## 3 Results and Discussion
### Texture Profile Analysis of Set Yoghurt  
As one of the most pronounced factors, texture influences the quality and acceptance of yoghurt significantly [27]. Several parameters including hardness, cohesiveness, gumminess, chewiness, springiness, and adhesiveness play vital roles in the textural assessment of yoghurt [28]. Hardness is the most commonly assessed characteristic in determining the texture of set yoghurt and could reflect its gel state directly. Previous study reported that greater hardness implied better coagulation [29]. According to Figure 2a, the hardness of set yoghurt with 0.05%, 0.10%, and 0.15% RE was significantly higher than that of the control after 24 h of low-temperature storage, indicating that the addition of RE enhanced the gel-forming properties of set yoghurt. Additionally, the hardness exhibited increasing trend with RE concentration, although no significant difference was observed between the 0.05% and 0.10% RE samples (Figure 2a). Similar findings were reported during the functional exploration of _Pleurotus ostreatus_ (oyster) mushroom polysaccharides in yoghurt fermentation and storage [30]. There is a relationship between the microstructure of set yoghurt and hardness; a compact structure could cause more hardness and lower water drainage [31]. Consequently, RE could stabilize set yoghurt and improve the WHC (Figure 1b). Figure 1: pH and WHC of set yoghurt after low-temperature storage of 24 h. (**a**) pH; (**b**) WHC. Different lowercase letters indicated significant differences (_p_ < 0.05) among different yoghurts using one-way ANOVA analysis with a Tukey test. Cohesiveness is commonly defined as the degree of force required to pull the probe from the sample and depends on the strength of the internal bonds in the set yoghurt [32]. The smaller the cohesiveness of the set yoghurt, the better the smoothness [29]. As shown in Figure 2b, the cohesiveness of set yoghurt between the 0.05% RE and control samples  
Figure 2: Texture profile analysis of set yoghurt after low-temperature storage of 24 h. (**a**) Hardness; (**b**) cohesiveness; (**c**) gumminess; (**d**) chewiness; (**e**) springiness; (**f**) adhesiveness. Different lowercase letters indicated significant differences (\(p<0.05\)) among different yoghurts using one-way ANOVA analysis with a Tukey test. was not significantly changed after 24 h of low-temperature storage, as well as that between the 0.10% and 0.15% RE samples. However, the cohesiveness of set yoghurt with the 0.10% and 0.15% RE samples was significantly lower than that of the control sample (Figure 2b). These results suggested that the addition of RE could improve the smooth texture of set yoghurt significantly. Similar results were also reported in the studies on the effects of polysaccharides isolated from _Pleurotus ostreatus_ (oyster) mushroom and _Auricularia cornea_ var. Li on the yoghurt after 24 h of low-temperature storage [30; 33]. Gumminess is related to the hardness of set yoghurt [34]. Therefore, this parameter is generally defined as the energy needed to fragment a semisolid food until it is ready to swallow [28]. As can be seen in Figure 2c, the gumminess of set yoghurt showed an increasing trend with RE concentration, although no significant difference was found between the 0.05% and 0.10% RE samples. This trend was consistent with hardness (Figure 2a). The outcome is similar to a previous study where inulin could increase the gumminess of yoghurt with the increasing concentration of the polysaccharide after 24 h of low-temperature storage [28], while it is contrary to that of \(\beta\)-glucan investigations [35]. In addition, chewiness is the time or work required to masticate a sample to reduce it to a state ready for consuming [28]. The parameter showed a similar increasing trend to gumminess as the RE concentration increased (Figure 2c,d). Proper gumminess and good chewiness are beneficial for improving the human eating experience and increasing consumer satisfaction and re-consumption willingness [36].