蓝莓多酚在发酵酸奶贮藏期稳定性研究

Stability of Blueberry Polyphenols in Fermented Yoghurt during Storage Period

探究在常温贮藏条件下,蓝莓果浆、蓝莓全脂酸奶、全脂酸奶理化指标中总固形物、蛋白质、脂肪、pH等含量变化,同时进行总多酚含量、抗氧化活性、自由基消除能力变化观察,试验设计贮藏期为28 d,对样品进行检测。结果显示,添加蓝莓果浆的蓝莓全脂酸奶相比全脂酸奶对照的总固体含量、脂肪、蛋白质和酸度均有所提升,分别为总固体含量21.06%、脂肪3.48 g/100 g、蛋白质4.18 g/100 g和酸度94.55°T,同时其pH降低到4.32。贮藏期间全脂酸奶、蓝莓全脂酸奶的总酚含量变化差别不显著,但两者的总酚含量及稳定性均低于蓝莓果浆。蓝莓全脂酸奶抗氧化活性高于全脂酸奶,在贮藏期28 d时达到42.06±0.84 mg/100 g,蓝莓果浆的总抗氧化活力最高。蓝莓全脂酸奶的ABTS+自由基清除能力相比蓝莓果浆显著降低,在贮藏期降幅为26.1%,到贮藏期结束时达到52.71±1.7mg/100 g。蓝莓全脂酸奶在贮藏期28 d色度值分别为L*57.64, a*4.55和b*3.78。

The changes of total solids,protein,fat and pH in the physical and chemical indexes of blueberry pulp,blueberry whole fat yogurt and whole fat yogurt were observed under the condition of normal temperature storage.In addition,the changes of total polyphenol content,antioxidant activity and free radical elimination ability were observed.In the 28 d of experimental design storage period,the samples were tested.The results showed that the total solid content,fat,protein and acidity of blueberry whole fat yoghurt added with blueberry pulp were 21.06% total solid content,3.48 g/100 g fat,4.18 g/100 g protein and 94.55 °T acidity respectively,and the pH decreased to 4.32.Although the difference in total phenol content between whole fat yogurt and blueberry whole fat yogurt during storage was not significant,the total phenol content and stability of both were lower than that of blueberry pulp.The antioxidant activity of blueberry whole fat yogurt was higher than that of whole fat yogurt,reaching 42.06±0.84 mg/100 g at 28 d of storage,and the total antioxidant activity of blueberry pulp was the highest.The ABTS+ free radical scavenging capacity of blueberry whole fat yogurt was significantly lower than that of blueberry pulp,which decreased by 26.1% during the storage period and reached 52.71±1.7 mg/100 g at the end of storage period.The color values of blueberry full fat yogurt were L* 57.64,a* 4.55 and b* 3.78 on the 28 d of storage.