The effect of plant mucilaginous gel polysaccharides on oxidative tolerance and fermentation of dietetic yoghurts

This study aimed to investigate the effects of plant gel polysaccharides extracted from Aloe vera leaf on the fermentation and biotherapeutic properties of functional yoghurts. In this study, Aloe vera gel was used as a potential prebiotic, dietary fiber and stabilizing agent, stevia as a natural sweetener, and mixed probiotic starter (Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus, Bifidobacterium animalis ssp. lactis, Lactobacillus acidophilus) were used as a culture. To evaluate the bio-functional activity of yoghurt, analyses of probiotic bacterial growth, the total phenolic compounds and copper-reducing antioxidant capacity were carried out. While the stabilisation of yoghurt gel was determined by the textural properties, consumer preference was evaluated by sensory hedonic scales. When the phytochemical effect was evaluated, polysaccharides and phenolic compound present in Aloe vera gel supported bacterial growth. In addition, the polysaccharide gel caused the formation of a more firm coagulum in the produced yoghurts. The addition of stevia into yoghurt accelerated fermentation most probably by the potential stimulating effect of steviol glycosides on bacterial growth. The obtained results indicate that Aloe vera gel and stevia have a synergistic effect with bioactive polysaccharides, in the production of healthy foods for special nutritional purposes by improving the properties of the product and modulating the intestinal microbiota.