Instantaneous interaction of mucin with pectin- and carrageenan-coated nanoemulsions.

The efficiency of drug delivery and sensory perception is intertwined with mucoadhesive systems. The physiochemical characteristics of mucus induce flocculation of emulsion droplets, which could significantly influence their sensory perception. In this study, we investigated the interactions between pectin- and carrageenan-coated nanoemulsions with mucin. The size and ζ-potential changes in the nanoemulsions were investigated at pHs 3.0-5.0. The results showed no significant differences (p > 0.05) in size without the addition of gums; however, the ζ-potential decreases from 2.92 mV to -2.51 mV as pH increased. The stability of nanoemulsions over the extended time (15 days) and at elevated temperature (60 °C) resulted in minimal degree of phase separation observed. The mucin particle size method was employed to characterize mucin-nanoemulsion interactions. Results confirmed that mucin-emulsion complexes were formed instantaneously mostly due to electrostatic interactions. The contact angle analysis and UV-Vis spectroscopy confirmed contribution of wetting and absorption mechanisms in the mucin interactions.

Ascorbic Acid Derivatives as Potential Substitutes for Ascorbic Acid To Reduce Color Degradation of Drinks Containing Ascorbic Acid and Anthocyanins from Natural Extracts.

Ascorbic acid is widely used in the food industry as a source of vitamin C or as antioxidant. However, it degrades quickly in beverages at acidic pH and can accelerate the degradation of anthocyanins, natural dyes used in beverages, leading to a loss of color. In this work, we investigated the possibility to replace ascorbic acid by ascorbic acid derivatives to prevent its degradation effect on anthocyanins from natural extracts (black carrot, grape juice, and purple sweet potato). For this, the thermal and photolytic stabilities under air and under N2 of ascorbic acid (as reference) and of some ascorbic acid derivatives (3-O-ethyl-l-ascorbic acid, 2-O-α-d-glucopyranosyl-l-ascorbic acid, l-ascorbic acid 2-phosphate sesquimagnesium salt hydrate, l-ascorbyl 2,6-dibutyrate, glyceryl ascorbate, (+)-5,6-O-isopropylidene-l-ascorbic acid), soluble in aqueous model beverages, were studied alone and in the presence of anthocyanins from the natural extracts in citrate buffer at pH 3. The stability was followed by UV-visible spectrometry. To extend the investigation, some properties of the ascorbic acid derivatives (pKa, oxidation potential, bond dissociation energy, ionization potential) were also determined. Moreover, the addition of chlorogenic acid was examined to further stabilize the mixture of anthocyanins with 2-O-α-d-glucopyranosyl-l-ascorbic acid, a promising ascorbic acid derivative.

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

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 (N2) 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, ß-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.

Stabilization of natural colors and nutraceuticals: Inhibition of anthocyanin degradation in model beverages using polyphenols.

Anthocyanins are widely used as natural colorants in foods, but they are highly susceptible to chemical degradation during storage leading to color fading. This study examined the potential of natural quillaja saponin and polyphenols (vanillin, epigallocatechin gallate, green tea extract, and protocatechualdehyde) at inhibiting color fading of anthocyanins in model beverages. The purple carrot anthocyanin (0.025%) in model beverages (citric acid, pH 3.0) containing l-ascorbic acid (0.050%) degraded with a first-order reaction rate during storage (40°C/7days in light). The addition of polyphenols (0.2%) delayed color fading, with the most notable improvement observed with green tea extract addition. The half-life for anthocyanin color fading increased from 2.9 to 6.7days with green tea extract. Fluorescence quenching measurements showed that the green tea extract contained components that interacted with anthocyanins probably through hydrophobic interactions. Overall, this study provides valuable information about enhancing the stability of anthocyanins in beverage systems using polyphenols.