Английский язык (Пищевой профиль). Учебное пособие

bottom yeasts, top yeasts and distillery yeasts. The first two are culture plants. Wine and brewer’s yeasts refer to the bottom yeasts; distillery yeasts and baker’s yeasts and some brewer’s yeasts relate to the top yeasts. The difference between the top and the bottom yeasts is in rapid fermentation of the top yeasts.

The top yeasts are separated on the surface as a thick foam which remains till the end of fermentation. They precipitate in a thin layer on the bottom of the fermenting vat.

The characteristic feature of the bottom yeasts is that they settle down in a thick layer on the bottom of the fermenter.

There are different species of yeasts. The main species of the top yeasts used in alcohol production are those having a great power of attenuation and producing large amount of alcohol. The top yeasts used in baker’s yeasts production should propagate quickly and have a great dough raising power and good keeping qualities.

The bottom yeasts used in brewing should be quite pure and have a flocculating capability. The top yeasts used in wine-making are capable of suppressing other microorganisms and give to wine its bouquet.

FAO'S SMALL-SCALE MODULAR SLAUGHTERHOUSE

The Animal Production and Health Division of the Food and Agriculture Organization of the United Nations (FAO) has developed a model project for village meat industry in which one of the main components is a smallscale modular slaughterhouse. The design incorporates the use of locally available construction materials and unsophisticated equipment. The slaughterhouse can be built in modules, adding units to the central slaughterhall for operations such as byproduct utilization, meat preservation, processing and butchering. Designs have also been prepared for the construction of a meat market in order to facilitate the integration of production, processing and marketing.

It is intended that from the basic nucleus a number of small-scale industries be developed consecutively, e.g. meat preservation by lowcost technologies, traditional tanning, handicrafts based on hides, skin, bone and horns, etc. The objective is to increase employment, in particular for rural women, create market outlets for livestock products and increase the income of small producers.

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The project could become a focus for farmer organization and a centre of technical assistance for producers. The organization of small producers is indispensable to ensure their participation and for the success and continuity of the project.

FAO is promoting the establishment of slaughterhouses of this type in some rural areas because this would increase the availability and quality of meat, improve the utilization of by-products, avoid rural migration and increase employment. The slaughterhouses may, therefore, constitute a tool for rural development, increasing the income level in the countryside and villages, thus improving the living conditions of the rural communities.

Rural slaughterhouses can also facilitate veterinary control of livestock (ante-mortem inspection) and carcass meat (post-mortem inspection). Slaughtering can be organized to follow a determined daily or weekly time schedule for which compulsory veterinary controls can be arranged. In addition, adequate technical facilities for efficient meat inspection can be provided, i.e. vertical position of the carcasses and special platforms for the personnel. Special hooks or inspection tables can be provided for the inspection of internal organs.

The detailed design for a small-scale modular slaughterhouse was developed by FAO. It includes designs, specifications, and schedule of quantities for a slaughterhouse and meat market suitable for small communities.

Provision is made for slaughter of all species: cattle (or buffalo), sheep, goats and pigs, though because of space limitations, concurrent slaughter of different species is not possible. The abattoir capacity will be dependent on the mix of animals being slaughtered. Daily throughputs of approximately 10 large stock (e.g. cattle) or 50 small stock (sheep, goats or pigs) or a combination thereof could be achieved with this design.

The facilities are divided into modules which can be combined as required to suit a particular location.

The following modules are included:

·Lairage

·Slaughter floor

·Chiller

·Tripe room

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·Meat cutting and processing room

·Solid waste and blood disposal

·Hides and skin processing

·Effluent disposal

·Electric light and power

·Water supply

·Meat market

PRINCIPLES OF MEAT DRYING

Drying meat under natural temperatures, humidity and circulation of the air, including direct influence of sun rays, is the oldest method of meat preservation. It consists of a gradual dehydration of pieces of meat cut to a specific uniform shape that permits the equal and simultaneous drying of whole batches of meat.

Warm, dry air of a low humidity of about 30 percent and relatively small temperature differences between day and night are optimal conditions for meat drying. However, meat drying can also be carried out with good results under less favourable circumstances when basic hygienic and technological rules are observed. Intensity and duration of the drying process depend on air temperature, humidity and air circulation. Drying will be faster under high temperatures, low humidity and intensive air circulation.

Reducing the moisture content of the meat is achieved by evaporation of water from the peripheral zone of the meat to the surrounding air and the continuous migration of water from the deeper meat layers to the peripheral zone.

