PRODUCTION OF REDUCED-CALORIE GRAPE JUICE JELLY WITH GELLAN, XANTHAN AND LOCUST BEAN GUMS - SENSORY AND OBJECTIVE ANALYSIS OF TEXTURE

The production of reduced-calorie grape juice jellies with gellan, xan than and locust bean gums (LBG) was studied. Twenty formulations of gr ape juice jelly were prepared according to a second-order composite ro tatable design (with six central points). Response surface methodology (RSM) was used to optimise jelly formulation using as independent var iables: total sugar content, ranging from 14 to 46 degrees Brix; and t otal gum concentration ranging from 0.30 to 0.70% (w/v), with the prop ortion of gums in the mixture xanthan:LBG:gellan ranging from 5:5:90 u p to 45:45:10. The processing temperature used was 90 degrees C for co mplete solubilisation of gums. The dependent variables were objective measures of texture and a parameter obtained from sensory analysis, th e overall balance (B), which represents the overall evaluation of the jelly. The resulting polynomial equation (R-2=0.929) revealed that a j elly produced with white grape juice, total sugar with sucrose equal t o 39.3 degrees Brix, and, 0.54% (w/v) of total gum added in the propor tions of: 1:1:1.7 (gellan:xanthan:LBG) had a maximum value of B. The s ensory-optimised jelly was objectively characterised for texture and t he model was tested. The texture characteristics, i.e. gel hardness, c ohesiveness and springiness, were found to be similar to those of a re ference product, a previously developed reduced-calorie grape juice je lly with low methoxyl pectin.