Polyphenol Extraction by Different Techniques for Valorisation of Non-Compliant Portuguese Sweet Cherries towards a Novel Antioxidant Extract

Abstract

<jats:p>Currently, there is special interest in the recovery of polyphenols from non-compliant fruits that have no market value; efforts to find value-added solutions for these food areas are a key option for a sustainable bio-economy. Saco cherries are a traditional Portuguese cherry variety, and although they are a nutritionally important food, rich in powerful dietary polyphenols, significant amounts of these cherries are not sold due to their small size. In this context, this work aimed to select the best method to produce novel antioxidant polyphenol-rich extracts from low calibre and non-compliant Saco cherries. Based on the results, microwaves-assisted extraction (MAE) allowed us to obtain a polyphenol-rich extract with a high antioxidant capacity (50.46 ± 1.58 mg Trolox equivalent (TE)/g dry extract (DE) by oxygen radical absorbance capacity (ORAC), 10.88 ± 0.38 mg ascorbic acid equivalent (AA)/g DE by 2-azinobis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS), and 9.58 ± 0.42 mg TE/g DE by 2,2-diphenyl-1-picrylhydrazyl (DPPH)) and a high content of polyphenols, namely, hydroxycinnamic acids (neochlorogenic and p-coumaric acids) and anthocyanins (cyanidin-3-rutinoside and cyanidin-3-glucoside), compared with those of conventional extractions with low and high temperature and ultrasound-assisted extraction. The antioxidant extract produced from MAE could be a new alternative for the valorisation of non-compliant cherries since these extracts proved to be a functional ingredient due to the high content of antioxidants, which are linked to the prevention of diseases.</jats:p>

Impact of Extraction Process in Non-Compliant ‘Bravo de Esmolfe’ Apples towards the Development of Natural Antioxidant Extracts

“…The ORAC values showed a high positive correlation with the previous values of TPC (R 2 = 0.9886), and the ORAC values were much higher than the values of DPPH and ABTS. This kind of differences in values determined by the different methods was previously reported in our work that aims to develop natural antioxidant extracts from cherries [15] and probably arise from the different chemical structures of used radicals and the distinct mechanisms involved during each methodology. In ABTS and DPPH method, it was evaluated the Single-electron transfer (SET) capacity, and in the ORAC assay the hydrogen atom transfer (HAT) capacity [49].…”

“…The extraction is an essential step in the production of antioxidant extracts for food ingredients formulation since it is imperative to obtain higher concentration of target compounds while minimizing the concentration of the other compounds that could interfere with the extract quality and stability, which make them undesired in this extract, despite their nutritional value. Moreover, the extraction should be easy, low-cost, harmless, reproducible and suitable for industrial scale-up [15]. Green chemistry-based extraction methods such as microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE), has been widely explored for the recovery of polyphenols from different by-products once these methodologies demonstrate higher yield in less time while reducing solvent and energy consumption [16].…”

“…Until now, to the best of our knowledge, there are no studies applying MAE and UAE to non-compliant BE apples in order to develop natural antioxidant extracts. Notwithstanding, our research group already carried out similar works with non-compliant cherry to produce antioxidant extracts [15]. The main purpose of this research work was compared two green extraction techniques (MAE and UAE) with CE (with low and high temperatures) to observe the best technique to produce a natural antioxidant extract rich in polyphenols from non-compliant BE apple for further food applications.…”

“…The solvent used, a mixture of ethanol and water (50:50, v:v), was selected based on results obtained in previous studies with different mixture percentage of ethanol in the mixture. The solvent ethanol and water (50:50, v:v) is considered (i) food grade, (ii) environmentally friendly, (iii) could be reused in the process, and finally (iv) this mixture is one of the most common mixtures of solvents used to produce extracts rich in phenolic compounds [15]. The four different antioxidant extracts developed were evaluated regarding their phenolic compounds composition and antioxidant capacity using chemical in vitro assays.…”

Antioxidant Properties of Fruit and Vegetable Whey Beverages and Fruit and Vegetable Mousses

“…Both mousses contain apple and beetroot rich in phenolic compounds [ 21 ]. In addition, R2 mousse contains pomegranate beverage and goji berries, and R3 mousse the 9% addition of cherries, considered a very good source of polyphenolic compounds [ 22 ]. Moreover, the R3 mousse had the highest content of compounds from the flavonoid group due to its varied composition.…”