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George L. Hosfield and Clifford W. Beninger

Seed coat color in dry bean (Phaseolus vulgaris L.) is determined by the presence or absence of tannins, flavonoids, and anthocyanins. Black beans contain three main anthocyanins that are responsible for their black seed coat color: delphinidin 3-O-glucoside, petunidin 3-O-glucoside, and malvidin 3-O-glucoside. Leaching of anthocyanins occurs in many black bean genotypes during thermal processing (i.e., blanching and cooking). Black beans that lose their dark color after processing are unacceptable to the industry. Since the marketability of black beans can be adversely affected by thermal processing, an experiment was conducted to ascertain whether pigment leaching was due to qualitative or quantitative changes in anthocyanins during processing. Four black bean genotypes that showed differential leaching of color were investigated. `Harblack' retains most of its black color after processing while `Raven' loses most of its color. `Black Magic' and `Black Jack' are intermediate between `Harblack' and `Raven' in processed color. Bean samples (119 ± 1.5 g) of the four genotypes were thermally processed in 100 x 75-mm tin cans in a pilot laboratory. Seed coats were removed from the cooked beans, freeze-dried, and placed in solutions of formic 10 acid: 65 water: 25 methanol to extract anthocyanins. The extracts were analyzed by HPLC. Although all genotypes retained some color, there were no detectable anthocyanins in seed coats of the cooked beans. In a second experiment, raw beans of each genotype were boiled in distilled water for 15 minutes. All four genotypes lost color during boiling, but `Harblack' retained most of its color and had a five-fold higher concentration of the three anthocyanins than did the other genotypes. `Harblack' may retain color better than other black beans because of physical characteristics of the seed coat.

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Maria Claudia Dussi, David Sugar and Ronald E. Wrolstad

The anthocyanin in `Sensation Red Bartlett' pear skin was characterized and quantified, and the effect of light quality on fruit color development was evaluated. Anthocyanin concentration was related to fruit chromaticity values. Pigments were analyzed using high-performance liquid chromatography (HPLC) and thin-layer chromatography (TLC). One of two spots detected in the TLC chromatogram did not change color with molybdate sprays, indicating the possible presence of peonidin. HPLC analysis confirmed the presence of a major and a minor pigment, which co-eluted with cyanidin 3-galactoside and peonidin 3-galactoside. Monomeric anthocyanins in the pear skin extract were 6.83 mg/100 g of fruit peel. To study light quality, gelatin filters allowing passage of different wavelengths of-light were attached over the exposed side of `Sensation Red Bartlett' pears 1 month before harvest. Chromaticity was recorded before the filters were attached and after their removal at harvest using the Commission Internationale del'Eclairage (L*, a*, and b*) color space coordinates. Following color measurements, anthocyanin was extracted from individual skin disks. Skin beneath all filters yielded less hue than the control. Wavelengths that transmit above 600 nm had the largest effect on chroma, a*, and b* values. Fruit wrapped in aluminum foil to obscure all light had the highest luminosity. Wavelengths from 400 to 500 nm gave darker, less chromatic, and redder pear fruit. All treatments yielded higher anthocyanin content than the control. There was a tendency toward increased anthocyanin content with longer wavelengths. The simple linear regression of the log anthocyanin content on L* value and (a*/b*) provided an R 2 = 0.41.

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Eric T. Stafne, Amir Rezazadeh, Melinda Miller-Butler and Barbara J. Smith

; Clark, 2008 , 2013 ; Fernandez, 2012 ; Ruhl, 2010 ). It is a problem that does not appear to have a simple, single cause. Anthocyanin synthesis has been known to be affected by environmental conditions such as growth temperature. Steyn et al. (2004

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Tomomi Tsuda, Masami Yamaguchi, Chikako Honda and Takaya Moriguchi

We used RNA blot analysis to examine the expression of six genes of the anthocyanin biosynthesis pathway in the flowers and fruit skins at three developmental stages of white and red peaches and a deep-red nectarine [Prunus persica (L.) Batch]. In the red peach `Akatsuki' and the deep-red nectarine `Flavortop', expression levels of anthocyanin biosynthesis genes were related to anthocyanin accumulation in the fruit skin; expression of all six genes dramatically increased at Stage III of fruit development, and anthocyanin concentration also increased at this stage. In the white peach `Mochizuki', however, expression of the chalcone synthase gene (CHS) and the dihydroflavonol 4-reductase gene (DFR) was undetectable in Stage III, although the chalcone isomerase gene (CHI), the flavanone 3-hydroxylase gene (F3H), the anthocyanidin synthase gene (ANS), and the UDP-glucose-flavonoid 3-O-glucosyltransferase gene (UFGT) were expressed. We occasionally found red pigment in the skin of `Mochizuki' peach. In these red skin areas, both CHS and DFR were clearly expressed in Stage III. These results suggest that CHS and DFR are the key regulatory genes in the process of anthocyanin biosynthesis in mature red peach and nectarine.

