Anthocyanins have been shown to possess specific antioxidant capacities, which may provide an underlying protective effect against many chronic diseases . Although the antioxidant capacity of anthocyanins has been well established, less is known about the extent to which specific anthocyanin composition affects total antioxidant capacity . The aim of the present study was to compare the antioxidant capacity of two different soft fruits, blackcurrant and grape, which have distinctly different anthocyanin profiles. The anthocyanin profiles of grape and blackcurrant were characterized by HPLC/MS coupled with a diode array detector. Results showed that blackcurrant contained four predominant anthocyanins, cyanidin 3-glucoside, delphinidin 3-glucoside, cyanidin 3-rutinoside, and delphinidin 3-rutinoside . In contrast, malvidin 3-glucoside, delphinidin 3-glucoside, cyanidin 3-glucoside, petunidin 3-glucoside, and peonidin 3- glucoside were the major anthocyanins found in grape . The concentration of individual anthocyanins in all berries was quantified with HPLC/UV using cyanidin 3-glucoside as an external standard . Finally, results showed a greater (p<0.05) antioxidant capacity of blackcurrant compared to grape. The total antioxidant capacity of crude extracts from each was measured by Oxygen Radical Absorbance Capacity (ORAC) and ABTS assays. Anthocyanin antioxidant capacity index (AACI), derived from the product of antioxidant (ORAC) activity for each of major anthocyanin present in blackcurrant and grape, was also used to determine whether the antioxidant capacity of crude anthocyanin fractions represents either the sum total anthocyanin content or, alternatively, a synergy between different anthocyanins components . Our results indicated that a plausible potential synergy between anthocyanin components in regards to ORAC antioxidant capacity existed in blackcurrant and grape semi-purified anthocyanin extracts. Furthermore, it could be concluded that both total anthocyanin content as well as the composition of individual anthocyanins in soft fruits is important to assess total antioxidant capacity of different berry sources .

Traditional processing technologies can negatively affect polyphenolics of blueberry products. Optimization of hydrothermodynamic (HTD) processing has been used to minimize blueberry-based product quality degradation. Preliminary experiments have shown that the quality of HTD blueberry purée in terms of anthocyanin concentration and tannin content was significantly higher than that of most commercial blueberry products. HTD technology provided pasteurization with significantly lower losses of anthocyanins as compared with conventional heating. Screening of the factors has shown that holding time, temperature of pasteurization and heating rate were significant, while cavitation mode was non-significant. Response surface methodology was used to determine an optimal combination of temperature and time (92 to 95°C with holding time 0.5 to 2.0 min). Non-linear regression analysis of the shelf-life data has provided fitted models which could be used to predict changes in anthocyanin concentration and tannins for different storage periods at 4°C and at room temperature (20 to 25°C).

Red radish anthocyanin extract (RAE) was investigated for coloring brined cherries as an alternative to FD&C Red No. 40. Red radish (Raphanus sativus L.) anthocyanins were extracted from liquid nitrogen powdered epidermal tissue using acetone, partitioned with chloroform, and isolated using C-18 resin. The monomeric anthocyanin content was determined by pH differential to be 154 ± 13 mg/100 g of epidermal tissue (on pelargonidin-glucoside basis). The major pigments were identified as pelargonidin-3-sophoroside-5-glucoside monoacylated with p-coumaric or ferulic acids by HPLC and spectral analyses. Primary and secondary bleached cherries were sweetened to 40° Brix (pH of 3.50), and colored using two concentrations of RAE (600 and 1200 mg/L syrup, designated Cl and C2) and FD&C Red No. 40 (200 ppm). Color was measured for both cherries and syrup. Reflectance measurements (CIE L*, a*, b*), chroma and hue angle, showed that RAE imparted red color to the cherries and syrup extremely close to that of FD&C Red No. 40. RAE C2 gave the primary bleached cherries the closest color characteristics (L*= 18.20, a*= 20.00, b*= 8.47) to FD&C Red No. 40 (L*= 18.00, a*= 24.35, b*= 12.13). RAE Cl gave the secondary bleached cherries the closest color characteristics (L*= 15.27, a*= 16.21, b*= 5.21) to FD&C Red No. 40 (L*= 16.38, a*= 19.91, b*= 8.99). Color and pigment stability of secondary bleached cherries were evaluated during a year of storage in the dark at 25°C. Monomeric anthocyanin degradation followed first-order kinetics and the half-lives were 29 and 33 weeks for syrups colored with RAE Cl and RAE C2, respectively. However, cherry color showed no significant changes in hue, color intensity nor lightness during storage. Color changes of syrup samples over time were dependant on anthocyanin concentration, higher anthocyanin concentration exerted a protective effect on color stability. Haze formation was observed in syrup samples colored with RAE, possibly due to pigment polymerization. Syrup samples colored with RAE and FD&C Red No. 40 were also exposed to light for a year at 25°C. Light had a small but significant effect on L*, a*, and monomeric anthocyanin content. From color and pigment stability data and visual observations we concluded that RAE was effective in coloring secondary bleached cherries with results very similar to those of FD&C Red No. 40 for 6 months of storage. / Graduation date: 1995

