Modern Extraction and Purification Techniques for Obtaining High Purity Food-Grade Bioactive Compounds and Value-Added Co-Products from Citrus Wastes

Abstract

Citrus contains a range of highly beneficial bioactive compounds, such as polyphenols, carotenoids, and vitamins that show antimicrobial and antioxidant properties and help in building the body’s immune system. On consumption or processing, approximately 50% of the fruit remains as inedible waste, which includes peels, seeds, pulp, and segment residues. This waste still consists of substantial quantities of bioactive compounds that cause environmental pollution and are harmful to the ecosystem because of their high biological oxygen demand. In recent years, citrus cultivation and the production of processed foods have become a major agricultural industry. In addition to being a substantial source of economy, it is an ideal and sustainable and renewable resource for obtaining bioactive compounds and co-products for food and pharmaceutical industries. In the present article, the various methods of extraction, conventional and modern, as well as separation and isolation of individual bioactive compounds from the extraction mixture and their determination have been reviewed. This article presents both aspects of extraction methods, i.e., on a small laboratory scale and on an industrial mass scale. These methods and techniques have been extensively and critically reviewed with anticipated future perspectives towards the maximum utilization of the citrus waste.

Citrus Essential Oils (CEOs) and Their Applications in Food: An Overview

“…As a diverse tropical fruit, citrus combines species like Citrus sinensis (Orange), Citrus reticulata (Mandarin), Citrus aurantifolia (Limes), Citrus limon (Lemon), Citrus paradisi (Grapefruit), Citrus bergamia (Bergamot), Citrus junos (Yuzu), and Citrus japonica (Kumquat) [1,2]. The Citrus species originated from the Himalayan foothills of Northern India, Northern Myanmar, Southern China, and Southeast Asia [3,4]. Later, these fruits spread to the other parts of the world, becoming the world's highest value fruit crops [5].…”

“…The basic purification methods include column chromatography, High-Speed Counter-Current Chromatography (HSCC), High-Performance Liquid Chromatography (HPLC), and some solvent combinations, such as hexane: n-butanol, ethyl acetate: hexane, butanol: water, and chloroform: methanol, etc. [4]. After purification, the EOs present in the extract can be detected and quantified by several methods, such as Gas Chromatography-Mass Spectrometry (GC-MS), Gas Chromatography-Flame Ionization Detector (GC-FID), Nuclear Magnetic Resonance (NMR), Attenuated Total Reflection Fourier-Transform Infrared Spectroscopy (ATR-FTIR), Ultra-High Performance Liquid Chromatography Time-of-Flight Mass Spectrometry (UHPLC-TOF-MS), etc., as shown in Table 1.…”

Methodological review: Socio-cultural analysis criteria for BIM modeling and material passport tracking of agriwaste as a building construction raw material

“…119 Bioprotocols are needed to ensure the safety and security of biotechnology processing that will be needed for industrial scale biosynthesis of agriwaste biocomposites such as PHA and PLA. 120,121 Open Material Transfer Agreement (OpenMTA) DNA sequencing can be linked to supply chain tracking processes. [122][123][124][125] Additional research is needed on the integration of OpenMTA, techno-economic assessments, and bioprotocols with supply chain tracking for Material Banks and Material Passports.…”

Optimisation of Sequential Microwave-Assisted Extraction of Essential Oil and Pigment from Lemon Peels Waste

“…Citrus peels contain two types of natural pigments with differing polarities, such as lipid-soluble carotenoids and water-soluble yellow pigments, which can be a valuable natural source of colourants to replace synthetic ones, providing additional colouring to food products [ 10 , 11 ]. The lemon flavedo contains carotenoids, either xanthophylls (oxygen-containing carotenoids) or carotenes (oxygen-free carotenoids) [ 12 ].…”