Hydrocolloid-based Packaging Films — Alternate to Synthetic Plastics

547-559An alternate approach to non-biodegradable synthetic plastics is packaging films based on hydrocolloids and their derivatives. They are available in plenty from highly renewable natural resources and their total biodegradability makes them ecofriendly. Blending as well as graft copolymerization of synthetic monomers onto natural polymers after additional means of preparing biodegradable packaging films

Arabinoxylan from <i>Cryptocarya wightiana </i>Bark

1287-1288A homogeneous arabinoxylan (Ara-Xyl in 1.05:1 ratio) has been obtained from the major water soluble fraction of Cryptocarya wightiana bark gum by employing gel filtration on Sephacryl S-400 and SE-HPLC techniques. Methylation of the pure polysaccharide followed by GLC-MS analysis reveales a highly substituted 1,4-linked xylan backbone

Groundnut carbohydrates - a review

This review summarises comparative studies conducted here and elsewhere on the various carbohydrate fractions of groundnut. Mono- and oligosaccharides, starch, xylan, glucomannan and cellulose were some of the fractions isolated and characterised. The xylan was shown to be highly branched, having a backbone of &#946;-1,4-linked D-xylopyranose residues and further substituted at C-2 (9.6%) and C-2, C-3 (15.6%). The glucomannan, containing more of glucose than mannose (mol ratio, 4:1) was a linear &#946;-1,4-linked polymer. Investigations using scanning electron microscope of enzymically digested groundnut starch revealed several types of 'pitting' on the starch granular surface. The effects of processing and germination on the make up of groundnut carbohydrates were also investigated. Incubation of the defatted groundnut flour (GNF) with a partially purified hemicellulase preparation indicated almost complete breakdown of the pentosan constituents and resulted in a greater extraction (over 90%) of proteins from GNF

Carbohydrate composition of groundnuts (Arachis hypogea)

The proximate composition of defatted edible groundnut flour, processed and unprocessed, has been determined. The flour contains about 38% total carbohydrates of which oligosaccharides account for 18%, starch 12.5%, hemicelluloses A and B 0.5 and 3.5% respectively and fibre (cellulose) 4.5%. Sucrose 13.90 and 14.55%, raffinose 0.89 and 0.92%, stachyose 1.56 and 1.60%, and verbascose 0.41 and 0.42% represent the oligosaccharide fractions (from 70% alcoholic extract) of unprocessed and processed flour, respectively. In addition the unprocessed flour also contained glucose 0.80% and fructose 0.41 % along with two unidentified spots 0.70%. Hemicellulose A consisted of glucose, arabinose, and xylose (4:0.5:0.1) whereas hemicellulose B had galacturonic acid, glucose, galactose, arabinose and xylose (1:4:1:12:6). The fibre fraction on hydrolysis yielded predominantly glucose with only traces of galacturonic acid and rhamnose. The presence of verbascose and xylose in groundnuts has not been previously reported

Structural investigations on two hemicellulosic polysaccharides from groundnut (Arachis hypogea) seed endosperm

A highly branched xylan and a linear, &#946;-d-(1&#8594;4)-linked glucomannan are the two hemicellulosic components isolated from the endosperms of groundnut (Arachis hypogea). Electrophoretic, sedimentation, and sugar analysis indicate the polysaccharides to be fairly homogeneous. The O-methyl derivatives of the polysaccharides were analysed, after reduction and O-acetylation, by gas-liquid chromatography and g.l.c.-mass spectrometry. 2,3,4-Tri-O-methyl-d-xylose (3.6 mol), 2,3-di-O-methyl-d-xylose (21.0 mol), 3-O-methyl-d-xylose (2.8 mol), and d-xylose (4.2 mol) were detected in the xylan, whereas 2,3,4,6-tetra-O-methyl-d-glucose and/or mannose (1.6 mol), 2,3,6-tri-O-methyl-d-mannose (5.6 mol), and 2,3,6-tri O-methyl-d-glucose (21.2 mol) were found in the glucomannan. Periodate and Smith-degradation studies substantiate the results of methylation analysis on the xylan. A glucose: mannose ratio of 3:1 for the glucomannan, however, suggests that this fraction may be an aggregate of true glucomannan and glucan or degraded cellulose

Characterization of chito-oligosaccharides prepared by chitosanolysis with the aid of papain and Pronase, and their bactericidal action against Bacillus cereus and Escherichia coli

Papain (from papaya latex; EC 3.4.22.2) and Pronase (from Streptomyces griseus; EC 3.4.24.31) caused optimum depolymerization of chitosan at pH 3.5 and 37 °C, resulting in LMMC (low molecular mass chitosan) and chito-oligomeric–monomeric mixture. The yield of the latter was 14–16% and 14–19% respectively for papain- and Pronase-catalysed reactions, depending on the reaction time (1–5 h). HPLC revealed the presence of monomer(s) and oligomers of DP (degree of polymerization) 2–6, which was also confirmed by matrix-assisted laser-desorption ionization–time-of-flight MS. Along with the chito-oligomers, the appearance of only GlcNAc (N-acetylglucosamine) in Pronase-catalysed chitosanolysis was indicative of its different action pattern compared with papain. Fourier-transform infrared, liquid-state (13)C-NMR spectra and CD analyses of chito-oligomeric–monomeric mixture indicated the release of GlcNAc/GlcNAc-rich oligomers. The monomeric sequence at the non-reducing ends of chito-oligomers was elucidated using N-acetylglucosaminidase. The chito-oligomeric–monomeric mixture showed better growth inhibitory activity towards Bacillus cereus and Escherichia coli compared with native chitosan. Optimum growth inhibition was observed with chito-oligomers of higher DP having low degree of acetylation. The latter caused pore formation and permeabilization of the cell wall of B. cereus, whereas blockage of nutrient flow due to the aggregation of chito-oligomers–monomers was responsible for the growth inhibition and lysis of E. coli, which were evidenced by scanning electron microscopy analysis. The spillage of cytoplasmic enzymes and native PAGE of the cell-free supernatant of B. cereus treated with chito-oligomeric–monomeric mixture further confirmed bactericidal activity of the latter. Use of papain and Pronase, which are inexpensive and easily available, for chitosanolysis, is of commercial importance, as the products released are of considerable biomedical value