the result, the market requires much more
innovative strategies to improve those relevant quality parameters. Though it's impossible to
find out all the aspects concerned by consumers or manufacturers, some major contributory
factors are listed in table I.
Table I Trends in improving the quality in a range of dairy products
Trends in improving the quality
Typical dairy products
Reduce fat content
Butter and mixed fat spreads
Improve Spreadability
Butter and mixed fat spreads
Reduce the content of SFAs
Butter and mixed fat spreads
Fortification of nutritive value
Cheese
Adding flavours
Yogurt
Adding probiotics
Yogurt
Prolong the shelf life
Liquid milks
Crystallization lactose
Virous dairy products
Hydrolysis lactose
Various dairy products
2.2 The trend in developing countries:
As mentioned in the section 1, the characters of the market in developing countries are
different from that of the developed countries. As the same time, those differences were
reflected in the market capacities and technological strategies. A good example is presented
for pasteurization. It's well known that pasteurization process will inevitably destroy certain
milk components. Although these nutritive damage are always overwhelmed by safety and
quality considerations in developed country, it need to be improved in most developing
countries since milks are normally regarded as high nutritive value food to supplement the
daily nutrition intake. Therefore, fortification of vitamins, minerals, or protein content into
various products may need to be taken into account. Additionally, because of other
contributory factors such as policies or regulations, diabetic tradition and religion, extending
the shelf life, altering processing formula, changing the typical sensorial characters may be
required.
3. Developments of new strategies:
3.1 Whey processing:
The topic of whey utilization has had great importance to the dairy industry, since some
major products may have static or declining market, this importance is likely to increase. It
was reported by IDF 1988 that about 12% of the solids present in world milk production
would be finished in whey basis (Bulletin 1988.). This huge economic potential predicts that
whey utilization will be the greatest challenge in dairy industry. On the other standpoint, the
demand for reducing pollution resulting from discharges from cheese and casein operations
is also an important factor promoting the development of whey utilization (Early 1998).
Probably the single most important change in whey processing is the application of
ultrafiltration, which provided an efficient way to abstracting protein and improve the quality
of subsequent products (e.g., cheese). Additionally, other techniques have also been applied
in this field, for example, ion exchange, dialysis and reverse osmosis (Bulletin 1988.). In
terms of lactose utilization, if looked as a special part of whey processing, the techniques are
mainly focus on hydrolysis or crystallization of lactose. The manufacture methods include
enzyme hydrolysis, acid hydrolysis and hydrogenation.
3.2 Fat adjustment
Fat plays an important role in a wide range of dairy products. It not only participates in the
formation of texture, flavor, aroma and color, but also influences the spreadability, spattering
properties and nutritive value of dairy products (Hui 1993; Early 1998). Apparently, the
content, composition and existing phase of fat in milks will eventually determine those
associated characteristics. Generally, those adherent natures of fat can be adjusted by
manipulation of the cow's diet, fractionation of fat, increasing moisture content, increasing
aeration or changing the processing techniques (Robinson 1994).
3.3 Probiotics:
Probiotics, as functional agents, are widely used in cultured milk products (e.g.,yogurt). The
living bacteria retained in the intestine alleviate lactose maldigestion, maintain the normal
intestine micro flora and prevent the infection of the pathogenic bacteria, and these were
deemed as the anti-carcinogenic, serum cholesterol levels reducing and the effects of renal
malfunction alleviating agent. However, the claimed effects, are by no means fully
documented. Occurently, the most commonly used microorganism are lactococcus casei
spp casei, Bifidobacterium specises bifidum, infantis, breve, longum and adolescentis
(K 1991; H and P 1994; Chandan 1999).
4. Outlining newly developed techniques used in innovative
strategies
4.1 Ultrafiltration:
Ultrafiltration is a sieving process that employs a membrane (normally synthetic polymers)
with definite pores (normally the pore diameters ranging from 1-35 nm) that are large
enough to permit the passage of water and small molecules. When pressure is applied to a
fluid, the semipermeable membrane allows small species to pass through as permeate and
larger species are retained and concentrated as retentate. In ultrafiltration of milk, nonprotein
nitrogen and soluble components such as lactose, salts, and some vitamins pass through the
membrane, whereas milk fat, protein, and insoluble salts are retained by the membrane
(Bulletin 1988.; Hui 1993).
The main advantages of this method are:
? Substantial increase in yield since whey protein and minerals inclusion.
