Abstract

RESTREPO DUQUE, Ana María et al. Comparison of the oil from Hass varietyavocado cultivated in Colombia, obtainedby supercritical fluids and by conventiona methods: a perspective under quality terms. Rev. Lasallista Investig. [online]. 2012, vol.9, n.2, pp.151-161. ISSN 1794-4449.

Introduction. Oil is the most important component of avocado, achieving levels up to 25% depending on the variety and the maturity. Such oil is known as a very beneficial product for health. Objective. Compare the avocado oil (Persea americana Mill), Hass variety, cultivated in Colombia and obtained by supercritical fluids, with those obtained by coldpressing and soxhlet, under quality terms. Materials and methods. The physical-chemical, bromatological and microbiological characterizations of the fresh avocado was performed and, before the extraction process, the dehydration of the raw material was made by three methods. The frst one was an application of liophylization at -25 °C, 0,05 mbar and a velocity of 0,04 °C/mín. The second was a convective drying at 45°C and the third was a controlled drying with sunlight, with an interior temperature under 45°C. Then, the oil was extracted by supercritical fluids at 25 MPa, 313K, coldpressing and soxhlet, respectively. The oils obtained were tested under terms of acidity index, peroxide index, iodine index, saponification index and specific gravity according to AOCS regulations. Results. There were statistically significant differences with a value of (p> 0,05) in the acidity, peroxide, iodine and saponification indexes, when different methods were applied to extract the avocado oil. The opposite happened with the specific gravity. The avocado oil extracted with supercritical fluids had values of 90,18±0,78; 16,87±1,15; 0,48±0,35; 226,18±1,11 and 0,915±0,04 for peroxide index, acidity index, saponification index and specific gravity, respectively. Conclusion. The extraction with supercritical fluids is the best technique to produce avocado oil, because it is useful to obtain the highest yield, the lowest acidity index, a low oxidation of unsaturated fatty acids and a higher iodine index, if compared with conventional extraction methods such as cold pressing and soxhlet.

Keywords : avocado; supercritical fluids; cold pressing; soxhlet extraction.

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