Milk sourced psychrophile and extracellular enzyme secreted by same

Abstract

The invention discloses a milk sourced psychrophile and an extracellular enzyme secreted by the same, belongs to the field of milk product processing and aims to provide a milk sourced psychrophile with poorer heat resistance and the heat-resistant extracellular enzyme secreted by the milk sourced psychrophile. The milk sourced psychrophile is classified and named as a pseudomonas fluorescens W3 strain with the conservation number being CGMCC No.14540 and is conserved in CGMCC (China General Microbiological Culture Collection Center) on August 21, 2017. The extracellular protease produced by the strain has the activity about 7.0-8.2 U / mL, the produced extracellular lipase has the activity about 6.8-7.5 U / mL, and the extracellular protease and lipase produced by the strain have certain heatresistance and have important characteristics of advantageous psychrophile in raw milk; and the strain comes from the raw milk and can be used for study of damage of the psychrophile to milk and a milk product and control methods.

Description

technical field [0001] The invention belongs to the field of dairy processing, and in particular relates to a milk-derived psychrophilic bacterium and an extracellular enzyme secreted therefrom. Background technique [0002] With the development of low temperature storage and transportation, most of the mesophilic bacteria that affect the quality of raw milk can effectively inhibit their growth and reproduction under low temperature conditions, thereby reducing the negative impact on the quality of raw milk. Although most of the microorganisms in raw milk are inhibited by the low temperature environment and cannot grow and reproduce normally, there is a type of bacteria (psychrophilic bacteria) that can still reproduce normally under low temperature conditions, which can continue to grow in low temperature environments Breeding, thereby contaminating raw milk. The vast majority of psychrophilic bacteria have poor resistance to heat, and conventional heat sterilization of ra...

AI Technical Summary

Problems solved by technology

Although most of the microorganisms in raw milk are inhibited by the low temperature environment and cannot grow and reproduce normally, there is a type of bacteria (psychrophilic bacteria) that can still reproduce normally under low temperature conditions, which can continue to grow in low temperature environments breeding, thereby contaminating raw milk

Most of the psychrophilic bacteria are poorly resistant to heat, and conventional heat sterilization of raw milk can effectively inactivate them

However, despite the inactivation of the bacteria, the psychrophilic bacteria represented by Pseudomonas fluorescens can secrete thermostable extracellular proteases and lipases. During the storage of dairy products, the protein and fat in milk continue to be decomposed, causing adverse effects such as clots, odor, and fat stratification of milk and dairy products

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