2697 Research Article Received: 20 June 2018 Revised: 16 October 2018 Accepted article published: 22 October 2018 Published online in Wiley Online Library: 28 January 2019 (wileyonlinelibrary.com) DOI 10.1002/jsfa.9437 Effect of carob variety and roasting on the antioxidant capacity, and the phenolic and furanic contents of carob liquors Raquel Rodríguez-Solana, a,b José M Salgado, c Efrén Pérez-Santín d and Anabela Romano a,b* Abstract BACKGROUND: The production of the traditional carob liquor from Algarve (Portugal) depends on numerous factors such as carob processing, variety and maceration conditions. An experimental design with 36 runs was created to evaluate the effect of the roasting temperature, particle size, variety of carob and time of maceration on several parameters of carob liquors as gallic acid and total phenolic content, the furanic composition (furfural and 5-(hydroxymethyl)furfural), browning index and in vitro antioxidant capacity. RESULTS: The results revealed that carob variety was the independent variable with the greatest effect on antioxidant capacity, total phenolic and gallic acid content. In particular, AIDA liquors presented the highest results, mainly those prepared with unroasted carob. Meanwhile, Galhosa and Mulata liquors showed the greatest concentrations when the carob pulp was roasted at 150 ∘ C. The furanic composition and browning index were greatly influenced by the carob roasting degree. CONCLUSION: The levels of the main toxic furanics present in carob liquors, furfural and 5-(hydroxymethyl)furfural, suggest a safe consumption of these beverages even in samples of carobs with the maximum roasting degree. The smallest carob particle size favoured the highest phenolic extraction, while the longest maceration periods decreased the concentration of the toxic furanic compounds studied. © 2018 Society of Chemical Industry Supporting information may be found in the online version of this article. Keywords: Ceratonia siliqua L.; maceration; roasting; phenolic compounds; furanic compounds; antioxidant capacity INTRODUCTION Ceratonia siliqua L. is an evergreen tree widely cultivated in the whole Mediterranean basin and other Mediterranean-like regions. According to Food and Agriculture Organization of the United Nations statistics, since 2013 Portugal has positioned as the world leader in carob pod production (about 25% of total world produc- tion), the bean-like fruit of the C. siliqua. 1 The carob fruit contains two major parts: the pulp (90%) and the seeds (10%). 2 Carob pulp is considered a by-product of the seed industry and is commercialized in kibbles or powder (both roasted or unroasted). 3–5 This part of the fruit has been widely used in the past as human food in times of scarcity or famine and in the diet of farm animals. 6 Nowadays, global demand for natural and healthy foods is helping to drive a resurgence in carob consumption. Carob pulp is used as a cocoa replacer because of its similar aroma and the fact that it is caffeine and theobromine-free. In addition to these characteristics, the nutritional components such as impor- tant amino acids (aspartic and glutamic acids, alanine, leucine, etc), minerals (K, Ca, Na and Fe) 7 and vitamins (B3, B6, B9, C, D and E), 8 and other components as high levels of dietary fiber, pheno- lics (gallic acid (GA) as the major constituent) 9 and sugars (mostly sucrose), 10 make carob pulp an important component in different food preparations. Those include the elaboration of carob liqueurs in different countries comprising the main carob world produc- ers e.g. licor de alfarroba (Portugal), licor de algarrobo (Spain) and liquore di carrubo (Italy). 8,11 This type of liqueur occupies the top of production in Algarve, the largest carob producing region in Portugal. 12 The phenolic and antioxidant capacity of carob products depend mainly on the carob variety and technological factors associated to carob pulp processing. 13 The carob roasting is a crucial factor ∗ Correspondence to: A Romano, Faculdade de Ciências e Tecnolo- gia, Universidade do Algarve, Campus de Gambelas, Faro, Portugal. E-mail: aromano@ualg.pt a Faculdade de Ciências e Tecnologia, Universidade do Algarve, Campus de Gambelas, Faro, Portugal b Centro para os Recursos Biológicos e Alimentos Mediterrânicos (MeditBio), Universidade do Algarve, Faro, Portugal c CEB-Centre of Biological Engineering, University of Minho, Campus de Gualtar, Braga, Portugal d Graduate school of Engineering and Technology, International University of La Rioja (UNIR), Logroño, Spain J Sci Food Agric 2019; 99: 2697–2707 www.soci.org © 2018 Society of Chemical Industry