Effect of drying method on mechanical, thermal and water absorption properties of enzymatically crosslinked gelatin hydrogels

Abstract

Enzymatically crossliked gelatin hydrogel was submitted to two different drying methods: air drying and freeze drying. The resulting polymeric tridimensional arrangement (compact or porous, respectively) led to different thermal and swelling properties. Significant differences (p < 0.05) on thermal and mechanical characteristics as well as swelling in non-enzymatic gastric and intestinal simulated fluids (37 ºC) were detected. Water absorption data in such media was modelled according to Higuchi, Korsmeyer-Peppas, and Peppas-Sahlin equations. Freeze dried hydrogel showed Fickian diffusion behavior while air dried hydrogels presented poor adjustment to Higuchi model suggesting the importance of the relaxation mechanism at the beginning of swelling process. It was possible to conclude that the same gelatin hydrogel may be suitable to different applications depending on the drying process used.

Influence of Chain Structures of Starch on Water Absorption and Copper Binding of Starch‐Graft‐Itaconic Acid Hydrogels

“…The hydrogels presented a smooth surface with no visible pores, and the cross‐sections also revealed a compact and continuous structure. It has been shown that the drying method used in this study can have a considerable impact on the morphology of hydrogels . Air drying causes water to evaporate slowly, allowing time for the polymer chains to adopt a stable equilibrium conformation.…”

“…Air drying causes water to evaporate slowly, allowing time for the polymer chains to adopt a stable equilibrium conformation. This produceed polymer networks with smooth, compact surfaces …”

Tensile Fatigue of Poly(Vinyl Alcohol) Hydrogels with Bio‐Friendly Toughening Agents

“…[ 78 ] Air‐drying and freeze‐drying of hydrogels can often lead to changes in the swelling, mechanical, or thermal behavior. [ 80,81 ] In addition, crystallinity of a swollen gel is not always proportional to that of a dried gel. [ 82 ] As a result, any change in the crystallinity degree could not be appropriately assigned to the presence of starch, as it would be unclear what role a particular drying process may have played.…”

Tailoring swelling of alginate-gelatin hydrogel microspheres by crosslinking with calcium chloride combined with transglutaminase

“…dry-basis) (Y 1 , %wt), and swelling degree (SD) at pH 3 (Y 2 , %wt) and pH 7 (Y 3 , %wt). The experimental factors were chosen based on preliminary results reported by the research group (Simoni et al, 2017), while pH 3 and 7 were chosen due to the suitability for food applications, since a large number of products present pH values in the range 3-7. Examples included condensed milk (pH 6.59), fresh milk (UHT-processed) (pH 6.09), mayonnaise (pH 3.46), pineapple jam (pH 3.02) (Gabriel, 2008).…”