? Simple, continuous process open to almost complete automation.
? Reduction in cheese cost since the cost of energy, equipment, and labor is reduced.
? The process uses substantially less salt and rennet.
The main disadvantages are:
? Cheese becomes very homogeneous and has a high bulk density.
? The acidification is slow for high buffer capacity.
? Very viscous retentate is difficult to mix with starter and rennet, and can't be cooled
without solidification.
? Cheese does not correspond to its definition in properties.
4.2 Dialysis:
Dialysis is a technique employing the difference in concentration as a driving force to
separate large particles from small ones in a solution, for example, proteins from salts. The
rate of diffusion varies with the difference in concentration, so dialysis can be speeded up if
the solvent on the other side of the membrane is changed often (Pak 1995).
4.3 Immobilized enzyme system in lactose hydrolysis
Immobilization techniques are widely used in lactose industry. The principle of this technique
is to fix the enzymes to an inert support. The immobilization procedures employed include
adsorption, entrapment and covalent linkage. By this technique, the overall efficiency has
been greatly increased, and the purity of the end products improved (Bulletin 1988.).
4.4 Ultra High Temperature (UHT) treatment:
UHT treatment has been employed in dairies to produce long life milks. Normally, the
products will be heated to 135-150°C for 4-15 seconds followed by aseptic packaging in
packages protecting the product against light and atmospheric oxygen. Compared with
traditional sterilization in hydrostatic towers, UHT treatment of milk saves time, labor, energy
and space while may introduce "cooked flavor" into the products and sometime changes the
color and nutritive value. Fortunately, many studies are carrying on to find the more efficient
way to organize the temperature and time system to minimize the undesirable effects (Pak
995; Early 1998).
4.5 Vegetable and fish oils blending with milk fat in fat spreads:
Because of the increasing use of prepared foods and heightened health-consciousness, the
pattern of edible fat consumption has shifted from butter to blended fat products (e.g.,
margarine). The general advantages of blending are the products will be easier to spread at
refrigerator temperature without sacrificing the taste of the parent products. Additionally, the
fatty acid composition of fat fractions will be changed. Particularly sn-6 group unsaturated
fatty acids content will be increased, hence then the nutritional value elevated (Hui 1993;
Early 1998).
4.6 Milk fat fractionation:
If the opposite approach to fat crystallization for butter making is applied, for example, very
slow cooling of bulk liquid fat to a few degrees below its melting point, as the result, fat
fractions can be separated. Furthermore, the processes of the fat fractions with a melting
point close to the fractionation temperature will be continued at increasingly low
temperatures to yield further sets of fractions (Early 1998). Dry fractionation (e.g., Tirtiaux
process) is the most common method and regarded as the most favorable method for milk
fat, since its "additive free" nature is in keeping with the "natural" image of milk fat. In
addition, the other techniques used in fat fractionation include solvent fractionation and
detergent fractionation. There is also an innovative technique involving in the fat
fractionation-super critical carbon dioxide extraction, whereas it has not been used
commercially (Early 1998).
Table II
Some important parameters responsible for the spreadability
Different conditions
Solid fat content
For optimum spreadability from the refrigerator
30-40% at 5°C
For good "stand up" and resistance to oiling off at room
temperature
0-20% at 20°C
For clean melting in the mouth
<3% at 35°C
Source from: Ralph Early 1998
5. Quality and safety issues associated with the new strategy
Case study ---- yogurt
5.1 Quality and safety of yogurt
The factors affecting the quality of yogurt are choice of milk, milk standardisation, milk
additives, deaeration, homogenisation, heat treatment, choice of culture, culture preparation
and plant design (Pak 1995). This investigation mainly focuses on the processing and
formulation respects. In order to obtain a greater understanding of the factors that could be
detrimental to end product quality, the role of the fat content, the processing factors
associated with the sensory quality, the microorganisms including starter will be outlined.
? Fat is no doubt the most important single component in many milk based products
including yogurt, since more and more consumers considered high fat content in food
has adverse effect on health. However, It is still a crucial factor contributes to
creaminess and mouth feeling, and also to the stability, structure and aroma. As
mentioned above, for the continuing healthy awareness of the consumers on the fat
content, total fat content is usually standardized to ensure the legal requirements
(minimum requirements of 8.5% milk solids) or to satisfy the consumer demands. In this
practice, the fat content is reduced by addition of skim milk powder (Tamime,
Robinson et al. 1999).
