An agricultural waste, pomegranate (Punica granatum L.) peel is known to be rich in total phenolics, which are flavonoids having strong antioxidant effects. In this study, pomegranate peel sponge cakes were prepared with varying ratios of freeze dried pomegranate peel powder (0, 1, 3, 5, 7% (w/w)) to examine their effect on quality characteristics, retrogradation and antioxidant activities. The specific gravity and moisture contents of 3, 5, and 7% pomegranate peel powder showed higher values than the control and 1% group. Addition of pomegranate peel powder increased the batter yield, while there was a significant decrease in baking loss. Increasing pomegranate peel powder content significantly decreased the lightness (L) (from 75.03 to 57.04) and pH values, whereas redness (a), yellowness (b) and ΔE were increased. Increasing concentration of the peel powder also increased the hardness and chewiness, while the springiness and cohesiveness decreased. Considering the Avrami equation, Avrami exponene (n) decreased from 1.8055 (control) to 0.9199 (7% pomegranate peel powder). Time constant (1/k) was lowest in control (at 17.64) and highest in the 7% group (39.84). Total polyphenol, flavonoid content, DPPH and ABTS radical scavenging activities significantly increased with increments in the content of pomegranate peel powder. A sensory evaluation by the 7-point scaling method showed that the sponge cake containing 7% pomegranate peel powder had the highest scores in color, flavor, sweetness, chewiness and overall acceptability. Hence, it is considered that sponge cake supplemented with 7% pomegranate peel powder is the most appropriate for quality characteristics, retrogradation and antioxidant activities.

This study investigated the quality characteristics and antioxidant activities of gluten-free cookies containing teff flour. By substituting 0% (control), 25% (TF25), 50% (TF50), 75% (TF75), and 100% (TF100) of wheat flour with teff flour, five samples were produced. Baking loss rate was the highest in TF25 at 13.76% and the lowest in TF75 at 4.03%. Spread factor was significantly higher in cookies made with teff flour (83.00~85.00) than in the control (81.33) (p<0.05). There was no significant difference in density among the samples at 1.17~1.25 g/mL (p<0.05); however, pH significantly decreased at 6.42~6.04 (p<0.05). While the L-value and b-value significantly decreased with the amount of teff flour, the a-value significantly increased (p<0.05). The ΔE value was the highest in the control at 31.31 and the lowest in TF100 at 58.69. Hardness was the highest in the control at 42.04 N than in cookies containing teff flour. The content of polyphenols was the highest in TF100 at 3.37 μg GAE/mg and the lowest in the control at 1.32 μg GAE/mg. The content of flavonoids was the highest in TF100 at 3.66 μg QE/mg and the lowest in controls at 0.45 μg QE/mg. The value of DPPH IC50 was the highest in the control at 3,723.00 μg/mL and the lowest in TF 100 at 405.27 μg/mL. The value of ABTS IC50 was the highest in the control at 1,822.32 μg/mL and the lowest in TF100 at 529.30 μg/mL. In sensory evaluation, while control, TF75, and TF100 had a higher score in appearance at 5.52~5.60, all samples had no significant differences in flavor, sweetness, savory taste, chewiness, and overall acceptability (p<0.05). These results showed that the gluten-free cookies containing teff flour can improve the quality characteristics and antioxidant activities of a cookie. We concluded that gluten-free cookies containing 100% teff flour are desirable.

Chia (Salvia hispanica L.) seed, originated from Central America, is a nutritious food especially rich in dietary fiber and protein. In this study, we investigated the quality and sensory characteristics of Yanggang with chia seed powder (CSP). Red bean paste was replaced with CSP at 0% (Control), 1% (CSP1), 2% (CSP2), 3% (CSP3) and 4% (CSP4). The pH values of chia seed Yanggang tended to decrease from Control (6.84) to CSP4 (6.67); whereas, the moisture contents of Yanggang samples tended to increase. The soluble solid contents of CSP4 were the highest (3.33 ˚Bx), as compared to the Control which showed the lowest values (2.77 ˚Bx). In the CSP-added groups, the L-value (lightness), a-value (redness) and b-value (yellowness) were increased, while the ΔE (total color difference) was decreased, as compared to the control group. Hardness and springiness were both increased from control (49.77 g/cm2 and 464.80%, respectively) to CSP4 (72.21 g/cm2 and 532.43%, respectively). However, cohesiveness decreased from control (47.41%) to CSP4 (37.34%). Chewiness and adhesiveness showed no significant group-wise difference (p<0.05). Total polyphenol content ranged from 7.23 to 10.73 mg GAE/100 g, with a lower ABTS IC50 of the CSP-added groups than that of the control group. Samples from the CSP-added as well as Control groups showed no significant differences among all items on the sensory evaluation test, except flavor. The results indicated that CSP had significant effects on the soluble solid contents and texture of Yanggang. Thus, the addition of 2% of CSP is desirable for making Yanggang.

This study investigated the quality characteristics, antioxidant activities, and retarding retrogradation of sponge cakes made with 0%, 1%, 3%, 5% and 7% pumpkin (Cucurbita moschata Duch.) leaf powder. Specific capacity significantly increased with the addition (0.33~0.38), but baking loss and dough yield were not significantly different (p<0.05). In color, there was a decrease in the L-value, a-value and b-value, but △E increased in proportion to the amount of pumpkin leaf powder. Moisture content increased in the 0~3% additions, from 27.90~31.68%, but decreased in 5% and 7% (22.37% and 28.15%, respectively). pH tended to decrease significantly according to the amount of pumpkin leaf powder (p<0.05). Hardness increased with the addition of pumpkin leaf powder, and pumpkin leaf groups presented higher springiness and cohesiveness than the control. Chewiness was not significantly differ (p<0.05). In retarding retrogradation, Avrami exponent (n) showed that addition of 5% (0.1329) had more retarding retrogradation effect than the control (0.4319), whereas time constant (1/k) showed both 3% (100.00) and 5% (70.42) addition had more effect than control (18.45). Total phenols and flavonoids content increased proportionate to the addition levels. ABTS radical scavenging activity tended to increase according to the level of pumpkin leaf powder. In sensory properties, 5% addition showed maximum color, and 3% addition had the highest scores in flavor, moistness, sweetness, chewiness and overall acceptability. These results suggested that pumpkin leaf was a good addition to improve the quality characteristics, health and sensory preferences. The most appropriate proportion to have the effect of retarding retrogradation in sponge cake is 3%.

Black tomato (Lycopersicum esculentum) is known to have more β-carotene, lycopene, and vitamin C than general redcolored tomatoes. In this study, we evaluated the quality properties, antioxidant activities and sensory characteristics of black tomato cookies. Cookies were prepared by replacing 0, 1, 3, 5, and 7% of flour with black tomato powder. Density of black tomato cookies tended to be decreased between control (1.20) and 3% added groups (1.12). pH value was decreased from control (6.66) to 7% added group (5.16). Spread factor and loss rate were increased with increasing amounts of black tomato powder. Hardness was gradually increased from 107.77 g/cm2 in control to 170.50 g/cm2 in 7% added group. Color measurement indicated that L-value (brightness) was highest in control (70.46) and lowest in 7% added group (45.23); whereas, a-value (redness) increased while b-value (yellowness) tended to decrease with increasing amounts of black tomato powder. Total polyphenol contents and DPPH radical scavenging activities were directly proportional to the amount of black tomato powder. Consumer preference scores in color and flavor of black tomato powder added group were higher than those of control. Characteristic strength test was not significantly different among the groups. Overall, the results indicated that adding 5% black tomato powder is desirable for making black tomato cookies.