Food colorants: Challenges, opportunities and current desires of agro-industries to ensure consumer expectations and regulatory practices

Eco-Toxicological and Kinetic Evaluation of TiO2 and ZnO Nanophotocatalysts in Degradation of Organic Dye

In this study, the photocatalytic degradation of azo dye “Food Black 1” (FB1) was investigated using TiO2 and ZnO nanoparticles under ultraviolet (UV) light. The performances of the two photocatalysts were evaluated in terms of key parameters (e.g., decolorization, dearomatization, mineralization, and detoxification of dye) in relation to variables including pre-adsorption period, pH, and temperature. Under acidic conditions (pH 5), the ZnO catalyst underwent photocorrosion to increase the concentration of zinc ions in the system, thereby increasing the toxic properties of the treated effluent. In contrast, TiO2 efficiently catalyzed the degradation of the dye at pH 5 following the Langmuir–Hinshelwood (L–H) kinetic model. The overall results of this study indicate that the decolorization rate of TiO2 on the target dye was far superior to ZnO (i.e., by 1.5 times) at optimum catalyst loading under UV light.

Organoleptic excipients used in pediatric antibiotics

Taste is a crucial factor that determines the palatability of the oral dosage form and patient compliance.

OBJECTIVE

The aim of this work was to evaluate the organoleptic excipients in oral antibiotics for pediatric use marketed in Brazil.

METHODS

The information was obtained from the GuidetoPharmacy, a reference for the pharmaceutical trade. The analysis included dosage forms for oral administration and drugs and their combination with antibacterial action. After this survey, we identified the constitution of the flavoring, sweetening, and coloring agents of each medicine. The results are presented in a descriptive form.

RESULTS

Twelve drugs or associations are distributed in 70medicines. Oral suspension was the most common pharmaceutical dosage form. Sweeteners were sucrose, sodium saccharin, and sodium cyclamate. All the coloring agents observed are synthetic and the most frequent ones were yellow twilight no. 6, yellow tartrazine no. 5, and red ponceau 4R. The presence of two or more types of flavorings per medicine was observed.

CONCLUSION

Antibacterials use coloring agents, flavorings, and sweeteners to facilitate the administration of medicines for children, using up to six different substances per formulation. No natural coloring agent was observed, demonstrating an issue to be explored in the future. It is important to note that, although necessary, these excipients are responsible for a high incidence of allergic reactions in children.

Prospective Study of Microbial Colorants under the Focus of Patent Documents

BACKGROUND

Colorant-producing microorganisms are quite common in nature. These biomolecules present many biological activities such as antitumoral, antimicrobial and antioxidant, in addition to the various nuances of color, making them of special technological importance to the industrial sectors.

OBJECTIVE

This study aims to conduct a technological mapping in the patent, at European patent Office (EPO), in order to evaluate the global panorama of the use of microbial colorants.

METHODS

The experimental design was acquired by the keyword-driven approach through the advanced search in the Espacenet database European Patent Office (EPO). The keywords selected were bacteria or fungi* or yeast or algae or microorganism* but not plant* and pigment* or color* or colorant* or dye* and the International Patent Classification code, C09B61, for prospecting of interest.

RESULTS

There has been a linear increase in patents developed in the last 20 years, with Japan as the largest depositor in the area. The companies Dainippon Ink and Chemicals and Ajinomoto, both being Japanese, are the largest depositors with 20% of all patents. Among the microorganisms, the filamentous fungi appeared in the first place with 32% of documents and the fungi of the genus Monascus were the most frequently used.

CONCLUSION

The use of microbial colorants has been growing among industries, mainly in food sectors, due to the growing demand for products of natural origin. Thus, the increase in research and technological development in the area of microbial colorants can become an economically viable and promising strategy for the various industrial sectors.

