辣椒面颗粒度对辣椒油理化性质和挥发性风味物质的影响

Study on the effects of granularity of paprika on physicochemical properties and volatile flavor compounds of chili oil

目的:研究辣椒面颗粒度对辣椒油理化性质和挥发性风味物质的影响。方法:采用高效液相色谱、色差仪等测定不同颗粒度(35,30,26,20目)机械粉碎的辣椒面制备辣椒油样品(KLD2-KLD5)的辣椒素类物质含量、色差和过氧化值,利用气相色谱-离子迁移谱(GC-IMS)结合主成分分析(PCA)、偏最小二乘判别分析(PLS-DA)、热图聚类分析等多元统计方法对辣椒油样品的挥发性风味物质的种类和含量进行测定和统计学分析,并与传统手工磨制辣椒油样品(KLD1)进行对比。结果:KLD2-KLD5辣椒油样品中,辣椒素含量、二氢辣椒素含量、辣椒素类物质总量、斯科维尔指数和辣度均随辣椒面颗粒度的增大而减小,过氧化值随辣椒面颗粒度的增大而增大,亮度L^(*)随辣椒面颗粒度的减小呈先增加后减小趋势(P<0.05)。经GC-IMS共鉴定出58种挥发性有机化合物(VOCs),主要包括醇类10种、醛类18种、酮类12种、羧酸类4种、酯类7种、杂环类5种、硫醚类2种。由GC-IMS指纹图谱结合VOCs的相对百分含量可知,KLD2-KLD5样品的VOCs种类相同,含量各有差异;KLD1样品的VOCs种类和含量与KLD2-KLD5的差异较大。经PLS-DA共筛选出5种辣椒油的关键差异标志物14种。5种辣椒油样品VOCs的PCA、最邻近分析、热图聚类分析结果与GC-IMS指纹图谱结果一致,能将各样品准确区分,KLD1风味最为独特。结论:辣椒面颗粒度对辣椒油中辣椒素和二氢辣椒素的溶出率、过氧化值、亮度L^(*)影响较大且差异显著(P<0.05),对辣椒油挥发性风味化合物的种类无明显影响,但各样品的VOCs含量存在一定差异。

Objective:This study aimed to investigate the effects of granularity of paprika on the physical and chemical properties and volatile flavor compounds of chili oil.Methods:Chili oil samples(KLD2-KLD5)were prepared from mechanically crushed paprika with different granularity(35,30,26,20 mesh),and the content of capsaicinoids,chromatic aberration value,and peroxide value of oil samples were determined by high performance liquid chromatography(HPLC),colorimeter and other methods.The types and contents of volatile flavor compounds were detected and analyzed by gas chromatography-ion mobility spectrometry(GC-IMS)combined with principal component analysis(PCA),partial least squares discriminant analysis(PLS-DA),and heat map cluster analysis.In addition,a comparative analysis was performed with the traditional hand-milled chili oil sample(KLD1).Results:In the KLD2-KLD5 chili oil samples prepared with mechanically crushed paprika,the concentration of capsaicin,dihydrocapsaicin and capsaicinoids,scoville heat units(SHU)and pungency degree decreased with the increase of the granularity of paprika.The peroxide value increases with the increase of the granularity,and the brightness L^(*)increased first and then decreased with the decrease of the granularity,and there was a significant difference(P<0.05)had been observed.A total of 58 volatile organic compounds(VOCs)were identified by GC-IMS,mainly including:alcohols,aldehydes,ketones,carboxylic acids,esters,heterocyclics and thioethers,with 10,18,12,4,7,5 and 2 types respectively.GC-IMS fingerprints combined with the relative percentage of VOCs showed that the types of VOCs in KLD2-KLD5 samples were the same,but the contents were different.The types and content of VOCs in KLD1 were quite different from those in KLD2-KLD5.Fourteen key differential markers of 5 chili oils were screened by PLS-DA.The results of principal component analysis,nearest neighbor analysis,and heat map clustering analysis of VOCs in five kinds of chili oil samples were consistent with the results of GC-IMS fingerprints.These samples could be accurately distinguished and the flavor of KLD1 was the most unique.Conclusion:The granularity of paprika had a significant impact on the dissolution rate of capsaicin and dihydrocapsaicin in chili oil,peroxide value,and brightness L^(*)(P<0.05),but has no effect on the types of volatile flavor compounds in chili oil.However,the content of volatile flavor compounds in each sample had a certain difference.