为探究水开菲尔粒发酵草莓汁在冷藏期间的品质稳定性,本研究对发酵草莓汁在4℃下冷藏28d期间的主要理化指标、活性物质、抗氧化能力、活菌数及感官特性的变化进行了综合检测.结果显示,在冷藏期间,发酵草莓汁的总酚、总黄酮和VC含量均有下降,相应的其抗氧化能力包括SOD酶活性、DPPH自由基清除率和ABTS+自由基清除率分别降低了 16％、8.5％和28.3％.乳酸菌和酵母菌活菌数分别减少了 12.8％和14％,醋酸菌活菌数增加了 16％.感官评价中,除气味得分升高外,因L*与a*的降低,b*的升高,发酵草莓汁色泽评分降低,同时,悬浮稳定性和pH的下降,使组织状态和滋味得分也出现降低,但得分均在6分以上.总体上,在冷藏期间,水开菲尔粒发酵草莓汁的主要理化指标和活性物质稳定性较强、乳酸菌等活菌数仍保持在6 lg CFU/mL以上,抗氧化能力仍保持65％以上的较高活性,感官评定也在可接受范围,说明水开菲尔粒发酵草莓汁的综合品质在冷藏28 d内可保持较高稳定性.
Analysis of the Quality Stability of Strawberry Juice Fermented with Water Kefir Grains during Refrigeration
To investigate the quality stability of strawberry juice fermented with water kefir grains during refrigeration.Variations in the primary physical and chemical parameters were analyzed,together with analysis of the active compounds,antioxidant capacity,viable bacterial and yeast counts,and sensory attributes of the fermented strawberry juice over a 28 day refrigeration period at 4 ℃.Results showed that during refrigeration,the total phenol,total flavonoid,and vitamin C contents in the fermented strawberry juice decreased.Correspondingly,the antioxidant capacity,including the activity of superoxide dismutase and the DPPH and ABTS+free radical-scavenging rates were reduced by 16％ ,8.5％ ,and 28.3％ ,respectively.The viable lactic acid bacterial and yeast counts decreased by 12.8％ and 14％ ,respectively,while the counts of viable acetic acid bacteria increased by 16％ .In the sensory evaluation,in addition to the observed increase in the odor score,the color score of the fermented strawberry juice decreased due to reductions in the and a*values and an increase in the b* value.At the same time,reductions in the suspension stability and pH also led to lower scores for texture and taste,however,these scores still remained above 6 points.During refrigeration,the main physical and chemical indicators,as well as the levels of active substances,in the strawberry juice fermented with water kefir grains,were found to be relatively stable.The number of viable lactic acid bacteria was above 6 lg CFU/mL,while the antioxidant capacity remained at a high level of more than 65％ .In addition,the results of the sensory evaluation fell within the acceptable range.These findings indicated that the overall quality of water kefir grains-fermented strawberry juice remained stable over 28 days of refrigeration.
water kefir grainsstrawberry juicerefrigerationquality
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