Definition · Quality & analyses

ΔK (Delta-K)

Calculated difference between neighbouring UV absorbances, a marker of added refined oil. For an extra virgin, the ΔK must remain ≤0.01. An anomaly reveals a blend or fraud.

Related terms

K232Ultraviolet absorbance at 232 nm, revealing primary oxidation. For an extra virgin, the value must remain ≤2.50. Required by the EU, optional in the IOC trade standard.K270UV absorbance at 270 nm signalling secondary oxidation and the possible presence of refined oil. Extra virgin threshold ≤0.22. A high value betrays an aged or adulterated oil.

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