Characterization of chitosan. Influence of ionic strength and degree of acetylation on chain expansion

Rinaudo, Marguerite; Milas, M.; Dung, Pham Le

doi:10.1016/0141-8130(93)90027-j

Cited by 489 publications

(308 citation statements)

References 18 publications

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“…The oil content was determined using the Ether Extract Method B. The MW of each COS sample were verified using viscometry, which is a simple and rapid method for the determination of MW (Rinaudo et al, 1993). The GE was determined using a Parr 1201 oxygen bomb calorimeter (Parr, Moline, IL, USA).…”

Section: Experimental Dietsmentioning

confidence: 99%

The effects of supplementing varying molecular weights of chitooligosaccharide on performance, selected microbial populations and nutrient digestibility in the weaned pig

Walsh

Sweeney

Bahar

et al. 2013

Animal

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An experiment (complete randomised design) was conducted to investigate the effects of supplementing different molecular weights (MW) of chitooligosaccharide (COS) on pig performance, selected microbial populations and nutrient digestibility post-weaning. A total of 396 weaned piglets (24 days of age, 7.3 kg 6 (s.d.) 1.7 kg live weight) were assigned to one of six dietary treatments (22 replicates/ treatment) for a 33-day experimental period. The dietary treatments were as follows (1) control diet (0 ppm COS), (2) control diet plus ,1 kDa COS, (3) control diet plus 3 to 5 kDa COS, (4) control diet plus 5 to 10 kDa COS, (5) control diet plus 10 to 50 kDa COS and (6) control diet plus 50 to 100 kDa COS. The COS were included at 250 ppm in the diets. There was no significant effect of dietary treatment on piglet performance during the starter period (days 0 to 18; P . 0.05). However, there were quadratic responses in both daily gain (P , 0.05) and gain to feed ratio (P , 0.05) to the increased MW of COS inclusion during the weaner period (days 18 to 33) with all COS-supplemented treatments improving daily gain and gain to feed ratio compared with the control. There was a quadratic response in faecal scoring to the increased MW of COS inclusion from days 0 to 7 (P , 0.001), days 7 to 14 (P , 0.001) and during the overall experimental period (P , 0.01) with all the COS-supplemented treatments having an improved faecal score compared with the control. During the weaner period, there was a cubic response in lactic acid bacteria and Escherichia coli populations as the MW of COS increased (P , 0.05). The 5 to 10 kDa and 10 to 50 kDa COS increased lactic acid bacteria populations compared with the control, whereas lactic acid bacteria populations decreased at 50 to 100 kDa. The 5 to 10 kDa, 10 to 50 kDa and 50 to 100 kDa COS decreased E. coli populations compared with the control. There was a cubic response in the apparent total tract digestibility of dry matter (DM; P , 0.01), organic matter (OM; P , 0.01), ash (P , 0.01), nitrogen (N; P , 0.01) and gross energy (GE; P , 0.01) to the increased MW of COS inclusion during the weaner period. The 5 to 10 kDa COS had a higher apparent total tract digestibility of DM, OM, ash, N and GE in comparison to the control, whereas the apparent total tract nutrient digestibility of these nutrients decreased at 10 to 50 kDa. The current results indicate that the MW ranges of 5 to 10 kDa and 10 to 50 kDa COS decreased E. coli numbers while increasing nutrient digestibility of the diets.

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Section: Experimental Dietsmentioning

confidence: 99%

The effects of supplementing varying molecular weights of chitooligosaccharide on performance, selected microbial populations and nutrient digestibility in the weaned pig

Walsh

Sweeney

Bahar

et al. 2013

Animal

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“…onde, [h] = viscosidade intrínseca, que foi obtida pela extrapolação à diluição infinita da curva de viscosidade reduzida versus concentração, e K e a são constantes com valores 18 de 0,0074 e 0,76, respectivamente.…”

