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•Ultrasound combined with SPI enhanced the hardness and strength of low-salt surimi gel.•Ultrasonic and SPI enhanced the WHC of the gel, and quicker the T2b, T21 and T22.•Ultrasound ...and SPI improved salt-soluble protein content and transform α-helix to β-sheet.•The gel had tighter and smaller pores of ultrasound combined with SPI.
The effects of ultrasound combined (25 kHz, 400 ± 20 W/L, ultrasonic time of 5, 10 and 15 min) with soy protein isolate processing on gelling properties of low-salt silver carp surimi, aggregation and conformation of myofibrillar protein were investigated. The results revealed that, compared with only adding soy protein isolate components, ultrasound-assisted soy protein isolate had a more obvious effect on the protein structure in low-salt surimi, leading to the decrease in α-helix and total sulfhydryl contents, and the increase in β-sheet content and protein solubility. As a result, more proteins participated in the formation of the gel network, and significant improvements in hardness, gel strength and water-holding capacity of the low-salt surimi gel were observed, while the myosin heavy chain in SDS-PAGE was weakened. The low-field NMR results showed that the initial relaxation time of T2 was apparently shorter, the free water content decreased and the bound water content increased under the action of ultrasound. Scanning electron microscope observation found that the surimi gel treated by ultrasound exhibited smaller holes, and had a more stable and denser network structure. In conclusion, the results of our work demonstrated that ultrasound combined with soy protein isolate can significantly improve the gel quality properties of low-salt silver carp.
(loach) is a widely distributed benthic fish in Asia. In this study, the alkaline protease was used to hydrolyze loach, and the hydrolysate products of different molecular weights were obtained by ...membrane separation. In vitro antioxidant assays showed that the <3 kDa fraction (SLH-1) exhibited the strongest antioxidant activity (DPPH, hydroxyl radical and superoxide radical scavenging ability, and reducing power), while SLH-1 was purified by gel filtration chromatography, and peptide sequences were identified by LC-MS/MS. A total of six peptides with antioxidant activity were identified, namely SERDPSNIKWGDAGAQ (D-1), TVDGPSGKLWR (D-2), NDHFVKL (D-3), AFRVPTP (D-4), DAGAGIAL (D-5), and VSVVDLTVR (D-6). In vitro angiotensin-converting enzyme (ACE) inhibition assay and pancreatic cholesterol esterase (CE) inhibition assay, peptide D-4 (IC50 95.07 μg/mL, 0.12 mM) and D-2 inhibited ACE, and peptide D-2 (IC50 3.19 mg/mL, 2.62 mM), D-3, and D-6 acted as pancreatic CE inhibitors. The inhibitory mechanisms of these peptides were investigated by molecular docking. The results showed that the peptides acted by binding to the key amino acids of the catalytic domain of enzymes. These results could provide the basis for the nutritional value and promote the type of healthy products from hydrolyzed loach.
As a traditional Chinese rice wine, Hong Qu glutinous rice wine (HQW) is popular among consumers due to its unique flavor. However, its quality changes during fermentation, and the potential ...relationships between flavor and microbes have not been systematically researched. In this work, physicochemical properties (pH, total sugar, alcohol, amino acid nitrogen), flavor compounds (organic acids, free amino acids, and volatile compounds), and microbial communities were investigated. The results revealed that
,
,
,
, and
predominated the bacterial genera, and
was the predominant fungal genus. Organic acids, free amino acids, and key volatile compounds (esters and alcohols) significantly increased during fermentation. The correlations analysis showed that
was closely associated with flavor compounds formation. This study deepens our understanding of the roles of microorganisms in flavor formation on traditional HQW fermentation.
•
Fermentation decreased pH and Aw and increased ANN, TBARS, TVB-N, and BAs in grass carp flesh.
•
Fermentation with
Lactobacillus plantarum
and flavourzyme could improve physicochemical properties ...of fermented grass carp.
•
Fermentation of
Lactobacillus plantarum
and flavourzyme could contribute to fermented grass carp with safety properties.
