METHOD OF CASHEW TREE GUM PURIFICATION

METHOD OF CASHEW TREE GUM PURIFICATION: EFFECT OF INITIAL CONCENTRATION
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Bruna Castro Porto , Antônio Calixto Lima², Henriette Monteiro Cordeiro de Azeredo², Marcelo
Cristianini¹, ¹School of Food Engineering, University of Campinas - UNICAMP, Rua Monteiro
Lobato 80, 13083-862 Campinas, São Paulo, Brazil. ²Brazilian Agricultural Research
Corporation – EMBRAPA, Rua Dra. Sara Mesquita 2270, 60511-110, Fortaleza, Ceará, Brazil.
Methods for polyelectrolytes isolation use 4 % of material in the dissolution, separation by
filtration and sedimentation, generating large amounts of waste, cost, process time and yield
loss. Therefore, this work aimed to optimize the method for cashew tree gum purification. Crude
gum (exudate) was dispersed at 4 and 10 % concentrations for 24h at 23 °C (pH 7). The
solution was then filtered through a sieve and centrifuged at 10,000 rpm/5 min at 10 °C for
impurities separating. The supernatant was precipitated in ethanol INPM 92.8 at 15 °C in a 1:1.5
supernatant/ethanol ratio. The new supernatant was centrifuged at 5000 rpm/5 min and the
precipitate obtained as above incorporated. The isolated gum was placed in trays and dried in
an air circulation oven at 50 °C/24h and weighed to define the yield. Process was carried out in
duplicate and samples were carried out in triplicate. The results were evaluated by ANOVA. The
yields obtained at 4 % (55 %) and 10 % (59 %) concentrations were not different (p<0.05). The
raw material heterogeneity, presence of bark, dust and insects were partially responsible for the
low yield of gum. Using a higher initial concentration of the crude gum did not alter significantly
the yield, leading to a significant reduction in ethanol consumption and consequently a lower
waste, as well as a faster and less expensive process.