A DPPH· Kinetic Approach on the Antioxidant Activity of Various Parts and Ripening Levels of Papaya (Carica papaya L.) Ethanolic Extracts.

Olimpia Alina Iordănescu,Marius Ioan Cugerean,Mircea Riviş,Daniel Ioan Hădărugă,Mircea Ionuţ Petroman,Simelda Elena Zippenfening,Dina Gligor (Pane),Nicoleta Gabriela Hădărugă,Maria Băla

doi:10.3390/plants10081679

Abstract

Papaya fruits (Carica papaya L.) are valuable both as food, including concentrates and mixed beverages and in traditional medicine. The goal of the study was to evaluate the antioxidant activity of various parts of unripe and ripe papaya fruit from the DPPH· kinetics point of view. Peel, pulp, seed, and seed-pulp of unripe and ripe papaya fruits (¼ and >¾ level of ripening) were extracted with ethanol and monitored at 517 nm in the presence of DPPH·. The radical scavenging capacity (RSC) at various time ranges and DPPH· reaction rates for specific time intervals were determined. The highest RSC values were obtained for papaya pulp extracts, consistently higher for the ripe samples in comparison with the unripe ones (86.4% and 41.3%). The DPPH· rates significantly differ for the unripe and ripe papaya extracts, especially for the first time range. They are more than double for the ripe papaya. These values were 2.70, 4.00, 3.25, 2.75 μM/s for the peel, pulp, seed, seed-pulp extracts from the ripe papaya and only 1.00, 1.65, 1.40, 1.80 μM/s for the unripe samples. DPPH· kinetic approach can be useful for a fast and simple evaluation of the overall antioxidant properties of fruit extracts.

Highlights

Papaya is the generic name of the tree and fruit of Carica papaya L., which belongs to the genus Carica, botanical family Caricaceae
A DPPH· kinetic approach for discriminating between the unripe and ripe papaya (Carica papaya L.) fruit ethanolic extracts was proposed for the first time
The DPPH· reaction rates are significantly different in the case of interaction with the antioxidant compounds from the ripe and unripe papaya extracts for the beginning of the reaction

Summary

Introduction

Papaya is the generic name of the tree and fruit of Carica papaya L., which belongs to the genus Carica, botanical family Caricaceae. It originates from Central and South America but is cultivated in all tropical regions. The composition of papaya fruit is different for unripe and ripe papaya, as well as for the various parts of the fruit Nutritional compounds such as proteins, lipids, and fibers are more concentrated in the ripe fruits (up to 2%, 0.6%, and 1.7% in comparison with 1.1, 0.5, and 1.3% for the unripe fruit, respectively) [1,5]. Regarding the composition of the seed, the lipid fraction is the most concentrated (up to 60%), but soluble and insoluble proteins (up to 28%, mainly consisting of globulins—more than a half) and fibers (~23%) are important [6,12]

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