This study evaluated seasonal changes in various fruit quality attributes and the incidence of physiological disorders in the blocky and conical types of paprika cultivars using a simulated export system. The effects of three different pericarp colors were also investigated. 'Scirocco', 'DSP 7054', and 'Volante' cultivars were used as a blocky type, while 'Raon red', 'Raon orange', and 'Raon yellow' cultivars were used as a conical type with red, orange, and yellow pericarp color, respectively. The fruit was shipped at 10°C for two weeks, stored at 10°C for one week, and then transferred at 22°C for one week to simulate export by shipping. Storage temperatures and relative humidity levels greatly fluctuated in the winter season as compared to the summer season. Thus, fruit weight loss was higher in the winter season than in the summer season regardless of the cultivar type. However, the pericarp firmness was lower in the winter season. The soluble solids content and titratable acidity were higher in conical type than in the blocky type of paprika cultivar and highest in the 'Raon red' cultivar. The pericarp lightness and hue angle responded differently during the export season, depending on the pericarp color and fruit type. The incidence and severity of fruit shriveling were higher in the winter season than in the summer season, irrespective of the cultivar. Fruit shriveling was less severe in the conical type than in the blocky type, regardless of the pericarp color. Moreover, the incidence and severity of fruit softening, pedicel wilting, and pedicel browning were higher in the winter season than in the summer season. Therefore, the results indicate that the storage humidity levels likely play a pivotal role in the postharvest handling of paprika fruit quality during the seasonal export period. Thus, careful consideration of various techniques that are contingent upon the season of export and the specific type of fruit is required.

The fruit of the late season ‘Chuhwangbae’ Asian pear cultivar is prone to the incidence of physiological disorders during cold storage and following shelf life. However, pre-storage conditioning treatments have been used to reduce the incidence and severity of numerous storage disorders in cold-stored Asian pears during cold storage and shelf life. Thus, this study aimed to evaluate the effects of a pre-storage conditioning treatment at 22 °C for seven days on fruit quality attributes, the incidence and severity of physiological disorders, and targeted primary metabolites in the fruit of late season ‘Chuhwangbae’ Asian pear cultivar for a shelf life of 21 days at 22 °C following three months of cold storage at 0.5 °C with 90% of relative humidity. The peel blackening, cortex browning, core browning, and cavity were reduced by pre-storage conditioning treatment during shelf life after short-term cold storage. Although flesh firmness responded inconsistently in ealier shelf life, titratable acidity (TA) was lower in pre-storage conditioned fruit than in untreated fruit and weight loss and the ratio of soluble solids content (SSC) to TA were higher in pre-storage conditioned fruit compared to untreated fruit as a control. The cortex hue angle values of the fruit colour variables were higher in pre-storage conditioned fruit than in the untreated fruit. The pre-storage conditioning treatment notably affected threonine and total amino acids among the targeted primary metabolites during shelf life after cold storage. The correlation coefficient network indicated that the cortex browning and cavity were positively correlated with fumaric acid, sorbitol, and sucrose in the pre-storage conditioned fruit. Therefore, the results suggested that pre-storage conditioning treatment should be highly effective in reducing the incidence and severity of physiological disorders by mediating primary metabolism during the shelf life after cold storage.

Paprika fruits are susceptible to blossom-end rot (BER) during fruit growth and development. This study investigated the tissue-specific differential responses in quality attributes, mineral nutrients, and targeted major metabolites of healthy and BER-affected ‘Volidano’ yellow paprika fruits. Fruit fresh weight, fruit length and diameter, titratable acidity (TA), and peel yellowness were lower in BER fruits than in healthy fruits. K, P, and Mg contents were highest at the blossom-end tissue region of BER fruits, while the Ca, Mn, and B contents were lowest compared with the other tissues. The contents of glucose, fructose, citric acid, and malic acid were highest at the blossom-end tissue region of BER fruits. The levels of glutamine, asparagine, aspartic acid, serine, γ-aminobutyric acid (GABA), threonine, and citrulline were highest at the blossom-end tissue region of BER fruits, thereby contributing to having the highest content of total amino acids. The results of variable importance in projection scores and volcano plots indicated that oleic acid, asparagine, GABA, aspartic acid, glutamine, citrulline, and citric acid were upregulated at the blossom-end tissue region of BER fruits. The results suggest that the BER symptom could be associated not only with mineral nutrients but also with targeted major metabolites in paprika fruits.

The late-season onion cultivars were stored at 0 °C and 70% relative humidity (RH) for nine months to investigate the effects of cold storage on postharvest physiological quality, mineral nutrients, and targeted major metabolites of onion bulbs of different sizes: small (S), medium (M), large (L), extra-large (XL), and double extra-large (2XL). Among physiological responses, peel color variables, such as peel lightness (L*), chroma, and hue angle (h°) were significantly changed, while smallest bulb size onions changed the highest levels of peel L* and h°, compared to the others bulb sizes after long-term cold storage. Moreover, moisture loss during cold storage induced a decrease in bulb firmness and led to an increase in sweetness across all sizes of onion bulbs. Additionally, potassium, magnesium, total carbon, glucose, and lactic acid, free amino acids, such as tyrosine, phenylalanine, lysine, valine, tryptophan, leucine, isoleucine, γ-aminobutyric acid, and aspartic acid, and individual phenolic compounds, particularly quercetin and spiraeoside varied according to the different bulb sizes. Moreover, the targeted metabolomic analysis revealed a more dispersed metabolomic association at harvest. Conversely, after long-term cold storage, the major targeted metabolites, particularly sucrose, fructose, glucose, mineral nutrients, and free amino acids exhibited close interlinkages. The amino acids responses demonstrated that small- and medium-sized onion bulbs maintained higher storage quality than bulbs of other sizes. These findings suggest that long-term cold storage alters onion bulb quality by mediating biochemical parameter profiles and compositions. However, this effect was less significant for smaller onion bulbs.

Cadmium (Cd) is a potentially toxic element that impairs plant growth and threatens food safety and human health. This study aimed to investigate the effects of sulfur (S) supplementation on Cd uptake and tolerance in rice under hydroponic conditions. Rice seedlings were exposed to Cd stress and treated with S at different concentrations. Physiological traits, oxidative damage markers, thiol compounds, and ionomic profiles in rice plants were assessed. S supplementation reduced Cd-induced growth inhibition, restoring plant biomass. Although Cd accumulation increased with S treatment, it was accompanied by enhanced antioxidant responses, scavenging reactive oxygen species (ROS) and malondialdehyde. S application increased the production of thiol-containing compounds, including γ-glutamylcysteine, glutathione, and phytochelatins, which helped chelate Cd and sequester it in vacuoles, particularly in roots. Additionally, S supplementation altered the essential nutrient composition in rice tissues, particularly the uptake of N, P, and K, while influencing levels of Ca, Mg, and other essential elements. S supplementation enhanced rice tolerance to Cd stress by reestablishing ROS balance, activating thiol-based detoxification pathways, and regulating mineral nutrient balance. Furthermore, sulfur (S) exhibited a dual effect in plants, enhancing cadmium (Cd) uptake while also promoting its detoxification, underscoring its role in improving crop resilience in contaminated soils.