Phase behavior studies of edible lipids and their industrial applications.

摘要

Due to the adverse affect of consuming trans fats, the presence of trans fats in edible oil products such as a shortening is under fire. However the removal of trans fats without increasing the level of saturated fats is not trivial as trans and saturated fats tend to have high melting points and contribute to the formation of a solid crystal network. Therefore a series of comprehensive and extensive phase behavior studies of canola and other vegetable oil based shortenings were developed to design a zero trans, lowered saturates shortening with hardness commensurate that of a commercial product which utilizes the structure enhancing properties of specific TAGs.;Given this observation, the canola shortening system initially investigated was enriched with pure PSS as well as PSS as a component of fully hydrogenated canola and cottonseed oil and the effect of PSS was observed. It was found that by careful blending of fully hydrogenated canola and cottonseed oils one could increase hardness whilst limiting total added saturated fat. The increase in hardness as seen on the lab scale was also observed for shortenings produced at the pilot plant scale.;In an effort to further enhance the crystal network formed, the processing conditions and tempering were varied. The increase in hardness due to the careful blending of raw materials could be further enhanced given optimal processing and tempering parameters. Finally, the PSS enriched shortenings were made into cream icings and demonstrated greater suitability for icings than shortenings without enrichment.;Binary shortening systems containing fully hydrogenated canola, cottonseed, lard, palm, soybean or tallow in soybean oil were investigated in an attempt to drastically alter the molecular composition of the shortening samples utilizing commercial raw materials. The composition affected the growth mode of the crystal network as well as SFC, polymorphism, hardness and the enthalpies of crystallization and melt. SFC was found to be unpredictive of final hardness, while polymorphism could be explained by changes in the molecular ensemble. The final physical properties of the shortenings seemed to be significantly influenced by amounts of the TAGs PSS, PSP, or PPS, and not just SSS.