Sample preparation and true density measurement Based on the original moisture content (7.887% w.b.) of the peanut samples, 200 g peanuts in 5 prepared plastic bottles were sprayed with a predetermined amount of distilled water
to obtain samples with 5 needed moisture content levels (10,15, 20, 25, and 30% w.b.). Then, the bottles were sealed and
placed in the refrigerator at 4 C for 7 days, and shaken three times a day to ensure the uniformity of moisture distribution.