Extração e processamento de folhas de Pereskia aculeata Miller empregando tecnologia verde

Abstract

Pereskia aculeata Miller, popularly known as ora-pro-nóbis (OPN), is part of Cactaceae family, its leaf is used to obtain extracts and there are reports of its anti-inflammatory potential. In addition, the leaves have application protein content, which makes them more favorable as a vegetable protein source. Therefore, this work has two research purposes, the first objective is to perform the lipid extraction of OPN leaves by the techniques of ultrasound-assisted extraction (UAE) and supercritical extraction (SCE) with CO2, evaluating the yield, content of phenolic compounds, antioxidant activity, antimicrobial activity, and chemical composition by GC-MS. The influence of power, sample to solvent ratio (SSR), and temperature on extraction yield, total phenolic content, and antioxidant activity was evaluated using experimental design. The supercritical extraction with CO2 was carried out using a 2² experimental design, the variables analyzed were temperature and pressure. It was also performed an experiment with the addition of cosolvent (ethanol) at the optimal point. The second aim of this study is to obtain protein hydrolysates from the leaves of ora-pro-nóbis. For that, two proteolytic enzymes, animal source based, were evaluated in the hydrolysis, pepsin and pancreatin, which were used alone and in combination. The experiments were carried out at temperatures of 37 and 45ºC, 100 rpm, for 15 and 24 h, without and with pretreatment with ultrasound-assisted extraction. As for the results, the ultrasound-assisted extraction showed a maximum yield of 5.57%, in the experimental condition of 70% power, 60ºC and 1:20 SSR. This experimental condition was also the optimized condition obtained by the experimental design. In this condition, high levels of antioxidant activity and phenolic compounds were obtained, as well as antimicrobial activity for the bacterium Staphylococcus aureus. Regarding the chemical composition of OPN extracts, the compounds squalene, α-tocopherol and octacosanol were identified, this second one being reported for the first time in OPN extracts. As for the supercritical extraction with CO2, the highest yield was 1.39% at 325 bar and 60ºC, a condition that is applied in the optimization of the experimental design. Adding cosolvent in the SCE process, 20% ethanol, the yield increased to 2.38%, an increase of 70% in relation to the same condition without the addition of cosolvent. Antioxidant activity and phenolic compounds by the supercritical extraction technique was lower when compared to ultrasound-assisted extraction. The chemical composition extract obtained by ESC showed a high content of phytol, in addition to the presence of squalene and octacosanol. Regarding the protein enzymatic hydrolysis assays, the highest degree of hydrolysis (DH) was 8,54% using the pepsin enzyme, a promising result for a hydrolyzed plant source. This test was carried out without the application of ultrasound pre-treatment of the leaves. Based on this thesis, it can be concluded that the results of this research are promising and allow us to glimpse commercial applications, both for extracts and protein hydrolysate, whether in the pharmaceutical, food, or cosmetics industry.