Influences of two transport strategies on AMPK-mediated metabolism and flesh quality of shrimp (Litopenaeus vannamei).

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.

Application of Cyclocarya paliurus-Kiwifruit Composite Fermented to Enhance Antioxidant Capacity, Flavor, and Sensory Characteristics of Kiwi Wine.

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.

Impacts of long-time transportation on whiteleg shrimp (Penaeus vannamei) muscle quality and underlying biochemical mechanisms.

BACKGROUND: Shrimp is widely consumed around the world. Since muscle is the primary edible component of shrimp, muscle quality (particularly texture) has a direct impact on the economic value of shrimp products. However, reports on the shrimp muscle quality influenced by transportation are rather limited, and the underlying mechanism remains unknown. RESULTS: During the simulated transportation, the water pH and total ammonia-nitrogen content and un-ionized ammonia contents were elevated. Furthermore, reductions in shrimp muscle water-holding capacity, hardness, and shear value with intensive myofibrillar protein degradation were detected. Simulated transportation decreased the pH and glycogen content of shrimp muscle while increasing lactic dehydrogenase activity and lactate content, resulting in an elevated level of free calcium ions and increased µ-calpain and general proteolytic activities. Water exchange could improve the water quality and reduce the mortality of shrimp during transportation, as well as decrease muscle textural softening by alleviating these stress responses. CONCLUSIONS: Maintaining water quality and, in particular, reducing ammonia are critical to improving shrimp survival and muscle quality during live transportation. This study is of great significance for the better maintenance of the textural properties of shrimp meat. © 2023 Society of Chemical Industry.

Exogenous 24-epibrassinolide activates detoxification enzymes to promote degradation of boscalid in cherry tomatoes.

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.

Thawing of Frozen Hairtail (Trichiurus lepturus) with Graphene Nanoparticles Combined with Radio Frequency: Variations in Protein Aggregation, Structural Characteristics, and Stability.

Efficient thawing can preserve the quality of frozen hairtail (Trichiurus lepturus) close to that of fresh hairtail. In contrast to air thawing (AT) and radio-frequency thawing (RT), this study looked at how graphene oxide (GO) and graphene magnetic (GM) nanoparticles paired with RT affect the microstructure and protein conformation of hairtails after thawing. The results suggested that GM-RT can reduce the myofibrillar protein (MP) damage and be more effective than other thawing treatments, like AT, RT, and GO-RT, in maintaining the microstructure of hairtail. The particle size and zeta potential showed that GM-RT could reduce the aggregation of MP during the thawing process compared to other thawing methods. Moreover, the texture of the hairtail after GM-RT exhibited higher hardness (1185.25 g), elasticity (2.25 mm), and chewiness (5.75 mJ) values compared to other thawing treatments. Especially compared with RT, the GM-RT treatment displayed significant improvements in hardness (27.24%), a considerable increase in springiness (92.23%), and an increase in chewiness (57.96%). GO-RT and GM-RT significantly reduced the centrifugal loss. The scanning electron microscopy results demonstrated that the effect of GM-RT was more akin to that of a fresh sample (FS) and characterized by a well-organized microstructure. In conclusion, GM-RT effectively diminished the MP aggregation and improved the texture of thawed fish. It can be regarded as a viable alternative thawing technique to enhance MP stability, which is vital for preserving meat quality.

The impact of ice slurry as a medium on oxidation status and flesh quality of shrimp (Litopenaeus vannamei) during refrigeration storage.

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.

Xanthine Oxidase Inhibitory Peptides from Larimichthys polyactis: Characterization and In Vitro/In Silico Evidence.