There is a relatively high evaporation of water out of the meat during the first day of drying, after which it decreases continuously. After drying the meat for three or four days, weight losses of up to 60-70 percent can be observed, equivalent to the amount of water evaporated. Consequently, moisture losses can be monitored by controlling the weight of a batch during drying.

Continuous evaporation and weight losses during drying cause changes in the shape of the meat through shrinkage of the muscle and

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connective tissue. The meat pieces become smaller, thinner and to some degree wrinkled. The consistency also changes from soft to firm to hard.

In addition to these physical changes, there are also certain specific biochemical reactions with a strong impact on the organoleptic characteristics of the product. Meat used for drying in developing countries is usually derived from unchilled carcasses, and rapid ripening processes occur during the first stage of drying as the meat temperature continues to remain relatively high. For that reason the specific flavour of dried meat is completely different from the characteristic flavour of fresh meat.

Undersirable alterations may occur in dried meat when there is a high percentage of fatty tissue in the raw meat. The rather high temperatures during meat drying and storage cause intensive oxidation (rancidity) of the fat and an unpleasant rancid flavour which strongly influences the palatability of the product.

Meat drying is a complex process with many important steps, starting from the slaughtering of the animal, carcass iming, selection of the raw material, proper cutting and pre-treatment of the pieces to be dried and proper arrangement of drying facilities. In addition, the influence of unfavourable weather conditions must also be considered to avoid quality problems or production losses. The secret of correct meat drying lies in maintaining a balance between water evaporation on the meat surface and migration of water from the deeper layers.

In other words, care must be taken that meat surfaces do not become too dry while there is still a high moisture content inside the meat pieces. Dry surfaces inhibit the further evaporation of moisture, which may result in products not uniformly dried and in microbiological spoilage starting from the areas where the moisture content remains too high.

SMOKED DRIED MEAT

Smoking of meat is a technique in which meat is exposed directly to wood smoke which may be generated by a variety of methods. In smoke produced from wood there are various substances which contribute to the flavour and the appearance of the smoked meat product and which have a certain preserving effect on the product.

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However, the preserving effect of common smoking is not very significant when storing the product without a cold chain. On the other hand, intensive or prolonged smoking may considerably increase the shelf-life of the product, but it also has an unfavourable effect on flavour. Whereas a light smoke aroma generally enhances the organoleptic properties of the product, intensive smoking has a negative influence on the quality, especially in the case of prolonged storage in which concentrated smoke compounds develop increasingly unpleasant tarry flavours.

In view of the above, smoking in order to preserve meat can only be considered as an emergency measure when no other preservation methods can be carried out. This may be the case during wet weather or generally under a humid climate, or when the preservation has to be completed as fast as possible because of the need of immediate transport, for instance after game-hunting.

Intensive meat smoking is always a combination of two effects, drying the meat by reducing its moisture content through hot air and the condensation of smoke particles on the meat surface together with their penetration into the inner layers of the product. Both have preservative effects and prolong the shelf-life of the product.

To smoke the meat, large strips and/or pieces, with and without bones, are dried by smoking in special drying/smoking places. The smoke is produced in these cases by glowing wood. Often, meat is prepared quickly by drying and smoking over a fire. In this case, the meat is not only smoked, but "half-cooked" or roasted. Normally, meat from this treatment is not well prepared and has to be consumed soon after drying, otherwise it will spoil quickly.

The quality of traditionally smoke-dried meat is generally poor. This is not only owing to poor meat quality or inadequate smoking devices, but mainly because smoke-drying is a rather rough treatment for the meat. The process is fast and has a certain preserving effect, but at the cost of quality.

Quality losses are even more obvious when failures in preparing the raw material occur. When, for example, the thickness of the meat parts to be smoked ranges from about 3 cm to 15 cm, uniform drying will not be achieved. The smaller pieces will be overdried and the thicker ones may still remain with a high moisture content in the product centre.

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The results of faulty drying and smoking are a too strong smoke flavour, lack of rehydration capacity of the smaller parts and fast spoilage of the thicker parts. For effective smoke-drying, the meat thickness should not exceed 7 cm to achieve products which are stable for a certain period without refrigeration.

Apart from primitive smoking places with just a fire below the meat, the construction of special smoking kilns has been suggested for smoke-drying of meat.

The effect of light smoking could be of interest for the production of dried meat. Light smoking is not suitable for meat preservation without a cold chain, but it adds a smoke flavour to the product and inhibits the growth of moulds and yeasts on the product's surface owing to the fungistatic smoke compounds. Thus light smoking may be used for the prevention of growth of moulds during the storage period of dried meat, especially under humid climatic conditions.

