[Intestinal alterations and reduction of growth in prepuberal rats fed with soybean]. / Alteraciones intestinales y disminución del crecimiento en ratas prepúberes alimentadas con soja.

Weanling rats from the inbred lines alpha and beta were fed with a soybean-cereal mixture used for human consumption (AN). A group fed with laboratory rat chow was used as reference (AC). Growth and other nutritional parameters as well as intestinal morphohystometry were evaluated from 22 to 44 days of age. Growth rate and final weight were greater with AC in both lines of rats. The greater initial food conversion efficiency of AN diet, compared to AC, decreased rapidly with the progression of age, particularly in the beta strain. Nitrogen (N) and lipid fecal contents were significantly larger for AN in both lines. Apparent nitrogen digestibility, expressed as the difference between N intake and fecal N with respect to N intake was AC < AN (p < 0.01) for line alpha and AC > AN (p < 0.01) for line beta. The weight and the mucosal total width of the small intestine were AC > AN in both lines. AN produced a significant decrease of villi goblet cells in both strains (p < 0.005). Cecum weight was AC > AN (p < 0.01) for the beta strain. These results alert about uncontrolled consumption of soybean products without adequate inhibition of antinutritional factors, a potential risk for growing animal populations.

[Ureasic activity in soy products. Proposal of a new method]. / Actividad ureásica en productos de soja. Propuesta de un nuevo método.

The evaluation of residual ureasic activity in soy products is usually employed as an indicator of the efficiency of the inhibition treatments. The purpose of this study is to compare the AACC method (22-90), based on differences of pH, with an assay where ureasic activity is measured by its hydrolytic action on urea and quantification of the ammonium produced with Berthelot reaction. Twenty different samples of soy bean flour with and without thermal inactivation treatments were assessed with the two methods. The new method has a good correlation with that of the AACC--r = 0.9416 (p < 0.0001). It also presents a better specificity because it measures the concentration of the reaction product and shows a more amplified answer than the increase of pH.

[Chemical and nutritional assessment of a soybean and cereal mixture for adults]. / Evaluación química y nutricional de un alimento para adultos a base de soja y cereales.

Legume seeds and fibre rich plant foods usually improve aspects of human diabetes control as they are potential sources of "delayed release" carbohydrates. A regional bakery mixture of soybean and cereals, interesting for its palatability and high content in non starch polysaccharides was chemically and nutritionally evaluated. Comparisons were made with the usual commercial laboratory chow and with a cafeteria mixture. Each one of the three diets was offered ad libitum to adult rats of line IIMb/Fm beta (beta), affected by obesity, hypertriglyceridemia and glucose intolerance or diabetes. Treatments lasted three months and were performed on two groups of male rats: (a) From 100 days old growing significantly. (b) From 200 days old. Meals had similar carbohydrate and calorie contents but acid followed by enzymatica hydrolysis was required to free monosaccharides from the soybean mixture. Cafeteria mixture lacked in fibre, was rich in saturated fats and sodium, and it caused hyperphagia. Each group of rats showed similar food intakes in both ages although weight gain was significantly higher in the younger animals. In the latter, values of glycemic response showed no difference between diets. Cafeteria mixture caused significant hyperglycemia to the elder rats, while the soybean bakery mixture produced a remarkably lower glycemic response; in one case it was even lower than the one produced by the commercial chow. Differential response showed more clearly with age. The results of the feces analysis demonstrated an increased proportion of fecal water for the bakery mixture group, probably due to the amount of undigestible fibre, inducing beneficial effects on large bowel functionality.

Actividad ureásica en productos de soja. Propuesta de un nuevo método / Ureasic activity in soy products. Proposal of a new method

The evaluation of residual ureasic activity in soy products is usually employed as an indicator of the efficiency of the inhibition treatments. The purpose of this study is to compare the AACC method (22-90), based on differences of pH, with an assay where ureasic activity is measured by its hydrolytic action on urea and quantification of the ammonium produced with Berthelot reaction. Twenty different samples of soy bean flour with and without thermal inactivation treatments were assessed with the two methods. The new method has a good correlation with that of the AACC--r = 0.9416 (p < 0.0001). It also presents a better specificity because it measures the concentration of the reaction product and shows a more amplified answer than the increase of pH.