超声和渗透预处理对干燥草莓片品质及抗氧化活性影响

研究蔗糖、果糖、葡萄糖以及蔗糖结合超声渗透预处理对真空冷冻联合热风干燥草莓片品质及其抗氧化活性影响。结果表明:经预处理后干燥草莓片的品质、花色苷、总酚、黄酮、Vc含量和抗氧化能力均有显著性差异(p0.05),其中蔗糖结合超声前处理水分含量最低,硬度最高,而经蔗糖渗透处理的草莓片干燥后色泽与新鲜草莓最接近,a*最高;干燥后草莓片的花色苷、总酚和黄酮含量均高于鲜样,但Vc含量大大降低,其中经蔗糖结合超声预处理后的草莓片花色苷、总酚和黄酮含量最高,分别为22.68 g/L、7.52 mg/g、10.38 mg/g,其对-OH和DPPH清除率也高于其他组,但渗透和超声处理并不能提高草莓片Vc含量和铁离子还原能力;三种糖渍处理均能提高干燥草莓片品质,且蔗糖效果最佳。综上,渗透以及蔗糖结合超声预处理后草莓片品质以及抗氧化活性成分含量较高、抗氧化活性较强,适宜于草莓片的干燥。

Effects of Ultrasonic and Osmotic Pretreatment on Quality and Antioxidant Activity of Dried Strawberry Slices

The effects of sucrose, fructose, glucose and sucrose combined with ultrasonic osmotic pretreatment on the quality and antioxidant activity of vacuum freezing combined with hot air drying strawberry slices were studied. The results showed that the quality, anthocyanin, total phenol, flavonoids, VC content and antioxidant capacity of dried strawberry slices were significantly different after pretreatment (p<0.05). The water content of sucrose-ultrasonic pretreatment was the lowest, and the hardness was the highest. The color of dried strawberry slices with the highest a* was the closest to that of fresh strawberry. The contents of anthocyanins, total phenols and flavonoids in dried strawberry slices were higher than that in fresh samples, but the content of Vc was greatly reduced. The contents of anthocyanins, total phenols and flavonoids in dried strawberry slices pretreated by sucrose combined with ultrasound were 22.68 g/L, 7.52 mg/g and 10.38 mg/g, respectively. The scavenging rate of -OH and DPPH were also higher than that in other groups, but the permeation rate was higher. Ultrasound and Vc content of strawberry slices could not be improved, and the three kinds of sugar treatment could improve the quality of dried strawberry slices, and the sucrose treatment was the best. In conclusion, the quality and antioxidant activity of strawberry slices pretreated by osmosis and sucrose combined with ultrasound were higher, which was suitable for the drying of strawberry slices.