? Homogenization is an indispensable process in yogurt making. The physical-chemical
changes caused by homogenization of milk comprised by the decreasing of fat globule
size, destabilizing of proteins, reduction of the syneresis level, increase the viscosity of
end product, fortification of the white color, elevating the mixing of the skim milk
powder and alleviating the oxidized flavor (Pak 1995).
? Heat treatment has several functions includes destroying the undesirable microorganisms
which may constitute of health hazards or microflora competing with the lactic acid
bacteria in subsequent fermentation, inactivating the autolytic enzymes, producing
stimulatory/inhibitory factors, denaturing the milk proteins and affecting the physical
properties of the gel (Hui 1993).
? Milk bases required free of the pathogenic microorganisms and other foreign particles
including the antibiotics. In yogurt industry, the relatively lower end pH value ensures
that most pathogenic microorganisms will be destroyed or be inhibited, while the fungi
and some acid resistant bacteria may be the most important spoilage hazard sources. It
was believed that the fruit added is an important source of these undesirable
microorganisms (Early 1998).
? Fruits as the flavour elevating ingredients are usually added to yogurt after cooling of the
fermented yogurt and prior to filling in retail container, therefore, the quality of fruits
intimately related to the quality of the end products. There are evidences that the fruits
added to the fermented yogurt always correlate with the spoilage of these products
(Pak 1995).
? As the metabolite product of starter culture, Lactic acid present in yogurt is desirable
for many reasons. Generally speaking, it contributes to the preservation, ease digestion
and the formation of characteristic flavor and texture (H and P 1994; Chandan 1999;
Tamime, Robinson et al. 1999).
Typical HACCP process flow diagram for production of yogurt
? Reception and storage of Raw materials------ccp2
? Standardization and fortification
? Homogenisation------ccp2
? Heat treatment--------ccp2
? Cooling----------------ccp2
? Inoculation------------ccp1
? Cooling----------------ccp2
? Pakaging--------------ccp2
? Incubation
? Chilling/cooling------ccp2
? storage
5.2 Commercial prospects and yogurt derivatives:
Traditional disturbed type fruited yogurt is still the most popular and with "luxury" and
"low fat " yogurts, occupies approximately 70% of the market place in UK. It was reported
by MAFF 1995 that yogurt consumption approximates to 5.3kg/yr per head of UK
population, while in terms of the yogurt markets in other countries, annual per capita
consumption was listed in table III.
Table III consumption of yogurt in certain countries in 1988
Country Annual Per Capita consumption Annual Total consumption
(kg) (1000 Tons)
Austrilia 3.6 60.8
Austria 7.2 54.2
Belgium 6.9 68.3
Canada 3.3 86.6
Denmark 7.8 39.8
Germany(west) 10.8 638.0
Iceland 8.6 2.1
India 4.3 3410.0
Israel 9.4 41.8
Italy 2.4 135.0
Japan 3.8 465.0
Netherlands 18.2 278.5
Norway 4.3 18.0
South Africa 1.6 47.2
USA 2.3 517.9
Source: Y. H. Hui 1993 adapted from International Dairy Federation 1990
It can be seen from the table, the consumption of yogurt constitutes a remarkable share of
the total dairy products market, and there still are potentials in yogurt market not only in the
developed countries but also in some developing countries. It was predicted that the recent
world marketing strategy would focus on the lower fat content, niche product, and more
important, the "bio" yogurt. In 1994, reported £35 million had consumed in UK on the "bio"
type yogurt (Ralph Early 1998). It would be expected an increase will occur in coming
years. It also was believed by Chandon et al (1999) that fluid milk and several dairy
products are an excellent medium to generate an array of products that fit into the current
consumer demand for health-driven foods. It is evident that there is scope for many
companies to make use of this fact and add value to their existing products and/or enter the
market with a new concept. Among these, a product called BRA milk, for example, was
recently introduced on the Swedish market (Pak 1995).
6. Conclusion:
Followed with the changes of direct or potential demands of consumers and manufacturers,
more innovative strategies are required to improve the quality and safety issues of the dairy
products. From the arguments provided above, one can say that it's sensible to invest on the
developments of new strategies about innovative dairy products or innovative processing
techniques. The great market potential in both developed and less developed areas predicts
that the innovative products will play a more important role in the dairy industry in future.
