The proteins containing everything irreplaceable amino acids are called full. They contain in meat, fish, milk, eggs. The proteins which are not incorporating at least one irreplaceable amino acid treat the defective.
Process of rancidification of fat is followed by profound changes and proceeds under the influence of various factors: oxygen, light, water, enzymes. As a result of rancidification of fat aldehydes, ketones and other substances, harmful to an organism, are formed.
Lactose (dairy sugar) contains in milk, consists of the remains of a galactose and glucose. Under the influence of enzymes of lactic bacteria lactose sbrazhivatsya with formation of lactic acid. Receiving fermented milk products is based on it. At hydrolysis of lactose glucose and a galactose are formed.
In vegetable fats nonlimiting fatty acids prevail, the majority of fats have a liquid consistence. They are well acquired by an organism in a cold state and therefore are widely used in cookery for seasoning of cold appetizers.
Starch contains in phytogenesis products: flour, grain, pasta (70 — 80%), potatoes (12 — 24%), etc. Grains of starch of various plants on a structure and the size are not identical: the largest grains of an oval form at potato starch, the smallest of an angular form — at rice. The external part of grain of starch consists of amylopectin, internal — of amylase. Amylopectin when heating with water bulks up and kleysterizutsya, the increase in volume when cooking grain and pasta results. At storage of products (bread, boiled potatoes, etc.) the retrogradation (aging of kleysterizovanny starch with allocation of droplets of water is observed. In cold water starch is insoluble. Under the influence of amylase enzyme starch is split to dextrins, under the influence of amylase – to a maltose which in turn under the influence of enzyme of a maltose turns into glucose. Conversion receive treacle. At consumption of starchy products starch under the influence of osakharivayushchy enzymes of a saliva and digestive juice osakharivatsya and is well acquired. Digestion of starch happens gradually, in process of its splitting. Characteristic reaction for definition of starch in foodstuff is effect of iodine which paints starch in blue color.
— Bioses have the general formula C12H22O1 These are white crystal substances, well soluble in water, sweet on taste. However sweet of various sugars is not identical (if to accept sweet of sucrose for 100, at an identical temperature sweet of other sugars makes: fructose — 173, glucose — 74, maltoses and galactoses — 32, lactoses — to 1 K them carry sucrose, a maltose, lactose and a tregaloza.
Soluble squirrels when heating to 70 — 80 °C curl up (denature). Thus their ability to connect water decreases, they lose part of moisture. Reduction of weight and volume of meat, fish when cooking and frying is explained by it. The denaturation of proteins can be besides thermal acid, under the influence of salts of heavy metals (a vysalivana and alcohols. Process of a denaturation of proteins is irreversible.
The formed free fatty acids give to broth a turbidity, unpleasant taste and a smell. Hydrolysis of fat happens on a surface of contact of fat and water. The less fat balls forming an emulsion the surface of contact of fat and water is more and the hydrolysis speed is higher. Therefore broths need to be cooked at moderate heating, removing fat from a surface.
The role of proteins in a human body and animals is various. Their molecules of a vysokospetsializirovana in view of the fact that for each protein are characteristic a certain sequence of amino acids and their number. Shift only of one rest of amino acid on other place in an amino-acid chain of a proteinaceous molecule conducts to very considerable change of properties of protein and therefore each protein has the special physiological functions. Divide:
In cookery properties of fats to dissolve the painting and aromatic substances, vitamins are used. The carrots roasted in fat, onions, white korenye, a tomato mashed potatoes give to dishes beautiful color and pleasant aroma.