Submitted to: World Congress of International Union of Food Science and Technology
Publication Type: Proceedings
Publication Acceptance Date: 9/18/2006
Publication Date: 9/18/2006
Citation: Gharst, G., Clare, D.A., Davis, J.P., Sanders, T.H. 2006. Transglutaminase Effects of the Rheological Characteristics of Peanut Flour Dispersions. World Congress of International Union of Food Science and Technology. Interpretive Summary:
Technical Abstract: INTRODUCTION: Peanuts (Arachis hypogaea L.) are a stable food commodity around the world. In the last few decades, peanut flour (PF) has been used as a food ingredient. Previously, microbial transglutaminase(mTGase), an enzyme that catalyzes protein cross-linking via acyl-transfer reactions (1) was shown to modify functional properties of food systems including viscosity, solubility, and water holding capacity. In previous work, others had already noted increased gel strength for both whey and soy upon treatment with mTGase(2, 3). OBJECTIVE: The objective for this study focused on characterization of rheological properties of PF dispersions crosslinked with mTGase. METHODS: Commercial PF, light roast; 12% fat (LR12), soy flour, toasted; 2% fat (SF), and LR12 containing amidated pectin (AP) at a concentration of 0.5% (w/w) were dispersed in deionized water. All dispersions were adjusted to pH 8.0. Dispersions containing mTGase and non-treated control samples were then incubated at 37 degree C with agitation for six hours before rheological analysis. Dispersions were heated from 40 degree to 90 degree C at 1 degree C/min and subsequently cooled to 40 degree C while continuously monitoring rheological changes. Large strain measurements were conducted under continuous rotation at a shear rate of 50 1/s. Protein profiles were visualized after SDS-PAGE followed by staining with colloidal coomassie blue and protein concentrations determined by BCA assay methods. RESULTS: PF dispersions exhibited low solubility that was improved by addition of AP (0.5% w/w). PF and PF(AP) test samples demonstrated higher apparent viscosities upon heating as compared to soy. However, SF was more viscous at the beginning of these measurements. LR12 and LR12(AP) dispersions treated with mTGase showed a decrease in apparent viscosity as compared to non-treated samples. We attributed these differences to protein polymerization as supported by SDS-PAGE electrophoresis. CONCLUSION: In reporting the first rheological effects of mTGase on PF dispersions, this study could aid in texture optimization of food products containing PF.