Профессионально-ориентированное чтение для магистров и аспирантов пищевых специальностей университета (сборник текстов)

Министерство образования и науки Российской Федерации Восточно-Сибирский государственный технологический университет

Кафедра иностранных языков

Профессионально-ориентированное чтение для магистров и аспирантов пищевых специальностей университета. (сборник текстов)

Методическое пособие предназначено для аудиторных и внеаудиторных занятий по английскому языку со слушателями групп по подготовке к кандидатскому экзамену. Тексты, включенные в сборник, заимствованы из оригинальных научных изданий и подверглись лишь незначительным сокращениям, их грамматическая структура и лексика сохранены полностью. Тексты, в зависимости от их объема и содержания, сгруппированы в V разделов для использования в разных учебных целях, таких как: - чтение с общим понимаем прочитанного, чтение и передача содержания на русском или английском языке, - полное понимание прочитанного (письменный перевод), - чтение текста как основа для построения высказывания.

Составитель: Михедова Л.Г. Ключевые слова: Nutrition , microorganisms, environment, cereals, dehydration, health

Издательство ВСГТУ Улан-Удэ 2004

Section I Texts for class reading and translation in writing 1. Function and nutrition guide fiber ingredient selections Increased dietary fiber content has become a dominant marketing claim for new product introductions. Because fiber is not absorbed, products high in fiber are generally much lower in calories. And because of the ability of certain fiber materials to reduce serum cholesterol, a product rich in dietary fiber offers the dual attractions of fat and calorie reduction along with the potential for improving cardiovascular circulation. This shift in development effort is further evident at the ingredient level, where suppliers of traditional vegetables, fruits and grains have repositioned their products to stress fiber content and the healthy image this implies. At the 1988 Food Expo, held June 19-22 in New Orleans, attendees found twice the number of exhibitors offering dietary fiber ingredients compared to those exhibiting at Food Expo '87. Consumer demand for high-fiber foods continues to grow and extend beyond traditional dietary fiber sources such as breads and muffins. Over the past four years, extensive research on fiber and the digestive cycle has clarified our understanding of various ways in which fiber affects the absorption and digestion of several significant nutrients found in foods. In addition to the conventional cereal bran sources, legume hulls, and similar husk-like fibers, high-fiber ingredients now include prunes, apples, pears, citrus, several of the tree and plant gums, and even a fiber obtained as a by-product of tofu production. Suppliers of traditional fiber ingredients have extended their product lines to include specially bran blends, or fractionated products with higher-than-customary levels of protein. (1600)

2. Physical properties of fiber. Unique physical properties possessed by various sources of fiber are important in determining certain physiological responses. Some of these properties and the physiological responses elicited by specific fiber fractions. Bacterial degradation, which is relevant to only the polysaccharide fraction, is the first of these properties. Dietary fiber cannot be enzymatically degraded in the mammalian small intestine; it is, however, fermentable to varying degrees of degradation within the large bowel. The degree of degradation varies considerably among the polysaccharides. For example, pectins, mucilages, and gums appear to be completely degraded, whereas cellulose is only partially broken down. Furthermore, the extent of breakdown may be related to the physical structure of the plant: fiber from fruits and vegetables appear to be more fermentable than that from cereals and grain. The extent of bacterial degradation has several important implications: (1) the short-chain fatty acid by-products may influence the physiological responses to fiber; (2) The fermentation process can lower the pH of the large bowel and may affect microbial metabolism. (1400) Table 5 – Physiological Responses affected by the physical properties of fiber fractions. Physical property

Fiber fraction

Bactenal degradation

Polysaccharides

Water-holding capacity

Polysaccharides with polar groups

Physiological response Production of shortchain fatty acids, flatulence and acidity Effect on nutrient absorption fecal weight and rate of transit in stomach and

Adsorption organic materials Cation exchange

of Lignin Pectin Acidic polysaccharides

small intestine Binding and excretion of bile acid

3. Dried sausage Dried sausage is an uncooked fine meat product, which is fermented and dried and is composed of roughly 2/3 lean meat and 1/3 fat. The lean meat may be derived from different animal species, although pork and beef are most frequently used. The fat, generally pork fat, must be firm and non-oily, and back fat is usually employed. To these two principal constituents are added sodium chloride, nitrates and/or nitrites, sugars, spices or aromatic compounds, and lastly polyphosphates, ascorbic and lactic acids, colouring matter, and ferments. The first stage in the manufacture of this product is grinding; this is performed at a low temperature, slightly above 0ºC for muscle tissue and slightly below for fatty tissue. Under these conditions, clean cutting of fat is possible and the formation of a puree or melting of the fat can be prevented. Grinding is most often performed simultaneously on these two primary materials, sometimes after preliminary salting, either on the two constituents in a chopped state, or else on the lean meat alone. It facilitates protein solubilization. The mixture of the lean, the fat, and the other ingredients then undergoes a final process referred to as mingling. The mix, sometimes after a resting phase of several hours at O/ + 5ºC, is then stuffed in either natural gut or artificial casing material. A draining stage can follow, before stoving for a period of 1-5 days at 85-90% relative humidity and temperatures in the range 20-28°C. Primarily, this promotes a sudden explosive growth of bacteria, and also initiates dehydration. The final operation is drying, which is performed

