This study aimed to evaluate the efficiency of edible films made from chlorogenic acid/chitosan (CGA/CS) nanoparticles combined with photodynamic technology (PDT). Hydroxypropyl starch (HS) and κ-carrageenan (KC) were used as the main ingredients in the preservation of Mongolian cheese under the PDT condition. The mechanical characteristics, water vapor adsorption, solubility, permeability, and release of chlorogenic acid in aqueous media were evaluated. The incorporation of CGA/CS significantly enhanced the tensile strength and barrier characteristics of the edible films. The antimicrobial efficacy of the edible film was assessed over a period of 7 days while the cheese was being stored, followed by PDT application. The use of antimicrobial PDT did not cause lipid oxidation in cheese samples. Additionally, the combination of CGA/CS@HS/KC helped to reduce fat oxidation in Mongolian cheese. Utilizing an edible film in conjunction with PDT presents a viable solution for prolonging the shelf life of Mongolian cheese while maintaining its sensory attributes and nutritional qualities.

This study aimed to elaborate the combination effect of polysaccharides on physicochemical properties and in vitro digestive behavior of astaxanthin (AST)-loaded Pickering emulsion gel. AST-loaded Pickering emulsion gel was prepared by heating Pickering emulsion with konjac glucomannan (KGM) and κ-carrageenan (CRG). The microstructure revealed that adding the two polysaccharides resulted in Pickering emulsion forming a network structure. It exhibited a denser and more uniform network structure, enhancing its mechanical properties four times and increasing its water-holding capacity by 20 %. In vitro digestion experiments demonstrated that the release of free fatty acids from the Pickering emulsion gel (4.25 %) was notably lower than that from conventional Pickering emulsion (17.19 %), whereas AST bioaccessibility was remarkably low at 0.003 %. It provided a feasible strategy to regulate the bioaccessibility in Pickering emulsion, which has theoretical significance to guide the current eutrophic diet people.

The synergistic interaction gels (SIGs) can be created by blending konjac glucomannan (KGM) and κ-carrageenan, and have been applied to modify and improve the rheological and texture properties of food system. However, the assembly behaviors between them are still unclear. This work revealed that the presence of KGM promoted phase transition of nearby κ-carrageenan molecules probably by contributing to entropy increment. Subsequently, the rest of κ-carrageenan transformed into helical structure, assembled into a series of laterally arranged trigonal units and formed a three-dimensional network. In KGM/κ-carrageenan SIGs, the size of high density domains (Ξ) in aggregates and the distance of these high density domains (ξ) were narrowed firstly and then enlarged as increasing of KGM content. These nano-scale structure features were responsible for the relative higher gel strength for KGM/κ-carrageenan SIGs with proportion ratios of 1:9 (K1C9) and 3:7 (K3C7). This study serves to facilitate the design and production of SIGs with the requisite performance characteristics.

κ-Carrageenan is a soluble dietary fiber widely used in meat products. Although its regulatory effect on glycolipid metabolism has been reported, the underlying mechanism remains unclear. The present study established a pork diet model for in vitro digestion to study how κ-carrageenan affected its digestive behavior and lipid bioavailability. The results revealed that κ-carrageenan addition to a pork-based high-fat diet reduced the rate of lipolysis and increased the number and size of lipid droplets in an in vitro digestion condition. However, κ-carrageenan did not inhibit lipolysis when lipids and κ-carrageenan were mixed directly or with the addition of pork protein. Furthermore, the pork protein in the diet significantly enhanced the inhibitory effect of κ-carrageenan on lipolysis with decreased proteolysis and raised hydrophobicity of protein hydrolysate. Our findings suggest that κ-carrageenan can inhibit dietary lipid bioavailability by interacting with pork protein in meat products or meat-based diets during digestion and indicate the positive role of carrageenan in the food industry to alleviate the excessive accumulation of lipids in the body.

Benzyl isothiocyanate (BITC) is a naturally active bacteriostatic substance and κ-carrageenan (KC) is a good film-forming substrate. In the present study, a nanoemulsion incorporating BITC was fabricated with a particle size of 224.1 nm and an encapsulation efficiency of 69.2 %. Subsequently, the acquired BITC nanoemulsion (BITC-NE) was incorporated into the KC-based film, and the light transmittance of the prepared composite films was lower than that of the pure KC film. Fourier transform infrared spectroscopy and scanning electron microscopy revealed that BITC-NE was compatible with the KC matrix. BITC-NE incorporation enhanced the tensile strength of the KC-based films by 33.7 %, decreased the elongation at break by 33.8 %, decreased the water vapor permeability by 60.1 %, increased the maximum thermal degradation temperature by 48.8 %, and decreased the oxygen permeability by 42 % (p < 0.05). Furthermore, the composite films showed enhanced antimicrobial activity against Staphylococcus aureus, Salmonella typhimurium, and Pseudomonas fluorescens. The developed KC-based composite films were applied to wrap raw beef, which significantly delayed the increase in total viable count, total volatile base nitrogen content, and thiobarbituric acid reactive substances, and prolonged the shelf-life of the raw beef by up to 10 days. These results indicated that the composite films prepared by incorporating BITC nanoemulsions into KC matrices have great antimicrobial application potential.

