An innovative technique for extending shelf life of strawberry: Ultrasound

Ultrasound is one of the newest nonthermal methods to extend shelf life of fresh fruits during storage. The effectiveness of ultrasound depends on wave frequency, power and treatment time. The present study was designed to determine the effect of different ultrasound powers (30 W, 60 W, 90 W) and treatment times (5 min, 10 min) on quality of strawberry. Oxygen concentration inside packages of strawberries which treated with 30 W and 60 W ultrasound powers were higher than 90 W and control (CNT) groups. A sharp increase in CO2 release rate was observed for the CNT and 90 W treatments during the storage. Attributes such as pH, total soluble solid content and color for the 30 Wand 60 W treatments were better than CNT and 90 W treatments. Decay incidence analysis confirmed that all ultrasound treatments were effective to reduce mold growth. The 30 W and 60 W treatments maintained better textural properties compared with 90 Wand CNT groups. FT-NIR analysis was used to quantify water and sugar content of strawberries. As a result, it was concluded that ultrasound power as high as 90 W resulted in detrimental effects on strawberry quality, while power levels between 30 W and 60 W had improved quality and can be used to extend shelf life of strawberry. (C) 2012 Elsevier Ltd. All rights reserved.