Avocado (Persea americana Mill.) oil produced by microwave drying and expeller pressing exhibits low acidity and high oxidative stability

Abstract

The influence of drying and extraction on the quality of Hass avocado oil was investigated in this study. Pulp from ripe avocados was ground and dried under microwaves or oven drying with forced air circulation. Pre‐treatment with pectinolytic enzymes in the oven‐drying stage was also assessed. Avocado oil was extracted using expeller pressing or solvent extraction, with petroleum ether or ethanol. Oil from pressed and microwave‐dried avocado pulp presented the lowest acid (0.2 ± 0.02% oleic acid) and peroxide values (4.79 ± 0.004 mEq O2/kg) and the highest oxidative stability (20.8 ± 1.63 h) in contrast with the oil from ethanol extraction (0.42 ± 0.02% oleic acid, 12.2 ± 0.20 mEq O2/kg, and 3.22 ± 0.14 h, respectively). Fatty acid composition did not differ significantly (p > 0.05) between the processes. Thermogravimetric analysis (TGA) revealed that pressed oils were typically moisture free and presented mass losses characteristic of fatty acid and triacylglycerol degradation. Pressing avocado pulp dried under microwaves stands out as a promising alternative for avocado oil processing, as it produces oil with low acidity and high oxidative stability that is appropriate for consumption as an edible oil.Practical applications: Combining microwave drying and pressing of avocado pulp led to a superior quality avocado oil, in terms of acid value, peroxide value, and oxidative stability. This procedure is a promising technology to obtain solvent‐free avocado oil with potential uses in cosmetic, pharmaceutical, and gourmet food products.Hass avocado oil extracted by a combination of microwave drying and pressing presented the best quality.