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The survival in the rat small intestine of soybean agglutinin or Kunitz or Bowman-Birk trypsin inhibitors was studied by SDS-and native polyacrylamide gel electrophoresis, transblotting, trypsin inhibitor activity assays, and immunochemical determinations. As the inhibitors were bound in enzyme complexes in the small intestine, functional assays were unsuitable. However, as free and bound inhibitors reacted similarly with their antibodies, survival could be assayed by immunoblotting and ELISA. In addition to the mucosa-bound agglutinin, 8.6% of the original dose was free in the gut lumen and this, by moving further down in the small intestine, could have extended the wasteful gut growth from proximal to distal parts. Although only 4.8% of the Bowman-Birk inhibitor survived, most (76%) of the Kunitz inhibitor remained immunochemically intact. Accordingly, stimulation of pancreatic growth and enzyme secretion by the inhibitors, particularly the Kunitz, may have contributed to the total antinutritive effect of soybean.

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SummaryThe biologically active amines agmatine, cadaverine, histamine, phenethylamine, putrescine, spermidine, and tyramine have been determined in different varieties of grape, aszu grape, wine and aszu wine from the Tokaj region of Hungary. Ion pairs formed between the amines and octanesulphonic acid were separated by liquid chromatography on a #Bondapak C18 reversed-phase column, and spectrofluorimetric detection was performed after post-column derivatization with o-phthalaldehyde and 2-mercaptoethanol. The method was linear for the amines between 0.1 and 10 mg L -1, and for spermidine between 1 and 30 mg L 1. Comparison of the results revealed that the qualitative and quantitative content of biologically active amines was mostly determined by the vintage of the wine and the technology used for wine-making. The biogenic amine content of Tokaj wines is well below suggested limits for any of the amines, showing that the winemaking technology of the Tokaj region is of high quality. The levels of biologically active amines (identified and quantified by HPLC) in grapes, wines and aszu wines can provide useful information about the weather, growth of Botrytis cinerea in Tokaj, and aspects of the methods used for wine-making.

Biogenic amines in grapes, aszu-grapes, wines, and aszu-wines of the Tokaj region of Hungary were separated, identified, and quantified by HPLC. The biogenic amine content of the Tokaj wines was well below the suggested limits for any of the biogenic amines. Histamine contents were especially low in all the samples investigated. The composition and concentration of the biogenic amines (polyamines) in the grape berries were altered remarkably by the Botrytis cinerea, and this resulted in a great change of the amine concentration in the aszu-wines compared to the wines. The composition and concentration of biogenic amines might provide useful information on the vintage and can support the authentication of the Tokaj aszu-wines.

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~A diet-switching experiment, which aimed to improve the utilization of soyabean whey was carried out for 61d with young rats. Feeding was arranged in such a way that after a few days on the soyabean diet, the rats were switched to a high-quality lactalbumin diet for a short period, after whicb the cycle was repeated several times. The weights of the rats at the end of the soyabean phases were significantly less than those of animals pair-fed on a high-quality diet throughout. However, the test group regained the weight loss after switching to the lactalbumin diet. After three cycles there were no significant differences between the weights of the test rats fed on a poor soyabean diet for over a third of the experiment and those fed on the lactalbumin diet throughout. Feed conversion was always significantly higher with test rats in the lactalbumin period than with continually pairfed controls. Similarly, faecal N losses were significantly higher for test rats in the soyabean phase, but these differences disappeared after switching to the lactalbumin diet. At the end of the experiment there were no significant differences in body protein or lipids between the groups although the pancreas was signi6cantly heavier while the liver was lighter in soyabean-fed rats. The high destruction of trypsin inhibitors in the gut suggests that they probably had little effect on protein digestion in the gut. In contrast, as selective depletion of the agglutinin from soyabean whey removed the nutritional benefit in the lactalbumin part of the cycle, the improved feed conversion in this period must have been the result mainly of the survival and functionality of soyabean agglutinin and the benefits due to the hyperplastic growth and faster renewal of the gut surface it induced. As processing is unnecessary, this novel method is cheap and can be easily adapted for the use of soyabean whey, regarded as a waste product. Diet-switching: Feed conversion efficiency: Soyabean whey: AgglutininThe use of soyabean in human food is increasing and soyabean proteins often supply the bulk of dietary protein in animal nutrition. Unfortunately, as soyabeans contain a number of antinutrients, mainly a lectin (or agglutinin) and two trypsin inhibitors, the efficiency of nutritional utilization of diets containing soyabean products is below that expected from chemical composition (Gupta, 1987). This is particularly so when these are fed for long periods (Rackis ef al. 1986) and in the case of soyabean whey, which contains most of the antinutrients (Grant ef al. 1986). It is a commonly-held view that soyabean products could be more extensively used in both human and animal diets if their antinutritional effects were reduced.The antinutritive activity of lectins stems from their ability to recognize and specifically bind to carbohydrate side-chains of membrane glycans of brush-border epithelial cells. As some of these are receptors of growth andor metabolic factors, .Unlike lectins, trypsin inhibitors do not interact with the brush border of the smal...

The effects of natural fermentation upon the lectin in the seeds of Lens culinaris cultivar Magda 20 were investigated. Suspensions of lentil flour were allowed to ferment naturally at different lentil flour concentrations (79, 150 and 221 g l -1 ) and temperatures (28, 35 and 42°C). During fermentation, samples were taken at daily intervals (0, 24, 48, 72, and 96 h) and lentil lectin activity was measured by haemagglutination test. With the progress of fermentation there was a rapid decline in haemagglutination activity in all the batches. The largest decrease occurred between 0 h and 24 h of fermentation in all the conditions. The lectin concentration showed the maximum reduction at 72 and 96 h, under the fermentation conditions of 79 g l -1 and 42°C, when the initial lectin content measured by ELISA was reduced by 98 and 97.8%, respectively. The changes in lentil lectin were also followed by SDS-polyacrylamide gel electrophoresis and immunoblotting. The results confirmed those obtained by ELISA and indicated that the lectin almost disappeared after 72 h of natural fermentation under the optimum conditions of flour concentration and temperature.