Deliquescence in multicomponent food systems
The presence of water in dry or powder food systems may have undesirable effects on physical and chemical properties and product stability. There are five mechanisms of water-solid interactions. The present study was related to deliquescence, the process whereby a crystalline solid undergoes dissolution due to condensation of water vapor onto it. Solids that undergo deliquescence are commonly present in food formulations. Because deliquescence plays an important role in promoting degradation of food ingredients and blends exposed to environmental moisture, the understanding of this phenomenon is of great importance to the food industry. The goal of the research was to investigate deliquescence and its effects on the physical and chemical stability of food ingredients and multicomponent blends. The deliquescence relative humidity (RHo) of several ingredients and their mixtures (RHomix) were determined. It was observed that blends of deliquescent ingredients underwent deliquescence lowering, where dissolution proceeded at lower RHs than the RHos of any of the individual components. Presence of certain non-deliquescent ingredients promoted other moisture-induced phase transformations that significantly impacted the physical and flow properties of the products as well as the chemical integrity and bioactivity of some of the ingredients (e.g. ascorbic acid and catechins). Addition of selected components such as calcium stearate and stearic acid offered a protective effect against deliquescence and loss of powder flowability. The results presented here demonstrated that interaction of food ingredients and environmental moisture can lead to unwanted degradation at lower RHs than expected and highlight the importance of considering the complex interplay between a multicomponent system and its environment. This information may be used as an approach to understand the effects of deliquescence and to design conditions of formulation, processing, and ingredient selection with the aim of better preserving the optimum characteristics of food powders.
Mauer, Purdue University.
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