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United States Department of Agriculture

Agricultural Research Service

Research Project: NEW TECHNOLOGIES TO PROCESS VALUE-ADDED, HEALTHY FOODS FROM FRUITS AND VEGETABLES

Location: Healthy Processed Foods Research

Title: Effect of IR Drying Temperature on the Quality of Partially Dried Fresh and Infused Blueberries

Authors
item Shi, Junling - NORTHWEST AG UNIV., CHINA
item Pan, Zhongli
item McHugh, Tara
item Hirschberg, Edward - INNOVATIVES FOODS, SF, CA

Submitted to: Proceedings for CIGR World Congress Meetings
Publication Type: Abstract Only
Publication Acceptance Date: February 16, 2007
Publication Date: N/A

Interpretive Summary: This study investigated the effectiveness of infrared (IR) heating for drying fresh and sugar-infused blueberries. The suggested optimum drying temperature was 70°C for fresh blueberries, and 80°C for infused blueberries, which resulted in a good balance of fast drying rates and good product quality.

Technical Abstract: This study investigated the effectiveness of infrared (IR) heating for drying fresh and sugar-infused blueberries. Effect of four constant drying (product) temperatures (60, 70, 80 and 90°C) on the quality of products dried for various time periods was evaluated. The evaluated quality parameters of partially dried blueberries included color, acid content and texture. Infused blueberries with a moisture content of 50% and soluble solids of 50oBrix were prepared by infusing frozen blueberries with a constant 60°Brix sucrose solution for 22h at room temperature. The control samples of dried blueberries were produced by using 60°C hot air drying. Results showed that the drying rates of blueberries were highly dependent on drying temperature. High drying temperatures resulted in faster and greater changes in color of fresh blueberries during drying. Fresh blueberries partially dried at a higher temperature had harder and more chewy textures than a lower drying temperature. Dried products from fresh blueberries became redder, more yellow and acidic with the progress of drying. The drying temperature did not show significant effects on the texture of partially-dried, sugar-infused blueberries. No significant change was found on any of the color values for infused blueberries. The suggested optimum drying temperature was 70°C for fresh blueberries, and 80°C for infused blueberries, which resulted in a good balance of fast drying rates and good product quality.

Last Modified: 4/17/2014
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