Effects of processing conditions and packaging material on the quality attributes of dry-roasted peanuts

Five different processing conditions of raw shelled unblanched peanuts were investigated. The first two treatments involved soaking the peanuts in tap water for 10 and 30 min respectively, then mixing thoroughly with dry NaCl before roasting. Another two treatments involved soaking the peanuts in saturated brine solution for 10 and 30 min respectively before roasting. Unsalted roasted peanuts served as the control. Packaging and storage studies were carried out by packaging the differently treated dry-roasted peanuts in four different packaging materials and storing them under three different relative humidities for 3 months at ambient temperature. Proximate composition, NaCl content, peroxide value and thiobarbituric acid value were determined and sensory evaluation tests were carried out. Salting was found to improve the taste, flavour and overall acceptability of dry-roasted peanuts but had no effect on shelf-fife. Peanuts treated in saturated brine solution for 30 min before roasting were the most preferred. The control packaging material, 18 mum transparent polyethylene, was found to be inadequate for protecting the quality attributes of dry-roasted peanuts, with mould growth being observed on the 42nd day of storage at 80% relative humidity. However, acceptable results were obtained with 45 mum transparent polypropylene. The mean sensory scores and objective tests were found to be negatively correlated. (C) 2002 Society of Chemical Industry.