Quality evaluation of flue-cured tobacco leaves at different oil levels in Henan based on comprehensive weighting method

【Objective】Based on the differences of chemical composition and sensory quality of tobacco leaves at different oil levels, a comprehensive weight evaluation system was established, and the quality evaluation methods of tobacco leaves with different oil levels were established to evaluate the availability of tobacco leaves with different oil levels, which provided reference for the quality evaluation and utilization of high-oil and high-quality tobacco leaves.【Method】The chemical composition and sensory quality indicators of 132 samples of Yunyan 87 tobacco leaves at different oil levels(a little, less oily, oily and rich) covered by the full leaf position in Lingbao, Sanmenxia, Henan tobacco area were used as the data set, and the chemical and sensory quality indicators were assigned values using the affiliation function, and then the indicators were re-assigned weights through the principal component weighting method, coefficient of variation weighting method, subjective weighting method and comprehensive weighting method, so as to evaluate the availability of tobacco leaves at different oil levels.【Result】With the leaf oil level from a little to rich, with an overall decreasing trend of total nitrogen, chloride and nitrogen to alkali ratio, the total nitrogen content of a little oil level tobacco leaves was 5.15%-46.41% higher than that of tobacco leaves at other oil levels; and total sugar, reducing sugar, total alkaloids and potassium content showed an increasing trend, the contents of total sugar and reducing sugar in rich oil level tobacco leaves were 12.20%-28.96% and 10.09%-30.64% higher than those in tobacco leaves at other oil levels respectively. Except for total plant alkaloids and nitrogen alkali ratio indicators, the oil level of tobacco leaves was significantly(P<0.05) or extremely significantly(P<0.01, the same below) correlated with the other seven chemical indicators. With the leaf oil level from a little to rich, the scores of sensory quality indicators and total scores showed an increasing trend, and the oil level of the tobacco leaves was extremely significantly and positively correlated with all the sensory indicators scores. Compared with the single weighting method, the comprehensive weighting method improved the discrimination of the usability index of tobacco leaves with different oil levels. With the oil level of tobacco decreased, the availability index greatly decreased, and the availability index of rich oil level tobacco leaves was the highest(0.644-0.749). The results of correlation analysis showed that the comprehensive weighting method was strongly correlated with the results of each single weighting method.【Conclusion】The comprehensive weighting method based on the chemical composition index and sensory quality index of tobacco leaves can be used as a scientific and effective method to evaluate the availability of tobacco leaves at different oil levels, and provide a quality evaluation method for the subsequent production evaluation of high-oil tobacco leaves.