Grape Pigments, Concord Grape Pigments

Abstract

COLLOIDAL BLUE PIGMENTS OF JUICEThere is usually no difficulty in meeting color requirements in single strength Concord grape juice, but color is more often a limiting factor in grade

Characterization of anthocyanin-containing colorants and fruit juices by HPLC/photodiode array detection

“…A review specific for the anthocyanins for the Concord variety of Vitis labrusca show that the major pigment is delphinidin 3-glucoside followed by (listed in descending order by relative quantity) the 3-glucosides of cyanidin, petunidin, malvidin, and peonidin. Acylations with pcoumaric acid and 3,5-diglucosides of cyanidin and delphinidin have also been reported (Wrolstad, 1976;Ingalsbe et al, 1963;Ohta et al, 1979). A chromatogram of this extract is shown in Figure 9 while spectral data and peak identification are given in Tables II and III.…”

Phenolics in Food and Nutraceuticals

“…The main phenolics identified in Vitis vinifera berries are listed in Table 4.2 and the total content of phenolics in some table grape varieties is summarized in Table 4.3. Anthocyanins are the predominant phenolics of red table grape varieties, while flavan-3ols are the main phenolics in white table grape varieties (Cantos et al, 2002;de Simon et al, 1993;Ingalsbe et al, 1963;Mazza, 1995;Spanos and Wrolstad, 1992). These phenolics contribute to the sensory quality of grape products .…”

Decreasing pH Results in a Reduction of Anthocyanin Coprecipitation during Cold Stabilization of Purple Grape Juice

“…The maximum anthocyanin concentration observed to coprecipitate (0.19% w/w at pH 3.40) was less than the 0.8% w/w content of KHT recovered from cold stabilization of single strength Concord grape juice [10]. The difference between our model system and Concord may be due to the higher concentrations of both acylated and monoglucoside anthocyanins in Concord, which are more likely to coprecipitate [9,10]. pH had a significant and dramatic effect on anthocyanin loss, with a sharp, order of magnitude decrease in anthocyanin content observed at pH ≤ 2.95 as compared to pH 3.4 (Figure 1B).…”

“…In grape juice and wines, an additional source of anthocyanin losses during production is coprecipitation of anthocyanins with potassium bitartrate [9,10,11,12]. Grapes are uniquely high in tartaric acid compared to other fruits, 2–14 g/kg, or 0.01–0.07 M [13], and also contain high concentrations of potassium, 0.01–0.06 M [14,15].…”

“…The factors affecting the kinetics and thermodynamics of KHT precipitation are well studied [19,20,21]. Coprecipitation of anthocyanins with KHT resulted in a 20%–40% loss of total anthocyanins from Concord juice in one report [9], with similar losses reported elsewhere [10,12]. The loss of anthocyanins during cold stabilization is comparable to gains achieved by widely used juice processing treatments such as the use of pectolytic enzymes [22] or thermal treatments [23].…”