The present study aimed to investigate the change in physicochemical and safety properties of grass carp during fermentation with flavourzyme and
Lactobacillus plantarum
(FLF). The natural fermentation (NF) and fermentation with
Lactobacillus plantarum
(LF) samples were used as control. The results showed that with increasing fermentation time, the pH and water activity (Aw) in each fermented grass carp sample gradually decreased, while the a-amino nitrogen (ANN), thiobarbituric acid reactive substance (TBARS), total volatile base nitrogen (TVB-N), biogenic amines (BAs), and harmful microbial gradually increased. Besides, compared with NF samples at each fermentation time, significantly lower pH, Aw, TBARS, TVB-N, BAs, and harmful microbial presented in LF and FLF samples. However, FLF samples have a higher AAN content than that of NF and LF samples during fermentation. Overall, the fermentation with
Lactobacillus plantarum
and flavourzyme could contribute to fermented grass carp products with better physicochemical and safety properties.
Antarctic krill tropomyosin (AkTM) has been shown in mice to cause IgE-mediated food allergy. The objective of this work was to investigate the role of Notch signaling in AkTM-sensitized mice, as ...well as to determine the changes in gut microbiota composition and short-chain fatty acids (SCFAs) in the allergic mice. An AkTM-induced food allergy mouse model was built and
-
-(3,5-difluorophenacetyl)-
-alanyl-
-phenylglycine t-butyl ester (DAPT) was used as an γ-secretase inhibitor to inhibit the activation of Notch signaling. Food allergy indices, some key transcription factors, histologic alterations in the small intestine, and changes in gut microbiota composition were examined. The results showed that DAPT inhibited Notch signaling, which reduced AkTM-specific IgE, suppressed mast cell degranulation, decreased IL-4 but increased IFN-γ production, and alleviated allergic symptoms. Quantitative real-time PCR and Western blotting analyses revealed that expressions of Hes-1, Gata3, and IL-4 were down-regulated after DAPT treatment, accompanied by increases in T-bet and IFN-γ, indicating that Notch signaling was active in AkTM-sensitized mice and blocking it could reverse the Th1/Th2 imbalance. Expressions of key transcription factors revealed that Notch signaling could promote Th2 cell differentiation in sensitized mice. Furthermore, 16S rRNA sequencing results revealed that AkTM could alter the diversity and composition of gut microbiota in mice, leading to increases in inflammation-inducing bacteria such as
and
. Correlation analysis indicated that reduced SCFA concentrations in AkTM-allergic mice may be related to decreases in certain SCFA-producing bacteria, such as
. The changes in gut microbiota and SCFAs could be partially restored by DAPT treatment. Our findings showed that inhibiting Notch signaling could alleviate AkTM-induced food allergy by correcting Th1/Th2 imbalance and modulating the gut microbiota.
Being a natural active substance with a wide variety of sources, easy access, significant curative effect, and high safety, active peptides have gradually become one of the new research directions in ...food, medicine, agriculture, and other fields in recent years. The technology associated with active peptides is constantly evolving. There are obvious difficulties in the preservation, delivery, and slow release of exposed peptides. Microencapsulation technology can effectively solve these difficulties and improve the utilization rate of active peptides. In this paper, the commonly used materials for embedding active peptides (natural polymer materials, modified polymer materials, and synthetic polymer materials) and embedding technologies are reviewed, with emphasis on four new technologies (microfluidics, microjets, layer-by-layer self-assembly, and yeast cells). Compared with natural materials, modified materials and synthetic polymer materials show higher embedding rates and mechanical strength. The new technology improves the preparation efficiency and embedding rate of microencapsulated peptides and makes the microencapsulated particle size tend to be controllable. In addition, the current application of peptide microcapsules in different fields was also introduced. Selecting active peptides with different functions, using appropriate materials and efficient preparation technology to achieve targeted delivery and slow release of active peptides in the application system, will become the focus of future research.
To achieve a krill meal of high quality, a two-stage drying involving hot-air drying and vacuum drying was investigated. Five experimental groups were established according to the different drying ...conditions in the second stage, including 95 °C and 101 kPa, 95 °C and 60 kPa, 75 °C and 101 kPa, 75 °C and 60 kPa, and 75 °C and 20 kPa. The results showed that reducing the drying temperature and vacuum pressure in the second stage had a significant impact on the drying characteristics, sensory quality, and bioactive compounds of krill meal. Among all five groups, the drying condition of 75 °C and 60 kPa maintained a high drying rate while preserving a phospholipid content of 30.01 mg/kg and an astaxanthin content of 37.41 mg/kg. It also effectively reduced the isomerization of astaxanthin and the oxidation of unsaturated fatty acids. These results suggested that the two-stage drying method may contribute to the production of high-quality krill meal.
