Nonenzymatic Browning of Freeze-Dried Sucrose



    1. Author Flink is affiliated with the Dept. for the Technology of Plant Food Products, Royal Veterinary and Agricultural Univ., Copenhagen, Denmark.
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The appearance of nonenzymatic browning products in sucrosebased systems (5-20%; pH 1-5) during freeze drying and during subsequent room temperature storage in the dry state was investigated. Results showed that following the completion of the primary sublimation stage of drying, sucrose hydrolysis to glucose and fructose was initiated. Glucose and fructose undergo further breakdown, and at the same time products which absorb in the UV (280 nm) were formed. A short time later observable brown colors are noted (absorbance at 400 nm). The extent of UV absorbance and brown color formation increased with decreasing sucrose concentration and decreasing pH in the initial solution.