Partial purification and enzymatic characterization of avocado (Persea americana Mill, cv. Hass) lipoxygenase

Detrimental effects on minimally processed fruits and vegetables induced by increased lipoxygenase (LOX) activity are a major concern in the food industry. Partial purification and enzymatic characterization of lipoxygenase (LOX) from avocado fruit (Persea americana Mill, cv. Hass) is presented. Avocado LOX was partially purified by fractional precipitation with ammonium sulfate, followed by anion exchange adsorption. Substrate specificity and effects of temperature, pH and calcium ion concentration on LOX activity were determined. Likewise, the in vitro ability of avocado LOX to co-oxidize β-carotene was determined. LOX showed a higher substrate affinity for linolenic than for linoleic acid. Optimum activity was reached at 40 °C, pH 6.5, and 0.20 mM of calcium ion concentration. Avocado LOX showed β-carotene co-oxidation capability. Considering the optimums and operational ranges established for each studied factor, strategies concerning the inactivation of LOX may be proposed to reduce the detrimental effects on minimally processed avocado products. Additionally, the co-oxidation capability of avocado LOX may be of interest for the avocado industry due to its potential application as a bleaching agent.