Avocado-Derived Biomass: Chemical Composition and Antioxidant Potential

Abstract

Avocado has become fashionable due to its great organoleptic and nutritional properties. It is consumed as a fresh product and it is also processed to obtain salad oil and guacamole. In all cases, the only usable portion is the pulp. Therefore, to be a more sustainable and profitable agribusiness, it is important to recognize which compounds from the peel and the stone waste can be converted into valuable bio-products. Therefore, their chemical composition was determined according to the National Renewable Energy Laboratory, the total phenolic content by the Folin-Ciocalteu method and the antioxidant properties by the FRAP and TEAC assays. The main components of the peel and stone were acid-insoluble lignin (35.0% and 15.3%, respectively), polymeric sugars (23.6% and 43.9%, respectively), and the aqueous extractives (15.5% and 16.9%, respectively). Both biomasses contain lipids and protein, but a minor proportion (<6%). The valorization of lignin and sugars is of interest given the high content; stones are a rich source of glucose (93.2% of the polymeric fraction), which could be used to obtain biofuels or derivatives of interest. The extractive fraction of the peel contained the highest number of phenolic compounds (4.7 g/100 g biomass), mainly concentrated in the aqueous fraction (i.e., 87%) compared to the ethanol one, which was subsequently extracted. It correlated with major antioxidant activity and, therefore, the peel can be applied to obtain antioxidants and water can be used as an environmentally friendly extraction solvent.

Agronomic Potential of Avocado-Seed Biochar in Comparison with Other Locally Available Biochar Types: A First-Hand Report from Ethiopia

“…Tis is in line with the study reported by Nguyen et al [40] where rice husk showed a higher biochar yield (35%) compared with bamboo biochar yield of 30%, which could be attributed to feedstock variation. Te higher biochar yield of ASB-450 °C than ASB-550 °C in this study is mainly attributed to the lower pyrolysis temperature and the higher lignin content [17,46] contained in its feedstock. Lignin content varies among diferent feedstock types, which afects the yield of the produced biochars pyrolyzed with similar temperatures [42,47,48].…”

“…Moreover, biochar from plant sources, particularly wood biochar has been widely characterized for application of agronomic purposes than biochar from animal sources and sewage sludge, because of the risk of contamination of heavy metals and other pollutants [9]. In addition, most biochar characterization studies have been carried out for agronomic purposes [10][11][12] including reclamation of degraded soils and enhance carbon sequestration to mitigate climate change [13], for the generation of bio-oil and energy [14], and for removing pollutants [15][16][17]. However, the characterization studies of avocado seed biochar have not been conducted to assess its impact on soil properties and crop production.…”

Extraction of Avocado Peel Oil Using a Soxhlet Extractor and Investigation of Its Physicochemical Properties

“…According to the study by García-Vargas et al (2020), the particle size of the sample was standardized at 500 µm and dried by air [14]. Finally, the powder was kept in a plastic bag until it could be analyzed further.…”

Degradation activity of fungal communities on avocado peel (Persea americana Mill.) in a solid-state process: mycobiota successions and trophic guild shifts

“…The resulting powder was sieved through a 40-gauge mesh and autoclaved at 121 °C (1.05 kg•cm −2 ) for 20 min. Subsequently, it was dried aseptically in a natural convection oven at a constant temperature of 70 °C for 72 h. The resulting avocado flour composed of approximately [acid-insoluble lignin 35.0%; polymeric sugars 23.6%; aqueous extractives 15.5%; and lipids and protein < 6% (García-Vargas et al 2020)] was used as the sole external substrate.…”