Effect of Oil Type and Emulsifier on Oil Absorption of Steam-and-fried Instant Noodles.

Abstract

The effects of four different frying oils and three emulsifiers on oil absorption by steam-and-fried instant noodles were evaluated. The blended oil (high oleic sunflower oil/soybean oil/palm oil = 24:25:1 (v/v/v)) containing approximately 50% oleic acid was chosen as the proper frying oil due to lower oil absorption by instant noodle compared to palm, soybean, and high oleic sunflower oils. Among the four oils, the interfacial tension between high oleic sunflower oil and instant noodle was the lowest (0.073 mN/m), resulting in the highest oil uptake (15.47%), while the lowest interfacial tension (0.30 mN/m) between blended oil and instant noodle resulted in the lowest oil uptake by the fried product (12.63%). Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) were used to observe surface properties and oil distribution. The instant noodle fried in blended oil was found to have uniform oil distribution and smooth surface. After selecting the proper frying oil, three emulsifiers (soybean lecithin, Tween-80, Span-80, at 0.2% (v/v)) were added to the blended frying oil. Adding emulsifier into frying oil significantly decreased the interfacial tension between frying oil and instant noodle. Among the three emulsifiers, addition of soybean lecithin resulted in the lowest interfacial tension (0.010 mN/m) and the highest oil uptake (18.36%). Therefore, from this study, we do not recommend adding emulsifier into frying oil.