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Types of Enazymes in milk

1. Endogenous and 2. Exogenous.

Three sources of enzyme in milk:

1. The blood via defective mammary cells.

2. Secretory cell cytoplasm. Some of which are occasionally entrapped with fat globules by the encircling MFGM.

3. The outer layer of MFGM is probably the principal source of endogenous enzymes in milk. The outer layer of MFGM is derived from the apical membrane of the secretory cell which in turn originates from the Golgi membrane and acts as the principal source of enzyme in milk.

General Characteristics of Milk Enzymes

1. Deteriorative character e.g. lipase (commercially most important enzyme in milk), proteinase, acid phosphatase, xanthine oxidase.

2. Preservative enzymes. e.g. superoxide dismutase, sulfhydryl oxidase.

3. As an indicator of the thermal treatment history of milk. Related enzymes are alkaline phosphatase, ϒ glutamyl transpeptidase, and lactoperoxidase.

4. Mastitis infection indicator. Related enzymes are catalase, n-Acetyl-β D-glucosaminidase, and acid phosphatase.

5. Antimicrobial activity.

6. Commercial source of ribonuclease and lactoperoxidase

Common Milk Enzymes and their Role in Dairy Industry

Chemistry of Creaming

After being drawn from animals, normal milk will form a cream layer on standing. Because of the difference in density between fat globules (920 kg m−3 at room temperature) and milk plasma (density 1030 kg m−3), the granules tend to rise. This causes creaming, which we often want to prevent and it enables milk to be separated into cream and skim milk. Creaming is much enhanced when the globules have been aggregated into flocculates, clusters, or granules.

Cream Ripening

This unit operation serves as an intensive preparation of the cream for the churning process. It is divided into two categories.

1. Physical ripening;

2. biochemical ripening The following criteria are influenced by the cream ripening:

• Consistency, firmness, and spreadability of butter.

• Basic water content of butter during the manufacturing process (bound water in butter, which cannot be removed by any mechanical treatment).

• Buttermilk fat content, which has to be minimized.

The melting and solidification behavior of fat depends on the attached fatty acid, which indicate the hardness of the butterfat.

Natural hardness is caused mainly by seasonal feeding of the milk animals. Winter feed with a great deal of dry feed or roughage yields a hard butterfat with a high percentage of saturated and short-chain fatty acids and few double bonds in the fat molecules.

Summer feeding (green grass) results in fat with longer chains and a higher percentage of unsaturated fatty acids with many double bonds. We therefore distinguish between summer fat and winter fat or summer cream and winter cream.

Procedure: weigh vegetables 20 g (for each variation) Water: add sufficiently
1. Cook the vegetable in water in a pan according to the “cooking time” variations given in the table 1 and note down the color, texture and flavor changes takes place during cooking for each variation and record the observations

Objective Methods: Objective Methods are used for evaluation of food quality. These are based on recognized standard scientific tests to any sample of the product without regard to its previous history. They represent the modern idea in quality control (QC) because the human element has been excluded. This method divided into three groups like physical, chemical and microbiological. The devices are used in this evaluation.

Obligate anaerobes: These microbes do no grow in the presence of oxygen.

Obligate parasite: Obligate parasites is host specific and grows on living host only and attach limited range of host and are very difficult or impossible to grow on artificial culture/media.

Obligate thermophile: These microorganisms grow at a temperature between 38-80^oC.

Oenology: Treatments used to prevent spoilage of wine is called oenology. It is synonym to that of enology.

World Scenario

The world climatic conditions are divided into Tropical; Sub-Tropical and Temperate climates. Fruits and Vegetables suited to these climatic conditions are grown successfully. Considering the nutritional and economic importance of fruits and vegetables, there is tremendous increase in area and production of fruits and vegetables throughout the world. The present global scenario of fruit and vegetable crops (areas harvested, production and productivity (yield) has been given in Table 1. It shows that the fruits 865.88 million tones has been harvested from 65.24 million Ha land with productivity 13.27 t/ha (Table 1) where as vegetables produced 1075.20 million tonnes from area 57.00 million ha with yield 18.86 tonnes/ha (Table 1) during 2016.

