[6-1015-C] Postharvest/Food Technology and Process Engineering (6)

[6-1015-C-01] Spatially Resolved Interactance Spectroscopy to Estimate Degree of Red Coloration in Red-fleshed Apple Cultivar 'Kurenai-no-Yume'

*Xujun Ye¹, Sou Takada¹, Shuhuai Zhang¹ (1. Hirosaki University(Japan))

Keywords:Red-fleshed apple, Kurenai-no-Yume, Red coloration, Interactance spectroscopy, Anthocyanin, Non-destructive estimation, Partial least squares regression

Reliable information about degree of red coloration in fruit flesh is essential for grading and sorting of red-fleshed apples. This study used spatially resolved interactance spectroscopy as a new rapid and non-destructive technique to estimate degree of red coloration in the flesh of a red-fleshed apple cultivar ‘Kurenai-no-Yume’. A novel measurement device was developed to obtain spatially resolved interactance spectra at eight different light source-detector separations. A UV-Vis-NIR spectrometer connected to the detector fiber was used to obtain interactance spectra ranging from 190~1070 nm for 50 apple fruits. Anthocyanins in apple flesh were first extracted using a solvent extraction technique, and their contents were then quantified based on the absorbance measurements at 530, 620 and 650 nm obtained with a spectrophotometer. Partial least squares (PLS) regression analysis was performed to develop estimation models for anthocyanins content from spatially resolved interactance spectra. Results showed that the PLS models based on interactance spectra obtained at different light source-detector separations achieve different predictive accuracy for anthocyanins estimation. These results suggest that spatially resolved interactance spectroscopy could contribute to identifying an optimal light source-detector distance for implementing the interactance spectroscopy to assess the internal quality of red-fleshed apples. This new approach may be potentially applied to grading and sorting systems for red-fleshed apples in fruit industry.