General Procedure in All Experiments
The process flow diagram of producing oils and deoiled meal from pecan kernels by water is shown in Fig. 1. The pecan kernels were baked for certain minutes (variable studied, 0 to 10 minutes) under a certain temperature (variable studied, 24 to 120 ℃). They were then ground to slurry passed through a sieve (made by Hebei Jiufeng Screen Metal Products Factory, Hebei,China) with a certain mesh (variable studied, 80 to 300 meshes) with a ceramic grinding rod by hands. The slurry (10.00 g) was weighed into a centrifuge tube (20 ml) and mixed with a certain amount (variable studied, 0 to 1.60 mL) of deionized water. The mixture was agitated using a stainless steel rod for certain minutes (variable studied, 0 to 60 minutes) under a certain temperature (variable studied, 24 to 60 ℃) at 60 rpm. Free oil produced was collected by centrifugation at 1435 g for 30 minutes at room temperature three times (the Model 80-2 Electric Centrifuge made by Jintan Medical Equipment Factory, Jintai, China) followed by spiral cold expressing (the BG-03 cold screw expeller made by Aibang Agricultural and Horticultural Machinery Factory, Shanghai, China). Each sample was repeated three times.