Shelf appeal: Image analysis has greater focus than the untrained eye

Image analysis could be a effective way to determine quality loss in storage compared to visual inspection, according to researchers.

The researchers analyzed the effects of two different films on appearance and sensory qualities of muffins. They used image analysis, a relatively new technology that uses digital images to measure “morpho-colourimetric” features, or color and appearance changes, of food samples.

The team behind the paper published in the journal Food Research International used the method along with sensory analysis to determine the quality loss in muffins for 12 weeks or until the end of the suggested shelf life of the product.

They concluded that the cheaper polypropylene thermo-welding (PPTH) film performed similarly when compared to the second more expensive film, lacquered acrylic (PPAL).

Judging a muffin by its appearance

“The appearance of baked products is an important quality attribute related to product flavour and that influences the visual perceptions of consumers and hence, the potential purchase of the product,” the researchers wrote.

They said this new method provided more quantitative and less biased evaluation when compared to more common methods of visual perception, which could vary depending on the inspector.

“Image analysis easily and precisely estimated color and shape variations during the storage time,” they said. They added that color played a key part in consumer preference, with this becoming “homogeneous and flatter” during storage time.  

Film critics

Chemical and physical parameters such as lipid oxidation, loss of weight, water activity, dry matter and moisture were monitored in both packaging solutions, with the sensory profile method and image analysis measurements were performed during the 12 weeks of storage.

Across the two packaging solutions, the research found the main changes were to the outer surface characteristics of the bakery product.  

“Results coming from this preliminary research provided helpful advice for the bakery industry that will continue to use the cheaper PPTH being conscious of the similar performance of this film compared with the innovative PPAL,” they said.

Source: Food Research International

Published online ahead of print, doi.org/10.1016/j.foodres.2014.03.034

Use of Image Analysis to Evaluate the Shelf Life of Bakery Products”

Authors: O. Grillo, V. Rizzo, R. Saccone, B. Fallico, A. Mazzaglia, G. Venora, G. Muratore