Content of total polyphenols and antioxidant activity in varieties of onion and garlic

Ismael Sulaiman Dalaram

doi:10.5219/658

Abstract

Garlic as onion family and the most important Allium species consumed all over the world. Garlic possesses potential health promoting effects due to its high phenolic content and a good source of vitamins, minerals and major component like polyphenols, flavonoids, thiosulfinates and other sulfur compounds. Red onion and garlic are among the important parts of diet in many world populations, and there is also a long-held belief in their health enhancing properties. In this work evaluated content of total polyphenols and antioxidant activity in onion and garlic. Samples of plant material (onion, garlic) were collected at the stage of full maturity in the village (Harmota) in Koysinjac town in Erbil city. The content of the total polyphenols was determined by using the Folin-Ciocalteu reagent (FCR). Antioxidant activity was measured by using a compound DPPH (2.2-diphenyl-1-picrylhydrazyl). Phenolic content and antioxidant activities of one variety of garlic and four varieties of onions have been studied. In the present experiment it was detected, that total polyphenols content in samples onion ranges from 626.61 - 322.83 mg.kg-1 (onion) and 506.7 mg.kg-1 for (garlic). Statistically significant highest value of total polyphenols was recorded in red onion the lowest content of total polyphenols was recorded in white onion 322.83.mg.kg-1, and statistically significant highest value of antioxidant activity was recorded in red onion (33.42%) the lowest value was in white onion (22.68%). The value of antioxidant activity of garlic was (28.47%). Data analysis showed that the red variety onion presents highest value of total polyphenolic compounds. Consequently, antioxidant capacity was highest for red variety compared to other variety of onion and garlic. The order value of TPC was follow: Red Onion (626.61) >Garlic (506.70) >yellow onion (423.94) >pink onion (345.36) >white onion (322.83). Based on the measured values of AOA in onion and garlic samples can be classified as follows: Red Onion (33.42) >Garlic (28.47 >yellow onion (25.95) >pink onion (23.74) >white onion (22.68).

Highlights

Plants and plant-derived produce are among the prime utilities of mankind for food, shelter and cure since the dawn of civilization and it wouldn’t be inappropriate to state that the use of medicinal plants predates written human history (Harrison et al, 2015)
Kavalcova et al (2014), published the interval of statistically significant highest value of antioxidant activity was recorded in onion from 20.22 ±0.53% to 25.76 ±0.53% and statistically significant the lowest value of antioxidant activity was recorded in garlic from 4.05 ±0.20% to 5.07 ±0.47%, our measured values of AOA in onion and garlic samples can be classified as follows: Red Onion (33.42%) >Garlic (28.47% >yellow onion (25.95%) >pink onion (23.74%) >white onion (22.68%)
The phenolic content, antioxidant activity, and the correlation between phenolic content and antioxidant capacity were studied in varieties onion and garlic, Cultivar significantly affected phenolic accumulation and antioxidant capacity

Summary

Introduction

Plants and plant-derived produce are among the prime utilities of mankind for food, shelter and cure since the dawn of civilization and it wouldn’t be inappropriate to state that the use of medicinal plants predates written human history (Harrison et al, 2015). Evaluation of total polyphenol content and values of antioxidant capacity in onion and garlic In comparison to our determined values (322.83 mg.kg-1 GAE) of polyphenols content in white variety, their results were lower.

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Conclusion