I extract maize kernel for doing enzyme assay but the starch present in the samples gives a higher background OD which makes the assay difficult.
I think you can try centrifugation as we do for starch extraction. It will certainly sediment the starch granules and still retaining the enzymes in the extract.
I think it will be hard to measure amylase activity (I assume this from your question) in a solution with some starch in it. However, you can try to precipitate the protein in the solution first using ammonium sulphate or acetone, and then re-solubilized the precipitate to the initial volume, if you want to measure the activity in the initial volume. A paper by Warner et al. 1991 that measure alpha-amylase activity from maize seed can be found here: http://naldc.nal.usda.gov/download/24404/PDF
If you can give the method that you are using, maybe that will be better for colleagues to understand more about the problem. Hope this help..
addition: I assume that you use Iodine-amylose complex for measuring the enzyme activity. I suggest that you measure the product of hydrolysis by measuring reducing sugar which can be done using DNS, Somogyi-Nelson, or alkaline ferricyanide methods.
My objective here is to get a clean extract after grinding with no colloidal or any other starch which can interere with my OD measurements in the enzyme reaction. In other words, I would like to have a simple and rapid procedure to extract maize soluble proteins with no starch.
If you are dealing with the starch granules, centrifugation as suggested by Himjyoti would be appropriate. If you still have more trouble, you can try to filter it through a 0.2 or 0.1 um filter.
I think you can do acetone precipitation method. First you homogenize the sample in acetone and then filter it with filter paper. The acetone powder preserve it at -80 c. When you want to check the activity just weigh some amount and dissolve in 200mM Tris-Hcl (Ph 8.0). Even if u Electrophoresis also you will get sharp bands with this method. More details read our paper: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3258068/
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