The production of galacturonic acid enriched fractions and their functionality

Widely targeted metabolomics analysis reveals the effect of soybean hull polysaccharides on nonvolatile components of plant-based yogurt and its metabolic pattern

Soybean hull polysaccharides (SHPS) enhance the physicochemical properties of plant-based yogurt. However, their effects on the nutritional profile and biochemical mechanisms remain unclear. This study aimed to assess the impact of SHPS addition on the nonvolatile components of plant-based yogurt and its underlying mechanisms through widely targeted metabolomics analysis. The results demonstrated that the addition of SHPS (0.2 %-1.0 % w/v) enhanced the levels of free amino acids, sugars, and organic acids, with the addition of 0.6 % w/v being particularly effective in improving yogurt quality. Widely targeted metabolomics analysis revealed 278 differential metabolites between yogurt supplemented with 0.6 % SHPS (SPY) and the control sample. SHPS increased the content of various metabolites, including amino acids and derivatives, saccharides, organic acids, and flavonoids, among others. Key metabolic pathways affected by SHPS included pantothenate and CoA biosynthesis; valine, leucine, and isoleucine biosynthesis; and benzoate degradation. As the primary component of SHPS, galacturonic acid affected the metabolic products in yogurt by participating in the pentose and glucuronate interconversions and ascorbate and aldarate metabolism pathways. These findings elucidate the role of SHPS in modulating the nutritional composition of plant-based yogurt, offering valuable insights into its functional mechanisms in food processing.

Enhancing of pretreatment on high solids enzymatic hydrolysis of food waste: Sugar yield, trimming of substrate structure

The development of high solids enzymatic hydrolysis (HSEH) technology is a promising way to improve the efficiency of bioenergy production from solid waste. Pretreatment methods such as ultrasound (USP), freeze-thaw (FTP), hydrothermal (HTP), and dried (DRD) were carried out to evaluate the effect and mechanism of the pretreatment methods on the HSEH of FW. The reducing sugar of HTP and DRD reached 94.75% and 94.92% of the theoretical value. HTP and DRD could reduce the crystallinity of FW. DRD resulted in lower alignment and the occurrence of fractures of the substrate and exposed the α-1,4 glycosidic bond of starch. The high destructive power of HTP and DRD reduced the obstacles caused by the high solid content. Moreover, DRD consumed only 27.62% of the total energy of HTP. DRD could be a promising pretreatment methods for glucose recovery for its high product yield, significant substrate destruction, and economic feasibility.

TLR 2/1 interaction of pectin depends on its chemical structure and conformation

Citrus pectins have demonstrated health benefits through direct interaction with Toll-like receptor 2. Methyl-ester distribution patterns over the homogalacturonan were found to contribute to such immunomodulatory activity, therefore molecular interactions with TLR2 were studied. Molecular-docking analysis was performed using four GalA-heptamers, GalA₇Me⁰, GalA₇Me^1,6, GalA₇Me^1,7 and GalA₇Me^2,5. The molecular relations were measured in various possible conformations. Furthermore, commercial citrus pectins were characterized by enzymatic fingerprinting using polygalacturonase and pectin-lyase to determine their methyl-ester distribution patterns. The response of 12 structurally different pectic polymers on TLR2 binding and the molecular docking with four pectic oligomers clearly demonstrated interactions with human-TLR2 in a structure-dependent way, where blocks of (non)methyl-esterified GalA were shown to inhibit TLR2/1 dimerization. Our results may be used to understand the immunomodulatory effects of certain pectins via TLR2. Knowledge of how pectins with certain methyl-ester distribution patterns bind to TLRs may lead to tailored pectins to prevent inflammation.

Intestinal anti-inflammatory effects of artichoke pectin and modified pectin fractions in the dextran sulfate sodium model of mice colitis. Artificial neural network modelling of inflammatory markers

Anti-inflammatory properties of artichoke pectin and modified fractions (arabinose- and galactose-free) used at two doses (40 and 80 mg kg-1) in mice with colitis induced by dextran sulfate sodium have been investigated. Expression of pro-inflammatory markers TNF-α and ICAM-I decreased in groups of mice treated with original and arabinose-free artichoke pectin while IL-1β and IL-6 liberation was reduced only in mice groups treated with original artichoke pectin. A decrease in iNOS and TLR-4 expression was observed for most treatments. Intestinal barrier gene expression was also determined. MUC-1 and Occludin increased in groups treated with original artichoke pectin while MUC-3 expression also increased in arabinose-free pectin treatment. Galactose elimination led to a loss of pectin bioactivity. Characteristic expression profiles were established for each treatment through artificial neural networks showing high accuracy rates (≥90%). These results highlight the potential amelioration of inflammatory bowel disease on mice model colitis through artichoke pectin administration.

