Effect of Washing Times on the Quality Characteristics and Protein Oxidation of Silver Carp Surimi

Intermolecular interactions influenced the gelation and texture improvement of sturgeon surimi gels by walnut protein isolates

Intermolecular interaction is a key factor in the fortification of surimi gels by plant protein addition. Here, the effects of different intermolecular interactions, such as ionic, covalent and non-covalent interactions, on gel structure, gelation strength and water-holding properties were investigated, using sturgeon surimi fortified by three walnut isolates, including walnut meal (WM), protein isolate (WPI) and peptide (WP), as representatives. Quantitative creep-recovery analysis and soluble protein assay demonstrated that secondary bonds, mainly hydrophobic interaction and hydrogen bond, possibly played a dominant role in walnut protein-fortified surimi gels. Hydrophobic interaction and disulfide bond benefited gelation behavior and textural strengthening by supplementation of WM and WPI. However, 1-3 % addition of WPI and WP positively influenced water retention of surimi gels due to higher hydrogen bonding level. Structural integrity of surimi gel was not destroyed, while appropriate addition of walnut proteins especially WPI improved sensory quality of sturgeon surimi product.

Soybean protein isolate-inulin conjugates prepared through ultrasound improves the quality of unwashed surimi gel

In order to improve the problem of low quality in unwashed surimi gels, this study prepared soybean protein isolate-inulin (SPI-inulin) conjugates using ultrasonic-assisted treatment and investigated their potential applications in unwashed surimi. The results demonstrated that sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fourier transform infrared analysis confirmed the formation of SPI-inulin conjugates. The addition of inulin loosened the structure of SPI. Compared to the unwashed surimi control, the addition of SPI-inulin conjugates significantly improved gel strength, water holding capacity and texture properties (P < 0.05), reduced the free water molecules in the gel matrix, and effectively filled the pores of the surimi gel network when 0.8 % SPI-inulin conjugates were added. In conclusion, the addition of SPI-inulin conjugates represented an effective strategy to enhance the performance of unwashed surimi gels, providing a novel approach for the development of new types of unwashed surimi.

Effect and mechanisms of mechanical pre-dehydration treatment on gelling and physicochemical properties of unwashed silver carp (Hypophthalmichthys molitrix) surimi

Washing improves the overall quality of surimi production. However, the washing process significantly increases wastewater discharge from factories, thus raising environmental concerns and highlighting the need for more sustainable methods of surimi production. This study aimed to investigate the possibility of improving the quality of unwashed freshwater surimi by mechanical pre-dehydration and to explore the changes in gelling properties and physicochemical characteristics during frozen storage. The results indicate that the gel strength and water-holding capacity (WHC) of mechanically pre-dehydrated unwashed surimi can reach 522.50 g·cm and 68.12 %, which were equivalent to surimi subjected to two washes. During frozen storage, the pre-dehydration exhibited beneficial effects on the gel properties and water retention of surimi. Furthermore, SDS-PAGE analysis indicated that pre-dehydration retarded protein degradation during frozen storage. Indicators such as sulfhydryl groups, carbonyl content, protein solubility, and TBARS indicated that pre-dehydration could reduce the rate of protein and lipid oxidation. Focusing on the changes in endogenous components during the pre-dehydration, we showed that the dehydration could reduce the fat content (from 83.8 g/kg to 68.03 g/kg) and activities of cathepsin B (from 13.1 U/g to 7.3 U/g), lipoxygenase (from 621.3 U/g to 416 U/g), and gelatin-degrading enzymes in unwashed surimi, thereby enhancing the gel properties and frozen stability. Therefore, mechanical pre-dehydration can enhance the quality of unwashed surimi, thus providing a more environmentally friendly surimi production method.

