Conventional and emerging techniques for extraction of bioactive compounds from fruit waste

Abstract

Fruit residues (peel, seed, and pulp residues) have in their composition several compounds such as polyphenols, carotenoids, fibres, and lipids which, due to their functional properties, these compounds make them potential sources of natural additives. The great technological challenge is to use the most suitable techniques for extracting these compounds. In this paper, definitions, advantages, and disadvantages of conventional (maceration, soxhlet extraction, hydrodistillation) and emerging (Ultrasonic-Assisted Extraction (UAE), Microwave-Assisted Extraction (MAE), Supercritical Fluid Extraction (SFE), Pressurized Liquid Extraction (PLE), and Pulsed Electric Field (PEF)) techniques for the extraction of bioactive compounds from fruit residues will be shown. Some emerging techniques are based on non-thermal process, reduced use of energy and the implementation of no toxic solvents, being considered “green” or “clean” technologies. These ones are particularly interesting to extract heat-labile compounds. In addition, enzyme-assisted extraction and extractions through fermentation processes (submerged or solid-state fermentation) will be highlighted as alternative to promote the release of compounds from fruit residues not extracted by other techniques. These extractions techniques can enhance the content of bioactive compounds by increased their concentrations, as well as new compounds can be formed after these processes. It has been proven that the emerging techniques and fermentative processes, as alternative to conventional methods, are promising to extract bioactive compounds from fruit residues, since that these techniques improved extraction yields, reduced processing times, and reduced environmental damage are achieved.

Keywords:
Fruit residue; Solvents; Extraction methods; Fermentation; Enzymes; Phenolic compounds

HIGHLIGHTS

Bioactive compounds from fruit residues are commonly extracted by conventional methods

“Green” extraction techniques have been highlighted as alternative to extract compounds from fruit residues

Fermentation processes have increased the polyphenolic content extracted from residues

Enzyme assisted extraction promotes the release of bound compounds from matrix solid