Thermal and Photochemical Stability of Anthocyanins from Black Carrot, Grape Juice, and Purple Sweet Potato in Model Beverages in the Presence of Ascorbic Acid

Abstract

Anthocyanins are natural dyes widely used in the food industry, but their chemical stability in beverages can be affected by the presence of additives. In the present paper, the interaction between anthocyanins and ascorbic acid (AA) is more particularly investigated. Ascorbic acid is an ubiquitous component in food products. In this study, the thermal stability at 43 °C and the photolysis stability in air and in an inert atmosphere (N 2 ) of anthocyanins extracted from black carrot (BC), grape juice (GJ), and purple sweet potato (SP) were studied in the presence and absence of ascorbic acid (in citrate buffer at pH 3). Discriminating the main environmental factors (i.e., heat and light) affecting anthocyanin stability is a key point for better understanding the degradation pathways. The stability of the anthocyanins was followed by UV−vis spectrometry. Moreover, to understand the degradation mechanisms in both the presence and absence of ascorbic acid, various techniques such as fluorescence quenching, cyclic voltammetry, and electron-spin-resonance (ESR) spectroscopy were also used to furnish a full coherent picture of the chemical mechanisms associated with the anthocyanin degradation. In addition, molecular orbitals and bond-dissociation energies (BDE) were calculated to extend the investigation. Moreover, the effects of some supplementary stabilizers (chlorogenic acid, sinapic acid, tannic acid, fumaric acid, β-carotene, isoquercitrin, myricitrin, green coffee bean extract, and rosemary extract) and sugars (sucrose, fructose, and glucose) on anthocyanins stability in the presence of ascorbic acid were examined.

Photopolymerization and 3D/4D applications using newly developed dyes: Search around the natural chalcone scaffold in photoinitiating systems

“…In this context, these natural dyes have attracted a great deal of interest in various research fields [12][13][14]. The natural dyes can easily initiate an electron transition from the ground state to the excited state after absorbing the appropriate light and thus generate the active species (e.g.…”

The Effect of Plant Additives on the Stability of Polyphenols in Cloudy and Clarified Juices from Black Chokeberry (Aronia melanocarpa)

“…Otherwise, inadequate combinations may provide little or no protection to anthocyanins. Gérard and co-workers [61] studied antioxidants in the form of seven pure compounds and two extracts with strong antioxidative effect, i.e., green coffee bean extract and rosemary extract. The anthocyanin extracts of black carrot, grape juice and purple sweet potato to which 200 mg/L ascorbic acid was added were very slightly stabilised only by chlorogenic acid, sinapic acid, fumaric acid, and β-carotene.…”

Grown to be Blue—Antioxidant Properties and Health Effects of Colored Vegetables. Part I: Root Vegetables

“…Acylated anthocyanins are responsible for the intense color of purple-fleshed sweet potatoes [66,130], which renders them good candidates sources for natural colorants with practical application in the food industry [131]. Moreover, peels are also a good source of natural pigments since they contain significant amounts of anthocyanins, and the exploitation of this by-product for obtaining coloring agents would increase the added value of the sweet-potato crop [74].…”

“…Black carrots contain high amounts of mono-acylated anthocyanins which are less prone to thermal degradation, while they can retain their color at various pH values and storage conditions [31,32,34]. These functional and structural characteristics of colored carrot pigments make them good candidates for the extraction of natural colorant agents with practical applications in the food industry, especially in food products with low pH, in beverages and confectioneries [40,131,177]. However, despite their stability under various conditions, Espinosa-Acosta et al [82] did not suggest their use in food models such as yoghurt and jelly, except for the case of ethanolic extracts of black carrots, which could be incorporated into jellies to increase the antioxidant activity of the final product.…”