Section: Quitosanaunclassified

Obtenção e caracterização de blendas colágeno-quitosana

Tonhi¹,

Plepis²

2002

Quím. Nova

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Recebido em 15/8/01; aceito em 19/2/02 PREPARATION AND CHARACTERIZATION OF COLLAGEN-CHITOSAN BLENDS. Biodegradable polymer blends were obtained using collagen and chitosan. Membranes of collagen and chitosan in different proportions (3:1, 1:1 and 1:3) were prepared by mixing their acetate solutions (pH 3.5) at room temperature. The blends were characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier Transform infrared (FTIR) spectroscopy, specific viscosity, water absorption and stress-strain assays. The results showed that chitosan did not interfere in the structural arrangement of the collagen triple helix and the properties of the blends can be controlled by varing the proportion of the collagen and the chitosan.Keywords: blends; collagen; chitosan. INTRODUÇÃOO colágeno é uma proteína fibrosa presente na pele, tendões, ossos, dentes, vasos sangüíneos, intestinos e cartilagens, correspondendo a 30% da proteína total e a 6% em peso do corpo humano.A quitosana é um copolímero constituído de b-(1-4)-2-amino-2-deoxi-D-glicopiranose e b-(1-4)-2-acetamida-2-deoxi-D-glicopiranose, proveniente da reação de desacetilação da quitina, o segundo polissacarídeo mais abundante na natureza.O colágeno e a quitosana têm sido bastante utilizados na medicina, odontologia e farmacologia como biomateriais, pois são polímeros biocompatíveis, atóxicos e biodegradáveis, além de possuírem inú-meras propriedades biológicas [1][2][3][4][5][6] . As blendas poliméricas constituem-se na mistura de pelo menos dois polímeros ou copolímeros sem que haja qualquer reação quími-ca entre eles 7 . O interesse nesta área deve-se às crescentes aplicações práticas destes novos materiais e os principais estudos são voltados para a melhoria de suas propriedades físicas, físico-químicas e de processamento destes materiais, comparadas às propriedades dos polímeros puros 8 . Muitas blendas formadas pela combinação de biopolímeros, têm grande importância na área de biomateriais, sendo que é possível juntar as propriedades individuais de cada material em um só, além da possibilidade de melhorar ou controlar as suas propriedades mecânicas e biológicas através da interação entre as suas estruturas quí-micas diferentes. Recentemente, membranas e hidrogéis provenientes da mistura de colágeno e quitosana foram investigados pelas suas aplicações potenciais no campo dos biomateriais 9,10 . Já foi demostrado que as interações entre o colágeno e a quitosana dependem da organização estrutural do colágeno e da quantidade e distribuição de cargas ao longo das cadeias dos dois polímeros 11 . Estas propriedades estão diretamente relacionadas com o pH do meio, que é uma propriedade de fundamental importância para o estudo da interação entre eles em solução.Este trabalho teve por objetivos obter blendas colágeno-quitosana em diferentes proporções (3:1, 1:1 e 1:3) em pH 3,5, estudar a interação entre estes dois biopolímeros tanto na forma de membranas como em solução e avaliar suas propriedades físico-químicas. PARTE EXPERIMENTAL C...

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“…For chitosan, a copolymer of (1f4)-2-amino-2-deoxy--D-glucan and (1f4)-2-acetamido-2-deoxy--D-glucan, L p o values ranging from 4.6 to 40 nm have been reported. [39][40][41][42][43][44] The value of 6 nm found at pH 4.5 with degrees of acetylation (DA) up to 55% may be considered as the most reliable one since those studies 39 take into account the polydispersity of the system and the effects of excluded-volume. The value for PDADMAC is more certain: 2.5 nm in 0.5 M NaCl.…”

Section: Introductionmentioning

confidence: 99%

Role of Polyelectrolyte Persistence Length in the Binding of Oppositely Charged Micelles, Dendrimers, and Protein to Chitosan and Poly(dimethyldiallyammonium chloride)

2005

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The effect of polyelectrolyte chain flexibility on adsorption to oppositely charged colloidal particles and its parametrization by persistence length have been investigated by comparison of PDADMAC and chitosan, polycations of equal linear charge density but of respectively low and high bare persistence lengths, relatively. Their relative affinity to (i) nonionic/anionic mixed micelles, (ii) carboxyl-terminated dendrimers, and (iii) bovine serum albumin (BSA) was studied by turbidimetric titrations. Potentiometric titrations and dynamic light scattering experiments as well as molecular modeling with SPARTAN were used to characterize and model these systems. The experimental and modeling results lead to the conclusion that while chain stiffness does influence the binding of polyelectrolytes to oppositely charged colloids, the persistence length is not necessarily an appropriate measure of chain flexibility on short length scales.

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Characterization of chitosan. Influence of ionic strength and degree of acetylation on chain expansion

Cited by 489 publications

References 18 publications

The effects of supplementing varying molecular weights of chitooligosaccharide on performance, selected microbial populations and nutrient digestibility in the weaned pig

The effects of supplementing varying molecular weights of chitooligosaccharide on performance, selected microbial populations and nutrient digestibility in the weaned pig

Obtenção e caracterização de blendas colágeno-quitosana

Role of Polyelectrolyte Persistence Length in the Binding of Oppositely Charged Micelles, Dendrimers, and Protein to Chitosan and Poly(dimethyldiallyammonium chloride)

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