Hyperuricemia is linked to a variety of disorders that can have serious consequences for human health. Peptides that inhibit xanthine oxidase (XO) are expected to be a safe and effective functional ingredient for the treatment or relief of hyperuricemia. The goal of this study was to discover whether papain small yellow croaker hydrolysates (SYCHs) have potent xanthine oxidase inhibitory (XOI) activity. The results showed that compared to the XOI activity of SYCHs (IC50 = 33.40 ± 0.26 mg/mL), peptides with a molecular weight (MW) of less than 3 kDa (UF-3) after ultrafiltration (UF) had stronger XOI activity, which was reduced to IC50 = 25.87 ± 0.16 mg/mL (p < 0.05). Two peptides were identified from UF-3 using nano-high-performance liquid chromatography-tandem mass spectrometry. These two peptides were chemically synthesized and tested for XOI activity in vitro. Trp-Asp-Asp-Met-Glu-Lys-Ile-Trp (WDDMEKIW) (p < 0.05) had the stronger XOI activity (IC50 = 3.16 ± 0.03 mM). The XOI activity IC50 of the other peptide, Ala-Pro-Pro-Glu-Arg-Lys-Tyr-Ser-Val-Trp (APPERKYSVW), was 5.86 ± 0.02 mM. According to amino acid sequence results, the peptides contained at least 50% hydrophobic amino acids, which might be responsible for reducing xanthine oxidase (XO) catalytic activity. Furthermore, the inhibition of the peptides (WDDMEKIW and APPERKYSVW) against XO may depend on their binding to the XO active site. According to molecular docking, certain peptides made from small yellow croaker proteins were able to bind to the XO active site through hydrogen bonds and hydrophobic interactions. The results of this work illuminate SYCHs as a promising functional candidate for the prevention of hyperuricemia.

Microencapsulation of tomato seed oil using phlorotannins-adducted pea protein isolate-chitosan and pea protein isolate-chitosan complex coacervates.

Pea protein isolates (PPI)/phlorotannins (PT)/chitosan (CS) ternary complex and PPI/CS binary complex were synthesized to prepare tomato seed oil (TSO) microcapsules. The concentration of PT was determined to be 0.025% (w/w) based on the solubility, emulsification, and UV-visible spectrum of PPI-PT complex. Subsequently, the optimal pHs associated with the formation of PPI/CS and PPI-PT/CS complex coacervates were determined to be pH 6.6 and 6.1, while the optimal ratios were 9:1 and 6:1, respectively. The coacervate microcapsules were successfully produced by freeze-dried method and those formulated with PPI-PT/CS displayed significantly lower surface oil content (14.57 ± 0.22%), higher encapsulation efficiency (70.54 ± 0.13%), lower particle size (5.97 ± 0.16 µm), and PDI (0.25 ± 0.02) than PPI/CS. The microcapsules were characterized by scanning electron microscopy and Fourier Transform infrared spectroscopy. Furthermore, the encapsulated TSO exhibited enhanced thermal and oxidative stability than that of free oil, along with microcapsules fabricated with PPI-PT/CS ternary complex showed better protection than that of free PT. Overall, PPI-PT/CS complex as an effective wall material in delivery system presented great potential.

Abscisic acid stimulates wound suberisation in kiwifruit (Actinidia chinensis) by regulating the production of jasmonic acid, cytokinin and auxin.

Wounding induces a cascade of correlative physiological responses that lead to the repair of damaged tissue. In this study, the effect of wounding on suberin, endogenous hormones and their metabolic genes expression was observed during the wound healing of kiwifruit (Actinidia chinensis Planch.). In addition, the role of abscisic acid (ABA) in wound suberisation was investigated by analysing the coordinated regulation between ABA and other hormones. The wound healing process in kiwifruit could be divided into two stages including: (1) initial accumulation of suberin polyphenolic (SPP) and long carbon chain suberin polyaliphatic monomers (LSPA) before 24h; and (2) massive synthesis of SPP and very long carbon chain suberin polyaliphatic monomers (VLSPA) after 24h. ABA content rapidly increased and induced the jasmonic acid (JA) biosynthesis at the early stage of wound healing. ABA level gradually decreased with the expression of AchCYP707A genes, while the contents of trans-zeatin (t-ZT) and indole-3-acetic acid (IAA) steadily increased at the late stage of wound healing. Exogenous ABA stimulated JA and suberin monomers accumulation, but suppressed both t-ZT and IAA biosynthesis. The role of ABA in wound healing of kiwifruit might be involved in the coordination of both JA-mediated suberin monomers biosynthesis and t-ZT- and IAA-mediated formation of suberised cells via an interaction mechanism.

Heat shock protein 70 (HSP70) promotes air exposure tolerance of Litopenaeus vannamei by preventing hemocyte apoptosis.

