The impact of deliquescence and formulation on the chemical stability of vitamin C in food blends

Ashley N Hiatt, Purdue University

Abstract

Many food products are designed in powder form, such as dietary supplements, vitamin premixes, and finished dry mixes. A primary incentive for supplying products as powders is increased stability via reduced water activity and molecular mobility. However, while it is generally understood that the presence of water may have detrimental effects, knowledge of the impact of specific water-solid interactions on the stability of food powders is lacking. An improved understanding of how water will interact with ingredients in powder products is essential to ensure delivery of high value products. In this research, one of the five water-solid interactions, deliquescence, was studied in relation to chemical stability of ingredients commonly found in dietary supplements and foods, with specific emphasis on vitamin C. The overall objective of this research was to characterize the impact of deliquescence and formulation on the chemical stability of food blends containing bioactive ingredients. Deliquescence has been shown to promote chemical instability, which was further demonstrated in this research for vitamins in vitamin and sugar blends. The relationship between deliquescence behavior and chemical stability was explored further using select forms of vitamin C that differ in solubility. Vitamin stability was significantly reduced once the deliquescence poiont was exceeded. Shelf-life studies were conducted by storing two forms of vitamin C at various relative humidity and temperature conditions to better understand the effect of phase transformations, such as deliquescence, on shelf-life model construction. Temperature enhanced vitamin solubility, thus reducing the deliquescence point and stability. Additional investigations were designed to improve understanding of the effect of co-formulated ingredient phase transitions on vitamin C stability by exposing blends of vitamin C and an amorphous ingredient to various relative humidities. It was shown that deliquescence significantly affected moisture uptake and vitamin degradation, and the importance of considering specific ingredients will impact moisture sorption and subsequent delivery of vitamin C was highlighted. Other ingredient interactions likely enabled by the deliquescence process were studied in mixtures of select bioactive compounds with ascorbate. At high RH and in the presence of bioactive ingredients, ascorbate degradation was enhanced. This body of work emphasizes the importance of careful consideration of ingredient solubility, moisture-mediated reactions, and storage RH when designing powder formulations containing vitamin or bioactive ingredients and for subsequent estimations of stability.

Degree

Ph.D.

Advisors

Mauer, Purdue University.

Subject Area

Food Science

COinS