Профессионально-ориентированное чтение для магистров и аспирантов пищевых специальностей университета (сборник текстов). Михедова Л.Г. - 7 стр.

40% moisture. The dough is forced through an extruder to give        products at the end of the meat chain can be more or less
it a specific shape and is dried to 12-15% moisture. The pellets     complete. It is customary to classify food products into three
are then loaded into guns or popping vessels. These guns are         categories according to their moisture content and water activity.
about 30 in. long and 6 in. in diameter. They are sealed, rotated,   Food products can have high intermediate and low equilibrium
and heated to 425°C. Pressure may build to 200 psi. The trip         moisture contents. Fresh meat belongs to the first category;
valve is opened and the material explodes out. Many variations       dried sausage, cured ham, and dried beef to the second; and lard
are possible, using different flavors, shapes, types of doughs,      to the third. Forms of dried meat prepared in Africa and
etc. Wheat and rice kernels can also be gun-puffed. Milled rice      America usually also belong to the third category. For products
and pearled wheat are generally used, as the bran is blown off       in the second category, dehydration is accompanied by
during the process and would be unsightly in the product. The        stabilization of the microbial charge and flora, sometimes
degree of expansion obtained with gun puffing (15-20 times) is       preceded by their prior development.
much greater than with oven puffing.                                    It is during the drying process that the characteristic colour
    Puffed products must be kept at less than 3% moisture to         and flavour of the products are formed. The operation is usually
maintain crispness. The more the product is expanded, the more       lengthy and may take as long as a year for pieces in their
critical and harder the levels are to maintain. Thus, gun-puffed     original form and of superior quality. For pieces with low
products require special packaging. (2000)                           equilibrium moisture content, the drying conditions are
                                                                     generally more drastic, and the operation is rapid. Accordingly,
                                                                     microbial development is arrested, and chemical and enzyme
                      10. Dehydration                                reactions are slowed down very considerably. The substances
                                                                     resulting from such reactions during storage do not, as in the
   Dehydration is one of the most ancient processes for              case of products in the second category, help to develop
preserving meat. Practised in America and Africa, often in           agreeable flavours, but cause deterioration of the organoleptic
association with curing, it affords a whole range of speciality      quality of the product
foods. In Europe, the products preserved by this method                 The quantities of foodstuffs processed by these methods are
include: among stuffed goods, dried sausage, salami, and other       substantial. Among these products, two are worthy of special
types of sausage; of products where anatomical integrity is          consideration, namely dried sausage and cured ham. Besides
preserved, cured ham, and related products; and also other           these products, we shall also consider the case of dehydrated
forms of dried meat, and lard.                                       meats, because of the theoretical interest they offer. (2000)
   While the desired objective for cooked products is to ensure
the maximum degree of cohesion of the constituents by limiting
transfer of moisture and lipids, conversely, for dried products,
the aim is to facilitate transfer of water, while restricting its
activity, since the presence of excess moisture is detrimental to
the keepability of the products. The extent of dehydration of the