Document Type

Dissertation - Open Access

Award Date

2021

Degree Name

Doctor of Philosophy (PhD)

Department / School

Agricultural and Biosystems Engineering

First Advisor

Lin Wei

Abstract

Smart food packaging based on biosensors has been attracting more and more interest to the industrial community because of the concerns of food quality and safety. A food packaging with biosensor has a scope to enable real-time monitoring of microbial breakdown products of packaged foods. Furthermore, one of the biggest challenges in implementing biosensor for smart packaging materials is the development of bio-sensing active materials that can leverage their electrical, thermal, biodegradable and other functional properties. In this regard, nanocellulose-based activated carbon (NAC) nanocomposite was developed using the activated carbon and nanocellulose gel using the casting method with their different concentrations (15% to 50% of nanocellulose corresponding to 85% to 50% activated carbon). The developed NAC nanocomposites were electrically tested via cyclic voltammetry and results showed that 30% NAC nanocomposite consisted of good electrical properties compared to 30 and 50% of NAC nanocomposite for biosensor developments. Metal nanoparticle enriched natural biopolymer has attained significant attention in the research community, because they can create high specific surface area, adsorption capability, and gas sensing properties into polymer composite or nanocomposites. Different contents of AgNPs with 10-500 ppm were synthesized with 30% NAC nanocomposite and optimized their electrical properties. The results showed that AgNPs/NAC nanocomposite with optimum 450 ppm of AgNPs contained the good electrical properties for biosensor development. The biosensor developed with optimized AgNPs/NAC nanocomposite resulted in good sensitivity and selectivity to detect microbial breakdown products as a spoilage indicator. Ammonia (NH3) is one of the microbial breakdown products that released from protein rich food products (such as meat, fish, sea foods etc.) and had a good response in monitoring meat spoilage. The developed biosensor was utilized to monitor NH3, and the sensor showed good sensitivity over the range of 5-100 ppm and selectivity to detect the NH3. Biochar is one of the carbon-based materials that belongs a high specific surface area, highly porous structure, good stability, and cost-effectiveness over other carbon items (single or multi carbon nanotubes and graphene). The activated biochar (ABC)-based composite was developed with different ABC and polylactic acid (PLA) levels and the electrical properties of the developed ABC/PLA composite was determined via cyclic and differential voltammograms (CV and DPV). The results showed that 85% ABC/PLA composite has a good electrical property for biosensor development. To improve the gas sensing properties, 85% ABC/PLA composite was further synthesized with 450 ppm of AgNPs (v/v) and casted AgNPs/ABC/PLA nanocomposite. The biosensor was developed with casted AgNPs/ABC/PLA nanocomposite and tested for ammonia over the range of 5-60 ppm. The results revealed that the sensitivity of the developed biosensor increased as the concentrations of NH3 increased over the range of 5-60 ppm. An indicator with food packaging has the ability to monitor microbial contaminations in food products. A color indicator film was developed by a film casting method using an ultrasonic suspension of nanocellulose/chitosan blends doped with methyl red synthesis followed by PLA coating (named PLA/NCM film). The color modulation of the PLA/NCM films was processed via the colorimetric device and revealed considerable color changes (ΔEs) dependent on the meat spoilage. The PLA/NCM film changed its color upon exposure to different pH buffer solutions (2−10). The total viable microbial counts (TVC) and pH of the beef sample were determined, and the findings showed that the TVC and pH increased simultaneously depending on the state of the beef spoilage.

Library of Congress Subject Headings

Food -- Packaging.
Biosensors.
Nanocomposites (Materials)
Biopolymers.

Number of Pages

228

Publisher

South Dakota State University

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Rights Statement

In Copyright