BLADE TYPE HOMOGENIZERS

Although less efficient than rotor-stator homogenizers, blade homogenizers (also called blenders) have been used for many years to produce fine brie and extracts from plant and animal tissue. The cutting blades on this class of homogenizer are either bottom or top driven and rotate at speeds of 6,000 to 50,000 rpm. Blenders are not suitable for disruption of microorganisms unless glass beads or other abrasives are added to the media and then one encounters the same problems as were mentioned above for rotor-stator homogenizers. Many plant tissue homogenizers undergo enzymatic browning which is a biochemical oxidation process which can complicate subsequent separation procedures. Enzymatic browning is minimized by carrying out the extraction in the absence of oxygen or in the presence of thiol compounds such as mercaptoethanol. Sometimes the addition of polyethyleneimine, metal chelators, or detergents.

Blade homogenizers are available for a range of liquid sample sizes from 0.01 ml to multi gallons. Some of the higher rpm homogenizers can reduce tissue samples to a consistent particulate size with distributions as small as 4um as determined by flow cytometric analysis. Accessories for some blenders include cooling jackets to control temperature and closed containers to minimize aerosol formation and entrainment of air.