BIOACTIVE BIOMATERIALS SYNTHESIZED VIA REACTIVE EXTRUSION FOR THE CONTROL OF WASTE FROM PACKAGED FOODS

Herskovitz, Joshua Ethan

BIOACTIVE BIOMATERIALS SYNTHESIZED VIA REACTIVE EXTRUSION FOR THE CONTROL OF WASTE FROM PACKAGED FOODS

Abstract

According to the FAO approximately 1.3 billion tons of edible food is wasted globally every year. To maintain product quality and reduce food waste, manufacturers often add preservatives, such as metal chelators and antimicrobials, to foods and beverages. Metal chelators effectively limit transition metal promoted oxidation and can enhance antimicrobial efficacy, yet consumers are increasingly demanding clean labels. In addition to food waste, plastic packaging waste presents a challenge to environmental sustainability of our food systems. Biopolymers provide a feasible solution to reliance on traditional packaging, but translatability of biopolymers into industrial settings proves difficult. The long-range goal of this work is therefore to develop non-migratory active packaging (permitting product preservation without preservatives) in a bioderived, biodegradable material utilizing an industrially relevant process through the creation of Reactively Extruded Active Compound Tethering (REACT) materials. Toward that goal, here we present, two synthesis mechanisms (radical grafting and oxazoline coupling) utilizing reactive extrusion to functionalize biodegradable poly(lactic acid) (PLA) with metal chelating ligands forming PLA-g-NTA and PLA.PBO.NTA respectively. Both oxazoline and radical grafted films indicated new alkyl stretches at 2919 cm-1 and 2860 cm-1 in ATR-FTIR spectra while PLA.PBO.NTA also showed a disappearance of the characteristic oxazoline band at 1640 cm-1 and the formation of a new band at 1530 cm-1 compared to control films. Advancing contact angle of PLA-g-NTA exhibited a decrease from 86.35o ± 2.49 to 79.91o ± 1.58 while PLA.PBO.NTA showed a decrease in receding contact angle from 54.46o ± 2.67 to 38.84o ± 2.66 compared to control films, indicating a change in surface hydrophobicity associated to surface functionalization. The functionalized films showed significant radical scavenging capabilities, ferric chloride chelation (PLA-g¬-NTA: 54.09 ± 4.19nmol/cm2 and PLA.PBO.NTA: 33.52 ± 2.74nmol/cm2) as well delaying essential nutrient oxidation, retaining greater than 44% and 47% of ascorbic acid respectively over the course of the study. As unintentional microbial growth in food products can account for up 25% of food loss globally, grafting of antimicrobials onto biodegradable materials through reactive extrusion represents another mechanism for overcoming food loss. Finally, the combination of nonmigratory metal chelating and antimicrobial bio-derived biodegradable packaging materials to form a bimodal preservation technique exemplifies next generation technologies for food packaging materials that support reduced food and packaging municipal solid waste. This work has further applications in biomedical devices and implants, nonfouling coatings, fabrics, soil remediation, and diagnostic industries in which functional biomaterials can advance scientific innovation, human health, and environmental sustainability.

Description

256 pages

Date Issued

2020-08

Keywords

Antioxidant; Biomaterials; Food Spoilage; Food Waste; Nonmigratory Active Packaging; Reactive Extrusion

Committee Chair

Goddard, Julie M.

Committee Member

Coates, Geoffrey
Worobo, Randy W.

Degree Discipline

Food Science and Technology

Degree Name

Ph. D., Food Science and Technology

Degree Level

Doctor of Philosophy

Types

dissertation or thesis