PRESENTED BY:

SAQIB RASHID LONE

14PFT011

Introduction:-

There are many different forms of processing to which food may be subjected before we eat it.

All of these processes have some effect on the nutrient con tent.

For example, during the freezing of peas there is about a 10 per cent loss of vitamin C.

Cont…

Nearly every food preparation process reduces the amount of nutrients in food. In particular, processes that expose foods to high levels of heat, light, and/or oxygen cause the greatest nutrient loss.

Nutrients can also be washed out of foods by fluids that are introduced during a cooking process.

Vitamin c is the most thermolabile vitamin and is also easily leached into cooking water or canning syrup.

Typical Maximum Nutrient Losses (as compared to raw food)

Vitamins Freeze Dry Cook Cook+Drain Reheat

Vitamin A 5% 50% 25% 35% 10%

  Beta Carotene 5% 50% 25% 35% 10%

  Lycopene 5% 50% 25% 35% 10%

Vitamin C 30% 80% 50% 75% 50%

Thiamin 5% 30% 55% 70% 40%

Riboflavin 0% 10% 25% 45% 5%

Niacin 0% 10% 40% 55% 5%

Vitamin B6 0% 10% 50% 65% 45%

  Folic Acid 5% 50% 70% 75% 30%

Vitamin B12 0% 0% 45% 50% 45%

Minerals Freeze Dry Cook Cook+Drain Reheat

Calcium 5% 0% 20% 25% 0%

Iron 0% 0% 35% 40% 0%

Magnesium 0% 0% 25% 40% 0%

Phosphorus 0% 0% 25% 35% 0%

Potassium 10% 0% 30% 70% 0%

Sodium 0% 0% 25% 55% 0%

Zinc 0% 0% 25% 25% 0%

Copper 10% 0% 40% 45% 0%

Nutrients may be lost during cooking in two ways :1. By degradation ,which can occur by

destruction or by other chemical changes such as oxidation.

2. By leaching into the cooking medium

Vitamins are susceptible to both processes while minerals are affected only by leaching.

Loss of vitamin C in relation totime and temperature during steaming of red cabbage:-

Consuming Raw Foods

The amount of nutrient loss caused by cooking has health-conscious consumers to eat more raw foods.

However cooking is also beneficial, because it kills potentially harmful microorganisms that are present in food supply.

Effects of Freezing on nutrients:- freezing can be a very good way to

preserve the nutritional value, texture and flavor of many foods, many of the vitamins and minerals will keep fairly well in frozen foods.

Research showing that anthocyanin flavonoids can be well preserved during freezing. Even though they are rather delicate, a recent study found no significant reduction in the levels of anthocyanins in blueberries after three months of freezing.

Cont…

About 25% of the vitamin C and a greater percentage of folate are lost during the blanching process that occurs before foods are frozen. About 10% of thiamin (vitamin B1) is also lost during blanching.

Effects of drying on nutrients:- Drying using four different methods

viz., osmo-air drying, direct sun drying, indirect solar drying and oven drying. The osmo-air drying method was found to be the best method for drying of aonla because of better retention of nutrients like ascorbic acid and sugars.

The level of antinutrients like tannins was also found to be lower in osmo-air dried aonla

Cont…

compared to other methods of drying because of leaching. Browning of the dehydrated fruits was also minimal in the case of osmo-air dried fruits. The nutrient content in osmo-air dried aonla was satisfactory after 90 days of storage.

Effects of heat processing on nutrients:- Heat processing is one of the most

important methods for extending the storage life of food stuffs , however heat processing also has a detrimental effect on nutrients since thermal degradation of nutrients can and does occur

Therefore thermal processing makes it possible to extend and increase availiability of foodstuff to the consumer but the foodstuff may have a lower nutrient content compare

Cont….

To the fresh food stuff. The challenge to the food processing

industry is to minimize the loss of nutrients during thermal processing while providing an adequate process to ensure an extended shelf life.

Effect of microwaves on nutrients:- Microwave cooking has gained

considerable importance as an energy-saving, convenient, and time-saving cooking method. Most reports indicated that microwave cooking resulted in higher moisture losses compared with conventional methods.

Overall, the nutritional effects of microwaves on protein, lipid, and minerals appear minimal.

Cont…

There is no report on the effects of microwaves on carbohydrate fraction in foods. A large amount of data is available on the effects of microwaves on vitamins.

In conclusion, no significant nutritional differences exist between foods prepared by conventional and microwave methods.

Nutrition additives

Any natural or synthetic substances, such as salt, monosodium glutamate, or citric acid, used in the commercial processing of food as preservatives, antioxidants, emulsifiers, etc, in order to preserve or add flavour, colour, or texture to processed food…

REMEMBER…

The more heavily processed foods are the less nutritious they become…