Milk Products

Introduction

“Milk Product” means a product obtained by processing of milk, which may contain food additives and other
ingredients functionally necessary for the milk product. Milk products form a significant part of human diet. They are rich sources of nutrients such as proteins, fat, vitamins and minerals;ironically, it is because of this that are susceptible to rapid microbial growth. In some instances, this microbial growth may be beneficial(such as in Cheese, dahi), while in others it is undesirable(such as in Cream, khoa ,Ice-cream).It is well established that enhancement of milk production and rise in standard of living, the demand for dairy products increases. Some of the dairy products have exceptionally long shelf life which can easily transfer milk solids from flush season to lean season, from high producing geographical regions to low producing regions and from one country to another country.There are numerous kinds of forms of dairy products available all over the world.

1) Fat-Rich Dairy Products

   a) Malai

Malai is the firm skin that forms on the surface of boiled and cooled milk. It is analogous to British 'clotted cream'.The yield of malai depends on type of milk and the temperature to which it is boiled. To meet the PFA requirements, malai should contain a minimum of 25% milk fat.In India malai collected and set aside over a week is effectively used for preparing ghee in traditional manner.

   b) Cream

Cream means the fluid product comparatively rich in fat, in the form of an emulsion of fat-in- skimmed milk(oil in water), obtained by physical separation from cow milk,buffalo milk or milk of any other species.Simply cream is yellowish component of milk, rich in fat globule. Cream for sale to consumers is produced with different fat contents that are

→Low fat cream                               (10-40%)
→Medium fat cream                      (40-60%)
→High fat cream                             (﹥60%)
→Half cream                                     (≥12%)
→Sterilized half cream                   (≥12%)
→Single cream                                  (≥18%)
→Sterilized(or canned)                   (≥23%)
    cream       
→Whipping cream                            (≥35%)
→Whipped cream                             (≥35%)
→Double cream                                 (≥48%)
→Clotted cream                                (≥55%)
→Plastic cream                                  (≥80%)

   c) Butter

Butter means the fatty product principally in the form of an emulsion of the the type water-in-oil derived exclusively from milk or milk products, or both. The two principal types of butter produced are table butter(minimum moisture 16%, mini. fat 80%, maximum milk solid-not-fat 2.0%, maxi. common salt 3%)and white butter/cooking butter(mini.fat 76%).

d) Ghee

Ghee is one of the oldest and important traditional dairy products of India.Ghee may be defined as the heat clarified butterfat prepared from desi butter, creamery butter or cream from cow, buffalo, goat or sheep milk or their mixtures and having characteristics cooked or acidic flavor and grainy texture.Ghee contain 0.5%  maximum moisture, 99.5% minimum milk fat, 3% maxi. FFA as Oleic acid. Ghee is good source of energy and Vitamin A,D,E and K. 

 

e) Butteroil( Anhydrous Milk Fat)

Butteroil is the fat concentrate obtained exclusively from butter and also cream and resulting from the removal of practically the entire water and solids-not-fat content.According to FSSAI, anhydrous milk fat should have a minimum fat content of 99.8% and water not exceed 0.1%.

 f) Low- Fat Spreads

Butter unfortunately has poor spread-ability over the temperature range (below 15 C), it is normally used. At refrigeration temperature, it is brittle or hard and difficult to spread.Temperature higher than 24 C causes butter to soften drastically and may result in oiliness.Thus for good spread-ability fat  content reduced to 39-41% and known as low fat spread.

2) Fermented Dairy Products

   a) Dahi

Dahi or curd is a semi solid product, obtained from pasteurized or boiled milk by souring, using harmless lactic acid or other bacterial cultures. Dahi may contain additional cane sugar. It should have the same minimum percentage of fat and solids-not-fat as the milk from which it is prepared.
                                                                Chemical Composition of Dahi

   b) Mishti dahi

Misti dahi is also known as Misti doi, Payodhi and Lal dahi. It is a traditional sweetened fermented milk product popular in the eastern part of India, notably West Bengal, Bihar and Assam. It is prepared by lactic acid fermentation of sweetened milk. A good misti dahi has a characteristic brown colour, firm consistency, smooth texture and caramelized flavour. Buffalo milk is preferred for the preparation of Misti dahi due to high fat content, which induce a rich creamy product with excellent mouth feel.It should have Milk Fat 4-5%, Milk SNF 11-13%, Sucrose 17-18%,  Total solids 32-36%.

 c) Chakka 

Chakka can be described as strained dahi, in other words it is the curd mass obtained after removing whey from dahi, either through muslin cloth or basket centrifuge. Chakka is the base material for the production of shrikhand and shrikhand wadi.

