Effect of carob variety and roasting on the antioxidant capacity, and the phenolic and furanic contents of carob liquors

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

Physicochemical and aromatic characterization of carob macerates produced by different maceration conditions

“…The carob flour production process has an important influence on the polyphenolic patterns, and roasted carob products contain the highest levels of gallic acid. Rodríguez‐Solana, Salgado, et al () showed noticeable phenolic and antioxidant differences between liqueur prepared with different carob varieties and depending of flour particle size. Furthermore, concerning the macerates, there was a strong positive correlation between the TPC and the antioxidant activity determined by FRAP assay (Figures and ) which indicate the significant contribution of the carob phenolic compounds to macerates antioxidant activity.…”

“…Recently, researchers have focused on the valorization of carob pods since they are an excellent source of sugar (Boublenza et al, ; Bulca, ; Mazaheri et al, ; Turhan, Bialka, Demirci, & Karhan, ) as well as bioactive compounds such as polyphenols which can be efficiently extracted by the maceration of chopped carob pods in hydroalcoholic base (Goulas, Stylos, Chatziathanasiadou, Mavromoustakos, & Tzakos, ; Nasar‐Abbas et al, ; Rodríguez‐Solana, Salgado, et al, ). Obtained liqueur is a desirable, aromatic drink with potential health benefits, and the amount of extracted compounds depends on the maceration conditions (Rodríguez‐Solana, Coelho, et al, ; Rodríguez‐Solana, Salgado, et al, ). The highest TPC values were found in the samples in which carob was macerated in lower strength alcoholic base (50% v/v and 30% v/v) and exposed to darkness.…”

“…For example, at higher alcohol percentage essential oils, lipids, and resins are dissolved, while at lower alcohol percentage substances soluble in water (organic acids, bitter substances, and carbohydrates) are dissolved. There are only a few scientific researches on carob‐based alcoholic drinks and on the nutritional characteristics of the carob liqueur (Rodríguez‐Solana, Carlier, Costa, & Romano, ; Rodríguez‐Solana, Salgado, et al, ). Rodríguez‐Solana, Salgado et al () investigated the process of maceration of carob in order to extract as many of the bioactive compounds as possible.…”

“…There are only a few scientific researches on carob‐based alcoholic drinks and on the nutritional characteristics of the carob liqueur (Rodríguez‐Solana, Carlier, Costa, & Romano, ; Rodríguez‐Solana, Salgado, et al, ). Rodríguez‐Solana, Salgado et al () investigated the process of maceration of carob in order to extract as many of the bioactive compounds as possible. The results showed that gallic acid is the most abundant bioactive compound in the carob liqueur, and the amount of both gallic acid and total phenolic compounds significantly dependent on the carob cultivar characteristics.…”

“…Despite the scarce scientific data on herbal/fruit liqueurs, there are some researches dealing with the development of these kinds of alcoholic drinks. Maceration parameters (type and strength of water‐alcohol base, maceration time, temperature, solid/liquid ratio) influence the quality of the macerate (Caldeira, Lopes, Delgado, Canas, & Anjos, ; Galego, Jockusch, & Da Silva, ; Gironés‐Vilaplana, Calín‐Sánchez, Moreno, Carbonell‐Barrachina, & García‐ Viguera, ; Jovanović et al, ; Rodríguez‐Solana, Coelho, et al, ; Rodríguez‐Solana, Salgado, Pérez‐Santín, & Romano, ; Rodríguez‐Solana, Vázquez‐Araújo, et al, ). For example, at higher alcohol percentage essential oils, lipids, and resins are dissolved, while at lower alcohol percentage substances soluble in water (organic acids, bitter substances, and carbohydrates) are dissolved.…”