39C-12

B. WANG¹, Y. L. Xiong, and C. Wang. (1) Department of Animal Sciences, University of Kentucky, 206 Garrigus Building, Lexington, KY 40546

JUSTIFICATION: Flavor is the major concern for people who want to consumer soymilk. The Cornell and Illinois methods have dramatically reduced the beany flavor of soymilk. However, many commercial soymilks have been subjected to intense thermal treatment. Although this process has extended its shelf life to more than 6 months at room temperature, it also impairs the flavor and color of soymilk. We hypothesized that pasteurization combined with refrigeration might be sufficient to preserve soymilk and maintain its desirable flavor.

OBJECTIVES: This study was to establish procedures to improve flavor, stability, and acceptability of soymilk subjected to pasteurization and refrigeration storage.

METHOD: Soymilk was extracted essentially following the Illinois method. After the residues were removed by centrifugation, the liquid was collected and used to formulate flavored soymilk with sucrose, chocolate, almond, and vanilla flavor. After bottling and pasteurization, the soymilk was stored at 3°C for 1, 14, and 28 days. The sensory, rheological properties, as well as microbial populations of the soymilk were measured at the designated times.

RESULTS: The soymilk contained 85.7% moisture, 10.5% carbohydrates and ash, 2.2% protein, and 1.6% fat. Flavored soymilk had 18% higher panel scores in aroma than plain soymilk. All the soymilks had <10 CFU/mL for total aerobic, colifrom, and E. coli counts. After one month storage, TBARS content in the soymilk decreased by 20%. Addition of 0.05% iota-carageenan increased the viscosity of soymilk from 0.01Pas to 0.04 Pas and partially masked the beany flavor and off flavor. Overall, the flavored soymilk had higher sensory scores in desirable characters and lower scores in undesirable characters than the plain soymilk.

SIGNIFICANCE: Chocolate, almond, and vanilla flavor can enhance the aroma and reduce the off-flavor and beany flavor of soymilk. The improved flavor together with the adequate stability may render the soymilk readily acceptable to the general American consumers.