Comparison of the edible quality of liquid egg with different cooking methods and their antioxidant activity after in vitro digestion

Abstract

The purpose of this study was to compare the edible quality of liquid egg after steaming, baking, frying and microwaving. Texture profile analysis (TPA) and color analysis were used to evaluate the sensory characteristics of cooked eggs. The fat, vitamin A and E, protein and amino acid content of cooked eggs and the antioxidant activity after in vitro digestion were determined to display the variations in nutritional value. TPA results demonstrate that baked egg exhibited a softer and more elasticity texture, with a significant lower hardness of 3234 g than fried and microwaved eggs (p < 0.05). This is also consistent with the results of cohesiveness and chewiness. Consequences from scanning electron microscope showed plentiful honeycomb structure in baked egg, which may be related to the soft and elasticity texture. However, significantly higher contents of fat, vitamins A and E, protein were determined in fried egg (p < 0.05), which may be related to its lower moisture content. The strongest free radical scavenging efficiency for the hydroxyl, the DPPH and the superoxide radical were found in the gastrointestinal digestion of fried egg, with the rate of 95.76%, 81.08%, and 91.08%, respectively. Overall, baked egg showed superior soft and elasticity taste characteristics due to its honeycomb structure, while fried egg exhibited better antioxidant activity because of its high contents in vitamins and amino acids. The above results provide potential approach for the manufacture of pre-cooked eggs and related products using liquid eggs as ingredients.

Keywords: Antioxidant activity; Cooking methods; Liquid egg; Sensory characteristic.