Starch Derivatives in Coating Formulations as Carriers of a Biocontrol Yeast, Candida sake, to Control Fungal Decay on Grapes

摘要

The biocontrol agent (BCA) Candida sake CPA-1 has proven to be effective against Botrytis cinerea, the fungus causing grey mold in many fruits. The performance of this yeast could be improved if applied in combination with edible coatings. Several combinations of starch derivatives and cell protectants were tested to obtain water-dispersible granular biocontrol products (BCPs) of C. sake. Those with better shelf life and stability were: BCP1 based on potato starch and pre-gelatinized potato starch, and BCP2 based on maltodextrins, sucrose, and skim milk powder. BCP1 and BCP2 were applied under controlled conditions on table grapes (Moscatel variety) and the study of the population dynamics of C. sake was carried out. Fruit visual appearance and weight loss were also examined. In each case, a progressive increase in the C. sake population took place after 1,2 and 4 days of application, with a significantly greater increase in BCP1 formulations after 4 days. Grapes with both BCP formulations exhibited a slightly higher gloss than the uncoated control, although no marked differences in the fruit appearance were observed. After 7 days, considerable changes were observed in fruit appearance, but these changes were less marked in the case of the coatedgrapes. The lowest weight loss was observed with BCP2 although few differences were detected between formulations.