Unit 5 | Principles of Food Science and Nutrition | 5th Semester

Principles of Food Science and Nutrition

Unit V

Unit - V Syllabus

Milk adulteration and its detection, common preservatives of milk, and their detections.Availability, functions, and nutritional deficiency disease of minerals and vitamins.

Notes by Agricorn.in

Milk adulteration and its detection

Milk adulteration is a major problem in the food industry. It involves the addition of substances or alteration of the composition of milk to increase its volume, improve its appearance or texture, or extend its shelf-life. Adulteration of milk not only poses serious health risks to consumers but also undermines the integrity of the dairy industry.

Common forms of milk adulteration include:

1. Water Addition: Water is added to milk to increase its volume, which results in a decrease in milk's nutrient density.
2. Addition of Starch and Sugar: These substances are added to milk to increase its thickness and sweetness, which can mask the dilution of milk with water.
3. Addition of Neutralizers: These are alkaline substances that are added to milk to neutralize the natural acidity of milk, which can result in the formation of curdles or spoilage of milk.
4. Addition of Preservatives: Chemical preservatives like formalin, hydrogen peroxide, and boric acid are added to milk to extend its shelf-life, but can be harmful to human health.
5. Addition of Synthetic Milk: Synthetic milk is produced by mixing vegetable oil, urea, detergent, and other chemicals. It is added to milk to increase its volume and is a serious health hazard.

Methods of detecting milk adulteration include:

1. Chemical Tests: These tests use chemical reagents to identify the presence of specific adulterants in milk. For example, the presence of formalin can be detected using a test kit containing sodium bisulfite.
2. Physical Tests: These tests evaluate the physical characteristics of milk such as its density, viscosity, and freezing point. Adulterated milk has a lower density, viscosity, and freezing point than pure milk.
3. Microbiological Tests: These tests evaluate the presence of microorganisms in milk. Adulterated milk has a higher bacterial count than pure milk.
4. DNA Tests: These tests use DNA analysis to detect the presence of adulterants such as buffalo or goat milk in cow's milk.

To prevent milk adulteration, strict regulations and monitoring of the dairy industry are necessary. Consumers should also be aware of the signs of adulteration and purchase milk from reputable sources.

Common preservatives of milk

There are several types of preservatives that can be used in milk to prevent spoilage and extend shelf life. Here are some of the commonly used preservatives in milk:

Chemical preservatives: Chemical preservatives are substances added to milk to prevent or slow down the growth of bacteria and other microorganisms that can spoil the milk. Examples of chemical preservatives used in milk include sodium benzoate, potassium sorbate, and calcium propionate.

Physical preservatives: Physical preservatives are techniques used to preserve milk without adding any chemicals. Some physical preservatives used in milk include ultraviolet radiation, pasteurization, and homogenization.

Natural preservatives: Natural preservatives are substances that are derived from natural sources such as plants, animals, and minerals. Some examples of natural preservatives used in milk include citric acid, vinegar, and essential oils.

It is important to note that the use of preservatives in milk is regulated by food safety agencies in different countries, and the maximum allowable limit of each preservative may vary. Also, some preservatives may have potential health risks and their use in food products is a subject of ongoing research and debate.

There are several common preservatives used in milk to increase its shelf life and prevent spoilage. Some of these preservatives include:

1. Sodium benzoate: This is a commonly used preservative that prevents the growth of bacteria, yeast, and mold. It is effective at low pH levels, making it suitable for use in acidic foods like milk.
2. Sodium nitrate: This preservative is used to prevent the growth of harmful bacteria and extend the shelf life of milk. It is also used in meat products to prevent the growth of Clostridium botulinum, which can cause botulism.
3. Potassium sorbate: This preservative is commonly used in dairy products like cheese and yoghurt to prevent the growth of mold and yeast. It is also effective against certain types of bacteria.
4. Natamycin: This is a natural antifungal agent that is used to prevent the growth of mold in dairy products. It is commonly used in cheese and other dairy products to extend their shelf life.
5. Hydrogen peroxide: This is a strong oxidizing agent that is used to sterilize milk and other dairy products. It is effective against a wide range of microorganisms, including bacteria, viruses, and fungi.

It is important to note that the use of preservatives in milk is regulated by food safety authorities, and their use is strictly monitored to ensure that they are safe for consumption and do not exceed permissible levels. Additionally, milk manufacturers are required to label their products with the preservatives used, so consumers can make informed choices about the products they purchase.

