In this study, an emulsion gel was constructed using hydroxypropyl methylcellulose-flaxseed gum (HPMC-FG) as the emulsifier, and the effects of oil phase gelation induced by different bio-waxes, candelilla wax (CW), beewax (BW), and CW-BW mixture on the microstructure, rheological properties, and stability of the emulsion gel were systematically investigated. The results showed that the combination of CW with BW had a significant synergistic effect on the formation of oleogels, primarily through van der Waals forces, forming a three-dimensional network structure of needle-like crystals embedded in snowflake-like aggregates in the oil phase. Compared with the HPMC-FG emulsion gel without oil-phase gelation, the emulsion gel modified by the CW-BW composite gelator presented smaller droplet size and higher deformation resistance. After long-term storage at room temperature and freeze-thawing treatment, no obvious oil droplet coalescence or oil syneresis was observed in this system, demonstrating excellent storage stability and freeze-thawing stability. This study can provide a theoretical basis and technical support for the development of novel animal fat substitutes.

In this study, under identical gelatinization conditions, different pretreatment methods (hydrothermal, microwave, and autoclaving) combined with an ultrasound-assisted enzymatic approach were used to prepare sweet potato resistant starch type Ⅲ (RS3), and their structural and physicochemical properties were compared and analyzed. The results indicated that native sweet potato starch primarily exhibited spherical granules, showing Maltese crosses under polarized light microscopy. However, the Maltese cross disappeared after all three gelatinization pretreatments. The surface of RS3 prepared using hydrothermal and autoclaving pretreatments exhibited porous structures, whereas the surface of RS3 prepared by microwave showed partial depressions with a scaly structure. Compared with native sweet potato starch, the particle size of sweet potato RS3 increased, and the crystal structure changed from type A to type B. Additionally, the gelatinization enthalpy (ΔH) increased from 6.28 to 13.14–24.69 J/g, the amylose content from 15.54% to 19.19%–23.54%, and the resistant starch content from 21.69% to 46.25%–54.72%. Among the three pretreatment methods, sweet potato RS3 pretreated by microwave showed the highest degree of short-range order and crystallinity; the greatest amylose content, gelatinization enthalpy, and resistant starch content; and the lowest solubility, swelling power, and starch hydrolysis rate. In conclusion, under identical gelatinization conditions, microwave pretreatment more effectively promoted the formation of compact granular structures in sweet potato RS3 compared with hydrothermal and autoclaving pretreatments. Moreover, microwave pretreatment enhanced the double helix content and thermal stability of starch, reduced the solubility and swelling capacity, and increased the amylose content to a greater extent. Consequently, sweet potato RS3 obtained via microwave pretreatment exhibited the highest resistant starch content and lowest starch hydrolysis rate, indicating superior digestive resistance.

In this study, the lipid-lowering effects of κ-carrageenans with different molecular masses (5.2, 15.5 and 36.2 kDa), prepared using a photocatalytic degradation method, were compared in a mouse model of obesity induced by a high-fat diet. Body mass, epididymal fat mass, oral glucose tolerance, four serum lipid parameters (triglycerides (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C)), inflammatory factors (interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α)), hepatic lipid content, and pathomorphological changes in the liver, colon, and adipose tissue of mice were measured. The results indicated that all degraded κ-carrageenans exhibited lipid-lowering activity in a molecular mass-dependent manner. Among these, the 15.5 kDa κ-carrageenan demonstrated the most pronounced lipid-lowering effect. It significantly inhibited body mass gain and epididymal fat accumulation in high-fat diet-fed mice (P < 0.05) and alleviated impaired glucose tolerance, effectively regulating blood lipid levels, reducing serum TC, TG and LDL-C by 12.40%, 8.74%, and 5.02% respectively, whilst significantly increasing HDL-C levels by 11.34%. Additionally, it significantly reduced serum levels of the inflammatory cytokine IL-6 and effectively alleviated hepatic steatosis. This study revealed that the lipid-lowering activity of κ-carrageenan is closely related to its molecular mass, but does not simply increase as its molecular mass decreases. This study provides new experimental evidence for an in-depth understanding of the biological activity of κ-carrageenan, and offers new data support and theoretical references for the development of κ-carrageenan-based functional foods with specific molecular mass characteristics.

This study aimed to explore the recombinant expression of κ-carrageenase Cgk483 from Photobacterium rosenbergii and its application in preparing carrageenan oligosaccharides, which were structurally characterized and evaluated for in vitro hypolipidemic effects. Through gene cloning and heterologous expression, the electrophoretically pure recombinant enzyme Cgk483 was successfully obtained, with a molecular mass of 35.89 kDa and its specific activity was 489.88 U/mg, which was approximately 10 times higher than that of the wild-type enzyme. Enzyme kinetics studies showed that the optimal reaction temperature and pH for Cgk483 were 40 ℃ and 8.0, respectively. It was stable at temperatures below 40 ℃ and within the pH range of 5.0-10.0. Fe²⁺, Na⁺, and Ba²⁺ were found to enhance the enzyme activity. Using the recombinant enzyme Cgk483, κ-carrageenan oligosaccharides consisting of disaccharide, tetrasaccharide and hexasaccharide were successfully prepared. Structural analysis indicated that the enzymatic hydrolysis did not disrupt the main chain but resulted in the exposure of hydroxyl and other groups, improving the solubility of κ-carrageenan oligosaccharides. In vitro hypolipidemic assay demonstrated that κ-carrageenan oligosaccharides significantly inhibited oxidized low-density lipoprotein (Ox-LDL)-induced foam cell formation in RAW264.7 macrophages, reducing lipid accumulation. This study provides a new idea for the efficient preparation of κ-carrageenan oligosaccharides for use in the prevention and treatment of atherosclerosis.

