Fresh-cut sweet potato cubes coated with chitosan maintain quality.

Consumer demand for fresh-cut produce has been drastically increasing. Cutting sweet potatoes into different sizes or shapes adds value to this fresh product. However, this practice also accelerates deterioration in the product's quality and shortens its shelflife.

Based on preliminary studies, researchers at Louisiana State University found that a coating of chitosan could be used to prolong the shelflife of fresh-cut sweet potatoes for up to 17 days under refrigerated storage conditions. They were able to demonstrate the potential of the coating to preserve product quality and extend the shelflife of fresh-cut sweet potatoes. Their work involved evaluating sensory differences and consumer acceptability of the potatoes after up to 17 days of refrigerated storage. They also were able to identify the sensory attributes that determine the purchase intent of consumers for this product.

The scientists washed the sweet potatoes, then peeled and cut them into 13-mm cubes. The cubes were coated with 1% weight/volume (w/v) 470 kDa of chitosan in 1% acetic acid. They were stored in sealed plastic containers at 4 C for up to 17 days. Non-coated samples served as the controls.

One hundred consumers compared all of the samples with the controls to determine any sensory differences in terms of orange color, surface moistness, surface glossiness and surface odor. Consumers evaluated the samples' acceptability of appearance, color, odor, surface moistness, surface glossiness and overall liking, using a nine-point hedonic scale. Overall acceptance and purchase intent were evaluated using a binomial--yes/no--scale.

The investigators found that the coated samples stored for 17 days were not significantly different from the noncoated samples tested on the first day in terms of overall difference, orange color, surface moistness and surface glossiness, except for a surface odor caused by the odor of acetic acid. The coated 17-day samples were preferred less than the noncoated and coated samples tested on the first day, with a mean hedonic score of 5.2 and a 61.6% positive overall acceptance rating. The product's appearance and odor, but not surface glossiness, were attributes that determined consumers' purchase intent.

Further information. Witoon Prinyawiwatkul, Department of Food Science, Louisiana State University Agricultural Center, 11 Food Science Building, Baton Rouge, LA 70803; phone: 225-578-5188; fax: 225-578-5300; email: wprinyawiwatkul@agcenter.lsu.edu.