Tagatose Stability in Beverages as Impacted by Composition and Thermal Processing

Tagatose is a monosaccharide that contributes prebiotic characteristics to foods and beverages. Tagatose has the propensity to degrade depending upon product composition and storage environment. Intramolecular rearrangement and cleavage reactions are enhanced at higher pH levels. Citrate and phosphate buffers catalyze tagatose degradation, with the small dibasic phosphate anion being especially catalytic. Amino acids can react with tagatose via the Maillard reaction to cause browning. Degradation is accelerated by increases in temperature. The time/temperature requirements necessary for pasteurization result in tagatose losses of less than 1%. Refrigeration helps maintain at least 98% of the original tagatose concentration in beverages stored 6 mo. Stability concerns arise for shelf stable beverages containing phosphate buffer at high pH levels. Tagatose retention in beverages is improved by formulating with citrate buffer instead of phosphate buffer, reducing the buffer concentration, lowering the pH, and decreasing the storage temperature.