乳酸菌发酵豆腐乳清的风味特征研究

Studies on the Flavor Characteristics of Tofu Whey Fermented by Lactobacillus

豆腐乳清为豆制品生产过程中产生的黄色沥水,其中含有大量的营养物质,若直接排放则会造成资源浪费与环境污染。对豆腐黄浆水进行综合开发利用具有重要意义。本研究从自然酸化的豆腐黄浆水中分离筛选出5株乳杆菌,包括哈尔滨乳杆菌M1、黏膜乳杆菌M2、发酵乳杆菌M4、鼠李糖乳杆菌C1、解淀粉乳杆菌L6以及从直投式发酵剂中分离筛选并驯化的嗜热链球菌ST3联合发酵豆腐乳清,通过核磁共振氢谱和气相色谱-质谱方法探究其发酵前、后代谢物和挥发性成分的变化。结果表明,从核磁共振氢谱中检出25种物质,包括糖类、酸类、氨基酸类,以及具有生物活性的4-氨基丁酸(GABA)和胆碱。采用GC-MS共检出95种挥发性风味成分,发酵后大部分醛类物质消失,C1+ST3组与L6+ST3组分别在酯类和酮类物质方面有所增加。用两种分析方法均检测到短链脂肪酸乙酸、丙酸和丁酸。本研究表明乳酸菌发酵使豆腐乳清产生特征性的风味物质和部分功能性物质,这为豆腐乳清的开发应用奠定了试验基础。

Tofu whey is a yellow drain produced during the production of soy products.It contains a large amount of nutrients that may cause waste of resources and environmental pollution if discharge it directly.Therefore,it is of great significance to comprehensively develop and utilize tofu whey.In this study,we use five Lactobacillus species(Lactobacillus harbinensis M1,Lactobacillus mucosae M2,Lactobacillus fermentum M4,Lactobacillus rhamnosus C1,Lactobacillus amylolyticus L6),which were isolated and screened from natural acidified tofu whey,and use Streptococcus thermophilus ST3,which was isolated and screened in the commercial starter,to ferment tofu whey.The changes of metabolites and volatile components before and after fermentation were investigated by nuclear magnetic resonance(NMR)spectroscopy and gas chromatography-mass spectrometry(GC-MS).The results showed that 25 substances were detected in the NMR spectrum,including sugars,acids,amino acids,biologically active 4-aminobutyric acid(GABA)and choline;95 kinds of volatile flavor components were detected by GC-MS from fermented tofu whey.Most of the aldehydes disappeared after fermentation.The ester and ketone content of C1+ST3 group and L6+ST3 group increased respectively.Short chain fatty acids acetic acid,propionic acid and butyric acid were detected by both analytical methods.This result indicates that the metabolism of Lactobacillus produced many functional compounds and flavor components in tofu whey,which laid the foundation for the development and application of tofu whey.