                                                                  FSSAI Standard for chakka 

 d) Shrikhand

Shrikhand is a popular fermented, sweetened, indigenous dairy product having semi solid consistency with typical sweetish-sour taste.It is prepared by mixing chakka with sugar, color, flavor, spices and other ingredients like fruit pulp, nuts etc. to form soft homogeneous mass.

    e) Yoghurt

Yogurt is probably the most popular fermented milk. It is made in a variety of compositions (fat and dry-matter content), either plain or with added substances such as fruits, sugar, and gelling agents. The essential flora of yogurt consists of the thermophiles Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus. For a satisfactory flavor to develop, approximately equal numbers of both species should be present.Volatile compounds produced by the yogurt bacteria include small amounts of acetic acid, diacetyl, and most importantly, acetaldehyde.

    f) Lassi

Lassi is a popular refreshing drink generated during the production of butter from dahi by desi method.This product used with or without sugar or salt depending upon the consumer's preference.

    g) Cultured buttermilk

Cultured butter-milk is the fluid remaining after ripened cream or sour cream is churned into butter. It is prepared by souring true butter-milk or more commonly skim milk with a butter starter culture that produces a desirable flavour and aroma.It has  0.8-0.85% lactic acidity and 0.5-3% fat. It is prepared by using mixed culture consisting of  L.lactis, L.lactis subsp. diacetylactis, L.cremoris and Leuconostoc Citrovorum.

    h) Acidophilus milk

Acidophilus milk defined as a highly acidic product produced by fermentation of milk with          Lactobacillus acidophilus. Acidophilus milk is known widely more for its possible therapeutic value than for its flavor. It recommended for controlling several intestinal disorder and proper use of it beneficial in relief from constipation.

    i) Kefir

Kefir is an acidic mildly alcoholic distinctly effervescent product made from milk of goat,sheep or cow by fermentation.It contain about 1% lactic acid and 0.5-1% alcohol.During fermentation of the milk, the grains grow due to coagulation of protein, while they become connected by means of a formed polysaccharide (kefiran).The microflora of kefir is variable. Lactococci (L. lactis sspp. lactis and cremoris, and L. lactis ssp. lactis biovar. diacetylactis), leuconostocs (Leuc. lactis and Leuc. cremoris), and lactobacilli (Lb. brevis, Lb. kefir, sometimes also Lb. delbrueckii ssp. bulgaricus and Lb. acidophilus) can form lactic acid, whereas yeasts, including Candida, Kluyveromyces, and Saccharomyces species, produce alcohol.

    j) Kumiss(Milk Wine)

Kumiss is a well-known milk drink in Russia and western Asia. Formerly, the cultured milk was valued because of its supposed control of tuberculosis and typhus. The product is traditionally made of mares’ milk but is now often made from skimmed or whole cows' milk with added sugar.It contain 0.7-0.8%(Av. 0.7-0.9%) of lactic acid, 1.3% of ethanol and 0.5-0.88% of carbon dioxide.Starter culture contain Lactobacillus/Bacterium orienburgii, Lactobacillus bulgaricus, L.acidophilus and lactose fermenting yeasts namely Torula kumiss and Saccharomyces lactis.

    k) Cheese

Cheese is a product made from the curd obtained from milk by coagulating the casein with the help of rennet or similar enzymes in the presence of lactic acid produced by added or adventitious microorganisms, from which part of the moisture has been removed by cutting,cooking and a pressing, which has been shaped in a mould, and then ripened by holding it for some time at suitable temperatures  and humidity. 

Cheeses can be classified on the basis of their rheology, and according to the manner of ripening as shown below:

1) Very hard (grating) - Moisture < 35% on matured cheese and ripened by bacteria, e.g. Parmesan, Romano.

2) Hard - Moisture < 40%

a) Ripened by bacteria, without eyes: Cheddar

b) Ripened by bacteria, with eyes: Swiss

3) Semi-hard - Moisture 40-47%

a) Ripened principally by bacteria: Brick

b) Ripened by bacteria and surface microorganisms: Limburger

c) Ripened principally by blue mould: i) External –   Camembert 

                                                                           ii) Internal –   Gorgonzola, Blue, Roquefort.

4) Soft - Moisture > 47%

a) Unripened – Cottage

b) Ripened – Neufchatel

3) Heat Desiccated Products

   a) Khoa

Khoa by whatever name it is sold such as Khoa or Mawa or any other region specific popular name means the product obtained by partial removal of water from any variant of milk with or without added milk solids by heating under controlled conditions.It shall confirm to that Std. mini. 55% Total solid,  mini.30% Milk fat on dry matter basis, maxi. 6.0% ash, 0.9% maxi. titrable acidity.Types of  Khoa are 

                                                                           Dhap

                                                                         

                                                                            Pindi

                                                 

                                                                        Danedar

⟹Khoa- based Sweets

• Burfi
• Peda
• Kalakand
• Milk Cake
• Kunda
• Gulabjamun
• Kalajamun
• Pantua

   b) Rabri

Rabri is a sweetened concentrated whole milk product with thickened malai layer obtained by evaporation and concentration of milk. Buffalo milk is preferred for preparation of rabri.

   c) Basundi

Basundi is a heat-desiccated, thickened milk dessert, having white to light caramel colour, creamy consistency with soft textured flakes that are uniformly suspended throughout the product matrix.
Traditionally it is prepared by heating buffalo whole milk in a pan over fire. Milk is thickened through evaporative heating with occasional scraping at the bottom. With progressive boiling, more and more thickening of milk occurs. The milk is concentrated to the consistency of the condensed milk and sugar (about 15-17% of concentrated milk) is added and stirred into the milk until it is fully dissolved.Now removed from fire and flavors are added.It is usually served chilled. 