gradually. Its duration varies with the diameter of the product and the extent of drying required, but on average it lasts from 4 to 6 weeks. A relative humidity of 75- 85% is maintained in the dryer, with temperatures in the range 12-16°C. Throughout the drying operation, reactions including maturation and desiccation proceed and impart their particular characteristics to the final product. (1700) 4. Effect on plasma lipids and lipoproteins of replacing partially hydrogenated fish oil with vegetable fat in margarine Partially hydrogenated oils, both vegetable oils and fish oils, have for a long time been important ingredients in margarine production. Accordingly, the consumption of transfatty acids has increased considerably in industrialized countries since the beginning of this century. Like saturated fatty acids, transfatty acids from partially hydrogenated oils raise plasma total- and LDL-cholesterol levels and in addition lower plasma HDLcholesterol and increase lipoprotein(a) (Lp(a)) levels. Concerns, have, therefore been raised as to the continued use of partially hydrogenated oils in margarine production. We have previously shown that partially hydrogenated fish oil (PHFO) is at least as potent as butterfat and significantly more potent than partially hydrogenated soyabean oil in raising plasma total- and LDL-cholesterol levels. In addition it reduces HDL-cholesterol and increases Lp(a) levels. It would therefore seem prudent to reduce the use of PHFO in margarine products. PHFO has functional properties, however, that make it particularly suitable for the baking industry which requires margarines of certain hardness, as well as for household food preparation. It is, therefore, of interest to find alternative fat blends that maintain the functional properties of the margarine

but improved effects on plasma lipids. The aim of the present study was to compare the effects on plasma lipoproteins and haemostatic variables of two hard test margarines with similar functional properties, one traditional margarine based on PHFO and one based entirely on vegetable oils. (1500) Abbreviations:

contrast, growth of microorganisms is impossible below a limiting value of Aw1. In addition to Aw, a number of other parameters influence the growth of microorganisms. The most important of these, for meat technology, are: the oxygen partial pressure, pH, temperature, and the presence of nitrite and sodium chloride. The data for the parameters referred to above (optimum and limiting values of Aw are thus not absolute, owing to the influence of these other factors. (1200)

PHFO – partially hydrogenated fish oil. Lp(a) – lipoprotein (a) LDL – Low – density lipoprotein HDL – High-density lipoprotein

5. Influence of water activity on growth of microorganisms

Section II Texts for home translation in writing

We have already emphasized that water takes part in two major transformations in foodstuffs: enzymatic and oxidative changes. Its role is equally important in the growth of microorganisms. Many studies have addressed this. It emerges that the growth and metabolic activity of microorganisms, including bacteria, yeasts, and moulds, depend essentially on available water. A reduction in the activity of water causes the following modifications to the growth curve obtained at optimal activity Aw1 for microbial growth:

6. Environmental Problems: Why the Concern?

(i) (ii) (iii)

increased duration of the lag phase; reduced rate of growth (exponential phase); reduced number of organisms during the stationary phase.

Different groups of microorganisms have different values of AW1, the optimal activity for growth. Table 3.7 gives details, as we can see, the optimum range is between 0.92 and 0.99. By

Americans are concerned about environmental problems for two general reasons. First, many environmental problems are public health problems. Increased air and water pollution may compromise the health of the entire population. The second reason for concern is a growing fear that human societies are creating so many environmental problems that the overall stability of the earth's ecosystems may be threatened, rendering the planet unfit for human habitation. Because many environmental problems, like exposure to toxic chemicals, are relatively invisible, they are easy to ignore. However, as we all know, ignoring a problem does not make it go away. Picture in your mind a warm summer day. Imagine you are outside mowing a lawn, washing your car, or having a barbecue with friends. Months ago a contractor hired by your state's department of transportation resurfaced the street in front of your house. Unbeknownst to you, ash from a municipal

garbage incinerator was illegally mixed with the resurfacing compound. Incinerator ash often contains numerous heavy metals and toxic chemicals including dioxin, possibly the most deadly chemical known to humanity. A dose of dioxin, one hundredth the size of a grain of salt, causes immediate death to a guinea pig. For months, evening thunderstorms, which brought you relief from hot summer days, washed contaminants from the street into your yard. You have been exposed to toxins. Your health and that of your family and neighbors may have been severely compromised. You probably were completely unaware of the presence of dioxin in your yard. Should you develop cancer later in life, you may never know if exposure to dioxin was the primary cause. While the above scenario may sound improbable, many similar events have occurred across the United States. In numerous cases, thousands of residents have been forced to permanently evacuate their homes because toxic contamination cannot be adequately removed. The evacuation of communities, as a result of chemical contamination, has become a relatively commonplace event in our society. Scores of evacuations such as the 1990 relocation of the residents of Ponca City, Oklahoma occur each year. (2000) *** 7. Human exposure to toxic substances occurs more frequently than most people recognize or would like to admit. Trace levels of a variety of contaminants are routinely found in the human body. One estimate suggests that over 90 percent of all cancers are caused by exposure to toxic substances. Other estimates speculate that globally over 30 million lives are lost annually as a direct result of human mismanagement of the environment. As pollution levels increase, humans are forced to modify their behaviors. Many of the world’s residents can no longer get

up each morning and assume that they can routinely go about their normal daily activities. Already, the day has come when children in many cities must be kept inside on days when air pollution levels exceed healthy limits. In Mexico City, pollution has become so acute that the daily activities of millions of people are restricted on an increasingly frequent basis. Restrictions are routinely placed on automobile use, and children are frequently prohibited from going to school on certain days. Pollution levels often exceed international standards. It is not uncommon for ground level ozone in Mexico City to reach 297 on the metropolitan air quality index. According to the World Health Organization, an ozone reading of 300 poses a serious health risk. Exposure to this level of ozone can result in memory loss and severe respiratory problems. Exposure to toxins which have leached into the soil or groundwater is only one of many ways in which North Americans come into contact with extraordinarily dangerous substances. Transportation related accidents occur even more frequently than chemical leaks at manufacturing facilities. Nationwide, more than 4 billion pounds of hazardous materials are shipped by rail each year. On any given day there are over 250,000 shipments of hazardous chemicals. In 1989, there were over 200 rail accidents involving hazardous substances. In many cases thousands of people had to be temporarily evacuated from their homes. A typical accident occurred in June of 1992 when 14 rail cars fell from a bridge and spilled over 21,000 gallons of benzene into the Nemadji river in Minnesota. Fearing that benzene exposure would cause central nervous system and lung damage, National Guard and Army Reserve troops were called in to help evacuate over 50,000 people from Duluth and surrounding communities. This type of accident threatens virtually every American community. (2000)

