School of Food & Biological Engr, Jiangsu Univ, Xuefu Road 301# Zhenjiang City, Jiangsu Province 212013, PR China.
J Food Sci. 2012 Feb;77(2):C222-7. doi: 10.1111/j.1750-3841.2011.02549.x. Epub 2012 Jan 17.
Total acid content (TAC) and soluble salt-free solids content (SSFSC) in Chinese vinegar are 2 important indicators in the assessment of its quality. This paper shows the feasibility to determine TAC and SSFSC in Chinese vinegar by near-infrared (NIR) spectroscopy. Synergy interval partial least square (Si-PLS) algorithm was performed to calibrate the regression model. The number of PLS factors and the number of intervals were optimized simultaneously by cross-validation. The performance of the model was evaluated according to root mean square error of prediction (RMSEP) and correlation coefficient (R) in the prediction set. The optimum Si-PLS model for TAC was achieved with RMSEP = 0.264 g/100 mL and R(p) = 0.9655; the optimum Si-PLS model for SSFSC was achieved with RMSEP = 1.93 g/100 mL and R(p) = 0.9302. The overall results demonstrated that NIR spectroscopy combined with Si-PLS could be utilized to determinate TAC and SSFSC in Chinese vinegar, and NIR spectroscopy has a potential to be used in vinegar industry.
总酸含量（TAC）和可溶性无盐固形物含量（SSFSC）是评价中国食醋质量的两个重要指标。本文展示了利用近红外（NIR）光谱法测定中国食醋中 TAC 和 SSFSC 的可行性。采用协同区间偏最小二乘法（Si-PLS）算法对回归模型进行校准。通过交叉验证同时优化 PLS 因子数和区间数。根据预测集中的预测均方根误差（RMSEP）和相关系数（R）评估模型的性能。TAC 的最优 Si-PLS 模型的 RMSEP = 0.264 g/100 mL 和 R(p) = 0.9655；SSFSC 的最优 Si-PLS 模型的 RMSEP = 1.93 g/100 mL 和 R(p) = 0.9302。总体结果表明，NIR 光谱法结合 Si-PLS 可用于测定中国食醋中的 TAC 和 SSFSC，NIR 光谱法有望用于食醋行业。
