Submitted to: International Wheat Quality Conference
Publication Type: Abstract Only
Publication Acceptance Date: 5/26/2005
Publication Date: 5/28/2005
Citation: Mohamed, A., Gordon, S.H. 2005. Thermal properties of transglutaminase-crosslinked wheat gluten and poly (lactic acid) blend [abstract]. International Wheat Quality Conference. p. 225.
Technical Abstract: Transglutaminase (10 units) was used to crosslink (XL) 10g of wheat gluten in 2L 0.1 M Tris-HCl, pH 7.5. The suspension was stirred for 24 hours at 40ºC and freeze-dried. Different ratios of Poly-Lactic acid (PLA) and XL wheat gluten (XLG) were blended in a Brabender mixer at 180ºC. The blends (95:5, 80:20, 70:30, and 50:50 PLA:XLG) were tested using Modulated Differential Scanning Calorimetry (MDSC) where 45-50 mg were heated from 20 to 250ºC at 10ºC/min. The samples were subjected to a number of heating and cooling cycles. The MDSC data of neat PLA showed a glass transition of (0.46 J/g/ºC) followed by crystallization at 156ºC with 29.9 J/g, and melting at 117.8ºC with 28.7 J/g transitions. The primary DSC thermogram of XLG showed one Tg (0.45 J/g/ºC). Relative to the amount of PLA blends required, cycles before PLA were no longer able to crystallize. The 95:5 PLA:XLG required 130 cycles; 80:20 and 70:30 needed 8 cycles; and 50:50 didn’t crystallize after 4 cycles. The activation energy (Ea) was calculated using the crystallization transition. The increase in the cycle number caused an increase in Ea.