新型燕麦酸奶制作工艺及其理化性质分析

Processing Technology of A New Type of Oat Yogurt and Its Physical and Chemical Properties Analysis

以燕麦乳及复原乳为原料,市售酸奶发酵菌种为发酵剂,开发一种新型燕麦酸奶。以感官评分及酸度为指标,通过单因素实验探究燕麦乳与复原乳的复配比、菌种添加量、发酵时间、发酵温度4个因素对燕麦酸奶发酵效果的影响。在单因素实验的基础上采用正交试验确定燕麦酸奶的最优发酵工艺,并对燕麦酸奶的基本理化指标包括蛋白质、脂肪、氨基酸、酸度、pH进行测定分析,通过ABTS和DPPH自由基清除能力分析燕麦酸奶的抗氧化活性,通过气质联用法测定燕麦酸奶中风味物质。结果表明,燕麦酸奶的最优发酵工艺为:燕麦乳/复原乳为2:1,发酵菌种接种量为0.2%,发酵时间9 h,发酵温度34℃。在此工艺条件下制得的燕麦酸奶呈均匀的米白色,口感酸甜适中,富含燕麦清香。GC-MS共检测出燕麦酸奶36种香气成分,主要为酯类、酸类和醛类。与市售酸奶相比,燕麦酸奶的蛋白质含量与其接近但脂肪含量只有其60%,且抗氧化活性及甘氨酸和精氨酸含量显著提高(P<0.05),更适合减肥人群食用。

A new type of oat yogurt was developed with oat milk and reconstituted milk as raw materials and commercial yogurt fermentation strains as starter.Sensory score and acidity were served as indexes,the effects of oat milk and reconstituted milk ratio,amount of fermentation strains,fermentation time,and fermentation temperature on the quality of oat yogurt were studied by single factor experiment.Based on the results of single factor experiment,the optimal fermentation process of oat yogurt was determined by orthogonal test.The basic physical and chemical indexes of oat yogurt including protein,fat,amino acid,acidity,pH were analyzed.The antioxidant activity of oat yogurt was evaluated by ABTS and DPPH methods,and the flavor compounds in oat yogurt were determined by GC-MS.The results showed that the optimal fermentation process of oat yogurt was as follows:Oat milk/reconstituted milk was 2:1,the inoculation amount of fermentation bacteria was 0.2%,the fermentation time was 9 hours,and the fermentation temperature was 34℃.The oat yogurt produced by optimal fermentation process presented uniform creamy-white,moderate sour and sweet taste and rich in oat fragrance.Thirty-six aroma components of oat yogurt were detected by GC-MS,including esters,acids and aldehydes.Protein content of oat yogurt was close to commercial yogurt,but the fat content of oat yogurt was only 60%of commercial yogurt.In addition,the antioxidant activity and contents of glycine and arginine of oat yogurt were significantly higher than commercial yogurt(P<0.05).Therefore,oat yogurt has higher nutritional value for public,especially for obesity.