Heat and light colour stability of beverages coloured with a natural carotene emulsion: Effect of synthetic versus natural water soluble antioxidants

Insights into the interaction mechanism of acid phosphatase from Lateolabrax japonicus livers and rosmarinic acid using multispectroscopy and molecular docking

Acid phosphatase (ACP) is a key enzyme that hydrolyzes inosinic acid. The mechanisms underlying the interaction between rosmarinic acid (RA) and ACP and the inhibition of the enzyme were investigated using inhibition kinetics, UV-visible and fluorescence spectroscopy, circular dichroism, and molecular docking. The results showed that RA was a reversible inhibitor of ACP and that the inhibition mechanism was uncompetitive. The ACP fluorescence was quenched by RA, and the quenching mode was static. The interaction of ACP with RA was driven by H bonds and van der Waals forces. The addition of RA increased the α-helix content and decreased the β-sheet, β-turn, and random coil contents in ACP, thereby altering the secondary structure of the enzyme. This study enriched our understanding of inhibitory and interaction mechanisms involving ACP and RA.

Enhancement of oral bioavailability and anti-colitis effect of luteolin-loaded polymer micelles with RA (rosmarinic acid)-SS-mPEG as carrier

OBJECTIVE

Polymer micelles were prepared (L-RSPMs) with luteolin and synthetic RA-SS-mPEG polymeric material before evaluation of their anti-inflammatory effect on 2, 4, 6-trinitro-benzene-sulfonic acid (TNBS)-induced ulcerative colitis (UC) model in rats.

METHODS

The synthetic RA-SS-mPEG was characterized with NMR spectroscopy, before preparation of luteolin-coated RA-SS-mPEG polymer micelles. The in vitro characterization and evaluation of the formulation were accomplished, couple with its pharmacokinetic parameters. The levels of PEG2, MDA, CRP and GSH, as well as concentrations of TNF-α, IL1-β, IL-6 and IL-10 in serum and colon tissue were detected via ELISA kit. The degree of colon injury and inflammation was evaluated via histopathologic examination.

RESULTS

L-RSPMs displayed small average droplet size (133.40 ± 4.52 nm), uniformly dispersed (PDI: 0.163 ± 0.011), good stability, slow release and enhanced solubility. We observed 353.28% increase in the relative bioavailability of L-RSPMs compared to free luteolin, while the half-life of the micelle was extended by 6.16h. Compared to model (M) group, luteolin (low and high doses) and L-RSPMs (low and high doses) significantly reduced levels of MDA, PEG2, CRP, TNF-α, IL-6 and IL-1β in colon tissue and serum of colitic rats but dose dependently increased IL-10 and SOD levels (p < 0.01). Histopathologic examination of colon showed that luteolin (low and high doses) and L-RSPMs (low and high doses) improved colonic inflammation in colitic rats to varying degrees compared to M group.

CONCLUSION

L-RSPMs could improve TNBS-induced colon inflammation by enhancing bioavailability, promoting antioxidant effects and regulating cytokine release, which may become a potential agent for UC treatment in clinical settings.

Evaluation of Guava Pulp Microencapsulated in Mucilage of Aloe Vera and Opuntia ficus-indica as a Natural Dye for Yogurt: Functional Characterization and Color Stability

The substitution of artificial colorants for pigments extracted from fruits is a highly desirable strategy in the food industry for the manufacture of natural, functional, and safe products. In this work, a 100% natural spray-dried (SD) microencapsulated colorant of pink guava pulp, using aloe vera (AV) or Opuntia ficus-indica (OFI) mucilage as functional encapsulating material, was prepared and evaluated as an additive into a yogurt (Y) matrix. The characterization of yogurt samples supplemented with OFI (Y-SD-OFI) and AV (Y-SD-AV) mucilage-covered guava pulp microcapsules was carried out through carotenoid quantification using UV–vis and HPLC–MS techniques, dietary fiber content, antioxidant capacity, colorimetry, and textural analysis, as well as by an evaluation of color stability after 25 days of storage at 4 °C in the dark. These physicochemical characteristics and color stability on the Y-SD-OFI and Y-SD-AV samples were compared with those of a commercial yogurt (control sample, Y-C) containing sunset yellow FCF synthetic colorant (E110). Y-SD-OFI and Y-SD-AV samples exhibited a high content of lycopene, dietary fiber, and antioxidant activity, which were absent in the control sample. Microencapsulated lycopene imparted a highly stable color to yogurt, contrary to the effect provided by the E110 dye in the control sample. The texture profile analysis revealed an increase in firmness, consistency, and cohesion in the Y-SD-OFI sample, contrary to the Y-SD-AV and Y-C samples, which was attributed to the variation in fiber concentration in the microcapsules. The incorporation of OFI and AV mucilage microparticles containing pink guava pulp into yogurt demonstrated its potential application as a functional natural colorant for dairy products.

