Physico-Chemical Properties of Sugar Beet Pectin-Sodium Caseinate Conjugates via Different Interaction Mechanisms

Casein-based conjugates and graft copolymers. Synthesis, properties, and applications

Biobased natural polymers, including polymers of natural origin such as casein, are growing rapidly in the light of the environmental pollution caused by many mass-produced commercial synthetic polymers. Although casein has interesting intrinsic properties, especially for the food industry, numerous chemical reactions have been carried out to broaden the range of its properties, most of them preserving casein's nontoxicity and biodegradability. New conjugates and graft copolymers have been developed especially by Maillard reaction of the amine functions of the casein backbone with the aldehyde functions of sugars, polysaccharides, or other molecules. Carried out with dialdehydes, these reactions lead to the cross-linking of casein giving three-dimensional polymers. Acylation and polymerization of various monomers initiated by amine functions are also described. Other reactions, far less numerous, involve alcohol and carboxylic acid functions in casein. This review provides an overview of casein-based conjugates and graft copolymers, their properties, and potential applications.

Polymorphisms of CCSER1 Gene and Their Correlation with Milk Quality Traits in Gannan Yak (Bos grunniens)

Coiled-coil serine-rich protein 1 (CCSER 1) gene is a regulatory protein gene. This gene has been reported to be associated with various economic traits in large mammals in recent years. The aim of this study was to investigate the association between CCSER1 gene single nucleotide polymorphisms (SNPs) and Gannan yaks and to identify potential molecular marker loci for breeding milk quality in Gannan yaks. We genotyped 172 Gannan yaks using Illumina Yak cGPS 7K liquid microarrays and analyzed the correlation between the three SNPs loci of the CCSER1 gene and the milk qualities of Gannan yaks, including milk fat, protein and casein. It was found that mutations at the g.183,843A>G, g.222,717C>G and g.388,723G>T loci all affected the fat, protein, casein and lactose traits of Gannan yak milk to varying extents, and that the milk quality of individuals with mutant phenotypes was significantly improved. Among them, the milk fat content of AG heterozygous genotype population at g.183,843A>G locus was significantly higher than that of AA and GG genotype populations (p < 0.05); the casein and protein content of mutant GG and CG genotype populations at g.222,717C>G locus was significantly higher than that of wild-type CC genotype population (p < 0.05); and the g.388,723G>T locus of the casein and protein contents of the mutant TT genotype population were significantly higher (p < 0.05) than those of the wild-type GG genotype population. These results provide potential molecular marker sites for Gannan yak breeding.

Effects of Salts on Structural, Physicochemical and Rheological Properties of Low-Methoxyl Pectin/Sodium Caseinate Complex

The addition of salts is an effective way to improve the properties of polysaccharide/protein complexes for use in foods. However, there is no comparative study on the effects of different ions on the complex system of low methoxyl pectin (LMP)/ sodium caseinate (CAS) complex. The effects of different concentrations of three salt ions (Na⁺, K⁺, Ca²⁺) on the physicochemical and rheological properties of the LMP/CAS complex were determined in this study, and the structure of LMP/CAS complex was characterized. The results showed that the addition of these three salt ions affected zeta potential, particle size, and turbidity of the LMP/CAS complex, and lead the LMP/CAS complex to form a more regular and uniform network structure, which helped improve its stability, solubility, and rheological properties. The particle size and turbidity value of the complex achieved with Ca²⁺ were higher than those obtained using Na⁺ and K⁺. Moreover, the secondary structure of the proteins in the complex changed to adding high concentrations of Ca²⁺. Our study provides valuable information for the application of the LMP/CAS complex in the food industry.

Influence of sodium caseinate, maltodextrin, pectin and their Maillard conjugate on the stability, in vitro release, anti-oxidant property and cell viability of eugenol-olive oil nanoemulsions

The influence of protein (sodium caseinate-SC), polysaccharide (maltodextrin-MD; pectin-PC) and their Maillard conjugates (sodium caseinate maltodextrin conjugate-SCMDC; sodium caseinate pectin conjugate-SCPCC) were studied on the physico-chemical and biological properties of eugenol nanoemulsions/powder. The chemical composition was optimized using Taguchi design. The particles size of eugenol nanoemulsions with SC, MD, PC, SCMDC and SCPCC were 104.6, 323.5, 1872, 181.7, and 454.4 nm, respectively while their zeta potentials were -31.2, -28.5, -21.4, -40.1 and -25.1 mV, respectively. Turbidity studies revealed higher stability of nanoemulsion prepared with Maillard conjugate (SCMDC) compared to protein or polysaccharides alone. The dispersion of SCMDC eugenol nanoparticles in buffer was prepared to study its stability at different pH (3.0, 5.0, and 7.0) and temperature (4°, 37°, 60 °C) range. In-vitro enzymatic release study showed 31 and 74% release of eugenol after 6 h at pH 2.4 and 7.4, respectively. In vitro antioxidant capacity of SCMDC encapsulated eugenol was higher than native eugenol, as demonstrated by free radical scavenging assays. In comparison to native eugenol, E:SCMDC eugenol showed reduced toxicity. These findings suggested that nanoencapsulated eugenol (E:SCMDC) have a huge potential in nutraceutical and therapeutic applications.

Impact of Type of Sugar Beet Pectin-Sodium Caseinate Interaction on Emulsion Properties at pH 4.5 and pH 7

Equal parts of sugar beet pectin and sodium caseinate were interacted through electrostatic attraction, enzymatic crosslinking, and the Maillard reaction to prepare three oil-in-water emulsifier systems. Oil-in-water emulsions (10%) were processed via high shear overhead mixing at the natural pH of the emulsifier systems, followed by pH adjustment to pH 4.5 and pH 7. The emulsions were stable against coalescence, except for a slight increase in the mean droplet size for the enzymatic cross-liked emulsion at pH 4.5 over a 14-day storage period. This emulsion also showed the lowest absolute zeta (ζ)-potential value of near 30 mV. The Maillard interaction emulsifier system resulted in larger droplet sizes compared to the other two emulsifier systems. Small deformation oscillatory shear rheology assessment of the emulsion cream phases revealed an impact of the emulsifier system design at pH 4.5.

Valorization of spent black tea by recovery of antioxidant polyphenolic compounds: Subcritical solvent extraction and microencapsulation

Spent black tea (SBT), waste remaining after producing tea beverages, is potentially an underutilized source of antioxidant phenolic compounds. This study evaluated the integrated processes of subcritical solvent extraction of polyphenols from SBT followed by microencapsulation to improve the stability of obtained extract. Optimization of extraction conditions was carried out by response surface methodology for the best recovery of antioxidant phenolic compounds. Two variables [temperature (°C) and ethanol concentration (%)] were used to design the optimization model using central composite inscribed. Extraction temperature of 180°C and ethanol concentration of 71% were optimal for the highest yield of total polyphenols (126.89 mg gallic acid equiv./g SBT) and 2,2-diphenyl-1-picrylhydrazyl scavenging activity (69.08 mg gallic acid equiv./g SBT). The extract was encapsulated using pectin, sodium caseinate, and a blend of these compounds (ratio 1:1) as wall materials by spray drying. The wall material significantly influenced (p < .05) encapsulation efficiency, particle size, morphology, thermal stability, crystallinity, and storage stability. The blend of wall materials produced an amorphous powder with the highest phenolic retention (94.28%) in the accelerated storage at 45°C for 40 days. The microcapsules prepared with sodium caseinate were smaller with lowest mean diameter and highest thermal stability than the other types of materials. Obtained microencapsulates have potential use in different food systems to enhance their antioxidant property.