PHYSICO-FUNCTIONAL PROPERTIES OF PEANUT MEAL FLOUR AS AFFECTED BY PROCESSING METHODS

Abstract

Cold- and heat-pressed peanut meal cakes were milled, defatted and ground into fine powder and evaluated for proximate composition and functional food properties. Flours contained over 50% protein as compared with 25–45% protein in peanut meal cake. Cold-pressed peanut meal flour (CPMF) had a solubility profile similar to heat-pressed peanut meal flour (HPMF), with minimum and maximum solubility observed at pH 3.5–5.0 and pH 10.0 and higher, respectively. HPMF exhibited relatively high functional properties (emulsification, stability, oil and water absorption, whipping) compared with CPMF and commercial soy flour. Results suggest that flour obtained from peanut meal can be used as emulsifiers in different food formulations. Peanut flour could be a good source of food formulation for different food products in developing countries. Results show that high temperatures and long-time pressing affected physicochemical and functional properties of peanut flour. PRACTICAL APPLICATIONS Physico-functional properties of peanut meal cake, a waste product from peanut oil processing, were evaluated. Findings indicated that processing methods had significant effect on the physicochemical and functional characteristics of peanut flour. However, functional properties such as emulsification, heat stability, oil and water absorption, whipping and foamability were identified as useful attributes for application of peanut flour in a variety of food formulations. The protein content of peanut flour can serve as a cheap source of protein in developing countries where protein-energy malnutrition is prevalent. Recent research has suggested the possibility of using peanut oil as an alternative diesel fuel source. This is bound to increase the volume of peanut cake. Considering the high cost of conventional animal protein sources, the protein content of the cake could be tapped for human consumption. This research is environmentally friendly as it aims at converting waste product into functional food ingredients.