Aspergillus oryzae GB-107 fermentation improves nutritional quality of food soybeans and feed soybean meals.
This study evaluated the effect of fermentation on the nutritional quality of food-grade soybeans and feed-grade soybean meals. Soybeans and soybean meals were fermented by Aspergillus oryzae GB-107 in a bed-packed solid fermentor for 48 hours. After fermentation, their nutrient contents as well as trypsin inhibitor were measured and compared with those of raw soybeans and soybean meals. Proteins were extracted from fermented and non-fermented soybeans and soybean meals, and the peptide characteristics were evaluated after electrophoresis. Fermented soybeans and fermented soybean meals contained 10% more (P < .05) crude protein than raw soybeans and soybean meals. The essential amino acid profile was unchanged after fermentation. Fermentation eliminated (P < .05) most of the trypsin inhibitor from both soybeans and soybean meals. Fermentation increased the amount of small-size peptides (<20 kDa) (P < .05) compared with raw soybeans, while significantly decreasing large-size peptides (>60 kDa) (P < .05). Fermented soybean meal contained more (P < .01) small-size peptides (<20 kDa) than soybean meal. Fermented soybean meal did not contain large-size peptides (>60 kDa), whereas 22.1% of peptides in soybean meal were large-size (>60 kDa). Collectively, fermentation increased protein content, eliminated trypsin inhibitors, and reduced peptide size in soybeans and soybean meals. These effects of fermentation might make soy foods more useful in human diets as a functional food and benefit livestock as a novel feed ingredient.
Hong
Kee-Jong
KJ
Department of Pathology, Texas Tech University Health Sciences Center, Texas Tech University, Lubbock, TX 79409, USA.
Lee
Chan-Ho
CH
Kim
Sung Woo
SW
D000596:Amino Acids / Q000032:analysis / Q000737:chemistry; D001236:Aspergillus oryzae / Q000378:metabolism*; D004044:Dietary Proteins / Q000032:analysis*; D004591:Electrophoresis, Polyacrylamide Gel; D005285:Fermentation; D005511:Food Handling / Q000379:methods; D005516:Food Microbiology; D006801:Humans; D008970:Molecular Weight; D009753:Nutritive Value; D030262:Soybean Proteins / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D013025:Glycine max / Q000737:chemistry / Q000378:metabolism; D014361:Trypsin Inhibitors / Q000032:analysis
D000596:Amino Acids; D004044:Dietary Proteins; D030262:Soybean Proteins; D014361:Trypsin Inhibitors