不同胶体对黑莓果汁花色苷稳定性的影响研究

本文探讨了黄原胶、果胶、羧甲基纤维素钠（CMC）、海藻酸钠、壳聚糖等5种常用胶体对黑莓果汁在储藏期内稳定性的影响，分别测定了各体系的pH、色泽、花色苷含量和流变性质的变化。结果表明，5种胶体对黑莓果汁花色苷储藏期间pH影响较小，能够维持体系呈酸性环境。加入一定浓度（低于0.075%）的胶体可以减缓黑莓果汁花色苷的降解，其中加入0.05% CMC或0.10%黄原胶，储藏2周内花色苷降解速率低于未加胶体组，色差ΔE值最小。流变学测定显示CMC或黄原胶通过提高黑莓果汁花色苷体系的黏度和储能模量使体系稳定；同时，扫描电子显微镜结果显示，黄原胶、CMC等胶体能与黑莓果汁花色苷体系相互作用，形成片状或多孔状结构。CMC或黄原胶是黑莓果汁花色苷理想的辅色素之一。

Effects of Different Colloids on the Stability of Anthocyanins in Blackberry Juice

In this study,the effects of different colloids(xanthan gum,pectin,CMC,sodium alginate and chitosan)on the stability of anthocyanin from blackberry juice during processing and storage were investigated by measuring the pH values,color,anthocyanin contents and rheological properties.The results demonstrated that the degradation rates of blackberry juice anthocyanins were decreased with the addition of xanthan gum,pectin,CMC,sodium alginate and chitosan at a certain concentration(less than 0.075%).Therein the color and stability were obviously enhanced with 0.05%CMC or 0.10%xanthan addition,which was confirmed by the lowestΔE value and lower degradation rate.The rheology results showed that the viscosities and storage modulus of juices were increased in the presence of CMC or xanthan.Additionally,some sheet and porous structures were observed by SEM,suggesting the co-pigmentations between anthocyanins and colloids,which consequently resulted in the deduced molecular movement and the enhanced stability of anthocyanins.It is noted that CMC or xanthan is one of the best co-pigments for blackberry anthocyanins.