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Rice straw lignin was extracted via alkaline hydrolysis and structurally characterized using FT-IR and 1H NMR spectra. Ethyl acetate extract of acid solubilized lignin was found to contain p-coumaric acid, ferulic acid and caffeic acid as major phenolic acids which were isolated and characterized using spectral data. Amides of isolated phenolic acids were synthesized by their reaction with propyl and butyl amines using microwave irradiation and analysed using spectral studies. Phenolic acids and amides were evaluated for their effect on pollen germination and tube growth in pumpkin. Pollen tube length was significantly increased with N-butyl-3-(3, 4-dihydroxyphenyl) acrylamide and N-butyl-3-(4-hydroxyphenyl) acrylamide at 5 ppm concentration than the control. These results could be utilised in increasing pollen tube length of Cucurbita pepo while making interspecific cross between C. moschata and C. pepo in order to transfer hull-less character of C. pepo to virus resistant C. moschata genotypes. [ABSTRACT FROM AUTHOR]

Summary: The present study involved valorisation of rice straw by conversion of its constituent polymer xylan and chemically modified xylans into biofilms. Hemicellulosic xylan (19.94%) extracted with 10% NaOH (85 °C, 2.6 h) was chemically modified to acetylated (AX) and carboxymethylated xylan (CMX). Biofilms were prepared by reaction of xylan/modified xylan (1% and 2%) with polyvinyl alcohol using eco‐friendly and cheap cross‐linker citric acid and glycerol as plasticiser. 2% xylan biofilms showed maximum inhibition (94.25%) of DPPH at 4 mg mL−1 which was due to large number of free ‐OH groups (highest intensity of ‐OH absorption bands in FT‐IR spectra). 2% CMX biofilms exhibited maximum antibacterial effectiveness with diameter of zone of inhibition 33.5 and 30.5 mm against Bacillus subtilis and Pseudomonas sp., 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 the highest biodegradation (86.5%) which may be attributed to formation of ether bonds along with ester bonds leading 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. [ABSTRACT FROM AUTHOR]

Summary: The present study involved valorization of rice straw via production of biopolymeric films loaded with lignin and evaluation of their physical, mechanical, structural, antioxidant, antibacterial and biodegradable properties. Lignin (0.1%, 0.2% and 0.3%) loaded films were prepared by solvent casting method involving successful crosslinking between PVA, citric acid and lignin which was confirmed by ester bond formation at 1710 cm−1 in Fourier transform infrared spectrum. Scanning electron micrographs showed smooth surface in control and wavy surface in lignin film with no cracks. Lignin films possessed thickness, tensile strength and elongation at break in the range 0.127–0.142 mm, 22–31.38 MPa and 11.83–17.63%, respectively. Lightness value of films decreased while yellowness index increased as the level of lignin increased in films. Lignin loaded films showed potential antioxidant activity (51.4–74.6%) and antibacterial efficacy against Pseudomonas (diameter of inhibition zone 4.1 cm), thus suggesting their role in prevention of bacterial food contamination and organoleptic changes in food. The biodegradability tests showed that weight loss experienced by films after burial in soil was above 78.7% which offers a great advantage of these biopolymeric films over non‐biodegradable synthetic plastics, hence, these may be explored further as bioplastics to replace plastic wraps in food packaging. [ABSTRACT FROM AUTHOR]