Fermented vegetable products play a significant role in various cuisines, and understanding the fermentation dynamics of lactic acid bacteria (LAB) strains is essential for optimizing their ...production and quality. Here, we sought to investigate the fermentation performance of five LAB strains isolated from Sichuan paocai as starters for paocai. Sensory evaluation revealed that the inoculation of radish paocai samples with LAB strains effectively improved the overall liking and sensory satisfaction of participants, increasing the scores to varying degrees in terms of taste, flavor, texture, and coloration. Lactiplantibacillus plantarum and Lacticaseibacillus rhamnosus exhibited a good salt resistance in radish juice and could grow in a medium containing 10% NaCl. Four indicator strains commonly found in contaminated paocai were effectively inhibited by fermented LAB broths, which improved the edibility and safe production of paocai. Compared to spontaneous fermentation (CK), radish paocai inoculated with LAB showed a significantly accelerated acid production rate, shortening the fermentation period by approximately two days. The contents of titratable total acids, organic acids, and free amino acids were higher in the inoculated samples and were enriched in the taste of radish paocai. The content of volatile organic compounds in the inoculated samples was higher than that in CK. Based on OPLS-DA analysis, 31 key indicators of paocai quality were screened and used to rank the fermentation performances of the five strains using the TOPSIS method; here, Lpb. plantarum and Lcb. rhamnosus achieved the highest scores. This study provides a reference for selecting LAB strains as efficient and secure fermentation starters to optimize paocai quality.
The active dominant spoilage organisms in the farmed Pseudosciaena crocea would cause short shelf life. This study focused on an identification of spoilage bacteria and the development of predictive ...model of shelf life in Pseudosciaena crocea both fresh and lightly salted during the storage at low, ambient and fluctuating temperature conditions. Microbiological, chemical changes in Pseudosciaena crocea were assessed to ensure the shelf life; Phenotypic and 16S rRNA were used to identified dominated strains from different conditions. Shelf life, remaining shelf life were predicted by predictive models including exponential, school-field and Square-root equation. The results showed that Shewanella spp. was the dominant organism at low temperature, while Vibrio spp. and Enterobacter were the dominant organisms at ambient and fluctuating temperatures.While the Proteus vulgaris, Vibrio alginolytica and serratia were the dominant group at low, ambient and fluctuating environment of the lightly salted Pseudosciaena crocea .The shelf-life of fresh Pseudosciaena crocea were 5.4 ~ 17.8 days, 1.1days and 4.6~9.3 days under low, ambient and fluctuating temperature; while the shelf life of lightly salted Pseudosciaena crocea were 12.2~49.1days, 4.2day and 20.5~23.5 days under low, ambient and fluctuating temperature. The evaluation index showed that School-field model and Exponential model in fresh fish were better, Exponential model was better to predict the shelf life in lightly salted fish. The results can facilitated the establishment of spoilage bacterial Hazard Analysis Critical Control Point during the processing of the Pseudosciaena crocea products.
To investigate the cryoprotective effect of flammulina velutipes polysaccharide (FVP) on the quality characteristics in freeze‐thawed cultured large yellow croaker, 0.050%, 0.075%, and 0.100% FVP was ...used before freezing and the quality after thawing was compared with water soaking (WS) and commercial cryoprotectant (CC) treatment. Quality attributes were comprehensively determined instrumentally and organoleptically after thawing at 4°C. Results showed that FVP effectively reduces the quality deterioration of body color and water‐holding capacity, while no obvious effects were observed in texture and flavor. As for body color, both FVP and CC treatment could maintain the b* value to a large extent. Among them, 0.075% FVP shows the highest value in two sample points, with 55.2% and 21.0% increases seen in the values in WS. FVP‐dose‐dependent trends were found in water‐holding capacity, where a reduction of 28.26% and 14.38% in thawing loss and cooking loss was observed in the 0.100% FVP group. Low‐field nuclear magnetic resonance (LF‐NMR) also revealed that immobilized water and free water were more tightly retained in the muscle tissue with FVP addition. The results of the sensory evaluation are essentially in line with the above observations. These findings indicate that FVP has the potential to partially replace commercial cryoprotectants in aquatic products during frozen storage.
Our project aims to reveal the cryoprotective effect of flammulina velutipes polysaccharide (FVP) on the quality characteristics in freeze‐thawed cultured large yellow croaker. The differences were compared with conventional commercial cryoprotectant in combination with muscle quality, body color, and flavor. From the point of delaying the deterioration of frozen aquatic products’ quality, we believe that this paper is important for extending the shelf life of frozen aquatic products, and for further development of novel aquatic cryoprotectant.
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