M.Sc Thesis

M.Sc StudentBashan-Hadas Ravit
SubjectEffect of Dietary Fibers and Sugar Substitutes on
Texture, Nutritional and Organoleptic Properties
of Chocolate
DepartmentDepartment of Biotechnology and Food Engineering
Supervisors PROFESSOR EMERITUS Chaim Mannheim (Deceased)
Full Thesis text - in Hebrew Full thesis text - Hebrew Version


Chocolate is a widely spread and favored product, thanks to its unique taste and texture. Cocoa beans contain flavonoids known to be antioxidants as well as stimulating substances such as caffeine and theobromine. The disadvantage of milk chocolate is its high energy, approximately 550 kcal/100g. Sucrose, which comprises half the weight of the chocolate, contributes significantly to its caloric value and Glycemic Index (GI), rendering regular chocolate unsuitable for diabetics. In the current study the sucrose of milk chocolate was replaced with dietary fibers and sugar substitutes, in order to improve its dietary properties, by reducing the caloric value by 30-33%, i.e. to 370-390 kcal/100 g. Furthermore, a second major goal was to lower the GI below 50, while preserving the physical and organoleptic properties of regular milk chocolate. In the selected composition, sucrose was replaced by the sugar alcohols maltitol and erythritol, by sucralose and by the dietary fibers inulin and NutrioseÒ. These components, together with cocoa mass, cocoa butter and milk powder, constituted the reduced-calorie milk chocolate. The results show that the viscosity, at 40°C, of the liquid reduced calorie product, enabled production on a commercial line. Differential Scanning Calorimetry tests showed that the cocoa butter melted at a similar rate and over a similar temperature range in the reduced calorie and regular milk chocolate. However, the observed enthalpy change, ΔH, showed that a higher energy was required to melt the cocoa butter in the reduced calorie chocolate. Texture analysis, using the penetration of a needle into the chocolate, showed that replacing the sucrose by the five ingredients, yielded a texture similar to that of the regular chocolate. In cryo Scanning Electron Microscopy imaging, no differences were observed between surface features of the two types of chocolate, although X-Ray Diffraction analysis showed that they possessed different structures. In extensive sensory evaluation tests, no significant differences were found between the reduced calorie product compared with the regular one.  The reduced calorie chocolate had a caloric value which was 70% that of regular milk chocolate, and a reduced GI of 20±4. This low GI gives the reduced-calorie milk chocolate a significant nutritional advantage over that of regular chocolate (GI of 50±5). The results show that this novel type of chocolate provides an advantage to diabetics and also enables chocolate lovers to cope with the problem of weight gain.