Effect of spinach powder added to dough on thermooxidative stability of frying oil and fried product during frying

초록

Effects of freeze-dried spinach powder added to dough on oxidation of frying oil and fried product were studied by determining peroxide (POV), acid (AV) and p-anisidine (PAV) values, contents of polar compound and conjugated dienes, and fatty acid composition. Frying of samples made by sheeting flour dough and cutting to a shape of small square (2 cm x 2 cm) was performed in soybean oil at 160°C for 1 min and repeated every 20 min for 20 h. As the contents of spinach powder in dough increased from 0 to 5, 15 and 25%, POV decreased significantly (p<0.05). There was not much difference in polar compound formation in the oil by the addition of spinach powder to dough; however, there was a tendency to decrease. AV and formation of conjugated dienes in the oil increased when frying the samples with spinach powder. The oxidation of the oil during frying was the lowest when spinach powder was added to dough at 15% caused the lowest oxidation in the products. The results strongly suggest that spinach powder is a good choice to make good quality of flour-based savory snacks due to its antioxidant activity on oil and fried products during frying as well as its excellent nutritional value to provide essential fatty acids, minerals and cellulose.