MULTIFUNCTIONAL BIONANOCOMPOSITE FRUIT COATINGS

Sylvia Jung, Nancy Cui, Neethu Pottackal, Pulickel M. Ajayan, and Muhammad M. Rahman Rice University Houston, TX

Winner of an HP Workstation

Hunger and chronic under-nourishment impact over 800 million people in the world while a third of the food produced worldwide is wasted. This is especially evident with fresh produce, in which nearly 40 to 50% of crops grown are wasted. Reducing this waste has tremendous potential since even a 15% decrease could mean feeding 25 million more people.

Among commercial technologies, the most common method for preserving perishable produce is waxing — applying an artificial coating with fatty acid-based preservatives. But its lack of washability and the presence of potentially toxic compounds pose risks of adverse effects on human health and the environment.

The solution described here is a multifunctional, protein-based, conformal nanocomposite coating from readily available inexpensive or waste biomaterials. The coating offers a combination of properties that satisfies multiple preservation requirements such as material flexibility, edibility, washability, effectiveness, bio-degradability, and appearance.

The coating is primarily comprised of poly(albumen) protein derived from egg white and cellulose nanocrystal from wood pulp, along with various other biocompatible modifiers. Its synthesis starts with a combination of egg white protein, egg yolk, and glycerol that form a strong, edible film. Adding curcumin improves the antimicrobial and antioxidant properties that reduce microbial growth and allow the optimal exchange of gases in the microenvironment, decreasing oxygen and increasing carbon dioxide to maintain freshness. Cellulose nanocrystals further reduce the water and gas permeance.

Preservation studies revealed that after 8-11 days post-purchase, all the uncoated fruits showed enzymatic browning and decaying while the coated samples retained the appearance and firmness for over a week. In-vitro studies confirmed the edibility of the coating. In contrast to wax coatings, the coating is easily washable and provides a glossy visual appearance. Its ease of processing leads to its high potential for low-cost mass production.

The invention could capture the potential of the edible packaging market, estimated to reach $679 million by 2025. It has the potential to mitigate the 17 to 65% premium cost for organic produce and provide an affordable alternative for health-conscious consumers.

For more information, visit here .

Read a Tech Briefs Web-Exclusive Q&A with the team's lead researcher.


HONORABLE MENTIONS

Thermionic Transistor

John Read and Daniel Sweeney, Space Charge, San Diego, CA
The TWG application on a transport power configuration.

Direct thermal-to-electric energy conversion has the potential to replace internal combustion engines and turbines in nearly all electrical applications. The Thermionic Transistor uses electromagnetic force to create electrodynamic devices that can take almost any form factor, in nearly any environment.

For more information, visit here .


Aerodynamic Optimization of Wind Turbines

John Maris, Marinvent Corp., Quebec, Canada
The Enhanced Airfoil Performance Monitor.

The Enhanced Airfoil Performance Monitor directly monitors the local airfoil stress on each blade of a wind turbine and transmits conditions wirelessly and in real time to the turbine control station. It detects the smallest airflow perturbations and triggers alarms when thresholds are exceeded.

For more information, visit here .


Recycling of Lithium-Ion Electrodes

Donna Baek, Tedd Lister, and Luis Diaz Aldana, Idaho National Laboratory, Idaho Falls, ID
The process uses cheaper materials and fewer chemicals.

This process leaches cobalt and other valuable constituents from lithium-ion battery electrodes at room temperature with short reaction times. It uses inexpensive materials, can easily be scaled, and uses fewer input chemicals.

For more information, visit here .


Creating a Better Tomorrow by Repurposing Coal

PD Madden, Eco Energy International, Tustin, CA
Carbon-based material is converted into pure hydrogen.

This technology converts carbon-based material directly into pure hydrogen. The equipment is modular, allowing it to be located near end users. The process reduces greenhouse gases normally emitted from landfills and the burning of coal without harming the environment.

For more information, visit here .


See the rest of this year's winners:



Magazine cover
Tech Briefs Magazine

This article first appeared in the November, 2021 issue of Tech Briefs Magazine.

Read more articles from this issue here.

Read more articles from the archives here.