Laboratory researches

Laboratory research of canned food carry out according to operating gostam. For this purpose select not less than 10 units of packing.

Before research carrying out define presence of defective cans - bombazhnyh, punched, podtechnyh, with broken poludoj (the tin becomes covered by a thin layer of tin), deformed, ' hlopushej ' (false bombazhem), rusty.

Then study a condition of an internal surface banok. On it there can be the dark stains caused by corrosion - razedaniem poludy pouring and an iron exposure. It can be found out mramornost, i.e. Alternating dark brown strips and the stains caused by sulphurous connections iron and tin which are allocated at avtoklavirovanii products. Shine presence on an internal surface banok is a good sign.

Dimness can be transferred and to a product (corn, a green peas). Considering it, such products pawn in the banks which internal surface is covered by a varnish and vystelena parchment. It is necessary because at dissolution poludy in a tinned product can pass salts of heavy metals. Therefore such canned food investigate on the lead and tin maintenance. The quantity of tin in canned food is supposed no more than 200 mg on 1 kg of a product, and lead should not be in general.

Presence mramornosti is not a poor quality sign, and such canned food are realised without restriction under condition of positive results organolepticheskogo researches.

The Organoleptichesky estimation of canned food is made at contents research banok. Thus define following defects: presence of a putrefactive smell of contents of canned food, crystals (the condensed milk); colour change (chernilno-violet colour of fruit canned food). If the smell very strong, a product is rejected.

In canned food define also quantity of salt, solids, connections of copper and acidity. The maintenance of chloride of sodium in canned food should make 1,5-3%, in preservah - 9-13%. The maintenance of connections of copper in canned food with tomato pouring is supposed no more than 8 mg on 1 kg of a product.

Concentrates represent the dehydrated, concentrated, pressed foodstuff and the half-finished products convenient for storage and fast preparation. Manufacture of food concentrates consists of clearing and thermal processing of raw materials (groats, dried vegetables, fat, seasonings, starch, sugar), dosages of components, their mixing, pressing and packing. As an example can serve krupjanye concentrates (buckwheat, ovsjanye, pearl-barley), not demanding cookings; it is enough to fill in such concentrates with boiled water and to sustain some minutes (usually 10-15 mines). At preparation of such concentrates raw materials subject to deep hydrothermal processing in a steam sterilizer, to dehydration at 200-400 В°s and to vigorous hashing. Food concentrates can be stored about one year. In comparison with initial raw materials they have considerably smaller volume and weight. Food concentrates are widely applied on expeditions, campaigns and field conditions.