PIGMENT REMOVAL AND PECTIN LOSS DURING THE CONTINUOUS, COUNTERCURRENTWASHING OF SUNFLOWER HEADS

Sunflower heads are a promising source of pectin which is naturally lo w in methoxyl groups. As a pretreatment before pectin extraction, the heads must be washed with water to remove pigments and other impuritie s. Previous washing studies were limited to small (less than or equal to 100 g) single-stage batch tests. The objective of this study was to analyze the effects of temperature or water-to-solids ratio on pigmen t removal and on pectin loss in a bench-scale continuous, countercurre nt washing unit. Temperature and water-to-solids ratio ranged from 45 to 75 degrees C and 12 to 35 g/g, respectively. The solids flow rate w as 4.6 g/min and solids residence time was 15 min. The relationship of pigment removal to water-to-solids ratio was fitted to a nonlinear eq uation by least squares. Continuous washing conditions were identified which consumed less water yet achieved more pigment removal compared to batch washing. Thus, continuous washing should reduce wastewater tr eatment costs.