Fractionation and Structural Characterization of Hemicellulose from Steam-Exploded Banana Rachis

Abstract

Banana production in tropical countries generates significant quantity of waste. Biorefinery of food waste biomass into cellulose, hemicellulose, lignin or pectin macromolecules have grown interest in recent scientific literature. In this paper, hemicellulose from banana rachis (Musa cavendish) was extracted by steam explosion at three severity levels (2.97, 3.57 and 3.78) and was further fractionated by graded ethanol precipitation method (15%, 60% and 80%). The recovered hemicelluloses sub-fractions (H1, H2 and H3) were characterized for their chemical composition and structural features by HPSEC, TGA/ DTG, FTIR, 1H and 2D NMR techniques. The hemicellulose extraction yield increased with the severity level and treatment duration. The average molecular weight of the extracted hemicellulose macromolecules decreased from H1-60% ethanol hemicellulose sub-fraction with 143 790 g/mol, followed by H3-60% ethanol hemicellulose sub-fraction with 110 841 g/mol and finally H2-60% ethanol hemicellulose sub-fraction with 61 404 g/mol. The H1-60% ethanol hemicellulose sub-fraction extracted during the steam explosion at the lowest severity level showed the largest molecular weight and exhibited rather a high arabinose/xylose ratio and uronic acid content. Structural analysis revealed that hemicellulose from the 60%-ethanol hemicellulose sub-fractions were mainly arabino-glucuronoxylan (AGX). However, chemical analysis also revealed significant contents of co-extracted residual lignin. Although the ethanol fractionation helped at lowering the lignin content in the 60%-ethanol hemicellulose sub-fractions (20.1% in H2-60%, 24.0% in H1-60% and 28.0 in H3-60%) relatively to 80%-ethanol hemicellulose sub-fractions, additional purification step was still required to improve the quality of the extracted hemicellulose sub-fractions (purity and coloration). Nevertheless these results proved that steam explosion was an effective technique for the extraction of high molecular mass AGX hemicellulose macromolecules from banana rachis residues.

Structure and In Vitro Fermentation Characteristics of Polysaccharides Sequentially Extracted from Goji Berry (Lycium barbarum) Leaves

“…More detailed structure information of polysaccharides obtained by NMR is presented in Figure according to the 4.72 ppm signal peak of D 2 O as the reference peak . All signal peaks of GalA were observed in the spectra of CA (H1 4.98 ppm, H2 3.62 ppm, H3 3.94 ppm, H4 4.07 ppm, and H5 4.35 ppm) .…”

“…The scanning frequency range was 4000−400 cm −1 . To obtain the 1 H NMR information, 10 mg of each sample was dissolved in 500 μL of D 2 O to replace exchangeable protons three times and then each sample was dissolved in 500 μL of D 2 O (only SC-I cannot be completely dissolved in 20 Data were analyzed by MestReNova 14 software. Atomic Force Microscopy.…”

“…The scan numbers of 1 H NMR, 1 H– 1 H COSY, TOCSY, HSQC, and HMBC spectra are 32, 16, 32, 108, and 96, respectively. Chemical shifts were based on shifts of HDO (4.72, 298.15 K) . Data were analyzed by MestReNova 14 software.…”

Recovery of xylan from Acacia mearnsii using ultrasound‐assisted alkaline extraction

“…This weight loss could be attributed to the loss of moisture and volatile compounds from the samples. 47 The samples further C Gufe, MS Thantsha, S Malgas Original Article: Recovery of xylan from Acacia mearnsii 983 underwent a second but massive loss in weight between 200 and 400°C (Fig. 5(a)).…”

Valorization of byproducts from tropical fruits: A review, Part 2: Applications, economic, and environmental aspects of biorefinery via supercritical fluid extraction

“…Moreover, other carbohydrates with bioactive activity have also been studied (i.e., α‐(1→6)‐ d ‐glucan). Also, polysaccharides from banana rachis have been fractionated into cellulose, hemicellulose lignin, or pectin by steam explosion (Tiappi Deumaga et al., 2020).…”