Beef tallow/high oleic sunflower oil shortenings produced by chemical interesterification optimized by response surface methodology ( RSM ): Effect of processing conditions on physical properties

Abstract

Response surface methodology (RSM) was used to obtain two shortenings(IEA and IEB) by chemical interesterification (CI) of beef tallow (BT) and higholeic sunflower oil (HOSFO) with melting points of 35.5C and 38.5C, higherOOO and SOO contents, and lower PPP, SOS, POS, and POP percentages than BT. The maximum percentage of HOSFO in the formulations and the opti-mum time, temperature, and catalyst concentrations to achieve the desiredphysicochemical properties for the shortenings were determined from themodel. The shortenings were characterized, and the effects of processing andstorage conditions were explored. HPLC/MS analysis showed that the monoand di-unsaturated triacylglycerols (TAGs) had unsaturated fatty acids at thesn-2 position. The changes in chemical composition due to the interesterificationprocess were mostly differences in percentages more than in the type of TAGspresent. IEA and IEB showed profiles of solid fat content versus temperatureand G’ values similar to those reported for soft and firm margarine, respectively.Under static cooling conditions, for BT, BA, BB, and IEB, the α-form was themain polymorph, whereas the β0-tendency increased with increasing temperatureand slow cooling rate. IEA crystallized in the β0-form between 20 and 32C.Under dynamic cooling conditions, nucleation was impeded at fast cooling rateand promoted at slow rate as evidenced by induction times of crystallization.Interesterification decreased the MP, increased the β0 tendency that lasted atleast 8 months at 25C, and improved the nutritional value of shortening makingthem suitable as trans-fat alternatives.