Improving Sandiness Of Beef Tallow-based Shortening By Chemical Interesterification

Edible beef tallow is widely using in baking industry. Aroma and flavor of food products used beef tallow shortening will be enhanced by baking. But beef tallow shortening is easy to undergo sandiness or graininess and their physical properties will also be changed when temperature fluctuates during handling, storage or transportation. The purpose of this article is to deal with the graininess crystals in beef tallow shortening, discuss the essential reasons, and solve the graininess defect from base stocks.The fatty acids , triacylglycerols (TAGs) , polymorphism,crystallization kinetics and morphology of the grainy crystals and surrounding materials in the edible beef tallow shortening were studied. The saturated fatty acids in grainy crystals increase slightly.TAGs results showed that the grainy crystals changed greatly compared with their surrounding materials. The contents of low melting TAGs POL, POO and SOO /SSL descended, while the contents of symmetrical higher melting point TAGs POP, POS and SOS rose.The results of X-ray diffraction (XRD) showed that the crystal form of grainy crystals wasβform. The results of isothermal crystallization kinetics indicate that the crystallization rate of grainy crystals was slower than surroundings. The morphology of grainy crystals are also coarser. It can be confirmed that lower melting point TAGs will melt when the temperature rises, which will provide enough spaces for the symmetrical higher melting point TAGs to move close and form the crystal nuclei.Long hydrocarbon chain in TAGs embedded in differerent crystal lattice and forming differerent polymorphism. Symmetrical TAGs(POP,POS,SOS)agglomerates and forming the bigger and sheetβpolymorph,reduce the crystallization rate of fat system.A decteased nucleation is usually accompanied by an increase in crystal growth.the crystal agglomerates forming the bigger crystal clusters.the graininess crystal will be formed.in shortening.These results show that higher melting TAGs are one of the key factor for the formation of granular crystals in shortening.It was studied beef tallow (BT)and low erucic acid rapeseed oil(LEAR) by chemical interesterification (CI)to reduce the amount of symmetrical TAGs(POP,POS,SOS)solving the graininess in beef tallow shortening. The SFC profiles of CI products is suitable for baking shortenings. High melting point TAGs of The blends of BT and LEAR(80:20 w/w) reduced lagerly in follow reaction conditions:reaction temperature 60℃, methanol sodium 0.6%(w/w),for 90min.The CI products stable inβ′form and the morphology of crystals appear less densely packed. So it is satisfied the solid shortening stock.It was used distill monostearate, Span 60 and lecithin as emulsifiers. The ratio of distill monostearate, Span 60 and lecithin is 0.1:0.45:0.45. The best constitute of shortenings is that: the blends of BT and LEAR(80:20 w/w) CI at follow reaction conditions:reaction temperature 60℃, methanol sodium 0.6%(w/w),for 90min,and then add 1% emulsifiers to the products of CI.and it can fulfill the function of shortening. Shortening according to this ratio prepares in the laboratory was saved in winter ( temperature range 5～20℃) for 2.5 months, there was no visible grainy crystals existing in the product. Baking products has the similar sense, special volume and hardness using the prepared shortening product compared with quantong shortening obtained from market.