Extraction of Anthocyanins and Total Phenolic Compounds from Açai (Euterpe oleracea Mart.) Using an Experimental Design Methodology. Part 1: Pressurized Liquid Extraction

Abstract

Currently, açai is one of the most important fruits present in the world. Several studies have demonstrated its high content in phenolic compounds and anthocyanins. Both of them are responsible of interesting properties of the fruit such as anti-inflammatory, antioxidant or anticancer. In the present study, two optimized pressurized liquid extraction (PLE) methods have been developed for the extraction of anthocyanins and total phenolic compounds from açai. A full factorial design (Box–Behnken design) with six variables (solvent composition (25–75% methanol-in-water), temperature (50–100 °C), pressure (100–200 atm), purge time (30–90 s), pH (2–7) and flushing (50–150%)) were employed. The percentage of methanol in the extraction solvent was proven to be the most significant variable for the extraction of anthocyanins. In the case of total phenolic compounds, the extraction temperature was the most influential variable. The developed methods showed high precision, with relative standard deviations (RSD) of less than 5%. The applicability of the methods was successfully evaluated in real samples. In conclusion, two rapid and reliable PLE extraction methods to be used for laboratories and industries to determine anthocyanins and total phenolic compounds in açai and its derived products were developed in this work.

Anthocyanins: A Comprehensive Review of Their Chemical Properties and Health Effects on Cardiovascular and Neurodegenerative Diseases

“…Other good sources of anthocyanins include purple corn, cherries, plums, pomegranate, eggplant, wine, grapes, and red/purple vegetables such as black carrots, red cabbage and purple cauliflower which may contain from a few milligrams up to 200–300 mg/100 g of product [ 72 , 73 ]. More recently, anthocyanins have been identified in numerous berries whose production and consumption is steadily increasing, such as maqui [ 74 , 75 ], myrtle [ 76 , 77 ], and açai [ 78 , 79 , 80 ].…”

Extraction of Anthocyanins and Total Phenolic Compounds from Açai (Euterpe oleracea Mart.) Using an Experimental Design Methodology. Part 2: Ultrasound-Assisted Extraction

“…The identification of the anthocyanins was performed by UHPLC-QToF-MS as described in our previous article [54]. Briefly, water (2% formic acid) and methanol were used as solvent A and solvent B, respectively.…”

“…Lately, UHPLC is displacing HPLC chromatography, as the chromatographic separations are achieved with greater sensitivity and in shorter analysis times [20,35,38]. The analysis of anthocyanins was performed by UHPLC-UV-vis as described in our previous article [54].…”

“…The p-value obtained was 0.803 (above 0.05), and proved a normal distribution of the residuals. The detection limit (LOD) (0.198 mg L −1 ) and the quantitation limit (LOQ) (0.662 mg L −1 ) were determined as described in our previous article [54].…”

“…Addressing the study of individual phenolic compounds is therefore virtually impossible. In this sense, the TPC was determined by the Folin-Ciocalteu methodology as described by Aliaño-González et al [54]. So, in order to produce a standard curve, a solution of gallic acid in methanol (1000 mg L −1 ) was diluted (ranging from 0.1 up to 500 mg L −1 ) in methanol.…”