8. Methods of Analysis Because the term "dietary fiber" encompasses such a diverse group of compounds, the analysis for its content in foods may be achieved with several approaches. Included among these are the following three methods: Extraction Methods may be used to isolate various fractions which are then gravimetrically quantified. Formerly the Association of Official Analytical Chemists (AOAC) method, crude fiber analysis is based on extraction with acid and alkali. As this procedure does not measure any specific carbohydrate or group of carbohydrates, it does not accurately estimate the dietary fiber content, nor can it be quantitatively related to the fiber content of foods. Neutral and acid detergents are the bases of another, extraction method the Neutral Detergent Fiber procedure (NDF), for isolating fractions. Originally developed for analysis of animal forages, this method was modified for analysis of human foods which are high in fats, protein and starch. It has the advantage of being relatively rapid and is useful for estimating the content of insoluble structural polysaccharides and lignin. A modified NDF is an official method of the American Association of Cereal Chemists. Analysis of the Individual Components of fiber constitutes the second approach for determining the fiber content of food. The Southgate procedure, the best known of this type of analysis, involves removing the individual fractions through a series of extraction steps. After hydrolyzing the fractions, the sugar components are determined by gas-liquid or liquid chromatography. Although this approach is difficult and timeconsuming, the detailed analytical data provided by these methods are invaluable in understanding the variability in physiological response induced by different sources of fiber.

Rapid Enzymatic Procedure – the third approach – is intended to provide a single value for the soluble and insoluble fiber content of the food. Currently under review and likely to be approved by the AOAC this procedure involves enzymatic removal of protein and starch from fat-extracted food. The residue is corrected for ash and protein content, and the fiber is determined gravimetrically. Although rapidly yielding results, this gravimetric procedure does not comprehensively determine individual fiber components. (2000)

9. Puffed Cereals For the puffing of cereals, i.e., greatly decreasing their bulk density, two general methods are used. The first is the sudden application of heat at atmospheric pressure. In this technique, water is vaporized before it has time to diffuse to the surface of the piece. The internal vaporization then expands, or puffs, the product. The second type is the sudden transfer of a piece containing superheated water to a lower pressure, thus allowing the water to suddenly vaporize. Both types depend upon water going to a vapor as the driving force. The key to the degree of puffing is the sudden change in temperature or pressure. Examples of processes using these techniques are given below. Oven-puffed rice is an example of the sudden application of heat. Milled rice is cooked at 15 psi until it is uniformly translucent, dried to 30% moisture, tempered for 24 hr, and dried to 20% moisture. The intact kernels are subjected to radiant heat to plasticize the outside of the kernel. The kernels are bumped (to destroy their internal structure) and again tempered for 24 hr. Then they are passed through the oven at 300°C for about 30 sec. In this technique, the expansion is not great, just two to five times. Pressure-puffed (often referred to as gun-puffed) products can be made from a dough mixed and steam-cooked to about

40% moisture. The dough is forced through an extruder to give it a specific shape and is dried to 12-15% moisture. The pellets are then loaded into guns or popping vessels. These guns are about 30 in. long and 6 in. in diameter. They are sealed, rotated, and heated to 425°C. Pressure may build to 200 psi. The trip valve is opened and the material explodes out. Many variations are possible, using different flavors, shapes, types of doughs, etc. Wheat and rice kernels can also be gun-puffed. Milled rice and pearled wheat are generally used, as the bran is blown off during the process and would be unsightly in the product. The degree of expansion obtained with gun puffing (15-20 times) is much greater than with oven puffing. Puffed products must be kept at less than 3% moisture to maintain crispness. The more the product is expanded, the more critical and harder the levels are to maintain. Thus, gun-puffed products require special packaging. (2000)

10. Dehydration Dehydration is one of the most ancient processes for preserving meat. Practised in America and Africa, often in association with curing, it affords a whole range of speciality foods. In Europe, the products preserved by this method include: among stuffed goods, dried sausage, salami, and other types of sausage; of products where anatomical integrity is preserved, cured ham, and related products; and also other forms of dried meat, and lard. 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

products at the end of the meat chain can be more or less complete. It is customary to classify food products into three categories according to their moisture content and water activity. Food products can have high intermediate and low equilibrium moisture contents. Fresh meat belongs to the first category; dried sausage, cured ham, and dried beef to the second; and lard to the third. Forms of dried meat prepared in Africa and America usually also belong to the third category. For products in the second category, dehydration is accompanied by stabilization of the microbial charge and flora, sometimes preceded by their prior development. It is during the drying process that the characteristic colour and flavour of the products are formed. The operation is usually lengthy and may take as long as a year for pieces in their original form and of superior quality. For pieces with low equilibrium moisture content, the drying conditions are generally more drastic, and the operation is rapid. Accordingly, microbial development is arrested, and chemical and enzyme reactions are slowed down very considerably. The substances resulting from such reactions during storage do not, as in the case of products in the second category, help to develop agreeable flavours, but cause deterioration of the organoleptic quality of the product The quantities of foodstuffs processed by these methods are substantial. Among these products, two are worthy of special consideration, namely dried sausage and cured ham. Besides these products, we shall also consider the case of dehydrated meats, because of the theoretical interest they offer. (2000)

