Experimental edible composite coatings that can reduce postharvest Alternaria black spot in cherry tomatoes

Edible composite coatings based on hydroxypropyl methylcellulose (HPMC), commercial carboxymethylcellulose (CMC), CMC from rice stubble (CMCr) or sodium alginate (SA)?lipid were prepared with or without 2% of the food preservative sodium benzoate (SB) and evaluated against postharvest black spot caused by the pathogen Alternaria alternata on artificially inoculated organic cherry tomatoes during either incubation at 20?C and 80% RH for up to 13 days or storage at 5?C and 90% RH for up to 19 days,?followed by a shelf life period of 3 days at 20?C and 80% RH. Disease incidence and severity (lesion diameter) were determined during storage and the ?area under the disease progress stairs? (AUDPS) was calculated. In general, the addition of SB to the different polymeric matrixes, although did not reduce disease incidence during incubation at 20?C compared to non-amended coatings, significantly reduced black spot severity and AUDPS. Particularly, on fruit incubated at 20?C, the most effective antifungal coatings amended with SB for the control of black spot were those formulated with HPMC and CMCr (both with 10% total solid content (SC)), which reduced AUDPS values from 320 on uncoated control tomatoes to 175 and 210, respectively. On organic cherry tomatoes stored at 5?C, CMCr-SB coating was also the most effective, with AUDPS mean value for black spot at the end of the shelf life period of 120 while it was 360 on uncoated controls. Since CMCr was extracted from rice stubble, these results open a potential use to an important waste by-product in the rice industry, although further studies with other antifungal ingredients should be conducted to improve the performance this coating matrix. ? SourcesEffect of polysaccharide-based edible coatings amended with sodium benzoate on the control of postharvest black spot of organic cherry tomatoes caused by Alternaria alternataPattrathip Rodsamran1, Rungsinee Sothornvit1, Llu?s Palou2, Mar?a B. P?rez-Gago21Department of Food Engineering, Faculty of Engineering at Kamphaengsaen, Kasetsart University, 73140 Nakhonpathom, Thailand2Centro de Tecnolog?a Poscosecha CTP, Inst Valenciano Investigaciones Agr. IVIA, Carretera Moncada-N?quera, km. 4.5, 46113 Moncada, Valencia, SpainVIII International Postharvest Symposium,?Cartagena, Spain, 21-24 June 2016