电子舌在甜菊糖甜味特性评价中的应用

Evaluation of Steviol Glycosides Sweetness Taste by Electronic Tongue

采用电子舌技术结合主成分分析，以蔗糖为参比物，对 5 种不同组成的甜菊糖样品（RA95、RA97、RA99、RA/RB（90/10）、RA/RD（90/7）），进行了甜味特性评价研究，评价结果与感官评价结果进行了对比。甜菊糖溶液质量浓度 0.2～0.8 g/L 时，等同甜度的蔗糖溶液质量溶度为 0.03～0.09 g/mL，相对蔗糖甜度倍数为 90～220，在口腔内的甜味持续时间为 10～60 s，质量浓度 1.2 g/L 的 5 种甜菊糖溶液均呈现出明显苦味。电子舌可以准确识别 5种不同类型甜菊糖样品，判别指数为 100。在主成分分析得分图的 PC1 和 PC2 轴上，电子舌能够识别不同浓度的蔗糖和甜菊糖溶液，电子舌对相同浓度的甜菊糖溶液甜味强度识别结果为 RA/RD（90/7）＞RA95＞RA/RB（90/10）和RA99＞RA97＞RA95，识别结果与感光评价结果一致。通过计算主成分得分图上的组间距离，电子舌判定 3 种RA 系列甜菊糖与蔗糖的相似度最高的为 RA99，其次为 RA97 和 RA95。结果表明，电子舌技术在代替人工感官进行甜味评价方面有很好的应用前景。

There is an urgent need in the food and beverages industry for evaluation of the sweetness taste by using a rapid and objective method. An electronic tongue was used to evaluate sweetness taste and compare different steviol glycosides （different compositions of rebaudioside A： RA95, RA97, RA99, RA/RB（90/10）, RA/RD（90/7） ）. Five RA samples and sucrose used as a reference were analyzed by the electronic tongue and sensory panels. Sensory analysis demonstrated that the RA samples （0. 2 ~ 0. 8 g/L） were 90 -220 times sweeter than that of sucrose （0.03 -0. 09 g/mL）. The data obtained by electronic tongue was analyzed by principal component analysis （PCA）. The extinction time of all RA samples ranged from 10 s to more than 60 s, and RA at 1.2 g/L exhibited intense bitter taste. Five RA samples were successfully discriminated on the PCA score plot. Compared with sucrose at different concentrations, the intensity of sweetness taste of RA samples was ranked as： RA/RD（90/7 ） 〉 RA95 〉 RA/RB（90/10） and RA99 〉 RA97 〉 RA95. Based on euclidean distance on the PCA score plot, RA99 was revealed more similar taste than that of RA95 and RA97. The results showed that the electronic tongue analysis might be a useful method to complement sensory panels in evaluation of sweetness.