phd juliane

Sequential extraction of bioactive compounds from industrial by-products of passion fruit (Passiflora edulis sp.) using pressurized fluids

Author: Juliane Viganó (2016)

Abstract: This work proposes sequential processes to obtain bioactive extract fractions from the

industrial waste of yellow passion fruit (Passiflora edulis sp.). The motivation of this theme is

based on: i) to use and to add value to wastes produced during the passion fruit processing;

and ii) the extraction of bioactive compounds from plant matrices using clean techniques.

Bagasse and rinds were the used raw materials. The bagasse, which was previously dried and

ground, was submitted to supercritical fluid extraction (SFE). Pressure (17, 26 and 35 MPa)

and temperature (40, 50 e 60 ºC) were the evaluated variables, and carbon dioxide (CO2) was

used as solvent. This step of SFE showed that different process conditions allow obtaining

extracts with different chemical compositions. The sequence of extractions was performed

and three extract fractions concentrated in tocols (60 °C and 17 MPa), polyunsaturated fatty

acids (50 °C and 17 MPa) and carotenoids (60 °C and 26 MPa) were obtained. Extraction

with pressurized liquids (PLE), at 10 MPa, was applied to the raw material that had been

previously submitted to SFE. Mixtures of ethanol and water (50, 75 and 100%, m/m) and

temperature (50, 60 and 70 °C) were the evaluated variables. The condition that presented the

best results, in terms of global yield, total phenolic content and piceatannol content, was

70 °C and 75% ethanol (m/m). The previous SFE steps played an important role in PLE, since

they allowed recovering a high yield of target compounds. The bagasse extracts, obtained by

SFE, were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and oxygen radical

absorbance capacity (ORAC) assays, and the rind extracts, obtained by PLE, were evaluated

by DPPH, ORAC and ferric reducing ability of plasma (FRAP). All the extracts presented

antioxidant capacity. High and positive correlations were obtained between antioxidant

capacity and total tocol content, total phenolic content, and piceatannol content. The rind,

which was previously dried and ground, was submitted to SFE. However, this process did not

produce extract, and therefore only PLE was applied. Temperature (30, 45 and 60 °C) and

ethanol percentage in water (70, 85 and 100%, v/v) were the evaluated variables. The results

showed 60 °C and 70% (v/v) as the best condition to obtain phenolic compounds, among

which, isoorientin, vicenin, orientin, isovitexin and vitexin were identified and quantified. The

antioxidant capacity was measured by DPPH, FRAP, and ORAC. The content of phenolic

compounds presented high and positive correlation with antioxidant capacity. For both raw

materials, bagasse and rind, extractions at high pressure were compared with low-pressure

techniques, as Soxhlet and maceration, and SFE and PLE presented better performance for the

evaluated responses. The sequential extraction process applied to the bagasse, and PLE

applied to the rinds were submitted to economic analyses using the SuperPro Designer 9.0®

software. Producing extracts fractions from bagasse and extract from rind showed to be

economically applicable, especially when the extracts are obtained in large scale (extractor

capacity higher than 50 L) and commercialized at average price of US$ 230.00/kg bagasse

extract and at US$ 125.00/kg rind extract. The lowest costs of manufacturing were obtained

for the biggest simulated production scale, i.e., for plants composed by two 500 L extractors.

From the obtained results, it was concluded that sequential processes based on SFE and PLE

are viable to obtain extracts from vegetal matrixes, containing compounds with different

polarities. Therefore, sequential extraction processes appear as an option to achieve the whole

use of raw materials. The bioactive extracts from passion fruit by-products obtained by the

techniques indicated in this work are alternative products for food, pharmaceutical, and

cosmetic industries.