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20221
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Subject: Chemistry × Author: Kapil, Sristhi × End date: 2022 × Start date: 2022 ×
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    Chemical modifications of paddy straw xylan for the preparation of sustainable bio films
    (Punjab Agricultural University, Ludhiana, 2022) Kapil, Sristhi; Mankoo, Ramandeep Kaur
    The present study involved valorization of paddy straw by conversion of its constituent polymer xylan and chemically modified xylans into biofilms. Paddy straw was found to contain 44% cellulose, 22% hemicellulose, 8% lignin, 21% extractives, and 5% silica. Hemicellulosic xylan (19.94%) extracted with 10% NaOH (85°C, 2.6 h) was chemically modified to acetylated (AX) and carboxymethylated xylan (CMX) followed by their structural characterization by FT-IR and NMR spectra. Xylan was found to show maximum antioxidant potential (Ascorbic acid equivalents value 7.6 at 10 mg/ml) and CMX showed highest antibacterial potential (Inhibition zone diameter of 31.80 and 29.75 mm against Bacillus and Pseudomonas, respectively). Biofilms were prepared by reaction of xylan/modified xylan (1 and 2%) with polyvinyl alcohol using eco-friendly and cheap crosslinker citric acid and glycerol as plasticizer. FT-IR and SEM analysis were performed for biofilms characterizations. 2% xylan biofilms showed maximum inhibition (94.25%) of DPPH radical at 4 mg/ml. 2% CMX biofilms exhibited maximum antibacterial effectiveness with diameter of zone of inhibition 33.5 and 30.5 mm against Bacillus and Pseudomonas, respectively. This may be due to large number of undissociated COO- ions (citric acid) in CMX biofilms which was evident from lesser cross-linking observed in their SEM images. 2% CMX biofilms also showed highest biodegradation (86.5%) which may be attributed to formation of ether bonds along with ester bonds which leads to their fast degradation. Owing to good bioactive properties of prepared biofilms, it was concluded that these can be appropriate material for food packaging by replacing synthetic plastics.