Color stability and mouth feel quality are two of the most important aspects of red wine quality. Anthocyanins and proanthocyanidins are responsible for these attributes and it has been shown that weather conditions during the growing season and grape maturity can effect these components in wine. However, investigations into proanthocyanidin development are for the most part incomplete. Although it is known that weather affects vine metabolism, it has not clearly understood how phenolics are affected by temperature and heat summation. It is generally believed that the wines made with riper grapes improve in flavor and mouth feel as a result of an "improvement" in skin tannin "ripeness". The idea of "tannin ripeness" is usually used in the wine industry to explain this phenomenon, however, no scientific explanation for this concept has been given. The objective of this project was threefold: I) Monitor phenolic development in Pinot noir grapes over three consecutive growing seasons and determine how anthocyanin and proanthocyanidin development in grapes was affected by heat summation, II) investigate the transfer of grape phenolics into wine during fermentation and maceration and III) understand how grape maturity affected wine composition with a specific focus on proanthocyanidin structure. In this study, anthocyanin and proanthocyanidin development in Vitis vinifera L. cv. Pinot noir grapes (Pommard clone) were monitored for three consecutive vintages (2001-2003). Five cluster samples (x5 replicates) were collected for analysis each week beginning approximately 4 weeks prior to veraison and continued through commercial harvest. Weather information (temperature and heat summation) showed that the growing seasons became increasingly warmer from 2001 to 2003. By harvest time, 2003 had the highest concentration of proanthocyanidins in seeds (per berry weight) in comparison with the other two vintages. Similarly, proanthocyanidins in skins had the highest concentration in 2003 (per berry weight). However, there was not difference in the concentration of flavan-3-ol monomers in seeds (per berry weight) between the three vintages. Anthocyanins were not significantly different over the three vintages. There was some relationship between the concentration of some proanthocyanidin components in grape seeds and fresh seed weight. Information of grape and wine phenolics was compared with each year's temperature. The results suggested that changes in temperature and heat summation between vintages are associated with changes in proanthocyanidin content in grapes and wine. The data indicates that it is possible to predict proanthocyanidins in wine based upon early grape analysis. However, the anthocyanin content in grapes did not correlate with either weather or the anthocyanin content in wine. The concentration of seed and skin proanthocyanidins in grapes were compared with the proportions of seed and skin proanthocyanidins found in wine. Based upon proanthocyanidin extraction from seeds and skin during winemaking, a formula to predict proanthocyanidin content in wine based upon grape analysis at harvest and veraison was developed. From this formula, Pinot noir wine contained 7.8% of the proanthocyanidins from seed and 19% of the proanthocyanidins from skin analyzed from grapes at harvest, and 3.6% of the seed proanthocyanidin and 9.7% of the skin proanthocyanidin present in grapes analyzed at veraison. Based upon the analyses of this study, coupled with several informal sensory studies conducted on wine, the results of this thesis do not support the notion that "tannin ripeness" is due to structural changes in proanthocyanidin that occur during fruit ripening. Furthermore, this thesis suggests that "tannin ripeness" is not due to differential extraction of seed and skin proanthocyanidins as a result of fruit ripening. / Graduation date: 2005

Graduation date: 1937

Anthocyanins have been shown to possess specific antioxidant capacities, which may provide an underlying protective effect against many chronic diseases . Although the antioxidant capacity of anthocyanins has been well established, less is known about the extent to which specific anthocyanin composition affects total antioxidant capacity . The aim of the present study was to compare the antioxidant capacity of two different soft fruits, blackcurrant and grape, which have distinctly different anthocyanin profiles. The anthocyanin profiles of grape and blackcurrant were characterized by HPLC/MS coupled with a diode array detector. Results showed that blackcurrant contained four predominant anthocyanins, cyanidin 3-glucoside, delphinidin 3-glucoside, cyanidin 3-rutinoside, and delphinidin 3-rutinoside . In contrast, malvidin 3-glucoside, delphinidin 3-glucoside, cyanidin 3-glucoside, petunidin 3-glucoside, and peonidin 3- glucoside were the major anthocyanins found in grape . The concentration of individual anthocyanins in all berries was quantified with HPLC/UV using cyanidin 3-glucoside as an external standard . Finally, results showed a greater (p<0.05) antioxidant capacity of blackcurrant compared to grape. The total antioxidant capacity of crude extracts from each was measured by Oxygen Radical Absorbance Capacity (ORAC) and ABTS assays. Anthocyanin antioxidant capacity index (AACI), derived from the product of antioxidant (ORAC) activity for each of major anthocyanin present in blackcurrant and grape, was also used to determine whether the antioxidant capacity of crude anthocyanin fractions represents either the sum total anthocyanin content or, alternatively, a synergy between different anthocyanins components . Our results indicated that a plausible potential synergy between anthocyanin components in regards to ORAC antioxidant capacity existed in blackcurrant and grape semi-purified anthocyanin extracts. Furthermore, it could be concluded that both total anthocyanin content as well as the composition of individual anthocyanins in soft fruits is important to assess total antioxidant capacity of different berry sources .

Thesis (Ph. D.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 130-141). Also available on the World Wide Web.

Thesis (M.S.)--Ohio State University, 2009. / Title from first page of PDF file. Includes vita. Includes bibliographical references (p. 68-76).

Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 45-47). Also available on the World Wide Web.

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