11. Methods in use in the brewing industry to reduce or control microbial contamination Chlorine: this should not be used for water that goes into the beer. Compounds which act as a source of chlorine either directly as in chlorination, or indirectly through hypochlorite, can produce phenolic taints in beer and highly volatile halogenated hydrocarbons such as trihalomethanes (THM). Chlorinated town water supplies require treatment before use. -Chlorine dioxide functions as an oxidising agent. As a gas in water it does not release halogens which could react to produce taints. Chlorine dioxide is used at maximum level 0.5 ppm, which is its maximum permitted level in potable water, and is used to treat final rinse water after disinfection. - Ozone: this treatment has a strongly oxidising effect which kills micro-organisms. - UV treatment: UV light in the wavelength of 200 to 280 nm destroys the DNA in micro-organisms, provided the correct doze rate is applied. Unlike chemical treatment, it has no residual action and is limited to the point of application and therefore the water should be treated immediately before use. However, to be effective the water must be colourless and free from suspended material or the sterilisation will be ineffective. - Sterile filtration: physical water treatment, such as reverse osmosis and distillation, will produce a sterile product. Distribution through water mains and when using other water treatments can result in micro-organisms being present in the dilution and cleaning waters. Disinfectant and sterilisation is often applied to final rise waters and critical dilution water such as those supplying a culture plant or for post filter dilution. Sterile filtration through a 0.2 micron filter (in practice 0.45 micron may also be used) to produce a sterile water at point of use. (1500)

12. Breakfast Cereals Most oats that are consumed directly as food are served as breakfast cereal. Of the type that must be cooked, the most popular by far is rolled oats. The process used to make rolled oats is given in Fig. 1. The cleaned oats are treated with dry steam at 100°C. This reduces the moisture content to about 6% and inactivates enzymes, particularly the lipase system. Oats are high in lipid and very susceptible to rancidity. Drying the hulls makes them more brittle and therefore easier to remove. The next step is to separate the hulls from the groats and the whole oats that were not dehulled in the process. In general, removing the hulls is not difficult; they are light and can be separated by aspiration. It is much more difficult to make a clean separation of groats from whole oats. Even a small percentage of whole oats remaining with the groats is unacceptable. Hulls in rolled oats are not palatable. The groats are then rolled, or flattened, with large, very heavy rolls to give the rolled product. Flaked whole groats take 10-15 min to cook. The cooking time (i.e., the time required for the hot water to penetrate to the center of the flake) is determined by the thickness of the flake. Of course, the cooking time is controlled by the thickest point, and therefore a uniform piece is desirable. To obtain rolled oats that cook more quickly, one must produce a thinner flake. This is accomplished by cutting the groats into two or three pieces before flaking. The smaller pieces give a thinner flake that cooks faster (3-5 min), although the cooked cereal will not retain its quality if held under hot conditions such as on a steam table (the product becomes a gruel). Thus, we have the classic trade-off between cooking time and product

stability. Newer products are available that cook just upon addition of boiling water. Examination shows that these are very thin, and such products have little or no stability to storage after cooking. (1500).

Section III Texts for class reading and rendering in Russian 13. Defining Fiber Ingredients Fiber is a complex group of polysaccharides whose components include: cellulose, hemicellulose, pectin, and lignin as the major fractions. Fiber also can be subdivided into a variety of materials exhibiting basic differences in their chemical, physical, and physiological effects. Among the more important of these different properties is that of relative solubility. Dietary fibers can range from insoluble (alpha cellulose) to almost totally soluble (pectins, vegetable gums) materials. Solubility appears to have even greater significance as we learn more and more about how various fibers modify enzymes, alter mineral absorption, and otherwise affect digestion. Another important variable characterizing dietary fiber is the particle size or form in which it is available. Generally, defining the relative ease of introducing a particle into a food system or controlling uniformity of dispersion are only concerns with insoluble fiber ingredients. In the case of soluble fibers, or mixed soluble and insoluble fiber ingredients, particle size can affect end properties ranging from apparent viscosity to taste, and dissolution to heat transfer rates. Processing conditions should be considered in formulation. The ability of fiber to compete with other ingredients for water

such as wheat gluten can vary as a function of processing temperature. An important nutritional factor that bears consideration is the phytic acid content of many brans. Phytic acid is a natural component of brans that can complex with key minerals such as calcium, copper, zinc and iron. Other considerations in designing fiber ingredient specifications are freedom from microbial contamination, and their taste and/or aroma profiles. (1500)

14. Health Benefits of Probiotics For thousands of years microbial cultures have been used to ferment foods and prepare alcoholic beverages. In Genesis references are made to the preparation of fermented milk. In the past century, various micro-organisms have been tested for their ability to prevent and cure diseases in animals and humans. Micro-organisms have also been added to domestic animal feed to enhance growth. Based on these new applications, the word probiotic was used to describe beneficial micro-organisms. Later a probiotic was defined as 'a live microbial feed supplement which beneficially affects the host animal by improving its microbial balance'. In this paper a review of probiotics currently used, selection criteria for probiotics, purported health claims for probiotics and scientific evidence for these claims will be presented. One criteria which has been used to select probiotics is species compatibility. The general principle is that a probiotic isolated from an animal is less effective in another animal. However, many probiotics are of unknown origin and therefore inter-species use of probiotics is common. The other major selection criteria that have been applied for probiotics include the ability to survive transit through the gastrointestinal tract,

