Role of process variables on the formation and in vitro digestion of gellan gels.

Gellan gels were produced using different approaches forming structures with varied potential applications. Gels were characterized from appearance, mechanical properties, water holding capacity (WHC) and microstructure. In addition, in vitro digestibility of these gels was evaluated to understand the effect of gastrointestinal environment on their structure stability. All gels presented high WHC (>80% w/w) but gels were stronger with salt or acid addition, which was associated to the reduction of double helices repulsion of the negatively charged carboxyl groups of gellan. Moreover, low gelation rate induced a more controlled gellan helices aggregation, strengthening even more gels structure. Gellan gels presented resistance to digestion conditions but hardness of these gels during digestion mainly depended on the gelation rate. Based on these findings it would be possible to tune gel properties for a specific application as texture modifier or even as a faecal bulk formation assistant and an "ileal break" inducer.