Anthocyanin Profile of Elderberry Juice: A Natural-Based Bioactive Colouring Ingredient with Potential Food Application

Elderberry (Sambucus nigra L.) is a widely disseminated plant that produces bright black berries containing high quantities of anthocyanins, acknowledged for their bioactivity and dye capacity. Besides other applications, anthocyanins might be employed as natural colouring agents to reduce/eliminate the use of artificial dyes, while providing positive effects on consumers' health. Herein, the anthocyanins profile of elderberry juice was characterised by HPLC-DAD-ESI/MSn. In addition, its antioxidant capacity and cytotoxicity were also evaluated. As a proof-of-concept of its colouring capacity, elderberry juice was added (different percentages) to a highly appreciated and consumed pastry product (croissant) and compared with a commercial dye (black carrot). In general, the nutritional properties of control and coloured croissants were similar, despite some individual differences in sugars and fatty acids. In turn, the appearance obtained with elderberry juice incorporation might be considered innovative, besides partially maintaining the anthocyanins content of fresh juice and showing considerable antioxidant activity.

An Overview of Carotenoids, Apocarotenoids, and Vitamin A in Agro-Food, Nutrition, Health, and Disease

Carotenoids are fascinating compounds that can be converted into many others, including retinoids that also play key roles in many processes. Although carotenoids are largely known in the context of food science, nutrition, and health as natural colorants and precursors of vitamin A (VA), evidence has accumulated that even those that cannot be converted to VA may be involved in health-promoting biological actions. It is not surprising that carotenoids (most notably lutein) are among the bioactives for which the need to establish recommended dietary intakes have been recently discussed. In this review, the importance of carotenoids (including apocarotenoids) and key derivatives (retinoids with VA activity) in agro-food with relevance to health is summarized. Furthermore, the European Network to Advance Carotenoid Research and Applications in Agro-Food and Health (EUROCAROTEN) is introduced. EUROCAROTEN originated from the Ibero-American Network for the Study of Carotenoids as Functional Food Ingredients (IBERCAROT).

Rubus ulmifolius Schott as a Novel Source of Food Colorant: Extraction Optimization of Coloring Pigments and Incorporation in a Bakery Product

(1) Background: Color has been considered to be the flashiest attribute of foodstuffs and researchers have shown a great interest in the extraction of pigmented compounds from vegetal products, with the purpose to provide alternative counterparts to the food industry; (2) Methods: This study aimed to explore Rubus ulmifolius Schott fruits as a potential source of anthocyanins, optimizing the extraction method, evaluating the bioactivity and incorporating the rich extract into a bakery food product; (3) Results: After the extraction optimization, results showed R. ulmifolius fruits to be a great source of anthocyanins, obtaining an amount of 33.58 mg AT/g E, with an extraction yield of 62.08%. The rich anthocyanin extract showed antitumor and antimicrobial potential in some tumor cell lines and strains, respectively, as well as the absence of toxicity; (4) Conclusions: The extract when incorporated in a bakery product showed a good coloring capacity, maintaining the nutritional value, revealing its use to be a great approach for replacing artificial colorants.

Skin Carotenoids in Public Health and Nutricosmetics: The Emerging Roles and Applications of the UV Radiation-Absorbing Colourless Carotenoids Phytoene and Phytofluene

In this work, the importance of dietary carotenoids in skin health and appearance is comprehensively reviewed and discussed. References are made to their applications in health-promoting and nutricosmetic products and the important public health implications that can be derived. Attention is focused on the colourless UV radiation (UVR)-absorbing dietary carotenoids phytoene and phytofluene, which are attracting increased interest in food science and technology, nutrition, health and cosmetics. These compounds are major dietary carotenoids, readily bioavailable, and have been shown to be involved in several health-promoting actions, as pinpointed in recent reviews. The growing evidence that these unique UVR-absorbing carotenoids with distinctive structures, properties (light absorption, susceptibility to oxidation, rigidity, tendency to aggregation, or even fluorescence, in the case of phytofluene) and activities can be beneficial in these contexts is highlighted. Additionally, the recommendation that the levels of these carotenoids are considered in properly assessing skin carotenoid status is made.

