Screening and Characterization of Phenolic Compounds from Australian Grown Bananas and Their Antioxidant Capacity

Abstract

Bananas are an essential source of staple food and fruit worldwide and are widely regarded as the world’s largest fruit crop, with more than 100 million tons total annual production. Banana peel, a by-product that represents about 40% of the entire banana’s weight, and pulp are rich in bioactive compounds and have a high antioxidant capacity. As the production of polyphenols in fruit and vegetables is highly dependent on environmental conditions, genetic factors, and the level of maturity, this study aims to characterize six Australian banana cultivars in various stages of ripening for their phenolic compounds using the liquid chromatography-electrospray ionization quadrupole time of flight mass spectrometry (LC-ESI-QTOF-MS/MS), polyphenols quantification with the high-performance liquid chromatography coupled with photodiode array detector (HPLC-PDA), and their antioxidant capacity. All bananas were analysed for total polyphenols content (TPC), total flavonoids content (TFC), and total tannin content (TTC) and their antioxidant activities. Ripe Ducasse peel and pulp contained the highest amounts of total polyphenols content (1.32 and 1.28 mg gallic acid equivalent (GAE) per gram of sample), total tannin contents (3.34 mg catechin equivalent (CE) per gram of sample), and free radical scavenging capacity (106.67 mg ascorbic acid equivalent (AAE) per g of sample). In contrast, ripe Plantain peel had the greatest total flavonoids (0.03 mg quercetin equivalent (QE) per g of sample). On the other hand, unripe Ladyfinger pulp possessed the highest total antioxidant activity (1.03 mg AAE/g of sample). There was a positive correlation between flavonoids and antioxidant activities. By using LC-ESI-QTOF-MS/MS, a total of 24 phenolic compounds were tentatively characterized in this research, including six phenolic acids, 13 flavonoids, and five other polyphenols. Quantification of phenolic compounds by the high-performance liquid chromatography coupled with photodiode array detector (HPLC-PDA) revealed a higher content of phenolic acids. These findings confirmed that banana peel and pulp have considerable antioxidant activity and can be employed in human food and animal feed for variant health enhancement uses.

Profiling of Phenolic Compounds of Fruit Peels of Different Ecotype Bananas Derived from Domestic and Imported Cultivars with Different Maturity

“…The above results verified that the type and content of phenolic compounds in banana peel were varied depending on the variety of banana [11,16]. Similarly, research by Bashmil et al, showed that the highest phenolic compound contents were found in the ripe Ducasse peel, unripe Ladyfinger peel, ripe Plantain peel, and unripe Monkey peel, which contained 1.32, 1.15, 0.87, and 0.79 mg GAE/g, respectively [38]. Baskar et al [39] also found that among the nine local cultivars from Tamil Nadu, India, Poovan cultivar had less total phenolic compound content (0.39 mg catechol equivalent (CE)/g), but higher level of flavonoids (22.83 mg rutin equivalent (RE)/g) in comparison with other cultivars, such as Sevvazhai, Nendran, and Rasthali.…”

Comparative Evaluation of the Phytochemical Profiles and Antioxidant Potentials of Olive Leaves from 32 Cultivars Grown in China

“…As expected, the high-oil-content cultivars had the lowest antioxidant values (Figure S2D,E). In addition, the variations between the results of the DPPH, ABTS, and FRAP assays were attributed to the use of different radicals in the different methods, as the various compounds reacted differently with the employed radicals [42]. Consequently, our findings showed that combining antioxidant capacity assays was more accurate than using only the DPPH assay.…”

“…A previous study reported that the antioxidant activity of oleuropein was mainly due to the aglycones (i.e., hydroxytyrosol moietyin) in its structure [13]. The antioxidant activity of plant-derived samples has shown to be a complicated action that could be synergistically promoted by the various phenolic compounds in the plant [42].…”

LC-MS/MS-QTOF Screening and Identification of Phenolic Compounds from Australian Grown Herbs and Their Antioxidant Potential

“…Consequently, the scavenging of • OH radicals by herbal extracts could provide a significant protection to biological damage against these free radicals. Phosphomolybdenum antioxidative power assay (PMAP assay) is used to measure the reduction capacity of molybdenum (VI) to molybdenum (V) by an antioxidant phenolic compound and subsequent formation of a green molybdenum (V)/phosphate complex [ 27 , 28 ]. The results of PMAP assay indicate that rosemary and bay have significantly higher total antioxidant activity (21.93 ± 2.82 and 18.53 ± 0.16 mg AAE/g, respectively) than other listed herbs [ 27 , 28 ].…”