Hydrolyzed and autolyzed vegetable proteins as functional food ingredients

Hydrolyzed vegetable or plant protein (H.V.P. or H.P.P.) can be defined as mixtures containing amino acids and frequently other substances such as salt and peptides, obtained by hydrolysis of vegetable proteins. On an industrial scale two types of hydrolytic processes are applied: acid and enzymic hydrolysis. HVP estimated sales in the western world are at least $100 million. Most HVPs are produced for internal use by soup manufacturers, for use as vital meaty or savory flavoring ingredients in bouillons, soups, sauces, processed meat, fish and poultry products and snacks. Other HVPs are more ready-made products, or have obtained additional meat flavor value by careful blending and/or by processes based on Maillard-type reactions. Of substantially less importance is the use of HVP as whipping, foaming or areating agent, as nutritional ingredients or as bread or baking improver. Most of the HVPs used for these purposes are only partially hydrolyzed by enzymes or by alkaline treatment. The legal status of HVP, food ingredient or food additive, and its safety was discussed recently at various locations. So far these discussions have resulted in the tentative conclusions that HVPs are food ingredients which need standardization, and which, at their presently used levels, can be considered as being GRAS.     

Cholesterol oxides in Swedish food and food ingredients: Lard and bacon

Lard samples, manufactured from adipose tissue, were found to contain traces and/or quantifiable concentrations of certain cholesterol oxides, viz., 5α-, 6α-epoxycholestanol, 7-ketocholesterol, 7α-hydroxycholesterol, 20α-hydroxycholesterol and 25-hydroxycholesterol at the detection limit 0.1 ppm. The influence of steam refining and chemical refining on the cholesterol oxide levels in a few of the crude lard samples was investigated. The analyses showed that these processes had no appreciable effect on the concentrations of cholesterol oxides, compared with the controls. Analysis of cold-stored consumer packages of lard (2-mo old up to 18-mo old samples) indicated that there were no differences in the pattern of cholesterol oxides. On the other hand, storage of refined superior and regular grade lard samples at 50°C for up to 18 days caused only a slight increase in the levels of the isomeric 5,6-epoxycholestanols. Raw bacon, bacon fried at 170°C for 10 and 20 min and bacon dripping were analyzed. The analyses showed that quantifiable levels of 5α-,6α-epoxycholestanol, C-7 oxidation derivatives of cholesterol and 25-hydroxycholesterol could be detected only in the fried rind. A substantial amount (about 0.5 ppm) of a cholesterol metabolite was detected in the lard samples. Its identification as 7α-hydroxycholest-4-en-3-one was based on the comparison of RRT value and mass spectral information, as TMS-ether, to that of synthetic 7α-hydroxycholest-4-en-3-one.     

Baked product development based fermented legumes and cereals for schoolchildren snack

The objective of this work was to develop three foodstuffs based on mixes of wheat and fermented and non-fermented legumes, for the purpose of contributing with a healthy alternative for school snacks. To this aim, refined wheat flour was partially substituted with whole legume flours for the preparation of cakes, brownies and cookies, foodstuffs traditionally consumed by school age children. Cakes were formulated substituting 20% of wheat flour with Phaseolus vulgaris flour, brownies with 30% of Cajanus cajan flour and cookies with 30% of Vigna sinensis flour, using fermented and non-fermented legumes in the three products. When these products were subjected to sensorial evaluation through a test of degree of acceptability and using a hedonic scale of 7 points, values higher than 5 in the attributes taste, color and overall appraisal were found for all the products. In addition, the preference was measured with a group of 90 school children, corroborating the results obtained at laboratory level. Chemical characterization showed protein contents between 12 and 13% for the cake, 10 and 11% for the brownies and 10% for the cookies and protein digestibilities in vitro of 91%, 87% and 93%, respectively. The calorie supply, calculated per portion was of 199 kcal, 246 kcal and 237 kcal, for cakes, brownies and cookies, respectively. It was concluded that it is technically possible to incorporate fermented and non-fermented Phaseolus vulgaris, Vigna sinensis and Cajanus cajan, to highly consumed products such as cakes, brownies and cookies with a higher nutritional content and well-accepted by school-age children.     