Effect of magnetic field-assisted thawing on the quality and microstructure of Portunus trituberculatus meat

The objective of this study was to examine the impact of magnetic field-assisted thawing (MFT) on the quality and microstructure of Portunus trituberculatus meat, in comparison to other thawing methods (Air thawing, AT; Hydrostatic thawing, HT; Microwave thawing, MT). A comprehensive comparative analysis was conducted on different physicochemical and flavor properties of crab meat. MFT significantly reduced thawing loss by 18.9-20.0 % and TBARS levels by 40 % compared to the other methods, demonstrating its ability to minimize lipid oxidation. Microstructure analysis showed that MFT preserved muscle fiber integrity, leading to a denser and more organized structure with reduced protein denaturation. This performance was attributed to MFT's ability to reduce protein denaturation, which effectively minimizes water loss and inhibits lipid oxidation during thawing. Moreover, MFT improved the retention of key flavor compounds, increasing nonanal and 2-undecanone levels by 31.4 % and 69 %, respectively, contributing to a fresher aroma. MFT group also retained more umami (Glu + 40.8 %) and sweet amino acids (Gly, Ala + about 19.8 %), and nucleotides (AMP + 0.8 %, IMP + 9.4 %), while less bitter amino acids (Lys -68.2 %, Met -51.9 %). In conclusion, MFT had good ability of keeping quality of crabs meat, providing noval thawing method for P. trituberculatus.

Fish oil-loaded silver carp scale gelatin-stabilized emulsions with vitamins for the delivery of curcumin

The encapsulation of curcumin in the emulsions has attracted much attention in functional food development. Herein, the fish oil-loaded silver carp scale gelatin-stabilized emulsions with vitamins were explored for the delivery of curcumin. The curcumin encapsulation had no obvious effect on the formation, storage stability, lipid oxidation, and in vitro droplet digestion behaviors of the emulsions. Both vitamin C (VC) and vitamin E (VE) additions had obvious effects on the peroxidation values of the emulsions: VC + VE < VC < VE < Control < fish oil. The accumulative free fatty acid release percentages were dependent on the vitamins: VC (89.6 ± 1.1%) > Control (86.1 ± 1.0%) > VC + VE (80.5 ± 0.8%) > VE (76.4 ± 1.2%). The emulsions' curcumin retention at room temperature and in vitro digestion behaviors (transformation, bioaccessibility, and bioaccessibility index) depended on vitamin additions: VC + VE ≈ VC > VE ≈ Control. This work was beneficial for the development of fish gelatin-stabilized emulsions to deliver curcumin.

Recovery of protein-rich biomass from surimi rinsing wastewater by using a sustainable cold plasma treatment

Surimi rinsing wastewater is typically discarded, causing waste of protein resources and environmental pollution. This study investigated the technology of a cold atmospheric plasma jet (CAPJ) for the recovery of protein-rich biomass (PRB), including myofibrillar proteins (MPs) and sarcoplasmic proteins (SPs), from surimi rinsing wastewater. The protein recovery yield was up to 59.84 %. CAPJ induced an increase in carbonyl and decreased sulfhydryl in protein content. Furthermore, the secondary structure of the protein was unfolded, particularly the transition from α-helix to β-sheet. The formation of disulfide bonds and increased hydrophobic interactions promoted protein aggregation (the particle size from 185.76 nm to 1869.07 nm, P < 0.05) and reduced solubility. The proteomic results indicated that CAPJ increased the expression level of antioxidant enzymes. Overall, the CAPJ technology could recover proteins from surimi rinsing wastewater for industrial application, which will promote the sustainable development of the surimi industry.

Quality and flavor development of solid-state fermented surimi with Actinomucor elegans: A perspective on the impacts of carbon and nitrogen sources

The influence of four carbon and nitrogen substrates on the quality and flavor of a novel surimi-based product fermented with Actinomucor elegans (A. elegans) was investigated, with a focus on carbon and nitrogen catabolite repression. The results showed that the substrate significantly affected mycelial growth, enzyme activities, and the metabolites of A. elegans. Although glucose significantly promoted A. elegans growth by 116.69%, it decreased enzyme secretion by 69.79% for α-amylase and 59.80% for protease, most likely by triggering the carbon catabolite repression pathway. Starch, soy protein, and wheat gluten substantially affected the textural properties of the fermented surimi. Furthermore, wheat gluten significantly promoted the protease activity (102.70%) and increased protein degradation during surimi fermentation. The fishy odor of surimi was alleviated through fermentation, and a correlation between the volatile compounds and A. elegans metabolism was observed. These results explore fermentation substrates in filamentous fungi metabolism from a catabolite repression perspective.

