Research Article iMedPub Journals Journal of Food, Nutrition and Population Health 2020 www.imedpub.com Vol. 4 No. 2: 17 ISSN 2577-0586 DOI: 10.21767/2577-0586.4.2.17 Phenolic Compounds Identification and Antioxidant Umar Lule Ssonko1* and Activity in Bananas of AAB and ABB Genomes Florence Isabirye Muranga2 Grown in Uganda 1 Department of Food Science & Technology, Makerere University, P.O. Box 7062, Kampala, Uganda 2 Presidential Initiative on Banana Industrial development (PIBID), P.O. Box Abstract 35747 Kampala, Uganda A few reports have shown bananas to contain varying amounts of phenolic compound and their composition and quantity is known to be influenced by various factors. Two banana triploid varieties (AAB) and (ABB) were investigated *Corresponding author: for their total phenolic content and antioxidant activities at two maturity levels. Umar Lule Ssonko The peels for both varieties contained higher polyphenols content (159.77- 182.74 GAE mg/100 g) than the pulps (42.85-54.04 GAE mg/100 g) in mature bananas. However, the pulp contained higher polyphenolic content (414.94- [email protected] 523.60 GAE mg/100 g) than the peels when the bananas were young (150.48- 199.61 GAE mg/100 g). The antioxidant activity as measured by DPPH and FRAP Department of Food Science & Technology, revealed that the banana samples that were studied exhibited a high antioxidant Makerere, Kampala, Uganda activity irrespective of the variety, plant part and growth stage. Additionally, characterization of the phenolic compounds revealed that Mature Gonja (AAB) peel had a higher number of polyphenolic compounds identified such as Rutin and Tell: +256-782-973-230 its derivatives as well as Kaempferol derivatives. Keywords: Bananas; Phenolic compounds; Antioxidant activity; DPPH; FRAP Citation: Ssonko UL, Muranga FI (2020) Phenolic Compounds Identification and Antioxidant Activity in Bananas of AAB and Received: March 15, 2020, Accepted: March 22, 2020, Published: March 28, 2020 ABB Genomes Grown in Uganda. Br J Res Vol. 4 No. 2: 17. Introduction Over the recent decades, phenolic compounds have been a countries/) and most of it is consumed locally thus neglibly subject of high interest owing to their possible association with contributing to world banana exports. Various studies have intake and the prevention of these major chronic diseases as evidenced that both banana pulp and peel contain various suggested by clinical trials and epidemiological studies [1]. The phenolic compounds such as catechin, epicatechin, lignin and increase in intensity and scope of investigations with respect to tannins and anthocyanins [3]. A study [4] reported that in general the phenolic compounds has been due to their high spectrum the peel extracts of eight Malaysian bananas (Musa sp.) exhibited of biological activities, including antioxidant, anti-inflammatory, higher total phenolic content and stronger antioxidant activities antibacterial, anti-cancer and antiviral functions [2]. than their corresponding pulps. Due to broadening spectrum of Despite the human body having effective defense mechanisms polyphenol applications and the desire by various governments to safeguard the cellular molecules against ROS induced damage in developing countries as well as development agencies to via mainly enzymatic and non-enzymatic antioxidant systems, promote regional economies and sustainable agricultural these natural defenses are most likely inadequate for severe or activities, diversification of the use of locally available material continued oxidative stress notwithstanding that these system’s has been sought in recently. protective ability decreases with age. Consequently, in order to Bananas have been reported to contain considerable amounts of maintain adequate amounts of antioxidants in the human body, bioactive phytochemicals in the fruit pulp with the average values there is need to utilize external source of antioxidants via the for the total phenolic compounds ranging from 44.46 to 52.02 mg normal diet or supplements. of catechin equivalent/100 g of fresh weight, respectively [5,6]. Bananas are among the most popular fruits on the world Whereas phenolic compounds from many fruits have been market. Uganda ranks only behind India in banana production intensively studied, comparatively few works on the phenolic in the world with about 12 million tons per annum (https:// composition and/or content of banana fruits have been carried www.worldlistmania.com/worlds-largest-bananas-producing- out such as: The total amount of phenolic compounds in banana © Under License of Creative Commons Attribution 3.0 License | This article is available from: https://www.imedpub.com/food-nutrition-and-population-health/ 1 Journal of Food, Nutrition and Population Health 