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Universidade Federal de Santa Catarina (2011)

Mucilagem do cladódio de cereus hildmaniannus K. Schum

Bruzamarello Caon Branco, Natália

Titre : Mucilagem do cladódio de cereus hildmaniannus K. Schum

Auteur : Bruzamarello Caon Branco, Natália

Université de soutenance : Universidade Federal de Santa Catarina

Grade : Mestrado 2011

Sustainable natural resources of biomass that exist in many regions of the world may be used as less expensive alternatives for producing add-ed-value industrial polysaccharide gums. Among resources currently being sought for this purpose, indigenous plants from arid lands deserve special attention due to their economic and ecological advantages, such as the low input of water and energy needed for their commercial ex-ploitation. In this context, the cactus Cereus hildmaniannus K. Schum naturally grows in stony soil with lack of water. The specie is well-known by the rural population of the Midwest region of Santa Catarina State and has been important, as it presents potential for domestication and scale cultivation. This cactus presents, among several technological applications, as source of the complex carbohydrate mucilage. Mucilage has high capacity to absorb water and could be considered as a potential hydrocolloid for industrial use, such in food industry as in other areas. In this sense, this work aims to contribute to characterize this cactus in terms of its technological potential of the mucilage present in the cla-dodes. A methodology for aqueous extraction and precipitation with ethanol was proposed, which was adequate for obtaining the solid prod-uct. Fourier transform infrared, thermogravimetry, differential scanning calorimetry, X-ray diffraction, and scanning electron microscopy were employed to characterize the mucilage. The behavior of the mucilage in aqueous solution was evaluated by measuring the solubility and the pH at the point of zero charge. The rheological behavior was elucidated using unidirectional rheology in a concentric cylinders viscometer and the intrinsic viscosity of the biopolymer was measured using Cannon-Fenske glass viscometer. The results indicated that mucilage is stable until temperatures near 200 °C and has a partially crystalline structure. Herschel-Bulkley model successfully correlated data for all evaluated concentrations, except for the sample at 0.10%, which was adjusted using Bingham model. Thus, mucilage from Cereus hildmaniannus K. Schum has a non-newtonian behavior and is time-dependent (thixotrop-ic) in temperatures from 10 °C to 25 °C.

Mots clés  : Engenharia quimica ; Mucilagem ; Biopolimeros ; Reologia ; Cacto


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