Inactivation of Trypsin Inhibitors in Whole and Cracked Soybeans with Sodium Metabisulfite
نویسندگان
چکیده
Sodium metabisulfite (Na2S20S) was used to inactivate trypsin inhibitors in whole and cracked soybeans. Soybeans (400 g) steeped with 1600 ml aqueous O.IM Na2S20S at 30°C and 65°C for 2and 3-h were dehulled, dried, flaked and then defatted with either 6 batch extractions of hexane at ambient temperature or with supercritical CO2 for 15 min at 12,000 PSI and 84°C. The 2-h steep treatment at 65°C inactivated >94% trypsin inhibitor with about 60% ofthe original nitrogen solubility while the 3-h steep treatment produced greater trypsin inhibitor inactivation (i. e. >97% inactivation) with decreased nitrogen solubility of 41-50%. Less decrease in nitrogen solubility was observed for all bean samples steeped in Na2S202 at 65°C when compared with respective heat-treated controls. Gel electrophoresis patterns ofprotein extracts on 17-27% gradient gels before and after Na2S20streatment showed disappearance of both Kunitz and Bowman-Birk inhibitors. The processed soybean flakes, after milling, retained from 94 to 755 ppm residual sulfite. Supercritical CO2 extraction did not prove advantageous over hexane extraction for diminishing residual sulfite. This simple soybean steep treatment may be of commercial interest to prepare soy flour with low trypsin inhibitor activity and good protein solubility.
منابع مشابه
Effects of heating time and sodium metabisulfite on the nutritional value of full-fat soybeans for chicks.
Two 21-d trials were conducted to evaluate the effect of heating time and sodium metabisulfite (SMBS) on the nutritional value of full-fat soybeans for chicks. In Trial 1, four pen-replicates of eight chicks each were fed corn-based diets (19% CP; 3,167 kcal of ME/kg) containing either 44% CP soybean meal or full-fat soybeans. The soybeans either were unheated or were autoclaved at 121 degrees ...
متن کاملThe inactivation of native enzymes by a neutral proteinase from rat intestinal muscle.
1. The solubilization and partial purification of a proteinase from the intestinal smooth muscle of rats fed on protein-free diets are described. 2. It has a mol.wt. of about 33000 and it is stable over a narrow pH range. 3. From its susceptibility to known modifers of proteolytic enzymes, it appears to be a serine proteinase of a trypsin-like nature. Active-site titration with soya-bean trypsi...
متن کاملThe Effect of TiO2-Nanoparticle on the Activity and Stability of Trypsin in Aqueous Medium
Trypsin (E.C.3.4.21.4) is a serine protease commonly used in proteomics for digestion of proteins. In the present study, the effect of nano-TiO2 on the conformation and catalytic activity of trypsin were studied. The thermal denaturation of trypsin has been investigated in the presence and absence of nano-TiO2 over the temperature range (293-373 K) at pH 3.0 and 7.25, using temperature scanning...
متن کاملHeat inactivation of trypsin inhibitor, lipoxygenase and urease in soybeans: effect of acid and base additives.
متن کامل
Isolation and Characterization of Trypsin Inhibitors (Kunitz Soybean Trypsin Inhibitor, Bowman-birk Inhibitor) in Soybean
Soybean (Glycine max (L.) Merr.) has emerged as one of the most economical and nutritious foods. Kunitz Soybean Trypsin Inhibitor (KSTI) and Bowman -Birk Inhibitor (BBI) are the two major trypsin inhibitors in soybeans. The ingested soybean trypsin inhibitors cause growth depression as demonstrated in different animal species and human. The main part of the present study was devoted to isolatio...
متن کامل