Xanthurenic Acid in the Shell Purple Patterns of Crassostrea gigas; First Evidence of an Ommochrome Metabolite in a Mollusk Shell

Ommochromes are one of the least studied groups of natural pigments, frequently confused with melanin and, so far, exclusively found in invertebrates such as cephalopods and butterflies. In this study focused on the purple color of the shells of a mollusk, Crassostrea gigas, the first evidence of a metabolite of ommochromes, xanthurenic acid (XA), was obtained by liquid chromatography combined with mass spectrometry (UPLC-MS). In addition to XA and various porphyrins previously identified, a second group of high molecular weight acid-soluble pigments (HMASP) has been identified with physicochemical and structural characteristics similar to those of ommochromes. In addition, fragmentation of HMASP by tandem mass spectrometry (MS/MS) has revealed a substructure common to XA and ommochromes of the ommatin type. Furthermore, the presence of melanins was excluded by the absence of characteristic by-products among the oxidation residues of HMASP. Altogether, these results show that the purple color of the shells of Crassostrea gigas is a complex association of porphyrins and ommochromes of potentially ommatin or ommin type.

Usage of Natural Colour Indicators in Packaging Materials for Monitorization of Meat Freshness

Food packaging has an important role in protecting food against physical, chemical, and biological hazards during storage and distribution and in informing the consumer about the product. The packaging of foods that susceptible to chemical / microbiological spoilage especially such as meat, hence limited storage time, is even more important than other foods. In addition, the tendency of health-conscious consumers to be a part of real-time controls and monitoring food safety has led to the widening of this packaging perception. Hence, there have been innovative studies in recent years, especially aiming real time monitorization of freshness indicators. The focus of these studies is “colour indicators” used in the production of intelligent indicator films and colorimetric sensors within specific matrices to be integrated into packaging materials. The colour indicators change colour in the presence of certain metabolites released in food spoilage, which allows freshness to be determined. Colour substances used for this purpose can be natural or synthetic. Hence, natural pigments such as anthocyanin, curcumin, etc. have been more preferrable since being harmless to the health as well as increasing tendency of consumers to utilization from natural resources. In this review, information about natural colour indicators and studies in which these indicators are used to determine the freshness of meat in real time and visually are given.

Penambahan pigmen alami yang disalut tepung agar untuk meningkatkan kekuatan antioksidan pada tempe

Background: Tempeh is a traditional Indonesian food that has a relatively low antioxidant activity. The addition of natural pigments is one solution to increase the antioxidant activity of tempeh. However, natural pigments are very susceptible to damage due to environmental factors, so it is necessary to coat with certain materials, such as agar powder to protect the pigments from damage. Research purposes: The aim of the study to analyze the effect of adding natural pigments coated with agar powder on the antioxidant strength of tempeh. Method: The sample used was tempeh with the addition of pigment powder uncoated and coated with 2%, 3%, 4% of agar, and tempeh without the addition of pigments as control. The antioxidant activity strength was analyzed using the DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) method at fermentation time of 0 and 48 hours. Results and Discussion: The results showed that the addition of pigments and fermentation time were able to significantly increase the antioxidant strength of tempeh compared to control where the IC50 value of the control at 0 hours of fermentation was 166,45±38,58 mg/ml which changed to 69,45±3,49 mg/ml after 48 hours of fermentation. Antioxidant activity were stronger in tempeh with addition of pigment where IC50 value of tempeh with uncoated pigments, coated pigments with 2%, 3%, and 4% of agar were 23,53±5,46 mg/ml, 21,91±6,02 mg/ml, 21,53±6,03 mg/ml, and 29,69±11,04 mg/ml, respectively. Nevertheless, the antioxidant activity strength from all treatments were considered as weak (IC50>200 µg /ml). Conclusion: The addition of pigments uncoated and coated with agar powder and fermentation time were able to increase the antioxidant strength of tempeh. Coating treatment is also able to maintain the pigment color from degradation in the fermentation process.

The effect of paper coatings containing biopolymer binder and different natural pigments on printability

Paper is an environmentally friendly, recyclable material whose main material is cellulose, which can be obtained from all kinds of trees and plants, used as writing, printing and packaging material. Due to its structural properties, papers are not resistant to temperature and humidity, as well as problems with ink transfer with its porous structure and experienced negative printability properties. In recent years, especially the growth of the packaging industry has increased the demand for papers with improved printability properties. In order to obtain better printability properties from papers, some processes can be performed in paper production, as well as some surface treatments after production. These processes are paper coating, sizing and calendering. Paper coatings are generally water-dispersed coating solutions with one or more pigments, binders and certain additives to improve the desired properties. With these processes, by filling the gaps between the pores of the paper, a shapely and smooth surface is obtained and good printability is obtained together with the optical and physical properties of the papers. In this study, the interactions and printability properties of different types of pigments with xanthan gum binder were investigated by preparing paper coating formulations using calcium carbonate, barite and talc pigments and xanthan gum as binder. As a result, xanthan is a good coating binder and CaCO 3 {\mathrm{CaCO}_{3}} from the compared pigments is the most suitable compared to the other 2 pigments, considering all the studied areas.

Dyes and pigments used in foods: an integrative literature review

The food colors are, in many countries, widely used to give food increased visual sensory quality, aiming, thus, the growth of the consumer market. Aware of this, the present work aimed to reevaluate the general properties of synthetic food dyes and natural pigments, the latter being generally used to replace the former. Then, the current analysis was based on the search for the strategy, selection of articles (with inclusion and exclusion criteria), eligibility, and data extraction. Thus, it was observed in studies that synthetic food dyes may cause several harmful effects to human health, among them, genetic damage and carcinogenicity. On the other hand, the use of natural pigments as an alternative to replace food dyes has been increasingly present in studies, presenting qualities that, previously, were not known, as is the case of anthocyanins, which have important physiological and ecological functions. It is also important to point out that the use of natural pigments goes beyond the limits of food, and are also found as sensitizers for solar cells, tissues, and medicines. Selected articles (47) leaded to a total of 72 distinct pieces of information, focused mainly on the biological activities and involving natural dyes and pigments. In short, the gradual replacement of dyes, currently used, still in large scale in some locations, by natural pigments, is already part of our present, allowing the creation of a future perspective with the production of processed foods without the damage that most of synthetic dyes produce to the human body.