Use of DSC To Detect the Heterogeneity of Hydrothermal Stability in the Polyphenol-Treated Collagen Matrix

Abstract

The hydrothermal stability of the collagen matrixes treated with plant polyphenols (tannins) depends on not only the strength of the polyphenol-collagen interactions but also the distribution uniformity of polyphenolic molecules within the collagen fibrils. Traditional methods of uniformity tests rely heavily on the expertise of workers and are thus subjective. This paper describes a differential scanning calorimetry (DSC) study of the sheepskin collagen samples treated with hydrolyzable tannins, including two commercial tannins' extracts (chestnut and valonea), two pure ellagitannins (vescalagin and castalagin), and six synthetic gallotannins (di-galloyl-ethylene glycol (DGE), tri-galloyl-glycerol, tetra-galloyl-meso-erythritol, penta-galloyl-adonitol, penta-galloyl-glucose, and hexa-galloyl-ducitol). The collagen sample without polyphenol treatment and the sample treated with DGE showed a single sharp peak in their DSC thermogram with a full peak width at half height (fwhh) of 3-4 degrees C. The samples treated with other tannins all showed multiple peak DSC profiles with the fwhh of each peak at about 3-4 degrees C. These multiple peak profiles imply that in these polyphenol-treated samples, there is a distribution of collagen molecules having different hydrothermal stability. The results have demonstrated that DSC offers an objective method to detect the stability heterogeneity of collagen matrixes in the solid state, providing a useful tool for the leather industry to evaluate the uniformity of leather tanning.

Stabilization of collagen using plant polyphenol: Role of catechin

“…Tannins are known to readily bind with collagen [24,25]. It is of interest to know how the precursors of tannin bind with collagen.…”

Modification of collagen with a natural cross-linker, procyanidin

“…And the benefit of antioxidant activity, pharmacological activity and therapeutic potential from procyanidin has been extensively manifested [15,16]. In fact, natural plant polyphenols including procyanidin have long been used to treat animal hide collagen under acidic conditions and confer enhanced stability against heat and putrefaction to the resultant leather [17][18][19]. In practical leather-making, the required amounts of the vegetable materials can be 10-40% (w/w) depend on its affinity for hide substance [20].…”

Unravelling the mechanism of the interactions of oxazolidine A and E with collagens in ovine skin

“…presence of collagen molecules with differing thermal stability. Wide peaks such as these will be resolved into multiple peaks only when the differences between the thermal stabilities of the collagen fractions reach a certain level [14]. Although the wide peaks did not resolve into multiple peaks in this study, the presence of more than one population of collagen molecules was clearly present.…”