无硫复合护色液对干制红富士苹果片中可滴定酸和可溶性糖含量的影响

目的]研究红富士苹果干制过程中无硫复合护色液对果片中的可滴定酸和可溶性糖含量的影响。方法]分别以一定浓度的氯化钠(0.7%)、氯化钙(0.6%)、柠檬酸(0.7%)、EDTA-2Na(0.16%)、异抗坏血酸钠(1.3%)和复合护色液(氯化钠1.0%、氯化钙0.6%、柠檬酸0.9%、EDTA-2Na 0.16%、异抗坏血酸钠1.6%)浸泡苹果片2 h,取出,沥干,放入恒温干燥箱中干制(60℃),考察不同护色剂对干制苹果片中可滴定酸和可溶性糖含量的影响。结果]试验表明,不同护色剂均能显著抑制干制果片中的可滴定酸和可溶性糖含量的下降,其中以柠檬酸和无硫复合护色液对果片中可滴定酸含量下降抑制效果最好;以异抗坏血酸钠和无硫复合护色液对果片中可溶性糖含量下降抑制效果最好。结论]研究认为,无硫复合护色液护色的主要机理是通过抑制果肉中的氧化酶活力和延缓抗氧化酶活力的下降来实现的。

Effect of Sulfur-Free Complex Colour-Protective Reagents on Titratable Acid and Soluble Sugar Levels in Drying "Fuji" Red Apples

Objective] To investigate the effect of sulfur-free complex colour-protective reagents on titratable acid and soluble sugar levels in drying "Fuji" red apples.Method] Apple slices were dipped in NaCl(0.7%),CaCl2(0.6%),citric acid(0.7%),EDTA-2Na(0.16%),sodium-D-isoascrobate(1.3%) or complex colour-protective liquid(NaCl 1.0%,CaCl2 0.6%,citric acid 0.9%,EDTA-2Na 0.16%,sodium-D-isoascrobate 1.6%) liquid,respectively,for 2 h.Then,apple slices were taken out and dried at 60 ℃ in a electrothermal constant temperature drying box.Result] The results showed that all kinds of selected colour-protective reagents could delay the decrease of titratable acid and soluble sugar levels in drying apple slices.Among them,effect of citric acid and complex colour-protective liquid against the decrease of titratable acid content in drying slices was the best.Effect of sodium-D-isoascrobate and complex colour-protective liquid against the decrease of soluble sugar content in drying slices was the best.Conclusion] It was thought that sulfur-free complex colour-protective liquid can prevent apples slices brown mainly by inhibiting oxidase enzymes activity and delaying the decrease of antioxidant enzymes activity when drying.