ALBERT

Notes: Trypsin inhibitor and lectins in raw corn-soybean blends (92/8 and 84/16 w/w, dry basis) cooked in limewater decreased with cooking time and increasing lime concentration, with total inactivation occurring, in all cases, after 30 min. These factors, determined in raw corn-soybean (92/8 and 84/16 w/w, dry basis) tortillas decreased with increasing hot plate contact time; total inactivation of both occurred only with 92/8 tortillas after 60 sec. Antinutritional factor inactivation rates were considerably higher for hot plate cooking than for limewater boiling. Soaking cooked blends in liquor after turning off the heat and allowing to cool, followed by grinding into a dough had little effect on antinutritional factors, while washing cooked blends with water resulted in some reduction of both factors. Corn-soybean tortillas prepared with normal heat treatment had no residual factors, while those prepared with minimum heat treatment had insignificantly low residual trypsin inhibitor and no lectins.〈section xml:id="abs1-2"〉〈title type="main"〉SUMMARY & CONCLUSIONSEFFECTS of processing parameters on trypsin inhibitor and lectin contents of corn-soybean tortillas prepared by lime cooking of whole raw corn-soybean mixtures may be summarized as follows.〈list xml:id="l1" style="custom"〉1Cooking time in boiling limewater and on the hot plate produces the largest reduction of both trypsin inhibitor and lectins. Due to higher temperature and higher initial blend moisture content involved, hot plate cooking exhibits higher inactivation rate than limewater boiling. Total reduction of antinutritional factors is higher when boiling in limewater, however, due to considerably longer processing time employed as compared with hot plate cooking.2Trypsin inhibitor and lectin inactivation rates on boiling in limewater appear to increase with increasing lime concentration due, probably, to additional protein denaturation by higher pH's.3Soaking in cooking liquor after boiling in limewater and turning off the heat results in relatively little reduction of trypsin inhibitor and lectins, because temperature begins to drop after the heat has been turned off.4Some trypsin inhibitor and lectins appear to be leached out into the liquor during cooking and removed by subsequent washing. This effect, however, produces relatively little reduction of both antinutritional factors.5Grinding of cooked corn-soybean mixtures into a dough involves relatively low temperatures and produces very low temperature rise; consequently, this process probably results in negligible change in trypsin inhibitor and lectins.6In all experiments performed, lectin agglutinating activity to human blood was appreciably lower and more easily destroyed by heat treatment or increasing lime concentration, than to rabbit blood.7Tortillas prepared by limewater cooking of whole raw corn-soybean mixtures by the traditional method would probably be free from trypsin inhibitor and lectins if normal heat treatment, resulting from employment of usual processing conditions (i.e., boiling in limewater for 30 min and cooking 45 sec on a hot plate, alternating sides, 15 sec each side) were applied. In this case most antinutritional factor activity would be destroyed by limewater cooking, with additional heat treatment applied on the hot plate serving as a safety factor. If, on the other hand, a heat treatment lower than normal were applied, tortillas with residual trypsin inhibitor, but no lectins, could result. Trypsin inhibitor level, however, would probably be too low to be of any significance.It can be concluded that, because of the reduction of the concentration of trypsin inhibitor and lectins, corn-soybean tortillas prepared by the method described in this paper would probably be suitable for human consumption.

Notes: A low cost powdered infant formula made from soybeans, oats and sucrose, fortified with methionine, vitamins and minerals, has been developed. A dry process for making the formula, which employs a low-cost Brady extruder, has also been developed. The resulting product is of good microbiological quality and disperses readily in water to give a milk-like suspension of satisfactory stability to settling. The essential amino acid pattern of the formula, its PER and NPU values, nitrogen balance data with infants, proximal chemical analysis, calorie distribution and low level of trypsin inhibitor indicate it to be adequate for feeding infants 3 months or older. Clinical trials with infants also showed that the formula was well accepted and tolerated, and produced adequate weight gain. Retail prices of the product, packed in cans and polyethylene bags, are appreciably lower than those of comparable cow's milk and other soya-based infant formulas available in the market. The product is currently being manufactured and sold in several parts of Mexico.

Notes: Mesquite beans (Prosopis juliflora) consisted of pericarp, hulls and kernels. With the exception of kernels, composition of beans and their fractions were protein, 10–15%; fat, 2–3%; crude fiber, 20–30%; sucrose, 21%; reducing sugars, 2–6%. Kernels contained 38% protein, 3% fat and 9% crude fiber. Bean trypsin inhibitor content was 1.4 TIU/mg. Bean protein isoelectric point was pH 5. Mesquite protein concentrate and isolate were prepared, however, by increasing solubility at the extraction pH (pH 10) with NaCl and decreasing it at the isoelectric point with (NH4)2SO4. First and second limiting amino acids for bean protein were threonine and isoleucine, respectively; the protein was high in total sulfur amino acids and tryptophan. Corrected PER was 1.4.

Notes: Cottonseed/soybean blends (50/50) were ground in an Alpine pin mill with or without previous cooking in a Brady low-cost extruder. Free gossypol decreased with increasing amount of water added prior to extrusion and number of passes through the extruder. Available lysine increased with decreasing amount of added water but was unaffected by number of passes through the extruder. Type of soybean raw material utilized had no effect on free gossypol. Blends prepared from defatted cottonseed meal, however, had lower free gossypol than those made from cottonseed kernels. A blend similar to full-fat soy flour but of lower cost was prepared from unextruded 50% defatted cotton-seed meal/50% extruded soybean flakes, without added water, and ground in the Alpine mill.

Notes: Abstract The objective of this study was to calculate, prepare and evaluate the Protein Efficiency Ratio (P.E.R.) and Net Protein Utilization (N.P.U.) of two infant formulas made with amaranth (Amaranthus cruentus). Both formulas were formulated to match a previously developed and tested soy-oats infant formula. No significant differences were found between the three formulas with respect to corrected Protein Efficiency Ratio (P.E.R.) and Net Protein Utilization (N.P.U.) values. Only the product made with the 1-R fraction of amaranth was found to have a significantly lower P.E.R. than casein.