超高压处理的草莓果肉饮料在贮藏过程中的品质变化

 采用超高压处理（压力600 MPa、保压时间4 min）方法，实验研究了在4 ℃下储藏7个月时草莓果肉饮料的微生物及主要品质的变化。结果表明：草莓果肉饮料在7个月贮藏期内没有细菌、霉菌或酵母检出，仅从微生物角度看，超高压处理有效地延长了货架期；贮藏过程中草莓果肉饮料中的颜色逐渐变暗，可溶性固形物、pH值、可滴定酸有波动，但变化不显著（P>0.05），总酚、维生素C及花青素含量均逐渐减少，·DPPH（1，1-二苯基-2-三硝基苯肼）自由基清除能力及铁离子还原能力逐渐减弱；贮藏过程中草莓果肉饮料挥发性香气成分的种类和含量均发生明显变化，其中酯类成分显著降低，芳樟醇和反式-橙花叔醇随储藏时间的延长而显著增加。

Quality Changes of Strawberry Nectar Processed by Ultra High Pressure during Storage

The bacterial phase and qualities of strawberry nectar treated by ultra high pressure (600 MPa, 4 min) at storage of 4 ℃ for seven months are studied. The experimental results show that there are no aerobic bacteria, yeasts or molds detected in the strawberry nectar during storage, from the microbial safety point of view, which indicates that ultra high pressure processing at 600 MPa for 4 min can be used as an alternative preservation method for extending its shelf life. No significant changes are observed for the total soluble solid content, pH value and titratable acidity during storage. However, the color gradually darkens, the contents of total phenols, vitamin C and anthocyanins significantly decrease (P<0.05), and the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging capacity and ferric reducing ability of plasma decrease (P<0.05) with the prolongation of the storage period. In addition, the esters in the strawberry nectar significantly reduce, and the relative contents of the representative aromatic compounds including linalool and nerol in the strawberry nectar increase dramatically during the storage process (P<0.05).