Food fats and oils

Food fats should contain polynonsaturated fat acids, fat-soluble vitamins in the structure (retinol, kaltsiferoly and tokoferoly), lecithin and fitosteriny, a cholesterol small amount. Besides, they should be acquired well.

The butter, pork and beef fat, margarine, vegetable oils concern food fats and t, d. Any of them does not possess the qualities set forth above to the full. So, the butter contains retinol and kaltsiferoly, but has no tokoferolov and polynonsaturated fat acids. Vegetable oils (sunflower, cotton) are rich with polynonsaturated fat acids, contain tokoferoly, fosfatidy, but have no retinola and kaltsiferolov. Therefore at a diet there should be both animal, and vegetative fats.

The Butter, on the structure being thin emulsiej, is easy emulgiruetsja in the food channel and is well acquired, that does by its irreplaceable product in a food of children, the weakened people and old men. The dishes prepared on this fat, possess pleasant taste and a smell. Nonsaturated fat acids absent in a butter are easily supplemented with other fats rich with these acids (vegetable oil). Power value 100 g a butter makes 3130 kdzh (748 kcal). Wrong storage of animal fats can lead to deterioration organolepticheskih properties and first of all to occurrence of metal or wood smack.

At long storage of a butter and other animal fats they get greenish colouring. pozelenenie fat begins usually with a surface, but then gets into thickness.

Now from vegetable oils for the food purposes are used sunflower, cotton, soya, corn, olive. Power value of oils the big: in 100 g oils nearby 3766 kdzh (900 kcal). In sunflower-seed oil more than polynonsaturated fat acids (65%), in soya - tokoferolov and fosfatidov, in corn - fitosterinov (580 mg). A lack of vegetable oils is their ability quickly to be oxidised and spoil. Thus in them disintegration products collect: carbonic acid, acetic and ant acids. Vegetable oils at oxidation get denser, and in the subsequent get unpleasant burning taste and a pungent smell that speaks progorkaniem and osalivaniem oils. On a way of processing distinguish the refined and crude not refined oils.

The Increase in acidity of fats speaks gidrolizoj them for the account fermentativnoj activity of microorganisms, got to fats. High humidity and air temperature in a premise in which fats are stored promote this process. Kislotonakoplenie and oxidation of fats are initial signs of damage which do not change essentially organolepticheskie property. Further these properties sharply worsen at progorkanii and osalivanii fats. progorkanie fat occurs at the expense of oxidation by its oxygen of air. Aldehydes and ketony, providing to it unpleasant taste and a pungent smell are thus formed. As a rule, progorkanie taste and a stearin smell is accompanied osalivaniem therefore fats get a white shade.

Thus, in the oxidised and decayed fat there are the changes reducing its biological value at the expense of reduction of quantity of polynonsaturated fat acids and vitamins. Besides, products of decomposition of fat possess toxic action. Therefore „prorancid and osalivshiesja fats are unsuitable for the food purposes.

At sanitary inspection realisation behind conditions of storage and quality of fat, accordingly STATE THAT on a certain kind of fat, carry out laboratory research organolepticheskih and its physical and chemical features. At organolepticheskom research extraneous smells, change of taste, colour and a fat consistence are not supposed. At physical and chemical research indicators of freshness and quality of food fats are defined depending on the nature of fat and degree of its clearing. For example, the quantity of a sediment in not refined sunflower-seed oil should be no more than 0,2%, and in not refined cotton - 0,3%. The refined oils of a sediment should not have absolutely. At a volume method of definition the sediment should not exceed 3%.

The Important indicator of freshness of fats is the maintenance of free fat acids. In vegetable oils it express acid number, and in a butter - acidity degree. The acid number is a quantity of milligrammes caustic kalija, necessary for neutralisation of free fat acids in 1 g fat. Acidity of a butter express in degrees Kettstorfera - quantity of milliliters 0,1 n. The alkali solution, necessary for neutralisation 5 g the oils, increased on 2. Acidity of a butter should not exceed 3 hailstones, the acid number of the sunflower refined oil should be no more than 0,4, cotton-ADZ, not refined oils-6,7.

The Indicator of freshness of fats is also reaction on progorkanie. It characterises deeply come processes of splitting and oxidation of fats and is based that at progorkanii fats from polynonsaturated fat acids aldehydes are formed: epigidrinaldegid, glitsid th aldehyde. In prorancid fat they are in the connected condition and are released by means of hydrochloric acid. Addition to the released aldehydes or rezortsina gives florgljutsi th pink or red colouring. At positive reaction on progorkanie and unsatisfactory organolepticheskih indicators the product is rejected. According to GOST 5.1030 - 71 ' Oil creamy. Requirements to quality of certified production ', the fat maintenance in a salty butter should make 81%, in unsalted - 83, in creamy margarine - 82%. At the smaller maintenance of fat food value of a product decreases.

The Great value has also moisture content in food fat which is defined by fat heating at 105 “With to poburenija. Moisture content in a butter should not exceed 16%, in vegetable oils - 0,15% (in refined) and 0,3% (in not refined).

Except listed above the indicators characterising the nature and a kind of fat, define also iodic number, fusion temperature, factor of the refraction which sizes should be compared with normalised in corresponding gostah.