均细化处理方式对桃果浆色泽的影响

为研究不同均细化处理方式对桃果浆色泽的影响,本试验对新鲜桃原料进行打浆和超细粉碎(50 Hz)处理,对热烫后的桃原料进行打浆、胶体磨和湿法超细粉碎(18、26、34、42和50 Hz)处理,分析不同均细化处理对桃果浆表观色泽以及物质成分的影响。通过Pearson相关系数和逐步线性回归方程分析,进一步明确均细化处理过程中影响桃果浆色泽的主要因素。结果表明,未热烫样品中,超细粉碎50 Hz,60 s处理后桃果浆的L^*、b^*、a^*值均高于打浆处理组;对于热烫桃果浆,随着研磨频率的增加,L^*、b^*和ΔE值提高,a^*值无明显变化。进一步对相关物质成分进行研究,结果表明,90℃条件下热烫1 min, 能够钝化桃果浆多酚氧化酶(PPO)活性,有效抑制酶促褐变的发生。热烫超细粉碎50 Hz,60 s处理后桃果浆总酚含量、可溶性蛋白质含量和还原糖含量最高,分别为1.58 GAE·g^-1、0.093%和2.741%。Pearson相关系数分析结果显示,桃果浆经过热烫处理,L^*值与总酚含量呈现极显著正相关,与还原糖和蔗糖含量呈现极显著负相关。逐步线性回归分析结果表明,热烫处理后,桃果浆色泽的变化主要是因为发生了美拉德反应。本研究结果为桃果浆破碎过程的品质调控以及后续加工利用提供了一定的理论基础。

Effects of Different Refining Treatments on the Color of Peach Pulp

The objective of this study was to evaluate the effect of refining treatments on the color stability of peach pulp.Processing methods included beating,colloid milling and wet ultrafine grinding at different frequencies(18,26,34,42 and 50 Hz).The fresh peach samples were processed by beating and wet ultrafine grinding at 50 Hz,and the blanched peach samples were processed by beating,colloid milling and wet ultrafine grinding at different frequencies(18,26,34,42 and 50 Hz),the effects of different refining treatments on the apparent color and substances of peach pulp were investigated.Pearson correlation and stepwise linear regression analyses were used to clarify the main factors affecting the color of peach pulp during the refining processes.Results showed that L^*,b^*and a^*values of the unblanched peach pulp sample with ultrafine grinding at 50 Hz for 60 s were higher than those of beating treatment.Compared with the non-blanched peach pulp sample,the L^*,b^*andΔE values of the blanched samples increased,while the a^*value reduced.For blanched peach pulp samples,as the grinding frequency increased,the values of L^*,b^*andΔE increased,but the value of a^*did not change significantly.Blanching at 90℃for 1 min could inactivate the PPO activity and effectively inhibited enzymatic browning.The total phenol,soluble protein and reducing sugar concentration of peach pulp sample with ultrafine grinding at 50 Hz for 60 s were 1.58 GAE·g^-1,0.093%and 2.741%,respectively.Pearson correlation analysis showed that with blanching treatment,L^*showed a significantly positive correlation with total polyphenol concentration of peach pulp,and was negatively correlated with the concentration of reducing sugar and sucrose.The apparent color of blanched peach pulp was mainly correlated to the contents of glucose and sucrose.After blanching treatment,the color change of peach pulp was mainly caused by Maillard reaction.This study could provide some technological supports for the quality control,subsequent processing and utilization of peach pulp.