Study On Processing Technology And Product Development For Long Shelf Life Cheese

Cheese has a long history and rich nutrition,making it an ideal healthy meal.However,cheese is prone to spoilage during storage and has a short shelf life,which has a certain impact on businesses and consumers.In this paper,the effects of vacuum drying,dehydration,ultra-high pressure sterilization and oily heat sterilization on the quality and shelf life of cheese were studied.The results showed that on the basis of ensuring product quality,the four technologies can extend the shelf life to a limited extent,and achieve the goal of quality enhancement.The specific results are as follows:?1?Hydration of cheese at room temperature and the quality change of products during shelf life were studied.Low field nuclear magnetic resonance and its imaging technology were used to analyze the lateral relaxation time T₂ of the cheese during vacuum drying,and the change of the peak area A_2xx was analyzed to reveal the law of the internal water migration and establish a dynamic model of cheese moisture change.A curd cheese block with a diameter of 4.8 cm,a height of 1 cm,and a weight of 20 g made of fresh cow's milk is dried at 50°C,60°C,and 70°C under vacuum,and dried for 2 h,3 h,4Samples were taken after h and 5 h to analyze the low-field nuclear magnetic resonance lateral relaxation time?T₂?and low-field nuclear magnetic imaging;meanwhile,the dried samples were placed at 37°C for a 7-day accelerated shelf life test,and the protein hydrolysis of the cheese was regularly detected Indexes such as degree,total number of colonies,color difference,texture,sensory quality and so on.The results show that,in the vacuum drying process,increasing the temperature can significantly increase the drying rate and accelerate the migration of bound water,difficult-to-flow water,and free water.During the drying process,the free water and bound water change before the hard-to-flow water,and the water balance time is reduced from 330 min to 210 min.During the accelerated storage of the product,the total number of bacteria did not change significantly;the color difference values L^*decreased from 92.75 to 91.78,the a^*value increased from 0.63 to 1.09,the b^*value increased from 13.25 to 15.08,and the?E decreased from 93.69 to 93.13;With the extension of the drying time,the hardness of the cheese increased significantly?P<0.05?.During storage,the cheese has a crisp and loose taste and a strong milk flavor,which basically meets the requirements of room temperature cheese preservation and circulation.?2?A study was conducted to extend the shelf life of mozzarella cheese using ultra high pressure?HPP?technology.Using different pressures?500 MPa,600 MPa?and time?10 min,20 min?for ultra-high pressure treatment,the effects of HHP on the basic ingredients of Mozzarella cheese such as pH,water activity,color difference,and physical and chemical properties were studied.The results showed that HHP had no significant effect on the composition of Mozzarella;the microstructure of Mozzarella cheese changed after HHP treatment,which resulted in the increase of the pH of the cheese,the decrease of the meltability and the increase of the stretchability;after 120 days of storage,the HHP treatment group only had 500 MPa has microbial growth,and HHP can inhibit protein hydrolysis;there is no significant difference in cheese melting,but due to protein hydrolysis,cheese stretchability is reduced.Compared with the untreated group,HHP can maintain the quality of cheese and extend the shelf life of cheese.?3?The effect of heat treatment on the quality and shelf life of Halloumi cheese was studied.Using different temperatures and times such as:high-temperature sterilization treatment,after storing at37?for 7 days,the total number of colonies and sensory evaluation of the cheese,on the basis of ensuring product quality,select the optimal sterilization temperature and sterilization time.The results show that the higher the sterilization temperature and the longer the sterilization time,the better the sterilization effect?temperature time?.However,if the temperature is higher than 120°C and the time is higher than 15min,it will cause great damage to the cheese's tissue state and taste.According to the total colony and sensory evaluation,the sterilization temperature is 120°C and the sterilization time is15min,the organization is tight and elastic,the color is bright and uniform,and the color,fragrance and taste are excellent.This article determines the sterilization methods of cheeses with different characteristics,and clarifies the effects of different sterilization process conditions on the physical properties,sterilization effect,and product characteristics of cheeses.It has important practical significance for extending the shelf life of cheeses.?4?In this experiment,the key ingredients of spreadable cheese sauce were selected for single-factor experiment,and the sensory evaluation score was used as the index for screening.Based on the single-factor experiment,the response surface method was adopted to establish the amount of cheese,the amount of emulsified salt,and the addition of stabilizer.The regression equation model of the quantity to the sensory evaluation score has been tested and the model is effective and accurate.Therefore,it can be used to analyze and predict the impact of the above factors on the sensory evaluation score,combined with the analysis of single factor and response surface experimental results to determine the best spreadable cheese sauce The suitable processing technology is:20%cheese addition,0.72%emulsification salt addition,0.40%stabilizer addition,theoretical value score 92,the average value of 3 verification experiments is 91.5,basically consistent with the predicted value results.The cheese sauce has uniform color and luster,uniform texture,moderate hardness and good spreadability.