Influence of Shape, Pre-treatment and Drying Air Temperatureon Quality of Dried Aonla

Abstract

Experiments were conducted to assess the effect of aonla shape, pre-treatment and drying air temperature on quality attributes of dried product. The aonla fruit was subjected to mechanical treatment to form three shapes i.e. spherical (whole pricked), cylindrical (15x35mm) and sheet (2 mm thickness) and were exposed to different pre-treatments i.e. untreated (UT), water blanching (WB), steam blanching (SB), blanching and sulphiting (B+S), sugar osmosis and salt osmosis prior to convective drying at temperature of 50, 60 and 70°C. The dried aonla (nearly 10% w.b) were analyzed for different quality attributes such as re-constitutional properties, vitamin C, colour and overall acceptability. The data indicated that re-constitutional properties, colour (L, a and b values), vitamin C and overall acceptability of dried aonla samples were significantly affected by the sample shape, pre-treatments and drying air temperature. The L, a and b values of sheet shaped aonla were close to the fresh sample resulting in minimum (6.43) colour change. The blanching + sulphiting pre-treatment samples witnessed minimum colour change and were at par to the salt osmosed samples. In comparison to untreated samples all the treated samples witnessed higher retention of vitamin C and overall acceptability. The maximum (74.49%) vitamin C was retained by the blanching + sulphiting pretreated cylindrical shaped sample dried at 50°C temperature whereas, the maximum consumer acceptance (98.15%) was recorded for sugar osmossed sheet shaped sample dried at 50°C.