RAW AND DRY SAUSAGES

Germany, more than any other country, has influenced the production of sausage throughout the world. The industry in Germany has developed a system of classifying sausages. In principle, this classification is based on the temperature treatment of either the final product or the raw materials.

Most cooked sausages consist of fine-meat emulsion, but many combinations are made with either semi-coarse lean or semi-coarse fat and with both. Among the salamis, combinations of semi-coarse lean and fat and coarse-lean and fat are seen. Many similar kinds of sausage have different names. The terminology of sausage is rather complex as the system of naming is based on association with localities, special occasions, sensory perception, etc.

The main equipment for raw and dry sausage production consists of the mincer and/or bowl chopper, vacuum mixer, stuffer, climate chamber and, in a number of cases, the smokehouse. In bigger operations the vacuum chopper is gaming popularity. In Italy and in some parts of eastern Europe the mincer is the exclusive machine for comminution. In most other countries, and particularly for those factories using deboned frozen meat, the bowl chopper is applied. In some cases, part of the lean

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meat is minced and blended with the balance of the chopped meat and the fat, either at low speed in the bowl chopper or in a vacuum mixer, to achieve a better binding and coherence.

The sausage mix may be stuffed at a lower temperature than was formerly used. The fast continuous stuffers must have a low temperature (- 4 °C) to prevent smearing. In some factories, the stuffed sausages are hung overnight in a cool place (5-10 °C) to avoid a too rapid change in temperature before they are transferred to the fermentation chamber. Stuffing is done in natural, artificial and collagen casings.

Raw sausages like Mettwurst and Teewurst are fermented in airy rooms for the formation of a stable color and then smoked to the desired color and taste. Generally, coarse products such as some types of Mettwurst are cold smoked, whereas very fine and spreadable sausage such as Teewurst are warm smoked.

For dry sausage production on a large scale, mincing, blending and stuffingare performed continuously. After blending, the sausage mix is automatically transferred by a plunger into stainless steel cylinders which are transported by rail and automatically fitted to the stuffers.

Fermentation, drying and smoking are done at temperatures between 12 and 15 °C during times ranging from weeks to several months. Fermentation is performed at temperatures between 20 and 25 °C and relative humidity (RH) of 92—95 %. The subsequent smoking and drying are done at temperatures preferentially below 20 °C and gradually decreasing RH down to about 78 %. This method takes from 5 days to 3 weeks. Limited amounts of glucono delta lactone (GDL) are used to acidify the product. However, starter cultures are more frequently used.

Fresh sausages, such as pork and beef sausages, are raw items and not fermented. As far as Europe is concerned, their production is limited to the United Kingdom. They are made in the bowl chopper at temperatures not exceeding 5 °C, stuffed into medium hog casing, wrapped in plastic film, distributed under refrigeration and fried by the consumer. Some types of fresh sausage are artificially colored by using pink rusk. Bratwurst, which is quite popular in Austria, Switzerland, Germany and the Scandinavian countries (known as Medister), was originally a fresh sausage. At present, however, most Bratwurst is cooked by the manufacturer.

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The raw materials normally used are either lean pork or beef or a combination thereof, and hard pork fat, mostly pork-back fat. The use of mutton is rare. In Scandinavian countries, excellent dry sausages are produced from reindeer meat. For cheaper types of dry sausage, hearts, rinds and, in some cases, rind emulsions are used. Formulations range between 30-50 % fat.

For fresh sausage the main ingredients are either lean pork or beef and pork fat, and a relatively high percentage of extenders. Rusk, flour, skimmed milk powder, soy isolate and concentrate, milk proteins and dextrins are used in countries where extenders are permitted. Normal additives are salt, nitrate, nitrite, polyphosphates, ascorbic acid, mono and diglycerides of fatty acids derived from animal fat, dextrose, malto dextrins, sucrose and lactose. Wine is used in some special types of salami.

The most popular spices are pepper, paprika, mace, garlic, cardamom and cloves. For fresh sausage production, soaked bread, cooked rice and potatoes have been used. At present, rusk and some starch are more frequently applied. Amounts up to 10 % or higher of these ingredients are not unusual.

SAUSAGE MADE WITH COOKED INGREDIENTS

On the European continent most liver-and-blood sausage is made of precooked fat, meat, rinds, tripe and stomachs. Liver is not precooked. In the United Kingdom the use of precooked ingredients is not common practice.

