This study evaluated the effects of low-molecular-mass chitosan oligosaccharides (COS) on the microbiota and quality of silver carp fillets stored at 4 ℃. The fish fillets were divided randomly into two groups: control and 0.5 g/100 mL COS treatment. To evaluate the preservative effect of COS, sensory scores, total viable count (TVC), total volatile basic nitrogen (TVB-N) content, adenosine triphosphate (ATP)-related compounds and K value were determined and Illumina MiSeq high-throughput sequencing was applied to analyze the microbiota composition. The results indicated that COS altered the composition of microbiota and inhibited the growth of dominant spoilage bacteria (Pseudomonas sp. and Aeromonas sp.). Compared with the control group, COS inhibited the increase in TVC and the production of TVB-N, delayed the degradation of inosine monophosphate (IMP) and hypoxanthine ribonucleotide (HxR), thus retarding the generation of hypoxanthine (Hx). COS improved the quality of silver carp fillets during chilled storage, mainly due to the inhibitory effect on the growth of the dominant spoilage bacteria.

The cryoprotective effects of adding different concentrations (0.5%, 1% and 2% (m/m)) of fish scale gelatin on frozen-thawed surimi were investigated in terms of the molecular structure myofibrillar proteins and gel properties. After eight cycles of freezing and thawing, the solubility, sulfhydryl content and Ca²⁺-ATPase activity of myofibrillar proteins with 1% fish scale gelatin decreased by 49.2%, 17.4% and 31.2%, less than those in the control group without fish scale gelatin (69.8%, 26.6%, and 49.4%), respectively. The increase in surface hydrophobicity and carbonyl content was inhibited more by 1% fish scale gelatin (42.7% and 229.9%) than by commercial anti-freezer (159.4%). Meanwhile, adding fish scale gelatin obviously inhibited the deterioration of the rheological properties and gel properties of surimi during freeze-thaw cycles. Furthermore, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and differential scanning calorimetry (DSC) indicated that fish scale gelatin could inhibit myofibrillar protein degradation by interacting hydrophobically with the side chain of myofibrillar proteins as well as inhibiting ice crystal growth.

Foam is a disperse system in which a gas is dispersed in a liquid or semi-solid medium. It plays an important role in shaping the taste, texture and appearance of interface-dominated foods such as cream, ice cream, and beer. Researchers usually expect to clarify the formation and stabilization mechanism of foam in the food system when they explore an innovative combination of foaming technology and various interface-dominated foods. However, foam, a highly thermodynamically unstable system, is prone to drainage, polymerization, and disproportionation. There are various factors to consider when acquiring the best foam stability in a complicated food system. Therefore, this paper starts with a discussion of the mechanisms for foam instability, followed by a systematical review of the foaming characteristics of different substances and the mechanisms for the stability of foam in different foods. This paper focuses on explaining the effect of surfactants or processing aids, solid particles, and processing conditions or technologies on foam stability from the perspective of the gas-liquid interface, aiming to provide a theoretical guidance for the development and stabilization of foam in interface-dominated foods.

Dry-cured meat products are loved by consumers because of their unique flavor, but the high salt content in dry-cured meat products restricts their further development. As people have started to pay attention to a moderately low-sodium diet, how to achieve the goal of reducing salt content in meat products while ensuring product quality and safety has become a hot issue in this field. This article begins with an analysis of the relationship between the sodium salt content and quality of dry-cured meat products. Next, it focuses on the current processing technologies and strategies for low-salt dry-cured meat products, namely sodium salt substitution, new curing technologies based on vacuum, ultra-high pressure, ultrasonic or pulse electric field, and saltiness perception enhancement technologies. Moreover, the principles of the different salt reduction technologies, the mechanism of salty taste perception, and the impact of salt reduction on the quality of dry-cured meat products are analyzed, and the limitations of the existing studies and technologies are put forward. We hope that this review will provide some theoretical references for the development of low-salt dry-cured meat products.

Malondialdehyde (MDA) content is a primary indicator evaluating lipid oxidation level in oil-containing foods. However, total MDA compounds (tMDA) exist in both free MDA (fMDA) and bound MDA (bMDA) forms at the stage of lipid peroxidation. The traditional spectrophotometric assay quantifies the MDA after an acid hydrolysis process, only releasing limited levels of fMDA from bMDA, which named as rMDA. Considering lack of study about the effect of hydrolysis treatments on the efficiency and result accuracy in terms of MDA detection for fish products. In this study, an alkaline hydrolysis method was compared with the conventional trichloroacetic acid (TCA) hydrolysis. The results showed that the highest MDA content was obtained under hydrolysis of surimi samples with 1 mol/L NaOH for 60 min at 60 °C, which was about 2 times of that obtained from 15 g/100 mL TCA for 30 min. The alkaline hydrolysis was proved to produce more rMDA, exhibiting higher hydrolysis efficiency over the conventional method. Present works also optimized a protocol on derivatization and liquid-liquid extraction process prior to gas chromatography-mass spectrometry quantification. The hydrolysate was firstly regulated by HCl, allowing protein to fully precipitated by the following addition of TCA. This developed liquid-liquid extraction could reduce interference from presence of protein in the aqueous phase, achieving a more sensitive result with improved precision and recovery.