SUGAR, NONVOLATILE ACID, C-13 C-12 RATIO, AND MINERAL ANALYSIS FOR DETERMINATION OF THE AUTHENTICITY AND QUALITY OF RED RASPBERRY JUICE COMPOSITION/

Analyses of sugars, nonvolatile acids, C-13/C-12 ratios, and minerals were conducted on 46 samples of red raspberry (Robus idaeus) to develo p a compositional database for evaluating authenticity and quality. Sa mple differences included cultivar (n = 10) and factors such as maturi ty, geographic origin, mold contamination, and harvesting procedures. A pilot-plant process typical of conventional commercial processing op erations was used to process juices, along with newer technologies suc h as enzymatic liquefaction, diffusion extraction, and direct osmotic concentration. degrees Brix ranged from 7.0 to 15.0 with a mean of 9.9 5. All data have been normalized to 9.2 degrees Brix. Sorbitol express ed as percentage of total sugars ranged from 0 to 0.5% with a mean of 0.15%. Sucrose levels (range, 0-24.1%; mean, 1.4%) were highly variabl e. The glucose:fructose ratio ranged from 0.76 to 1.03 with a mean of 0.93. Citric acid is the major acid, ranging from 89.8 to 98.9% of tot al acids (mean, 95.6%; 1.70 g/100 mL). Malic acid ranged from 0.3 to 9 .6% of total acids with a mean of 3.3% (66.1 mg/100 mL). Isocitric aci d ranged from 0.2 to 2.6% (5.7-44.0 mg/100 mL) with mean of 1.1% (17.0 mg/100 mL). Potassium ranged from 108 to 400 mg/100 mL with a mean of 227.8 mg/100 mL. Sodium ranged from 0.2 to 4.0 mg/100 mL with a mean of 2.1 mg/100 mL. Magnesium ranged from 11.3 to 29.4 mg/100 mL with a mean of 18.6 mg/100 mL. Calcium ranged from 8.0 to 16.3 mg/100 mL with a mean of 12.5 mg/100 mL. C-13/C-12 ratios ranged from -26.0 to -21.9 parts per thousand PDB (PeeDee Belemnite) with a mean of 24.2 parts p er thousand.