Effect of functional lipids on the quality of walnut butter prepared from defatted walnut meal by ball mill grinding

Abstract In this study, walnut butter was produced by mixing functinal lipids with defatted walnut meal. Three kinds of functional lipids（FL）, medium-chain triglycerides (MCT), diacylglyceroe (DG), and conjugated linoleic acid glycerides (CLA), were used to make functional lipids walnut butter(FLWB) and their physical properties as well as microscopic morphology were compared with commercial walnut butters. The FLWBs were prepared by grinding FL and defatted walnut meal through the ball milling technique. The mixing ratios of FL and defatted walnut meal were 6:4, 6.5:3.5, 7:3. It was found that the fluidity of FLWB was increased with the addition amount of FL, but the particle size of FLWB was decreased with the addition amount of DG or CLA. As the additions of DG and CLA increased from 60% to 70%, the D (4,3) of DG-WB and CLA-WB decreased by 36.23% and 20.88%; the flowability index increased by 15.74% and 168.91%. As the addition of MCT increased from 60% to 70%, there was no significant difference in D (4,3) of MCT-WB, but the flowability index increased by 717.34%. Microrheological properties indicated that both FLWB and commercial walnut butter exhibited viscoelastic characteristics. The rheology showed that the FLWB was non-Newtonian pseudoplastic fluids, which was similar to the commercial walnut butter. The DG-WB and CLA-WB were closer to the commercial walnut butter, compared with MCT walnut butter. The microstructure further indicated that the walnut butter with 65% CLA addition was closer to the commercial walnut butter.