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, 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.

Short-Term Bixin Supplementation of Healthy Subjects Decreases the Susceptibility of LDL to Cu2+-Induced Oxidation Ex Vivo

Lycopene-based medications and supplements have been developed to prevent atherosclerosis, primarily because of their ability to decrease low-density lipoprotein (LDL) oxidation. Bixin and norbixin are carotenoids found in the seeds of annatto (Bixa orellana) and are colorants widely used by the food industry. Some studies have already demonstrated that these compounds have antioxidant and antiatherogenic potential in vitro and in animal models, but there is no evidence supporting the effects of their long-term or short-term consumption by humans. The aim of this study was to evaluate the effects of short-term intake of annatto carotenoids on biochemical and oxidative stress biomarkers as well as on the susceptibility of LDL oxidation in healthy individuals, using lycopene as a positive control. The effect of daily supplementation (0.05 mg/kg of body weight (b.w.)) with bixin, norbixin, lycopene, or placebo for 7 days was evaluated in a randomized, controlled crossover study in 16 healthy volunteers (8 men and 8 women). The susceptibility of LDL to Cu²⁺-induced oxidation ex vivo, biochemical parameters, and oxidative stress biomarkers were evaluated. No treatment affected biochemical parameters or most oxidative stress biomarkers. However, bixin reduced the oxidation rate of the LDL lipid moiety (−275%, p < 0.1) and nitric oxide metabolites (NOx) (−460%, p < 0.1), compared to the placebo group. Moreover, we observed that the changes in these parameters were positively associated, supporting the hypothesis that bixin decreases the susceptibility of LDL to Cu²⁺-induced oxidation by decreasing NOx levels, probably by downregulating the inducible nitric oxide synthase.

Enhancing the antimicrobial and antifungal activities of a coloring extract agent rich in betacyanins obtained from Gomphrena globosa L. flowers

Although less explored than beetroot (Beta vulgaris L.), the flowers of Gomphrena globosa L. are a very suitable source of betacyanins with strong pigmentation features, together with many other desirable bioactive properties. Thus, the aim of this study was to enhance the antimicrobial and antifungal activities of a pigmented extract obtained from G. globosa flowers by ultrasound assisted extraction (UAE). The procedure was supported with the application of the response surface methodology, a robust optimization technique that allows to study jointly the effects of several variables and responses. To enhance the antimicrobial (Bacillus cereus, Listeria monocytogenes, Escherichia coli and Salmonella typhimurium) and antifungal (Aspergillus flavus, Aspergillus niger, Penicillium ochrochloron and Penicillium verrucosum) activities, the responses were evaluated in terms of the concentrations needed to obtain minimum inhibitory (MIC), minimum bactericidal (MBC) and minimum fungicidal (MFC) concentrations. It was found that the optimal UAE conditions were 10.8 min, 410.5 W, 57.8% of ethanol, and 5 g L-1 of the solid-liquid ratio providing the following response values: (1) from the studied species of bacteria, the MIC ranged from ∼0.15 to 0.35 g L-1 and the MBC ranges were ∼0.30 to 0.65 g L-1; and (2) from the studied fungus species, the MIC ranged from ∼0.20 to 0.30 g L-1 and the MFC ranges were ∼0.40 to 0.65 g L-1. The antibacterial activity dose levels were lower than the antifungal ones. In conclusion, the results obtained in this study highlight extracts from G. globosa flowers as natural sources of betacyanins with application as food colorants with important antimicrobial and antifungal activities.

