Research On Traditional Hurood Fermentation Agent And Its Application

Cheese Hurood as the Mongolian’s traditional food,also represents the food culture.However,traditional cheese Hurood mostly made by naturally fermented,with significantly differences in properties and a slightly harder texture.Research has shown that lactic acid bacteria as fermentation agents can improve the quality characteristics of cheese,and the exopolysaccharides produced by lactic acid bacteria can also improve the taste,structure,and stability of cheese during storage.Therefore,in order to improve the texture of Mongolian cheese Hurood and improve its quality during storage,two lactic acid bacteria which can produce exopolysaccharides were selected as the fermentation agent to produce Mongolian cheese Hurood in this experiment.The main results are as follows:(1)Early in the laboratory,13 identified lactic acid bacteria strains of which relatively strong acid production,milk clotting,and whey excretion abilities were screenned,the EPS producing strains in liquid MRS medium,and the viscosity of the fermented milk was consided.Finally,two high exopolysaccharide producing strains was selected: Lactobacillus plantarum 686 and Lactobacillus lactis NDF 2-4;among which,the EPS production of Lactococcus lactis NDF 2-4 is 440.01 mg/L,the viscosity of fermented milk(50rpm)is 770.23 Pa·s,the EPS production of Lactobacillus plantarum686 is 309.38 mg/L,and the viscosity of fermented milk(50rpm)is 608.35 Pa·s.(2)Lactobacillus plantarum 686 and Lactobacillus lactis NDF 2-4 were used as fermentation agent to prepare cheese Hurood.Single factor and orthogonal optimization and validation experiments were conducted on the bacterial ratio,inoculation amount,fermentation temperature,and whey discharge temperature to improve the sensory score and texture parameters of cheese Hurood.The optimal parameters were: "Lactobacillus plantarum 686" and "Lactobacillus lactis NDF 2-4" 1:2,with an addition of 3%,fermentation temperature of 27 ℃,and whey discharge temperature of 65 ℃.The sensory score of the prepared cheese Hurood is 86.38,corresponding to a hardness of2108.78 ± 0.10 g and an elasticity of 0.95 ± 0.03 g.(3)The texture and sensory properties of the cheese Hurood prepared under the optimal process conditions in this experiment was compared with the commercially available simples and with commercial fermentation agents prepared simples during the storage period of 0,4,8,12,16,and 20 days.The results showed that,the Hurood fermented by exopolysaccharide producing lactic acid bacteria had relatively smaller hardness,chewiness,and adhesiveness,and relatively larger elasticity,cohesion,and resilience,indicating that the exopolysaccharide produced by lactic acid bacteria could further reduce the hardness of Hurood,and improve the resilience and cohesion,and have a relatively better texture improvement effect.During storage,exopolysaccharides improved the water retention,reduced the rate of change in hardness,elasticity,chewiness,and other aspects of cheese Hurood,and also ensure that the texture of cheese Hurood remains relatively stable for a long time.Compared with commercially available cheese Hurood and commercial agents fermented cheese Hurood,the sensory quality of cheese Hurood in the experiment is also improved.