ABSTRACT
Interest in food colorants as shown by the number of patents has doubled in recent years with natural pigments outnumbering synthetics by five to one. The natural colorant area can be subdivided into anthocyanins, betalains, chlorophylls, carotenoids, flavonoids, polyphenols, Monascus, hemes, quinones, biliproteins, safflower, turmeric, and miscellaneous. All involve different groups of chemical compounds which may be used directly as colorants, or may be chemically modified to produce different hues or increased stability. All usually involve a method of collection, extraction, purification, possibly stabilization, and formulation. A variety of hues can be obtained ranging from green through yellow, orange, red, blue, and violet, depending on the source of colorant. Similarly, water or oil-soluble formulations can be prepared depending on the type of colorant.
Subject(s)
Anthocyanins , Food Coloring AgentsABSTRACT
The role of acidifying agent in extracting anthocyanins from red onions was investigated. Cl- of HCl disrupted complex structures present in onion tissue to release anthocyanins and also induced formation of other complexes containing the pigment. Formate did not produce these effects. A schematic was developed to illustrate the interaction and decomposition of anthocyanin fractions during HCl extraction. The implications of the presence of Cl- in the extractant on interpretation of extraction results were discussed. Anthocyanins possibly acylated with non-cinnamic acids were considered to be particularly affected by mineral acids in the extractant.
ABSTRACT
Chromatographic fractions of the onion pigment profile were examined for acyaltion by alkaline hydrolysis, visible/UV spectral, IR spectral, GLC, and NMR techniques. Results indicative of acylation were shown by alkaline hydrolysis and IR spectral analyses. The suspected acyl portion was shown not to be a cinnamic acid by visible/UV spectral analysis. NMR and GLC methods failed to detect acylation in the onion pigment system. Small amounts of assay material, low sensitivity for detection of some of the possible acyl acids, removal of the acyl by complex formation, loss of the acyl due to high volatility and low acid transfer in partitioning systems are some of the factors identified as interfering with acyl detection.
ABSTRACT
The stability and color of purified cyanidin-3-glucoside and raspberry juice extract in the presence of selected metal ions was investigated. Production of metal-anthocyanin complexes was suggested by changes in color of the samples as shown by L, a, and hue angle values. Complex formation was indicated by HPLC in raspberry juice samples treated with Sn++ but not in samples of purified cyanidin-3-glucoside. According to the colorimetric values, complex formation occurs with cyanidin-3-glucoside and A1+++ at pH 2.0 and 3.0 and with Sn++ at pH 4.0 and 3.0. Similar complex formation occurs with these metals and raspberry juice extract at the same respective pH values.
ABSTRACT
The direct effect of cinnamic acid on anthocyanin stability in cranberry juice without added ascorbic acid was investigated. The concentration of cinnamic acid was determined throughout the storage study by high-performance liquid chromatography (HPLC), and results indicate no loss of cinnamic acid either due to pasteurization or storage. Cinnamic acid was found to have no significant effect on anthocyanin stability in cranberry juice during storage at ambient temperature at the levels used in this study.
ABSTRACT
A dry powdered pigment extract was prepared from a Roselle liquid concentrate obtained from Trinidad. The pigment base was added to two dry pack foods, a beverage mix and a gelatin dessert, and evaluated under various temperature and humidity conditions. During a 16-week storage period, color, flavor, and pigment stability were evaluated versus those of Red No. 2. All samples were less stable than those with Red No. 2 but showed good stability up to 4 weeks of storage, after which, the rate of pigment degradation accelerated. Reconstituted products showed good light and refrigeration stability but the roselle powder imparted an unacceptable flavor to the products.
ABSTRACT
The equilibrium relative humidity isotherm of a cherry beverage base and a strawberry gelatin dessert mix colored with anthocyanins from grape skins, cranberries and roselle was evaluated versus a Red No. 2 control. As well, the water vapor transmission rate of the packaging material was evaluated to evaluate probable shelf-life. Results indicated that physical parameters, such as hygroscopicity, must be considered in estimating effects of the use of natural colorants in foods as well as the color and chemical stability normally investigated.
ABSTRACT
A dry-powdered pigment extract was prepared from dried cranberry pomace by methanol extraction, concentration and spray drying. The extract was added to a cherry-flavored beverage mix and a strawberry-flavored gelatin dessert mix. The former was packed in foil/paper pouches and the latter in polyethylene/paper pouches. Storage studies were conducted at 40, 75, and 100 F with relative humidity (RH.) values of 10, 40, and 90%, respectively. All were evaluated for color, flavor, and pigment stability versus samples containing Red No. 2. Samples stored at temperatures up to 75 F had considerable breakdown after 12 weeks of storage but still showed acceptable color. Pigment stability was greatly increased with nitrogen flushing, and decreased with increasing temperature of storage, reaching a maximum at 100 F at 90% RH. The pigment extract imparted an astringent flavor which could be detected by triangular panels, and indicated the need for some type of "clean-up" procedure.
ABSTRACT
The degree of consumer understanding, or lack of understanding, may be divided into three groups. The first is the area in which there is a good deal of misinformation being disseminated by groups for economic gain. Examples of this are the diet fads, such as the low carbohydrate diet which has already been resurrected six times under different names. The second area involves knowledge that the public doesn't really want to hear. The best example of this is the guidelines for filth in food published by the FDA. Another related example is the proposed regulations for Fish Protein Concentrate regarding intestinal contents. A third example may be the full ingredient labelling being requested by some groups. A long list of chemical names intimidates some consumers and may actually reduce food credibility. The third area involves technical issues that are so complex that educational efforts have lagged behind the progress of analytical and toxicological advances. The concept of risk/benefit in food components with its attendant difficulties in extrapolating high dosage animal data to low dose data appropriate for humans is the most obvious example.