Pigments and vitamins from plants as functional ingredients: Current trends and perspectives

The food manufacturing industry has increasingly focused in the development of wholesome and safer products, including certified labeled "super foods," "healthy foods" and "functional foods," which are currently under great demand worldwide. Plant pigments and vitamins are amidst the most common additives incorporated to foodstuff, not only for improving their nutritional status but also for coloration, preservation, and even therapeutic purposes. The recovery of pigments from agro industrial wastes using green emerging approaches is a current trend and clearly the best alternative to ensure their sustainable obtainment and make these ingredients more popular, although still full of challenging aspects. Stability and bioavailability limitations of these active molecules in food matrices have been increasingly studied, and a number of methods have been proposed to minimize these issues, among which the incorporation of a co-pigment, exclusion of O₂ during processing and storage, and above all, microencapsulation and nanoencapsulation techniques. The most recent advances and challenges in the application of natural pigments and vitamins in functional foods, considering only reports of the last 5 years, were the focus of this chapter.

Optimization of the Extraction Process to Obtain a Colorant Ingredient from Leaves of Ocimum basilicum var. purpurascens

Heat-Assisted Extraction (HAE) was used for the optimized production of an extract rich in anthocyanin compounds from Ocimum basilicum var. purpurascens leaves. The optimization was performed using the response surface methodology employing a central composite experimental design with five-levels for each of the assessed variables. The independent variables studied were the extraction time (t, 20–120 min), temperature (T, 25–85 °C), and solvent (S, 0–100% of ethanol, v/v). Anthocyanin compounds were analysed by HPLC-DAD-ESI/MS and the extraction yields were used as response variables. Theoretical models were developed for the obtained experimental data, then the models were validated by a selected number of statistical tests, and finally, those models were used in the prediction and optimization steps. The optimal HAE conditions for the extraction of anthocyanin compounds were: t = 65.37 ± 3.62 min, T = 85.00 ± 1.17 °C and S = 62.50 ± 4.24%, and originated 114.74 ± 0.58 TA mg/g of extract. This study highlighted the red rubin basil leaves as a promising natural matrix to extract pigmented compounds, using green solvents and reduced extraction times. The extract rich in anthocyanins also showed antimicrobial and anti-proliferative properties against four human tumor cell lines, without any toxicity on a primary porcine liver cell line.

Quality and Nutritional/Textural Properties of Durum Wheat Pasta Enriched with Cricket Powder

Cricket powder (CP) contains significant amounts of protein, fat (including unsaturated fatty acids), and fiber, as well as vitamins and minerals. The high nutritional value and low price make it an interesting addition to food production. This paper is a report on the results of the addition of cricket powder to pasta. Three levels of durum semolina replacement were chosen: 5%, 10%, and 15%. The obtained products were analyzed for their nutritional composition, cooking and textural properties, and color, as well as consumer acceptance. The results indicate that the addition of CP influenced the cooking weight and cooking loss (reducing losses and water absorption), as well as the color of the pasta, reducing its lightness and shifting color balances to blue and red. The firmness of pasta was also influenced. The firmness was strengthened by addition of CP. Principal components analysis indicated that the flavor change had the most pronounced effect on consumer acceptance. Nevertheless, sensory evaluation proved that protein-enriched pasta produced with CP has consumer acceptance comparable with that of conventional products.

Green Natural Colorants

Although there is no legal and clear definition of the term “natural food colorant”, the market trends, and consequently industrial and commercial interest, have turned to foods with added natural pigments. This progressive substitution of artificial colorants has faced chemical complications with some colors, with a lack of stable green hues being one of them. Several strategies have been applied for green color stabilization in processed foods, from the formation of metallochlorophylls to the microencapsulation of green pigments. However, at present, the utilization of green coloring foodstuffs, which are considered an ingredient in the EU, seems to be the more successful solution for the market. Besides those topics, the present review aims to clarify the current confusion between the different chlorophyll compounds that form part of the authorized green food colorants. In this sense, legislations from different countries are compared. Finally, and in line with current concerns, the knowledge gathered so far in relation to the absorption, distribution, metabolism and excretion of all green natural food colorants is reviewed.

