(319c) Using Soybean Hull in Production of Paper-Based Gas Sensor for Food Packaging Applications

Using soybean hull in
production of paper-based gas sensor for food packaging applications

Soybean hull is a major co-product of soy
industry. It is the
seed coat of the soybean that is removed during the grinding process and
represents eight percent of the total weight of the biomass. Global annual
production of soybean hull is 18-20 million tons with approximately 10 million
tons being generated in USA in 2018. Some of the current applications of this co-product
include utilization of it as animal feed, in wastewater treatment, as dietary
fiber, and in herbal medicine. With the objective of soybean hull valorization
towards production of high value products, we have recently utilized processed
soybean hull as a novel binder in the fabrication of paper-based gas sensor for food safety. The production of this
novel binder requires only traditional, simple to apply, processing steps and
is environmentally friendly. The paper-based sensor was fabricated by coating
bentonite, soybean hull-based binder and a pH sensitive dye (bromocresol
purple) on paper in three different coat weights. Use of soybean hull product
as a binder decreases gas sensor production costs drastically comparing to any other
commercial binder, including polyvinyl alcohol (PVOH) which has been used in
our previous study. Furthermore, application of the soybean hull product can enhance
the sensor’s gas capture ability by providing high void volume. Lower binder
demand of bentonite makes the process even more cost-efficient. Bentonite
adsorbs volatile basic nitrogen compounds (VBN) which are metabolic by-products
of spoilage bacteria. The prepared samples of gas sensor were tested for their ability
to detect VBN through distinct color change from yellow to purple. For this
purpose, ammonium hydroxide solution with different concentrations were used. The highest sensitivity and
durability were 25 µL (upon exposure to 1mM ammonium hydroxide solution) and 24
hr (upon exposure to 100 µL of 5mM ammonium hydroxide solution), respectively
(Figures 1 and 2). These results are comparable to the ones obtained for the
PVOH-containing sensors.

Keyword: Gas sensor,
Food safety, Soybean hull