Cooking oil quality mainly shows in the color, transparency, taste and smell of the oil
Color: The soybean oil with good quality has deep yellow color and oil of normal quality has pale yellow color. Rapeseed oil is in bright yellow or yellow with green. Peanut oil is in light yellow or light orange color. Cottonseed oil is in light yellow color.
Scent: Dig in the oil with a finger and spread the oil in the palm, rub and smell the scent. The oil with good quality should have its own oil flavour without other peculiar smell.
Transparency: The oil with goof quality is transparent and contains less water and impurities. Good vegetable oil should be clear without precipitation and suspended matter after placed for 24 hours.
Taste: The good oil should not have bitter, burnt, rancidity and peculiar taste
It is worth noting that oil’s situations are always varied under different situations. Salad oil should be clear and transparent, colorless or pale yellow. The peanut, soybean and canola oil has translucent pale yellow or orange color. Sesame oil is in orange yellow or brown. The oil gained from soybean, rapeseed, peanut, sesame after the preliminary producing process is in deep color and luster, thick and not edible. Poor transparency, larger viscosity, bubbles of the vegetable oil are often the symbols of metamorphism. Peanut oil will be solidified in winter under low temperature which is normal phenomenon. Thus we should consider the varied situations while indentifying.