A Study On The Influence Of UHT Processing Equipment On The Concentration Of Lactulose And Furosine In Sterilized Milk

Research on the application of sterilized milk has primarily focused on investigating the effects of sterilization temperature and time,as well as optimizing the associated parameters.However,there is limited research concerning the influence of UHT processing equipment on the concentrations of thermosensitive parameters（such as furosine and lactulose）in sterilized milk.To assess the impact of different UHT processing conditions on the concentrations of these thermosensitive parameters in sterilized milk,this study utilized raw cow’s milk as the primary raw material and employed an industrial-scale UHT system for the heat sterilization process.The study analyzed the content of thermosensitive parameters（furosine and lactulose）and conducted an analysis of the relationship between these parameters.This study has compared the concentration of furosine and lactulose using different UHT milk processing equipment and investigate key processing parameters.Furthermore,the changes in the concentration of furosine and lactulose were monitored at different storage temperatures throughout the entire shelf life.The results revealed the impact of processing equipment,storage temperature,and time on the control of furosine and lactulose,providing a theoretical solution for the production of higher-quality UHT milk.The main study results are as follows.1.The concentration of furosine differed significantly among flash equipment,lowering film evaporator equipment,and RO membrane equipment,with values of 109.23±6.92,98.96±4.247,and86.79±2.19 mg/100g,respectively（P<0.05）.In contrast,the lactulose concentrations were not significantly different among the three equipment types（267.55±43.51,273.98±36.69,and 242.55±32.55 mg/L;P>0.05）.The dehydration equipment had a significant effect on the furosine concentration but an insignificant effect on the lactulose concentration.2.The concentrations of furosine and lactulose were found to increase with the F₀value,with values of 128.29±13.82,167.03±10.79,and 199.35±21.96 mg/100g for furosine and 359.23±27.13,546.61±18.76,and 609.57±22.44 mg/L for lactulose,respectively（P<0.05）.A lower F₀value could reduce the thermal sensitivity index（concentration of furosine and lactulose）of sterilized milk at the same sterilization temperature.3.The concentrations of furosine and lactulose in sterilized milk were significantly different between products with and without an aseptic tank,with values of 108.72±18.17 and 143.42±12.26mg/100g for furosine and 325.02±59.67 and 435.26±41.52 mg/L for lactulose,respectively（P<0.05）.The use of an aseptic tank can reduce the thermal sensitivity index of sterilized milk.4.The concentrations of furosine and lactulose in sterilized milk increased significantly with storage time and temperature,particularly when stored at 35℃.At lower storage temperatures（5℃）,the increase in lactulose and furosine concentrations was not significant.Overall,the longer the storage time（1-6 months）and the higher the storage temperature（20-35℃）,the higher the concentrations of lactulose and furosine were（P<0.05）.