Their detection

The detection of common preservatives in milk can be done using various methods, including:

1. Chemical analysis: Chemical methods involve the use of chemical reagents to detect the presence of preservatives in milk. For example, the presence of sodium benzoate can be detected by adding concentrated hydrochloric acid and a few drops of ferric chloride solution to milk. The appearance of a violet color indicates the presence of sodium benzoate. Chemical analysis involves for the presence of specific chemicals that are commonly used as preservatives, such as hydrogen peroxide, formaldehyde, or hydrogen peroxide.
2. Chromatographic methods: Chromatography is a technique used to separate different compounds in a mixture. High-performance liquid chromatography (HPLC) and gas chromatography (GC) are commonly used to detect preservatives in milk.
3. Spectroscopic methods: Spectroscopic methods involve using instruments that measure the interaction of electromagnetic radiation with matter to detect the presence of preservatives. Examples of spectroscopic methods used for milk analysis include infrared spectroscopy (IR) and UV-Visible spectroscopy.
4. Enzymatic methods: Enzymatic methods involve using specific enzymes to detect the presence of preservatives in milk. For example, the presence of hydrogen peroxide can be detected using the enzyme catalase.
5. Immunological methods: Immunological methods involve using specific antibodies to detect the presence of preservatives in milk. Examples of immunological methods include enzyme-linked immunosorbent assay (ELISA) and lateral flow assays.

In addition to these methods, there are also rapid testing kits available that can be used to detect the presence of preservatives in milk. These kits are designed to provide a quick and simple way to detect preservatives and are often used in field testing or on-site testing.

Notes by Agricorn.in

Availability, functions, and nutritional deficiency disease of minerals and vitamins

Sure, here is a detailed answer covering the availability, functions, and nutritional deficiency diseases of minerals and vitamins:

Minerals:

1. Calcium: Calcium is an essential mineral for the development and maintenance of healthy bones and teeth. It also plays a role in muscle contraction, nerve function, and blood clotting. Milk is an excellent source of calcium, with one cup providing about 30% of the daily recommended intake. Deficiency of calcium can lead to weak bones, osteoporosis, and an increased risk of fractures.
2. Phosphorus: Phosphorus is important for bone and teeth formation, energy metabolism, and cell function. Milk is a good source of phosphorus, with one cup providing about 20% of the daily recommended intake. Deficiency of phosphorus can lead to weakness, loss of appetite, and bone pain.
3. Magnesium: Magnesium is required for muscle and nerve function, energy metabolism, and bone health. Milk is a good source of magnesium, with one cup providing about 6% of the daily recommended intake. Deficiency of magnesium can lead to muscle weakness, fatigue, and abnormal heart rhythms.
4. Sodium: Sodium is necessary for fluid balance, muscle and nerve function, and blood pressure regulation. Milk contains a moderate amount of sodium. However, excessive sodium intake can lead to high blood pressure and an increased risk of heart disease.

Vitamins:

1. Vitamin A: Vitamin A is important for vision, immune function, and skin health. Milk is a good source of vitamin A, with one cup providing about 10% of the daily recommended intake. Deficiency of vitamin A can lead to night blindness, dry skin, and an increased risk of infections.
2. Vitamin D: Vitamin D is necessary for the absorption and utilization of calcium and phosphorus, and for bone health. Milk is fortified with vitamin D, with one cup providing about 25% of the daily recommended intake. Deficiency of vitamin D can lead to weak bones, rickets in children, and an increased risk of fractures in adults.
3. Vitamin B2 (Riboflavin): Vitamin B2 is necessary for energy metabolism and for maintaining healthy skin and eyes. Milk is a good source of vitamin B2, with one cup providing about 25% of the daily recommended intake. Deficiency of vitamin B2 can lead to cracked lips, sore throat, and skin disorders.
4. Vitamin B12: Vitamin B12 is necessary for the formation of red blood cells and for maintaining healthy nerve function. Milk is a good source of vitamin B12, with one cup providing about 18% of the daily recommended intake. Deficiency of vitamin B12 can lead to anemia, nerve damage, and cognitive decline.
5. Vitamin C: Vitamin C is important for immune function and for the production of collagen, which is necessary for healthy skin, bones, and cartilage. Milk contains a small amount of vitamin C. However, it is not a significant source of this vitamin. Deficiency of vitamin C can lead to scurvy, a condition characterized by bleeding gums, skin rash, and fatigue.

In conclusion, milk is an excellent source of calcium, vitamin A, vitamin D, and vitamin B2, and a good source of phosphorus, magnesium, and vitamin B12. Regular consumption of milk can help prevent nutritional deficiency diseases related to these minerals and vitamins.

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