Zero-trans shortening using palm stearin and rice bran oil

Several pilot-scale trials reported in this paper, using palm stearin-rice bran oil (PS-RBO) blends, obviously did not contain trans FA (TFA), whereas the commercial products were found to contain 18-27% TFA. The effects of processing conditions such as rate of agitation, crystallization temperature, and composition of the blends on the crystal structure of shortenings were studied. The products were evaluated for their physicochemical characteristics using DSC, X-ray diffraction (XRD), HPLC, and and FTIR techniques. The formulation containing 50% PS and 50% RBO showed melting and cooling characteristics similar to those of hydrogenated commercial "vanaspati" samples. Analysis of the FA composition revealed that the formulated shortenings contained 15-19% C-18:2 PUFA. Tocopherol and tocotrienol contents of the experimental shortenings were in the range of 850-1000 ppm with oryzanol content up to 0.6%. XRD studies demonstrated that the crystal form in the shortenings was predominantly the most stable beta' form, and there was less of the undesirable beta form.