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Low-fat dairy products don't have desirable texture and sensory properties because of having low levels of fat. Pear powder can be used as a carbohydrate-based fat replacer for fortification and improving the texture of low-fat dairy products due to having a positive effect on texture improvement and desirable nutritional compounds such as pectin, lignans, phenolic compounds and dietary fiber. In this context, pear powder was added to milk (1.5% fat) at levels 1, 2 and 3%. The experimental yogurts were compared with control yogurts produced from whole milk (3% of fat) and low-fat milk (1.5% of fat). The samples were stored for 15 days at 4 ± 1 °C and their physicochemical, texture and sensory properties were evaluated during storage. According to results, increasing the rate of pear powder in yogurt samples caused to a significant increase in acidity, viscosity, water- holding capacity and firmness and decrease in pH and syneresis (p<0.05). In all samples, while acidity, viscosity, firmness and water-holding capacity increased significantly during storage, pH and syneresis decreased (p<0.05). The sample containing 3% pear powder and low fat control sample had highest (0.215 N) and lowest (0/09 N) firmness, respectively. Sensory evaluation performed by the panelists also showed that the overall acceptability was higher at full fat control yogurt (19.70 score) and samples treated with 1% (19.64 score) of pear powder than other samples. According to the results, it was found that the pear powder at 1% level could improve the sensory and qualitative properties of yogurt samples. [ABSTRACT FROM AUTHOR]

Yogurt as a member of fermented food family has been considered an appropriate food system in order to transfer nutraceutical and plant extracts in daily consumption. Thereupon omega-3 fatty acids of plants oil including Purslane and flax seeds oil could be suitable targets to produce functional yogurts. In this study, the effect of replacement purslane oil (0.5 %, 1.5 %, 2 %) and Flaxseed Oil (0.5 %, 1.5 %, 2 %) to yoghurt on some physicochemical and sensory properties were investigated. The enriched yogurt was examined for after production days at 4°C. The evaluation of fatty acid profiles showed that the replacement of Purslane Oil and Flaxseed Oil in treatments reduced the amount of saturated fatty acids and increased the amount of unsaturated fatty acids. The results physicochemical showed that the effect of Purslane and flaxseeds oil in during storage pH decreased; however, the acidity, dry matter and synergies of all samples increased significant (p≤0.05). While crude fat content of treatments didn’t alter significantly (p>0.05). While crude fat and dry matter content of treatments didn’t alter significantly. On the other hand, oxidative sensibility of treatments showed a reverse correlation with Purslane and flax seeds oil substitution, so that all the samples had a far higher peroxide values than control sample (p≤0.05). The evaluation of sensory properties yogurt treatments showed Purslane and flaxseeds (except in 1.5 and 2 percent substitution) had the sensory properties no significant effect. The evaluation showed that treatment containing 0.5% Purslane Oil was introduced as the best treatment and had the highest level of acceptance was for consumers. [ABSTRACT FROM AUTHOR]

In this research, the effect of whey protein concentrate (WPC) in the concentrations of 13, 16 and 19 percent with some of stabilizers including carboxymethyl cellulose (CMC), pectin and chitosan on the physicochemical properties such as acidity, pH, viscosity, overrun and melting resistance, as well as sensory properties such as taste, texture and overall acceptability in frozen yogurt were investigated. The results of statistical analysis showed that the effect of experimental treatments was significant (P<0.01) on all characteristics evaluated. By increasing the concentrations of WPC, increased the acidity and viscosity of the samples containing all three types of stabilizers, but decreased the pH, overrun and melting resistance percentage of frozen yogurt samples. The samples of frozen yogurt that enriched with carboxymethyl cellulose showed higher viscosity value than samples containing pectin and chitosan, but maximum percentage of overrun and melting resistance was observed in samples containing pectin. In evaluating the sensory characteristics, frozen yogurt containing 13% WPC and pectin had the highest score. According to the results of the physicochemical and sensory properties of frozen yogurt samples, the combination of whey protein concentrate with a concentration of 13% and pectin stabilizer was selected as the superior treatment. [ABSTRACT FROM AUTHOR]