Effect of High Electric Field on Shelf Life of Strawberries

Abstract

An effort was made to elongate the shelf life of strawberries by the application of an alternating current (60 Hz) high electric field (HEF). An internal voltage as high as 174 V was measured in a strawberry by applying a 430 kV/m external electric field. Short treatment periods (0.5-1.5 h) with the HEF (430 kV/m) was found to reduce rotting (%) of the strawberries, but continuous HEF treatment was more effective to control rotting. Because continuous HEF treatment without packaging caused excessive weight loss, the strawberries were packed in polyethylene trays (OPS, P-11) and covered without sealing. The HEF was then continuously applied to the strawberries. Strawberries treated by continuous HEF for 6 days at 20°C and by electric fields of 0, 114, 172, 285 and 430 kV/m resulted in 80, 60, 50, 30 and 0% rotted samples, respectively. No differences were observed in surface color, pH, acidity and sugar contents between treated and non-treated samples.