Effects Of Alditols On Gellan Gel And Application Of Gellan Gum

Gellan gum is an effective gelling agent, having a wide application in food industry forits advantages of low dosage, transparent gel, adjusted gelling temperature and other moreexcellent properties. The effects of cations, pH, temperature and sugars on gellan gel had beenstudied intensively, which made a big contribution to industrial application of gellan gum.Alditols are functional sweetners, playing an important role in suger-free food industry.However, there was neither report about effects of alditols on gellan gel properties nor ongellan gelation up to now. In order to explore application feasibility of gellan gum insugar-free food, the effects of alditols on the performance of gellan gel properties and gellingtemperature were studied in detail in this text. Besides, corresponding to the above theoreticalstudy, preliminary application of gellan gum in suger-free multi-layer jelly was also included.The effects of alditols on mechanical properties and clarity of gellan gel wereinvestigated by the way of compression mode of texture analyzer and gel absorbance. Theeffects of alditols on gellan gel were closely related to concentrations of gellan gum or alditols,molecular weights of alditols and cation conditions. With alditol additions the gel strength andhardness decreased, while brittleness remained. At the same time, clarity of gellan gelsincreased when adding80mmol·L-1K+. The impact of the three alditols was found in theorder: lactitol> xylitol> erythritol. The effects of alditols on the gellan gel becameremarkable with increasing concentration of alditols or gellan gum. The effects of mixedalditols on the gel properties of gellan were less than that of individual alditol at the sameconcentration, i.e., no synergistic interaction between the individual alditols was detected.Alditol additions affected remarkably on gel properties in any concentration of K+. However,alditols affected gel properties only in low concentration of Ca2+(2~5mmol·L-1), while hadlittle impact on gel properties in higher concentration of Ca2+(≥10mmol·L-1).The effects of alditols on gellan gelling temperature were measured by time-temperaturescanning of dynamic rheology. It was showed that the effects on gellan gelling temperaturerelated to cation conditions. When adding80mmol·L-1K+, gellan gelling temperature was38.4°C. Under the same condition, with erythritol and xylitol additons gelling temperatureincreased, while with lactitol additions gelling temperature decreased. When adding10mmol·L-1Ca2+, gellan gelling temperature was39.2°C. However, alditols had little influenceon gelling temperature. Ca2+was the dominate factor during gelling, so effects of alditols ongelling temperature could almost be ignored.Basing on the theoretical study on the effects of alditols on gellan gum, application ofgellan gum in multi-layer jelly was explored tentatively. In the study of gellan gumapplication, Ca2+was used as gelling cation, mixed alditols of erythritol, xylitol and lactitolwith mass ratio1:1:1as sweetners, and blends of gellan gum and XG73(XG73were themixtures of xanthan gum and konjac glucomannan with the mass ratio7:3) as gelling agent.The optimal fundamental formula investigated by single-factor and orthogonal experiments:Ca2+was7.5mmol·L-1, concentration of blended hydrophilic colloids was0.5%(w/v), massration of gellan gum in blended hydrophilic colloids was30%, concentration of mixed alditols was15%(w/v). The optimal fundamental formula was determined feasible with similartexture with the saling jelly—Xizhilang, and an even better water capacity. A type ofthree-layer jelly was made by adding some supplementary food agents in the optimalfundamental formula with milk in upper and under layers and juice containing citric acid inmiddle lay. The sensory storage life was60days in room temperature, which was determinedby the variation of concentration of citric acid in the the three layers and appearance duringstorage in the room temperature.