GIFSQ Tools · Module 09 — Fruits, Vegetables, Beverages & Plant Foods · Tool 164 of 500
Browning index from CIE L*a*b* colour readings. Enter the colour values of a cut fruit surface to get the browning index used to compare treatments.
Try sample values — fills the form with the worked example below.
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Browning index
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Chromaticity x
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L* (lightness)
Equation: x = (a* + 1.75 L*) ÷ (5.645 L* + a* − 3.012 b*). Browning index = 100 × (x − 0.31) ÷ 0.17.
Method: Browning index from CIE L*a*b* colour (ISO 11664-4), formula of Palou and co-workers as used in fruit browning studies; colour measured by colorimeter.
Assumptions: L*, a* and b* were measured on the same surface, at the same time after cutting, with the same illuminant and observer.
Limitations: The index is a comparative colour number, not a direct measure of enzyme activity; it cannot separate enzymatic browning from other colour change.
Rounding: Browning index to 2 decimal places; x to 4 decimal places. Intermediate values are not rounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Method: Browning index from CIE L*a*b* colour (ISO 11664-4), formula of Palou and co-workers as used in fruit browning studies; colour measured by colorimeter.
Assumptions: L*, a* and b* were measured on the same surface, at the same time after cutting, with the same illuminant and observer.
Limitations: The index is a comparative colour number, not a direct measure of enzyme activity; it cannot separate enzymatic browning from other colour change.
Rounding: Browning index to 2 decimal places; x to 4 decimal places. Intermediate values are not rounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Worked example: Cut apple: L* 70, a* 2, b* 20. x = (2 + 122.5) ÷ (395.15 + 2 − 60.24) = 124.5 ÷ 336.91 = 0.3695. Browning index = 100 × (0.3695 − 0.31) ÷ 0.17 = 35.02.
Enter values above to see results.
Browning index rises as cut fruit browns. Compare samples measured at the same time after cutting, under the same light and instrument settings. Tool 164 of 500 — GIFSQ
