2.1 Materials
Commercial walnut butter-1 (SS1, purchased from Shengyuan Agricultural Technology Co., Ltd), commercial walnut butter-2 (SS2, purchased from Tianjin Jizhou Green Food Group Co., Ltd), commercial walnut butter-3 (SS3, Purchased from Nanshizhao Food Group Co., Ltd); defatted walnut meal(purchased from Hebei Chenxing Biotechnology Co., Ltd); medium-chain triglyceride(purchased from Wuhan Kangcan Biotechnology Co., Ltd), diglyceride(purchased from Xi’an Huageng Biotechnology Co., Ltd), and conjugated linoleic acid lipid (Purchased from Qingdao Aohai Biotechnology Co., Ltd, all three FL are food grade). All chemicals were purchased from Sinopharm Chemical Reagent Co.,Ltd. They included: Methyl red indicator, methyl blue indicator, petroleum ether, sodium dodecyl sulfate.