Fabrication and characterization of a cannabidiol-loaded emulsion stabilized by a whey protein-maltodextrin conjugate and rosmarinic acid complex

A cannabidiol (CBD)-loaded oil-in-water emulsion stabilized by a whey protein (WP)-maltodextrin (MD) conjugate and rosmarinic acid (RA) complex was fabricated, and its stability characteristics were investigated under various environmental conditions. The WP-MD conjugates were formed via dry-heating. The interaction between WP and MD was assessed by browning intensity, reduced amount of free amino groups, the formation of high molecular weight components in sodium dodecyl sulfate-PAGE, and changes in secondary structure of whey proteins. The WP-MD-RA noncovalent complex was prepared and confirmed by fluorescence quenching and Fourier-transform infrared spectroscopy spectra. Emulsions stabilized by WP, WP-MD, and WP-RA were used as references to evaluate the effect of WP-MD-RA as a novel emulsifier. Results showed that WP-MD-RA was an effective emulsifier to produce fine droplets for a CBD-loaded emulsion and remarkably improved the pH and salt stabilities of emulsions in comparison with WP. An emulsion prepared with WP-MD-RA showed the highest protection of CBD against UV and heat-induced degradation among all emulsions. The ternary complex kept emulsions in small particle size during storage at 4°C. Data from the current study may offer useful information for designing emulsion-based delivery systems which can protect active substance against environmental stresses.

Heat and Light Stability of Pumpkin-Based Carotenoids in a Photosensitive Food: A Carotenoid-Coloured Beverage

This study aimed to evaluate carotenoid degradation kinetics in a beverage coloured with pumpkin juice concentrate during storage at dark and illuminated conditions at four temperatures (10, 20, 35 and 45 °C). Carotenoids were quantified by HPLC-DAD, and kinetic parameters for carotenoid degradation were estimated by one-step nonlinear regression analysis. During dark storage, degradation kinetics was modelled by fractional conversion (all-trans-β-carotene) and zero-order equations (all-trans-antheraxanthin, all-trans-lutein, all-trans-violaxanthin and all-trans-neoxanthin). Storage of samples in a climatic chamber with intense light intensity (1875–3000 lux) accelerated the carotenoid losses. At illuminated conditions, degradation followed a first-order (all-trans-lutein, all-trans-violaxanthin and all-trans-neoxanthin) and fractional conversion model (all-trans-β-carotene and all-trans-antheraxanthin). Carotenoid degradation followed an Arrhenius temperature-dependency, with Ea values lower than 50 kJ/mol. Degradation was shown to be mainly by oxidative reactions. Packaging under minimal oxygen conditions, use of antioxidants (e.g., ascorbic acid), and proper choice of light sources at retail shelves may be considered to optimize the pigment retention in a carotenoid-coloured beverage during storage.

Stability evaluation of gardenia yellow pigment in presence of different phenolic compounds

Gardenia yellow pigment (GYP) may undergo chemical degradation under different conditions resulting in color fading. This study investigated the effects of different phenolic compounds (caffeic acid, rosmarinic acid, tannic acid, epicatechin, chlorogenic acid, epigallocatechin, and epigallocatechin gallate) on the physical and chemical stability of GYP under light and different temperatures. Furthermore, food models with GYP/phenolic compounds were simulated to evaluate the GYP stability under different cooking methods. The addition of phenolic compounds, especially tannic acid, epigallocatechin gallate, epigallocatechin, and rosmarinic acid, significantly improved the GYP stability during light and thermal treatments. Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy confirmed that the formation of hydrogen bonds between GYP and selected phenolic compounds (tannic acid, epigallocatechin gallate, epigallocatechin, and rosmarinic acid), which may lead to the enhancement of GYP stability. Moreover, these selected phenolic compounds provided potent protective effects on GYP under different cooking methods.

Addition of norbixin microcapsules obtained by spray drying in an isotonic tangerine soft drink as a natural dye

Annatto seeds (Bixa orellana L.) are a natural source of norbixin, a carotenoid with antioxidant activity and an intense yellow-orange color which is a commonly used food and beverage colorant. However, it is susceptible to environmental factors such as light, oxygen, and temperature. Microencapsulation presents an alternative for improving the bioactive compound's stability. In this study, norbixin microcapsules (MCN) were added to isotonic tangerine soft drinks in a quantity not exceeding food additive regulations. The final concentration was 2.86 ± 0.02 µg norbixin/mL, and according to the CIELab system, the beverage acquired the expected orange tonality. The addition of MCN favorably affects beverage stability during storage under accelerated conditions (heat and light), and the half-life time was more significant (29.71 days) than when non-encapsulated norbixin was used (393.39 min). In conclusion, MCN should be considered as an additive with potential use in processed beverage industries instead of synthetic dyes.