2020 Vol. 4 No. 2: 17 ISSN 2577-0586 (Musa acuminata Colla AAA) peel was reported to range from Materials and Methods 0.90 to 3.0 g/100 g DW [7]. A study [3] identified gallocatechin in the banana (Musa Cavendish), which was found more abundant Plant materials in the peel (158 mg/100 g dry wt) than in pulp (29.6 mg/100 g dry The roasting bananas plantain type (Musa acuminata) AAB wt). Banana pulp was also reported to have phenolic compounds genotype) known locally as Gonja and the cooking/juice type like catechin and epicatechin [7]. A study [8] reported that the bananas (Musa acuminata) ABB genotype known locally as banana peel contained a greater range of phenolics composition. Kivuvu were used throughout this investigation were grown at The rhizomes of commercial banana cultivars grown in India were the PIBID garden in Bushenyi district in Uganda. The mature and reported to contain phenolic compounds such as cinnamic acid, young Gonja banana (AAB genotype) and the mature and young gentisic acid, protocatechuic acid, caffeic acid, ferulic acid, (+) Kivuvu bananas (ABB) were used in this study and mature or ready catechin and chlorogenic acid, catechol, gallic acid, chlorogenic for harvest stage was at 15-18 weeks from flowering while the acid, tannic acid, catechol and gallic acid in the different extracts young stage was 4-6 weeks from flowering which was adopted used for extraction [9]. A study [10] reported that, (+) catechin, from [11]. The fresh bananas were harvested and after 48 hrs of gallocatechin, and (-) epicatechin, as well as condensed tannins, transportation, they were kept at -80°C until needed for analyses. were detected in the soluble extract of the banana fruit pulp, two Chemicals and reagents hydroxycinnamic acid derivatives were detected in the soluble cell wall fraction, whereas in the insoluble cell wall fraction of Gallic acid, Folin-Ciocâlteu reagent, Trolox standard (6-hydroxy- bananas, the anthocyanidin delphinidin was reported to be 2,5,7,8,-tetramethyl-chroman-2-carboxylic acid), Sodium predominant. ascorbate, 2,4,6–tri (4-pyridyl)-1,3,5-triazine (TPTZ), HCl, Fecl3.6H2O, FeSO4, 1,1-diphenyl-2-picrylhyrazyl (DPPH), Gallic Although phenolic compounds from some banana varieties have acid, were purchased from Wako Pure Chemical Industries been identified, it is well documented that difference in nutrient Ltd, Osaka, Japan. All other reagents were of analytical grade. composition within even a given banana variety vary considerably Standard solutions were prepared with deionized water. with respect to: region of production, farming method (Organic or inorganic), etc. (Forster et al. (2002). Since to our knowledge, Extraction of polyphenols a comparative evaluation of the polyphenolic compounds and About 2.0 g of the frozen banana pulp and peel samples were antioxidant activities of banana varieties grown in Uganda such taken and weighed directly in Pyrex tubes, containing 20 ml of as the Kivuvu (ABB) and Gonja (AAB) has not been reported acidified ethanol 70% (1% of 1 N hydrochloric acid, pH 3.0) in to date and there is promotion of locally available material as 1:10 ratio (solid: solvent). The use of acidified solvents has been sources of antioxidants, it was found imperative to determine the used by various researchers [12] to extract phenolic compounds total polyphenolic content, phenolic compounds and antioxidant from plant materials and was thus adopted. The samples were capacity of the Kivuvu (ABB) and Gonja (AAB) banana varieties immediately homogenized and extracted in a shaking incubator grown in Uganda. for 2 hrs. After completion of the extraction time, the crude extract was centrifuged at 3000 rpm for 15 min. The supernatant Therefore, this study is of importance as the nutrient composition was collected and kept at -80°C until further analyses. of fruits and vegetables varies greatly with respect to soil type, varieties, environmental conditions, latitude, agronomic Total phenolic content analysis practices, etc. Further the polyphenolic profiles of fruits are dependent on maturity, cultivars, geographical origin, growing Total phenolic content of the banana extracts was determined using Folin-Ciocâlteu method described by a study [13] with season, postharvest storage condition and processing techniques. modifications. 1 mL of banana extract was added to a glass tube Characterization of phenolic compounds in different banana using a pipette and 9 mL of deionized water was added to give a varieties is very important, since phenolics play a significant role dilution of 10 times. 1 mL of the diluted banana extract was taken in the prevention of many chronical diseases. Additionally, though to another glass tube using a pipette and 1 mL of Folin-Ciocâlteu the banana peel is