Production of pyranoanthocyanin pigments from cyanidin-derivatives with different glycosylation patterns for food colorant use
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Publisher:The Ohio State University
Series/Report no.:The Ohio State University. Department of Food Science and Technology Undergraduate Research Theses; 2017
Traditionally synthetic colorants have been used in food to ensure vibrant and stable colors, but as consumer acceptance decreases and health concerns over synthetic colorants arise, natural colorant use has increased. Anthocyanins (ACN) are natural colorants with limited stability. Pyranoanthocyanins (PACN) are recently discovered, anthocyanin-derived compounds that have increased stability and could function as safe natural food colorants. However, the conversion of the ACN to PACN is not well understood, limiting commercial food application. The purpose of this study was to understand how ACN chemical structure affects PACN formation. It was hypothesized that ACNs possessing more than two sugar moieties would have no PACN formation due to steric hindrance. Cyanidin-3-glucoside, Cyanidin-3,5-diglucoside, Cyanidin-3-galactoside, Cyanidin-3-glucoside-galactoside and Cyanidin-3-xyloside-glucoside-galactoside were isolated from plant sources and purified to test how location, type and number of sugar moieties affected PACN formation. Samples were combined with pyruvic acid and stored at 35℃ in pH 2.5 buffer. A HPLC-PDA was used to generate a chromatogram on day 0, 10 and 20. Spectral and color data were obtained on day 0 and 20. On day 20, all Cyanidin-3-glycosides showed PACN formation. The proportion of PACNs to total pigment ranged from 6.4% (Cyanidin-3-glucoside-galactoside) to 40.3% (Cyanidin-3-glucoside). Cyanidin-3,5-diglucoside experienced extensive pigment degradation by day 10 and had no PACN formation indicating pyruvic acid access to C5 on the ACN molecule is essential for PACN formation. A hypsochromic shift in the lambda maximum occurred in all samples ranging from 1.6-11.3 nm. A larger shift indicated more PACN formation. Preliminary data indicates C3 monoglycoside ACNs formed PACNs most efficiently, and the larger the substitution the less PACNs formed. ACN structural characteristics are an important parameter when optimizing PACN formation. Efficient production of PACNs could allow for a more stable naturally derived pigment for food industry use.
1st Place at the CFAES Undergraduate Research Forum
Academic Major: Food Science and Technology
Food Science Undergraduate Research Experience