Concentrated milk products are obtained through partial removal of water which increases the dry matter content of milk. The increase in dry matter content in concentrated milk is proportional to the degree of concentration. The milk concentrate may be prepared from either full-cream whole milk or fat-free skim milk.

Depending on the nature of raw material and other non-milk additives concentrated milks are classified into four broad categories.

1. Sweetened condensed milk

2. Evaporated milk or unsweetened condensed milk

3. Sterile milk concentrate

4. Reconstituted concentrated milk

Sweetened Condensed Milk

One of the earliest dairy products to be produced industrially is sweetened condensed milk. According to FSSA (2006), sweetened condensed milk is the product obtained by partial removal of water from the milk of cow/buffalo with the addition of sugar or a combination of sucrose with other sugars or by any other process that leads to a product of the same composition and characteristics. The fat and/or protein content of the milk may be adjusted by the addition and/or withdrawal of milk constituents in such a way as not to alter the whey protein to casein ratio of the milk being adjusted. It shall have a pleasant taste and flavor and be free from off-flavor and rancidity. It shall be free from any substance foreign to milk. It may contain food additives. It shall conform to the microbiological requirement as laid down by FSSA. The said product shall also conform to the following requirements

Commercially, one of the most significant milk products is ice cream. It is a frozen product which is usually made from milk or cream that has been f lavored with fruits like peaches or strawberries, and spices like vanilla or cocoa, or with sugar or a substitute. Stabilizers are sometimes combined with food coloring. Ice cream mix typically contains 10.0% milk fat, 11.0% solids not-fat, 14.0% added sugar, and 0.3% additives like an emulsifier, stabilizer, f lavor, and color substances.

Standard of Ice Cream

According to FSSA (2006), ice cream, kulfi, chocolate ice cream or softy ice cream means the product obtained by freezing pasteurized milk prepared from milk and/or other products derived from milk with the addition of sweetening agents and fruit products, egg products, coffee, cocoa, ginger, and nuts. It may also contain chocolate, and bakery products such as cake or cookies as a separate layer and/or coating. It may be frozen hard or frozen to a soft consistency. It shall be free from artificial sweeteners. It shall have a pleasant taste and smell free from flavor and rancidity. It may contain food additives. It shall conform to the microbiological requirements as given in FSSA (2006).

Percent Solutions

There are three types of percent solutions. All are parts of solute per 100 total parts of solution. Based on the following definitions you may calculate the concentration of a solution or calculate how to make up a specific concentration

    1.    % W/W - Percent of weight of solute in the total weight of the solution. Percent here is the number of grams of solute in 100 grams of solution. 
        Example: 
        A 100% (W/W) NaCl solution is made by weighing 100 g NaCl and dissolving in 100 g of solution

    2.    % W/V - Percent of weight of solution in the total volume of solution. Percent here is the number of grams of solute in 100 ml of solution. This is probably the least significant way of naming a solution, but the most common way of doing it. In fact, any percent solution not stipulated as W/W, W/V, or V/V is assumed to be % W/V. 
        Example : A 4% (W/V) NaCl solution is 4 g of NaCl in 100 ml of solution.

    3.    % V/V - Percent of volume of solute in the total volume of solution %V/V. Percent here is the number of milliliters of solute in 100 ml of solution. 
        Example: A 10% (V/V) ethanol solution is 10 ml of ethanol in 100 ml of solution; unless otherwise stated, water is the solvent. 

Procedure: Measurement of smoke point of given oils: Heat the given oils in a deep frying pan till fumes come out from oil. Record the temperature when the fumes come out and noted it as a ‘smoke point’. Cool the oil by keeping oil pan at room temperature. After cooling repeat the heating of same oils 2nd and 3rd time to measure the smoke point and record the observations

Food adulteration is a global issue, and because there are insufficient regulations and oversight, developing nations are more vulnerable to it. But in many nations, food adulteration has gone unnoticed. Contrary to popular assumption, milk adulterants can, regrettably, present major health risks that result in fatal diseases. Modern milk adulteration involves increasingly complex techniques, necessitating state- of- the- art research to identify the adulterants. Because milk contains so many nutrients that are needed by both adults and infants, it is referred to as the ideal food. In terms of protein, fat, carbohydrates, vitamins, and minerals, it is among the best sources. Regretfully, milk adulteration is a very common problem worldwide. Potential causes could be the gap between supply and demand, the perishable nature of milk, the low purchasing power of the consumer, and the absence of appropriate detection tests. Because there is insufficient oversight and inadequate law enforcement, the situation is substantially worse in developing and underdeveloped nations. While quantitative detections of adulterants in milk are varied and complex, qualitative detections can be carried out simply using chemical reactions. The type of quantitative detection methods used depends on the milk’s adulterants.

