Date of Graduation
Bachelor of Science
Conjugated linoleic acid-rich soy oil (CLARSO) has been shown to have numerous health benefits, including anti-obesity and anti-carcinogenic properties. This oil was previously used to produce CLA-rich margarine that provided the recommended daily value of CLA and showed physical characteristics similar to commercially available margarine. The objectives of this study were to produce CLA-rich shortenings and analyze their physical properties relative to commercially available shortenings and soy oil control shortenings and to produce CLA-rich chocolate bars and pastes by replacing a portion of the fat with CLARSO and compare the physical properties of these pastes/bars to controls made with either soy oil or traditional fats. The shortenings were prepared and their rheology, thermal behavior, solid fat content, and microstructure were determined and compared to the commercial samples. CLARSO, soy oil, and traditional fat blends were used to prepare bars/pastes. Rheology, firmness, and thermal behavior of the pastes and fracturability, hardness, and thermal behavior of the bars were determined relative to control samples. The CLA-rich shortening samples showed similar rheological properties to the commercial samples and exhibited more solid-like behavior than the soy oil control samples. The CLA-rich shortenings had higher solid fat content (% SFC) than the soy oil controls. CLA-shortenings released more heat upon crystallization and absorbed more heat upon melting than did the soy oil shortenings, indicating a comparatively higher crystalline fraction. However, the oil used did not affect the shortening crystallization temperatures and there was no observable difference in microstructure of the CLA and soy oil shortenings, likely due to palm stearin having a greater effect on the crystal structure than did the oil. The Crisco 4 commercial shortening had a more uniform crystal structure than did the experimental shortenings, likely due to the Crisco standardized industrial process. The CLARSO chocolate pastes/bars contained no additional saturated fat relative to soy oil controls but the pastes had more solid rheology and were firmer and the bars had a higher fracture force relative to soy oil controls. Relative to non-soy controls, CLARSO pastes had similar rheology and CLARSO bars had similar fracturability, despite containing less saturated fat. The fat crystals of all samples were in the same polymorphic form. Therefore, CLARSO has the ability to produce chocolate pastes/bars with similar physical properties as traditional products containing more saturated fat.
Agriculture, Food Science and Technology||Chemistry, Physical
Mayfield, Elizabeth Sarah, "CLA-Rich Soy Oil Shortening, Chocolate Paste, and Chocolate Bar Production and Characterization" (2015). Food Science Undergraduate Honors Theses. 3.