Chitosan as flocculant agent for clarification of stevia extract

Abstract

Stevia is used as a sweetener due to its low calorific value and its taste, which is very similar to that of sucrose. After extraction from dried leaves, stevia extract is dark in colour, and therefore needs to be whitened to increase acceptance by consumers. In this study we tested chitosan, a cationic polyelectrolyte, as flocculant agent for the whitening of the Stevia extract. Positive charges of chitosan can interact electrostatically with a counter-ion, sodium tripolyphosphate (TPP), and then chitosan precipitates. A factorial design was used to study the whitening process, in which Glycosides Removal, Colour Removal, Turbidity Removal and Soluble Solids Removal were evaluated. The studied factors were Chitosan Mass and pH of the TPP solution. The results showed that chitosan is a good flocculant agent, being able to flocculate both the glycosides and the pigments that make the extract coloured.

Development of dual-sensitive smart polymers by grafting chitosan with poly (<italic>N</italic>-isopropylacrylamide): an overview

“…There are many polymers responsive to the environmental pH ( Figure 2), including synthetic ones, such as poly (acrylic acid), poly (2-ethyl acrylic acid), poly (N,N-diethyl aminoethyl methacrylate) and poly (vinyl imidazole) [2] , and those from natural sources, such as alginate [88,89] , carboxymethylcellulose [90,91] and chitosan [92][93][94][95][96][97] . The pH-responsive polymers can also be classified as: (i) polyacids, which contain pendant weak acid groups, such as -COOH and -SO 3 H; (ii) polybases, that possess pendant weak basic groups (-NH 2 ) in their chains [2,10] ; or (iii) polyamphoterics, that bear both weak acid and basic groups [62] .…”

Effect of Stevia rebaudiana aqueous extract and microencapsulation on the survivability of Bifidobacterium bifidum Bb‐12 and Lactobacillus acidophilus La‐5 in functional ice cream

“…After that, it was filtered twice through Whatman #4 paper, and the solid matter was removed by filtration. The extract solution was dried at 60 °C and kept at 4 °C until its use in the experiments (de Oliveira et al ., 2012).…”

Purification of stevia extract by chitosan precipitation and reversed‐phase chromatography

“…Phenolic compounds (phenols and flavonoids) could be the main phytochemicals highly responsible to the bitter taste and dark colour of the stevia extract (Kaushik et al, 2010). To solve this problem, chitosan has been used as flocculant agent for clarification of stevia extract (de Oliveira et al, 2012), and this method was considered as economic and less aggressive to environment. Water soluble proteins are also impurities in SG extract; however, removal of proteins from SG extract has not been formally reported.…”