Effects of Non-Enzymatic Browning and Lipid Oxidation on Color of Ready-to-Eat Abalone during Accelerated Storage and Its Control

The new insight into the impact of hemocyanin on quality deterioration of Pacific white shrimp during refrigerated storage

This study explored the role of hemocyanin (Hc) in shrimp quality deterioration during storage. Pacific white shrimp (Litopenaeus vannamei) subjected to bloodletting and stored at 4 °C showed 22.97 % and 21.51 % reduction in peroxide value and thiobarbituric acid reactive substance (TBARS) at 3 d, respectively, compared to the control. Furthermore, key quality indicators, including K-value, water holding capacity, color, and total volatile basic nitrogen improved significantly. In washed shrimp model with exogenously added Hc and Cu2+, the effect of Hc group on promoting lipid oxidation was stronger than Cu2+ group, and TBARS level increased by 16.42 %. Cu2+ released from Hc activated adenosine monophosphate deaminase and accelerated inosine monophosphate degradation into hypoxanthine riboside and hypoxanthine, resulting in freshness loss. Hc also activated polyphenol oxidase, leading to shrimp blackening. This is the first study to reveal the impact of Hc and Cu2+ on the quality deterioration of Pacific white shrimp during storage.

Differences and mechanisms of color deterioration in three types of ready-to-eat shellfishes during storage

Ready-to-eat (RTE) abalones, scallops and oysters were prepared through a process of cooking, drying, vacuum packaging, and high-temperature sterilization, and were subjected to accelerated storage. Upon storage, the three RTE shellfishes all showed color deterioration, as indicated by darker color, decreased L* and W* values, and increased a* value. In contrast, the color deterioration of RTE oysters was more pronounced. Meanwhile, oxidation reactions occurred during storage, which were manifested as increased peroxide value, thiobarbituric acid reactive substances value and aldehyde content. Correlation analysis showed that the color indexes (L* and W*) of the three RTE shellfishes were negatively correlated with the contents of 5-hydroxymethylfurfural, hydrophilic pyrroles, hydrophobic pyrroles and quinones, suggesting that Maillard/Maillard-like reactions and phenolic oxidation reaction contributed to the color deterioration. The higher contents of reducing sugar, lipids and transition metal ions in RTE oysters make it more prone to non-enzymatic browning reactions, causing faster color deterioration.

Gel properties of sheep's hoof gelatin-dietary polysaccharide interpenetrating polymer network complex gels with application in low fat lamb patties

In order to explore new fat substitutes, we compared three dietary polysaccharides Pectin(PEC), Inulin (INU), and Konjac glucomannan (KGM) compounded with sheep hoof gelatin using different cross-linking methods [transglutaminase (Tg) enzyme; Tg enzyme & Ca2+] for the preparation of Semi-interpenetrating polymer network (Semi-IPN) and fully interpenetrating polymer network (IPN) gels. The optimal ratio was determined by comprehensively evaluating the addition of hydrogel to the lamb patties at different ratios. The results showed that PEC-IPN exhibited superior stability and textural properties compared to the Semi-IPN gels and control gels in each group. In addition, replacing 80 % of the fat in the lamb patties with PEC-IPN significantly improved the quality stability during storage, without affecting the sensory quality. Therefore, PEC-IPN instead of lamb patty fat offers a new approach for consumers.

Lipid-involved browning mechanism during the drying process of squid

The present study evaluated lipid-involved browning mechanism during the drying process of squid. Initially, different lipid-Maillard reaction (MR) models were conducted based on the composition of squid (lipids, reducing sugars and amino acids). The degree of MR as well as α-dicarbonyl compounds (α-DCs) and lipid oxidation-mediated browning products (pyrroles and lipofuscin-like pigments) were detected. The results indicated that arginine and ribose were blamed for the browning of dried squid. Moreover, lipid oxidation provided glyoxal and methylglyoxal to participate in MR, and long-time heating and salting produced more α-DCs and accelerated browning. Meanwhile, dried squid contained hydrophilic pyrrole (17.45 μg/g lipid) and hydrophobic pyrrole (113.00 μg/g lipid), and the content of lipofuscin-like pigments increased by 1.5-fold after drying. Finally, defatting treatment demonstrated that the browning of dried squid was moderately alleviated by fat removal (L* ↑, a* ↓ and b* ↓). These findings offer a novel perspective on moderately preventing the browning of dried aquatic products.

