Abstract：
BACKGROUND: Soybean meal (SBM) is used widely in animal feed but it contains anti-nutritional factors (ANFs) such as protease inhibitors - immunogenic proteins that limit its utilization. Fermentative processes could help to reduce these ANFs. The aim of this study was to evaluate the nutritional attributes, bacterial community dynamics, and microbial metagenomic profile during the solid-state fermentation of SBM using a strain of the bacterium Lactobacillus acidophilus with or without pre-autoclaving treatment.
RESULTS: Following fermentation, there was a reduction in the pH and a concurrent increase in the population of lactic acid bacteria. Fermentation also resulted in an increase in both crude and soluble protein levels. Trypsin inhibitor levels decreased after fermentation, particularly in fermented SBM that had not been pre-autoclaved, with an inactivation rate higher than 90%. Moreover, high-molecular-weight peptides (44-158 kDa), specifically some polypeptides from the soybean immunogen glycinin and β-conglycinin, underwent degradation during the fermentation process. Bacterial community analysis revealed the dominance of the Lactobacillus genus in all samples, regardless of the treatments applied. Metagenomic profiling identified L. acidophilus as the dominant species in inoculated SBM, irrespective of whether pre-autoclaving was conducted or not.
CONCLUSIONS: This study demonstrates the feasibility of solid-state fermentation with L. acidophilus under non-sterile conditions to inactivate trypsin inhibitor and increase protein concentration and hydrolysate immunogen proteins into low-molecular-weight peptides in SBM. Lactobacillus acidophilus inoculum also inhibited the growth of undesirable bacteria. This knowledge contributes to our understanding of the potential applications of solid-state fermentation with L. acidophilus in improving the nutritional quality of SBM. © 2024 Society of Chemical Industry.
RESULTS: Following fermentation, there was a reduction in the pH and a concurrent increase in the population of lactic acid bacteria. Fermentation also resulted in an increase in both crude and soluble protein levels. Trypsin inhibitor levels decreased after fermentation, particularly in fermented SBM that had not been pre-autoclaved, with an inactivation rate higher than 90%. Moreover, high-molecular-weight peptides (44-158 kDa), specifically some polypeptides from the soybean immunogen glycinin and β-conglycinin, underwent degradation during the fermentation process. Bacterial community analysis revealed the dominance of the Lactobacillus genus in all samples, regardless of the treatments applied. Metagenomic profiling identified L. acidophilus as the dominant species in inoculated SBM, irrespective of whether pre-autoclaving was conducted or not.
CONCLUSIONS: This study demonstrates the feasibility of solid-state fermentation with L. acidophilus under non-sterile conditions to inactivate trypsin inhibitor and increase protein concentration and hydrolysate immunogen proteins into low-molecular-weight peptides in SBM. Lactobacillus acidophilus inoculum also inhibited the growth of undesirable bacteria. This knowledge contributes to our understanding of the potential applications of solid-state fermentation with L. acidophilus in improving the nutritional quality of SBM. © 2024 Society of Chemical Industry.
摘要：
背景：豆粕（SBM）广泛用于动物饲料中，但它含有抗营养因子（ANF），例如蛋白酶抑制剂-限制其利用的免疫原性蛋白质。发酵过程可以帮助减少这些ANF。这项研究的目的是评估营养属性，细菌群落动态，在SBM的固态发酵过程中，使用嗜酸乳杆菌菌株进行或不进行高压灭菌前处理。
结果：发酵后，pH值降低，乳酸菌种群同时增加。发酵还导致粗蛋白和可溶性蛋白水平的增加。发酵后胰蛋白酶抑制剂水平下降，特别是在未经预高压灭菌的发酵SBM中，具有高于90%的失活率。此外，高分子量肽（44-158kDa），特别是来自大豆免疫原大豆球蛋白和β-伴大豆球蛋白的一些多肽，在发酵过程中经历了降解。细菌群落分析揭示了乳杆菌属在所有样品中的优势,无论采用何种治疗方法。宏基因组分析将嗜酸乳杆菌鉴定为接种的SBM中的优势种，无论是否进行高压灭菌。
结论：本研究证明了在非无菌条件下用嗜酸乳杆菌进行固态发酵以灭活胰蛋白酶抑制剂并增加蛋白质浓度和水解免疫原蛋白在SBM中转化为低分子量肽的可行性。嗜酸乳杆菌接种物也抑制不良细菌的生长。这些知识有助于我们了解嗜酸乳杆菌固态发酵在改善SBM营养质量方面的潜在应用。©2024化学工业学会。
结果：发酵后，pH值降低，乳酸菌种群同时增加。发酵还导致粗蛋白和可溶性蛋白水平的增加。发酵后胰蛋白酶抑制剂水平下降，特别是在未经预高压灭菌的发酵SBM中，具有高于90%的失活率。此外，高分子量肽（44-158kDa），特别是来自大豆免疫原大豆球蛋白和β-伴大豆球蛋白的一些多肽，在发酵过程中经历了降解。细菌群落分析揭示了乳杆菌属在所有样品中的优势,无论采用何种治疗方法。宏基因组分析将嗜酸乳杆菌鉴定为接种的SBM中的优势种，无论是否进行高压灭菌。
结论：本研究证明了在非无菌条件下用嗜酸乳杆菌进行固态发酵以灭活胰蛋白酶抑制剂并增加蛋白质浓度和水解免疫原蛋白在SBM中转化为低分子量肽的可行性。嗜酸乳杆菌接种物也抑制不良细菌的生长。这些知识有助于我们了解嗜酸乳杆菌固态发酵在改善SBM营养质量方面的潜在应用。©2024化学工业学会。
