Characterisation of cell-wall polysaccharides from mandarin segment membranes

Effect of pulp cell wall polysaccharides on citrus fruit with different mastication traits

Mastication trait is a primary quality attribute of citrus fruit, influencing consumer demands and industrial processing conditions. However, the underlying causes of differences in mastication traits of citrus remain unclear. In this study, microscopy, spectroscopy and diffraction techniques were applied to investigate the physicochemical properties of Hongmeiren (HMR), Satsuma (WM) and Nanfeng tangerine (NF) with superior, moderate and inferior mastication traits, respectively. Ultrastructure indicated that NF had more neatly arranged and regularly shaped cells than HMR and WM. The monosaccharide composition of NF revealed that multi-branched Na2CO3-soluble pectin (NSF) enhanced intercellular adhesion. Additionally, FT-IR analysis revealed more intense vibrations of O2-H····O6 intramolecular hydrogen bonds within NF cellulose, which resulted in a higher crystallinity of cellulose (73.75%) than HMR (32.53%) and WM (43.76%). Overall, the high content and crystallinity of cellulose, the multi-branched NSF and the high content of hemicellulose contributed to the inferior mastication trait of citrus fruit.

Structural Characterization of Polysaccharides in Waste Liquor Produced by Wet Decortication of Sesame Seeds

The wet decortication of sesame seeds produces wastewater containing diverse minerals and organic pollutants that could be valuable resources for the food industry. This investigation aimed to reclaim, purify, and characterize the polysaccharides contained in the waste liquor from the sesame decortication industry. The purified polysaccharide fractions were characterized using monosaccharide analysis, GPC (high-performance gel permeation chromatography), FT-IR (Fourier-transform infrared) spectroscopy, methylation analysis, 1D and 2D Nucleai Magnetic Resonance (NMR) analysis, and thermal analysis. Four fractions were found (SSP-1,-2,-3, -4), of which SSP-2 was proportionately the largest and most interesting. The backbone of SSP-2 is mainly composed of (1→2,4)-β-_D-Xylp residues with side chains connected to the O-4 position, with many T-β-_D-Galp and (1→5)-α-_L-Araf residues, and fewer (1→4)-α-_D-Glcp, (1→2)-α-_L-Rhap, T-α-_L-Araf, and (1→2)-β-_D-GlcpA residues. An efficient method for removing the polysaccharides would simplify wastewater treatment while finding a use for them would benefit the sesame, food, and pharmaceutical industries.

Short-time acoustic and hydrodynamic cavitation improves dispersibility and functionality of pectin-rich biopolymers from citrus waste

Pectin is a valuable biopolymer used as a natural, clean label additive for thickening and gelling. However, industry faces issues with dispersibility and stability of pectin formulations. To address these issues, the effect of short processing time (30-180 s) with hydrodynamic (HC) and acoustic cavitation (AC) on the dispersibility and gelling functionality of mandarin pectin-rich polysaccharide (M-PRP) was investigated. Short-time processing with HC and AC did not affect polymer composition. HC, but not AC, decreased polydispersity index (PDI) from 0.78 to 0.68 compared to the control. Electron and atomic force microscopy showed that HC and AC decreased aggregation of fibrous and matrix polymers. Both treatments increased apparent viscosity significantly from 0.059 Pa s to 0.30 Pa s at 10 ^-s. The pectin dispersions showed good gelling capacity upon addition of calcium (final conc. 35 mM). HC and AC treatments for 150 s led to gels that were 7 and 4 times stronger (as measured by peak force) than the control with more homogeneous, less porous structures. In conclusion, short-time HC and AC can improve the dispersibility and functionality of citrus pectin without affecting composition, and are promising technologies to facilitate the use of pectin in industry applications.

Safety Evaluation and Whole Genome Sequencing of Aspergillus japonicas PJ01 Reveal Its Potential to Degrade Citrus Segments in Juice Processing

Aspergillus japonicas PJ01 (A. japonicas PJ01) is a strain isolated from the rotten branches. In previ-ous studies, it was shown that it can produce complex enzymes to degrade polysaccharide com-ponents. In this study, we evaluated the safety of its crude enzyme solution. Acute oral toxicity, subchronic toxicity, micronucleus and sperm malformation tests all validated the high biologi-cal safety for the crude enzymes. Secondly, we carried out the citrus segment degradation ex-periment of crude enzyme solution. Compared with the control group, the crude enzyme solu-tion of A. japonicas PJ01 can completely degrade the segments in 50 min, which provides the basis for enzymatic peeling during juice processing. The whole genome sequencing showed that the genome of A. japonicus PJ01 has a GC content of 51.37% with a size of 36204647 bp, and encoded 10070 genes. GO, COG, KEGG and CAZy databases were used in gene annotation analyses. Pathway enrichment showed many genes related to carbohydrate metabolism, rich in genes re-lated to pectinase, xylanase and carboxylcellulase. Therefore, the complex enzyme produced by A. japonicus PJ01 can be used in gizzard juice processing to achieve efficient enzymatic decapsu-lation.