Compositional, spectroscopic and rheological analyses of mucilage isolated from taro (Colocasia esculenta L. Schott) corms

Abstract

Tropical roots and tubers generally contain mucilage. These mucilages exhibit unique rheological properties with considerable potential as a food thickener and stabilizer. A one-step extraction procedure was used to isolate starch free mucilage and associated proteins from a number of taro (Colocasia esculenta) varieties. The monosaccharide and amino acid composition, the structural and flow properties were investigated. The results showed that yield of mucilage fraction varied from 30 to 190 g.kg(-1). A negative correlation (r = -0.87; p < 0.05) was observed between the crude protein level and the yield. The monosaccharide profiles revealed that galactose, mannose and arabinose were the main monosaccharides in the hydrolysate of the mucilage. From the 17 amino acids analyzed, aspartic acid/asparagine (14.4-17.2%) and glutamic acid/glutamine (10.3-13.6%) were prominent in the mucilage as well as the flour. No significant differences were observed in the FT-IR spectra and in the viscosity behavior of the mucilage dispersions. The greatest difference in the mucilage is based on its monosaccharide profile while the protein composition, which reflects that of the flour, is relatively stable.

Chemical composition, functional and sensory characteristics of wheat-taro composite flours and biscuits

“…This suggested a positive interaction between the soluble protein (mostly mucilage in the case of taro, Njintang et al 2011) in raw taro flour favourable to emulsion formation which is degraded in pre-boiled taro flour, but this needs to be investigated. Indeed, the emulsion and foaming of flours are often attributed to proteins which has always been associated with formation of cohesive interfacial film around the air/or oil and water in the mixture system (Njintang et al 2001;Kaur et al 2011).…”

“…The most important producers are Nigeria (58 %), Ghana (17 %) and Cameroon (11 %). The corms are low in fat (0.5-1.2 %), proteins (2.9-4.6 %) and vitamins, but are a good source of carbohydrates (90.8-95.5 %) and minerals (1.6-5.5 %) especially magnesium (32.9-382 mg/100 g), calcium (25.4-192 mg/100 g) and potassium (3.5-59.7 mg/100 g) (Aboubakar et al 2008;Kaur et al 2011;Njintang et al 2011). In some areas of the world taro constitutes the main food source; for instance in Palao, Micronesia, taro contributes to about 16 % of the caloric intake (Nip 1997).…”

“…Taro starch is highly digestible and has been shown to be useful in the formulation of infant foods (Nip 1997). Besides its importance as a food source, taro contains high levels of gum, which has also been shown to play a role in the reduction of high blood pressure, in hypercholesterolemia and in the management of diabetes (Njintang et al 2011).…”

Optimization of taro mucilage and fat levels in sliced breads

“…Mucilage, or gum, is generally present in tropical roots and tubers and is particularly abundant in taro. Mucilage has unique rheological properties and holds much potential for use as a food thickener and stabilizer (Njintang et al 2011;Kaushal et al 2013). This natural plant gum also produces gelling effects and increases viscosity (Fedeniuk and Biliaderis 1994).…”

“…Chemically, mucilage consists of water, pectins, sugars, and organic acids (Misaki et al 1972). In a study investigating mucilage from six different taro varieties, Njintang et al (2011) reported that the carbohydrate content of the mucilage ranged from 46 to 69 %; thus, carbohydrates were found to represent the major component of taro mucilage, and galactose, mannose and arabinose were identified as the major monosaccharides. Between 30 and 50 % of the mucilage content was protein, and aspartic acid, glutamic acid, glutamine, glycine, leucine, serine, and alanine were the most common amino acids.…”