Stability and degradation kinetics of crude anthocyanin extracts from H. sabdariffa

Abstract

Hibiscus sabdariffa is an under-utilized plant that has reported to have great potential in the food industry. The vibrant red pigment from the calyces indicate a source of anthocyanins. Anthocyanins would make ideal natural food colourants with additional nutritional benefits however stability is a hindering factor. Stability studies were the main focus of this study. Crude anthocyanins were extracted using four different solvent systems. The crude extracts were analysed under the following parameters; heat (50 and 80 °C), light (darkness and 20 W light) and pH (pH 1-9) stability. Degradation kinetic studies were done on thermally treated samples. Radical scavenging ability was thereafter calculated. Anthocyanidins were identified and quantified by HPLC coupled with a Diode Array Detector (DAD). Total phenolic content was determined with Folin -Ciocalteu's method. Approximately 87% of pigments were retained when heated at 50 °C while heating at 80 °C resulted in 61% pigment retention. The pH stability of samples incubated for 7 days indicated that crude anthocyanins degraded slower at acidic pH. Light stability showed slower degradation in dark incubated samples resulting in 84% pigment retention after a 10 day period. H. sabdariffa shows potential for the application of a food in products such as jelly and yoghurt.

Physicochemical Properties and Antimicrobial Effects of Roselle Corolla, Onion Peels and Peanut Skins Anthocyanins

“…The highest yield of anthocyanin was observed in roselle corolla extracted by distilled water (27.43 mg/100g). These results agree with those reported by (Mattuk, 1998;Sipahli et al, 2017).…”

“…The plant is described as being red stemmed with serrated leaves and red corolla. Although H. sabdariffa is termed an under-utilized crop, it is used commonly in households for its traditional medicinal properties and produced into various edible products such as jam, jelly and tea (Sipahli et al, 2017). H. sabdariffa is known for its various pharmaceutical, nutritional and traditional medicinal properties and has said to be a rich source of anthocyanins ( Patel, 2014).…”

“…Anthocyanins would make ideal natural food colourants with additional nutritional benefits however stability is a hindering factor (Sipahli et al, 2017). In view of the stability, the aim of the present study was to investigate the physicochemical properties, antibacterial and antifungal effects of the major anthocyanins extracted from roselle corolla, onion outer peels or peanut skins.…”

Anthocyanin as Natural Colorant: A Review

“…However, it can also be dissolved in polar organic solvents such as ethanol, methanol, acetone, and chloroform (Kristiana et al, 2012). Anthocyanin is very stable in acidic conditions, so that when extraction can be added organic acids such as acetic acid, citric acid, or hydrochloric acid (Sipahli et al, 2017).…”

Development and optimization of microparticles containing a hypoglycemic fraction of calyces from Physalis peruviana

“…In spite of the pharmacological properties of the vegetable extracts, some environmental and systemic condition could degrade the active metabolites of several extracts (Goppel and Franz, 2004;Thakur et al, 2011;Sipahli et al, 2017), mainly O-glycosylated flavonoids as rutin (Plaza et al, 2014). For this reason, microencapsulation has been employed for several vegetable extracts since this technique allows a target delivery, protection from enzymes or hydrolytic pHs, masking bitter tastes and improve extracts stability (Singh et al, 2010;Fang and Bhandari, 2010;Santos et al, 2017;Massoung-Bora et al, 2018) resulting in an improvement of the biological activity.…”