功能性牦牛酸奶制备、贮藏期内品质及降嘌呤活性研究

于鑫迪; 刘静雅; 任秀梅; 陈炼红

doi:10.13386/j.issn1002-0306.2023090042

功能性牦牛酸奶制备、贮藏期内品质及降嘌呤活性研究

Preparation, Quality and Purine-lowering Activity of Functional Yak Yoghurt during Storage Period

摘要

摘要: 为研发一款降嘌呤的功能性牦牛酸奶，以副干酪乳杆菌259和商业发酵剂为发酵菌株，通过单因素实验优化牦牛酸奶菌株接种量，观察牦牛酸奶后熟期及贮藏期品质变化，利用气相色谱-质谱联用技术（GC-MS）解析后熟期和贮藏贮藏期的风味物质变化，高效液相色谱法（HPLC）测定牦牛酸奶的降嘌呤活性。结果表明：牦牛酸奶后熟24 h时，副干酪乳杆菌259接种量5%时感官评分最优，活菌数3.1×10⁸ CFU/mL，酸度为96°T，对黄嘌呤氧化酶（xanthine oxidase，XOD）的抑制率为51.51%。5%接种量副干酪乳杆菌259的牦牛酸奶在贮藏期28 d内活菌数高于10⁷ CFU/m L，酸度低于105.4°T，随贮藏时间增加，pH及持水力逐渐降低，感官品质、硬度、内聚力、黏度、稠度以及对XOD抑制活性先上升后下降；牦牛酸奶后熟期主要风味物质是醇类、酯类、酮类、芳香杂环类以及含硫化合物，贮藏期比后熟期增加了酸类物质；醇类化合物的相对含量和数量最多，赋予酸奶水果香气、花香和甜味；贮藏期牦牛酸奶对肌苷和鸟苷的降解率先上升后下降，最高可达84.6%和86.5%。由此可见，副干酪乳杆菌259发酵的牦牛酸奶品质较好，可抑制黄嘌呤氧化酶活性，有效降解肌苷鸟苷，在预防和辅助治疗高尿酸血症上有较好的应用潜力。

Abstract: In order to develop a purine-reducing functional yak yoghurt, Lactobacillus paracasei 259 and commercial starter was used as the fermentation strain in this experiment. The inoculation amount of yak yoghurt strain was optimized by single factor experiment, and the quality changes of yak yoghurt during post-ripening period and storage period were observed. Gas chromatography-mass spectrometry (GC-MS) was used to analyze the changes of flavor substances during post-ripening period and storage period, and the purine-lowering activity of yak yoghurt was determined by high performance liquid chromatography (HPLC). The results showed that the post-ripening time of yak yoghurt was 24 h, the sensory score was the best when the inoculation amount of Lactobacillus paracasei 259 was 5%, the number of viable bacteria was 3.1×10⁸ CFU/mL, the acidity was 96°T, and the inhibition rate of xanthine oxidase (XOD) was 51.51%. Yak yogurt with 5% inoculum of Lactobacillus paracasei 259 had a viable bacterial count higher than 10⁷ CFU/mL during 28 d of storage, and the acidity was lower than 105.4°T. With the increase of storage time, the pH and water holding capacity decreased gradually, and the sensory quality, hardness, cohesion, viscosity, consistency and XOD inhibitory activity increased first and then decreased. The main flavor substances in yak yogurt after ripening were alcohols, esters, ketones, aromatic heterocycles and sulfur compounds. The acids increased at storage period compared to the post-ripening period. The relative content and quantity of alcohols were the highest, which gave the yogurt a fruity, floral and sweet flavor. The degradation of inosine and guanosine in yak yogurt during the storage period firstly increased and then decreased, up to 84.6% and 86.5%, respectively. It can be seen that yak yogurt fermented by Lactobacillus paracasei 259 is of better quality, inhibits xanthine oxidase activity, effectively degrades inosine guanosine, and has good potential for application in the prevention and adjunctive treatment of hyperuricemia.