Gelification or jellification is the act of turning food into jelly; or to become become gelatinous. Such food additives convert liquid substances into solids. Modern gelling agents come from natural sources and include agar-agar, gelatin, carageenans (including kappa, lambda iota), gellan gum, pectin and methylcellulose. These ingredients usually take the form of dry powders which require the addition of liquid to trigger the jellification reaction.
The process of jellification of various foods has gone on for centuries using such common ingredients as flours, tapioca or corn starch, eggs and actual animal gelatin. But, in recent years non-traditional ingredients such as hydrocolloids have been refined for both processed foods as well as in modern gastronomy as the process serves to stabilize liquids without affecting taste.
In modern gastronomy jellification adds texture and creates unique presentations in various dishes. Depending on the nature and concentrations of the gelling agent being used, the gel texture can range from supple and elastic to firm and brittle. This enables inventive cooks to experiment and attain the exact desired texture!
The use of hydrocolloids allows a cook a much greater control of recipes. A variety of gels can thus be formed with a wider range of textures at temperatures, pH levels and with foods that are impossible to gel with common gelling agents. In addition, the concentration needed to achieve the desired result is often lower, which is a significant advantage that avoids excessive changes in flavor. Another advantage of of hydrocolloids in cooking is that they provide a vegetarian gelatin alternative to animal gelatin.
In addition to the control advantage that hydrocolloid gels provide is the degree of transparency that can be achieved. As an example, sodium alginate, gelatin and iota carrageenan produce completely clear gels. Agar-agar produces gels that are somewhat opaque. Whereas, kappa carrageenan and gellan gum will produce gels whose transparency ranges from slightly opaque to completely opaque.