电子舌分析山西老陈醋固态发酵过程及主要有机酸的预测

Analysis of the solid-state fermentation of Shanxi aged vinegar and prediction of key organic acids using electronic tongues

山西老陈醋是我国著名的传统食醋之一,主要采用固态发酵工艺,在醋酸发酵过程中产生的有机酸赋予了老陈醋独特的口感和风味。采用HPLC和电子舌的方法对山西老陈醋醋酸发酵阶段的样品进行分析,发现乙酸和乳酸是醋酸发酵阶段的主要有机酸,占总酸的60%以上,利用电子舌结合主成分分析和聚类分析可以明显区分不同发酵时间的醋醅样品。进一步,采用BP神经网络建立了发酵过程中乙酸和乳酸的定量预测模型,测试样品预测值和实测值相关系数分别为0.961 5和0.994 2,均方根误差分别为54.4 mg/100 g和59.0 mg/100g,表明该模型可用于发酵过程中乙酸和乳酸的定量预测。该文提供了利用电子舌对发酵过程中的关键代谢产物的含量进行预测的方法,为食醋规模化生产提供了现场快速分析的智能质量监控手段。

Shanxi aged vinegar, one of famous vinegars in China, is brewed using traditional solid-state fermen- tation technology. During the fermentation process, abundant organic acids which give the vinegar unique taste and flavor are produced. In this research, the samples of acetic acid fermentation were analyzed using the method of HPLC and electronic tongues, respectively. Results showed that acetic acid and lactic acid were the main organic acids which accounted for over 60% of total acids and the samples could be distinguished with the data acquired from the e- lectronic tongues by using the method of principal component analysis （PCA） and cluster analysis （CA）. Further- ＂more, back propagation neural network （BP NN） was used to construct a model for quantitative prediction of acetic acid and lactic acid. For the testing samples, the correlation coefficients of acetic acid and lactic acid between ob- served and predicted values were 0. 961 5 and 0. 994 2 and the root mean standard errors of prediction were 54.4mg/ 100g for acetic acid and 59.0mg/100g for lactic acid, respectively. It was indicated that this model could be used for quantitative prediction of acetic acid and lactic acid during the fermentation process. Thus, this research suggested a rapid method to analyze key organic acids, which could be used for scale-up production of vinegar.