Abstract
Improvement of nutritional value and reduction of antinutritional factors (ANFs) of soybean meal (SBM) for animal feed applications could be achieved by using bromelain immobilized onto bentonite (Bt)-carboxymethylcellulose (CMC) composites. The composite with mass ratio between CMC to calcium ion (Ca2+) at 1:20 provided the highest enzyme activity, immobilization yield higher than 95%, with superior thermal and storage stabilities. Performance of the immobilized bromelain for soybean protein hydrolysis was further studied. The results showed that at 60 °C, the immobilized bromelain exhibited the highest efficiency in enzymatic hydrolysis to release free alpha amino nitrogen (FAN) as a product with high selectivity and to effectively reduce SBM allergenic proteins within 30 min. In conclusion, immobilization of bromelain onto Bt-CMC composites leads to stability enhancement of the enzyme, enabling effective improvement in SBM quality in a short treatment time and showing great potential for application in animal feed industries.