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The aim of this study was to assess the performance and stability of betacyanin compounds present in enriched extracts of red-fleshed pitaya peels ( Hylocereus costaricensis ) and the flowers of Amaranthus caudatus ; they were evaluated as natural food colorants in tagliatelle pasta and meringue cookies. The recovered natural extracts showed promising stability, maintaining a deep pink color over a storage time of 14 days, without deeply changing the chemical composition. A number of factors were assessed, including the microbial load, texture, color, nutritional value, and contents of organic acids, fatty acids, and even free sugars of the products. Some significant interactions between the type of colorant and storage time contributed to the changes in some analyzed parameters, as can be observed from the results for organic and fatty acids in the tagliatelle pasta and meringue cookies. Another significant achievement was the reduction in the microbial load during the storage time, which strengthens the antibacterial power of these natural extracts.

Hylocereus costaricensis peel contains large amounts of betacyanins and can be exploited as a source of natural colorants. This work aimed the chemical characterization and evaluation of bioactive properties of this by-product and the optimization of the ultrasound-assisted extraction (UAE) of betacyanins using the response surface methodology (RSM). Oxalic and malic acids and traces of fumaric acid were detected, as well as the four tocopherol isoforms, predominantly γ-tocopherol. Four betacyanins were identified and used as response criteria for UAE optimization, namely phyllocactin, isobetanin, isophyllocactin, and betanin. Sample processing at 487 W for 38 min result in the maximum betacyanin content (36 ± 1 mg/g dw). The peel extract inhibit the oxidative haemolysis, with IC 50 values of 255 and 381 μg/mL for Δt of 60 and 120 min, respectively, and the growth of pathogenic bacteria, with minimum inhibitory concentrations ranging from 5 to 20 mg/mL. Furthermore, no toxicity was observed for normal cells., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Grape (Vitis vinifera L. var. Albariño) and mulberry (Morus nigra L.) seeds pomace were characterized in terms of tocopherols, organic acids, phenolic compounds and bioactive properties. Higher contents of tocopherols (28 ± 1 mg/100 g fw) were obtained in mulberry, whilst grape seeds were richer in organic acids (79 ± 4 mg/100 g fw). The phenolic analysis of hydroethanolic extracts characterised grape seeds by catechin oligomers (36.0 ± 0.3 mg/g) and mulberry seeds by ellagic acid derivatives (3.14 ± 0.02 mg/g). Both exhibited high antimicrobial activity against multiresistant Staphylococcus aureus MIC = 5 mg/mL) and no cytotoxicity against carcinogenic and non-tumour primary liver (PLP) cells. Mulberry seeds revealed the strongest inhibition (p < 0.05) against thiobarbituric reactive substances (IC 50  = 23 ± 2 µg/mL) and oxidative haemolysis (IC 50 at 60 min = 46.0 ± 0.8 µg/mL). Both seed by-products could be exploited for the developing of antioxidant-rich ingredients with health benefits for industrial application., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The present work focusses on the chemical characterization and bioactive properties of Opuntia joconostle F.A.C. Weber ex Diguet and Opuntia matudae Scheinvar fruits. This research showed that xoconostle cv. Cuaresmeño (O. joconostle) and xoconostle cv. Rosa (O. matudae) are a good source of PUFAs and tocopherols. Moreover, both fruits revealed the presence of ten phenolic compounds (e.g., ferulic acid hexoside, quercetin-O-di-deoxyhexosyl-hexoside, and kaempferol-O-(di-deoxyhexosyl)-hexoside), as well as other organic acids (oxalic, malic, ascorbic and citric acids), and two betacyanins (betanin and isobetain). The hydroethanolic extracts of both fruits exhibited antioxidant activity, and inhibited the growth of several bacteria strains and of the yeast Candida albicans. As expected, xoconostle cv. Cuaresmeño was the fruit with highest antioxidant potential, since it was also the one that showed the highest content of bioactive compounds, with the exception of betacyanins. Overall, both fruits are revealed to be a good source of nutritive and bioactive compounds.

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.

The present study describes a novel mechanical process for the pigmented parts of Gomphrena globosa L. The effects of the variables of the maceration extraction of betacyanins have not been properly described. Therefore, this study also aims to optimize the conditions that maximize betacyanins extraction from G. globosa as an alternative source. Assisted by response surface methodology, an experimental design was developed for testing the extraction variables (time, temperature, ethanol-water proportion and solid-liquid ratio). The responses used were betacyanins quantification (by HPLC-PDA-MS/ESI and spectrophotometric analysis), the extraction-yield and the colour intensity of the produced powder. The betacyanins identified were gomphrenin and isogomphrenin II and III. The highest betacyanins content (∼45mg/g) was obtained by 165min, 25°C, 0% of ethanol and 5g/L of solid-liquid ratio. The betacyanins content from the floral parts of G. globosa is higher than those normally found in other sources highlighting its industrial application., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Organoleptic characteristics largely determine food acceptance, selection, and subsequent consumption. Therefore, food colorants are extremely important in the food industry. However, based on the latest findings related to the side effects and toxicity issues of some synthetic colorants, consumers worldwide have shown increasing interest in natural alternatives. Betalains are good examples of natural colorants and therefore the present study reviews the main sources of these pigments, their structural elucidation and biosynthetic pathways, their chemical instability to different environmental factors, as well as their potential uses at the industrial level and also for pharmaceutical and cosmetic purposes, due to their ability to act as functional ingredients and health enhancers/promoters. Betalain natural pigments represent a promising and safe alternative to synthetic dyes, but their chemical instability has limited their widespread use. Temperature, pH, water activity, oxygen, light, chelating agents, the presence of other compounds, pigment concentration, storage, and processing conditions are the most important factors affecting their stability. It is, therefore, very important to establish optimum processing conditions to maximize the stability of betalains and their extraction yields, focusing on their effective use as natural food colorants, functional ingredients and value-added food products.

Pterospartum tridentatum (L.) Willk., Gomphrena globosa L. and Cymbopogon citratus (DC) Stapf. are examples of medicinal plants with antioxidant properties on their own, but that can be improved when mixed. In the present work, the antioxidant activity and phenolic compounds were determined in the infusions prepared from the individual plants, and from mixtures of these plants in different proportions. P. tridentatum > C. citratus > G. globosa was the order observed for antioxidant efficacy, which can be related to their different composition in phenolic compounds. Synergism was the main effect observed among the tested mixtures, mainly for the infusions prepared from the plants in proportion 40%:60% (either P. tridentatum and C. citratus; or G. globosa and C. citratus). The infusion obtained with 40% of P. tridentatum and 60% of C. citratus gave the highest antioxidant properties. The present study validates the commercialisation of the studied plants combined in specific proportions., (Copyright © 2015 Elsevier Ltd. All rights reserved.)