Development Of Symbiotic Oat Based Frozen Yogurt And Its Cholesterol Reducing Effects In Rats

Ice cream is one of the most popular dairy food in the world. But it has long beenrecognized as a high energy food and may be not suitable for certain segments of thepopulation. With the improvement of the living standards, much more attentions werepaid to the functional products. Therefore, the development of functional ice creamproducts has become a major trend in the food industry.Oats contain a wide range of nutrition ingredients and oats based products areconsidered as functional foods due to the cholesterol-lowering component, β-glucan.Owing to oat based products are limited in the market, it is necessary to oat frozenyogurt for consumers. Interaction between probiotics and prebiotics have been studiedfor years by experts and scholars. Under the condition of their coexist, the activity ofprobiotics can be enhanced. Soy protein isolate is a plant protein with high quality.Other vegetable oils added also have prominent functionality. The objectives of thisstudy were to develop a symbiotic oat based frozen yogurt containing fermented oat,probiotics (Bifidobacterium and Lactobacillus acidophilus) and inulin (prebiotic) andto evaluate the effects of oat based frozen yogurt on serum triglycerides andcholesterol in rats.Percentages of5%、10%、15%、20%、25%oat flour,20%、30%、40%、50%oat based material and1%、2%、3%、4%、5%soy protein isolate were added into thebase. The overrun, melt rate, viscosity, hardness, pH and sensory evaluation of thesymbiotic oat based frozen yogurt were analyzed. The results showed that thesymbiotic oat based frozen yogurt was found to have good functionality by additionlevel of20%oat flour,50%oat based material and3%soy protein isolate.Chemical composition of the oat based frozen yogurt were analyzed. The resultsshowed protein content were (4.10±0.09)%, fat content were (8.50%±0.15)%, thecontent of total solid were (34.30±0.19)%, dietary fiber content were (2.10±0.02)%,Na content were(2.28±1.30)mg/100g, Ca content were (275.31±23.81)mg/100g and Zn content were (0.64±0.03)mg/100g. All these results satisfied the requirements ofnational standards of the ice cream. During the storage of8weeks, the survivability ofthe probiotics in the symbiotic oat frozen yogurt was evaluated. The initialpopulations of Bifidobacterium and Lactobacillus acidophilus in the experimentalfrozen yogurt were8.40×106CFU/ml and5.60×103CFU/ml, respectively.Bifidobacterium survived much better during8weeks of storage at-18℃comparedwith L. acidophilus. pH declined from5.0to4.3during8w. The titratable acidity ofoat frozen yogurt increased from26.1T°to33.8T°. After all health indicators wereanalyzed, the results showed symbiotic oat frozen yogurt satisfied the requirements ofnational standards.The rats (Wistar) were conditioned and the levels of TG and cholesterol weremeasured before and after feeding trials. Rats (3groups) were fed with dietscontaining25%(L),30%(M),35%(H) of the oat frozen yogurt, respectively,compared with the rats fed with a diet containing30%commercial ice cream (C), anda control group fed with a standard diet (N). The TG levels in the rats of both groupsfed with diet M(p<0.05) and H(p<0.01) were significantly lower than that of group C.There was a very significant difference in total cholesterol (TC) and LDL cholesterolbetween rats fed with H diet group (i.e.,35%) and the rats fed with diet containingcommercial ice cream (p<0.01). There was no significant difference in TG betweenrats fed with standard diet (p>0.05), but the differences in TC, and LDL were verysignificant between the groups (p<0.01). Results indicate that consumption of oatbased frozen yogurt may decrease the levels of serum TG, total and LDL cholesterolin rats.