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Mango, melon, pineapple, and carrot were processed into reconstituted fruits and vegetable cubes by conventional thermal pretreatment (TP) or high hydrostatic pressure (HHP) pretreatment at different pressures followed by freeze drying (FD). The effects of different HHP pressures on the physicochemical quality, bioactive substances, antioxidant activity, and sensory quality of FD fruits and vegetable cubes were investigated. The results showed that compared with TP, HHP significantly increased the a* and b* values, titratable acid content and antioxidant activity (1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity, hydroxyl radical scavenging capacity, and ferric reducing powder), increased the contents of total phenols, flavonoids, and ascorbic acid by 21.11%–30.27%, 59.96%–68.58%, and 13.35%–15.34%, respectively, and increased the contents of volatile alcohols and ketones to 189.65–207.82 and 59.60–81.16 μg/kg, respectively. In addition, the sensory intensities of five aroma attributes and the preferences for color, aroma and taste of HHP-pretreated FD cubes were significantly higher than those of TP-pretreated FD cubes. The sensory quality of FD fruits and vegetable cubes pre-treated at 300 and 500 MPa were closest to that of the non-treatment group. HHP pretreatment improved the antioxidant activity by increasing cell membrane permeability, thereby promoting the release of bioactive and flavor substances. Compared with conventional TP, HHP can effectively improve the quality characteristics of FD fruits and vegetable cubes.

In order to investigate the effect of ultraviolet-C (UV-C) irradiation combined with chitosan (CH) coating on the storage quality of Hami melon, changes in the physiological quality and antioxidant enzyme activities of ‘Xizhoumi 17’ Hami melon from Xinjiang were determined during storage at (5 ± 1) ℃ after the combined treatment. The results indicated that both single and combined treatments effectively delayed the changes in the storage quality of Hami melon, with the combined treatment being most effective. On the 49th day of storage, the fruit firmness of the combined group was 1.13 times higher, and the contents of soluble solids and titratable acids were 1.14 and 1.35 times higher than those of the control group, respectively; the contents of ascorbic acid and total phenols increased by 23.40% and 32.51%, respectively, and the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and peroxidase (POD) by 12.70%, 73.53%, 26.43% and 28.14%, respectively. In conclusion, UV-C combined with CH coating can effectively maintain the postharvest storage quality of Hami melon. This study can provide a reference for the postharvest preservation of Hami melon.

The potential of salicylic acid (SA) in delaying postharvest fruit senescence has been extensively documented; nevertheless, its effect on antioxidant activity and quality of 'France' prune fruit is largely unknown. The study investigated the effects of SA (0.5 mM) on postharvest quality deterioration of 'France' prune fruit. Results indicated that SA impeded the increase in respiration rate and weight loss, and mitigated the decrease of soluble solids content (SSC), titratable acidity (TA) content, firmness, and hue angle. SA sustained the ascorbate-glutathione cycle by inducing the production of ascorbic acid (AsA) and glutathione (GSH) and attenuates flavonoids, total phenols, and anthocyanins degradation by inhibiting polyphenol oxidase (PPO) activity and PdPPO. Moreover, SA significantly improved superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), peroxidase (POD), and glutathione reductase (GR) activities and gene expression levels, sustained higher 2,2′-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging capacity, ferric reducing antioxidant power (FRAP), and hydroxyl radical (·OH) inhibition capacity, and impeded the production of hydrogen peroxide (H2O2) and superoxide anion (O2•−). Overall, SA improved the antioxidant capacity by inducing the synthesis of defense response-related substances and promoting antioxidant enzyme activities to sustain the storage quality of 'France' prune fruit. [ABSTRACT FROM AUTHOR]

In recent times, the fabrication of Z-scheme heterostructures has gained popularity as an effective strategy for developing composite catalysts with photogenerated carriers that possess high redox capacity. This study introduces a novel type of direct Z-scheme heterojunction photocatalysts known as ZnS quantum dots wrapped around CoWO4 nanoparticles (ZnS-QDs@CoWO4). The results of the experiments and analysis indicate that these heterojunction photocatalysts demonstrate superior degradation of tetracycline hydrochloride in wastewater compared with individual ZnS-QDs or CoWO4. Notably, the 30ZS-CWO catalyst, with a mass ratio of 30:1 between ZnS-QDs and CoWO4, exhibited the highest photocatalytic reaction rate constant (k = 0.03427 min–1), which is 3.5 times greater than that of ZnS-QDs (k = 0.00969 min–1) and 214 times higher than that of CoWO4 (k = 0.00016 min–1). The enhanced photocatalytic performance can be attributed to two main factors. First, the use of CoWO4 nanoparticles as carriers helps in better dispersing the ZnS quantum dots, leading to increased catalytic reaction sites. Second, the formation of Z-scheme heterojunctions in the composite photocatalysts significantly boosts the redox capability of the photogenerated carriers. Furthermore, the excellent stability and recyclability of ZnS-QDs@CoWO4 heterojunction photocatalysts were validated through five-cycle experiments. This research introduces a promising approach for developing QDs-based Z-scheme photocatalysts for highly effective environmental remediation. [ABSTRACT FROM AUTHOR]