a decreasing trendp < 0.05
Color As shown in Figure 1 a, with the increase of PPI, a decreasing trend ( p < 0.05) in L* value can be observed, from 52.4 to 46.4. b* value refers to the yellow value.
Color As shown in Figure 1 a, with the increase of PPI, a decreasing trend ( p < 0.05) in L* value can be observed, from 52.4 to 46.4. b* value refers to the yellow value.
However, in the experimental group (3–9%), there was an increasing trend in PT 21 ( p < 0.05) and a decreasing trend in PT 22 ( p < 0.05).