基于非靶向代谢组学的mTGase脱脂水牛乳酸奶营养及风味特性分析

Analysis of Nutrition and Flavor Characteristics of mTGase-Treated Skimmed Buffalo Milk Yogurt Based on Untargeted Metabolomics

摘要:

水牛乳因高营养价值而备受关注,然而高脂肪含量限制了其在现代健康饮食中的应用。以脱脂水牛乳为原料,通过微生物谷氨酰胺转氨酶(microbial transglutaminase,mTGase)交联技术与乳酸菌发酵工艺,开发了一种新型脱脂水牛乳酸奶。结果表明,通过mTGase交联处理的脱脂水牛乳酸奶在蛋白质、脂肪等营养成分含量上与对照组无显著差异(P>0.05)。电子鼻、电子舌分析表明,mTGase组酸奶中指示芳烃化合物和烷烃类及脂肪族化合物含量的电子鼻传感器信号值分别增加了10.31%和10.38%,而指示含硫化合物含量的电子鼻传感器信号值降低了9.63%；苦味和苦味回味分别增加了6.72%和10.92%,而甜味降低了15.84%。游离脂肪酸(free fatty acids, FFA)分析表明,经mTGase处理后,不饱和FFA含量增加,有助于增强酸奶的心血管健康相关功能活性,且长链FFA含量的增加使脱脂水牛乳酸奶口感更加润滑。游离氨基酸组成分析表明,脱脂水牛乳酸奶氨基酸组成发生显著变化,对健康有益的半胱氨酸含量从对照组的(2.894±0.026)mg/mL提升至(3.150±0.054)mg/mL；但异亮氨酸含量显著提高至(1.508±0.063) mg/mL,使酸奶具有一定苦味。非靶向代谢组学分析结果表明,mTGase处理主要引起氨基酸代谢通路的改变,部分苦味游离氨基酸上调,使得酸奶中苦味增加；但mTGase交联处理也使酸奶产生了更多的二肽及三肽类物质,提升了酸奶的潜在的心血管健康相关功能活性。另外,mTGase交联处理后,酸奶在气味和滋味上发生的改变可能与氨基酸、脂质和碳水化合物变化有关。研究旨在为脱脂水牛乳酸奶的开发提供理论依据,并揭示mTGase在改善脱脂水牛乳酸奶风味、营养功能方面的潜在应用价值。

Abstract:

Buffalo milk has garnered significant attention due to its high nutritional value. However, its high-fat content limits its application in modern healthy diets. A novel skimmed buffalo milk yogurt was prepared using microbial transglutaminase (mTGase) cross-linking technology combined with lactic acid bacteria fermentation. The results showed that there was no significant difference (P>0.05) in the contents of protein, fat, and other nutritional components between the mTGase-treated skimmed buffalo milk yogurt and the control group. Electronic nose and electronic tongue analyses indicated that in the mTGase-treated yogurt, the contents of aromatic compounds and alkanes and aliphatic compounds increased by 10.31% and 10.38%, respectively, while sulfur-containing compounds decreased by 9.63%. Bitterness and bitter aftertaste increased by 6.72% and 10.92%, respectively, whereas sweetness decreased by 15.84%. Analysis of free fatty acids (FFA) revealed that mTGase treatment increased the content of unsaturated FFAs, which may enhance cardiovascular health-related functional activity. Additionally, the increase in long-chain FFAs contributed to a smoother texture. Analysis of free amino acid composition showed significant changes in the amino acid profile of the yogurt. The content of cysteine (Cys), which is beneficial to health, increased from (2.894±0.026)mg/mL in the control group to (3.150±0.054)mg/mL in the mTGase-treated group. However, the content of isoleucine (Ile) significantly increased to (1.508±0.063)mg/mL, imparting a certain bitterness to the yogurt. Untargeted metabolomics results showed that mTGase treatment primarily altered amino acid metabolic pathways, leading to the upregulation of some bitter free amino acids, thereby increasing the bitterness of the yogurt. Nevertheless, mTGase cross-linking also promoted the formation of more dipeptides and tripeptides, enhancing the potential cardiovascular health-related functional activity of the yogurt. Furthermore, the changes in the odor and taste of the yogurt after mTGase treatment might be related to alterations in amino acids, lipids, and carbohydrates. This study aimed to provide a theoretical basis for the development of skimmed buffalo milk yogurt and to reveal the potential application value of mTGase in improving the flavor and nutritional functionality of yogurt.