Evaluation of Polyphenols and Antioxidant Capacity of Fruits and Vegetables Using a Modified Enzymatic Extraction Method

Abstract

Fruits and vegetables are an essential part of the human diet, and several epidemiological studies show that the content of natural antioxidants, especially fl avonoids, may be benefi cial in protecting the human body against damage induced by reactive species. This is important for maintaining physiological redox equilibrium (1,2). These foods supply several antioxidants, such as ascorbic acid (vitamin C), tocopherols and tocotrienols (vitamin E), carotenoids (provitamin A), and several phenolic compounds (fl avones, isofl avones, fl avanones, anthocyanins and catechins) (3,4 SummaryFruits and vegetables are considered a good source of polyphenols and antioxidant capacities which are benefi cial in protecting the human body against damage induced by reactive species. The objective of this work is to conduct an assessment of the polyphenol content and antioxidant activities of diff erent fruit (kiwi, pear, green apple, raspberry, blackberry, strawberry and blueberry) and vegetable (pumpkin, green and red pepper) extracts using both chemical extraction and a modifi ed in vitro digestive enzymatic extraction in order to compare results. Polyphenol content and antioxidant capacity of diff erent fruits, vegetables and fruit juices were determined by Folin-Ciocalteu and FRAP methods, respectively. It was observed that polyphenol content expressed as gallic acid equivalents of extracts obtained with the two extraction methods was signifi cantly (p<0.05) diff erent (on average 310.3 and 231.8 mg per 100 g of fresh sample in enzymatic and methanolic extracts, respectively). Antioxidant capacity was also signifi cantly (p<0.05) diff erent in the extracts obtained by the two methods, with higher values in enzymatic extracts (1.91 mmol of Fe 2+ per 100 g of fresh sample). Analyses of apple samples with and without skin also revealed important diff erences related to methodology and composition. Additionally, the original enzymatic extraction method was improved to avoid interferences caused by the presence of protein residues in the extract.

LC-ESI-QTOF/MS Characterisation of Phenolic Acids and Flavonoids in Polyphenol-Rich Fruits and Vegetables and Their Potential Antioxidant Activities

“…Mango is rich in xanthones and flavonols, and most of the phenolic compounds exist in peel [23], and blueberry rich in phenolic acids, flavonoids and anthocyanins [24]. Similar trends but with higher values in TPC were reported previously in Chile fruit samples (harvested from Santiago, Chile) like blueberry (4.75 ± 0.34 mg GAE/g) and strawberry (4.02 ± 0.14 mg GAE/g) compared to pear (0.99 ± 0.07 mg GAE/g) extracted with different solvent methanol [25]. These higher TPC values might be due to the difference of fruit grown at different climate and region also extracted with different solvent.…”

The Potential Role of Creatine in Vascular Health

“…Despite the lifelong pressure put upon our antioxidant defenses, fortunately antioxidants also exist in a variety of natural sources that we can ingest through our diet. For example, foods rich in polyphenols [ 107 ], carotenoids [ 108 ], lycopene [ 109 ], vitamins (A, C and E) [ 110 ], and flavonoids [ 111 ], have all been shown to support the body’s natural antioxidant defenses. It is due to the benefit of these naturally occurring antioxidants that antioxidant-containing foods and supplements have been well researched [ 44 , 112 , 113 ] and used as a therapeutic strategy for the treatment of many diseases.…”

Antioxidant, antimicrobial, and antiproliferative activity-based comparative study of peel and flesh polyphenols from Actinidia chinensis

“…Studies to date concerning A. chinensis have mainly focused on its genome profiling and factors affecting the quality, bioactive constituents, and bioactivities of the fruit flesh (6–8). Extensive studies have reported the isolation and characterization of phenolic components of kiwifruit flesh by thin-layer chromatography, high performance liquid chromatography and ultra-high performance liquid chromatography (9, 10). Apart from the antioxidant activity, kiwifruit has also shown antimicrobial activity against many pathogenic bacteria: Pseudomonas aeruginosa , Escherichia coli , Listeria monocytogenes , and Staphylococcus aureus (11).…”