Surface ruptures of fried batters as influenced by batter formulations

Irregularities and microstructure of the surface of batter coatings play a critical role in oil uptake during deep-fat frying of coated products. The objective of this study was to study the influence of batter formulations on surface irregularities of fried batters. Variable pressure scanning electron microscopy (VP-SEM) was used to study the surface microstructure of batters prepared using different combinations of wheat and rice flours. Images of batter surfaces were captured, and characterized using parameters such as the total number, mean area, the biggest area, ratio and roundness of the generated ruptures on the coating surface after frying. The total number of generated ruptures on the surface of fried batters was significantly (P < 0.05) influenced by the batter coating formulation. Batters formulated only with wheat flour showed the highest number whereas batters formulated only with rice flour showed the least number of holes and cracks. Roundness of the ruptures ranged from 0.19 to 0.35. The higher amount of rice flour used in the formulation of batter, the higher the area of generated holes and cracks on surface was observed. Fat content was directly correlated with the ratio of the observed holes and cracks generated on the surface (|r| = 0.72), whereas moisture loss was correlated with ratio (|r| = 0.67) and mean area (|r| = 0.77).