Effects of process and storage temperature on concentration of Maillard compounds in aseptic cold break tomato paste were evaluated during 12 months of storage time. Cold break tomato paste was processed at 104 ℃ or ...Effects of process and storage temperature on concentration of Maillard compounds in aseptic cold break tomato paste were evaluated during 12 months of storage time. Cold break tomato paste was processed at 104 ℃ or 112℃, aseptically filled into 5 liter bags, and stored at 21 ℃ and 33 ℃. Level of Browning Index, Furosine, and HMF was monitored in the aseptic cold break tomato paste during the storage time. Browning Index, Furosine, and HMF significantly increased in the aseptic cold break tomato paste during storage at 33℃, and there was linear correlation between Browning Index and Furosine （or HMF）. At the lower storage temperature of 21℃, no significant increases were observed. Effects of the process temperature on Browning Index, Furosine, and HMF of aseptic cold break tomato paste were less significant than the storage temperature.展开更多
Tomato processing includes a break step, which involves rapid heating of freshly chopped tomatoes to >90°C for hot break, or 60°C to 77°C for cold break. Pectolytic enzyme deactivation is...Tomato processing includes a break step, which involves rapid heating of freshly chopped tomatoes to >90°C for hot break, or 60°C to 77°C for cold break. Pectolytic enzyme deactivation is believed to be the key element in the hot break step;therefore, pectin content of different products should be qualitatively distinct. The objective of this study was to investigate the effect of hot break versus cold break on the cell-wall pectin of tomato. Cell-wall pectin from hot and cold break tomato products was isolated and analyzed for carbohydrate composition, degree of polymerization, and degree of esterification. The results showed no observable differences in the cell-wall pectin isolated from the two products, indicating that there was no significant pectolytic breakdown of the tomato in the cold break product, and the pectin might not, by itself, contribute to the differences in the final product viscosity resulting from the two processing techniques.展开更多
The existing research of the flatness control for strip cold rolling mainly focuses on the calculation of the optimum adjustment of individual flatness actuator in accordance with the flatness deviation, which can be ...The existing research of the flatness control for strip cold rolling mainly focuses on the calculation of the optimum adjustment of individual flatness actuator in accordance with the flatness deviation, which can be used for general flatness control. However, it does not work for some special rolling processes, such as the elimination of ultra single side edge-waves and the prevention of strip break due to tilting roll control overshooting. For the purpose of solving these problems, the influences of non-symmetrical work roll bending and intermediate roll bending on flatness control were analyzed by studying efficiencies of them. Moreover, impacts of two kinds of non-symmetrical roll bending control on the pressure distribution between rolls were studied theoretically. A non-symmetrical work roll bending model was developed by theoretical analysis in accordance with practical conditions. The model was applied to the revamp of a 1250 6-H reversible universal crown mill (UCM) cold mill. Theoretical study and practical applications show that the coordination utilization of the non-symmetrical work roll bending control and tilting roll control was effective in flatness control when there appeared bad strip single side edge waves, especially when the incoming strip was with a wedge shape. In addition, the risk of strip break due to tilting control overshooting could be reduced. Furthermore, the non-symmetrical roll bending control can reduce the extent of uneven distribution of pressure between rolls caused by intermediate roll shifting in flatness control and slow down roll wear. The non-symmetrical roll bending control technology has important theoretical and practical significance to better flatness control.展开更多
文摘Effects of process and storage temperature on concentration of Maillard compounds in aseptic cold break tomato paste were evaluated during 12 months of storage time. Cold break tomato paste was processed at 104 ℃ or 112℃, aseptically filled into 5 liter bags, and stored at 21 ℃ and 33 ℃. Level of Browning Index, Furosine, and HMF was monitored in the aseptic cold break tomato paste during the storage time. Browning Index, Furosine, and HMF significantly increased in the aseptic cold break tomato paste during storage at 33℃, and there was linear correlation between Browning Index and Furosine （or HMF）. At the lower storage temperature of 21℃, no significant increases were observed. Effects of the process temperature on Browning Index, Furosine, and HMF of aseptic cold break tomato paste were less significant than the storage temperature.
文摘Tomato processing includes a break step, which involves rapid heating of freshly chopped tomatoes to >90°C for hot break, or 60°C to 77°C for cold break. Pectolytic enzyme deactivation is believed to be the key element in the hot break step;therefore, pectin content of different products should be qualitatively distinct. The objective of this study was to investigate the effect of hot break versus cold break on the cell-wall pectin of tomato. Cell-wall pectin from hot and cold break tomato products was isolated and analyzed for carbohydrate composition, degree of polymerization, and degree of esterification. The results showed no observable differences in the cell-wall pectin isolated from the two products, indicating that there was no significant pectolytic breakdown of the tomato in the cold break product, and the pectin might not, by itself, contribute to the differences in the final product viscosity resulting from the two processing techniques.
基金supported by National Natural Science Foundation of China (Grant No. 50534020)
文摘The existing research of the flatness control for strip cold rolling mainly focuses on the calculation of the optimum adjustment of individual flatness actuator in accordance with the flatness deviation, which can be used for general flatness control. However, it does not work for some special rolling processes, such as the elimination of ultra single side edge-waves and the prevention of strip break due to tilting roll control overshooting. For the purpose of solving these problems, the influences of non-symmetrical work roll bending and intermediate roll bending on flatness control were analyzed by studying efficiencies of them. Moreover, impacts of two kinds of non-symmetrical roll bending control on the pressure distribution between rolls were studied theoretically. A non-symmetrical work roll bending model was developed by theoretical analysis in accordance with practical conditions. The model was applied to the revamp of a 1250 6-H reversible universal crown mill (UCM) cold mill. Theoretical study and practical applications show that the coordination utilization of the non-symmetrical work roll bending control and tilting roll control was effective in flatness control when there appeared bad strip single side edge waves, especially when the incoming strip was with a wedge shape. In addition, the risk of strip break due to tilting control overshooting could be reduced. Furthermore, the non-symmetrical roll bending control can reduce the extent of uneven distribution of pressure between rolls caused by intermediate roll shifting in flatness control and slow down roll wear. The non-symmetrical roll bending control technology has important theoretical and practical significance to better flatness control.
