Despite their important bioactivities, the unpleasant bitter taste of citrus derived flavonoids limits their applications in the food industry, and the structure–bitterness relationship of flavonoids is still far from clear.

Loquat is a popular fruit widely cultivated all over the world. It is rich in minerals and carotenoids and has high commercial value. At room temperature, loquat fruit is impressionable to water and nutritional losses, physical damage, and microbial decay, resulting in a short postharvest life. Low-temperature storage is routinely used to prolong the shelf life of loquat fruit; however, cold storage can also lead to lignification of flesh tissue, which is one of the major symptoms of chilling injury (CI), reducing the quality and economic value of the fruit. In addition, fruit decay caused by microbial infection is another important reason for postharvest losses of loquat. To reduce quality deterioration and optimize the postharvest storage strategies of loquat fruit, considerable progress has been made in the physiological and molecular biological studies of CI, microbial decay, and preservation technologies of loquat fruit during the postharvest phase in recent decades. This review summarizes the current research progress and provides a reference for the improvement of loquat fruit quality.

The primary cause of postharvest loss in table grape fruit is attributed to gray mold, which is caused by Botrytis cinerea. The present study confirmed the inhibitory effects of nystatin on the growth and development of B. cinerea, which led to a remarkable reduction in the severity of gray mold on table grape fruits. Furthermore, the application of nystatin disrupted the membrane permeability of B. cinerea, causing increased cellular leakage and cell death. In addition, the transcriptome analysis showed that the application of nystatin effectively modulated the transcriptional profile of genes involved in ribosome and mitochondrion biogenesis, as well as oxidoreductase activity, thereby disrupting the homeostasis of cellular organelles. Moreover, the nystatin treatment down-regulated genes associated with membrane trafficking, protein degradation by the ubiquitin–proteasome system, and the autophagy process, ultimately attenuating the pathogenicity of B. cinerea. Collectively, nystatin can be considered a viable agent for managing gray mold on table grape fruit.

Currently, it is difficult to distinguish the inner quality of pachycarpous fruits using nondestructive instruments, and trace nutrients and flavor compounds are rarely considered in fruit sorting. In this study, the external features and internal quality indices of an extensively farmed citrus fruit, the Guanxi honey red pomelo, were measured. The correlation between the inner and external quality was analyzed using Pearson correlation, canonical correlation, and grey correlation analyses. This research innovatively introduced bitter substances and revealed that the height-diameter ratio could serve as a predictor for ultra-size fruits, which partially reflects inner quality indices. Several grey formulas were developed to express these correlations and were fitted to a matrix, which demonstrated accuracies at all level 1 (C < 0.35, P > 0.95). Based on the matrix, fruit quality analysis of white and red pomelo showed high prediction accuracy in TSS and bitter substance indices (R2 = 0.6 – 0.8) and indicated that mature and symmetrical pomelo (height-diameter ratio of 0.9 – 1.1) exhibit a similar quality pattern. This study achieved rapid quality assessment using easy measurable shape characteristics and explored the application of characteristic bitter substances in the quality evaluation model, providing theoretical references and potential application guidance for pachycarpous fruit sorting, as well as introducing a new idea to incorporating characteristic quality into modeling index.

Natural plant-derived chalcones exhibit sweetening properties and bioactive health benefits, making them promising natural sweeteners.However, their unsatisfying sweetness intensity restricts their applications in the food industry.