Brief pretreatment of cold shock at 13 °C for 3 min proved to be an inducer of heat shock protein 70 (HSP70) and improved stress tolerance as a molecular chaperone. With the improvement of air exposure tolerance, HSP70 in shrimp hemocytes was upregulated in mRNA and protein levels after cold shock. Both HSP70 RNA interference (RNAi) gene knockdown and recombinant HSP70 (rHSP70) injection were successfully established in order to investigate the role of HSP70 in response to air exposure stress. Shrimp receiving rHSP70 showed an improved survival rate (80%) with no significant difference (p > 0.05) compared to cold shock treated shrimp (control, 90%) under air exposure, but the survival rate of HSP70-knockdown shrimp was significantly lower (62%, p < 0.05). Reactive oxygen species (ROS) content, relative expression of cytochrome c, caspase-3 activity, and apoptosis rate in hemocytes of HSP70 enriched shrimp (i.e., cold shock and rHSP70 injection) were significantly lower (p < 0.05) than HSP70-knockdown shrimp. Results suggested that HSP70 could be induced by cold shock and contributed to improve the tolerance of shrimp suffering air exposure by blocking the apoptosis pathway through scavenging intracellular ROS, inhibiting cytochrome c expression, inhibiting release from mitochondria, and inactivating caspase-3. This work updates the understanding of cold shock mechanism in water-free transportation of aquatic animals.

Preparation and physicochemical stability of tomato seed oil microemulsions.

In this study, microemulsions were fabricated using tomato seed oil, water, Tween 80 and citric acid, and then the physicochemical characteristics and the influence of environmental stress were investigated. The physicochemical properties of the microemulsions were evaluated by transmission electron microscopy (TEM), mean particle diameter, polydispersity index (PDI) and conductivity. The phase diagrams of tomato seed oil/Tween 80/citric acid/water microemulsions were constructed under different pHs and ionic strengths. Storage stability of the systems was investigated at 4, 37 and 65°C, and changes in turbidity and lipid oxidation products were monitored. Nano-size zeta potential analyzer results demonstrated that the mean particle diameter and polydispersity index of tomato seed oil microemulsions were 14 nm and 0.014. The transition from W/O to O/W could be detected from electrical conductivity and viscosity data with the increasing of water content. The results showed that the microemulsion areas decreased with increasing pH and NaCl concentrations. What is more, the study proved that tomato seed oil microemulsions exhibited a good storage stability. PRACTICAL APPLICATION: In this study, the preparation of tomato seed oil microemulsion can not only make full use of the nutritional value of tomato seed oil, but also ensure the effective protection of the nutrients contained in it, and improve the problem of adding difficult. By using microemulsion as delivery carrier of tomato seed oil, the application of tomato seed oil in food, cosmetics and other fields could be enhanced. Therefore, the preparation of tomato seed oil microemulsion provides a theoretical basis for production practice.

Physicochemical and structural properties of low-amylose Chinese yam (Dioscorea opposita Thunb.) starches.

Nuoshanyao (NSY), Tiegunshanyao (TSY) and Huaishanyao (HSY) are the main cultivars of Chinese yam (Dioscorea opposita Thunb.) widely grown in China. The composition, physicochemical properties, morphology, and thermal properties of the starches from these cultivars were investigated in this study. NSY starch (17.0%) was much lower in amylose content than other cultivars (33.4-34.5%). The average particle diameter of the starches ranged from 25.83 to 28.93 µm. Weight-average molecular weights (Mw) and number-average molecular weights (Mn) ranged from 1.29 to 1.84 × 105 g/mol and 5.93 to 8.36 × 104 g/mol, respectively. NSY starch had higher gelatinization temperature (71.5 °C), enthalpy (14.14 J/g), peak viscosity (8590 cP) and swelling power (12.0%) than TSY and HSY. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) tests indicated that Chinese yam starches had CB-type crystalline structure with crystallinity ranging from 21.91% to 27.08% and a short-range ordered structure. To, Tp, ΔH, peak viscosity and swelling power at 95 °C were significantly correlated to amylose content. The low-amylose NSY starch was found to have high gelatinization temperature, enthalpy, peak viscosity and swelling power. These specific physicochemical and structural properties indicated the industrial potential of low-amylose yam starch.

Evaluation of immunological response in shrimp Penaeus vannamei submitted to low temperature and air exposure.

