Obtaining Protein Isolate from Defatted Avocado Pulp (Persea Americana) - Waste from the Olive Oil Production Industry

The research, a pioneer in the use of residual pulp from the extraction of avocado oil, usually discarded, aimed to obtain a protein isolate of high nutritional and technological value, in line with the UN SDGs. Pulps from four avocado varieties (Hass, Geada, Quintal and Margarida) were used before and after defatting, as well as an industrial sample (Fazenda Irarema, Poços de Caldas, MG). The oil extraction was performed by breaking the emulsion in water under slow stirring (76 °C, 64 rpm, 120 min). The defatted pulp was dried in an oven at 50 °C to constant weight, crushed and sieved. To obtain the protein isolate, an alkaline extraction was performed, followed by isoelectric precipitation. The product of these processes was also dried in an oven at 50 °C to constant weight. After extraction, ANOVA and Tukey's Mean Test (α = 0.05) were performed to compare the results by avocado variety. The defatted varieties Hass, Geada and Quintal did not differ in protein isolate content, resulting in the highest average extraction (23.0, 18.0 and 15.8 mg protein isolate/g defatted pulp, respectively); while Margarida had a lower protein isolate content (only 4.6 mg/g). The industrial sample showed a protein isolate content of approximately 1.6 mg/g, a reduced value due to the presence of peel and pit, which increase the carbohydrate and fiber contents, reducing the proportion of protein. Despite this, the value was higher than that found in intact pulps of other tropical fruits, such as passion fruit (≈0.80 mg/g), mangaba (≈0.62 mg/g) and cupuaçu (≈0.54 mg/g)