Effect of Chemical Interesterification on the Physicochemical Characteristics and Fatty Acid Profile of Bakery Shortening Produced from Shea Butter and Fluted Pumpkin Seed Oil Blend

Abstract

The objective of this work was to evaluate the effect of chemical interesterification, as a modification process on the physicochemical properties and fatty acid profile of bakery shortening produced from a blend of Shea stearin and fluted pumpkin seed oil. The Shea nut oil was fractionated, and the solid stearin fraction blended with fluted pumpkin seed oil in the following ratios: 30:70, 40:60, 50:50,and 60:40 (Shea stearin: fluted pump seed oil), The blends were stabilized with recommended additives such as; distilled monoglyceride (E471) and preservatives such as; citric acid (E330), BHT (E321), homogenized by continuous stirring and crystalized by cooling at 17°C, then tempered at 23 – 25°C for 48h, to attain a stable polymorphic form, used as non-interesterified blends (NIEBs). Another set of 30:70; 40:60; 50:50; and 60:40 (Shea stearin: fluted pumpkin seed oil), were chemically interesterified with sodium methoxide (CH3ONa) as catalyst, crystalized, stabilized, and used as chemically interesterified blends (CIEBs).The chemical properties, physical characteristics (including solid fat content), and the fatty acid profile of all the chemically interesterified (CIEB) and the non-interesterified (NIEB) samples were determined. There was no significant (p>0.05) change in the peroxide value, iodine value, and the refractive index of NIEBs and there corresponding CIEBs. The acid value, free fatty acids, slip melting point, density, and solid fat content were significantly (p<0.05) reduced after interesterification. Interesterification caused rearrangement of triacylglycerol species, resulting in increased unsaturated fraction and reduction in the saturated fraction. Interesterification gave fats with wide plastic range suitable for bakery fats, icing-shortening, filler fats, and all-purpose shortenings.