Mara Lúcia Luiz Ribeiro

Efeito da germinação de soja CV. BR-13 e Paraná sobre ácido fítico, fósforo total e inibidores de tripsina

The aim of this work was to evaluate the effect of germination on the antinutritional constituents of soybean, phytic acid, total P and trypsin inhibitors that interfere with the utilization of proteins and other substances. The decrease of the nutrient utilization results in growth inhibition, hypoglycemia or damage to animal tissues. Seeds of soybean (Glycine max (L.) Merrill) cultivars BR-13 and Parana were incubated in germination chamber at 25°C and 100% of humidity, from 0 to 72 hours, and samples were collected in intervals of six hours. The Parana cultivar presented higher amount of phytic acid, total phosphorus and trypsin inhibitors, than the BR-13 cultivar. The analysis of variance and comparison among the means indicated that, in 72 hours of germination, there was a significant increase (p<0.05) on the amount of total phosphorus (8.5% and 3.6% for BR-13 and Parana cultivars, respectively) and on the level of trypsin inhibitors (22.05% and 17.10% for BR-13 and Parana cultivars, respectively) while the amount of phytic acid decreased 15.96% and 9.46% for BR-13 and Parana cultivars, respectively.

Soybean β-Glucosidase immobilisated on chitosan beads and its application in soy drink increase the aglycones

The objective of this study was to investigate the immobilisation efficiency of soybean β-glucosidase (181.6 U/mL; 23.8 mg protein/mL) on activated chitosan beads. Central Composite Rotational Design (CCDR) 23 was used and the application of immobilised enzyme in commercial soy drink was evaluated. The activation of chitosan beads was achieved with established 2.5% glutaraldehyde, pH 7.5, 8 h incubation time (6 h with agitation and 2 h without agitation) at 37oC. The highest immobilisation efficiency (%) of soybean β-glucosidase on chitosan beads obtained was 37.74 U/mL and 18.84 mg protein/4 chitosan beads at pH 7.5 and 20 h coupling time of enzyme-matrix (7 h with agitation and 13 h without agitation) at 4oC. The immobilised enzyme incubated at 50oC, pH 5.5 resulted in 24% increase in the aglycones content in commercial soy drink after 60 min.