Isotonic Beverage Pigmented with Water-Dispersible Emulsion from Astaxanthin Oleoresin

Astaxanthin is a powerful antioxidant, because it neutralizes free radicals and plays a vital role in the prevention of human diseases. The objective of this work was to develop an isotonic beverage (IB) of orange-red color, using an astaxanthin oleoresin emulsion (AOE) that is dispersible in water. This was carried out in order to simulate the color of commercial isotonic beverages (CIB) prepared from artificial pigments. The size of the AOE micelles ranged from 0.15 to 7.60 µm². The color difference (ΔE) was similar for the samples exposed to dark as well as light conditions. The samples subjected to light stress showed pigment degradation after seven days, followed by a decrease in the concentration of astaxanthin; whereas, the samples exposed to dark conditions remained stable for seven days and then showed a decrease in the concentration of astaxanthin (this decrease ranged from 65% to 76% when compared to the initial content) after a period of 91 days. For the astaxanthin oleoresin (AO) and AOE, the oxygen radical absorbance capacity (ORAC) values reached 5224 and 1968 µmol of trolox equivalents (TE)/100 g, respectively. When exposed to light conditions, the addition of AOE in the IB led to its rapid degradation, while it remained stable in the samples exposed to the dark conditions.

Influence of Rosemary Extract Addition in Different Phases on the Oxidation of Lutein and WPI in WPI-Stabilized Lutein Emulsions

The aim was to investigate rosemary extract with different addition methods affecting the physicochemical stability of WPI-coated lutein emulsions and examine the correlations between lutein degradation and WPI oxidation during storage. First, lutein emulsions containing different concentrations of rosemary extract in the oil phase were prepared. Second, lutein emulsions containing rosemary extract in the oil phase or water phase were studied along with the kinetic reaction of lutein degradation. Moreover, the impact of rosemary extract on the oxidation of WPI and their products was also determined. It was noticed that rosemary extract at 0.05 wt.% exhibited the best protection of lutein. According to the kinetics analysis of lutein degradation, the direct addition of rosemary extract in the oil phase was more suitable for retarding the degradation of lutein in emulsion than the addition in the aqueous phase due to it being partitioned at the interface. Meanwhile, it was revealed that the addition of rosemary extract in the water phase exhibited better inhibition of the WPI oxidation than addition in the oil phase. The understanding of the association and driving forces of rosemary extract in emulsion systems may be useful for the application of rosemary extract in multicomponent food systems.

Emulsion design for the delivery of β-carotene in complex food systems

β-Carotene has been widely investigated both in the industry and academia, due to its unique bioactive attributes as an antioxidant and pro-vitamin A. Many attempts were made to design delivery systems for β-carotene to improve its dispersant state and chemical stability, and finally to enhance the functionality. Different types of oil-in-water emulsions were proved to be effective delivery systems for lipophilic bioactive ingredients, and intensive studies were performed on β-carotene emulsions in the last decade. Emulsions are thermodynamically unstable, and emulsions with intact structures are preferable in delivering β-carotene during processing and storage. β-Carotene in emulsions with smaller particle size has poor stability, and protein-type emulsifiers and additional antioxidants are effective in protecting β-carotene from degradation. Recent development in the design of protein-polyphenol conjugates has provided a novel approach to improve the stability of β-carotene emulsions. When β-carotene is consumed, its bioaccessibility is highly influenced by the digestion of lipids, and β-carotene in smaller oil droplets containing long-chain fatty acids has a higher bioaccessibility. In order to better deliver β-carotene in complex food products, some novel emulsions with tailor-made structures have been developed, e.g., multilayer emulsions, solid lipid particles, Pickering emulsions. This review summarizes the updated understanding of emulsion-based delivery systems for β-carotene, and how emulsions can be better designed to fulfill the benefits of β-carotene in functional foods.

Influence of calcium-induced droplet heteroaggregation on the physicochemical properties of oppositely charged lactoferrin coated lutein droplets and whey protein isolate-coated DHA droplets

The influence of calcium-induced droplet heteroaggregation on the formation and physicochemical stability of mixed lutein and DHA emulsions was studied.