Nondestructive Detection of Decay in Vegetable Soybeans Stored at Different Temperatures Using Chlorophyll Fluorescence Imaging

To achieve nondestructive evaluation of the quality of vegetable soybeans, we have applied chlorophyll fluorescence imaging, which has been used as a non-invasive technology to investigate the ripening and senescence of horticultural products. This study measured changes in chlorophyll content, color (ho), and chlorophyll fluorescence of vegetable soybean pods and seeds and rarely used a nondestructive approach to explore interior quality L-ascorbic acid content. The relationship between chlorophyll fluorescence parameters and visual quality attribute ho, and that between chlorophyll fluorescence parameters and L-ascorbic acid content were performed using partial least square regression (PLSR). Thus, the fluorescence parameters Fm, Fv, Fq_Lss, QY_Lss, and qL_Lss, which make larger contributions to evaluating ho in both whole vegetable soybeans and seeds were selected from 98 chlorophyll fluorescence parameters. Moreover, parameters Fv, Fq_Lss, QY_Lss, qP_Lss, and qL_Lss in seeds, which are important for estimating L-ascorbic acid of seeds were also determined. Most importantly, parameters Fv_Lss and Ft_Lss in whole vegetable soybeans, which may be possible to predict L-ascorbic acid content of seeds by a nondestructive detection. The chlorophyll fluorescence technique presents great potential in examining freshness and estimating the decay in vegetable soybeans.