4) Heat and Acid Coagulated Products

    a) Paneer

Paneer is a heat-acid coagulated milk product obtained by coagulating standardized milk with the permitted acids at specified temperature. The resultant coagulum is filtered and pressed to get the sliceable curd mass.

    b) Chhana    

Chhana is an acid coagulated product obtained from milk. The curd mass obtained when milk is coagulated with the organic acids such as citric acid, lactic acid at higher temperature and after subsequent drainage of whey, mass of curd obtained is called chhana. It is similar to paneer except pressing of curd follow in paneer where in chhana curd mass does not pressed.

⟹Chhana- based Sweets

• Rasogolla
• Sandesh
• Rasomalai
• Rajbhog
• Pantooa
• Chhana podo

5) Concentrated Milks

    a) Sweetened Condensed Milk

Sweetened condensed milk is milk that is concentrated by evaporation, to which sucrose is added to form an almost saturated sugar solution, after which it is canned. The high sugar concentration is primarily responsible for the keeping quality of the product and for its fairly long shelf life, even after the can has been opened, although it then will eventually become moldy.

    b) Evaporated Milk

Evaporated Milk means the product obtained by partial removal of water from milk by heat or any other process which leads to a product of the same composition and characteristics.Evaporated milk is sterilized, concentrated, homogenized milk. The product can be kept without refrigeration and has a long shelf life; it is completely safe for the user. After dilution, flavor and nutritive value of the product are not greatly different from that of fresh milk. A major problem with sterilization is the heat

stability; the higher the concentration of the milk, the lower its stability.That is why concentrating cannot be by more than about 2.6 times, which corresponds to a level of about 22% solids-not-fat in the evaporated milk.

6) Ice-cream and Frozen Dessert

    a) Kulfi

Kulfiis an indigenous frozen milk product. The method of manufacture of kulfi varies widely. The conventional method of kulfi making consists of boiling of milk,addition of sugar, concentration of milk to 2:1 level and addition of khoa,malai, flavour etc. to the concentrated cooled milk. Kulfi mix is then filled into metallic cones and the top of the cone is covered with a lid. The mixture in the moulds is frozen in large earthen vessels containing ice – salt mixturein the ratio of 1:1.

    b) Milk Ice

A product similar to ice cream containing 2 -7% fat and 12-15% MSNF, sweetened, flavoured and frozen like ice cream.

    c) Malai- ka -burf

This term is applied to a variety of frozen product in which sweetened milk or malai may form the chief ingredient.

7) Dairy Byproducts

    a) Skim Milk

When whole  milk is subjected to high centrifugal force then it is separated into cream and skim milk(Skim milk= Milk - Fat).It has lowest amount of fat less than and equal to 0.5%.It is a by product obtained during preparation of cream for either butter and ghee manufacturing.

    b) Buttermilk

Butter milk is similar to skim milk in composition except acidity of the product. It is generated during the production of butter from cream by desi method. To this butter milk salt, coriander, ginger, onion are added to improve palatability. It is high in potassium, vitamin B12, calcium, and riboflavin as well as a good source of phosphorus. It contains higher amounts of phospholipids. According to Ayurveda it reduces bloating of stomach, and helps in curing indigestion.

    c) Whey

• Whey is the fluid milk product obtained during the manufacture of cheese, casein or similar products by separation from the curd after coagulation of milk or of products obtained from milk, or both. Coagulation is obtained through the action of, principally, suitable enzymes of non-animal origin.

• Acid whey is the fluid milk product obtained during the manufacture of cheese, casein, paneer, channa or similar products by separation from the curd after coagulation of milk and of products obtained from milk. Coagulation is obtained, principally, by acidification and heating.

8) Infant Milk Foods

Infant Milk Food means the product prepared by spray drying of the milk of cow or buffalo or a mixture thereof. The milk may be modified by the partial removal/substitution of different milk solids; carbohydrates, such as sucrose, dextrose and dextrins/maltodextrin, maltose and lactose; salts like phosphates and citrates; vitamins A, D, E, B Group, Vitamin C and other vitamins; and minerals like iron, copper, zinc and iodine.
The product shall be free of lumps and shall be uniform in appearance. It shall be free from starch and added antioxidants.
Breast feeding of young babies is undoubtedly preferable to ensure the development of a healthy child. However, breast feeding is not always possible, and then the baby should be offered a surrogate. Unmodified cows’ milk is definitely unsuitable, a reason why specific infant formulas have  been developed. These are for the most part based on fractions of cows’ milk.