Recovery of Phytochemicals via Electromagnetic Irradiation (Microwave-Assisted-Extraction): Betalain and Phenolic Compounds in Perspective

Abstract

Food colorants processed via agro-industrial wastes are in demand as food waste management becomes vital not only for its health benefits but also for cost reduction through waste valorization. Huge efforts have been made to recover valuable components from food wastes and applied in various fields to prove their versatility rather than for feed ruminant usage only. Betalains and phenolics, antioxidant-rich compounds responsible for host color and so commonly used as natural colorants in food and cosmetic industries, are copiously present in several kinds of fruits and vegetables as well as their wastes. Technological innovation has brought extensive convenient ways of bioactive compounds extraction with many advantages like less use of solvents and energy in a short period of processing time in comparison with the classical solid–liquid extraction methods. Emerging technologies, particularly microwave irradiation, have been amenable to electromagnetic technology for decades. Practically, they have been deployed for functional and supplement food production. In this review, the feasibility of dielectric heating (microwave irradiation) in the extraction of betalain and phenolic compounds mostly from fruit and vegetable wastes was discussed.

Innovative Technologies for Extraction and Microencapsulation of Bioactives from Plant-Based Food Waste and Their Applications in Functional Food Development

“…These extracts were incorporated in apple juice and 10% extract addition was found to be acceptable with good sensory properties. PEF and MAE technologies have been used for the extraction of bioactives however, the development of functional food using PEF and MAE continuous extraction technology is still under research [ 281 , 282 ]. Functional food product development using SCFE and PLE methods is also limited to date [ 283 ].…”

Betalains, total polyphenols, and antioxidant contents in red beetroot peel (Cylindra type)

“…Predominant sources of nitrogen containing betalain compounds are red colored vegetables such as opuntia, dragon fruit, swiss chard, pitaya and red beetroot (Akbar Hussain et al, 2018). Beetroot standing first in the list of interest by consumers is regarded as a rich antioxidant vegetable, accompanied with some other bioactive compounds such as betalains, ascorbic acid, carotenoids, phenolic acids, and flavonoids (Zin et al, 2020).…”

“…Betalains are the main compounds associated with the displayed red color of flowers, fruits and other plant tissues offering two color patterns which are yellow betaxanthin and red-violet betacyanin (Zin et al, 2020). Betacyanin named as betanin contains phenolic and cyclic amine groups which strongly exhibits radical scavenging properties is chiefly applied in food industries (Anna et al, 2006).…”

“…Herein, water, methanol-water, and ethanol-water are commonly used solvents in different ratios. Since betalains are sensitive to process conditions, extraction of betalains can be upgraded by adjusting pH (acidification) and processing temperature (Zin et al, 2020). Free sugar content in the matrix can be reduced via fermentation, thereby consequently raising the quantity of betalains (Delgado-Vargas et al, 2010).…”

Characterization of Cylindra Beetroot Wastes Volarized With Green Solvent by Thermal Emerging Technology (Microwave Irradiation)

“…In the Caryophyllales plant group, Amaranthaceae and Cactaceae species are the well-known sources for bio-extracts and rich in betalains and phenolics [10]. Beetroot (Beta vulgaris ssp.…”