The role of selenium has been changed over the last decade. The element that was previously considered to be toxic turned out to be present in the human body in amounts of 10–15 mg, and almost every cell of our body contains it. Selenium contributes to growth, supports healthy muscle activity, reproductive organs, reduces the toxicity of certain elements such as mercury, supports the immune system, and even delays the spread of certain viruses (influenza, Ebola, HIV). Selenium-deficient areas of Europe could be a risk for their populations. The recommended daily intake (RDA) of selenium is 55 µg/day, while WHO and FAO have set up the daily tolerable dose at 400 µg/day. We must count with the harmful effects of selenium overdose, but it is almost impossible to introduce this amount into our body solely with food. Our selenium sources can be refilled with food supplements or selenium-enriched functional foods. In the review article, we report about the role of selenium in the environment, selenium-enriched plants, selenium-enriched yeast, the role of selenium in animal feed and in the human body, the opportunities of selenium restoration, selenium-enriched animal products, and the selenium content of milk.
We have developed a new procedure for reducing soy trypsin inhibitor activity by means of heat treatment combined with chemical methods, through which soy trypsin inhibitor activity decreases to the tenth or twentieth part of the original value. We determined the optimal concentration of the applied chemicals (hydrogen-peroxide, ammonium-hydroxide) as well as the optimal temperature and duration of the treatment. The chemical procedure combined with heat treatment results in lower energy consumption as compared to the original heat treatment methods.
The research subject is the elaboration of a method and procedure for processing feather from poultry slaughterhouses and using it as antioxidant as well as for satisfying the sulphurous amino acid needs of ruminants. We investigated the level of digestion of the meal feather obtained with our technology, its antioxidant effect and role in the rumen fermentation of the ruminants. Making use of the digested feather meal’s antioxidant effect and amino acid composition, we make a suggestion for the preparation to be used as antioxidant and for the satisfaction of the sulphurous amino acid needs of ruminants. By adopting this procedure, the valueless feather can be transformed into a useful feed supplement (natural antioxidant, sulphur source) that can bring about significant economic growth. Pre-trials have been performed successfully, and in what follows we’ll need to prove through field trials and pilot-scale experiments that feather meal can be produced and utilized economically as antioxidant in monogastric animals and as a sulphur source in the studying of ruminants.
During our research, we added extracted soya bean meal, egg-white powder, gluten, wheat sourdough, and bamboo fibre to wheat flour in order to increase the quantity of the essential amino acid and the biological value of the wheat protein, producing such a functional, health-protecting, health-preservative food product which is suitable to satisfy the essential amino acid requirements of humans, assuming normal nutrition. Furthermore, we could produce such a food, which, on the one hand, was suitable to confine or prevent the essential amino acid’s malnutrition symptoms, while, on the other hand, when applied alone, to meet the consumers’ needs. During our work, we determined the protein content and amino acid composition of the wheat flour, of the additives used in bread baking, and in the bread both baked with supplementation (Update1 bread) and without supplementation (normal bread), as well as the quantity of the Maillard reaction products (hydroxymethylfurfural). We calculated the biological value of the protein of different breads and evaluated the sensory characteristics of the produced functional food and the fortified bread, supplemented with high essential-amino-acid-containing additives.
Following a presentation of humans’ water-soluble vitamin requirements, the authors will discuss in detail the role these vitamins play in human organism and outline those major biochemical processes that are negatively affected in the body in case of vitamin deficiency. They point out that in the elderly population of developed countries cases of water-soluble vitamin deficiency are extremely rare and they are due to the lack of dietary vitamin, but mostly to the vitamin being released from its bindings, the difficulty of free vitamin absorption, gastrointestinal problems, medication, and often alcoholism. Among water-soluble vitamins, B12 is the only one with a sufficient storage level in the body, capable of preventing deficiency symptoms for a long period of time in cases of vitamin-deficient nutrition. Each type of vitamin is dealt with separately in discussing the beneficial outcomes of their overconsumption regarding health, while the authors of the article also present cases with contradictory results. Daily requirements are set forth for every water-soluble vitamin and information is provided on the types of nutrients that help us to the water-soluble vitamins essential for the organism.