Lemon yellow #15 a new highly stable, water soluble food colorant from the peel of Citrus limon

To provide stable and low-cost naturally derived yellow pigments, a variety of food byproducts were evaluated and the constituents of lemon peel have emerged yielding a highly promising natural product with applications as a food dye. Here we report a new, highly stable and water soluble food dye called yellow #15 from the ethanol extract of the zest of Citrus limon. The structure of lemon yellow #15 was carefully assigned on the basis of spectroscopic data, including 1D and 2D NMR spectroscopy, and the absolute configuration was established by comparison of the experimental CD with calculated electronic circular dichroism (ECD) spectral data. CIELAB values and Delta CIELAB were measured and revealed this new water-soluble pigment has superior light stability relative to other natural products used as food dyes.

Development of Aurantiochytrium limacinum SR21 cultivation using salt-rich waste feedstock for docosahexaenoic acid production and application of natural colourant in food product

Microalgae biorefinery is presently receiving a lot of attention as driven by its production of high value-added products. In this study, an oleaginous microalga Aurantiochytrium limacinum SR21 was cultured for docosahexaenoic acid (DHA) production using 20% (w/v) of K₂HPO₄-waste feedstock to replace 0.005% (w/v) of KH₂PO₄ in the flask culture. DHA is an essential nutrient for human's brain functionalities. Collectively, the K₂HPO₄-waste feedstock with working concentration of 0.005% (w/v) in the cultivation prompted a higher lipid content (8.29%) and DHA production (128.81 mg.L^-1). Moreover, natural plant pigment products containing stabilised betacyanins were utilised as natural red colourants for hard candy production. This study develops microalgal cultivation using salt-rich waste feedstock for a higher lipid and DHA content as well as application of natural colouring agents in food products.

Production and extraction of carotenoids produced by microorganisms

Carotenoids are a group of isoprenoid pigments naturally synthesized by plants and microorganisms, which are applied industrially in food, cosmetic, and pharmaceutical product formulations. In addition to their use as coloring agents, carotenoids have been proposed as health additives, being able to prevent cancer, macular degradation, and cataracts. Moreover, carotenoids may also protect cells against oxidative damage, acting as an antioxidant agent. Considering the interest in greener and sustainable industrial processing, the search for natural carotenoids has increased over the last few decades. In particular, it has been suggested that the use of bioprocessing technologies can improve carotenoid production yields or, as a minimum, increase the efficiency of currently used production processes. Thus, this review provides a short but comprehensive overview of the recent biotechnological developments in carotenoid production using microorganisms. The hot topics in the field are properly addressed, from carotenoid biosynthesis to the current technologies involved in their extraction, and even highlighting the recent advances in the marketing and application of "microbial" carotenoids. It is expected that this review will improve the knowledge and understanding of the most appropriate and economic strategies for a biotechnological production of carotenoids.

A Comparative Study of Advanced Stationary Phases for Fast Liquid Chromatography Separation of Synthetic Food Colorants

Food analysis demands fast methods for routine control and high throughput of samples. Chromatographic separation enables simultaneous determination of numerous compounds in complex matrices, several approaches increasing separation efficiency and speed of analysis were involved. In this work, modern types of column with monolithic rod or superficially porous particles were employed and compared for determination of eight synthetic food dyes, their chromatographic performance was evaluated. During method optimization, cyano stationary phase Chromolith Performance CN 100 × 4.6 mm and Ascentis Express ES-CN 100 × 4.6 mm, 5 µm were selected for the separation of polar colorants. The separation was performed by gradient elution of acetonitrile/methanol and 2% water solution of ammonium acetate at flow rate 2.0 mL min-1. Mobile phase composition and the gradients were optimized in order to enable efficient separation on both columns. The method using fused-core particle column provided higher separation efficiency, narrow peaks of analytes resulted in increased peak capacity and shortening of analysis time. After the validation, the method was applied for analysis of coloured beers, soft drinks and candies.

