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Received Nov 22, 2017; Revised Feb 2, 2018; Accepted Feb 20, 2018
This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
1. Introduction
Berries are mainly consumed fresh but are also used to manufacture products such as juices and concentrates [1]. The residues generated after separation of peels, seeds (4.4% to 12.2%), and pulp are commonly discarded by the industry but still have flavonoids, colorants, pectins, and organic acids [2–4] that can be used or recovered.
Organic acids and sugars are soluble constituents in berries that are responsible for taste and serve as an index of fruit ripeness; both factors affect consumer acceptability [5]. Previous research has reported that different species of whole berries contain organic acids such as citric, malic, tartaric, fumaric, and shikimic acids in total content ranges of 21.5 to 235 mmol/kg, specifically of 45.1 mmol/kg for the fruticosus species [6]. Published literature about the content of these individual compounds in blackberry (Rubus fruticosus) residues was not found.
Blackberry (Rubus fruticosus) fruits also contain phenolic compounds as anthocyanins, flavonols, chlorogenic acid, and procyanidins, which can have beneficial effects on human health [7]. Phenols are considered compounds with potent antioxidant and free-radical scavenging properties that protect important biomolecules against oxidative damage [8]. Several studies have evaluated these compounds in blackberries (Rubus) of different species and varieties (R. sp. hyb Marion, R. laciniatus Evergreen, R. spp. Tupy, and R. fruticosus) as a whole fruit and in pulp or seeds, including the use of several extraction technologies (supercritical carbon dioxide extraction, ultrasound assisted extraction, pressurized liquid extraction, etc.) to recover phenols, anthocyanins, fatty acids, phytosterols, and tocopherols, compounds responsible for antioxidant activity [9–14]. Fewer studies have been performed on the evaluation of antioxidants in the bagasse or residues generated by the blackberry fruit processing [11, 13, 15]. Phenolic compounds and dietary fiber are generally studied separately, probably because of the differences in their chemical structures, physicochemical and biological properties, and metabolic pathways [16]. However, these are plant food constituents that are associated with many health benefits and have been demonstrated to reduce the risk of developing cancer and some chronic diseases [17, 18]. Dietary...