FOR PHYSICOCHEMICAL PARAMETERS

Moisture and Insoluble Impurities | Refractive Index | Saponification Value | Iodine Value | Unsaponifiable Matter | Acid Value | TBHQ | Flash Point | Physical Observations | Hexane | Presence of Argemone Oil | Presence of Mineral Oil

Moisture and Insoluble Impurities

Moisture and insoluble impurities may be present in edible oils but these should be as low as possible – Indian Standard and AGMARK have specified the permissible limit at 0.1 per cent for refined oils (expressed and solvent refined). • All brands were within the permissible limit. • Dhara scored highest on this parameter. Refractive Index (at 40 degrees Celsius) Refractive index of oil can be used to detect rancidity. It shall be in the range of 1.4620–1.4640. • All brands were within the specified limit. They were clear and without any haziness. • Dhara scored highest on this parameter. saponification Value

The saponification value helps to detect the presence of other oils/fats. Saponification value of groundnut oil shall be between 188 and 196. • All brands except RRO Primio were within the specified limit. • Dhara scored highest on this parameter as well. Iodine Value The iodine value is a measure of the unsaturated fats. It is expressed in terms of the number of

centigrams of iodine absorbed per gram of sample (% iodine absorbed). Iodine value of groundnut oil shall be in the range of 85–99.

Iodine value of all brands fell within the specified limit. • Dalda scored highest on this parameter.

Unsaponifiable Matter

Unsaponifiable matter shall not be more than 1.0 per cent by weight of groundnut oil.

All brands were within the specified limit.

acid Value

The acid value is the number of milligrams of potassium hydroxide necessary to neutralise the free acids in one gram of sample. Acid value shall not be more than 0.5 for refined oils. For filtered-type oils, the requirement is 6.0.

All brands were within the specified limit.

TBHQ (antioxidant)

Antioxidants are the permitted food additives which when added to food products prevent their

oxidative deterioration for better nutritional stability and quality. FSS Regulations recommend that antioxidants should not exceed 0.02 per cent, or 200 ppm, in concentration. We tested the 10 groundnut oil brands for the antioxidant TBHQ.

• TBHQ was not detected in Dhara, Gemini, Guinea and Gulab; in the rest of the brands it was within the maximum recommended limit of 200 ppm.

Flash Point

The flash point of a volatile material is the lowest temperature at which it can vaporise to form an ignitable mixture in air. At the flash point, the vapour may cease to burn when the source of ignition is removed. It should not be less than 250 degrees C as per Indian Standard. Higher the flash point of groundnut oil, lower is the risk of ignition in the oil.

Flash point of all brands was found to be well above the specified limit.

Hexane

In refined oils, hexane is used to extract the oil from seeds. It shall not be more than 5 ppm as per Indian Standard. For filtered oils, no requirement

has been specified because hexane is not required to extract the oil from seeds. • Hexane was not detected in any of the brands, up to a detection limit of 5 mg/kg.