High Biological Value Compounds Extraction from Citrus Waste with Non-Conventional Methods

Abstract

Citrus fruits are extensively grown and much consumed around the world. Eighteen percent of total citrus cultivars are destined for industrial processes, and as a consequence, large amounts of waste are generated. Citrus waste is a potential source of high biological value compounds, which can be used in the food, pharmaceutical, and cosmetic industries but whose final disposal may pose a problem due to economic and environmental factors. At the same time, the emerging need to reduce the environmental impact of citrus waste and its responsible management has increased. For these reasons, the study of the use of non-conventional methods to extract high biological value compounds such as carotenoids, polyphenols, essential oils, and pectins from this type of waste has become more urgent in recent years. In this review, the effectiveness of technologies such as ultrasound assisted extraction, microwave assisted extraction, supercritical fluid extraction, pressurized water extraction, pulsed electric field, high-voltage electric discharges, and high hydrostatic pressures is described and assessed. A wide range of information concerning the principal non-conventional methods employed to obtain high-biological-value compounds from citrus waste as well as the most influencing factors about each technology are considered.

Optimization of Vacuum-Microwave-Assisted Extraction of Natural Polyphenols and Flavonoids from Raw Solid Waste of the Orange Juice Producing Industry at Industrial Scale

“…A new trend for the extraction of polyphenols and flavonoids from solid pomace from the orange juice industry is the use of green deep eutectic solvents as a replacement of the hazardous and explosive organic solvents. Information about this novel trend of eco green extraction of orange pomace is given in a series of literature references [ 24 , 25 , 26 ].…”

Green Extraction Techniques for Obtaining Bioactive Compounds from Mandarin Peel (Citrus unshiu var. Kuno): Phytochemical Analysis and Process Optimization

“…The major concern of food-processing industry is efficient waste management and adequate waste disposal [ 1 ]. Citrus fruits, which belong to the Rutaceae family, play an important role in food-processing industry and agro-industrial sector, and they were considered as one of the most commonly cultivated and consumed fruits all over the world [ 2 , 3 ]. The main industrial product of citrus processing is undoubtely juice, including also other products such as jams, marmelades, flavouring agents, candied peel and essential oils [ 4 , 5 , 6 ].…”

Green and Non‐conventional Extraction of Bioactive Compounds from Olive Leaves: Screening of Novel Natural Deep Eutectic Solvents and Investigation of Process Parameters

“…Non-conventional procedures aim to enhance extraction yield, decrease the cost and enhance the selectivity of the extraction. These procedures include the use of ultrasound, microwave, supercritical fluid extraction, pressurized liquid extraction, pulsed electric fields and high voltage electrical discharges [18][19][20][21][22][23]. Among these non-conventional methods, ultrasound assisted extraction is considered to be one of the most interesting techniques because it is simple, efficient and also cheap [24].…”

“…Beyond these, ultrasound creates interfacial instabilities and efficient compressions and expansions influencing external and internal mass transfers. Additionally, this principal non-conventional method is regarded as a green extraction method due to the reduction in energy consumption and ensuring safety as well as sustainability [23,26,27]. Ultrasound-assisted extraction is known to improve the efficiency of the green solvents, enhance both the extraction yield and rate, additionally known to be safe for the heat sensitive components [27].…”