Development of a stable fermented creamy structure from hazelnut in the scope of plant-based food production

A hazelnut-based fermented creamy structure was developed from whole hazelnut kernels in the scope of plant-based food production. Firstly, heat-induced and acid-induced gelation of aqueous slurries of raw or roasted hazelnut kernels were investigated. The final structure was formed by heat treatment and fermentation by yoghurt culture along with supplementary sucrose. A stabilizer mixture of locust bean gum and xanthan gum was needed to prevent phase separation. Roasting treatment of hazelnuts reduced the temperature and increased the pH at which gelation started; however, a weak gel was obtained. On the other hand, fermentation of raw hazelnuts resulted in a gel structure with higher strength, yield stress, flow point and spreadability. Phase separation was not observed in the structures during storage. Viable lactic acid bacteria count was above 6 log cfu/g in the samples and a slight decrease was observed after storage at 4°C. Soluble protein content in the samples was reduced by roasting and fermentation but increased after storage. Roasting enhanced allergenicity of the water-soluble fraction while fermentation decreased it by about 70%. Raw hazelnuts are recommended for preparation of stable fermented gel structures with reduced allergenicity towards plant-based food production.