Anthocyanin pigment, nonvolatile acid and sugar composition of blackberries

Graduation date: 2000The pigments of blackberry fruit were investigated by analytical and preparative\ud high performance liquid chromatography (HPLC) to characterize anthocyanin\ud patterns in commercially important blackberry (Rubus eubatus) cultivars and\ud selections. Five anthocyanin pigments were detected in Evergreen blackberry and\ud they were identified as cyanidin-3-glucoside, cyanidin-3-rutinoside, pentosecyanidin\ud derivative and two acylated cyanidin derivatives. The monomeric\ud anthocyanin of 52 samples ranged from 70.3 to 201 mg/100g berry (mean = 137).\ud For commercial juice concentrates, it ranged from 12.3 to 107 mg/100g single\ud strength juice. One of the ten commercial juice concentrates showed an atypical\ud chromatogram.\ud Analyses of nonvolatile acids and sugars were conducted on 52 samples of\ud blackberry to develop a compositional database for evaluating authenticity and\ud quality. °Brix ranged from 6.88 to 16.83 with a mean of 10.82. Titratable acidity\ud ranged from 0.52 to 2.24 with a mean of 1.35 g citric acid/l00mL. Sucrose levels\ud (range, 0-12.9%; mean, 4.07%) were highly variable. The overall glucose: fructose\ud ratio ranged from 0.81 to 1.17 with a mean of 1.01. The identities of malic,\ud isocitric, lactoisocitric, shikimic and citric acids were confirmed. Two patterns of\ud nonvolatile acid compositions were found in blackberries. Malic acid ranged from\ud 5.2% to 35.3% (87.5-603 mg/100g) of total acids with a mean of 16.4% (280\ud mg/100g). Lactoisocitric acid ranged from 3.4-32.6% with a mean of 17.3% (mean,\ud 293 mg/100g). Isocitric acid ranged from 79.1 to 1550 mg/l00g (mean, 599\ud mg/100g). Citric acid ranged from 15.2 to 1892 mg/100g (mean, 572 mg/100g).\ud Presence of fumaric acid has not previously been reported. Succinic acid was\ud detected in some samples. Ten commercial samples were also analyzed which\ud exhibited HPLC profiles similar to the anthentic standard. It was possible to\ud classify the commercial concentrates as to whether they were Marion, Evergreen or\ud a mixture of the two from their acid profiles. The pigment profile may help in\ud determination of authenticity of juice in terms of international trade. The data from\ud pigment concentration measurement should be useful in breeding programs