Codonopsis radix: a review of resource utilisation, postharvest processing, quality assessment, and its polysaccharide composition

Codonopsis radix is the dried root of C. pilosula (Franch.) Nannf., C. pilosula Nannf. var. modesta (Nannf.) L. T. Shen, or C. tangshen Oliv., constitutes a botanical medicine with a profound historical lineage. It encompasses an array of bioactive constituents, including polyacetylenes, phenylpropanoids, alkaloids, triterpenoids, and polysaccharides, conferring upon it substantial medicinal and edible values. Consequently, it has garnered widespread attention from numerous scholars. In recent years, driven by advancements in modern traditional Chinese medicine, considerable strides have been taken in exploring resources utilization, traditional processing, quality evaluation and polysaccharide research of Codonopsis radix. However, there is a lack of systematic and comprehensive reporting on these research results. This paper provides a summary of recent advances in Codonopsis research, identifies existing issues in Codonopsis studies, and offers insights into future research directions. The aim is to provide insights and literature support for forthcoming investigations into Codonopsis.

Study on the Quality Variation and Internal Mechanisms of Frozen Oatmeal Cooked Noodles during Freeze-Thaw Cycles

Frozen staple food, attributed to its favorable taste and convenience, has a promising development potential in the future. Frequent freezing and thawing, however, will affect its quality. This study simulated several freeze-thaw cycles (FTC) that may occur during the cold chain process of frozen oatmeal cooked noodles (FOCN) production to consumption. The quality changes and their mechanisms were elucidated using methods such as differential scanning calorimetry (DSC), low-field nuclear magnetic resonance (LF-NMR), Fourier-transform infrared spectroscopy (FTIR), confocal laser scanning microscopy (CLSM), texture analysis, and sensory evaluation. The freezable water content of the FOCN decreased because of the FTC treatment, and the relative content of total water in FOCN also decreased accordingly. The increase in β-Turn after FTC induced disorder in the secondary structure of proteins, causing the protein microstructure to become loose and discontinuous, which in turn reduced the water-holding capacity of FOCN. Additionally, FTC reduced the chewiness and sensory score of FOCN. This research will contribute a theoretical foundation for optimizing the cold chain process.

Processing and Preservation of Aquatic Products

Aquatic products represent an important food source; they include products such as fish, shrimp, shellfish, crab, and seaweed, and provide high-quality proteins, fatty acids, minerals, and other nutritional elements [...].

Investigation of the effect of chemical composition of surimi and gelling temperature on the odor characteristics of surimi products based on gas chromatography-mass spectrometry/olfactometry

This study investigated the effects of chemical composition of surimi (prepared by 0, 1, or 2 times of rinsing) and gelling temperature (90 °C and 100 °C) on the odor characteristics of surimi products and the relationship between the chemical composition of surimi and the aroma of surimi products. The once- and twice-rinsed surimi showed a decrease (p < 0.05) of 71.32%, 74.60%, 42.79% and 61.12% in the contents of total amino acids and total fatty acids, respectively. The surimi products prepared with un-rinsed surimi at 90 °C had the highest fish-fragrance score, while those prepared with once-rinsed surimi at 100 °C showed the strongest warmed-over flavor (WOF) and the lowest fish-fragrance score.Gly, Phe, and most of the saturated fatty acids were associated with WOF formation in surimi products, while Leu, Ile, Val, Asp, and unsaturated fatty acids were positively related to their fish-fragrance note.