[Lipoxygenase and trypsin inhibitor inactivation in soymilk processing by direct milling and ultra high temperature (DM-UHT)].
Soymilk production by a new process based on Direct Milling of soy grits and Ultra High Temperature (DM-UHT) has been studied at laboratory scale in order to evaluate solids and protein extraction, lipoxygenases (LO) and Trypsin Inhibitors (TI) inactivation during milling and heat-treatment steps. For TI measurements in soy extracts and soymilk a modification of the classical Kakade method (17) was used. Highest extraction yields were accomplished at 70 degrees C and 2 minutes milling of soy grits. LO was appreciably inactivated when using, as dispersing medium for milling, 0.01M sodium carbonate (Residual Activity 14%) instead of water (Residual Activity 46%), so in this way lower levels of undesired substances can be generated. LO destruction in the resulting suspension was finished by a short heating (30 seconds) from 70 degrees C to boiling temperature (96 degrees C). On the other hand, TI were not fully inactivated in milling nor even in the steaming step at 96 degrees C for many minutes. The TI were inactivated to the accepted levels for soymilk in the final UHT step at 135 degrees C and 2 minutes, being possible at the same time to carry out the simultaneous microorganisms destruction.
Geronazzo
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Universidad Nacional de Salta, Buenos Aires, Argentina.
Macoritto
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Mercado
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Toro
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Cuevas
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D005511:Food Handling / Q000379:methods*; D008084:Lipoxygenase; D013025:Glycine max / Q000737:chemistry / Q000201:enzymology / Q000382:microbiology; D014361:Trypsin Inhibitors
D014361:Trypsin Inhibitors; D008084:Lipoxygenase