In-situ analysis of fruit anthocyanins by means of total internal reflectance, continuous wave and time-resolved spectroscopy

Abstract

In sweet cherry (Prunus avium), the red pigmentation is correlated with the fruit maturity stage and can be measured by non-invasive spectroscopy. In the present study, the influence of varying fruit scattering coefficients on the fruit remittance spectrum (cw) were corrected with the effective pathlength and refractive index in the fruit tissue obtained with distribution of time-of-flight (DTOF) readings and total internal reflection fluorescence (TIRF) analysis, respectively. The approach was validated on fruits providing variation in the scattering coefficient outside the calibration sample set. In the validation, the measuring uncertainty when non-invasively analyzing fruits with cw method in comparison with combined application of cw, DTOF, and TIRF measurements showed an increase in r² up to 22.7 % with, however, high errors in all approaches.

Estimation of cotyledon isoflavone abundance by a grey luminance-based model in variously hilum-coloured soybean varieties

“…In vegetables and fruits, anthocyanins are responsible for various colours according to the type and abundance of coloured compounds, which may be represented as grey luminance distribution. In this study, the hilum tissues of our soybeans exhibited contrasting pixel luminance distribution in high‐resolution images.…”

“…Recent literature also confirms that some enzymes like F3H and IFS are co-expressed during seed development, but with a difference in the timing of peak activity, which reduces competition for their substrate naringenin. 27 In vegetables and fruits, anthocyanins are responsible for various colours according to the type and abundance of coloured compounds, 28 which may be represented as grey luminance distribution. In this study, the hilum tissues of our soybeans exhibited contrasting pixel luminance distribution in high-resolution images.…”