# Production of Vegan Ice Cream: Enrichment with Fermented Hazelnut Cake
## 3 Results and Discussions
### Textural Properties of Ice Cream Products  
The texture of ice cream is one of the most important quality attributes that affect consumer preference [51]. Texture is considered the sensory reflection of the structure; therefore, the creation and maintenance of the optimum ice cream structure is critical for maximum textural quality. The colloidal structure of ice cream starts with a simple emulsion mixture with a separate phase consisting of partially crystallized fat globules surrounded by an interfacial layer of proteins and surfactants [47]. The structural properties of DIC, HIC, and FHIC were examined by texture analysis (Figure 2). Hardness is the resistance of ice cream to deformation when an external force is applied [25]. The hardness levels of HIC and FHIC are quite close to each other and significantly higher than DIC (\(p<0.05\)). [PERSON] et al. (2022) attributed the differences in hardness between ice creams obtained from almond milk and hemp milk to different types and amounts of fat and protein in the products [52]. They reported that this situation affected the formation of ice cream crystals, thus increasing the hardness and consistency of ice cream. The hardness values of soy ice cream and sesame ice cream samples were reported as 1442 g and 1820 g, respectively [53]. Like our study, the hardness value of traditional ice cream (836 g) was significantly lower (\(p<0.05\)). These values are in accordance with the hardness values of our DIC, HIC, and FHIC. Hardness can be considered as a reflection of the mixture of components (fat, protein, sugars, and hydrocolloids) and the process conditions (homogenization, ripening, and freezing) of the final product. The hardness of ice cream is influenced by various elements, including the types and quantities of protein and fat, the production and dispersion of ice crystals, fat instability, and the volume of the ice phase [54]. In vegan ice cream, the hazelnut proteins might form a more rigid network than dairy proteins. In addition, coconut oil might lead to a firmer texture at serving temperatures due to a higher melting point than milk fat. Vegan ice creams may have larger or more ice crystals due to differences in freezing behavior. It should also be noted that HIC and FHIC had a lower overrun, which could contribute to a denser and harder texture. Fermentation may also affect the hardness since it breaks down the proteins into smaller peptides, which might reduce elasticity and increase brittleness. Adhesiveness is the force required to separate food from the surface of other materials [55]. In the case of ice cream, the adhesiveness value represents the additional energy required to overcome the attractive forces between the ice cream and the mouth [45]. The adhesiveness values of DIC ranged from 0.86 to 2.75 mJ, which is significantly higher than HIC and FHIC. [PERSON] et al. (2021) produced soy (4.2 mJ), sesame (8.7 mJ), and traditional dairy (6.9 mJ) ice creams that had considerably higher adhesiveness values compared to our study [53]. [PERSON] et al. (2020) stated that adhesiveness values may increase when the protein-protein network structure develops in ice creams [55]. [PERSON] et al. (2021) stated that adhesiveness values increased in ice cream samples to which whey powder was added and that this was due to the increase in the total solid content [56]. In addition, [PERSON] al. (2009) attributed this increase to the powder added to the ice cream interacting with water, other proteins, and flavor components and affecting the texture [57]. Their findings indicated that the rise in viscosity enhances the adhesiveness of ice cream, aligning with our conclusions about its flow behavior. DIC and HIC exhibit markedly greater viscosity compared to FHIC, correlating with elevated adhesiveness values relative to FHIC. Due to protein breakdown from fermentation and weakening of the matrix, FHIC had the lowest adhesiveness.