Deliquescent highly soluble crystalline ingredients are prone to caking and dissolution when they are stored
above a certain relative humidity (RH) but exhibit minimal moisture adsorption below this RH. Anticaking
agents are added to improve the flowability of powders and to prevent or reduce caking. The objective of
this study was to determine the effects of anticaking agents on the moisture sorption behavior, flowability,
and caking characteristics of deliquescent ingredients and blends thereof. Single deliquescent food ingredients
(sodium chloride, sucrose, fructose, and citric acid) and binary systems (sodium chloride blended
with sucrose, fructose, or citric acid) were used as the host powders, and silicon dioxide, calcium silicate,
and calcium stearate were the three anticaking agents studied. Moisture sorption isotherms were generated
to investigate the water–solid interactions of the anticaking and host powders. Following controlled RH storage
treatments, caking was assessed by the sieve test and flowability by avalanche power and avalanche
angle measurements. Formulation had variable effects on deliquescence behavior and moisture sorption,
while formulation, storage RH, length of storage, and RH cycling all significantly affected the physical stability
of the powder blends. Calcium stearate was the most effective anticaking agent at reducing moisture sorption
and delaying the onset of deliquescence, as well as maintaining the flowability properties of all powders
tested. In particular, calcium stearate was able to substantially alter the moisture sorption behavior of blends
of deliquescent ingredients, which are inherently more susceptible to the deleterious effects of moisture due
to deliquescence lowering. The results are of great significance because they show that the effectiveness of an
anticaking agent in preventing moisture-induced caking depends on the complexity of the host powders as
well as on the interaction with environmental moisture. Thus, the type of anticaking agent added to a deliquescent
ingredient must be tailored to the host powder to enhance product quality and stability.