Formation of secondary structures in protein foams as detected by synchrotron FT-IR

FT-IR analysis was used to study the effect of temperature on foaming Novatein, a semi-crystalline thermoplastic biopolymer based on blood meal. Foaming was caused by rapid expansion of steam, ammonia and CO2 from urea hydrolysis, leading to expansion ratios between 3.8 and 5.6. Plasticisers were more concentrated near the bubble surface, suggesting some tri-ethylene glycol accumulation. The beta-sheet fraction in Novatein was not influenced by foaming or thermal treatment, but their distribution was influenced by bubble growth. beta-sheets agglomerated near the bubble surface and was more pronounced at higher temperatures.