Non-destructive estimation of anthocyanin content in yardlong bean based on tristimulus values and reflectance spectra

Traditionally, the quantification of anthocyanin content requires destructive sampling followed by chemical analysis with elaborate process. The aim of this study was to use non-destructive methods for prediction of anthocyanin by using color values from handheld colorimeter. Five hundred and fifty-eight yardlong bean samples that have pale green to dark purple pod color were used for color measurement and anthocyanin analysis. The partial least square regression (PLSR) was used to correlate spectral data with anthocyanin content. The PLSR model could predict anthocyanin content with correlation coefficient of 0.900 and standard error of prediction of 1.994 A/gFw. The results indicated that colorimeter readings can be correlated with anthocyanin content in yardlong bean and could be used as an alternative to chemical analysis. This method is reliable, rapid and inexpensive and can be used to screen a large number of yardlong bean accessions or populations under high anthocyanin breeding program.