Abstract
The process variables high hydrostatic pressure (HHP; 100–500 MPa), sucrose concentration (30–70 °Brix), immersion time (5–9 h) and immersion temperature (30–70 °C) were optimised to yield maximum water loss (WL), minimum solid gain (SG), minimum water activity (a w) and minimum browning index (BI) during osmotic dehydration (OD) of banana slices (Musa cavendishii) pretreated by HHP using response surface methodology. The pressure-treated samples showed significantly higher WL and SG during OD (p < 0.05), which was attributed to the rupture of cell wall with applied pressure, making the cells more permeable, also evident from the scanning electron micrographs of the banana tissue. The optimised operating conditions were: HHP of 200 MPa for a dwell time of 5 min at room temperature (26 °C), sucrose concentration of 60 °Brix, immersion time of 5 h and immersion temperature of 40 °C. A study of the concentration profiles during OD revealed no appreciable increase in SG and WL after 4 h; hence, immersion time was reduced to 4 h. The optimised product developed was dried to a moisture content of 15 % (wet basis) in a dehumidified air dryer at an air temperature of 40, 55 and 70 °C with a fixed air velocity of 3.8 m/s and relative humidity maintained at 20 %. The final dried product was analyzed for total soluble solids content, BI and a w. A drying temperature of 55 °C was found to give superior quality OD banana slices in terms of reduced bulk, improved flavour, decreased a w (<0.60), and reduced dehydration time and energy using HHP as a pretreatment.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call