We recommend de-fatting samples that contain greater than ten percent (>10%) fat content prior to total starch analysis. (defat with petroleum ether three times with 25 mL portions per g of sample).
Record weight loss due to fat. Then it is possible to correct final % result both moisture and fat removed. Store dry, milled sample in a desiccator until analysis is run.
If required, a comparison of values received from one or two samples without de-fatting could be carried out to determine going forward if defatting of the sample type is required.