ARS | Publication request: Comparison of Different Formulations for Cranberry Phenolic Retention during Radiant Zone Drying

Submitted to: Annual Meeting of the Institute of Food Technologists
Publication Type: Abstract Only
Publication Acceptance Date: February 18, 2010
Publication Date: July 17, 2010
Citation: Subramanian, A., Lee, J., Ringer, K.L., Savarese, M. 2010. Comparison of different formulations for cranberry phenolic retention during radiant zone drying. Annual Meeting of the Institute of Food Technologists. IFT National Meeting Book of Abstracts. Abstract 233-10.

Technical Abstract: Novel dehydration methods to efficiently produce high quality small fruit powders for ingredients and nutritional supplements are in demand. Radiant zone drying (RZD) has recently received attention as a potential cost-effective alternative to freeze-drying or spray-drying. It is essential to understand its effect on berry phenolics and optimize formulations to improve final product quality and production efficiency. The effect of RZD on phenolics in different formulations of cranberry juice concentrates and purées was investigated. Three different formulations each of juice concentrate (a- pH adjustment with magnesium hydroxide to 7.0 followed by citric acid to 3.0, b- pH adjustment to 3.5 with magnesium hydroxide, and c- addition of 20% carrier) and purées (a- addition of 2% silicon dioxide during drying, b- addition of 10% carrier, and c- addition of 40% carrier) were dried to powders by RZD. Total phenolics (Folin-Ciocalteau), total tannins (methylcellulose precipitation), total anthocyanins (pH differential), individual anthocyanins (HPLC), color (L*a*b*, chroma, and hue angle), and moisture were determined. Phenolics in RZD powders were compared to juice concentrate and purée (starting material). RZD powders from juice concentrate with 20% carrier and purée with 40% carrier exhibited highest phenolics retention, possibly due to shorter drying time. In general, little or no significant reduction was observed in total phenolics, total anthocyanins, and six individual anthocyanin concentrations. Total tannins decreased significantly during drying. RZD powders (as-is) from juice concentrate adjusted to pH 3.5 with magnesium hydroxide and purée with 2% silicon dioxide contained the highest amount of phenolics. The results suggest that radiant zone drying with its advantages such as improved dehydration temperature control, process efficiency, and reduction of carrier amount needed could be an alternative method for high quality fruit powder production.