The chemical composition and taste of food products are determined by the content of nutrients and other compounds (organic acids, tannins, essential oils, enzymes , alcohols, etc.). Chemical composition, nutritional value and biological effect of food products are mixed substances. Some of them are of primary importance as sources of plastic (“growth”) substances (food products of animal origin — meat, fish, milk, etc.); others are mainly energy sources (grain products, sugar , fat); Third provide the necessary biologically active components (vegetables, fruits, vegetable oils, yeast, liver, lactic acid products).
The chemical composition and nutritional value of some of the most common foods, see the table.
The digestibility of food products depends on various factors, including the ratio of animal and vegetable products contained in the diet, methods of culinary processing of food, the age of a person, and the state of the gastrointestinal tract. Vegetable products are absorbed worse than animals, in the first place, this refers to proteins. The protein digestibility of food products of animal origin reaches 96%; 70–85% of protein is absorbed from plant foods, depending on the type of food and the nature of its processing. The digestibility of plant foods is somewhat increased in mixed foods. In the usual mixed diet, the absorption of protein is 84.5%, fat - 94%, carbohydrates - 94-96%.
When determining the nutritional value of food products, it is necessary to take into account the content of the waste - inedible parts of food products (the skin of potatoes, some vegetables, the insides of fish and poultry, bones and fascia of meat, etc.). In some food products, waste constitutes up to 50% of the weight of the product.
Food spoilage is caused by the decomposition of organic substances contained in them (proteins, fats, carbohydrates). The accumulation of decay products causes specific unpleasant changes in the organoleptic properties of food products. Under normal storage conditions, food products are divided into perishable and non- perishable . The first are meat, fish, milk, egg melange, many berries, edible greens, etc., which are quickly deteriorated by microorganisms. Non-perishable food products (grain, flour, cereals, pasta, etc.) contain, as a rule, little water. In order to lengthen the shelf life of food products, they are subjected to a special treatment - canning (see Canned food).
In the implementation of current sanitary supervision of food storage conditions, it is necessary to monitor compliance with the following requirements.
1. Observance of temperature condition at preservation of perishable goods.
2. Compliance with the established shelf life of food products.
3. The inadmissibility of joint storage of finished products with raw foods and the prohibition of storage of spoiled food.
4. Regular disinfection, cleaning and cleaning of chilled chambers, storerooms, cellars and other places of food storage.
In the USSR, food quality is controlled by government agencies. The main legislative documents are the State All-Union Standards (GOST) and technical conditions (MRTU, RTU TU, V TU).
Each standard covers all the most important issues related to product quality, gives physico-chemical and bacteriological indicators, rules for sensory evaluation, packaging, reception systems, research methods, etc. When conducting a sanitary examination, food products can be considered conditionally valid, tons . e. products that after processing can be used for food.
To solve the issue of suitability for nutritional purposes of a non-standard product can only sanitary service. Food quality control is carried out by the State quality inspectorates at ministries and departments, and the sanitary-epidemiological service of the ministries of health monitors compliance with sanitary and hygienic indicators.Go
Food products are divided into animal, plant and synthetic.
By chemical composition, food properties and biological effects, food products are mixed substances. Some of them are of primary importance as sources of plastic and growth substances, others serve mainly as a source of energetic materials, third provide the necessary, vital, biologically active components (see table). The most important component of foods of animal origin is protein (see Proteins), containing all the essential amino acids. The digestibility of animal protein reaches 96%. The digestibility of protein from plant foods is in the range of 70-85%, depending on the food product and the nature of its processing. Use in certain ratios of animal and plant foods allows for optimal protein nutrition by complementing their amino acid composition.
The sources of plastic substances, in addition to protein, can be attributed to food products rich in assimilable calcium (see) and phosphorus (see). In this respect, milk (see) and cheese (see) are unsurpassed, the calcium of which is in the most favorable ratio with phosphorus.
Energy sources in human nutrition are foods rich in carbohydrates (see) and fats (see). The main sources of carbohydrates are the products of grain processing, mainly bread (see Bread, bakery products), cereals (see). The absorption of carbohydrates reaches 94-96%. Due to their provided more than half the energy value of the daily diet. Sugar and sugary foods are also an important source of energy (see Honey, Confectionery, Sucrose, Sugar) and fats.
The third group of food products consists of sources of biologically active components of the poor: vitamins (see), enzymes (see), phosphatides of trace elements (see). These include many vegetables (see), fruits (see), yeast (see), vegetable oils, and animal products include liver, fish oils, especially liver, lactic acid products.
Vegetables, fruits, berries supply the main amount of ascorbic acid, P-active substances and carotene, as well as pantothenic and folic acids, inositol, etc. These vitamins contain especially many pectin substances (12%) and inositol (250 mg%).
High quality food in the USSR is ensured by compliance with the requirements of GOST and temporary technical conditions (VTU), which are mandatory for all organizations producing and supplying food products. The production of non-standard food products, as well as their falsification, is punishable by law.
Food products restricted to the USSR include surrogates, which can be produced instead of natural foods only by special permission, such as barley coffee, fruit tea, etc. Surrogates should not contain any harmful substances.