Gelation behaviors and mechanism of a new pectic polysaccharide from apple pomace as a potential gelatin substitute

Ficus awkeotsang Makino pectin in acidic environments: Insights into pectin structure, gelation behavior, and gel properties

This study demonstrated the gelation capacity, gelation behavior, and mechanism of Ficus awkeotsang Makino pectin (JFSP) in acidic media (pH 3.4-4.5). JFSP exhibited an extraordinary ability to spontaneously form a gel at a low polymer concentration (0.3 %, w/v) within the pH range of 3.75-4.05 at room temperature, without the need to introduce exogenous metal ions or co-solutes. Analysis of zeta potential and carboxyl dissociation extent revealed the protonation of free carboxyl groups within JFSP under acidic conditions. Atomic force microscopy and small angle X-ray scattering elucidated the aggregation morphology and folding conformation of JFSP. At pH 3.8, the correlation length (ξ) of JFSP chains decreased to around 1.67 nm. Rheological experiments confirmed the formation of a stronger gel network at pH 3.8 and 4.0, with good thermal and freeze-thaw stability. Isothermal Titration Calorimetry (ITC), temperature sweeps, and gelation force analyses emphasized the pivotal role of hydrogen bonds in JFSP gels at pH 3.8 and 4.0. Further reducing the pH to 3.4-3.6 disrupted the dynamic equilibrium of gel-driving forces, leading to the formation of a flocculated gel network. These findings deepen our understanding of JFSP behavior in low-acid conditions, which may be useful for further food formulations at these conditions.

Characterization and prebiotic potential of polysaccharides from Rosa roxburghii Tratt pomace by ultrasound-assisted extraction

In this study, polysaccharides (RRTPs) were extracted from Rosa roxburghii Tratt pomace by hot water or ultrasound (US)-assisted extraction. The structural properties and potential prebiotic functions of RRTPs were investigated. Structural characterization was conducted through HPAEC, HPGPC, GC-MS, FT-IR and SEM. Chemical composition analysis revealed that RRTPs extracted by hot water (RRTP-HW) or US with shorter (RRTP-US-S) or longer duration (RRTP-US-L) all consisted of galacturonic acid, galactose, glucose, arabinose, rhamnose and glucuronic acid in various molar ratio. US extraction caused notable reduction in molecular weight of RRTPs but no significant changes in primary structures. Fecal fermentation showed RRTPs could reshape microbial composition toward a healthier balance, leading to a higher production of beneficial metabolites including total short-chain fatty acids, curcumin, noopept, spermidine, 3-feruloylquinic acid and citrulline. More beneficial shifts in bacterial population were observed in RRTP-HW group, while RRTP-US-S had stronger ability to stimulate bacterial short-chain fatty acids production. Additionally, metabolic profiles with the intervention of RRTP-HW, RRTP-US-S or RRTP-US-L were significantly different from each other. The results suggested RRTPs had potential prebiotic effects which could be modified by power US via molecular weight degradation.

Exploring apple pectic polysaccharides: Extraction, characterization, and biological activities - A comprehensive review

Apple (Malus domestica) is a popular and ancient fruit of the Myrtaceae family. Apple fruit is well-known for its great nutritional and phytochemical content consisted of beneficial compounds such as polyphenols, polysaccharides, sterols, and organic acids. Polysaccharides extracted from different parts of the apple fruit, including the peel, pomace, or the whole fruit, have been extensively studied. Researchers have investigated the structural characteristics of these polysaccharides, such as molecular weight, type of monosaccharide unit, type of linkage and its position and arrangement. Besides this, functional properties and physicochemical and of apple polysaccharides have also been studied, along with the effects of extraction procedures, storage, and processing on cell wall polysaccharides. Various extraction techniques, including hot water extraction, enzymatic extraction, and solvent-assisted extraction, have been studied. From the findings, it was evident that apple polysaccharides are mainly composed of (1 → 3), (1 → 6): α-β-glycosidic linkage. Moreover, the apple polysaccharides were demonstrated to exhibit antioxidant, hepatoprotective, anti-cancer, hypoilipidemic, and enzyme inhibitory properties in vitro and in vivo. The potential applications of apple polysaccharides in the food, cosmetic, pharmaceutical, nutraceutical industries have also been explored in the present review. Overall, the research on apple polysaccharides highlights their significant potential as a source of biologically active compounds with various health benefits and practical applications.

Strong gelation capacity of a pectin-like polysaccharide in the presence of K+ ion

In the present study, a pectin-like apple polysaccharide (AP) obtained by metal precipitation technique was demonstrated to show strong gelling capacity in the presence of K+ ion upon cooling. Increasing amount of K+ addition monotonically promoted the gelation of AP, as characterized by the increased gelation temperature (Tgel), gel melting temperature (Tmelt) and the gel strength. Compared with K+ ion, Na+ was unable to induce AP gelation even at high ionic concentrations, but other monovalent cations (Rb+, Cs+) can induce the gelation as in the case of K+ addition. At room temperature, the minimum cationic concentration as required to induce AP gelation followed the order of K+ ≈ Cr+ (8 mM) > Rb+ (3.5 mM), indicating that cationic radius (Na+ < K+ < Rb+ < Cs+) played a dominant role in inducing AP gelation, but other factors may also be involved. Finally, the gelation behavior of AP in the presence of K+ was explained as the suppressed intermolecular electrostatic repulsion between AP chains due to the strong electrostatic shielding effect of K+, which led to the formation of a gel network mediated by intermolecular hydrogen bonding. This reported gelation property may allow AP to find application as a new gelling polysaccharide.

Apple pomace as an alternative substrate for butanol production

Butanol-producing strains Clostridium sp. UCM B-7570 and C. acetobutylicum UCM B-7407 were used for research from "Collection of strains of microorganisms and plant lines for food and agricultural biotechnology" of the Institute of Food Biotechnology and Genomics of the National Academy of Sciences of Ukraine, glycerol (BASF, Germany) and apple pomace (total moisture 4%) after apple juice production. The aim of this work was to study the possibility of using apple pomace by domestic butanol-producing strains of Clostridium sp. UCM B-7570 and C. acetobutylicum UCM B-7407 as a substrate. Producers were cultured on medium with different concentrations of apple pomace, glycerol was used for the inoculation. The presence of ethanol, acetone, and butanol in the culture liquid was determined using a gas chromatograph. It was determined that a significant part of the macrocomponent composition of the extracts can be used in bioconversion by producing strains of the genus Clostridium. It was determined that the highest concentration of butanol (10 g/dm3) was at a concentration of 120 g/dm3 in the extracts. The obtained data showed the possibility of using apple pomace as a substrate in biobutanol technology.