Purple Hue Research Articles

Characterization of Anthocyanin-Rich Waste from Purple Corncobs (Zea maysL.) and Its Application to Color Milk

Pigment production from anthocyanin-rich purple corncobs generates a deeply colored waste precipitate. Our objectives were to characterize this anthocyanin-rich waste (ARW) and to find a suitable application in a food matrix. Composition and solubility characteristics of ARW were evaluated. Color (CIELAB) and pigment (monomeric anthocyanin and HPLC profiles) stability of ARW in milk (35 mg/100 mL) were evaluated using an accelerated test at 70 degrees C and phosphate buffer as a control. ARW provided milk an attractive purple hue (324-347 degrees ). Monomeric anthocyanin degradation followed zero-order kinetics in skim and whole milk and second-order kinetics in the control, with half-lives of 173, 223, and 44 min at 70 degrees C, respectively. ARW shows potential as a natural colorant for a pH range unusual for anthocyanin applications. A protective effect of matrix constituents on the stability of anthocyanins was evident. Anthocyanins may interact with different compounds in biological systems when the pH values are close to neutral.

A new vinylpyranoanthocyanin pigment occurring in aged red wine

A new pyranoanthocyanin–vinylphenol pigment was detected in an aged Port red wine. The UV–Vis spectrum of this pigment was found to have a λ max of 538 nm that is bathochromically shifted from that of original anthocyanins, exhibiting a more purple hue in acidic solution. This newly formed pigment was synthesized in model solution through the reaction between malvidin 3- O-glucoside–pyruvic acid adduct and vinylphenol and its structure was assigned by NMR and mass spectrometry. This pigment is reported herein for the first time.

The Painful Purple Digit: An Alarming Complication of Candida albicans Antigen Treatment of Recalcitrant Warts

Candida albicans (CA) antigen immunotherapy for recalcitrant warts is a novel treatment that has had much success in the recent past. Although several side effects are well documented in the literature, we report a new adverse reaction to CA antigen immunotherapy for verruca vulgaris of the distal fingertip. Our patient received an intradermal injection of CA antigen solution into periungual warts located on the distal left thumb and distal subungual area of the left index finger. Within 24 hours, the patient reported pain, edema, and a purple hue to only the index finger. Incision of the finger demonstrated no hematoma or compartment syndrome. Although the etiology is unknown, we believe the condition was most likely due to edema and vascular compromise secondary to a vigorous delayed-type hypersensitivity reaction, possibly leading to cyanosis of the distal index finger. We report this case to make physicians who use intralesional CA antigen aware of a new possible complication at this anatomic location.

Molecular Cloning and Biochemical Characterization of a Novel Anthocyanin 5-O-Glucosyltransferase by mRNA Differential Display for Plant Forms Regarding Anthocyanin

UDP-glucose: anthocyanin 5-O-glucosyltransferase (5-GT) is responsible for the modification of anthocyanins to more stable molecules in complexes for co-pigmentation, supposedly resulting in a purple hue. The cDNA encoding 5-GT was isolated by a differential display applied to two different forms of anthocyanin production in Perilla frutescens var. crispa. Differential display was carried out for mRNA from the leaves of reddish-purple and green forms of P. frutescens, resulting in the isolation of five cDNA clones predominantly expressed in the red form. The cDNA encoded a polypeptide of 460 amino acids, exhibiting a low homology with the sequences of several glucosyltransferases including UDP-glucose: anthocyanidin 3-O-glucosyltransferase. By using this cDNA as the probe, we also isolated a homologous cDNA clone from a petal cDNA library of Verbena hybrida. To identify the biochemical function of the encoded proteins, these cDNAs were expressed in Saccharomyces cerevisiae cells. The recombinant proteins in the yeast extracts catalyzed the conversion of anthocyanidin 3-O-glucosides into the corresponding anthocyanidin 3,5-di-O-glucosides using UDP-glucose as a cofactor, indicating the identity of the cDNAs encoding 5-GT. Several biochemical properties (optimum pH, Km values, and sensitivity to inhibitors) were similar to those reported previously for 5-GTs. Southern blot analysis indicated the presence of two copies of 5-GT genes in the genome of both red and green forms of P. frutescens. The mRNA accumulation of the 5-GT gene was detected in the leaves of the red form but not in those of the green form and was induced by illumination of light, as observed for other structural genes for anthocyanin biosynthesis in P. frutescens.

