Innovia Films’ regular biaxially orientated polypropylene (BOPP) film promoted better shelf-life in granola cereal than its renewable and compostable film, a study finds.
The study published in the journal of Food Control looked into critical product characteristics and the environmental variables when designing packaging for granola cereal.
Researchers from the University College Cork in Ireland determined the water vapor transmission rate (WVTR) of packaging films at different environmental conditions and assessed shelf-life according to this.
“WVTR is a very important parameter for shelf-life determination of moisture sensitive food products, where shelf-life depends largely on the rates of permeation, which may occur quickly or slowly depending on the barrier property of the package,” the researchers wrote.
Films from UK firm Innovia Films used in the study included three variations of its biodegradable and compostable material NatureFlex (30 NK, 23 NM and 55 N913) and its BOPP product (Propafilm RGP 30).
BOPP trumps NatureFlex
“The BOPP package showed to be the best barrier to water in comparison to all the materials studied, and showing a similar performance to the control package,” the researchers wrote.
“The BOPP packaging film was also the least influenced film by relative humidity (RH), and temperature was the major influential parameter. For N913, NK and NM, the effect of temperature was much more pronounced at higher relative humidity.”
Under all conditions tested, predicted shelf-life for the BOPP packaging film was longer than the biodegradable and compostable products; nearly one week longer under accelerated conditions.
Findings showed that shelf-life under accelerated conditions (38°C and 90% RH) ranged from 13, 7, 3, and 2 days in BOPP, N913, NK, NM pouches, respectively. Under normal storage conditions of 20°C and 75% RH, predicted shelf-life was 271, 269, 90, and 33 days for BOPP, N913, NK and NM packages.
Granola samples of 30g were packaged into 8.5cm x 10cm pouches made from each different film, including a control from a commercial brand, and closed by heat sealing. Seven pouches of each film were tested.
Quality parameters such as moisture content, firmness, color and particle size distribution were measured throughout storage time. Sensory characteristics were also tested by a consumer panel using a hedonic scale at different sampling times over 15 days (days 0,3,8 and 15).
Source: Journal of Food Control
Published online ahead of print: doi.org/10.1016/j.foodcont.2012.05.045
“Quality by design for packaging of granola breakfast product”
Authors: ISM. Macedo, MJ. Sousa-Gallagher, JC. Oliveira and EP. Byrne