The objective of this study is to explore the immune response of the shrimp Penaeus vannamei to low temperature and air exposure during the mimic waterless transportation. Shrimp were cold shocked at 13 °C for 3 min, then exposed to air at 15 °C for 12 h, and finally revived in water at 25 °C. Hemocyte structure remained intact with only slight distortions of some organelles and nuclear membrane under the stress. Phenoloxidase (PO), lysozyme (Lys) and gamma-glutamyl transferase (GGT) activities, glutamine (Gln) content and relative mRNA expressions of prophenoloxidase (proPO), ß-1,3-glucan binding protein (LGBP), ferrin (Fer) and glucose regulated protein 78 (GRP 78) increased and reached peak levels after 3 h-9 h of air exposure, and then decreased to relatively stable levels in the prolonged period of air exposure. The total hemocyte count (THC) and gene expressions of proPO, Fer and LGBP at the end of waterless storage were significantly lower (p < 0.05) than those in fresh shrimp while no significant difference (p ≥ 0.05) was found between revived and fresh shrimp in PO, Lys, GGT activities, Gln content and gene expression level of GRP 78. Of all the hemocytes, the percentage of semi granular cells (SGC) and granular cells (GC) significantly decreased after 6-9 h of storage, while hyaline cells (HC) dramatically increased after 9 h of storage to compensate the loss of SGC and GC. Results suggested that the low temperature and air exposure caused significant immunological response to the shrimp, but the damages to the immune system were partly reparable.

Three Transcription Activators of ABA Signaling Positively Regulate Suberin Monomer Synthesis by Activating Cytochrome P450 CYP86A1 in Kiwifruit.

Wound attack stimulates accumulation of abscisic acid (ABA) that activates a number of genes associated with wound suberization of plants. Cytochrome P450 fatty acid ω-hydroxylase CYP86A1 catalyzes ω-hydroxylation of fatty acids to form the ω-functionalized monomers that play a pivotal role in suberin synthesis. However, the transcriptional regulation of ABA signaling on AchnCYP86A1 has not been characterized in kiwifruit. In this study, AchnCYP86A1, a kiwifruit homolog of Arabidopsis AtCYP86A1, was isolated. AchnCYP86A1-overexpressed N. benthamiana leaves displayed that the AchnCYP86A1 functioned as a fatty acid ω-hydroxylase associated with synthesis of suberin monomer. The regulatory function of three transcription factors (TFs, including AchnMYC2, AchnMYB41 and AchnMYB107) on AchnCYP86A1 was identified. All the three TFs were localized in nucleus and could individually interact with AchnCYP86A1 promoter to activate gene expression in yeast one-hybrid and dual-luciferase assays. The findings were further demonstrated in transient overexpressed N. benthamiana, in which all TFs notably elevated the expression of aliphatic synthesis genes including CYP86A1 and the accumulation of ω-hydroxyacids, α, ω-diacids, fatty acids and primary alcohols. Moreover, exogenous ABA induced the expression of AchnMYC2, AchnMYB41 and AchnMYB107 that promoted AchnCYP86A1 involving in suberin monomer formation. Contrary to the inductive effects of ABA, however, fluridone (an inhibitor of ABA biosynthesis) inhibited the three TFs expression and suberin monomer formation. These results indicate that AchnMYC2, AchnMYB41 and AchnMYB107 positively regulate suberin monomer synthesis by activating AchnCYP86A1 promoter in response to ABA.

Cooling combined with hyperoxic CO2 anesthesia is effective in improving the air exposure duration of tilapia.

Tilapia were subjected to cooling (CO, a stepwise reduction in temperature from 30 °C to 15 °C), anesthesia (AN, anesthetized by hyperoxic carbon dioxide), air exposure (AE, exposed to air) and cold tolerance (CT, in 15 °C water) treatments, and the physiological responses were determined after the treatments. CO followed by AN treatment for tilapia could meet the criteria of an ideal anesthetic. Fish were deeply sedated within 69 s, completely anesthetized within 276 s and recovered within 308 s without any mortality. The stress responses induced by the CO&AN treatment were mild, whereas they were consistently increased in the AE treatment. Furthermore, the AE treatment caused tissue damage. The AE duration was significantly improved by CO&AN treatment, and the survival time of the CO&AE, AN&AE and CO&AN&AE treatments were 313 min, 351 min and 561 min, respectively, in the laboratory experiments, whereas the survival rate of the CO&AN&AE treatment group after 240-min air exposure was 95.2% in the pilot test. It appeared that cooling followed by hyperoxic CO2 anesthesia would be suitable for handling tilapia in a short-time air exposure procedure.