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Nicholi Vorsa, James Polashock, David Cunningham and Robin Roderick

A diversity of anthocyanins exists among angiosperm species. Studies indicate that various anthocyanins differ in antioxidant potential, their bioavailability, and stability during processing. The fruit of the American cranberry, Vaccinium macrocarpon Ait., is recognized as having six anthocyanins, composed largely of 3-O-galactosides and 3-O-arabinosides, and to lesser amount (≈6%), 3-O-glucosides of the aglycones cyanidin and peonidin. This study analyzed proportions of these six anthocyanins from >250 accessions of a germplasm collection over harvest dates. Fruit samples from 78 selected accessions, based on the first year analysis, were also analyzed a second year. Principal component analysis identified general negative relationships between the proportions of cyanidin versus peonidin, arabinosides versus glucosides, and galactosides versus arabinosides and glucosides. These relationships were consistent across the 2 years. Most variation in germplasm anthocyanin profiles reflected variation of cyanidin versus peonidin proportions, with cyanidin to peonidin ratios ranging from 3.6:1 to 0.5:1. Variation for glycosylation profiles was also evident, with galactoside proportions ranging from 64% to 75%, arabinoside proportions ranging from 20% to 33%, and glucoside proportions ranging from 3% to 9%. Evidence for both significant qualitative and quantitative genetic variation exists for the methoxylation of cyanidin to peonidin. Significant quantitative genetic variation is also apparent for glycosylation.

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Karim M. Farag, Jiwan P. Palta and Elden J. Stang

The application of ethanol for enhancing effectiveness of ethephon under field conditions on cranberry (Vaccinium macrocarpon Ait.) fruit was tested during three seasons (1986 to 1988). The formulation containing ethephon plus the surfactant Tergitol (0.3% or 0.5%, v/v) and ethanol (2.5%, 5%, or 10%) consistently increased anthocyanin content in the fruit by 28% to 54% over the control. In general, fruit size was not affected by the ethephon treatment containing ethanol and Tergitol. The application of ethephon plus surfactant did not increase the anthocyanin content in the fruit. The presence of ethanol in the ethephon and surfactant mixture, however, consistently enhanced the fruit anthocyanin content by 21% to 40% as compared to ethephon plus surfactant. No adverse effect of various treatments on vine growth or appearance was noticed over the three seasons. Chemical name used: (2-chloroethyl) phosphonic acid (ethephon).

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W. Kalt, J.E. McDonald and S. MacKinnon

Fruit and vegetable components that possess antioxidant capacity are being actively investigated because of the purported impact of dietary antioxidants on human health. Phenolic components, including anthocyanins, are believed to be major contributors to the antioxidant capacity of many small fruit species. Various horticultural factors have been examined with respect to anthocyanin and phenolic content, and antioxidant capacity of small fruit, especially Vaccinium species. Vaccinium species, and certain other fruits, had a high antioxidant capacity compared to strawberries and raspberries. However, genotypic variation in these characteristics was substantial among wild blueberry clones. Fruit maturity did not influence antioxidant capacity, although phenolic profiles changed dramatically during ripening. Fresh storage of certain ripe fruit at 20 °C led to increased anthocyanin content and increased antioxidant capacity. Certain food processing factors, such as heat and oxygen, decreased the antioxidant capacity of blueberry products.

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Zhiguo Ju, Chenglian Liu, Yongbing Yuan, Yongzhang Wang and Gongshi Liu

Crosses between red cultivars produced high frequency of less-colored progeny, while hybridization between non-red cultivars yielded some red-fruited F1 trees. When harvest was delayed and light intensity increased, both green and yellow cultivars accumulated some anthocyanin with higher UDPGal:flavonoid-3-o-glycosyltransferase (UFGalT) activity in colored areas. Overall, anthocyanin accumulation and UFGalT activity were highly correlated (r = 0.8921, P = 0.0001) in fruit from both parental trees and their F1 progeny, but UFGalT activity always was relatively high in fruit peel, whether anthocyanin accumulated or not. There were no significant differences in phenylalanine ammonia-lyase or chalcone synthase activities among the cultivars, and they did not change much after hybridization.

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Brett Suhayda, Carolyn J. DeMoranville, Hilary A. Sandler, Wesley R. Autio and Justine E. Vanden Heuvel

fungal diseases ( Oudemans et al., 1998 ). As with flower bud formation, fruit anthocyanin production depends on adequate light penetration ( Strik and Poole, 1991 ; Toledo et al., 1993 ). The cranberry fruit must exceed a minimum anthocyanin content to

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C.R. Brown, D. Culley, C.-P. Yang, R. Durst and R. Wrolstad

A breeding effort designed to increase the antioxidant level of potato (Solanum tuberosum L.) by means of high concentrations of anthocyanins and/or carotenoids provided selected materials for analysis. Extraction methods suitable for isolating both hydrophilic and lipophilic compounds were used and measurements of total anthocyanin and total carotenoid were made. Two methods of measurement of oxygen radical absorbance capacity (ORAC) adapted to hydrophilic and lipophilic compounds were applied. Total anthocyanin values varied between 9.5 and 38 mg per 100 g fresh weight (FW). The hydrophilic fraction ORAC measurements among anthocyanin-rich clones varied between 250 and 1420 μmol Trolox equivalents per 100 g FW. These two variables were significantly correlated, r = 0.73, and with significant positive slope in linear regression. Measurement of total carotenoids revealed differing degrees of yellowness covered a range of total carotenoid extending from 35 to 795 μg per 100 g FW. Dark yellow cultivars had roughly 10 times more total carotenoid than white-flesh cultivars. The lipophilic fraction ORAC values ranged from 4.6 to 15.3 nmoles α-tocopherol equivalents per 100 g FW. Total carotenoid was correlated with the lipophilic ORAC values, r = 0.77, and also had a statistically significant positive regression coefficient. Clones with red and yellow pigments visible in the flesh had anthocyanins and carotenoids in elevated levels and ORAC contributions from both fractions. The introgression of high levels of carotenoid from germplasm directly extracted from the Papa Amarilla (yellow potato) category of cultivars of South America into long-day adapted North American materials is presented here. Although anthocyanins and carotenoids are major contributors to antioxidant activity, other constituents of potato flesh likely play significant roles in total antioxidant values.