Chromatic analysis for predicting anthocyanin content in fruits and vegetables

Abstract The objective of this study was to develop simple mathematical models for the prediction of the total anthocyanin content of fruits and vegetables, using colorimetry. Phenolic extracts of 13 species of fruits and vegetables were produced using 70% acidified ethanol and 70% ethanol. The quantification of the total anthocyanins of the extracts was performed by the spectrophotometric method, and the color characterization was done through the tristimulus colorimeter. The correlation between the L* value and the anthocyanin content was high (r = - 0.95) for extracts produced with 70% ethanol and diluted 20 times. Linear equations based on colorimetric coordinates, with R2 from 0.80 to 0.99, were obtained using 70% ethanol and 70% acidified ethanol as extraction solvent, with or without dilutions. Therefore, colorimetry, as a rapid method that does not involve the use of specific solvents, can be used to predict the total anthocyanin content of fruits and vegetables.摘要 本研究旨在采用比色法（colorimetry）构建简易数学模型，以预测果蔬的总花青素含量。本研究分别以70%酸化乙醇与70%乙醇为提取溶剂，制备了13种果蔬的酚类提取物。提取物的总花青素含量采用分光光度法进行定量，颜色表征则通过三刺激色差计（tristimulus colorimeter）完成。针对经70%乙醇提取并稀释20倍的提取物，其L*值与花青素含量间呈现极强相关性（相关系数r = -0.95）。以70%乙醇、70%酸化乙醇作为提取溶剂时，无论是否进行稀释，均可得到基于比色坐标的线性方程，其决定系数R²介于0.80至0.99之间。因此，比色法作为一种无需使用特殊溶剂的快速检测手段，可用于预测果蔬中的总花青素含量。