2. 4 Color of walnut butter
The determination of color was referenced to a previous method (Sun et
al., 2015). The color parameters of walnut butter were determined with a
colorimeter (Ultrascan VIS, HuntereLab, USA). Where L* reflected the
brightness of the product, a* indicated a red-green value and b*
indicated a yellow-blue value. The measurements were repeated at least
three times for each sample.