Food Byproducts as Sustainable Ingredients for Innovative and Healthy Dairy Foods

The valorization of food wastes and byproducts has become a major subject of research to improve the sustainability of the food chain. This narrative review provides an overview of the current trends in the use of food byproducts in the development of dairy foods. We revised the latest data on food loss generation, the group of byproducts most used as ingredients in dairy product development, and their function within the food matrix. We also address the challenges associated with the sensory properties of the new products including ingredients obtained from byproducts, and consumers' attitudes towards these sustainable novel dairy foods. Overall, 50 studies supported the tremendous potential of the application of food byproducts (mainly those from plant-origin) in dairy foods as ingredients. There are promising results for their utilization as food additives for technological purposes, and as sources of bioactive compounds to enhance the health-promoting properties of dairy products. However, food technologists, nutritionists and sensory scientists should work together to face the challenge of improving the palatability and consumer acceptance of these novel and sustainable dairy foods.

Optimization of heat- and ultrasound-assisted extraction of anthocyanins from Hibiscus sabdariffa calyces for natural food colorants

Heat- and ultrasound-assisted extraction methods were applied to recover anthocyanins from Hibiscus sabdariffa calyces. The extraction variables, time (t), ethanol proportion (S), and temperature (T) or ultrasonic power (P), were combined in a 5-level experimental design and analysed by response surface methodology for process optimization. The delphinidin-3-O-sambubioside (C1) and cyanidin-3-O-sambubioside (C2) levels were monitored by LC-DAD-ESI/MSⁿ and used as response criteria. The developed models were successfully fitted to the experimental data and used to determine optimal extraction conditions. UAE was the most efficient method yielding 51.76 mg C1 + C2/g R under optimal conditions (t = 26.1 min, P = 296.6 W and S = 39.1% ethanol, v/v). The dose-response effects of the solid/liquid ratio on the extraction rate were also determined. The anthocyanin levels herein reported are higher than those found in the literature, which support the potential use of H. sabdariffa as a sustainable source of natural colorants with application in different industrial sectors.

Inhibitory Effect of Opuntia humifusa Fruit Water Extract on Solar Ultraviolet-Induced MMP-1 Expression

Opuntia humifusa is a type of cactus whose fruits have been used in folk medicine for the treatment of several diseases. In the present study, we aimed to determine whether O. humifusa fruit water extract (OHE) has inhibitory effects against solar ultraviolet (sUV)-induced matrix metalloproteinase-1 (MMP-1) expression. In ex vivo human skin, we found that OHE suppressed sUV radiation-induced MMP-1 expression. The inhibitory effect of OHE was confirmed in human dermal fibroblasts. OHE treatment reduced sUV-induced MMP-1 expression by suppressing reactive oxygen species (ROS) generation and phosphorylation of c-Jun, a component of transcription factor activator protein 1 (AP-1). On the other hand, OHE recovered the tissue inhibitor of matrix metalloproteinase 1 (TIMP-1) and type 1 collagen production attenuated by sUV. As upstream signaling pathways for AP-1, MKK4-JNK, MEK-ERK, and MKK3/6-p38 phosphorylation were downregulated by OHE treatment. In addition, OHE exhibited DPPH radical scavenging activity. These findings demonstrate that OHE has a preventive effect against sUV-induced skin damage via suppression of pathways triggered by ROS.

Nanoencapsulation improved water solubility and color stability of carotenoids extracted from Cantaloupe melon (Cucumis melo L.)

Cantaloupe melon carotenoids were encapsulated in porcine gelatin, whey protein isolate and concentrate by emulsification O/W to evaluate which agent could promote an increase in water solubility, and color stability in yogurt. The average particle size obtained was 59.3 (2.60) nm-161.0 (27.30) nm. Encapsulated crude extract in porcine gelatin presented the smallest size and polydispersity index [0.4 (0.04)], and showed sphericity, smooth surface and low agglomeration in SEM. These results associated to the good chemical interaction between the raw materials shown by FTIR, justify the increase in water solubility [0.072 (0.007) mg.mL^-1] compared to the crude extract [0.026 (0.003) mg.mL^-1]. The yogurt added with this nanoencapsulate remained stable for 60 days, unlike the crude extract. The results show that the nanoencapsulation using gelatin increased water solubility and the potential of application of melon carotenoids in food as natural dyes.

