Document Type

Thesis - Open Access

Award Date

2022

Degree Name

Master of Science (MS)

Department / School

Dairy and Food Science

First Advisor

Srinivas Janaswamy

Keywords

biodegradable films, cellulose solubilization, high tensile strength films spent, coffee ground films, switchgrass films, UV blocking films

Abstract

Plastic packaging materials, which take more than 700 years to degrade, have polluted land, water, and the atmosphere. The consequent environmental and life hazards require attention to alleviate plastic concerns. Developing plastic-replacing materials could be a viable option. To this end, lignocellulosic fraction from inexpensive and widespread agricultural biomass switchgrass (SG) and biowaste spent coffee grounds (SCG) offer a possible solution, mainly to prepare biodegradable packaging films. Herein, lignocellulosic fraction from SG and SCG has been extracted, solubilized in ZnCl2 solution, and crosslinked through Ca2+ ions to prepare gels and cast biodegradable films. The SG was subjected to three extraction methods: 20% NaOH, 50% NaOH, and bleaching. The first two protocols retained traceable amounts of hemicellulose and lignin, and the latter yielded white cellulose. Films are made with each extract and the effect of Ca2+ ions (100, 200, 300, and 400 mM) on film properties such as color, thickness, moisture, water solubility, moisture update, water vapor permeability, tensile strength, %elongation, soil biodegradability, UV blocking, and radical scavenging activity has been studied. The influence of divalent cations Ca2+, Mn2+, Cd2+, Mg2+, Fe2+, Sr2+, and Ba2+, and biopolymers iota-carrageenan and chitosan on the white cellulose extract film properties xxi has also been studied. In the case of SCG films, four extract compositions (0.6, 0.8, 1.0, and 1.2 g) and Ca2+ ions (100, 200, 300, and 400 mM) have been studied. The results suggest that films possess high tensile strength, water vapor permeability, UV-blocking properties, and antioxidant activity and biodegrade within 45 days at 30% soil moisture. Overall, lignocellulose extract from switchgrass and spent coffee grounds displayed outstanding prospects has also been studied. In the case of SCG films, four extract compositions (0.6, 0.8, 1.0, and 1.2 g) and Ca2+ ions (100, 200, 300, and 400 mM) have been studied. The results suggest that films possess high tensile strength, water vapor permeability, UV-blocking properties, and antioxidant activity and biodegrade within 45 days at 30% soil moisture. Overall, lignocellulose extract from switchgrass and spent coffee grounds displayed outstanding prospects to develop biodegradable films and replace plastic packaging films.

Library of Congress Subject Headings

Cellulose -- Biodegradation.
Plastic films -- Biodegradation.
Packaging -- Biodegradation.
Biodegradable products.
Switchgrass.
Coffee grounds.

Number of Pages

199

Publisher

South Dakota State University

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Food Science Commons

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Rights Statement

In Copyright