The deterioration of fats and oils in foods is responsible for rancid odors and flavors, and leads to decrease in nutritional quality and safety due to the formation of secondary potentially toxic compounds. The addition of antioxidants is used to preserve flavour, color and to avoid vitamin destruction. Nevertheless, toxicological effects and consumer preference for natural products have resulted in an increased interest in the use and research on natural antioxidants. Microbial activity, a primary cause of deterioration of many foods, often is responsible for the loss of quality and safety. Currently there is a growing interest in using natural antibacterial compounds for the preservation of foods. This work was undertaken to explore the potential of some different parts of fruits and vegetables materials as sources of powerful natural antioxidants and antibacterial. The peels, seeds and pulps of 10 kinds of fruits and vegetables commonly consumed and grown in Italy were used. The phenolic compounds were extracted, after optimisation, with ultrasound-assisted extraction, with the following solvents: A, methanol: water: acetic acid; B, ethanol: water; C, acetone: water, to compare the activity of these different extracts. Total phenolic index was determined in the extracts by means Folin Ciocalteu method. The antioxidant activities were evaluated by in vitro experiments, using scavenging assays of 1,1- diphenyl-2-picrylhydrazyl radicals (DPPH). Antibacterial effect of the extracts was then evaluated against 12 food bacteria. These extracts, at 10 mg/ml and 20 mg/ml concentrations, were tested for their antibacterial effect by using the agar diffusion method. Then the profiles of probable polyphenol compounds responsible for the bioactivity were determined by means of HPLC/DAD and HPLC/MS/MS. Total phenolic content was ranged from 212.24 mg to 3.1 mg gallic acid equivalents (GAE)/g dry weight. The peels of Punica granatum sample exhibited a higher phenolic index than other samples, followed by Cornus mas and Rosa canina L. The same samples presented a strongest antioxidant activity in scavenging DPPH radicals. The antioxidant activity was ranged from 4.74% to 95.73%. Generally high correlation coefficient was exhibited between the phenolic content and antioxidant activity.
Polyphenolic extracts and their antimicrobial activies of fruit and vegetables as possible natural additives
GIORDANO, Manuela;ZEPPA, Giuseppe;RANTSIOU, KALLIOPI;
2009-01-01
Abstract
The deterioration of fats and oils in foods is responsible for rancid odors and flavors, and leads to decrease in nutritional quality and safety due to the formation of secondary potentially toxic compounds. The addition of antioxidants is used to preserve flavour, color and to avoid vitamin destruction. Nevertheless, toxicological effects and consumer preference for natural products have resulted in an increased interest in the use and research on natural antioxidants. Microbial activity, a primary cause of deterioration of many foods, often is responsible for the loss of quality and safety. Currently there is a growing interest in using natural antibacterial compounds for the preservation of foods. This work was undertaken to explore the potential of some different parts of fruits and vegetables materials as sources of powerful natural antioxidants and antibacterial. The peels, seeds and pulps of 10 kinds of fruits and vegetables commonly consumed and grown in Italy were used. The phenolic compounds were extracted, after optimisation, with ultrasound-assisted extraction, with the following solvents: A, methanol: water: acetic acid; B, ethanol: water; C, acetone: water, to compare the activity of these different extracts. Total phenolic index was determined in the extracts by means Folin Ciocalteu method. The antioxidant activities were evaluated by in vitro experiments, using scavenging assays of 1,1- diphenyl-2-picrylhydrazyl radicals (DPPH). Antibacterial effect of the extracts was then evaluated against 12 food bacteria. These extracts, at 10 mg/ml and 20 mg/ml concentrations, were tested for their antibacterial effect by using the agar diffusion method. Then the profiles of probable polyphenol compounds responsible for the bioactivity were determined by means of HPLC/DAD and HPLC/MS/MS. Total phenolic content was ranged from 212.24 mg to 3.1 mg gallic acid equivalents (GAE)/g dry weight. The peels of Punica granatum sample exhibited a higher phenolic index than other samples, followed by Cornus mas and Rosa canina L. The same samples presented a strongest antioxidant activity in scavenging DPPH radicals. The antioxidant activity was ranged from 4.74% to 95.73%. Generally high correlation coefficient was exhibited between the phenolic content and antioxidant activity.
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