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