Physicochemical, Antioxidant, and Sensory Characteristics of Sponge Cake Fortified with Quinoa Flour, Oolong, and White Tea Powder

Figure 4

3D surface plots for the effect of variables on sponge cake samples acidity on (a) day 0, (b) day 7, (c) day 14, and (d) day 21 of storage. (OT: oolong tea powder; WT: white tea powder; QF: quinoa flour).

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(b)

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(d)