adherence to the intestinal epithelial cell lining, production of antimicrobial substances towards pathogens, ability to stabilize the intestinal microflora, antigenotoxic properties, a short generation time, a good shelf life in food or powdered preparations and non-pathogenic properties. In regard to the ability to survive in the gastrointestinal tract a potential probiotic's ability to survive in a low pH environment and to survive in the presence of bile has been used as a screening technique. Many probiotics currently being used have been assumed to be safe based on past history of a lack of medical problems reported for the genera of which that probiotic is a member. An example has been Lactobacillus and Bifidobacterium. However, there can be species differences in pathogenicity and this is always an issue that should be considered in the selection of probiotics. Animal feeding studies using reasonable doses can be helpful in this regard. In general, probiotics that have been selected in recent years meet at least some of the criteria listed above. In contrast microorganisms that have been used for many years in the food industry and as over-the-counter health supplements often have not met any of the experimental selection criteria listed above and hence often may not survive in the gastrointestinal tract. (2300)

15. Effect of Olive Oil on Processing and Quality Characteristics of Fermented Sausages Dry fermented sausages are meat products with a high fat content, which is visible in the sliced product. Dry sausages made with a normal recipe have fat content around 32% directly after manufacture (fresh mixture), but during the first week this value rises to about 40% as a result of drying, and after 4 weeks to about 45-50%. The granulated fat in dry fermented sausages

has important technological functions. It helps to loosen the sausage mixture and this aids the continuous release of moisture from the inner layers of the product; a process necessary for undisturbed fermentation and aromatization. Pork backfat used in fermented sausages has about 40% saturated fatty acids while cholesterol is the most important sterol present. Health organizations all over the world have promoted lowering the intake of total dietary fat, saturated fatty acids and cholesterol as a means of preventing cardiovascular heart disease since it is known that ingestion of most saturated fatty acids increases the concentration of plasma low-density lipoprotein (LDL)-cholesterol in humans, and elevated levels of plasma LDL-cholesterol are correlated with increased risk of coronary heart disease (CHD). Although polyunsaturated fatty acids decrease plasma LDLcholesterol incorporation of high levels of polyunsaturated fatty acids in the diet has been reported to promote carcinogenesis in experimental animals. Furthermore, polyunsaturated fatty acids reduce the level of plasma highdensity lipoprotein (HDL)-cholesterol, which has been shown to have an inverse relationship with the incidence of CHD. In contrast to polyunsaturated fatty acids, increasing monounsaturated fatty acids in the diet decreases the plasma LDL-cholesterol without reducing plasma HDL-cholesterol. Olive oil is the most monounsaturated vegetable oil. It contains 56.3-86.5% monounsaturated fatty acids, 8-25% saturated and 3.6-21.5% polyunsaturated fatty acids. It is also rich in tocopherols and phenolic substances which act as antioxidants. Olive oil has a high biological value attributed to its high ratio of vitamin E to polyunsaturated fatty acids contents. It has a lower ratio of saturated to monounsaturated fatty acids than any other vegetable oil and antioxidant substances at an optimum concentration. Diets high in monounsaturated fat have been associated with decreased risk of coronary heart disease.

Prevalence of heart disease is relatively low in areas of the Mediterranean region in which diets high in monounsaturated fats are consumed. In addition, it was found that increased olive oil consumption was associated with significantly reduced breast cancer risk whereas margarine intake appeared to be associated with an elevated risk of the disease. Thus the incorporation of olive oil in meat products may have a positive effect on consumer health. (2500)

16. Removal of Water The proportions of moisture in the raw materials, that is, muscle and adipose tissues, that make up dehydrated meat products, usually amount to 70-75% and 5-25% respectively. In dehydrated meats, the moisture content is only 5-15%, while for cured ham it may be about 30% for small-size products, and 3045% for larger ones. Because of the variable amounts of lipid in the comminuted meat products, it is customary to introduce a parameter which is practically independent of the extent of drying. This is the moisture content of the defatted product, abbreviated HPD: HPD= 100 x total moisture content 100-% of fat The value of this parameter is 60% for small-sized sausages and 50-55% for pieces of larger diameter. It generally lies between 55 and 70% for cured ham. The removal of moisture from the foodstuff results from two simultaneous transport processes, the transfer of heat, which occurs by convection of ambient air toward the product, and the transfer of moisture in the opposite direction.

There are several phases during the drying of a given material, depending on the speed with the removal of moisture takes place. In general, the rate of drying depends on the conditions in the chamber, and also on the intrinsic properties of the foodstuff. (1300)

17. Effect of soya milk and Bifidobacteriumfermented soya milk on plasma and liver lipids The potential role of dietary soya in the prevention and treatment of chronic diseases, in particular, heart disease and cancer, has been recognized for a long time. Soyabean protein, isoflavonoids, phospholipids, saponins, and phytate have been investigated in a search for the active component responsible for the anti-atherogenic effect of soya. Some experiments suggested that the amino acid profile of proteins and other non-protein components present in soya may be partially responsible for the hypocholesterolaemic effect. However, the mechanism and component responsible for the effect remain unclear. Many types of soya food are consumed throughout the world. A new class of soya food is being developed to reduce soya's beanlike flavour, for incorporation into human foods. Soya milk is an aqueous extract of whole soyabeans. However many people find the taste of soya milk undesirable. Soya milk contains soyabean protein and isoflavones, which are thought to have an antiatherogenic effect. The combination of soyabean protein and minor components may be important. The fermentation of soya results in compositional changes in isoflavones, phytate and saponins. Bifidobacterium breve YIT 4065, which is used as a commercial fermented milk starter in Japan, is suitable for the fermentation of soya milk. Bifidobacterium breve YIT 4065 produces lactate and acetate, which could change the

physicochemical character of soyabean protein, and cause the release of aglycones from isoflavone glucosides by Bglucosidase. Terpstra et al. (1991) showed that the hamster is a useful animal model for studying the effects of dietary proteins on lipid metabolism in the presence and absence of dietary cholesterol. Hamsters are known to have similar responses to human subjects with respect to dietary influences on blood lipids. An ethanol extract of isolated soyabean protein, which contains isoflavones, caused a more sensitive response to blood lipids in hamsters than in rats. (1600).

