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 本研究旨在开发基于比色法的果蔬总花青素含量预测简易数学模型。本研究采用70%酸化乙醇与70%乙醇两种溶剂，制备了13种果蔬的酚类提取物；通过分光光度法定量提取物的总花青素含量，并借助三刺激比色仪完成色泽表征。对于经20倍稀释的70%乙醇提取物，其L*值与花青素含量间具有极强相关性（相关系数r=-0.95）。分别以70%乙醇、70%酸化乙醇为提取溶剂，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特定溶剂的快速检测方法，可用于预测果蔬的总花青素含量。