κ-Carrageenan (CG) was employed to mask the bitterness induced by 50% KCl in surimi gels to achieve salt reduction and gel performance improvement. The combination of KCl and CG (KCl + CG) yielded the increased textural characteristics and water-holding capacity (WHC) of surimi gels and facilitated the transition of free water to immobilized water. In addition, the KCl + CG supplement increased the turbidity and particle size of myofibrillar protein (MP) sols but decreased the surface hydrophobicity in a dose-dependent manner. The hydrophobic interactions and disulfide bonds played crucial roles in maintaining the stability of MP gels. The specific binding of potassium ions to the sulfate groups of CG limited the release and diffusion of potassium ions from the surimi gels during oral processing, effectively masking the bitterness perception and maintaining the saltiness perception. This study provides a promising strategy to reduce the utilization of sodium salt in surimi products.

The demand for crayfish surimi products has grown recently due to its high protein content. This study examined the effects of varying κ-carrageenan (CAR) and crayfish surimi (CSM) concentrations on the gelling properties of CAR-CSM composite gel and its intrinsic formation process. Our findings demonstrated that with the increasing concentration of carrageenan, the quality of CAR-CSM exhibited rising trend followed by subsequently fall. Based on the textural qualities, the highest quality CAR-CSM was achieved at 0.3% carrageenan addition. With the exception of chewiness, and the cooking loss of the gel system was 1.62%, whiteness was 82.35%, and the percentage of β-sheets increased to 57.18%. Further increase in CAR (0.4-0.5%) addition resulted in internal build-up of LCAR-CSM, conversion of intermolecular forces into disulfide bonds and gel breakage. This study exudes timely recommendations for extending the CAR application for the continuous development of crayfish surimi and its derivatives and its overall economic worth.

This study investigated the effect of ultrasound (US) combined with pre- and post-addition of κ-carrageenan (KC) on the gelling properties, structural characteristics and rheological behavior of myofibrillar proteins (MP) under low-salt conditions. The results showed that US combined with either pre- or post-addition of KC rendered higher gel strength and water holding capacity (WHC) of MP gels than those treated with US alone and added with KC alone (P < 0.05). US combined with pre-addition of KC facilitated the binding between MP and KC, which enhanced the gel strength and WHC of the mixed MP gels and significantly improved the rheological behavior of MP. This was also confirmed by the highest surface hydrophobicity, disulfide bonds and β-sheet content of the MP gels with US combined with pre-addition of KC. Moreover, microstructural results reflected a denser structure for the pre-addition of KC in combination with US. However, US combined with post-addition of KC resulted in limited MP unfolding and relatively weak hydrophobic interactions in the composite gels, which were less effective in improving the gel properties of the MP gels. This study provides potential strategies for enhancing the gelling properties of low-salt meat products via application of US and KC.

κ-Carrageenan (κ-Car) is an important material for preparing food gels and hydrogels. However, κ-Car gel has issues with high hardness and low water-holding capacity. Modification strategy of micronization is proposed for the first time to explore its influence on texture properties and gelling process of κ-Car gel, and to investigate the feasibility of κ-Car as a food matrix with low strength. κ-Car undergoing 60 min of micronization, the d(0.9) decreased by 79.33 %, SBET and Vtotal increased by 89.23 % and 95.27 %. The swelling rate and degree of gelling process increased significantly, and the microstructure changed from loose large pores to dense small pores resembling a \"honeycomb\". Importantly, the hardness of gel-60, Milk-60 and PNS-60 decreased by 72.52 %, 49.25 % and 81.37 %. In addition, WHC of gel-60, Milk-60 and PNS-60 was improved. IDDSI tests showed that κ-Car gels, milk gels and PNS gels can be categorized as level 6 (soft and bite-sized), except for PNS-60, which belongs to level 5 (crumbly and moist). Furthermore, the texture and bitter masking effect of milk gels and PNS gels were improved. In conclusion, this study demonstrated that micronization can be a novel approach to improve the gel properties of κ-Car, laying the groundwork for developing dysphagia foods.

Emulsion micro-gels exhibit significant potential as functional ingredients for modifying food texture, replacing saturated fats, or serving as templates for the controlled release of bioactive compounds. Structural design principles are being applied more frequently to develop innovative emulsion micro-gels. In this paper, whey protein concentrate (WPC), κ-carrageenan and sodium alginate (SA) were utilized for preparing emulsion micro-gels. To reveal the regulation mechanism of the structural and physicochemical properties of emulsion micro-gels on lipid digestion, the influence of SA additions on the structural, physicochemical properties and in vitro digestion behavior of κ-carrageenan/WPC-based emulsion micro-gel were explored. The FTIR results suggest that the emulsion micro-gels are formed through non-covalent interactions. With the increase of SA addition (from 0.7 g/100 mL to 1.0 g/100 mL), the decreased mean droplet size, the increased hardness, elasticity indexes, and water holding capacity, the reduced the related peak times all indicated that the emulsion micro-gels exhibit enhanced rheological, stability, and mechanical properties. It can be concluded from the microstructure, particle size distribution of the emulsion micro-gels during simulated digestion and free fatty acid release that both κ-carrageenan/WPC-based emulsion micro-gel and κ-carrageenan/WPC/SA-based emulsion micro-gel can inhibit lipid digestion due to the ability to maintain structural stability and hindering the penetration of bile salts and lipase through the hydrogel networks. And the ability is regulated by the binding properties the gel matrix and oil droplets, which determine the structure and physicochemical properties of emulsion micro-gels. The research suggested that the structure of emulsion micro-gels can be modified to produce various lipid digestion profiles. It may be significant for certain practical application in the design of low-fat food and controlled release of bioactive agents.