Increased consumption of fresh vegetables high in polyphenols is related to a reduced risk of oxidative stress-induced disease. The objectives of this study were to assess in vitro and/or in vivo antioxidant effects of Korean local spinach, Shinan Seomcho, using hyperlipidemic rats and to evaluate quality characteristics of its powder foods. Hot water (WE) or ethanol extracts (EE) of the spinach were used for in vitro antioxidant activity test and for determining total polyphenol content (TPC), oxygen radical absorbance capacity (ORAC), cellular antioxidant activity (CAA), and antigenotoxic activity. In vivo
antioxidant activity of the spinach extracts was also assessed by means of blood and liver lipid profiles and antioxidant status in rats fed a high fat and cholesterol diet (HFCD) for 6 weeks. The TPC for WE and EE were 1.5±0.0 and 0.5±0.0 mg GAE/g, respectively. The ORAC, CAA, and antigenotoxic activities were shown to increase at higher concentration of WE or EE concentrations. HFCD rats displayed hyperlipidemia and increase of oxidative stress, indicated by significant rises in blood and liver lipid profiles, plasma conjugated diene and liver thiobarbituric acid reactive substances (TBARS) and a significant decrease in the manganese superoxide dismutase (Mn-SOD) level compared with the rats fed normal diet. However, feeding 5% spinach extracts showed a beneficial effect on the HFCD rat, observed by decreasing liver TBARS, inhibiting DNA damage in leukocyte and increasing Mn-SOD level. The resulting antioxidant activities of the spinach diet may provide a useful means to ameliorate high fat and cholesterol diet-induced oxidative stress. Shinan seomcho can help to reduce oxidative stress by regulating antioxidant metabolism and its extracts possibly have potential for preventing DNA damage caused by high-fat cholesterol diet. For this reason, we could use Shinan seomcho as functional food ingredients. Thus, we prepared the processed products with Shinan seomcho to apply its functionality on powder foods such as white bread, Sulgidduk, and chiffon cake.
White bread was prepared with Shinan seomcho powder (SSP). Different ratios of SSP (2, 4, 6 and 8%) were tested to determine the optimal ratio for an acceptable bread. The SSP samples with a control were compared for quality attributes including pH, total titratable acidity, specific volume, baking loss, moisture content, water activity, color, textural characteristics, external and internal surface appearances, and sensory qualities. By consisting of SSP in the bread, the total titratable acidity decreased (pH increased) in comparison of the control, and decreases of specific volume and baking loss were observed as well. However, the total titratable acidities and pHs did not show significant differences among the samples. The moisture content was highest for a substitution level of 8% and it was slightly increased with increased amount of SSP. With an increase of SSP in the bread, the crumb L-value, a-value and resilience decreased, whereas the crumb b-value and hardness increased. In sensory evaluation data of color, flavor, softness, and overall acceptability, the control sample had the highest scores and the 8% SSP sample had the lowest among the samples. With regard to intensity of sensory attributes, the 8% SSP sample had significantly highest values of a grassy flavor, green tea taste, bitterness, astringency, and off-flavor. Therefore, it was suggested that the addition range of SSP for a suitable white bread would be 2∼4%.
Sulgidduk was prepared with Shinan Seomcho spinach powder (2%, 4%, 6%, or 8% SSP), and moisture content, water activity, the appearance observation, the color, texture, and sensory characteristics were evaluated. The moisture content in the control sample was lowest by 38.54% and it was increased with increases of SSP ratios, whereas water activity showed the reverse results. In Hunter color values, lightness was shown to decrease significantly with increases of SSP ratios. In texture, hardness was the lowest by 154.97 g at a substitution level of 4%, while fracturability was the lowest at a substitution level of 8%. The adhesiveness was not significantly different between the control and SSP samples. The springiness significantly increased with increase of SSP ratio. The gumminess and chewiness was highest at substitution level of 2% SSP. In the intensity characteristics of sensory attributes, the grass-flavor, the bitterness and the off-flavor were significantly increased with increase of SSP. The moistness was not significantly different among the samples. The sweetness, color, flavor, softness, and overall acceptability were significantly decreased with increases of SSP ratios. In overall acceptability, all substitution samples had more than average scores. From these results, an acceptable amount of SSP for Sulgidduk would be 2∼4%.
Chiffon cake were prepared with 5%, 10%, 20% and 30% SSP. The specific gravity of chiffon batter tended to increase by adding SSP. Viscosity of chiffon cake batter was significantly increased by adding SSP. Moisture content of the control cake was the highest by 34.42%, which decreased significantly with increases of SSP ratios. Weight of the cake made with SSP was slightly higher in comparison with that of control, but the resulting data did not show significant differences within the samples
The height of the cake added with 30% SSP was the lowest among the samples. Hunter color values of the crust decreased with increases of SSP ratios. The color L and b values of the crumb decreased, but a value increased with increase of SSP. The hardness was significantly depending on the increase of SSP by increasing its value. Fracturability of the cake made with 30% SSP was the highest, while springiness tended to decrease by adding SSP. Cohesiveness increased significantly with decrease of SSP. The sensory intensity of the grass flavor, green tea taste, astringency, and bitterness increased significantly with increase of SSP. Control sample cake was preferred overall to consumers, while the color, flavor, and softness of SSP cakes (particularly 5%∼10% addition samples) were specifically preferred. From these results, suitable mixing range of SSP for chiffon cake made would be 5∼10%.