Processing of leaf proteins into food ingredients

Many process alternatives are possible. Most of them are currently being investigated by laboratory or pilot tests. The successful future of some of these processes is certainly connected to the quality of the end product vs. market requirements and consumer acceptability. The status of development of the processes does not allow any economic forecast on profitability, but it is reasonable to think that the simplest techniques to produce acceptable leaf protein isolate and sufficient control on processing conditions could be profitable. These processes need further technological development and the end product market needs to be investigated further, but leaf proteins could be an alternative and complementary source of proteins for food ingredients in the predictable future.     

Review: functional foods and ingredients derived from milk

The objective of this paper is to review the main research works related to functional foods and ingredients derived from milk. Research in functional foods has increased during last twelve years with the intention of increasing life expectancy and improving human health conditions. Probiotics, prebiotics, bioactive peptides or proteins, dietetic fibers and fatty acids, as well as the addition of fitochemical compounds in dairy products and a record of some allergic compounds are also discussed. The demand of this kind of products is increasing due to intense advertising campaigns posted in many countries. Basically, these campaigns promise better health and/or the prevention of certain illnesses. Milk contains diverse constituents with physiological functionality, which might change the traditional view point that we have about drugs. The topic of functional foods in general, and specifically that from milk and dairy products, has still not been completely exploited, and in the future it will be found that the best work has not been carried out in this area.     

Impact of ultrasound on oil yield and content of functional food ingredients at the oil extraction from sunflower

In this study, the effect of ultrasound-assisted extraction (UAE) on oil yield and content of functional food ingredients of hulled and non-hulled sunflower is discussed and compared with conventional extraction methods. The optimum extraction parameters for UAE were as follows: n-hexane as extracting solvent, average particle size 250 ± 12 µm, extraction time 2 h, solid-to-solvent ratio 1:12, ultrasound frequency 24 kHz and temperature 50°C. Furthermore, the chromatograph showed that sunflower oil extracted by the UAE was rich in α-Linolenic acid (ω-3). In addition, a marginal reduction in peroxide values and tocopherols were determined.     

Cholesterol oxides in swedish foods and food ingredients: Butter and cheese

Fresh butter manufactured by batch or continuous technologies in Sweden contained only traces of 7-ketocholesterol at the detection limit (0.1 ppm in the lipids) and no detectable levels of other common cholesterol oxides. Storage at 4°C for up to four mo caused an increase in the levels of the isomeric 5,6-epoxycholestanols, the epimeric 7-hydroxycholesterols, 20α-hydroxycholesterol and 7-ketocholesterol as revealed by Lipidex chromatography, TEAP-Lipidex chromatography and GLC. Heating of butter for 10 min at the temperature interval 150–200°C under conditions similar to that in shallow-pan kitchen frying caused a gradual increase in the total amount of cholesterol oxides from 0 to 2.5 ppm, while at 200°C the total amount of cholesterol oxides was 1.6 ppm. Butter heated five min at 200°C also had less cholesterol oxides than that heated at 190°C for 10 min. Industrially manufactured butter oil and cream oil contained only low levels of some of the cholesterol oxides. Further, three types of processed cheese (soft-melted, hard-melted and grated cheese) were investigated. The soft-melted and the hard-melted cheese types contained only traces of some of the oxides, while the grated cheese samples had 0.5–2.2 ppm of the total cholesterol oxides in the lipids.     

Electrochemical removal of sodium ion from fermented food composts

Fermented food composts, to be recycled into fertilizer and animal feed, require sodium chloride concentrations to be less than 1 wt% due to several toxicities. Electrochemical methods are used to remove sodium ions from fermented food composts. By washing the compost with tap water (with no electric current applied), 48% of the initial sodium ion is removed. With an electric current density of 3 mA/cm² (the distance between the electrodes is 16 cm), the removal efficiency increases to 96% for a 36 h operation. Major factors influencing the efficiency are the treatment time and the electric current density. Removal efficiency increases with energy demand to yield 96% removal at 60 Kwh/m². Due to the difference in relative ionic mobility, less than 9% of calcium is removed, during the same operation time, which supports the feasibility of this method.     

Glutamine synthetase in legumes: recent advances in enzyme structure and functional genomics

Glutamine synthetase (GS) is the key enzyme involved in the assimilation of ammonia derived either from nitrate reduction, N(2) fixation, photorespiration or asparagine breakdown. A small gene family is encoding for different cytosolic (GS1) or plastidic (GS2) isoforms in legumes. We summarize here the recent advances carried out concerning the quaternary structure of GS, as well as the functional relationship existing between GS2 and processes such as nodulation, photorespiration and water stress, in this latter case by means of proline production. Functional genomic analysis using GS2-minus mutant reveals the key role of GS2 in the metabolic control of the plants and, more particularly, in carbon metabolism.     

