## 2 Discussion
The extraction of these biologically active compounds can be performed using solvents of different polarities--for example, water, ethanol, methanol, or acetone. In this work, the authors extracted these natural pigments by using acidified and nonacidified ethanol, following the reports previously published [101; 102]. The analysis of phenolic acids was performed by HPLC equipped with a PDA using a reverse-phase column. Meanwhile, anthocyanins were analyzed by HPLC with a PDA and identified with HPLC coupled with time-of-flight (TOF)-MS. The analysis and quantification of the maize samples show the presence of C3G as the main anthocyanin. Nevertheless, the presence of two isomers of cyanidin di-succinyl-glucoside (CDSG) (I and II), three isomers of cyanidin-3-(6\({}^{\prime\prime}\)malonyl-glucoside) (C3(6 MG)) (I, II, and III), cyanidin-3-succinyl-glucoside (C3 SG), PG3G, and pelargonidin-3-(6\({}^{\prime\prime}\)-malonyl-glucoside) (P3(6 MG)). It is important to note the differences observed during the extraction process related to the use of acidified or nonacidified ethanol. These differences imply that some anthocyanins can be isolated and quantified when one extraction method is used but not with the other and vice versa. The above serves to highlight the importance of the method of extraction of biologically active compounds from vegetables. The authors concluded that the extraction with nonacidic ethanol was better than that with acid-ethanol because it contained more anthocyanins. Another study was conducted to analyze the anthocyanins present in industrial preparations of pigmented maize [103]. This study aimed to analyze the anthocyanins composition of a commercial extract from purple maize, obtained from maceration with nonacidified ethanol. The analysis was developed using HPLC with a PDA detector (C18 column) coupled with a mass spectrometer with ESI interface. The findings show a different pattern of anthocyanins when compared to those reports from [86,100]. For example, C3G is the most abundant anthocyanin, but it is also revealed the presence of PG3G, P3G, C3(6 MG), PG3(6 MG), cyanidin-3-(6\"-ethyl malonyl-glucoside) (C3(6 EMG)), pelargonidin 3-(6\"-ethyl malonyl-glucoside) (PG3(6 EMG)), and peonidin 3-(6\"-ethyl malonyl-glucose) (P3(6 EMG)). From this list, the only PG3G were identified and quantified in the three studies, and PG3(6 MG) in two of them [100,103]. Similar results to those obtained for [PERSON] et al. [103] were previously reported by [PERSON] et al. [104] from maize cultivated in England, with the presence of C3G, C3(6 MG), cyanidin 3-(3\",6\"-dimalonylglucoside) (C3(3,6 DMG)), P3G, P3(6 MG), and peonidin 3-(dimalonylglucose) (P3(DMG)). Interestingly, in this work is reported the presence of the same anthocyanins but in different proportions from samples of flowers of reed canary grass (_Phalaris arundinacea_), cultivated in Norway. For the above, it is evident that the use of spectrophotometric and spectrometric instrumentation permits the isolation and quantification of anthocyanins, allowing the identification of these bioactive compounds present in trace quantities. This can be applied in the fingerprinting of cultivars to determine their origin, particularly because, as reported elsewhere [105], the plant variety, geographical and climatic conditions, fertilization, soil, cultivation practices, and fruits' degrees of ripeness influence the presence of phenolic compound contents. The quantification, separation, identification, and following of the extract stability by measuring the color and the antioxidant properties of anthocyanins are required activities that carried out with the support of spectroscopic and spectrometric applications. We have also been working on the modification of the previously known phenolic compounds to enhance their chemical stability through biomimetics. Using spectroscopic techniques to identify and quantify these novel compounds is transcendental.