Anthocyanins Recovered from Agri-Food By-Products Using Innovative Processes: Trends, Challenges, and Perspectives for Their Application in Food Systems

Abstract

Anthocyanins are naturally occurring phytochemicals that have attracted growing interest from consumers and the food industry due to their multiple biological properties and technological applications. Nevertheless, conventional extraction techniques based on thermal technologies can compromise both the recovery and stability of anthocyanins, reducing their global yield and/or limiting their application in food systems. The current review provides an overview of the main innovative processes (e.g., pulsed electric field, microwave, and ultrasound) used to recover anthocyanins from agri-food waste/by-products and the mechanisms involved in anthocyanin extraction and their impacts on the stability of these compounds. Moreover, trends and perspectives of anthocyanins’ applications in food systems, such as antioxidants, natural colorants, preservatives, and active and smart packaging components, are addressed. Challenges behind anthocyanin implementation in food systems are displayed and potential solutions to overcome these drawbacks are proposed.

Anthocyanins in Chronic Diseases: The Power of Purple

“…Anthocyanin molecules are highly unstable and easily degraded by enzymes, light, temperature, pH and oxygen concentration; these factors prove a challenge to the recovery processes [ 6 , 12 ]. Method selection should consider the cost, versatility, method complexity, extractability and preservation of the target compounds [ 12 , 13 ].…”

“…Anthocyanin molecules are highly unstable and easily degraded by enzymes, light, temperature, pH and oxygen concentration; these factors prove a challenge to the recovery processes [ 6 , 12 ]. Method selection should consider the cost, versatility, method complexity, extractability and preservation of the target compounds [ 12 , 13 ]. An example of anthocyanin recovery from blackcurrant pomace is the use of acidified water extraction followed by a solid-phase extraction with sequential liquid–liquid aqueous-organic partitioning to separate monomeric and polymeric anthocyanins as well as flavonoids.…”

“…Increasingly, the food industry is interested in applying mild non-thermal methods of processing in anthocyanin extraction including ultrasound-assisted extraction, pressurised liquid extraction, supercritical fluid extraction, high hydrostatic pressure extraction, pulsed light, pulsed electric field, high-voltage energy discharge extraction, microwave-assisted extraction, enzyme-assisted extraction and instant controlled pressure drop-assisted extraction together with bio-based solvents [ 12 , 15 , 16 , 17 , 18 ].…”

“…Microwave-assisted extraction is another green extraction method that produces a high yield with decreased solvent usage and lower extraction time [ 23 ]. Microwave-assisted extraction improved extraction of anthocyanins from agri-food by-products compared to other traditional extraction technologies or other green extraction methods such as ultrasound-assisted methods [ 12 ]. However, an extraction temperature of more than 60–64 °C, irradiation times of more than 15 min and increased microwave power decreased yields of anthocyanins [ 24 , 25 , 26 ].…”

By-Products Revalorization with Non-Thermal Treatments to Enhance Phytochemical Compounds of Fruit and Vegetables Derived Products: A Review

“…It has been recently concluded that berry by-products from processing steps are a cheap and available source for isolating anthocyanins-rich extracts using non-thermal processing technologies as can be observed in Table 2 . These technologies have been demonstrated to have unique characteristics such as being effective, rapid, low-cost, and eco-friendly [ 106 , 107 ]. It is essential to highlight that the accuracy of the technique depends on not only the conditions or the matrix of the F&V by-products.…”