超声波对猕猴桃片的渗糖效果及干燥能耗与品质的影响

【目的】研究不同的超声波工艺参数对猕猴桃片渗糖效果及干燥能耗与特征品质的影响,建立数学回归模型并优化工艺参数,为超声渗糖技术用于生产高品质、低能耗的猕猴桃片提供理论依据。【方法】试验以猕猴桃为原料,选取时间、温度、蔗糖浓度、超声声能密度为因素,以猕猴桃的固形物增加率（solids gain,SG）、水分损失率（water loss,WL）、单位能耗、可滴定酸、含糖量、色差（ΔE）、L*、a*、b*、硬度、黏性、弹性、黏聚性、胶黏性、咀嚼性、回复性、叶绿素保存率、维生素C保存率、可溶性固形物为指标,进行四因素Box-Benhnken响应面试验,利用因子分析筛选出评价猕猴桃片品质的特征指标,建立单位能耗及猕猴桃片特征指标的二次多项式回归方程模型,分析影响各指标的主次因素及因素间的交互作用,优化得出猕猴桃片超声渗糖工艺的最佳参数,并加以验证。【结果】猕猴桃片的品质特征指标分别为回复性、ΔE、含糖量、WL、可滴定酸、维生素C保存率;建立的猕猴桃片单位能耗和品质特征指标的回归模型具有统计学意义（P<0.05）。各因子对含糖量影响的大小依次是蔗糖浓度>时间>温度>声能密度,时间和温度、温度和蔗糖浓度、蔗糖浓度和声能密度的交互作用均为极显著,温度和声能密度的交互作用显著。各因子对WL影响的大小依次是时间>声能密度>蔗糖浓度>温度,时间和温度及时间和声能密度的交互作用显著。各因子对单位能耗影响的大小依次是蔗糖浓度>时间>声能密度>温度,温度和蔗糖浓度的交互作用显著。各因子对回复性影响的大小依次是时间>蔗糖浓度>温度>声能密度,蔗糖浓度和声能密度交互作用显著。各因子对ΔE影响的大小依次是蔗糖浓度>温度=声能密度>时间;各因子对可滴定酸影响的大小依次是时间>声能密度>蔗糖浓度>温度,时间和声能密度交互作用显著;各因子对维生素C保存率影响的大小依次是蔗糖浓度>温度>时间>声能密度。猕猴桃片超声渗糖工艺参数为：时间58 min、超声温度47℃、蔗糖浓度40 °Brix、超声声能密度0.7 W·mL ^-1,在此条件下猕猴桃片的单位能耗为18.15 kJ·g ^-1、回复性为0.172、ΔE为15.51、含糖量为35.03%、WL为27.85%、可滴定酸为1.58%、维生素C保存率为92.23%。 【结论】因子分析法能提取出评价猕猴桃片品质的特征指标。建立的二次多项式回归模型可分别用于分析和预测超声波处理参数对猕猴桃片的渗糖效果及干燥能耗与品质的影响。超声浸糖处理具有渗糖速率快、破坏小等优点,处理后的猕猴桃片单位能耗较低、质地品质较好,超声波处理可用于猕猴桃片的渗糖工艺。

Effects of Ultrasound on the Sugar Permeability Effect,Drying Energy Consumption and Quality of Kiwifruit Slices

【Objective】 This research aimed to investigate the effects of ultrasonic on the sugar permeability effect, drying energy consumption and quality of kiwifruit slices and its mathematical model and then the process parameters was optimized to provide a theoretical basis for the application of ultrasonic osmosis technology to produce high quality and low energy kiwifruit slices.【Method】 Taking the kiwifruit as the raw material, the ultrasonic density, time, temperature and sucrose concentration were selected as the factors, and the solids gain (SG), water loss (WL), unit energy consumption, titratable acid, sugar content, color difference (ΔE), L*, a*, b*, hardness, adhesiveness, springiness, cohesiveness, gumminess, chewiness, resilience, chlorophyll preservation rate, vitamin C preservation rate and soluble solid were selected as indicators. The box Benhnken test with four factors was designed, and the characteristic index for evaluating the quality of the kiwifruit slices was screened out using factor analysis. The two polynomial regression equation model of the unit energy consumption and the quality characteristic index of the kiwifruit slices were established. The primary and secondary factors and interactions of the effects were analyzed, and the optimal parameters of the ultrasonic infiltration process of kiwifruit slices were optimized and verified. 【Result】 The characteristic index for evaluating the quality of the kiwifruit slices were resilience, ΔE, sugar content, WL, titratable acid and vitamin C preservation rate. The regression model of the energy consumption and quality characteristics of kiwifruit slices was statistically significant (P<0.05). The order of the effect of each factor on sugar content was sucrose concentration>time>temperature>ultrasonic density, and the interactions between time and temperature, temperature and sucrose concentration, sucrose concentration and ultrasonic density were extremely significant. The interaction between temperature and ultrasonic density was significant. The order of the effect of each factor on WL was time>ultrasonic density>sucrose concentration>temperature, and the interactions between time and temperature and time and ultrasonic density were significant. The order of the effect of each factor on unit energy consumption was sucrose concentration>time>ultrasonic density>temperature, and the interaction between temperature and sucrose concentration was significant. The order of the effect of each factor on resilience was time>sucrose concentration>temperature>ultrasonic density, and the interaction between sucrose concentration and ultrasonic density was significant. The order of the effect of each factor on ΔE was sucrose concentration> temperature=ultrasonic density>time. The order of the effect of each factor on titratable acid was time>ultrasonic density>sucrose concentration>temperature, and the interaction between time and ultrasonic density was significant. The order of the effect of each factor on the retention rate of vitamin C was sucrose concentration> temperature>time>ultrasonic density. The optimal process parameters for ultrasonic infiltration of kiwifruit slices were ultrasonic time of 58 min, temperature of 47℃, sucrose concentration of 40 °Brix, and ultrasonic density of 0.7 W·mL ^-1. Under these conditions, the unit energy consumption of kiwifruit slices was 18.15 kJ·g ^-1, the recovery was 0.172, ΔE was 15.51, the sugar content was 35.03%, the WL was 27.85%, the titratable acid was 1.58%, and the vitamin C retention rate was 92.23%.【Conclusion】 The factor analysis method could extract the characteristic indexes for evaluating the quality of kiwifruit slices. The established quadratic polynomial regression model could be applied to analyze and to predict the effects of ultrasonic treatment parameters on the osmotic effect, drying energy and quality of kiwifruit slices. Ultrasonic treatment had the advantages of fast sugar infiltration rate, little damage, lower energy consumption and better texture quality. Ultrasonic treatment could be used in the kiwifruit infiltration process.