Lipoxygenase activity assay

Lipoxygenase (LOX) is a key enzyme involved in the oxidation of polyunsaturated fatty acids, including linoleic and linolenic acids. This enzymatic reaction results in the formation of hydroperoxides, precursors to volatile compounds responsible for flavor, but also for rancidity and loss of nutritional quality.

The measurement of lipoxygenase activity therefore makes it possible to:

• Evaluate the oxidative stability of vegetable oils;
• Check the freshness of seeds, legumes or enzyme extracts;
• Characterize functional ingredients rich in natural enzymes;
• Identify enzymatic sources for nutraceutical or cosmetic formulation.

This is a particularly useful analysis in plant sectors sensitive to oxidation, such as products based on soy, wheat, peanut or sunflower.

Analysis method

The analysis of lipoxygenase activity is based on spectrophotometric techniques, allowing the appearance of oxidation products to be monitored in real time:

• Reading at 234 nm: this wavelength allows the quantification of hydroperoxides formed during the enzymatic reaction, a direct signature of LOX activity.
• Titrimetry or enzymatic kinetics: depending on the matrices and needs, the method can be coupled with time monitoring for more precise quantification.

Results are usually expressed in enzyme units (U/g or U/mL) or as absorbance change per minute.

Affected matrices

Lipoxygenase activity assay applies to many agri-food and plant matrices, including:

• Vegetable oils (soybean, sunflower, rapeseed, etc.) – control of oxidation and freshness;
• Seeds and flours – monitoring of viability, heat treatment or storage;
• Plant enzyme extracts – standardization of products for functional purposes;
• Processed or nutraceutical products – quality control and labeling validation.

Industrial and regulatory interest

In the food industry, lipoxygenase plays an ambivalent role:

• Positive: under certain conditions, it contributes to the development of characteristic aromas (e.g.: bread, green tea, beer);
• Negative: it accelerates oxidative rancidity, reduces nutritional value (loss of vitamins, destruction of essential fatty acids) and alters the color or odor of finished products.

Its dosage is therefore a very useful quality indicator, particularly in products rich in lipids or intended for long-term storage.

Recommended Related Analyses

For a complete understanding of oxidation or enzymatic activity phenomena, the following analyses can be carried out in addition:

• Determination of free acidity – indicator of rancidity in oils and fats;
• Peroxide assay – measurement of primary lipid oxidation;
• Determination of linoleic acid – preferred substrate of lipoxygenase;
• Antioxidant activity assay (DPPH, ORAC, ABTS) – to assess protective capabilities against oxidation.

YesWeLab: your partner for enzymatic testing

At YesWeLab, we provide you with a complete solution for managing your enzyme analyses. Thanks to a network of accredited partner laboratories (ISO 17025, COFRAC, etc.), we ensure the quality, reliability, and traceability of each analysis.

Our digital platform allows you to:

• Manage your analysis requests simply;
• Track your samples in real time;
• Access your reports and results as soon as they are validated.

Need a lipoxygenase test?

Add this service to your online quote or contact our scientific team for assistance in selecting your analyses.