Typical Adulterants in Milk

The addition of vegetable protein, milk from different species, whey addition, and watering are the main adulterants in milk that are known to be economically motivated. There is no serious health risk associated with these adulterations. Some adulterants, though, are too dangerous to ignore. Urea, formalin, detergents, ammonium sulfate, boric acid, caustic soda, benzoic acid, salicylic acid, hydrogen peroxide, sugars, and melamine are a few of the main adulterants in milk that have been shown to have serious negative health effects.

Vacreation: The pasteurization of the milk or cream under reduced pressure by direct steam is called vacreation.

Vacuum: The state of negative pressure. It is equal to atmospheric pressure minus absolute pressure.

Vacuum cooling: A technique of cooling vegetable (leafy vegetables, asparagus, brussels sprouts) having a high surface to volume ratio; rapidly and uniformly by boiling off some of their water at 1⁰C and at low pressure (5 mm of Hg) into a sealed container. The produce is cooled by evaporation of water from the tissue surface and is more rapid than hydro cooling.

Wafer: A thin crisp cake, candy, cracker or chips is known as wafer.

Waffle: A crisp cake of batter baked in a waffle iron is called waffle

Warner-Bartzler Shear: It is one of the oldest but commonly used devices used to measure the tenderness of meat. It is used to test the quality in the cooked meat

Introduction

Whey is the serum or watery part of the milk that remains after separation of curd that result from the acid or proteolytic enzyme mediated co-agulation of milk. It is major by product of dairy industries manufacturing products like channa, paneer, cheese and chakka (Sharma and Bhatia, 1999).The current world production of whey is estimated at about 165 million tones, in that cheese whey accounts for nearly 95 % of total whey. In India near about one million tonne of whey is annually derived, in that major source of whey is from the production of channa, paneer and shrikhand production. This is mostly thrown away as a waste which creates environmental pollution, also in that way about 70, 000 tonnes of Nutritious solids are lost (Puranik, 1999).

    1.    The heifer is bred (naturally or by insemination) before the age of two years.

    2.    The gestation period is nine months and one week.

    3.    After calving, the cow gives milk for 10 months.

    4.    1 – 2 months after calving the cow will again be bred.

    5.    The cow then continues to give milk for about 300 days. This period is known as lactation.

    6.    Milk should preferably be handled in a closed system, to minimise the risk of contamination. It must be cooled to 4 °C as soon as it is produced.

    7.    The content of protein, lactose and ash is somewhat higher in buffalo milk than in cow milk. Buffalo milk contains vitamin A, but lacks b-carotene, which is present in cow’s milk.

    8.    When milk and cream turn to butter, there is a phase inversion from an oil-in-water emulsion to a water-in-oil emulsion.

    9.    In milk, the whey proteins are in colloidal solution and the casein in colloidal suspension.

Fermentation

The decomposition of carbohydrates by microorganisms and enzymes is known as fermentation. During fermentation process of food organic acids and alcohol etc are produced which act as preservatives and also provide fine flavor and aroma that increase the value of raw materials. Most fermented foods contain a complex mixture of carbohydrates, proteins and fats etc. Fermentation occurs when microorganisms consume susceptible organic substances as a part of their own metabolic processes. Natural fermentation is probably oldest form of food preservation.