Engineering de novo anthocyanin production in Saccharomyces cerevisiae

BACKGROUND

Anthocyanins are polyphenolic pigments which provide pink to blue colours in fruits and flowers. There is an increasing demand for anthocyanins, as food colorants and as health-promoting substances. Plant production of anthocyanins is often seasonal and cannot always meet demand due to low productivity and the complexity of the plant extracts. Therefore, a system of on-demand supply is useful. While a number of other (simpler) plant polyphenols have been successfully produced in the yeast Saccharomyces cerevisiae, production of anthocyanins has not yet been reported.

RESULTS

Saccharomyces cerevisiae was engineered to produce pelargonidin 3-O-glucoside starting from glucose. Specific anthocyanin biosynthetic genes from Arabidopsis thaliana and Gerbera hybrida were introduced in a S. cerevisiae strain producing naringenin, the flavonoid precursor of anthocyanins. Upon culturing, pelargonidin and its 3-O-glucoside were detected inside the yeast cells, albeit at low concentrations. A number of related intermediates and side-products were much more abundant and were secreted into the culture medium. To optimize titers of pelargonidin 3-O-glucoside further, biosynthetic genes were stably integrated into the yeast genome, and formation of a major side-product, phloretic acid, was prevented by engineering the yeast chassis. Further engineering, by removing two glucosidases which are known to degrade pelargonidin 3-O-glucoside, did not result in higher yields of glycosylated pelargonidin. In aerated, pH controlled batch reactors, intracellular pelargonidin accumulation reached 0.01 µmol/gCDW, while kaempferol and dihydrokaempferol were effectively exported to reach extracellular concentration of 20 µM [5 mg/L] and 150 µM [44 mg/L], respectively.

CONCLUSION

The results reported in this study demonstrate the proof-of-concept that S. cerevisiae is capable of de novo production of the anthocyanin pelargonidin 3-O-glucoside. Furthermore, while current conversion efficiencies are low, a number of clear bottlenecks have already been identified which, when overcome, have huge potential to enhance anthocyanin production efficiency. These results bode very well for the development of fermentation-based production systems for specific and individual anthocyanin molecules. Such systems have both great scientific value for identifying and characterising anthocyanin decorating enzymes as well as significant commercial potential for the production of, on-demand, pure bioactive compounds to be used in the food, health and even pharma industries.

Bioactive evaluation and application of different formulations of the natural colorant curcumin (E100) in a hydrophilic matrix (yogurt)

Curcumin (E100) is a natural colorant that, besides conferring color, has bioactivity, serving as an alternative to some artificial colorants. As a hydrophobic colorant, its modification/compatibilization with the aqueous medium is required to improve stability and enable its application in hydrophilic food matrices. Herein, different formulations of curcumin (curcumin powder: PC, water-dispersible curcumin: DC: and nanoencapsulated curcumin: NC) were evaluated as yogurt colorants. PC showed the strongest bioactivity in all assays (EC₅₀ values: 63 ± 2 to 7.9 ± 0.1 μg.mL^-1; GI₅₀ values: 48 ± 1 to 17 ± 1 μg.mL^-1 and MIC values: 0.0625 to 0.5 mg.mL^-1), which might indicate that DC and NC reduce the short-term accessibility to curcumin. The tested curcumin formulations produced yogurts with different appearance, specifically associated with their color parameters, besides presenting slight changes in nutritional composition and free sugars and fatty acids profiles. The water compatible formulations (DC and NC) showed advantages over hydrophobic (PC) having a wider industrial utilization.

