Thermal and UV degradation of roselle anthocyanin extract and its mixtures with poly(vinyl alcohol) in different acid (original) (raw)
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Effect of Thermal Processes on Roselle Anthocyanins Encapsulated in Different Polymer Matrices
2011
The stability of roselle anthocyanins was investigated under three different heat treatments (60, 80 and 98C). The dry red powder from roselle calyces was produced using spray-drying technique using four different encapsulating agents, i.e., maltodextrin, gum arabic, a combination of maltodextrin and gum arabic, and soluble starch. The four types of matrices increased the half-life of the pigments during heat treatment, especially at 98C (P < 0.05), compared with the roselle extract as the control. Heat treatment results showed that the combination of maltodextrin and gum arabic had the lowest degradation kinetic rates at 60 and 80C. Arrhenius parameters' results further confirmed that the degradation of anthocyanins was strongly dependent on the operating temperatures during heat treatment. In this study, all encapsulating agents, except the soluble starch, largely elongated the halflife of roselle anthocyanins compared with the nonencapsulated anthocyanins. PRACTICAL APPLICATIONS A spectrum of natural, red-hue primer colorants is derived from roselle plant extracts, which is substantially free of alkaloids, enzymes, aroma or solvent residuals, and is microencapsulated to ensure good stability and shelf life. This study measured the thermal stability and suitability of the microencapsulated natural colorants. The colorants are for functional use in the food, pharmaceuticals, cosmetics and other industries.
Evaluation of the pH and thermal stabilities of rosella anthocyanin extracts under solar light
Beni-Suef University Journal of Basic and Applied Sciences, 2015
Anthocyanin is considered as an unstable pigment, undergoes gradual degradation processes throughout the storage or use. The degradation of Rosella anthocyanin extract (RAE) in different pH solutions was studied under solar light and compared with solutions kept in the dark. It appears that RAE solutions under solar light were suffering rapid degradation than those kept in the dark. Moreover, RAE samples at higher pH values showed faster rates of degradation than those with lower pH values. A mechanism for degradation was suggested through the formation of hydroxyl radical which is responsible for demineralization process. It is also appears that as the initial concentration of the dye increases, the requirement needed for degradation increased as well. The thermal degradation behavior of RAE at temperature range 25-60°C under solar light showed first order kinetics with low activation energies.
Analysis of anthocyanin colour stability from fruits of Ixora siamensis / Nur Amirah binti Mat Nor
2012
This studies are to identify the potential of fruits from Ixora siamensis ("pokok jejarum") as a new source of antocyanin natural colourant and to evaluate the suitability of the anthocyanin natural colourant with ferulic acid (FA) stabilizing agent when blended with poly(vinyl) alcohol (PVA) to form a coating system. Furthermore, the aim is to analyse colour stability of anthocyanin colourant in a coating system in terms of pH and copigmentation under UV-B exposure by CIE colour system. The natural anthocyanin colourant from Ixora siamensis was extracted by using acidified methanol for crude extraction. Further purification of crude extraction was performed by using liquid-liquid partition extraction and ion exchange column chromatography. Different proportions of ferulic acid as stabilizing agent were added in order to improve and enhance the resistance towards the UV-B irradiation during exposure period. FA added colourant was mixed with PVA to develop coating system. To test the colour stability of crude and purified anthocyanin colourant and anthocyanin-PVA blend towards UV-B irradiation, CIE colour analysis was conducted. CIE results obtained were analysed in terms of L* C* Hº a* b* colour coordinate values. Total colour difference (ΔE) and saturation (s) of colour were determined in order to evaluate the visual colour variation. Based on the results obtained, the colour of the untreated anthocyanin colourant and anthocyanin-PVA blend was susceptible to UV degradation during 93 days of exposure. The addition of 2% FA at pH 3 performed better colour stability. CIE results also showed that the colour variation of anthocyanin and anthocyanin-PVA blend definitely influenced by pH variation.
Roselle anthocyanins as a natural food colorant and improvement of its colour stability
Roselle anthocyanins extract solution at a pH of 2.5, 13.5oBrix, was subjected to freeze- drying. Maltodextrin and trehalose, each at 2 and 3% (w/v), were used as stabilisers in freeze- dried powder. Freeze-dried powder without a stabiliser was used as a control. During a 15- week storage period at 30oC, anthocyanins content and colour were evaluated. Addition of maltodextrin and trehalose retarded degradation of anthocyanins. The roselle powder containing 3% (w/v) maltodextrin provided superior stability over other stabilisers and was then used in a model system of a drink. During the storage, the rate of colour changes in a drink containing roselle anthocyanins extract was higher than that in drinks containing either SAN RED RC® or synthetic carmoesin. Decreases of chroma with increases of lightness were observed, while there was not much change in hue angle. The overall preference of the drinks containing either SAN RED RC® or carmoesin remained "acceptable" throughout,...
