Moisture-Mediated Interactions Between Amorphous Maltodextrins and Crystalline Fructose.

The effects of coformulating amorphous maltodextrins (MDs) and crystalline fructose, a deliquescent solid, on the moisture sorption, deliquescence point (RH0 ), and glass transition temperature (Tg ) behaviors were determined. Moisture sorption profiles of binary fructose:MD mixtures and individual ingredients were generated using controlled relative humidity (RH) desiccators and by dynamic vapor sorption techniques. Blends exhibited synergistic moisture uptake at RHs below the RH0 of fructose, attributed to partial dissolution of fructose in plasticized MD matrices without a significant reduction in the RH0 of the undissolved fructose. Increasing storage temperature decreased the onset RH for moisture sorption synergy. At all storage RHs, the measured Tg (2nd scan) was significantly reduced in fructose:MD mixtures compared to individual MDs, and was related to both the synergistic moisture uptake in the blends and heat-induced ternary fructose-MD-water interactions in the differential scanning calorimeter. Differences were found between the behavior of fructose:MD blends and previous reports of sucrose:MD and NaCl:MD blends, caused in part by the lower RH0 of fructose. The enhanced moisture sorption in blends of deliquescent and amorphous ingredients could lead to problematic moisture-induced changes if storage conditions are not controlled.

Water-solid interactions between amorphous maltodextrins and crystalline sodium chloride.

The effects of co-formulating amorphous maltodextrins (MDs) and sodium chloride (NaCl), a deliquescent crystalline solid, on moisture sorption, deliquescence point (RH0), and glass transition temperature (Tg) behaviours were investigated. Moisture sorption profiles of binary NaCl:MD mixtures and individual ingredients were generated using controlled relative humidity (RH) desiccators at temperatures from 22 to 50°C and by dynamic vapour sorption (DVS) and dynamic dewpoint sorption (DDS) techniques. Close proximity of MD and NaCl induced synergistic moisture uptake in binary mixtures above a threshold RH, resulting in significantly lower Tgs in binary mixtures compared to individual MDs. The RH0 of NaCl was also lower in the blends. Mixing amorphous MD with crystalline NaCl resulted in synergistic moisture sorption and reduced both Tg and RH0, thus blends were more sensitive to environmental moisture than the individual solids. This has implications for quality control of many formulated powder products.