Heat treatment of milk may cause whey proteins and caseins to form aggregates. These soluble and micellar aggregates and their other properties (size, composition, shape, etc.) can affect the techno-functionalities to...Heat treatment of milk may cause whey proteins and caseins to form aggregates. These soluble and micellar aggregates and their other properties (size, composition, shape, etc.) can affect the techno-functionalities to the milk, conferring interesting or negative features depending on the application in dairy industries. In this study, we propose a new approach to characterise those protein aggregates. SDS-agarose electrophoresis is followed by the calculation of a retention factor (Rf) for each protein spot. Rf allows milk aggregates to be compared qualitatively under the same conditions. This method could be transposed to the dairy industry for a better knowledge of the milk subsequent to heat treatment.展开更多
Rice-glucose-lysine blend was extruded using a co-rotating twin-screw extruder.The effects of different extrusion conditions on the browning properties of extrudates were analyzed and compared using the CIE Lab system...Rice-glucose-lysine blend was extruded using a co-rotating twin-screw extruder.The effects of different extrusion conditions on the browning properties of extrudates were analyzed and compared using the CIE Lab system of measurement.Extrusion process variables included moisture content,screw speed,barrel temperature,and screw geometry.The influence of product temperature on the browning property of extrudates was significant(P<0.05).The color parameters were related to product temperature by a 4th degree polynomial(P<0.05).Hunter color scale values(L*,a*,b*,-L*a*/b*,Whiteness Index,and Yellowness Index)from extruded samples were analyzed to relate to extrusion process variables.Product temperature and browning properties were modeled and tested at various screw configurations and extrusion conditions.Product temperature and browning property models were verified using different screw geometries and other processing conditions with reasonable accuracy.展开更多
文摘Heat treatment of milk may cause whey proteins and caseins to form aggregates. These soluble and micellar aggregates and their other properties (size, composition, shape, etc.) can affect the techno-functionalities to the milk, conferring interesting or negative features depending on the application in dairy industries. In this study, we propose a new approach to characterise those protein aggregates. SDS-agarose electrophoresis is followed by the calculation of a retention factor (Rf) for each protein spot. Rf allows milk aggregates to be compared qualitatively under the same conditions. This method could be transposed to the dairy industry for a better knowledge of the milk subsequent to heat treatment.
文摘Rice-glucose-lysine blend was extruded using a co-rotating twin-screw extruder.The effects of different extrusion conditions on the browning properties of extrudates were analyzed and compared using the CIE Lab system of measurement.Extrusion process variables included moisture content,screw speed,barrel temperature,and screw geometry.The influence of product temperature on the browning property of extrudates was significant(P<0.05).The color parameters were related to product temperature by a 4th degree polynomial(P<0.05).Hunter color scale values(L*,a*,b*,-L*a*/b*,Whiteness Index,and Yellowness Index)from extruded samples were analyzed to relate to extrusion process variables.Product temperature and browning properties were modeled and tested at various screw configurations and extrusion conditions.Product temperature and browning property models were verified using different screw geometries and other processing conditions with reasonable accuracy.