Section IV Texts for home reading and rendering 18. Biochemistry of the Glutamic Acid Fermentation The production of glutamic acid from glucose by microorganisms in high yields is carried out byspecies of Micrococcus, Corynebacterium, Brevibacterium, Microbacterium, Bacillus, and Arthrobacter. All of the species of the above genera which excrete glutamic acid are taxonomically similar and probably should be placed in a single genus. .Since practically all .forms of life produce this amino acid, the glutamate excreters obviously possess special characteristics which allow them to excrete large quantities of glutamate. These properties are a nutritional requirement for biotin and the lack, or very low content of, α-ketoglutarate dehydrogenase. The biotin requirement is the major controlling factor involved in the fermentation. If enough biotin is supplied for optimal growth, the organism produces lactate. Under conditions of suboptimal growth, glutamate is excreted.

Production of glutamate from glucose is not a simple reaction. The major route shown with the heavy arrows in Fig. 1 involves at least 46 enzymatic steps. This major pathway involves conversion of'glucose to phosphoenolpyruvate and pyruvate (C3) via the EMP pathway. These three-carbon compounds are then converted to ketoglutarate by reactions involved in the early part of the TCA cycle. Since these organisms lack α-ketoglutarate dehydrogenase, which ordinarily would catalyze the next step in the TCA -cycle (the conversion of α -ketoglutarate to succinate), the α-ketoglutarate is instead converted to glutamate by reductive amination. The enzyme catalyzing this conversion is the NADP-specific glutamic acid dehydrogenase. The presence of this enzyme is essential to glutamate formation. If resting cells are incubated with glucose in the absence of ammonia, α.-ketoglutarate accumulates rather than glutamate. It has been claimed that the content of glutamic acid dehydrogenase is much higher in glutamate excreters than in organisms which do not have this property; however, SHIIO et al. found Brevibacterium flavum and Escherichia coli to have, similar levels. The NADPH2 required for the action of glutamic acid dehydrogenase is supplied by the preceding isocitrate dehydrogenase reaction. Glutamic acid dehydrogenase, in turn; provides the NADP required for the isocitrate dehydrogenase step. As mentioned above, the low content of α-ketoglutarate dehydrogenase favors glutamate production. The enzyme has been reported to be missing in Brev. Flavum to be low in Brevibacterium divaricatum, and to be low. during the phase of glutamate excretion but to rise later in Bacillus megaterium. The importance of the lack of this enzyme has been demonstrated with E. coliwhich does not require biotin and is not a glutamate excreter. Even without the biotin requirement a mutant which lacks α-ketoglutarate dehydrogenase was found to excrete 2.3 g/1 of glutamate while, its parent excreted nothing.

19. Cured ham Cured ham is an uncooked pork butchery product which is first dried and then left to mature. Retention of the original anatomical structure distinguishes it from the dry sausage already described. However, it is similar to this last product, belonging to the second category of 'foodstuffs of intermediate equilibrium moisture content at the close of drying, and by the importance in manufacture of curing agents. The raw material is pork ham joints taken preferably from carcasses chilled quickly after slaughter and kept refrigerated after cutting, thus limiting microbial growth. Curing is preceded by a preparation stage, in the form of successive rubbing, either in the fresh state or after freezing, in which case penetration of salt and loss of water are accelerated. The first rubbing is done with a complex mixture consisting principally of salt, nitrates, and spices, together with sugars and water in some cases. Subsequent rubbing is usually confined to the application of salt alone, to maintain the maximum level of salt concentration. The duration of contact with the salt varies with the weight of the ham, but for commercial production about 20 days is usual. This operation takes place in the cold, usually at temperatures between + 4°C and + 1°C. During this stage the product loses around 2 to 4% of its weight in the form of water and halophilic proteins. The ensuing stage, termed 'desalting', is intended, among other things, to remove excess salt. It consists of dipping in cold running water, followed by draining for a period of 12-24 h. In industry, this phase consists of initial brushing, followed by spraying with lukewarm water, and drying at 2-5°C for 3-6 weeks. The loss of weight, at the close of this treatment, amounts to 10-12%. Next comes stoving, an operation which, though often neglected in the traditional manufacturing process, seems to be of prime importance for

flavour, and is practised systematically on a commercial scale. A temperature of 20-30°C is maintained for a week, while the relative humidity fluctuates between 65 and 85%. During this phase of treatment, degradation of proteins and fats is initiated, while the loss of weight reaches an overall figure of 16-18% of the initial weight. The final phase is drying, which lasts from 2 to 6 months and on a commercial scale is carried out at a temperature of 13-16°C and a relative humidity of 75-85%; intermittent ventilation reduces the risk of crust formation. In industry there are distinct stages, the last of which is called 'finishing'. Its duration directly determines the flavour and texture characteristics of the final product. To limit total loss of weight to 25-28% it is preceded by an operation in which the exposed muscle parts are coated with pork leaf fat or lard. (2400)

20. The treatment and use of water in brewing Brewing requires a plentiful supply of good clean water. Water accounts for approximately 95% of the total beer volume. Water, often called liquor in a brewing context, is used for: 1. Treated brewing water - brewing and processing - dilution - cleaning and CIP 2. Softened water - bottle washing - pasteurisation 3. Mains/untreated water - general cleaning e.g. floors 4. Demineralised water - boiler feed water

