基于Z-score评价模型优化梨膏护色工艺

Optimization of Color Protection Technology of Pear Paste Based on Z-score Evaluation Model

为优化鸭梨膏护色工艺,以褐变度、总酚、总黄酮含量和感官评价得分结果为基础建立Z-score(Z值)法综合评价模型,以Z值为评价指标,通过单因素试验和响应面试验确定鸭梨膏最佳护色参数,并采用电子鼻和电子舌对护色和未护色鸭梨膏的气味和滋味进行比较分析。结果表明:鸭梨膏最优护色工艺为抗坏血酸添加量0.02%(m/v)、柠檬酸添加量0.05%(m/v)、偏重亚硫酸钾添加量0.02%(m/v),在此条件下,鸭梨膏呈亮黄色半透明膏状,带有梨果特殊香味,酸甜感适中,感官得分为9.38,褐变度为0.201,总酚和总黄酮含量分别为59.80和80.10μg/mL,Z值法综合评价得分为5.14,与理论值5.03接近。电子鼻可以准确区分护色和未护色的梨膏。电子舌分析表明护色鸭梨膏具有明显的丰富度和酸味。

In order to optimize the color protection technology of‘Yali’pear paste,a Z-score(Z value)comprehensive evaluation model was established based on browning degree,total phenolics,total flavonoids content,and sensory score analysis and then the Z value was employed to optimize the color protection parameters for“Yali”pear paste through single factor tests and response surface methodolog(RSM).The flavour and taste of“Yali”pear paste prepared under optimized conditions and without color protection were tested with electronic nose and electronic tongue technology,respectively.Results showed that the optimum process conditions for“Yali”pear paste color protection were added amount of sodium ascorbate 0.02%(m/v),citric acid 0.05%(m/v)and potassium metabisulfite 0.02%(m/v).“Yali”pear paste prepared under the optimized conditions showed a semitransparent state with bright yellow color,special pear flavour,moderate sour and sweet feeling,its browning degree,total phenolics,total flavonoids content and the sensory score were 0.201,59.80,80.10μg/mL and 9.38 respectively.Moreover,its Z-value for comprehensive evaluation method was 5.14,closing to the theoretical value of 5.03.The electronic nose technology made a perfect distinction on flavour between the optimized condition and without color protection of“Yali”pear paste.The electronic tongue analysis showed that“Yali”pear paste prepared under optimized conditions aroused stronger signals than paste without color protection in taste richness and sour sensors.