Investigating the Interaction of Ascorbic Acid with Anthocyanins and Pyranoanthocyanins

Juices colored by anthocyanins experience color loss related to fortification with ascorbic acid (AA), thought to be the result of condensation at Carbon-4 of anthocyanins. To further understand this mechanism, pyranoanthocyanins, having a fourth-ring covalently occupying Carbon-4, were synthesized to compare its reactivity with AA against that of anthocyanins. Pyranoanthocyanins were synthesized by combining chokeberry anthocyanins with pyruvic acid. AA (250–1000 mg/L) was added to either chokeberry extract, cyanidin-3-galactoside, or 5-Carboxypyranocyanidin-3-galactoside. Samples were stored in the dark for 5 days at 25 °C and spectra (380–700 nm), color (CIE-L*c*h*), and composition changes (HPLC-MS/MS) were monitored. Extensive bleaching occurred for cyanidin-3-galactoside and chokeberry colored solutions, with a decrease in half-lives from 22.8 to 0.3 days for Cyanidin-3-galactoside when 1000 mg/L AA was added. 5-Carboxypyranocyanidin-3-galactoside solution better maintained color with limited loss in absorbance, due to the formation of colored degradation products (λ_vis-max = 477 to 487 nm), and half-life decrease from 40.8 to 2.7 days, an 8–13-fold improvement compared to anthocyanins. This suggested alternative sites of reactivity with AA. Carbon-4 may be the preferred site for AA-pigment interactions, but it was not the only location. With Carbon-4 blocked, 5-Carboxypyranocyanidin-3-galactoside reacted with AA to form new pigments and reduce bleaching.

Antimicrobial evaluation of red, phytoalexin-rich sorghum food biocolorant

Sorghum (Sorghum bicolor) extract is traditionally used as red biocolorant in West Africa to colour foods, among which wagashi, a soft cheese. This biocolorant is a source of the phytoalexin apigeninidin and phenolic acids, and users claim that it has preservative effects next to its colouring properties. If such a claim can be scientifically substantiated, it adds a valuable functional property to this natural red colorant, thereby increasing its potential applications in the food industry. Hence, the present study evaluated the antimicrobial properties of dye sorghum extracts using challenge tests in broth and wagashi as a model of a popular food application. The alkaline extract and hot aqueous extract were used for dyeing wagashi by 87.7% and 12.3% of the traders, respectively. The dyeing procedure is perceived as a preservation strategy, and is also a means to maximise the revenues. However, results demonstrated that the application of sorghum biocolorant on wagashi had no inhibitory effect on the growth of fungi (Penicillium chrysogenum, Cladosporium macrocarpum) and Escherichia coli O157:H7. Furthermore, sorghum biocolorant in broth had no effect on growth of Listeria monocytogenes and Escherichia coli O157:H7. Consequently, the commonly used extracts for colouring soft West-African cheese did not show a preservative effect. In addition, dyeing did not affect the physico-chemical properties of wagashi. Still, the red colour hampered visual detection of microbial growth, thus clarifying the preservative effect reported by users.

A Metabolomic Overview of Follicular Fluid in Cows

Follicular fluid (FF) protects the oocyte against proteolysis and extrusion during ovulation, providing an appropriate microenvironment that favors proper embryonic development; thereby, FF plays a key role in embryo quality. Being directly related to cattle breeding, studying FF is extremely important in livestock science to measure cattle fertility. This may eventually help to assess the quality of both meat and milk, products widely consumed worldwide. There is an important commercial interest in the evaluation and characterization of compounds present in the FF of livestock that present greater likelihood of pregnancy. Mass spectrometry is a great ally for this type of analysis and can provide quick and efficient screening for molecular markers in biological samples. The present study demonstrated the potential of high-resolution mass spectrometry in analyzing FF samples from two distinct groups of Nellore cows (Bos indicus): high and low fertility, as determined by the number of oocytes produced. We were able to delineate markers of interest for each group, which may ultimately be related to biochemical pathways that lead to higher or lower reproductive performance.