EFFECT OF DIFFERENT CONCENTRATIONS OF OIL WITH LOW MELTING POINT ALONG WITH ALGINATE ON THERMAL STABILITY OF LACTOBACILLUS RAMONOSUS BY FREEZING DRYING METHOD IN DOOGH

Background and Aim: Effect of different concentrations of oil with low melting point along with alginate on thermal stability of Lactobacillus Ramonosus by freezing drying method in DooghMethods: In recent years, there is a growing tendency to use probiotic microorganisms as good health factors in dairy products. One of these products is probiotic dough. The creation of beneficial health benefits depends on their survival as long as they are consumed within the standard range (cfu / g107-106). So these bacteria have reached high levels in the intestines and have their own beneficial effects. Thermal resistance of these bacteria is limited by the use of these bacteria in products that are present during the thermal process such as pasteurization. One of the methods for increasing the thermal resistance of bacteria is the encapsulation using protective compounds. In this research, the thermal resistance of three different bacterial Lactobacillus rhamnosus strains was measured from isolated pills and native mothers. The results showed that the highest thermal resistance was related to the indigenous Rhmnusus bacterium. Then the thermal resistance of indigenous Ramonosus bacterium was investigated for 5 minutes at temperatures of 50, 60, 65, 70 and 80 degrees Celsius. In the next step, the microencapsulation of Lactobacillus rhamnosus with alginate and low melting point oil (LMF) was performed. LMF was added to different ratios (10%) to alginate solution (1% w / w, 40 ℃), 10% sodium caseinate, 10% skim milk. The above-mentioned solutions were used as a control group without dextrose. After drying, the bacterial survival rate was evaluated after encapsulation and after heating with kettle in a dough solution at 70 ° C for 30 seconds, 1 minute and 5 minutes.Conclusion: The results of the thermal resistance of free bacteria indicate that the highest drop in viability is at all temperatures after 30 seconds due to the initial thermal shock of the bacterium. Survival and survival of bacteria at 50, 60 were reduced by about 50% and did not differ significantly. At 80 ° C, only 25% of the loss of life was created. Which shows that the native Lactobacillus rhominosus bacteria has a relatively good thermal resistance. The results showed that the encapsulation alone and even with 1% LMF concentration had no significant effect on the thermal resistance of the bacterium, but by increasing the concentration of LMF to 5% and 10%, respectively (9% and 20%, respectively) P> 0.05), it is heated in the viability of the bacteria for 5 minutes. In fact, the results show that LMF has been able to absorb some of the thermal process. According to the results, low melting point oil (LMF) could be used to increase the thermal resistance of lactobacilli.

کلیدواژه ها:

Alginate ، sodium casheinate ، skim milk ، indigenous Lactobacillus rhamnosus ، LMF (oil with low melting point) ، microcapsulation ، bacterial thermal resistance ، freeze drying