Relationship of the optical properties with soluble solids content and moisture content of strawberry during ripening
Dandan Xie, Dayang Liu and Wenchuan Guo
Postharvest Biology and Technology, Volume 179, September 2021, 111569
2021
บทคัดย่อ
To understand the relationship of optical properties with soluble solids content (SSC) and moisture content of strawberry during ripening, a single integrating sphere system was built to estimate the absorption coefficient (µa) and reduced scattering coefficient (µs') of strawberry in white, color turning and red ripening stages over the wavelength range of 550−850 nm and 950−1650 nm. The relationship between optical properties and SSC and moisture content was analyzed, and the determination models for SSC and moisture content were established by using partial least squares regression and support vector machine methods based on the spectra of µa, µs', and µa together with µs'. The results showed that the absorption peaks of strawberry were at 675, 975, 1197 and 1411 nm, and the µs' generally decreased with increased maturity of strawberry. The µa was positively correlated with SSC and negatively correlated with moisture content, while the µs'was positively correlated with moisture content and negatively with SSC. The best correlations of µa with SSC and moisture content were found at 1411 nm with the correlation coefficients of 0.72 and -0.74, respectively. The established support vector machine models based on the µa spectra in 950−1650 nm and 550−850 nm had the smallest root-mean-squares error of calibration set of 0.98 % and 0.89 % for SSC and moisture content, respectively. This study indicates that SSC and moisture content mainly affect the absorption property of strawberry, and µa has greater potential than µs' and µa together with µs' in determining the internal quality of strawberry.