Effect of Concentration on the Physicochemical and Rheological Properties of Grapefruit Juice (Citrus paradise)

Grapefruit, like other vegetables and citrus fruits, grows during certain seasons of the years. Grapefruit juice has a therapeutic effect. Water content of grapefruit is about 80 to 90. The concentration of the grapefruit juice is the most economic processing method. In the current study, the effect of concentration on the physicochemical properties and rheological characteristics of concentrated grapefruit juice at several Brix were investigated.
Grapefruit (Duncan varieties) was purchased from local markets. After juice extraction, the grapefruit juice was concentrated using vacuum rotary evaporator (60 °C and 60 rpm) in several °Brix (9.5, 22, 34.5, 47, and 59.5). Soluble solids (°Brix), pH, density, opacity, color parameters and rheological properties of the samples were measured.
pH value of the fresh juice was 2.77±0.07 (Brix 9.5), which reduced to 2.26±0.05 (°Brix 59.5) after concentration (p