The volume of water required varies between breweries, but is generally about six and a half times the total volume of beer produced. Additional water is expelled as effluent during the generation of services, as water vapour from boiling and in the spent hops and grain. In order to be suitable as for use in brewing, water must be: -

Microbiologically pure (coliform bacteria are an indicator of microbial purity and should be absent from a 100ml sample). - Clear and colourless (turbidity and colour can be caused by suspended solids). - Tasteless and odourless (chlorinated water can effect beer flavour). - Neutral pH (water should be neutral pH 7, or very slightly acidic). - Free from heavy metal ions (these should be absent from brewing water. Different beers require specific mineral ions). Water composition can influence beer quality in three main areas: - Microbial contamination and beer spoilage; - Mineral composition and pH; - Organic compounds and flavour taints. The brewer must ensure he controls these factors, and most breweries will be obliged to carry out some from of water treatment. Many brewers draw their water from the municipal town supply and hence have little control over its composition, especially since many authorities draw their water form a number of

reservoirs which may lead to variations in water composition. In the EC (European Community) all water supplied from the water authorities is required to be suitable for drinking to a standard speciffed by The European Council Directive 80/778/EEC; however, this does not mean it is of ideal quality for brewing without further treatment. Some brewers may draw their water from their own wells or boreholes. The brewer then carries the responsibility to ensure the water meets the EC standards and is suitable for brewing. (1800)

21. Dietary antioxidants; nutrient and non-nutrient. The human diet contains an array of different compounds that possess antioxidant activities or have been suggested to scavenge ROS (reactive oxygen species) based on their structural properties. The most prominent representatives of dietary antioxidants are ascorbate (vitamin C), tocopherols (vitamin E), carotenoids, and flavonoids. Apart from vitamin C, each group of these antioxidants consists of a number of structurally different compounds; e.g. more than 600 different carotenoids have been identified to date and about fifty of them might occur in the human diet. In the diet, there may be synergistic effects of these various dietary compounds which are difficult to assess at present. Indeed, the diet may be considered as an orchestra where interactions between constituents may bring about effects which are not the necessary properties of the individual constituents. Vitamin C is considered to be one of the most powerful, least toxic natural antioxidants. It is water-soluble and is found in high concentrations in many tissues; human plasma contains about 60 y.mol ascorbate/1. On interaction with ROS it is oxidized to dehydro-ascorbate via the intermediate ascorbyl free

radical. Dehydro-ascorbate is recycled back to ascorbic acid by the enzyme dehydro-ascorbate reductase. Thus, dehydroascorbate is found in only very low levels compared with ascorbate. As a scavenger of ROS ascorbate has been shown to be effective against the superoxide radical anion, H2O2, the hydroxyl radical, and singlet oxygen. In aqueous solutions vitamin C also scavenges reactive nitrogen oxide species efficiently, preventing the nitrosation of target molecules. The major sources of ascorbate in the diet are fruits, especially citrus fruits, kiwi fruit, cherries and melons, and vegetables such as tomatoes, leafy greens, broccoli, cauliflower, Brussels sprouts, and cabbage; its content might exceed lOOmg ascorbate/100 g fresh weight. At low dose levels (100 mg) the bioavailability values for vitamin C from synthetic and food sources are very similar the efficacy of absorption decreases with increasing dose levels. There is evidence from studies in vitro that vitamin C is capable of regenerating tocopherol from the tocopheroxyl radical which is formed on inhibition of lipid peroxidation by vitamin E. (2300)

22. Prebiotics and synbiotics: concepts and nutritional properties The main role of diet is to provide enough nutrients to meet the requirements of a balanced diet, while giving the consumer a feeling of satisfaction and well-being. The most recent knowledge in bioscience supports the hypothesis that diet also controls and modulates various functions in the body, so as to contribute to the maintenance of a state of good health and reduce the risk of some diseases. It is such an hypothesis which is at the origin both of the concept of “functional food” and the development of a new discipline of the 'functional food science.

A” functional food” is a food which contains (in adequate proportion) one or a combination of components which functions in the body so as to have positive cellular or physiological effects' (Roberfroid, 1996). Research and development of 'functional food' is part of the science of nutrition and the benefit associated with its intake has to be in the context of the diet. The strategy for research and development of a 'functional food' requires: (1) the demonstration of an interaction with (a) function(s) in the body; (2) some understanding of the mechanism thereof; (3) the establishment of the effect in relevant biological systems; (4) the formulation of sound hypotheses; (5) the testing of these hypotheses in human nutrition studies. The concepts of prebiotics and synbiotics In the context of this paper the potential 'functional foods' to be discussed are the prebiotics and the synbiotics. A prebiotic is defined as a nondigestible food ingredient that beneficially affects the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon. It is a substance which modifies the composition of the colonic microflora in such a way that a few of the potentially healthpromoting bacteria (especially lacto-bacilli and bifidobacteria) become predominant in numbers. A synbiotic is the product in which both a probiotic and a prebiotic are combined in a single product. It is defined as a mixture of a probiotic and a prebiotic that beneficially affects the host by improving the survival and the implantation of live microbial dietary supplements in the gastrointestinal tract, by selectively stimulating the growth and/or by activating the metabolism of one or a limited number of health-promoting bacteria'. The prebiotics developed so far are the non-digestible oligosaccharides and especially the non-

digestible fructans among which chicory fructans play a major role. (2200)

