The effect of hazelnut roasting temperature and time conditions on technological properties of cocoa hazelnut spread

In this thesis, cocoa hazelnut cream was produced from hazelnuts roasted at different temperature and time conditions. The effect of roasting temperature and time on physicochemical, textural, rheological and sensory properties of cocoa hazelnut creams were investigated. For this purpose, HYA, water activity, colour analysis, textural spreadability analysis, rheological analysis, particle size distribution analysis and sensory analysis were carried out. No difference was found between the water activity, firmness, viscosity particle size distribution parameters d(0,1), d(0,5), d(0,9), D[3,2], D[4,3] values, shear stress and apparent viscosity values, K coefficient of consistency, linear (τ1) yield stress and characteristic shear rate, colour L*, a*, b* values, sensory colour, appearance, consistency and spreadability scores of cocoa hazelnut creams. However, sample type was found to be significantly effective on general odour, hazelnut odour, flavour and hazelnut aroma (p<0.05). As a result, no statistically significant difference was observed in the physicochemical, textural and rheological tests of the different degrees of heat treatment applied in this study on cocoa hazelnut cream. However, it was determined that cocoa hazelnut cream produced by roasting at 175 ºC for 25 minutes was superior in terms of general odour, hazelnut odour, general flavour and hazelnut aroma in sensory tests.