Gojongsi(Diospyros kaki Thunb) for dried persimmons was peeled and the skins were thrown away. Persimmon peels, however, have vitamin C, calcium, and fiber as much as persimmon flesh does. They also can be effective in preventing aging because they are rich in phenol component, which blocks free oxygen radicals for disease of every kind. If we use persimmon peels properly, we can promote our health, preventing environmental pollution, or using them commercially.
For this study, an experiment was done for the quality characteristic of cookies which contain persimmon peel powder for recycling. The amounts of persimmon peel powder added in the cookies were about 0, 5, 7, 9, 11%.
The densities of cookies with persimmon peel powder of the control group and the experimental group were 1.25±0.00 and 1.25±0.00∼1.37±0.20 respectively, which indicates the density increases with the added amount. The pH levels were 6.02±0.13 for the control group and 6.01±0.11~5.95±0.25 for the experimental group, which means the pH level decreases with the amount of persimmon peel powder.
The moisture content of the cookies showed significant differences(p<0.05), which were 3.34±0.28 and 2.16±0.08 ~3.31±0.42 for control group and experimental group, respectively.
The spreadabilities and loss rates of cookies increased with the amounts of persimmon peel powder, which shows the significant differences between the two groups(p0.05). The loss rates and leavening rate of cookies decreased with the amount of persimmon peel powder, which indicates the significant differences(p<0.05).
The lightness(L value) of the cookies showed the significant decrease(p<0.05), and the redness(a value)and yellowness(b value) increased with the amounts of persimmon peel powder.
The hardness(kg) of them were 0.847±0.12 for control group and 0.904±0.08 ~1.110±0.18 for experimental one(p<0.05).
In the QDA, the result of sensory characteristics shows the experimental group earned 11% higher for color, flavor, taste, and bitterness, 7% higher for appearance characteristics, and 9% higher for after taste.
Consumer acceptance test shows that the experimental group gained 7% more positive evaluation for color, favor, taste and texture than the control group.
On the grounds of the above experiment above, it is considered that the optimal mixture ratio from the sensory test is 7% of persimmon peel powder in the cookies.