Although some innovative techniques are still not suitable for commercial application and
further investigation on specific market's capacity are needed to be carried out, development
and management on certain innovative strategies are believed of great profitability.
7. References:
A. Y. Tamime and R. K. Robinson. 1999. Yoghurt Science and Technology. 2th edition.
Woodhead Publishing Ltd and CRC Press LLC. Cambridge.
Byron H. Webb, Earle O. Whittier. 1970. Byproducts from milk. The avi publishing
company. Westport.
Chandan. R.C. Enhancing market value of milk by adding cultures. Journal of Dairy
Technology. 50.1.1997
IDF Bulletin. 1988. Trends in utilization of whey and whey derivative. IDF. Brussels.
Orihara. O, Sakauchi.I and Nakazawa.Y. 1992. Types and standards for fermented milks
and lactic drinks. In: Functions of fermented milk. Challenges for the health sciences.
Ed Nakazawa. Y and Honoso. A. Elsevier applied science.
Ralph Early. 1998. The technology of dairy products. 2th edition. Blackie Academic &
Professional. London.
R. K. Robinson. 1994. Modern dairy technology. Advances in milk processing. Volume
. Chapman& Hall. London
R. K. Robinson. 1994. Modern dairy technology. Advances in milk products. Volume 2.
Chapman& Hall. London
Robinson, R.K. 1991. Therapeutic properties of fermented milks. Elsevier applied
science, London.
Tetra Pak. 1995. Dairy processing handbook. Tetra Pak Processing Systems AB. Lund.
Varnam, A.H and Southland, J,P. 1994. Milk and milk products. Technology, chemistry
and microbiology. Chapman & Hall, London
Y. H. Hui. 1993. Dairy Science and Technology Handbook volume 2: Product
Manufacturing. VCH Publishers. Cambridge.
Bulletin, I. (1988.). Trends in utilization of whey and whey derivative. Brussels, IDF.
Chandan, R. C. (1999). "Enhancing market value of milk by adding cultures." Journal of
Dairy Science 82(10): 2245-2256.
Fluid milk and several dairy products are an excellent medium to generate an array of
products that fit into the current consumer demand for health-driven foods. Several
technologies associated with culture addition, fermentation, or both are available for creating
an assortment of flavors and textures in milk products. It appears that accentuating the
positive attributes of inherent milk constituents, incorporating health- promoting cultures, and
offering a variety of flavors and textures to the consumer could enhance milk consumption.
Recent advances in probiotic research show much promise in new product development of
functional foods based on milk. Several scientifically sound clinical studies have verified
some of the anecdotal reports of the past. Among the reported beneficial effects of
consuming certain strains of cultures, or their metabolites, or both are enhanced immune
response, balancing of colonic microbiota, vaccine adjuvant effect, reduction of fecal
enzymes implicated in cancer initiation, treatment of diarrhea associated with travel,
antibiotic therapy, control of rotavirus and Clostridium difficile, control of ulcers related to
Helicobacter pylori, reduction of serum cholesterol, antagonism against food-borne
pathogens and tooth decay organisms, and amelioration of lactose malabsorption symptoms.
The mode of action in most cases seems to involve modulation of ecosystem of the
gastrointestinal tract of the host. Several strains belonging to genera Enterococcus,
Lactobacillus, and Bifidobacterium, which have desirable clinical benefits, are now available.
They are being incorporated in yogurts, dairy snacks, breakfast foods, drinks, refrigerated
desserts, cheeses, spreads, frozen desserts, and unfermented sweet cultured milk.
Early, R. (1998). The technology of dairy product. London, Blackie Academic &
Professional.
H, V. A. and S. J. P (1994). Milk and milk products. Technology, chemistry and
microbiology. London, Chapman & Hall,.
Hui, Y. H. (1993). Dairy Science and Technology Handbook:Product Manufacturing.
Cambridge, VCH Publishers.
K, R. R. (1991). Therapeutic properties of fermented milk. London., Elsevier applied
science.
Pak, T. (1995). Dairy processing handbook. Lund., Tetra Pak Processing Systems AB.
Robinson, R. K. (1994). Modern dairy technology. Advances in milk processing.
London, Chapman& Hall.
Robinson, R. K. (1994). Modern dairy technology. Advances in milk products. London,
Chapman& Hall.
Tamime, A. Y., R. K. Robinson, et al. (1999). Yoghurt Science and Technology.
Cambridge, Woodhead Publishing Ltd and CRC Press LLC.
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