On the continent, liver is chopped with a part of the salt and curing ingredients. After some chopping, bubbles begin to form and precooked fat and broth are introduced as this time. Chopping is continued until the desired fineness is almost achieved. Then the balance of the salt and spices is added. At a temperature between 35 and 50 °C, the sausage mix may be stuffed as a fine liver sausage or used as a base for other liver sausage. By chopping in precooked meat, or mixing in pieces of cooked meat, fat or liver, many different types of liver sausage are made.

For liver sausage containing a certain amount of broth, water in which fat and the other ingredients are precooked is used as the broth. Both broth and fat are brought in the bowl chopper, where the fat is

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emulsified by means of sodium caseinate. The prechopped liver is then added to the emulsion, and after a short chopping the sausage mix is ready. The liver may also be minced and added to the emulsion. Finally, the mixture is passed through a mill. This method is convenient and allows more recipe variation than the conventional process. More stable products are obtained for high temperature baking or canning. This technique is used for the incorporation of fresh fat in the United Kingdom.

Sausages are stuffed either in natural or artificial casings. For some types of liver sausage a fat lining may be applied in artificial casings or molds.

Fat, meat and rinds are precooked for use in blood sausage. The blood is cured with salt, nitrite and either citrate or phosphate to prevent clotting. Precured and aerated blood results in sausage with a pink color. Otherwise, the sausage becomes black on cooking. The pretreated blood is warmed and chopped with the rinds, and, in some types, with precooked meat or cubed fat. During cooking and cooling, sausages are turned to achieve an even distribution of cubes. Large casings, hog stomachs and molds are utilized.

Jellied products are made with either pure gelatin or cooked rinds as the gelatin base. Cooked rinds are finely ground and sifted after cooking at about 80 °C. For improved flavor and gelatin strength, vinegar or white wine may be added. The cubes of meat and the fat are cooked, precured if a pink color is wanted, then mixed with the rind jelly and seasoning. The product is then stuffed into casings or hog stomachs, cooked and cooled. According to another technique, the product is cooked once more and hot filled into clean molds and then chilled.

Liver sausage may consist of a 50:50 liver-to-fat ratio plus seasoning, down to as little as 15 % liver with 30 % broth, 35 % fat, some cooked rinds and extenders. The product ranges from spreadable to sliceable, depending on the amounts and proportions of meat, collagen and binders. Other variations are created by adding coarse meat, liver and pieces of fat to the fine sausage emulsion. The degree of fineness of the meat and fat ingredients, as well as the seasoning, determines the type of liver sausage.

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Ingredients for blood sausage include blood and cooked rinds as well as cubed fat, tongue, kidney and pork belly. For cheaper types, tripe, lungs and stomachs may be used.

For jellied products the principal raw materials are rinds, gelatin, lean meat trimmings, pigs foot, calves foot, defatted head meat, firm fat tissue and, in some cases, hearts.

For liver sausage the following extenders are used: sodium caseinate, skimmed milk powder, wheat flour, soy protein concentrate, soy protein isolate and some potato starch. Egg white, whole egg and blood plasma are occasionally used in liver sausage.

The most popular spices for liver sausage are pepper, nutmeg, marjoram, mace, pimento, cloves, ginger, cardamom, cinnamon, onions, shallots, truffles and pistachios.

Cereals such as barley and rye flour are used in blood sausage. The most prevalent spices in blood sausage are pepper, marjoram, cloves, pimento, thyme, cinnamon, ginger, onions and coriander.

In jellied products, flavorings utilized are pepper, pimento, marjoram, ginger, cloves, kummel, celery, bay leaf, vinegar and white wine.

SAUSAGE COOKED AFTER FORMULATION

The mincer, bowl chopper, vacuum mixer, blender, mill and stuffer are the machines most used. Small quantities are manufactured in batches, while large quantities are prepared semi-continuously. The preblending system is gaining popularity in Europe. Although originally a means to obtain uniform raw material, the combination of mincer, preblender, mill and stuffer now provides a more or less continuous production system. For critical products the conventional chopper mixer stuffer process is preferred. Many types of casings are used, but in central Europe many small sausages are produced in natural casings.

Pork and beef are the most popular meat ingredients, with limited use of mutton, horse and poultry. Variety meats such as hearts, diaphragm, tripe, pork skin, stomachs, etc. are allowed in most countries, although not in every product. In some countries, sausage products are divided in two or three quality categories. For each of them the raw materials which can be used are defined. Mechanically deboned meat is

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