Supercritical fluids and fluid mixtures to obtain high-value compounds from Capsicum peppers

Abstract

Peppers of the Capsicum genus have a rich nutritional composition and are widely consumed worldwide. Thus, they find numerous applications in the food, pharmaceutical and cosmetic industries. One commercial application is oleoresin production, a nonpolar fraction rich in bioactive compounds, including capsaicinoids and carotenoids. Among the technologies for pepper processing, special attention is given to supercritical fluid technologies, such as supercritical fluid extraction (SFE) with pure solvents and CO₂ plus modifiers, and SFE assisted by ultrasound. Supercritical fluid-based processes present advantages over the classical extraction techniques like using less solvents, short extraction times, specificity and scalability. In this review, we present a brief overview of the nutritional aspects of peppers, followed by studies that apply supercritical fluid technologies to produce extracts and concentrate bioactives, besides oleoresin encapsulation. Furthermore, we present related phase equilibrium, cost estimation, and the gaps and needs for the full use of peppers from a sustainable perspective.

Keywords: Capsaicin (PubChem CID1548943); Capsaicinoids; Capsanthin (PubChem CID5281228); Capsiate (PubChem CID9839519); Capsorubin (PubChem CID5281229); Carotenoids; Dihydrocapsaicin (PubChem CID107982); Dihydrocapsiate (PubChem CID9873754); Homocapsaicin (PubChem CID6442566); Homodihydrocapsaicin (PubChem CID3084336); Hot peppers; Lutein (PubChem CID5281243); Luteolin 8-C-glucoside (PubChem CID90658326); Nordihydrocapsaicin (PubChem CID168836); Pressurized liquid extraction; Quercetin-3-O-rhamnoside-7-O-glucoside (PubChem CID6325870); Supercritical fluid extraction; Violaxanthin (PubChem CID448438); Zeaxanthin (PubChem CID5280899); β-Carotene (PubChem CID5280489); β-Cryptoxantin (PubChem CID5281235).

Fig. 1

Chemical structure of main bioactive compounds found in Capsicum ssp. Peppers.

Fig. 2

Schematic illustration of Capsicum and derivatives compounds and their benefits on human health.

Fig. 3

Example of an extraction unit for single SFE and PLE process, and sequential extraction (SFE + PLE); highlighted gray line () indicates the components used for the SFE and highlighted blue line () indicates the components used for the PLE; V-1 to V-6: block valves; V-7: micrometer valve; VS: safety valve; C: compressor; F: air filter; FC: CO₂ filter; BR: cooling bath; BP: CO₂ pump; BA: heating bath; CE: jacketed extraction column; R: solvent reservoir; B: HPLC pump; I-1 and I-2: pressure indicators; I-3: temperature indicators; IC-1 and IC-2: temperature controller; F: flow meter; R: flow totalizer. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

Fig. 4

Basic paths of fresh pepper/residue processing and the subsequent bioactive compounds recovery through high-pressure extraction technologies.