In this study, chondroitin sulfates were prepared from tilapia processing by-products (head, backbone, fin and tail) by two-step enzymatic hydrolysis followed by precipitation with cetane pyridine chloride. Their physicochemical properties and structural characteristics were analyzed by ultraviolet (UV) spectroscopy, cellulose acetate electrophoresis, infrared spectroscopy and high performance liquid chromatography (HPLC). The results showed that fish heads and tails mainly contained type C chondroitin sulfate (Δdi6S) at levels of 46.10% and 41.01%, respectively; fish backbones and fins mainly contained type A chondroitin sulfate (Δdi4S) at levels of 71.86% and 69.59%, respectively. The decreasing order of the purity of chondroitin sulfates from these body parts was heads (90.37%), tails (83.33%), backbones (59.76%), and fins (52.01%). Monosaccharide composition analysis showed that chondroitin sulfates from fish heads, backbones, fins and tails were mainly composed of glucuronic acid, glucose and galactosamine in different proportions, and their number-average molecular masses were 51422, 18402, 19481 and 76371, respectively. The types and composition of chondroitin sulfate extracted from different body parts were significantly different. Chondroitin sulfates extracted from tilapia heads and tails were similar to that from shark cartilage, and thus may have the potential to replace chondroitin sulfate from shark cartilage.

Arsenic is a poisonous semi-metal (metalloid) and has been identified as a human carcinogen. Arsenic poisoning can cause a variety of health damage to the human body. Arsenic can exist in both inorganic and organic forms. It is generally considered that inorganic arsenic is more toxic than organic arsenic. Arsenolipids are organic arsenic and widely exist in tissues of marine organisms. Arseniolipids have been previously thought to be extremely low toxic. With the progress and development of science and technology in recent years, intensive research has been conducted on arsenolipids, and the speciation analysis and toxicity evaluation of arsenolipids have gradually become a hot spot. At present, there are three known species of arsenolipids, namely arsenic-containing fatty acids (AsFAs), arsenic-containing hydrocarbons (AsHCs) and arsenic-containing phospholipids (AsPLs), which differ in their toxicity. However, due to the complex speciation pattern, low bioavailability and low content of arsenolipids, and the difficulty to extract and detect them, the mechanism of arsenolipid toxicity remain unclear. Therefore, this paper reviews the latest progress in the methods for speciation analysis and toxicity evaluation of arsenolipids in marine organisms, with the aim to provide an inspiration for further elucidating the speciation, toxicity, and human health risk of arsenolipids.

Soluble dietary fiber (SDF) was extracted from Sargassum hemiphyllum fermented with Aspergillus niger or Aspergillus oryzae in order to investigate the effect of fungal fermentation on the yield, structural improvement, functional properties and antioxidant activity of SDF from S. hemiphyllum. The results showed that SDF prepared by fermentation with the two strains had advantages over each other. Compared with the untreated control group, A. oryzae fermentation increased the yield of SDF by 3.625 times, and the obtained SDF, which was bright in color and loose in structure, had higher purity and lower molecular mass (6.3 kDa), and consequently higher water-holding capacity (WHC) and sodium cholate adsorption capacity. A. niger fermentation increased the yield of SDF by 3.375 times, and the molecular mass of the obtained SDF was 39.4 kDa, which had a porous structure and significantly improved water-holding capacity, cholesterol and sodium cholate adsorption capacity. In vitro antioxidant experiments showed that fermentation improved the hydroxyl radical scavenging capacity of SDF, and decreased its scavenging capacity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation radical and oxygen radical. In summary, this study can provide a reference for the preparation of SDF by fungal fermentation and its development and application in functional foods.

In this study, we explored the effect of two arsenolipids with different molecular masses, AsHC 332 and AsHC 346, which are commonly found in seafood, on aging and lifespan-related indicators in the model organism Caenorhabditis elegans. The possible mechanism by which the arsenolipids promote aging was analyzed by measuring the expression of DAF-16 protein in the nematode, the longevity of aging mutants and stress-related genes. The results showed that AsHCs significantly reduced the body length, body width, brood size and head thrash frequency of C. elegans in a dose-dependent manner (P < 0.05). Moreover, the resistance to heat stress (P < 0.0001) and ultraviolet stress (P < 0.05) was significantly reduced by AsHCs. The lifespan of C. elegans was significantly shortened (P < 0.01). The accumulation of lipofuscin was increased (P < 0.001). The relative expression of the daf-16, sod-3, ctl-1, gst-4 and hsp-16.2 genes was up-regulated, while the nuclear localization of DAF-16 was not significantly promoted, and there was no effect on the lifespan of the daf-16(mu86) mutant. AsHC 332 and AsHC 346 had the same toxic effects on nematode aging, which may shorten the lifespan of C. elegans by regulating the transcription factor DAF-16.