ROASTING TIME-TEMPERATURE OPTIMIZATION FOR PREPARATION OF PEANUT BUTTER AND STUDY ON ITS SHELF LIFE

Abstract

The objective of this study was to develop peanut butter from roasted and grounded peanut. Raw peanut of variety 'Jayanti' (Type-Spanish bunch) was collected from Sunsari district, Dharan and were roasted at three different temperatures (130°C, 140°C and 150°C) for three different time periods (10, 15 and 20 min) to optimize the process of butter making with 9 different samples. The raw peanut was sorted prior to roasting and grinding. The roasted-ground peanut paste was obtained in which ingredients namely lecithin (1%), salt (1%), sugar (1%) and oil (3%) were added. Oil was added to give final fat content of the butter not more than 55 % by weight. The peanut butter was then subjected for sensory analysis, proximate analysis and shelf life evaluation. Based on the sensory evaluation, significantly best (p<0.05) peanut butter can be produced from preparing peanut paste by roasting peanut at 150°C for 10 min. The proximate analysis of peanut butter showed that it contained moisture content, fat content, total carbohydrate, crude fiber, crude protein, ash content and energy value of 5.8±0.04%, 52.70±0.45%, 19.28±0.05%, 5.47±0.5%, 38.67±0.07%, 5.67±0.80% and 641.5±3.57 kcal respectively. The shelf life of the peanut butter stored at ambient temperature (room temperature) was found to be 11 days, but the butter stored at refrigerated temperature was not spoiled by rancidity throughout the period of storage (55 days).