Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, 306 Zhaowuda Street, Hohhot 010018, China.
Molecules. 2018 Apr 11;23(4):878. doi: 10.3390/molecules23040878.
The lactic acid bacterium is a major starter culture for the production of dairy products. In this study, the physiochemical characteristics of milk fermented by the MGA45-4 isolate of were analyzed. Our data indicate that milk fermented using MGA45-4 maintained a high viable cell count (8.86 log10 colony-forming units/mL), and a relatively high pH (4.4), viscosity (834.33 mPa·s), and water holding capacity (40.85%) during 14 days of storage. By analyzing the volatile compound profile using solid-phase microextraction and gas chromatography/mass spectrometry, we identified 73 volatile compounds in the fermented milk product, including five carboxylic acids, 21 aldehydes, 13 ketones, 16 alcohols, five esters, and 13 aromatic carbohydrates. According to the odor activity values, 11 of these volatile compounds were found to play a key role in producing the characteristic flavor of fermented milk, particularly octanal, nonanal, hexanal, 2,3-butanedione, and 1-octen-3-ol, which had the highest odor activity values among all compounds analyzed. These findings thus provide more insights in the chemical/molecular characteristics of milk fermented using , which may provide a basis for improving dairy product flavor/odor during the process of fermentation and storage.
该乳酸菌是乳制品生产中的主要起始培养物。在这项研究中，分析了 MGA45-4 分离株发酵牛奶的理化特性。我们的数据表明，使用 MGA45-4 发酵的牛奶在 14 天的储存期内保持了高活菌数（8.86log10 菌落形成单位/mL），相对较高的 pH 值（4.4）、粘度（834.33mPa·s）和持水能力（40.85%）。通过固相微萃取和气相色谱/质谱联用分析挥发性化合物图谱，我们在发酵乳产品中鉴定出 73 种挥发性化合物，包括五种羧酸、21 种醛、13 种酮、16 种醇、五种酯和 13 种芳香碳水化合物。根据气味活性值，这 11 种挥发性化合物被发现对产生发酵乳的特征风味起着关键作用，特别是辛醛、壬醛、己醛、2,3-丁二酮和 1-辛烯-3-醇，它们在所有分析的化合物中具有最高的气味活性值。这些发现为使用该乳酸菌发酵牛奶的化学/分子特性提供了更多的见解，这可能为在发酵和储存过程中改善乳制品的风味/气味提供了依据。