Physico-chemical properties of Roselle calyces (Hibiscus subdariffa) indicated that moisture content, protein, fat, fiber and ash were 12.81 %, 7.51%, 0.46 %, 11.17 % and 11.24 %, respectively. Mineral contents of K, P, Na Ca, Mg, Fe, Zn, Cu and Mn were detected at different levels. The results showed that the Roselle calyces powder more the red color. Besides, contained ascorbic acid (140.13 mg/100g), total anthocyanins (622.91 mg/100g) and total phenolics (37.42 mg/g dry weight). The DPPH scavenging capacity obtained from raw dried Roselle was 36.53 µ/ml. The extraction of natural pigments (anthocyanins) from Roselle calyces by different solvents (ethanol acidified with 1.5N/L HCl (85:15, v/v), ethanol acidified with 1% citric acid, citric acid. solution of 2% concentration and distilled water) were applied and pigments were analyzed for color, pH, total acidity, total soluble solids (T.S.S), total anthocyanins, total phenolic and antioxidants activity. The obtained results indicated that the highest yield of pigment recovered is considered the main goal in the extraction process. In addition to economic considerations, safety should be considered. Accordingly, water acidified with citric acid 2 % indicating anthocyanins yield of 1063 mg/100 g might be the best choice and the more preferable solvent compared with ethanol acidified with HCl which showed the highest yield i.e. 1386 mg/100 g dry weight. The results from this study showed that the greater the Roselle extracted by 2 % citric acid solution the more the red color intensity observed (a* 5.25). Results of these studies can be used to determine application of Roselle anthocyanins in a variety of food products as food colourants such as confectionery products, gelatin desserts, snacks, cake, pudding, ice cream and beverages. [Azza A. Abou-Arab, Ferial M. Abu-Salem and Esmat A. Abou-Arab. Physico-chemical properties of natural pigments (anthocyanin) extracted from Roselle calyces (Hibiscus subdariffa). Journal of American Science 2011;7(7):445-456].(ISSN: 1545-1003). http://www.americanscience.org.
Evaluation of Color Sensitivity to Dyeing Parameters in Natural Dyeing with Anthocyanin
2017
as literature review shows it is possible to replace synthetic dyes with echo-friendly ones as natural dyes. Although plants exhibit a wide range of colors, not all of these pigments can be used as dyes directly. Sunflower seed is one of the popular vegetal cooking oil source used in Iran, as well as in the world. The main colorants in the sunflower seed hulls (SFSH) are anthocyanin. Anthocyanin dyestuffs are mainly used in food industry. Most of the purple, blue and black fruits are sources of anthocyanin. Anthocyanins can be used as pH indicators because their color changes with pH. The aim of this study is to understand firstly the SFSH useable source for textile dyeing and secondly the effect of dyeing bath pH, temperature and dye concentration on the woolen yarn properties. The range of color developed on dyed materials are evaluated in terms of (L*, a*, b*) CIE LAB coordinates and the dye absorption concentration on the woolen yarn dyed by SFSH is studied by using K/S values. Also fastness tests on dyed samples for light and washing fastness were carried out. CIELab coordinates of the samples change in different dyeing processes. This could be explained with presence of anthocyanin components that are sensitive to pH and temperature. The study of the effects of different factors on dye ability of wool by SFSH extract showed that the pH and the temperature of dye bath considerably affected the color yield. The best results were obtained at pH 3.5 and boiling temperature.
Journal of Pharmacognosy and Phytochemistry, 2018
An investigation was carried out to know the biochemical changes in the extracted pigment from roselle (Hibiscus sabdariffa L.) calyces for edible colour during storage. For knowing the storage stability of extracted pigment, it was kept for 3 months in both ambient and refrigerated conditions. In storage under ambient and refrigerated condition, a decreasing trend were observed in the anthocyanin content, total phenols, water activity in the extracted pigment obtained by different methods of extraction upon storage under both conditions. At 90 days after storage at ambient and refrigerated condition, the anthocyanin content of 802.62 and 1091.92 mg 100 ml-1 and total phenols of 4.29 and 5.56 mg ml-1, were found be highest in treatment ethanol acidified with 1.5 N HCl. The water activity was found be highest 0.91 and 0.92 in the treatment of hot water extraction during 90 DAS under both conditions respectively. An increasing trend was observed in the total soluble solids of extracte...
Anthocyanin pigments are responsible for the attractive red to purple to blue colors of many fruits, vegetables, flowers, and cereal grains. In plants they serve as attractants for pollination and seed dispersal, give protection against the harmful effects of UV irradiation, and provide antiviral and antimicrobial activities. Anthocyanin-based colorants are commercially manufactured for food use from horticultural crops and from processing wastes. There is a large body of knowledge on anthocyanin chemistry in the literature that includes established, systematic methods for identifying anthocyanins and measuring their concentration and color properties. Structural variation (B-ring substitution, glycosidic substitution, and acylation) produces a multi-plicity (over 400) of anthocyanins. Color intensity and hue, as well as stability, are markedly affected by pH, which can be a major limitation for many food applications. Increased glycosidic substitution and acylation with cinnamic acids will improve pigment stability. However, the matrix in which the pigments exist can have a much greater impact on pigment degradation. Anthocyanin pigments are very effective scavengers of free radicals. Currently, there is much research activity on their possible health benefits. While anthocyanin-based colorants are universally approved for food use, there are considerable regulatory differences among countries.
Annals.Food Science and Technology, 2019
Red cabbage and purple yam are considered as rich sources of acylated anthocyanin compounds which are important in the natural food colourant industry due to their unusual storage stability. In this study pigment stability and color characteristics of model juice systems colored with anthocyanin extract from purple yam and red cabbage were evaluated for a period of six months(27 weeks) under two different storage temperatures. Reflectance spectrometric analysis and colour quantification in terms of CIELab coordinates were adopted for the present study. Color characteristics of juice model systems coloured with anthocyanins were comparable to the colour tone produced by synthetic colourant FD&C red # 3.Stability traits like pigment retention percentage, monomeric anthocyanin content and polymeric color percentage were measured spectrophotometrically and half-lives of pigments at different storage temperatures were calculated. Storage temperature influenced the stability and color characteristics of purple yam and red cabbage anthocyanins. At room temperature, purple yam anthocyanins showed higher pigment retention and stable color characteristics than red cabbage anthocyanins. Refrigeration improved half-life of purple yam anthocyanin for up to 141 weeks. Results suggested the applicability of purple yam anthocyanins as a stable alternative to the red artificial colorant in juice systems.