Air speed and plastic crate vent-holes for wine grape quality during postharvest dehydration: commercial and laboratory studies

BACKGROUNDAirflow is an important issue to favor postharvest dehydration keeping wine grape quality. The aim of this experimental work was to analyze the grape quality during postharvest dehydration: (i) in a commercial facility ('fruttaia') by monitoring the efficiency of the ventilation system and (ii) at laboratory level, studying the influence of crate type and airflow direction. RESULTSIn the fruttaia, the airflow was provided by an air duct hanging from the ceiling, and by floor fans. A great gap in air speed from 0 up to 3.7 m s(-1) was measured in different sectors of the fruttaia, leading to a different weight loss and grape quality in crates, depending on crate stack height and sector. At the laboratory level, two tunnels, with exhaust or supply fans, were used and four crate types with different percentages of vent-holes were adopted. A decrease of about 5% delayed the weight loss rate depending on the type of crate, and the exhaust fan guaranteed a faster dehydration. CONCLUSIONThe results clarified the inefficiency of the commercial ventilation system in ensuring homogeneous grape weight loss in all crates. In addition, the exhaust fan guaranteed a more uniform air distribution around crates, and a slightly higher air speed. & COPY; 2023 Society of Chemical Industry.