2023-05-14 14:59:49
Avocados are becoming more and more popular: whether spread on toast, in guacamole or in salads, they are the star ingredient of many meals. However, this is a very delicate fruit, going from firm-textured green to soft-textured brown in the blink of an eye.
Now, researchers from the American Chemical Society have presented a chitosan-based coating that preserves them for longer. The team has also developed an imaging technique to quickly predict expiration, as has been published in the journal ‘ACS Food Science & Technology’.
To tell if avocados are ripe, most people squeeze them gently., and a little fluffiness indicates that they are already in that state. Growers perform similar evaluations to determine which avocados can withstand transportation to grocery stores. Despite these tests, some break down prematurely.
For this reason, researchers have developed techniques to delay maturation, using compounds such as 1-methyl-cyclopropene (1-MCP). More recently, studies have shown that naturally occurring chitosan –a biomaterial derived from the exoskeletons of mollusks– imparts antimicrobial activity when applied as a coating to fruits, including avocados.
So Angie Homez-Jara, Angelica Sandoval-Aldana, and their colleagues wanted to compare the effectiveness of the two preservation methods on the quality and shelf life of avocados. Researchers treated commercially ripe Hass avocados, the most cultivated variety worldwide, with gaseous 1-MCP or with aqueous solutions containing different concentrations of chitosan.
Mimicking realistic shipping conditions, treated and untreated avocados were chilled to 41 degrees Fahrenheit for 21 days and then moved to room temperature to simulate a grocery store environment, until they rotted.
The untreated samples and those treated with 1-MCP or with a 1 percent chitosan-based coating were at their optimum ripening point for 6 days. Fruits treated with a 1.5 percent chitosan-based coating were at their optimum for 12 days.
However, these samples also had a uneven firmness when ripeas well as green and purplish spots on the skin, which the researchers say shows that the chitosan coating could be improved in the future.
Throughout the study, the researchers also imaged the entire surface of the fruits with hyperspectral cameras in the visible and near-infrared spectrum.
They then compared the reflectance data from the images with the firmness, skin color, oxygen consumption and weight loss of the avocados, using various computer models.
More society news
Two machine learning models better explained the changes that occurred during avocado ripening and could predict their remaining shelf life. The researchers say their chitosan-based coating and prediction technique could help improve the shelf life and quality of avocados for sale.
#Science #finds #formula #avocados #longer