M. Monica Giusti

Acylated anthocyanins from edible sources and their applications in food systems

Abstract There is considerable demand for food colorants from natural sources that can serve as alternatives to the use of synthetic dyes due to both legislative action and consumer concerns over the use of synthetic additives. Interest in anthocyanin-rich foods and extracts has intensified because of their possible health benefits. Anthocyanins are potent antioxidants and may be chemoprotective. Optimizing health and performance through the diet is believed to be one of the largest and most lucrative markets in the US, and throughout the world. Findings of acylated anthocyanins with increased stability have shown that these pigments may impart desirable color and stability for commercial food products. Examples of suitable acylated anthocyanin sources may be radishes, red potatoes, red cabbage, black carrots, and purple sweet potatoes. Among these, radishes and red potatoes stand out as potential alternatives for the use of FD&C Red No. 40 (allura red). Maraschino cherries with bright attractive and stable red color were obtained with radish extract. Radish and potato extracts imparted color characteristics to model juices extremely close to those of allura red. Other potential applications for acylated anthocyanins may include other challenging systems such as dairy products. The increased stability of these pigments together with their added value due to potential beneficial effects opens a new window of opportunities for use of these extracts in a variety of food applications.

Anthocyanins from Oxalis triangularis as potential food colorants

Abstract Anthocyanin pigment content and profile from Oxalis triangularis (oxalis) was investigated for the first time. The pigments were extracted, purified using C-18 resin and characterized by HPLC, UV-visible spectral analysis, physicochemical reactions, and mass spectrometry before and after alkaline and acid hydrolysis. Monomeric anthocyanin content was 195 mg/100 g leaves on malvidin-3,5-diglucoside basis. Colour characteristics of a pH 3.5 oxalis anthocyanin extract (optical density of 0.3, 520 nm) were 86.0, 9.8 and 8.0 for Hunter CIE L *, hue angle and chroma, respectively. Three anthocyanins represented 90% of the total peak area obtained by HPLC. The major anthocyanin was malvidin-3-rutinoside-5-glucoside and the others were acylated derivatives containing one and two molecules of malonic acid esterified to the main structure. The attractive hue, high anthocyanin content and edible character of O. triangularis make it a potential desirable source of natural colorant.

Anthocyanins from banana bracts (Musa X paradisiaca) as potential food colorants

Banana (Musa X paradisiaca) bracts, abundant edible residues of banana production, were investigated as a potential source of natural colorant. Anthocyanins were extracted with acidified methanol, purified using C-18 resin, and characterized by UV-visible spectroscopy, physicochemical reactions, HPLC, and electrospray mass spectrometry. Monomeric anthocyanin content was 32.3 mg/100 g bracts on a cyanidin-3-rutinoside basis. Color characteristics (Hunter CIE L*hc) of a solution (absorbance of 0.3, 520 nm, pH 3.5), were L*=86.8, h=44.2 and c=12.7. Cyanidin-3-rutinoside represented ∼80% of the total pigment. Other anthocyanins were 3-rutinoside derivatives of delphinidin, pelargonidin, peonidin and malvidin. One acylated anthocyanin (∼2% of the pigment) was found but not identified. Acid hydrolysis of anthocyanins revealed the concomitant presence of six more common anthocyanidins (delphinidin, cyanidin, petunidin, pelargonidin, peonidin and malvidin) suggesting that, besides being a good pigment source, it could also be a useful tool for anthocyanin identification.