Browsing by Author "Fossen, Torgils"
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- Anthocyanin stability: a chemometrical approachPublication . Cabrita, Luís; Fossen, Torgils; Flåten, Geir R.; Andersen, Øyvind M.The stability of cyanidin 3-glucoside towards five different factors (pH, anthocyanin concentration, sodium chloride concentration, ascorbic acid concentration, Oxygen) was studied during 60 days storage at room temperature using a 2^4-1 reduced factorial design. The influence of each individual parameter on anthocyanin stability was found to vary as a function of time. Sodium chloride and ascorbic acid were, respectively, the variables most contributing to and against anthocyanin stability. Results suggest there may be some degree of interaction between anthocyanin/ascorbic acid, and between pH/Oxygen, affecting anthocyanin degradation.
- Colour and stability of pure anthocyanins in aqueous solutions at high pH valuesPublication . Andersen, Øyvind M.; Fossen, Torgils; Cabrita, LuísThis study on anthocyanin colour variation (intensity, lambda max, molar absorbptivity) over the pH range 1-9 during 60 days of storage, was conducted on petunidin 3-[6-O-(4-O-E-p-coumaroyl-O-alfa-L-rhamnopyranosyl)-beta-D-glucopyranoside]-5-O-beta-D-glucopyranoside (petanin) and cyanidin 3-O-beta-D-glucopyranoside (cy3glc) at 10 and 23ºC. Compared to cy3glc, petanin afforded higher colour intensity and higher or similar stability throughout the whole pH range. At pH 4.0, 84% of petanin was intact after 60 days storage at 10ºC, while the corresponding solution of cy3glc was totally degraded. At pH 8.1 the colour intensity of petanin was even higher than at the lowest pH values. The visible lmax absorption of petanin after 5 days at pH 8.1 at 10ºC was similar or higher than the corresponding absorptions of the fresh solutions of cy3glc at any pH. The use of anthocyanins like petanin as food colorants in slightly alkaline products (bakery, milk, egg, etc.) should therefore be considered at least in products with limited storage time kept in a refrigerator.
- Colour and stability of pure anthocyanins influenced by pH including the alkaline regionPublication . Fossen, Torgils; Cabrita, Luís; Andersen, Øyvind M.This study on anthocyanin colour variation (intensity, lambda max, absorptivity) over the pH range 1-9 during 60 days of storage, was conducted on petunidin 3-[6-O-(4-O-E-p- coumaroyl-O-alfa-L-rhamnopyranosyl)-beta-D-glucopyranoside]-5-O-beta-D-glucopyranoside (petanin) and cyanidin 3-O-beta-D-glucopyranoside (cy3glc) at 10 and 23ºC. Compared to cy3glc, petanin afforded higher colour intensity and higher or similar stability throughout the whole pH range. At pH 4.0, 84% of petanin was intact after 60 days storage at 10ºC, while the corresponding solution of cy3glc was totally degraded. At pH 8.1 the colour intensity of petanin was even higher than at the lowest pH values. The visible lambda max absorption of petanin after 5 days at pH 8.1 at 10ºC was similar or higher than the corresponding absorptions of the fresh solutions of cy3glc at any pH. The use of anthocyanins like petanin as food colorants in slightly alkaline products (bakery, milk, egg, etc.) should therefore be considered at least in products with limited storage time kept in a refrigerator.
- Colours of pure anthocyanidin 3-glucosides in aqueous solutions during storagePublication . Cabrita, Luís; Fossen, Torgils; Andersen, Øyvind M.A study on anthocyanin stability and colour variation (intensity, lambda max., molar absorptivity) during storage at 10º and 23ºC over the pH range 1-12 was conducted for the 3-glucosides of the six common anthocyanidins. These results show that some anthocyanins may provide stable and intense bluish colour for extended application in slightly alkaline food products. For instance, there are some Mexican food (varieties of 'tacos') containing anthocyanins under alkaline conditions.