How lipids, as important endogenous nutrient components, affect the quality of aquatic products: An overview of lipid peroxidation and the interaction with proteins

As the global population continues to grow and the pressure on livestock and poultry supply increases, the oceans have become an increasingly important source of quality food for future generations. However, nutrient-rich aquatic product is susceptible to lipid oxidation during storage and transport, reducing its nutritional value and increasing safety risks. Therefore, identifying the specific effects of lipid oxidation on aquatic products has become particularly critical. At the same time, some lipid oxidation products have been found to interact with aquatic product proteins in various ways, posing a safety risk. This paper provides an in-depth exploration of the pathways, specific effects, and hazards of lipid oxidation in aquatic products, with a particular focus on the interaction of lipid oxidation products with proteins. Additionally, it discusses the impact of non-thermal treatment techniques on lipids in aquatic products and examines the application of natural antioxidants in aquatic products. Future research endeavors should delve into the interactions between lipids and proteins in these products and their specific effects to mitigate the impact of non-thermal treatment techniques on lipids, thereby enhancing the safety of aquatic products and ensuring food safety for future generations.

Effect of non-enzymatic browning on oysters during hot air drying process: Color and chemical changes and insights into mechanisms

Hot air drying (HAD) is an extensive method used on oysters and it causes the most intuitive change, a color change. However, the mechanism of color change remains unclear. This study showed that oysters underwent browning during the HAD process. The colorimetric parameter L* decreased while a* and b* increased, all of which were well described by the first-order color kinetic model. Mechanistically, the HDA process induced the oxidative browning of phenols and the generation of Maillard reaction products (5-hydroxymethylfurfural and hydrophilic pyrrole). Meanwhile, the HAD process caused lipid oxidation, leading to the reduction of phosphatidylethanolamine and the generation of reactive carbonyl compounds (aldehydes and α-dicarbonyl compounds). Moreover, the accumulation of hydrophobic pyrroles, a lipid-induced Maillard-like reaction product, was observed. These results suggest that, in addition to phenolic oxidation, sugar- and amino acid-mediated non-enzymatic browning reactions, lipid-mediated Maillard-like reactions play important roles in oyster darkening during the HAD process.

Quality properties of fish ball with abalone and its relationship with sensory properties

In this work, whiteness, water-holding capacity, gel strength, textural profile analysis were performed to examine the quality of fish balls with abalone (FBA). In addition, a correlation between quality and sensory properties was established. The addition of abalone significantly increased the water holding capacity, gel strength and textural properties of FBA, and decreased their whiteness, the best overall quality was achieved at 9 % w/w abalone addition. The E-nose and E-tongue results revealed that the addition of abalone changed the flavour of FBA. HS-SPME-GC-MS identified 65 volatile organic compounds (VOCs) and proved to be effective in reducing fishy flavour. E-nose can distinguish between the VOCs in FBA. Moreover, Umami and 1-octen-3-ol can serve as important indicators to observe changes in the quality of FBA, as they were positively connected with WHC, gumminess, chewiness, resilience, a*, hexanal, etc. The results provided a theoretical basis for the development of abalone and surimi products.

The Chemical Reactivity of Membrane Lipids

It is well-known that aqueous dispersions of phospholipids spontaneously assemble into bilayer structures. These structures have numerous applications across chemistry and materials science and form the fundamental structural unit of the biological membrane. The particular environment of the lipid bilayer, with a water-poor low dielectric core surrounded by a more polar and better hydrated interfacial region, gives the membrane particular biophysical and physicochemical properties and presents a unique environment for chemical reactions to occur. Many different types of molecule spanning a range of sizes, from dissolved gases through small organics to proteins, are able to interact with membranes and promote chemical changes to lipids that subsequently affect the physicochemical properties of the bilayer. This Review describes the chemical reactivity exhibited by lipids in their membrane form, with an emphasis on conditions where the lipids are well hydrated in the form of bilayers. Key topics include the following: lytic reactions of glyceryl esters, including hydrolysis, aminolysis, and transesterification; oxidation reactions of alkenes in unsaturated fatty acids and sterols, including autoxidation and oxidation by singlet oxygen; reactivity of headgroups, particularly with reactive carbonyl species; and E/Z isomerization of alkenes. The consequences of reactivity for biological activity and biophysical properties are also discussed.