Method For Nondestructive Measurement Of Beta-Cryptoxanthin In Satsuma Mandarins (Citrus Unshiu Marcow.) Using Visible And Near-Infrared Spectroscopy

Satsuma mandarins (Citrus unshiu Marcow.) are one of the most commonly eaten domestic fruits in Japan, and recent studies have shown that the beta-cryptoxanthin present in Satsuma mandarins might provide benefits to bone health. In this study, we examined whether the use of visible and near-infrared (VIS-NIR) spectroscopy, and a new simplified measuring system for beta-cryptoxanthin in satsuma mandarins, which has recently been developed as an alternative method of HPLC, permit us to rapidly quantify beta-cryptoxanthin in single intact fruits. Satsuma mandarins, harvested in 2016, were subjected to VIS-NIR radiation, and spectra were collected from 600-970 nm at 1-nm intervals, with an integration time of 10 ms. beta-cryptoxanthin contents of each sample were then measured by a newly developed simplified measuring system. We then examined the associations between VIS-NIR spectra data and beta-cryptoxanthin contents obtained from the simplified measuring system. Calibration models were prepared using partial least squares regression (PLSR) on pre-treated spectra in the ranges 0.52-3.44 mg/100 g (beta-cryptoxanthin) of 340 samples. External validation was carried out with 340 new samples. The PLSR models for intact satsuma mandarins were able to predict beta-cryptoxanthin with R-2= 0.897, RMSEP = 0.169, and RPD =3.01. The results allow for the market valorization of this fruit.