Anthocyanins from Rubus fruticosus L. and Morus nigra L. Applied as Food Colorants: A Natural Alternative

Erika N Vega,Adriana K Molina,Carla Pereira,Paula Rodrigues,Sandrina A Heleno,Isabel C F R Ferreira,Dejan Stojković,Márcio Carocho,Maria Filomena Barreiro,Maria Inês Dias,Marina Soković,Lillian Barros,João C M Barreira,Isabel P Fernandes

doi:10.3390/plants10061181

Erika N Vega, Adriana K Molina + Show 12 more

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https://doi.org/10.3390/plants10061181

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Abstract

Given the importance of colour in the general acceptance or rejection of a product, the use of colorants is a widespread practice, particularly in the food industry. At the same time, with the increasing consumers’ awareness of the health effects that some artificial colorants can exert, there is a growing tendency to prioritize foodstuffs containing natural additives. In this work, Morus nigra L. and Rubus fruticosus L. fruit juices were characterized in terms of anthocyanins, organic acids, free sugars, and tocopherols, as also regarding their bioactive properties. Given their richness in anthocyanins, this study also aimed to prepare different solid colouring formulations by the spray-drying technique, using as stabilizers maltodextrin and arabic gum. Six free sugars and two organic acids were detected in the fruit juices, as well as the four tocopherol isoforms. Two cyanidin derivatives were found in M. nigra (cyanidin-3-O-glucoside and cyanidin-O-rhamnoside) and other four in R. fruticosus (cyanidin-O-hexoside, cyanidin-3-O-glucoside, cyanidin-O-pentoside, and cyanidin-3-O-dioxaloilglucoside). The developed colouring formulations revealed a good stability over time, in terms of anthocyanin concentration and colour parameters, and revealed to be safe for consumption, either concerning their low microbial load and lack of cytotoxicity. Thus, they represent a promising natural alternative to the massively used artificial colorants.

Highlights

One of the first perceptions of food is its colour, a characteristic that highly influences consumers’ choice, since it leads to the creation of an idea of the flavour, odour, and composition of the food product [1]
R. fruticosus contains as major anthocyanins cyanidin-3-glucoside, cyanidin-3-arabinoside, and cyanidin-3-galactoside, but malvidin3-glucoside, pelargonidin-3-glucoside, cyanidin-3-xyloside, cyanidin-3-rutinoside, and cyanidin3-malonylglucoside are present in smaller amounts
Morus nigra L. and Rubus fruticosus L. fruit juices were assessed for their chemical composition, namely in what concerns free sugars, organic acids, tocopherols, and anthocyanins

Summary

Introduction

One of the first perceptions of food is its colour, a characteristic that highly influences consumers’ choice, since it leads to the creation of an idea of the flavour, odour, and composition of the food product [1]. The major phenolic compounds reported are cyanidin3-glucoside, quercetin-3-rutinoside, and kaempferol-3-rutinoside, the presence of quercetin-3-glucoside, cyanidin-3-rutinoside, pelargonidine-3-glucoside, and pelargonidin3-rutinoside has been reported [8,9] These fruits are rich in fatty acids, with a prevalence of linoleic acid, sugars, mainly fructose and glucose, and organic acids, mostly citric and malic acids [3,10,11,12]. R. fruticosus contains as major anthocyanins cyanidin-3-glucoside, cyanidin-3-arabinoside, and cyanidin-3-galactoside, but malvidin3-glucoside, pelargonidin-3-glucoside, cyanidin-3-xyloside, cyanidin-3-rutinoside, and cyanidin3-malonylglucoside are present in smaller amounts As phenolic acids, it mainly contains gallic acid, protocatechuic acid, p-hydroxybenzoic acid, caffeic acid, p-coumaric acid, and ellagic acid [13]. It contains fructose and glucose, flavonoids such as kaempferol and myricetin, and in immature fruits some carotenoids such as all-trans-lutein and all-trans-zeaxanthin can be found [4,14]

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