Search

Water-free transportation (WFT) causes shrimp (Penaeus vannamei) flesh quality deterioration. However, the roles of endogenous protease-induced protein hydrolysis have been neglected in the research. In the present study, calpain zymography, gelatinase zymography, the hematoxylin–eosin staining method, and other methods were applied to investigate the response of various endogenous proteases (cathepsin, calpain, and gelatinase), the myofibril fragmentation index (MFI), and the microscopic morphology of shrimp muscle during WFT in comparison with the shrimp under the conventional water transportation strategy (WT). The results showed that the total activity of proteases in shrimp muscle increased significantly (p ≤ 0.05) after simulated transportation. Cathepsins and gelatinases were activated during WFT. No significant (p > 0.05) changes of the activity of caspase-3 and the muscle cell apoptosis rate were detected in shrimp muscle cells after WFT. In addition, the MFI increased and the gap among muscle fiber bundles enlarged after WFT. Compared with WFT, no significant (p > 0.05) effect on the activities of calpain, gelatinase, and caspase-3 in the muscle of shrimp was found after WT, and only the activity of cathepsin L significantly increased (p ≤ 0.05). Based on the findings, we concluded that the activation of various endogenous proteases was induced during WFT. [ABSTRACT FROM AUTHOR]

The experiment took the broccoli (Brassica oleracea var. italica) as the research object, 1-methylcyclopropene (1-MCP), mustard essential oil (MEO) and 1-MCP combined MEO (1-MCP+MEO) were used to treat fresh green broccoli. The effects of physiological and biochemical indexes such as sensory quality, relative conductivity, chlorophyll, vitamin C and malondialdehyde (MDA) content on the quality of broccoli were investigated during storage. The result showed that with the increase of storage time, all groups of preservative treatments could effectively maintain the quality of broccoli during storage, among which 1-MCP+MEO treatment had the best storage effect on broccoli, effectively maintained the appearance of broccoli, avoided yellows and mildew, and slowed down the chlorophyll content and vitamin C degradation rate and made the chlorophyll content of broccoli always higher than that of other treatment groups. 1-MCP+MEO inhibited the increase of relative conductivity and MDA content in broccoli. On the 28th day of storage, the relative conductivity and MDA of the combined treatment group were 14.94% and 9.1 µmol/g, respectively, which were 43.1% and 27.6% lower than that of the control group respectively, and there was a significant difference (P<0.05), so that the cell integrity of the broccoli was maintained and the senescence of the broccoli was inhibited. After 28 days of storage, 1-MCP+MEO treatment group could effectively reduce the decrease of total phenol and total flavonoid contents, and combined treatment was 51.9% higher than that of control group, and total flavonoid content was 38.4% higher than that of control group. In addition, the activity of polyphenoloxidase (PPO) and peroxidase (POD) related to enzymatic browning was significantly inhibited, and the activity of PPO and POD were 23.6% and 48.1% lower than that of control group, respectively. Significantly lowered than control group (P<0.05). This study aims to provide a theoretical basis for the development of broccoli preservation technology and a new idea for the research and development of preservatives. [ABSTRACT FROM AUTHOR]

BACKGROUND: Water‐free transportation (WFT), as a novel strategy for express delivery of live shrimp (Litopenaeus vannamei), was developed recently. However, air exposure during this transportation arouses a series of abiotic stress to the shrimp. In the present study, the influences of WFT stress on glycolysis and lipolysis metabolism and meat quality (umami flavor and drip loss) were investigated in comparison with conventional water transportation (WT). RESULTS: The results showed that type II muscle fibers with the feature of anaerobic metabolism were dominated in shrimp flesh. In addition, the increments of intracellular Ca2+ was detected in WFT and WT, which then activated the AMP‐activated protein kinase pathway and promoted the consumption of glycogen, as well as the accumulation of lactate and lipolysis, under the enzymolysis of hexokinase, pyruvate kinase, lactate dehydrogenase and adipose triglyceride lipase. Glycogen glycolyzed to latate. Meanwhile, ATP degraded along with glycolysis resulting in the generation of ATP‐related adenosine phosphates such as inosine monophosphate with umami flavor and phosphoric acid. More remarkable (P < 0.05) physiological changes (except lactate dehydrogenase and lactate) were observed in WFT compared to WT. Additionally, the fatty acid profile also slightly changed. CONCLUSION: The transport stress induced significant energy metabolism changes of shrimp flesh and therefore effected the flesh quality. The intensifications of freshness (K‐value) of shrimp flesh were detected as a result of ATP degradation, which were more pronounced after WFT. However, the drip loss of shrimp flesh was more significantly increased (P < 0.05) after WFT compared to WT. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

