藜麦黑枸杞酸奶的工艺优化及其抗氧化活性研究

Study on the Process Optimization of Quinoa Black Medlar Yogurt and Its Antioxidant Activity

以藜麦和黑枸杞作为复合添加物,以黏附力和感官评分为评价指标,考察藜麦浆、黑枸杞粉、木糖醇及乳酸菌添加量对藜麦黑枸杞无糖酸奶品质的影响。通过单因素和正交试验对酸奶工艺进行优化,并对产品的理化及微生物指标、乳酸菌数及抗氧化性进行研究。结果表明,藜麦黑枸杞无糖酸奶最优参数为:藜麦浆25%,黑枸杞粉1.0%,木糖醇8%,乳酸菌添加量1.0%。在此工艺条件下制作的酸奶,具有发酵酸乳和藜麦黑枸杞复合香味,感官评分达到93.2分,黏附力为-2.35 N,各项理化和微生物指标符合发酵乳食品安全国家标准。藜麦黑枸杞酸奶对DPPH自由基和羟自由基的IC;值分别为6.1和8.9 mg/mL,清除能力均高于对照组酸奶(35.9和40.5 mg/mL),且在贮藏过程中自由基清除能力均表现出不同程度的升高。

Using quinoa and black medlar as compound additives, the adhesion and sensory scores were used as indicators to investigate the effects of quinoa slurry, black medlar powder, xylitol and lactic acid bacteria inoculation on quinoa black medlar sugar free yogurt. For the influence of quality, orthogonal experiment was carried out on the basis of single factor experiments to optimize the yogurt craft formula, and conduct research on physiochemical indexes, microbiological indexes, lactic acid bacteria counts and antioxidant activities. Results showed that the optimal processing parameters were as follows: Guinoa slurry 25%, black medlar powder 1.0%, xylitol 8%, lactic acid bacteria inoculation 1.0%. The yogurt made under this process had rich aroma of quinoa and black medlar, a sensory score of 93.2 and an adhesion of-2.35 N. At the same time, the physiochemical and microbiological indexes, lactic acid bacteria counts met the corresponding national food safety standard for yogurt. The IC;of DPPH and hydroxyl radicals in quinoa black medlar yogurt were 6.1 and 8.9 mg/mL, respectively, and the scavenging abilities were higher than those of the control group(35.9 and 40.5 mg/mL).The scavenging ability of DPPH and hydroxyl radical increased in different degrees during storage.