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Agro IndustriesShea Butter Manufacturer, Nigeria
Glossary

Refractive Index

Also written as: RI, n40, refractive index at 40 °C

Summary

Refractive index (RI) is the ratio of the speed of light in a vacuum to its speed in a substance, measured for fats on the melted sample at a stated temperature, usually 40 °C. It is a quick identity check for shea butter.

Refractive index shifts with unsaturation and chain length, so adulteration with paraffin, palm or other fats moves it from the shea range. Always read the temperature — a reading without it is meaningless. Methods are ISO 6320 and AOCS Cc 7-25; the COA interpreter shows the line on a certificate.

Saponification Value

Saponification value is the milligrams of potassium hydroxide (KOH) needed to saponify one…

Iodine Value

Iodine value (IV) is the grams of iodine absorbed by 100 grams of fat

Unsaponifiable Matter

Unsaponifiable matter is the fraction of a fat that does not form soap when boiled with al…

Full explainer: Refractive Index

Refractive index at 40 °C as an identity check for shea butter.

Part of the shea butter glossary · Complete guide to shea butter

Last reviewed September 2026 by EMI Agro Industries QC team.