A new fermentation method for kiwi wine was explored by developing the well-known medicinal and edible plant Cyclocarya paliurus (C. paliurus) to create more value with undersized kiwifruits. In this study, the changes in bioactive substances during the C. paliurus–kiwi winemaking process were analyzed on the basis of response surface optimization results, and the antioxidant capacity, aromatic compounds, and sensory quality of the C. paliurus–kiwi composite wine with kiwi wine and two commercial kiwi wines were compared. The results showed that DPPH radical, OH− radical, and ABTS+ scavenging rates remained at over 60.0%, 90.0%, and 70.0% in C. paliurus–kiwi wine, respectively. The total flavonoid content (TFC) and total polyphenol content (TPC) of C. paliurus–kiwi wine were significantly higher than those of the other three kiwi wines. C. paliurus–kiwi wine received the highest score and detected 43 volatile compounds. Ethyl hexanoate, which showed stronger fruity and sweet aromas, was one of the main aroma components of C. paliurus–kiwi wine and different from commercial wines. This wine has a good flavor with a natural and quality feeling of C. paliurus–kiwifruit extract, low-cost processing, and great market potential. [ABSTRACT FROM AUTHOR]

Oxidation of lipid and protein is a major reason of flesh quality deterioration during storage. In this work, cold storage (CS) and flake ice (FI) storage, as traditional strategies for live shrimp (Litopenaeus vannamei) sedation and refrigerated storage, showed remarkable oxidation damage of lipid and protein in shrimp flesh during storage. In contrast, ice slurry (IS), with good heat exchange capacity and contactability, stunned shrimp in a sudden and thus relieved antemortem stress, which resulted in reducing the reactive oxygen species and reactive nitrogen species accumulation, and the oxidation damage risk in flesh. Additionally, IS, as a storage medium acted an oxygen barrier, further inhibited the oxidation of lipid and myofibrillar protein (MP), as revealed by the lower thiobarbituric acid reactive substances level, carbonyl (CO) derives content, total disulfide bond (S–S) content, and the higher total sulfhydryl (SH) content in shrimp flesh during storage, compared with CS and FI. The sodium dodecyl sulfate‐polyacrylamide gel electrophoresis electrophoretogram pattern of MP also suggested better preservation of myosin heavy chain, myosin light chain, actin, and tropomyosin in IS, whereas these proteins degraded in CS and FI. Consequently, IS prevented the formation of cross‐linking caused by oxidation in MP, leading to improved shrimp flesh quality during refrigerated storage, as demonstrated by the better maintained hardness, springiness, and water‐holding capacity compared to CS and FI. [ABSTRACT FROM AUTHOR]

BACKGROUND: Boscalid is often used to extend the storage time of postharvest cherry tomato. Pesticide residue has become an issue of food safety. This study sought to investigate the spatial distribution of boscalid residue in cherry tomato fruits and to determine the effect of 24‐epibrassinolide (EBR) in promoting boscalid degradation. RESULTS: Boscalid could quickly penetrate into cherry tomatoes, but mainly remained in the peel. The migration of boscalid from the peel into the core was a time‐consuming and complex process during storage. After 72 h, boscalid residues in the pulp and the core began to accumulate gradually. The exogenous application of EBR activated peroxidase, glutathione reductase and glutathione S‐transferase, and effectively promoted the degradation of boscalid by a maximum decrease of 44.8% in peel, 54.0% in pulp and 71.2% in core. CONCLUSION: As one of the common pesticides, boscalid had a strong ability to enter the cherry tomato and thus become a potential risk for public consumption. Therefore, rational use of pesticides is recommended. The results of this study indicate that the possible risk of boscalid residue could be alleviated by EBR pretreatment through activating detoxification enzymes. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

A new fermentation method for kiwi wine was explored by developing the well-known medicinal and edible plant Cyclocarya paliurus ( C. paliurus ) to create more value with undersized kiwifruits. In this study, the changes in bioactive substances during the C. paliurus -kiwi winemaking process were analyzed on the basis of response surface optimization results, and the antioxidant capacity, aromatic compounds, and sensory quality of the C. paliurus -kiwi composite wine with kiwi wine and two commercial kiwi wines were compared. The results showed that DPPH radical, OH - radical, and ABTS + scavenging rates remained at over 60.0%, 90.0%, and 70.0% in C. paliurus -kiwi wine, respectively. The total flavonoid content (TFC) and total polyphenol content (TPC) of C. paliurus -kiwi wine were significantly higher than those of the other three kiwi wines. C. paliurus-kiwi wine received the highest score and detected 43 volatile compounds. Ethyl hexanoate, which showed stronger fruity and sweet aromas, was one of the main aroma components of C. paliurus -kiwi wine and different from commercial wines. This wine has a good flavor with a natural and quality feeling of C. paliurus -kiwifruit extract, low-cost processing, and great market potential.