| Marinated beef is a kind of traditional cooked meat products made from beef as the main raw material through the processes such as pickling,boiling,marinating.It is highly favored by consumers due to its rich nutrition and strong aroma.Currently,marinated beef is mainly produced in small workshops.The traditional marinating technology has the problems of long time,low efficiency,and difficulty in ensuring the quality of final products.In addition,it is prone to corruption and deterioration,and has a short shelf life,which poses a potential safety hazard.Ultrasound is a new green and easy-to-operate food processing technology that can damage the muscle fiber structure and promote the penetration of brine in the muscles.At present,there are limited reports on the effects of ultrasonic-assisted marination on the beef quality,and its effectiveness is still unclear.Therefore,in this paper,the ultrasonic-assisted marination technology was applied to process beef products,and the process conditions were optimized by a response surface methodology based on the quality assessment of final beef products.Furthermore,the effects of different sterilization methods on the quality of marinated beef products were further evaluated,in order to provide technical support for the processing and storage of marinated beef products as well as provide theoretical basis for the development of deep processing industry of marinated meat products.The main research contents and results are as follows:1.Optimization of ultrasonic-assisted marinated beef processing technology.A single factor experiment was conducted to explore the effects of ultrasonic power,ultrasonic time,and marinating temperature on the tenderness(shear force)and sensory evaluation of beef.Then,a response surface method was used to optimize the ultrasonic-assisted marinating process conditions with sensory evaluation as response value.The results of single factor test showed that the marinated beef had a lower shear force value and higher sensory score under the conditions of ultrasonic time of 30 min,ultrasonic power of 750 W,and marinating temperature of 70℃.On this basis,the ultrasonic-assisted marinating technology was optimized,and the P value of the regression model was<0.001,and R2 was>0.9,indicating that the model had a good fitting degree.The results of the model indicated that the degree of single factor affecting the sensory score of marinated beef was in the order of B(marinating temperature)>C(ultrasonic power)>A(ultrasonic time),the degree of interaction factors affecting the sensory score of marinated beef was in the order of AB>BC>AC,and the degree of secondary factors affecting the sensory score of marinated beef was in the order of B2>A2>C2.The optimal ultrasonic-assisted marinating process parameters were obtained as follows:marinating temperature 65℃,ultrasonic power 620 W,and ultrasonic time 28 min.The verification test found that under the ultrasonic process parameters,the sensory score of marinated beef was the highest,indicating that the optimization results were feasible.2.Effects of ultrasonic-assisted marination on the quality of final beef products.The group without ultrasonic technology was set as a blank group and compared with the group treated with the optimal ultrasonic technology conditions.The quality indexes(cooking loss rate,pH,color,tenderness,texture,MFI,TBARS,SDS-PAGE,and microstructure),nutritional indexes(fatty acids,free amino acids),and flavor indexes(GC-MS,electronic tongue and sensory evaluation)were measured to investigate the effects of ultrasonic-assisted marinating technology on the edible quality of beef.The results showed that the cooking loss of beef products decreased from 45.49%to 38.78%after ultrasonic-assisted treatment(P<0.05).The pH value was 6.11,and the L*value was increased significantly,the a*value was decreased significantly,while the b*value did not change significantly.The shear force and hardness of ultrasonic-marinated beef were 34.67 N and 36.26 N,respectively,which were significantly lower than those of the control group(P<0.05).The TBARS value of ultrasonic-marinated beef was 0.32 mg/kg(P<0.05).Based on the analysis of electronic tongue,fatty acid,amino acid,and flavor,the intensity of salty taste in ultrasonic-treated group was 41.73(P<0.05),and the intensity of umami taste was 16.99(P<0.05).The total fatty acids,saturated fatty acids,and monounsaturated fatty acids were 107.27 mg/g,54.87 mg/g,and 23.72 mg/g respectively,which were significantly lower than those in the control group(P<0.05),and the polyunsaturated fatty acids were 28.68 mg/g,which were significantly higher than those in the control group(P<0.05).The effect of ultrasonic treatment on the free amino acids was not significant(P<0.05).Twenty-two kinds of flavor compounds were detected in the ultrasonic-treated group.Compared with the control group,the flavor compounds of alkyl olefins and esters increased significantly(P<0.05),the aldehyde compounds decreased significantly(P<0.05),while the alcohol and ketone compounds did not change significantly(P>0.05).The above results show that ultrasonic-assisted marination can effectively improve the quality and flavor of the beef products.3.Impacts of different sterilization methods on the storage quality of marinated beef.The vacuum-packed marinated beef without sterilization treatment was set as a control group,whereas the marinated beef products with low-temperature sterilization(80℃,30 min)or irradiation sterilization(60Coγ ray 4 kGy)were set as the treatment groups.After vacuum packaging,the beef samples were stored at 4℃ for 0,7,14,21,and 28 d.During the storage period,the total number of colonies,pH,color,and texture of marinated beef products were determined.The total number of colonies in the irradiation sterilization group(60Co-γ4 kGy)at 4℃ for 28 d was 3.5 lg CFU/g,which was always less than 5.0 lg CFU/g during the storage period and did not reach the end of shelf life.However,the pH value of marinated beef after irradiation was not significantly decreased(P>0.05),while the L*value decreased from 48.5 to 44.5,A*significantly increased to 9.2,and the change of b*value was not obvious,suggesting that the color stability of beef products was good.In the irradiation sterilization group,the hardness decreased significantly on the 21st day of storage(P<0.05),and the elastic value increased significantly on the 28th day of storage(P<0.05).The TBARS value of irradiation sterilization group was 0.46 mg/kg,which was significantly lower than that of lowtemperature sterilization group and control group(P<0.05).At the 28th day,the TVB-N value of the irradiation sterilization group was 14.20,lower than the corruption limit.The sensory score of irradiated samples did not change significantly at the initial stage of storage(P>0.05),and the sensory score was 27.50 at 28 d,which was significantly higher than that of lowtemperature sterilization group and control group(P<0.05).The above results show that irradiation sterilization can effectively improve the quality of marinated beef,so that it can maintain better quality and nutritional value during storage.In conclusion,this study optimized the parameters of ultrasonic-assisted marinating,and explored the influence of ultrasonic-assisted marinating on the quality of beef products.The results demonstrated that irradiation sterilization could effectively prolong the shelf life of marinated beef,providing a theoretical basis for the industrial production of marinated beef. |
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