葡萄糖-柠檬酸溶液浸渍处理对冻干苹果片品质的影响

Effects of immersion treatment with glucose and citric acid solutions on the quality of freeze-dried apple slices

为了研究葡萄糖和柠檬酸溶液浸渍处理对冻干苹果片品质的影响,通过单因素试验测定并分析不同质量分数葡萄糖、柠檬酸溶液浸渍处理后冻干苹果片的主要品质指标,再用响应面分析法优化浸渍处理的葡萄糖-柠檬酸溶液最佳质量分数组合。单因素试验结果表明,高质量分数(25%)葡萄糖溶液浸渍处理可使冻干苹果片获得较高的色差值、产出率、形变率和硬度;高质量分数(4%)柠檬酸溶液浸渍处理可使冻干苹果片获得相对较高的色差值、复水比、形变率及相对较低的产出率、硬度。通过中心组合响应面试验,利用加权系数法将色差值、形变率、产出率和硬度等4个指标转化成综合指标。结果表明,葡萄糖质量分数越高、柠檬酸质量分数越低,所得冻干苹果片的综合指标越高。响应面优化的最佳浸渍溶液质量分数组合为25%葡萄糖+1%柠檬酸,在该组合溶液浸渍处理下的冻干苹果片色差值为9.67,形变率为14.82%,产出率为17.26%,硬度为4.43 N,获得的综合指标回归模型的决定系数(R2)=0.95,具有较好的品质预测能力。

In order to study the effects of immersion treatment with glucose and citric acid solutions on the quality of freeze-dried apple slices,the main quality indicators of freeze-dried apple slices were analyzed by single factor test.The combination of glucose and citric acid in immersion treatment was optimized by response surface methodology.The results of single factor test showed that immersion treatment with high mass fraction(25%)of glucose solution could contribute to higher chromatic aberration,yield rate,deformation rate and hardness of freeze-dried apple slices.The freeze-dried apple slices obtained relatively higher chromatic aberration,rehydration ratio and deformation rate,showed relatively lower yield rate and hardness after immersion treatment with high mass fraction(4%)of citric acid solution.In the experiment of central composite design combined with response surface methodology,the comprehensive index was calculated by the four indicators such as chromatic aberration,deformation rate,yield rate and hardness through using the weighted coefficient method.The results indicated that the higher mass fraction of glucose and the lower mass fraction of citric acid resulted in the higher comprehensive index of freeze-dried apple slices.The optimal combination by response surface method was 25%glucose and 1%citric acid.Under this condition,the chromatic aberration,deformation rate,yield rate and hardness of the freeze-dried apple slices were 9.67,14.82%,17.26%,4.43 N,respectively.The determination coefficient(R2)for the regression model of the comprehensive index was 0.95,which showed good ability in quality prediction.