23. Alkaloids Since, by definition, alkaloids are physiologically active upon animals, and many alkaloids are important drugs, the compounds are best known to the pharmacologist. Much of the voluminous literature on alkaloids is the direct or indirect result of their great economic importance. It is probable that alkaloids are less well known to most botanists than are certain compounds or classes of compounds that serve some structural or obvious functional role in the plant (for example, lignin, and plastid pigments). Consequently, a brief general discussion, including a limited treatment of the chemical affinities of the major classes of alkaloids will precede the section directly treating their sytematic significance. In this latter section no attempt is made to give a comprehensive account of alkaloid distribution or to develop any unified system of phylogenetic interpretation. Each of a number of more natural classes of alkaloids could be given such a treatment, and in fact some investigators have already done so. Certain of these latter types of studies will be described, but they have been selected mainly to provide further insight into general principles applicable to the evaluation of the systematic worth of alkaloids. In general, discussion of biosynthetic mechanisms past the point required to clarify some point of phylogenetic interpretation is beyond the scope of this book, especially in the case of the alkaloids, wherein many classes of compounds exist, each of which may be formed by almost completely independent biosynthetic routes.

The subject of alkaloid biosynthesis is rarely given comprehensive formal review, and then one is impressed with the incompleteness of knowledge and the prevalence of hypotheses supported by circumstantial evidence alone. It should be noted that numerous alkaloids show structurally a potential relationship to one or more amino acids. Consequently, it is generally regarded that alkaloid synthesis is related to amino acid synthesis. This generalization has proved helpful in seeking relationships between alkaloids otherwise difficult to interpret. Hegnauer (1958) has placed the major alkaloid types into amino acid "families" for purposes of disclosing useful systematic correlations. The arbitrary basis of such schemes should be remembered, however. The directness of the relationship of the biosynthesis of a particular alkaloid to a corresponding amino acid may vary greatly in different cases. (2000).

24. The relationship between marbling and sensory traits in beef. Although marbling of beef is an important trait in a number of beef markets, the relationship between marbling level and palatability of beef is not clearly defined. Palatability of beef can be described as a function of tenderness, juiciness and flavour and is generally measured using one, or a combination of objective and sensory measurements. The former includes shear force, compression and adhesion measurements, which all describe specific dimensions of texture. Perry et al. (2001a) showed that these objective measurements were well related to sensory tenderness, although they are by nature rather simplistic measures and do not take into account the complex interactions that occur with flavour and juiciness dimensions during the eating process.

Sensory evaluation is performed by either a trained, or consumer (i.e. untrained) taste panel. A trained taste panel is skilled in independently scoring the different dimensions of palatability, whereas scores from consumer panel are more variable and generally the correlations between the different sensory dimensions is high. These high correlations between the different sensory dimensions complicate the interpretation of the relationships between the different sensory traits and carcass traits, such as marbling. A perception common to both the meat production and food service industries is that higher marbling gives rise to more tender beef. However examination of the literature shows that the relationship between marbling and tenderness is low and variable, with some studies showing a small positive association, whilst others have failed to report any significant trend. A theory popular with the food service sector is that marbling provides an insurance against the negative effects of overcooking. The argument is that fat conducts heat at a slower rate than lean and this acts to protect and insulate the muscle fibres against the shrinkage and denaturation that occurs as meat is exposed to high cooking temperatures. Therefore highly marbled beef would be expected to be both more tender more juicy than lowly marbled product if cooked to a higher degree of doneness. This was investigated in a CRC (Cooperative Research Centre) study by Rymill et al. (1997) where steaks across a range of marbling scores were cooked to rare and well done endpoints and then sensorytested. The authors found no evidence of an interaction between marbling and doneness on taste panel tenderness and juiciness scores, which does not support the theory that high intramuscular fat levels are

beneficial to eating quality when steaks cooked to a well done end-point. They concluded that degree of doneness was considerably more important in producing tender and juicy steaks than was intramuscular fat percentage. (2000)

Section V Texts for reading and rendering in English 25. On the History of the Department of Grain Science and Industry at Kansas State University The roots of the Department of Grain Science and Industry at Kansas State University reach back to a chemistry laboratory in old Denison Hall. There in 1905, J. T. Willard, head of the Department of Chemistry, installed an experimental mill to begin evaluating the milling quality of new strains of hard winter wheat being developed for Kansas and the Great Plains. By 1910 the work had grown and culminated in the establishment of the Department of Milling Industry. Funding for the new department was solicited by the director of the Kansas Agricultural Experiment Station from millers and wheat growers throughout the state. Funds ultimately were provided by the Kansas millers, who raised nearly $2.000; the Kansas City Board of Trade. and the Kansas City millers. Total funds raised were $2,382. Goals of the department were to promote the use and improve the quality and handling of Turkey-type wheats, as well as to do research on those topics and grain storage methods. In 1913 the state legislature appropriated $7.500 for mill equipment The machinery was installed in Agriculture Hall when it was constructed in 1913 and was placed in operation in

January of 1914. The mill had a capacity of approximately 145 cwt per 24 hours. In 1937 a basic four-year course for students in milling industry was developed and the old major in flour mill engineering was dropped. Courses were added until students were permitted to specialize in milling administration, technology or chemistry. Ultimately the state legislature appropriated $10.000 for new equipment, and a number of milling companies also made donations to modernize the mill. When the remodeling was finished in 1948, a total of $80.000 had been spent on the project. At the request of the feed industry, the feed technology curriculum was added to the Department in 1951. Plans were drawn for the formula feed industry to raise $250.000 to build a structure to house a feed mill and other needed facilities The Feed Technology Building was dedicated on November 10. 1955 Final cost for the structure was $331,000. Over 275 firms contributed cash, equipment or services.

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