Statistical modeling of electrochemical removal of sodium in fermented food composts

Electrochemical removal of sodium ion from fermented food composts was analyzed and statistically modeled by response surface methodology (RSM). Empirical models were developed to describe relationships between the operating variables (operation time, current density and water contents) and three responses (removal efficiency, energy expenditure and energy efficiency). Statistical analysis indicated that operation time and current density have significant effect on all responses. Good agreement between predicted and measured values confirmed the usefulness of the model. The models were verified by additional experimental at optimum conditions.     

Significance for humans of biologically active factors in soybeans and other food legumes

Among the many biologically active factors present in the soybean, only protease inhibitors (PI) have been shown to exert significant adverse effects on animals consuming diets containing soybean protein. Evidence is presented to suggest that (a) PI are only partially responsible for the poor nutritive value of inadequately processed soybeans, (b) low levels of PI are relatively harmless to animals, (c) human trypsin is only weakly inhibited by PI, and (d) the human pancreas is probably insensitive to the hypertrophic effects of PI. Parelleling the wide spread distribution of PI in the plant kingdom are the so called phytohemagglutinins or lectins. Unlike the lectin present in soybeans which appears to have only a marginal effect on the nutritional quality of the protein, the lectin of the common bean (Phaseolus vulgaris) is quite toxic. Moreover, the major storage protein of such beans is quite resistant to digestion unless denatured by heat, thus emphasizing the importance of adequate processing of those legumes when used in the human diet. Although goiter-inducing compounds are present in most cruciferous plants and cyanide-producing substances may be found in cassava and lima beans, traditional methods of preparation and present technology have served to minimize any harmful effects that may accompany the ingestion of these foods by man. Brief mention will also be made of two human diseases, lathyrism and favism, associated with the consumption ofLathyrus sativus andVicia faba, respectively, their causative agents and mechanism of action. Although there are numerous examples of so called toxic constituents in legumes, they nevertheless have provided a valuable source of protein to man over the centuries. This can be attributed, in part, to the fact that man has learned how to detoxify them by suitable preparative measures. The varied nature of our diet also minimizes the contribution of a toxicant from any one foodstuff. Nevertheless, there is the ever present possibility that the prolonged consumption of a particular legume that may be improperly processed could bring to the surface toxic effects that otherwise would not be apparent. As the shortage of protein becomes more acute, it is not unlikely that much of the population of the world will be faced, in the future, with a more limited selection of protein-foods, most of which will be of plant origin and, hence, potential carriers of toxic constituents. The food scientist should at least be cognizant of such a possibility and be prepared to apply his knowledge and skill to meeting this challenge.     

Vegetable proteins in cooked and/or fermented sausages

Man is the only animal cooking meat for food. Various arts and degrees of heat treatment were devised by the early egyptians, Greeks and Romans; this was often combined with a surprisingly high degree of sophisticated fermentation. From initial meat searing in the Iron Age to modern barbecue pits, electronic conveyers, rotomats, the introduction of steam and controlled smoking, development of curing salts, and the controlled production of meat itself, man created new meat processing technology designed to improve flavor, texture, shelflife, availability, acceptability and economy, thus satisfying the crucial demands of both the consumer and processor. During this time man also discovered the disadvantage of heat, namely the inevitable loss of volume, changes in texture, color and palatability. At the same time, he started using various tubers, cereals and salts to minimize cooking losses. These functional comminuted meat product ingredients, today known as binders and fillers, have traditionally been locally available. They include potatoes, cereals, milk derivatives, hydrocolloids and vegetable proteins. It is estimated that 17,000 tons of various soy proteins were used in 1977 in Europe alone in heat-treated and fermented meat products. Since sausages, fermented and hard salamis and similar ready-to-eat comminuted meat products are an important segment of European convenience meat consumption, this paper concentrates on the technological, nutritional and economical impacts of soy proteins on these products. While in heat-treated meats bacteriological growth is not desired, it is a regulation factor in the production of fermented sausages. In both types of products, soy proteins in their present form as isolates, concentrates, textured, various grits and flours, as well as spun or structured, play an important role in providing the consumer with appealing, nutritional products at acceptable prices. Examples of applications of soy proteins are discussed.