Measurement of foaming of frying oil and effect of the composition of TG on foaming

We describe a method developed to quantify the amount of foam in frying oils. In this method the foam was quantified by digitizing photographic images that were taken continuously at 1-s intervals; spots showing more than a certain luminance were considered as foam. The ratio of total foaming area to the whole oil surface was integrated to obtain the integration of foam (IF) index as a parameter of the extent of foaming. There was a good correlation between this method and the visual evaluation done by a group of panelists. Furthermore, the foaming tendency correlated with the distribution of TG by M.W. when the IF was plotted against the foam index of TG (FIT), which reflects the M.W. distribution. A correlation was found between the FIT value of oil and foaming on frying, indicating that when the FIT value is small, the oil foams less. Based on the results of this investigation, we have designed a method to obtain edible oils consisting of medium-chain FA that not only are nutritious but also have good cooking properties.