Following a discussion on the daily energy and protein requirements of elderly people, the authors will go on to talk about vitamin needs and the role of the four fat-soluble vitamins (A, D, E, and K). They point out that vitamin requirements in old age do not essentially differ from adult people’s, but they must take account of the fact that the body’s vitamin stores might get filled up, which may reduce vitamin needs, on the one part, but the altered physiological processes may increase them, on the other. Regarding the case of fat-soluble vitamins, reduced fat absorption, decreased vitamin storage capacity of the liver, reduced dietary intake, partial deficiency of digestive enzymes, and absorption disorders in the intestines may all lead to vitamin deficiencies. Problems may also arise due to multiple vitamin overdose developed either as a consequence of overconsumption of vitamin tablets or because the body’s vitamin stores are constantly filled up to maximum capacity. Positive and negative changes resulting from the consumption of several times the daily dose recommendations are covered as well. The authors show that A, D, E, or K vitamin deficiency occurs very rarely in the case of a normal diet; however, great care must be taken in order to meet vitamin D and, simultaneously, calcium requirements so that to avoid osteoporosis and an increased risk of bone fractures in elderly people. The paper discusses the fat-soluble vitamin needs of the elderly and, where necessary, specifies the requirements for men and women separately, while also touching upon those foodstuffs and methods that can contribute to the optimal satisfaction of the elderly people’s vitamin needs.
We have developed methods for the production of protected methionine and protected lysine, making use of the reaction between citric acid and malic acid as well as methionine and lysine, on the one hand, and of the interaction between swollen bentonite and the two amino acids, on the other hand. Our in vivo and in vitro experiments have demonstrated that one part of the amino acids transformed during the reaction, while another part bound on the bentonite’s surface to a significant degree. Assisted by the reaction between hydroxycarboxylic acids and amino acids, we achieved a protection of about 75% for methionine and 60% for lysine, that is, 25% of the methionine and 40% of the lysine appeared in the free amino acid fraction. The swollen bentonite bound 75% of the added methionine and 60% of the added lysine. Our chemical analyses have demonstrated that through the time–temperature combinations applied by us the methionine and lysine do not undergo significant degradation and can be fully released from the protected form. Further, our in vitro experiments using rumen fluid from fistulated cattle showed that during the average retention time of the fodder in the rumen the protected amino acids will resist microbial enzymes and maintain their protected status during their presence in the rumen.
Prebiotics are such indigestible food ingredients that enter the colon and serve as nutrient for bifidobacteria and lactobacilli. Since fibres and oligosaccharides are the typical prebiotics, we produced prebiotics in our experiments with the reaction of lactose and malic acid as well as citric acid, where these reactions made use of an appropriate concentration of these substances, had an adequate duration, and were carried out under optimal temperature conditions. We determined the optimal parameters of the reaction, measured the loss of the starting materials as well as the increase in concentration of the end-product, and analysed the total sugar content of the hydrolysed prebiotics after hydrolysis by hydrochloric acid. In vitro experiments were performed to demonstrate our end-product’s resistance to carbohydrate-degrading enzymes, which is a fundamental requirement for a prebiotic so that upon reaching the colon it can serve as nutrient for the probiotic bacteria found there.
In the Medical and Health Centre of the University of Debrecen, we examined the changes in the free amino acid content of the blood serum of control and experimental individuals after consumption of 2,000 mg of lysine-laden biscuits. We baked the biscuits at 130 °C, during which the greater part (70–75%) of the lysine was not converted into Maillard reaction products. After 30–60 minutes of consumption of the biscuits, the free lysine content of the blood serum increased significantly in the experimental and control group with 41–46%, and even after three hours of consumption the level was 20% higher than in the initial concentration. The free arginine content of the blood serum did not change after the consumption of control and lysine biscuits neither in the control nor in the experimental group. Therefore, the free lysine/free arginine ratio of the individuals consuming lysine increased significantly compared to the initial and the control group’s value. The antioxidant level of the blood serum in the control group remained unchanged after the consumption of the control biscuit, while in the case of the experimental individuals who consumed lysine-fortified biscuits it increased by 40–45% compared to the initial level. Summing up: After consumption of the biscuits with 2,000 mg of free lysine, the concentration of free lysine in the blood serum, its free lysine/free arginine ratio and antioxidant level increased significantly. Our researches have clearly demonstrated that the active substances of the biscuit got into the blood serum, so the investigation of the active substance and the evaluation of the physiological effects are definitely recommended in the long run.
In the course of the research, we determined selenium and dry matter content of 35 wheat grass and 35 wheat seed samples. The selenium content of the preparation plant probes was measured by spectrofluorimetric determination (λexcitation = 380 nm, λemission = 519 nm) of the resulted piazselenol complex. It was established that between the selenium content of the wheat grass and wheat seed the correlation coefficient was 0.36 at p = 0.05 level, which indicates a medium-close correlation. Similarly, there was a medium-close correlation between the selenium content of the wheat grass calculated on dry-matter basis and total selenium content of the wheat, with a correlation coefficient of 0.40 at p = 0.02 level. Afterwards, beside the selenium content, we measured the selenomethionine content by ion-exchange chromatography and highperformance liquid chromatography, and the organic selenium content was calculated. A very close correlation was established between the total selenium, selenomethionine and calculated organic selenium content of wheat (the correlation coefficients were between 0.92 and 0.99 at p = 0.01 level). The correlation between the selenomethionine content of wheat grass and wheat seed was very weak (r = 0.23).