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ARS Home » Southeast Area » Fort Pierce, Florida » U.S. Horticultural Research Laboratory » Citrus and Other Subtropical Products Research » Research » Publications at this Location » Publication #311711

Title: Effect of edible coatings to preserve physico-chemical and sensory quality for fresh and cooked zucchini products

item BLANCO-DIAZ, MARIA TERESA - Instituto De Investigacion Y Formacion Agraria Y Pesquera
item Plotto, Anne
item Bai, Jinhe
item Narciso, Jan
item FONT, RAFAEL - Instituto De Investigacion Y Formacion Agraria Y Pesquera
item Baldwin, Elizabeth - Liz

Submitted to: Proceedings of Florida State Horticultural Society
Publication Type: Proceedings
Publication Acceptance Date: 11/3/2014
Publication Date: 12/31/2014
Citation: Blanco-Diaz, M., Plotto, A., Bai, J., Narciso, J.A., Font, R., Baldwin, E.A. 2014. Effect of edible coatings to preserve physico-chemical and sensory quality for fresh and cooked zucchini products. Proceedings of Florida State Horticultural Society. 127:152-157.

Interpretive Summary: Fresh-cut fruits and vegetables are popular for fresh consumption or as ready to cook items in the grocery stores, however they have a limited shelf life. Edible surface treatments that included edible films and/or solutions of antioxidants and antimicrobial agents were applied to sliced zucchini that was stored at different temperatures for both fresh and cooked consumption. Some treatments maintained color and firmness of the fresh-cut zucchini and firmness and flavor of boiled or steamed zucchini slices. These treatments extended the shelf-life and quality of cut zucchini.

Technical Abstract: This research studied different edible coatings for quality preservation of zucchini slices destined for fresh-cut consumption or for cooking. In the first experiment, antioxidants including calcium ascorbate (CAA), cysteine (CYS) or ethanol (ET) in edible coatings made from chitosan (CHIT), chitosan + glucose (CHIT+GLUC), whey protein concentrate (WPC), soy protein isolate (SPI), carboxymethyl cellulose (CMC), hydroxypropyl methylcellulose (HPMC) and soy bean oil (SB) were tested for effects on appearance and weight loss of the zucchini slices stored at 6 ºC and 20 ºC. In a second experiment, the best coatings (CHIT, HPMC, SPI and SB including CAA+ET as antioxidants) were tested for effects on color of fresh-cut zucchini slices stored at two different temperatures (6 ºC and 12 ºC). The effectiveness of CHIT, SPI, with or without antioxidants, was observed and HPMC and SB were eliminated from further testing. The use of antioxidants contributed to higher L* values (lightness) and hºab (hue angle) while reducing b* values (yellowness-blueness) as an indication of less discoloration than for water-treated controls. Finally, selected coatings were tested in a third experiment monitoring firmness and sensory quality before and after boiling, steaming, griddling, frying and microwaving. The use of CAA+ET, SPI and CHIT increased firmness of zucchini slices after boiling and steaming (CAA+ET and SPI only). SPI and antioxidants promoted an increase in overall color and visual linking for fresh samples, while SPI increased zucchini flavor, general flavor and overall liking of boiled and steamed samples. Both SPI and CHIT increased color quality and visual liking for microwaved zucchini samples.