Exploring Antioxidant Activity, Organic Acid, and Phenolic Composition in Strawberry Tree Fruits (Arbutus unedo L.) Growing in Morocco

Hafida Zitouni; Lahcen Hssaini; Rachida Ouaabou; Manuel Viuda-Martos; Francisca Hernández; Sezai Ercisli; Said Ennahli; Zerhoune Messaoudi; Hafida Hanine

doi:10.3390/plants9121677

Exploring Antioxidant Activity, Organic Acid, and Phenolic Composition in Strawberry Tree Fruits (Arbutus unedo L.) Growing in Morocco

Plants (Basel). 2020 Nov 30;9(12):1677. doi: 10.3390/plants9121677.

Authors

Hafida Zitouni¹, Lahcen Hssaini², Rachida Ouaabou³, Manuel Viuda-Martos⁴, Francisca Hernández⁵, Sezai Ercisli⁶, Said Ennahli⁷, Zerhoune Messaoudi⁷, Hafida Hanine¹

Affiliations

¹ Laboratory of Bioprocess and Bio-interfaces, Faculty of Science and Technics, University Sultan Moulay Slimane, BO 523, Beni-Mellal 23000, Morocco.
² Research Unit of Plant Breeding and Plant Genetic Resources Conservation, National Institute for Agricultural Research (INRA), BO 578, Meknes 50000, Morocco.
³ LICVEDDE/ERIDDECV (Research Team of Innovation and Sustainable Development & Expertise in Green Chemistry), Faculty of Science Semlalia, Cadi Ayyad University, Marrakesh 40000, Morocco.
⁴ Departamento de Tecnología Agroalimentaria, Tecnología Agroalimentaria, IPOA, Escuela Politécnica Superior de Orihuela, (Universidad Miguel Hernández), Ctra Beniel, km 3.2, E-03312 Orihuela, Spain.
⁵ Grupo de Investigación de Producción Vegetal y Tecnología, Departamento de Producción Vegetal y Microbiología, Producción Vegetal y Microbiología, Cuela Politécnica Superior de Orihuela (Universidad Miguel Hernández de Elche), Ctra. de Beniel, km 30.2, E-03312 Orihuela, Spain.
⁶ Department of Horticulture, Agricultural Faculty, Ataturk University, 25240 Erzurum, Turkey.
⁷ Department of Arboriculture, Horticulture and Viticulture, National School of Agriculture, (ENA), BO S/40, Meknes 50000, Morocco.

Abstract

This study aimed to explore the main biochemical components and the antioxidant capacity of five strawberry tree fruits using three antioxidant essays within the ecotypic comparison scheme, to find out the most valuable fruit presenting disease-preventing properties. Total phenols, total flavonoids, total anthocyanins, antioxidant activity (DPPH, ABTS, and β-Carotene bleaching assays), pH, titratable acidity, soluble solids, and moisture content were investigated in five strawberry tree genotypes belonging to several areas in Morocco. Phenolic compounds were also identified using high performance chromatography (HPLC), with a diode array detector (DAD). High significant differences (p ˂ 0.05) were revealed among the examined genotypes regarding their total phenols (25.37-39.06 mg gallic acid equivalents (GAE)/g Dry weight (DW), total flavonoids (3.30-7.07 mg RE/g Dry weight (DW), total anthocyanins (0.15-0.64 mg cya-3-glu/100g Dry weight (DW), pH (2.44-3.92), titratable acidity (0.65-1.01 g malic acid/100g Fresh weight (FW), and soluble solids (14.83-18.53%). The average radical scavenging capacity, assessed using three methods, exhibited the following concentration ranges: 3.33-21.08, 2.25-19.58, and 1.08-13 mg Ascorbic Equivalent (AAE/g Dry weight(DW) for the DPPH scavenging test, ABTS, and β-carotene bleaching, respectively. Seventeen phenolic compounds were identified in sampled cultivars. Gallocatechol and catechin were found to be the major phenolic compounds. The correlation matrix revealed significant correlations among investigated variables, particularly ABTS and DPPH. The principal component analysis showed that the first three components formed 90.25% of the total variance. The following variables: chlorogenic acid, ellagic acid derivative, ellagic acid, rutin, and cyanidin-30.5-diglucoside, were the most involved in the total variance. The results revealed highly promising physico-biochemical profiles within the studied strawberry tree genotypes.

Keywords: Arbutus unedo L; antioxidant activity; organic acid; polyphenolic profiles.