Measuring the Refractive Index of Oils and Fats | AOAC 921.08

Refractive index of edible oils and fats | AOAC 921.08


Refractive index or butyro value of edible oils and fats: Measure quickly with a refractometer

Refractive index of Edible Oils and Fats
Refractive index of Edible Oils and Fats

Refractive Index of Edible Oils and Fats, why and how to measure it?

Fats and oils are macronutrients that have a very varied composition. For the industry, it is important to know the origin and concentration of its main elements. For example, oil refineries depend on many oils and fats whose origin is different and unknown. Therefore, it is necessary to find out the identity of the product, and for this the refractive indexes or butyro values are used.

The fastest and most accurate techinique to measure it, is by using a digital butyro refractometer with automatic temperature control such as the Excellence Refractometers. Less than 2mL of sample is necessary and the result is delivered in a couple of seconds

What is the index of refraction of the oil?

Each oil has a specific refractive index measured at a certain temperature, so we can differentiate them. Some of the refractive indices of important oils are described below at 20ºC.

  • Peanut Oil: 1.460 - 1.465
  • Maize Oil: 1.465 - 1.468
  • Mustard Oil: 1.461 - 1.469
  • Sesame Oil: 1.465 - 1.469
  • Soybean Oil: 1.466 - 1.470
  • Sunflower Oil: 1.461 - 1.468
  • Palm Oil: 1.458 - 1.460 (at 40 °C)

Source: Codex Alimentarius: Fats, Oils and Related Products - FAO, Rome (1993)

Download our application to learn how easy is measuring refractive index of oils and fats using a METTLER TOLEDO refractometer.
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