Deep Eutectic Solvents and Nonconventional Technologies for Blueberry-Peel Extraction: Kinetics, Anthocyanin Stability, and Antiproliferative Activity

Abstract

Interest in bioactive phytochemicals and sustainable processes is the driving force behind this study on two novel green extraction methods for the recovery of anthocyanins from the residues of blueberry processing. Five natural deep eutectic solvents (NADES) have been tested for anthocyanin extraction. Acidified hydroalcoholic solutions were used as benchmarks and the shelf life of eutectic systems was monitored. The most promising NADES was tested in microwave (MAE)- and ultrasound-assisted extractions (UAEs), and Peleg’s kinetic model was used. Both the enabling technologies provided performance that was superior to that of conventional extraction. MAE and UAE yielded up to 25.83 and 21.18 mg/gmatrix of total anthocyanin content, respectively, after 15 and 30 min. Moreover, a preliminary test for extract concentration and NADES recycling was performed using resin adsorption. Finally, the antiproliferative activity of the extracts was determined by a CellTiter 96® AQueous One Solution Cell Proliferation Assay, the so-called MTS assay, on human tumour HeLa cells and human skin HaCaT cells. Nonconventional extracts exhibited strong antiproliferative activity that was much greater than that of their conventionally extracted analogues. Flow cytometry was used to evaluate cell-death type, and apoptosis was found to be the primary cause of tumour cell death. The presented study demonstrates that the implementation of enabling extraction technologies and green solvents can produce an antiproliferative agent from a food industry byproduct.

Ultrasound-Assisted Extraction of Anthocyanins Using Natural Deep Eutectic Solvents and Their Incorporation in Edible Films

“…This method is often preferred for the extraction of heat-sensitive compounds such as anthocyanins [ 12 , 13 ]. The principal advantages of NADES are that their interaction confer excellent physical and chemical properties, such as low volatility, nonflammability, and adjustable viscosity [ 10 , 14 , 15 ], giving NADES solubilizing behavior that is different from other conventional solvents and has been used more recently in combination with ultrasound energy in order to increase extraction yield of natural products [ 16 , 17 , 18 , 19 , 20 ]. In particular, it has been seen that the use of NADES composed of combinations of quaternary ammonium salt-alcohol, quaternary ammonium salt-carboxylic acid and carboxylic acid-sugar have been used to extract anthocyanins from plant matrices.…”

Effect of Curcumin Addition on the Properties of Biodegradable Pectin/Chitosan Films

“…A deep eutectic solvent (DES) is a liquid formed by the interaction of two or more components through strong hydrogen bonds, in which the melting temperature is much lower than that of any of the single components [ 12 , 13 ]. DES is not only cheap, but also has high solubility, low toxicity, low volatility, and good bio-degradability, which has been widely used in bioactive extraction [ 14 ], reaction media, melt processing [ 15 ], and organic synthesis [ 16 ]. In this study, DES was used to dissolve chitosan instead of acid reagents (used in some traditional methods) and had the additional advantage of eliminating the bad odor.…”

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

“…Although the MW intensification generally enhances the anthocyanin extraction, a decreased anthocyanin recovery can occur depending on the intensity of the process parameters. Grillo et al [ 121 ] reported that anthocyanin extraction from blueberry peel enhances up to a certain point (up to 62.7% higher than conventional extraction) as extraction temperature (up to 60 °C) and irradiation time (up to 15 min) increases and decreases afterward. Similar behavior was observed by Backes et al [ 123 ] for fig peel anthocyanins, where the extraction yields enhanced (38% and 16.73% compared to the US and conventional thermal extractions, respectively) as the extraction temperature was increased (up to 64.21 °C), but begins to decrease with the rise of extraction temperature (>64.21 °C) and irradiation time (>5 min).…”

“…Doulabi et al [ 40 ] and Backes et al [ 136 ] noticed that the longer the irradiation time, the lower the anthocyanin recovery from eggplant peel and fig peel, respectively. Likewise, excessively long irradiation times beyond optimal point can also result in a reduction in the anthocyanin extraction from grape pomace [ 124 , 125 ], blueberry peel [ 121 ], blackcurrant bagasse [ 51 ], black rice bran [ 45 ], black carrot pomace [ 39 ], and corn husk [ 43 ].…”