Characterization, isolation and identification of compounds with antioxidant activity of Hass and Fuerte avocados cultivars

Author(s)

Maria Augusta Tremocoldi

• Document type: Doctoral Thesis
• Press: Piracicaba.
• Institution: Universidade de São Paulo (USP). Centro de Energia Nuclear na Agricultura (CENA/STB)
• Defense date: 2015-04-15

Examining board members

Severino Matias de Alencar; Erica Regina Daiuto; Tatiane Luiza Cadorin Oldoni; Jonas Augusto Rizzato Paschoal; Marta Helena Fillet Spoto

• Advisor: Severino Matias de Alencar

Abstract

Fruits are important sources of nutritional substances and are rich in compounds with functional features that can be identified as good sources of natural antioxidants. The avocado is a tropical fruit with attractive nutritional and organoleptic characteristics, especially the amount of lipids with high content of unsaturated fatty acids that provide health benefits. Furthermore, agroindustrial residues such as peels and seeds obtained during processing contain bioactive compounds. However there are no studies about evaluate the capacity for scavenging reactive oxygen species, the anti-inflammatory activity and the phenolic composition of fruits and residues from avocado according to the scientific literature. A source of polyunsaturated fatty acids, the fruit must contain a variety of antioxidants, phenolic compounds among which, for protection and integrity against oil oxidation. The goal of the present study was to characterize, isolate and identify substances with antioxidant activity of the pulp, peel and seed of Hass and Fuerte avocados cultivars; evaluate the capacity for scavenging reactive oxygen species, the anti-inflammatory activity. The total phenolics content was measured by the Folin-Ciocalteu method. The methods for evaluating the antioxidant activity used were the DPPH free radical and ABTS, ?-carotene bleaching, reduction of Fe3+, oxidative stability in Rancimat, evaluate the capacity for scavenging reactive oxygen species by ORAC, superoxide anion and hypochlorous acid. Peels and seeds of both cultivars showed higher antioxidant activity than the pulp of the fruit. Compounds present in peels and seeds from both cultivars were quantified through LC-DAD-UV and LC-MS/MS and confirmed through RMN. The compounds exhibiting the greatest antioxidant activity were trans-5-O-caffeoyl-D- quinic acid, procyanidin B2 and epicatechin in the peels and trans-5-O-caffeoyl-D-quinic acid, procyanidin B1, catechin and epicatechin in the seeds. Residues from both cultivars exhibited high superoxide radical and hypochlorous acid-scavenging capacity. Phenolic compounds found most frequently in the samples by GC/MS technique were trans-5-O-caffeoyl-D-quinic acid and epicatechin. Peel from the cultivar Fuerte significantly suppressed the production of TNF-? and NO, which are involved in inflammatory processes, and this suppression may be related to the high phenolic content and antioxidant activity observed. Residues of avocado processing can therefore be considered sources of bioactive compounds with high functional potential (AU)