Analysis of Physicochemical Indexes and Quality of Aged Vinegar Based on Partial Least Squares Regression Method
With three types of commercially available aged vinegar in large supermarkets in Nanyang city as the research object,the content of total acids,non-volatile acids and pH value of aged vinegar are compared and analyzed by referring to the national standard testing method.Using near-infrared spectroscopy technology combined with partial least squares regression quantitative analysis method,the optimal inlet optical path,optimal flow rate and optimal pretreatment method are determined.Under these conditions,discriminant analysis is conducted on the three types of aged vinegar to determine the method for analyzing the physicochemical indexes of aged vinegar based on partial least squares regression method.The results show that the three types of aged vinegar samples all meet the pH value for aged vinegar specified by the national standard(pH 3.6～3.9),with pH values of 3.71±0.02,3.65±0.01,3.82±0.01 respectively.The content of total acids and non-volatile acids of the three types of aged vinegar samples is slightly different,ranging from(0.567±0.011)g/L to(0.593±0.02)g/L and from(0.148±0.012)g/L to(0.215±0.018)g/L respectively.In near-infrared spectroscopy testing,in terms of the selection of the optimal optical path,the optimal optical path for pH value detection and non-volatile acid detection after removing abnormal samples is 3 mm,and the optimal optical path for total acid detection is 2 mm.In terms of the selection of flow rate of aged vinegar,the flow rate for pH value detection and total acid detection should be controlled at 0.2 L/min,and the flow rate for non-volatile acid detection should be controlled at 0.6 L/min.In terms of the selection of spectral pretreatment conditions,SNV pretreatment method should be selected for pH value detection and non-volatile acid detection,while the five-point smoothing pretreatment method should be selected for total acid detection.The results show that near-infrared spectroscopy combined with partial least squares regression method can be used to detect the physicochemical properties of aged vinegar,with good detection effect and high detection efficiency.
aged vinegarpartial least squares regression methodphysicochemical indexes
NETL
NSTL
万方数据
维普
