Characterization of Phenolics in Rejected Kiwifruit and Their Antioxidant Potential

Abstract

Kiwifruit hold significant nutritional value and are a good source of antioxidants due to their diverse range of bioactive compounds. Kiwifruit waste is generated throughout the food supply chain, particularly during transportation and storage. Kiwifruit rejected from the retail market due to unfavorable appearance still possess potential economic value as kiwifruit are abundant in phenolic compounds. The present work studied the phenolic profile and antioxidant potential of rejected kiwifruit, including SunGold (Actinidia chinensis), Hayward (Actinidia deliciosa), and round organic Hayward (Actinidia deliciosa). Regarding phenolics estimation, SunGold possessed the highest TPC (0.72 ± 0.01 mg GAE/g), while Hayward exhibited the highest TFC (0.05 ± 0.09 mg QE/g). In antioxidant assays, SunGold showed the highest antioxidant activities in DPPH (0.31 ± 0.35 mg AAE/g), FRAP (0.48 ± 0.04 mg AAE/g), ABTS (0.69 ± 0.07 mg AAE/g), •OH-RSA (0.07 ± 0.03 mg AAE/g) assays, and FICA (0.19 ± 0.07 mg EDTA/g), whereas Hayward showed the highest RPA (0.09 ± 0.02 mg AAE/g) and TAC (0.57 ± 0.04 mg AAE/g). Separation and characterization of phenolics were conducted using LC-ESI-QTOF-MS/MS. A total of 97 phenolics were tentatively characterized from rejected SunGold (71 phenolics), Hayward (55 phenolics), and round organic Hayward (9 phenolics). Hydroxycinnamic acids and flavonols were the most common phenolics characterized in the three samples. The quantitative analysis was conducted by HPLC-PDA and found that chlorogenic acid (23.98 ± 0.95 mg/g), catechin (23.24 ± 1.16 mg/g), and quercetin (24.59 ± 1.23 mg/g) were the most abundant phenolics present in the rejected kiwifruit samples. The notable presence of phenolic compounds and their corresponding antioxidant capacities indicate the potential value of rescuing rejected kiwifruit for further utilization and commercial exploitation.

Determination and Characterization of Phenolic Compounds from Australia-Grown Sweet Cherries (Prunus avium L.) and Their Potential Antioxidant Properties

“…The radical-scavenging activity of cherry samples was determined by the DPPH assay according to Subbiah et al 54 and Zhu et al 65 A total of 25 μL of the sample extract and 275 μL of 0.1 mol/L DPPH radical methanol solution were mixed in a 96-well plate and incubated in the dark for 30 min. The absorbance was measured at 517 nm.…”

Screening of Polyphenols in Tobacco (Nicotiana tabacum) and Determination of Their Antioxidant Activity in Different Tobacco Varieties

“…2,2′-Diphenyl-1-picrylhydrazyl (DPPH) Antioxidant Assays. The process was based on the published protocol of Zhu et al 64 DPPH solution was diluted with analytical grade methanol to 0.1 M. Forty microliters of the extraction was added into 260 μL of DPPH radical methanol solution in a 96well plate and incubated for 30 min at 25 °C. The standard curve was generated by ascorbic acid solution with 0−30 μg/ mL.…”

Comprehensive Profiling of Most Widely Used Spices for Their Phenolic Compounds through LC-ESI-QTOF-MS2 and Their Antioxidant Potential

“…The antioxidant assays were carried out by following the protocols of Subbiah, et al [9], Suleria, et al [10] and Zhu, et al [11] with some modifications, all tests were performed in triplicate. The 96-well plates were used to determine the potential of each spice extract.…”