Investigation of cell wall polysaccharides from flour made with waste peel from unripe banana (Musa sapientum) biomass

BACKGROUND

The peel from unripe banana biomass is an agroindustrial waste. The present study aimed: (i) to extract pectin from enzymatically-treated waste peel from unripe banana biomass (WPUBB) using a Box-Behnken design to optimize the extraction conditions (temperature, pH and extraction time) and obtain a maximum yield and (ii) to fractionate the polysaccharides from WPUBB employing sequential extractions using different solvents.

RESULTS

The optimized product was obtained at 86 °C, pH 2.00, for 6 h and it presented a yield of 11.63%. The optimized product had low galacturonic acid content and a high amount of glucose (82.3%), suggesting the presence of starch (as confirmed by the bi-dimensional heteronuclear single quantum coherence NMR spectrum). All of the fractionated polysaccharides had a high glucose content. Low amounts of pectin were found in the water, chelating and diluted alkali-soluble fractions. The fractions extracted using NaOH indicated the presence of glucuronoarabinoxylans.

CONCLUSION

Glucose was the main monosaccharide found in all the fractions extracted from the WPUBB. Although the present study suggests that WPUBB is still not suitable for pectin extraction using current technologies, other compounds, such as resistant starch and glucuronoarabinoxylans, were found, suggesting that WPUBB could be used in the development of food formulations. © 2019 Society of Chemical Industry.

Spotlight on fungal pectin utilization-from phytopathogenicity to molecular recognition and industrial applications

Pectin is a complex polysaccharide with D-galacturonic acid as its main component that predominantly accumulates in the middle lamella of the plant cell wall. Integrity and depolymerization of pectic structures have long been identified as relevant factors in fungal phytosymbiosis and phytopathogenicity in the context of tissue penetration and carbon source supply. While the pectic content of a plant cell wall can vary significantly, pectin was reported to account for up to 20-25% of the total dry weight in soft and non-woody tissues with non- or mildly lignified secondary cell walls, such as found in citrus peel, sugar beet pulp, and apple pomace. Due to their potential applications in various industrial sectors, pectic sugars from these and similar agricultural waste streams have been recognized as valuable targets for a diverse set of biotechnological fermentations.Recent advances in uncovering the molecular regulation mechanisms for pectinase expression in saprophytic fungi have led to a better understanding of fungal pectin sensing and utilization that could help to improve industrial, pectin-based fermentations. Related research in phytopathogenic fungi has furthermore added to our knowledge regarding the relevance of pectinases in plant cell wall penetration during onset of disease and is therefore highly relevant for agricultural sciences and the agricultural industry. This review therefore aims at summarizing (i) the role of pectinases in phytopathogenicity, (ii) the global regulation patterns for pectinase expression in saprophytic filamentous fungi as a highly specialized class of pectin degraders, and (iii) the current industrial applications in pectic sugar fermentations and transformations.

Modeling the bioconversion of polysaccharides in a continuous reactor: A case study of the production of oligogalacturonates by Dickeya dadantii

In the quest for a sustainable economy of the Earth's resources and for renewable sources of energy, a promising avenue is to exploit the vast quantity of polysaccharide molecules contained in green wastes. To that end, the decomposition of pectin appears to be an interesting target because this polymeric carbohydrate is abundant in many fruit pulps and soft vegetables. To quantitatively study this degradation process, here we designed a bioreactor that is continuously fed with de-esterified pectin (PGA). Thanks to the pectate lyases produced by bacteria cultivated in the vessel, the PGA is depolymerized into oligogalacturonates (UGA), which are continuously extracted from the tank. A mathematical model of our system predicted that the conversion efficiency of PGA into UGA increases in a range of coefficients of dilution until reaching an upper limit where the fraction of UGA that is extracted from the bioreactor is maximized. Results from experiments with a continuous reactor hosting a strain of the plant pathogenic bacterium Dickeya dadantii and in which the dilution coefficients were varied quantitatively validated the predictions of our model. A further theoretical analysis of the system enabled an a priori comparison of the efficiency of eight other pectate lyase-producing microorganisms with that of D. dadantii Our findings suggest that D. dadantii is the most efficient microorganism and therefore the best candidate for a practical implementation of our scheme for the bioproduction of UGA from PGA.