Post-mortem glycolysis (anaerobic glycolysis)
• Post-mortem glycolysis is the basic function of muscle
• Irreversible anaerobic glycolysis starts after the animal has died and oxygen supply to the muscles is cut
• The various biochemical steps that occur in living animals for the conversion of glycogen into lactic acid when the oxygen supply is insufficient, are basically similar in slaughtered animal also
• After slaughter, during anaerobic glycolysis in normal animals (not in the animals that are exhausted, excited or excessively exercised just prior to slaughter), the glycogen reserve of the muscle decreases appreciably resulting in the lactic acid production which will proceed to a pH level at which the enzymes involved in glycolysis become inactivated
• In classic mammalian muscles this pH will be near to 5.4–5.5 (called Ultimate pH)
• Muscle having almost 600 mg glycogen/100 g muscle at the time of slaughter will reach this pH
• A protein called glycogenin is responsible for starting the glycogenesis (glycogen synthesis) in muscle and it binds with eight glucose molecules to produce a glycosyl-protein (Fig. 12.1)
• Glycosyl-protein is used as primer by the enzyme proglycogen synthase and thus, proglycogen is formed
• This proglycogen is converted into bigger macromolecule by the macroglycogen synthase and its branching enzyme

Abstract

The production of natural food colours through bio-processing is preferred now-a-days due to health related issues associated with their synthetic counterparts. Microorganisms are generally preferred sources as these have high production rate, high growth rate, ease of handling under controlled conditions and absence of seasonal variations. Biopigments can be produced from different genera of bacteria, yeast and mold. Different types and colours of pigments have been produced from microorganisms depending upon their origin, media components and process conditions. The biopigments have variety of applications in food industry such as food additives, food preservatives, biological control agents and nutritional supplements. These have also been associated with therapeutic, and antioxidant properties. Lycopene from B. trispora is used as a food ingredient in dietary supplement. Astaxanthin from X. dendrortious has also been reported to have beneficial effect on human health as it possesses strong antioxidant properties. Arpink red P. oxalicum is used as red colorant in meat products, non-alcoholic drinks, milk products and confectionary. 0- carotene is considered as leading food colorant in world and is applied to range of baked, dairy and canned foods to improve their appearance. The antioxidant andprecursory properties of0-carotene increase its applications in pet foods. Zeaxanthin is used as additives in poultry fed to intensify the colour of the egg yolk. Monascus pigments are utilized for coloration of sausages, ham, marine products and tomato ketchup. Monascus extract is also marketed as dietetic supplement in Japan. Thus, the biopigments can serve as a chromophore for colorant production with broad spectrum of colours and wide applications.

Selection fresh fruits/frozen stored fruits/chilled fruits/fruit pulp/sulphited fruit. Wash them to remove the dairt, dust, stems, leaves, stalks, undesirable portions.

Abstract

Health benefits of aloe vera include its application in wound healing, treating burns, protection against skin damage, lung cancer, intestinal problems, increasing high density lipoprotein (HDL), reducing low density lipoprotein (LDL), reducing blood sugar in diabetics, fighting acquired immune deficiency syndrome (AIDS), allergies and improving immune system. Phytochemistry of aloe vera gel has revealed the presence of more than 200 bioactive compounds. Aloe vera gel is extracted from its leaves and appropriate processing techniques are needed for stabilization and preparation of the food products. Aloe vera gel products have become available in our country for internal consumption as a tonic and diversification in its products is on progress. The use of aloe vera has gained popularity because of herbal movement initiated by naturopaths, yog gurus, alternative medicine promoters and holistic healers. A recent market analysis report indicates that Americans have spent almost 40 billion dollars on functional foods, drinks and supplements for the improvement of their appearance as well as to provide energy and added nutrition to handle health issues such as hypercholesterolemia and diabetes.

Physicochemical parameters of meat
1. Moisture, ash and fat content
• Meat samples are dried at 105 °C for 24 h for determining the moisture content and for ash content analysis, samples are burned at 525 °C
• Fat determination is done by acidic hydrolysis of the sample
• Sample is boiled initially and then cooled and later, it is filtered, washed and dried
• Thereafter, petroleum ether is used to extract the fat
• Ether is evaporated and the remnant is dried and weighed
2. Protein content
• Often, protein in meat sample is estimated using Kjeldahl method
• The protein content is determined by multiplying the nitrogen content in the meat sample by an appropriate conversion factor
• Strong acid is used to digest the meat sample and the released nitrogen is measured by proper titration technique
• Then, the protein quantity of the sample is determined from the nitrogen concentration of the meat
• Kjeldahl method does not determine the protein content in straightway manner; a conversion factor (F) is required to convert the nitrogen content to protein content
• Usually, a conversion factor of 6.25 (corresponding to 0.16 g nitrogen/g of protein) is used for several food samples