The alexandrite effect of theTavernier diamond caused by fluorescence under daylight

The 56.07-carat Tavernier pear-shaped gem di- In his report, Tavernier described a diamond locality amond not only has an important historical provenance, called the Gani mine. A number of rough diamonds were but also shows a substantial color change between incan- found there, many ranging in weight from 10 - 40 carats, descent light and daylight. This famous diamond exhibits with the largest weighing 900 carats ( 1 caratA 0.2 gram) . a very strong blue fluorescence when exposed to long- He mentioned that the colorless to light yellow diamonds wavelength ultraviolet (UV) radiation. It appears light from this area as having a ''greasy'' appearance in day- brown (an orange hue) under incandescent light, and light. This kind of diamond has since been described as light pink (a purple hue) under daylight. This change in being of ''false color,'' in that the appearance is due to color, or ''alexandrite effect,'' is caused by its very strong the lighting conditions, and is not the true bodycolor. blue fluorescence resulting from the long-wavelength ul- Wade discussed the kind of ''greasy'' diamond reported traviolet component present in daylight.q 1998 John Wiley & by Tavernier, and pointed out that this ''false color'' is Sons, Inc. Col Res Appl, 23, 323 - 327, 1998 caused by a blue fluorescence under daylight. 2 Light yel- low diamonds from the Premier Mine in South Africa

Site-dependent development of complete and incomplete intestinal metaplasia types in the human stomach.

The topographical distribution of complete and incomplete types of intestinal metaplasia in human stomach samples was investigated in order to elucidate their mutual histogenetic relationship and significance in carcinogenesis. Subgross stereomicroscopic examination of alcian blue and hematoxylin‐stained gastric mucosae allowed clear distinction of complete and incomplete intestinal metaplasia types as white (with or without purple hue) and purple foci, respectively, against the background magenta areas of non‐intestinalized mucosa. Intestinal metaplasias which developed in the fundic area were predominantly of the complete type whereas those of the antrum were a mixture of both with a distinct predilection for expression of the incomplete type. Although there was some variation among foci regarding the hue of white or purple, the color feature was principally homogeneous within each individual intestinal metaplasia focus. Thus phenotypic analysis indicated intestinal metaplasia expression to be clearly influenced by intragastric topography. The study did not provide any evidence that a shift from incomplete to complete type intestinal metaplasia may occur with time or that the incomplete type may be more intimately associated with development of well‐differentiated carcinomas.

Color scaling of chromatic increments on achromatic backgrounds: Implications for hue signals from individual classes of cones

AbstractThe hues of foveal monochromatic increments on concentric white backgrounds were measured as a function of the background retinal illuminance. For each background illuminance tested, the illuminance of the test spot was set 0.6 log unit above its increment threshold, and relative percentages of redness, yellowness, greenness, and blueness were estimated. The percentage of whiteness was also estimated in a separate judgement. At low background illuminances, the spectrum is dominated by blue at short and middle wavelengths and by red at long wavelengths. Higher background illuminances are marked by dramatic growth of yellow and green at middle wavelengths and red at short wavelengths. At still higher photopic levels, the pattern reverts back toward that seen at low background illuminances. The hue patterns at low and high adapting levels are characteristic of tritanopic vision, and are attributable to selective sensitivity losses in chromatic neural pathways that process short‐wavelength‐sensitive (S) cone responses. These results reinforce previous evidence that S cone activity produces a reddish purple hue at short wavelengths and (indirectly) a yellow hue at middle and long wavelengths, and that middle‐wavelength‐sensitive cone activity produces a slightly greenish blue.

Protoporphyrin‐IX as a Substitute for Nitrite in Cured‐Meat Color Production

ABSTRACTThe iron‐free heme derivative protoporphyrin‐IX, was added to a cooked emulsified beef product to mimic the typical cured‐color obtained with nitrite. Although the pigment was stable and could be recovered from the emulsion it imparted a purple hue as noted by visual observation and Hunterlab color values (L,a,b). The possible implications of this pigment as a meat colorant are discussed.

SELECTIVE STAINING OF DISEASED AREAS IN CARTILAGE BY INTRA-ARTICULAR INJECTION OF DYES

The intra-articular injection of dyes is not a new procedure, though practiced only from the experimental standpoint to determine the absorptive capacity of the synovial membrane and the paths of absorption. A review of the literature indicates that no attention has been paid to the gross staining of cartilage by dyes. Tillmanns, in 1876, injected berlin blue into the bony canals of the amputated femurs of his experimental animals, after cutting away the bony plate that intervenes between the femur and the joint cavity. He intended to study the absorptive power of the synovia, without injuring either synovia or capsule. In seven cases, he noted a superficial staining of cartilage, easily washed out by a stream of water. Schreiber of Tubingen, in 1904, in analyzing the constituents of Belchier's madder, noted that purpurin, injected into the dorsal lymph sac of the frog, stained cartilage vitally a purple hue. The gross