Chemical Composition of Cynara Cardunculus L. var. altilis Heads: The Impact of Harvesting Time

Filipa Mandim,Celestino Santos-Buelga,Spyridon A Petropoulos,Ângela Fernandes,Isabel C F R Ferreira,Lillian Barros

doi:10.3390/agronomy10081088

Filipa Mandim, Celestino Santos-Buelga + Show 4 more

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https://doi.org/10.3390/agronomy10081088

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Abstract

Cardoon is a multi-purpose crop with several industrial applications, while the heads (capitula) are edible and commonly used in various dishes of the Mediterranean diet. Several reports in the literature study the chemical composition of the various plants parts (leaves, flower stalks, bracts, seeds) aiming to industrial applications of crop bio-waste, whereas for the heads, most of the studies are limited to the chemical composition and bioactive properties at the edible stage. In the present study, cardoon heads were collected at six different maturation stages and their chemical composition was evaluated in order to determine the effect of harvesting stage and examine the potential of alternative uses in the food and nutraceutical industries. Lipidic fraction and the content in fatty acids, tocopherols, organic acids, and free sugars were determined. Lipidic content decreases with the maturation process, while 22 fatty acids were detected in total, with palmitic, oleic, and linoleic acids being those with the highest abundance depending on harvesting time. In particular, immature heads have a higher abundance in saturated fatty acids (SFA), whereas the samples of mature heads were the richest in monounsaturated fatty acids (MUFA). The α-tocopherol was the only isoform detected being present in higher amounts in sample Car B (619 µg/100 g dw). Oxalic, quinic, malic, citric and fumaric acids were the detected organic acids, and the higher content was observed in sample Car E (15.7 g/100 g dw). The detected sugars were fructose, glucose, sucrose, trehalose and raffinose, while the highest content (7.4 g/100 g dw) was recorded in sample Car C. In conclusion, the maturation stage of cardoon heads influences their chemical composition and harvesting time could be a useful means to increase the quality and the added value of the final product by introducing this material in the food and nutraceutical industries.

Highlights

Cynara cardunculus L., or commonly known as cardoon, belongs to the Asteraceae family which is one of the largest families of the plant kingdom with more than 2000 species
Considering the lack of information in the scientific literature, the aim of this study was to determine the impact of the maturation stage on the lipidic content and on the profile of fatty acids, tocopherols, organic acids, and free sugars present in cardoon heads collected in central Greece and to evaluate alternative uses of cardoon heads that are overripe, e.g., they have passed the edible stage
Our results showed that the saturated fatty acids (SFA) were the most abundant class of fatty acids in heads of early maturity (Car A–C), whereas monounsaturated fatty acids (MUFA) were the predominant ones in the remaining samples

Summary

Introduction

Cynara cardunculus L., or commonly known as cardoon, belongs to the Asteraceae family which is one of the largest families of the plant kingdom with more than 2000 species. Cynara cardunculus comprises three botanical varieties, all native to the Mediterranean basin, the wild cardoon Scolymus) [1,2] This crop has been gaining attention due to the high biological and industrial potential that it has Agronomy 2020, 10, 1088; doi:10.3390/agronomy10081088 www.mdpi.com/journal/agronomy. Cardoon is a species highly resistant to the fluctuation of weather conditions with low precipitation and hot and dry summers, characteristic of the Mediterranean basin climate. Its high resistance against adverse conditions and weather extremities, together with its multifaceted applicability, favor its exploration and the multiple uses in different industrial applications [4,5]. The industrial applications of cardoon are diverse, since it is used as plant rennet in the food industry to produce cheeses of protected designation of origin (PDO) [6,7]; it is used for the production of paper pulp, due to its high content in cellulose and hemicellulose [8,9], as well as for bioenergy and biomass production [1,10,11]

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