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|Title: ||Characterization of chitosan intended to develop antimicrobial films: Microscopical Studies|
|Authors: ||Lago, M.A.|
Rodríguez-Bernaldo de Quirós, A.
Soto Valdez, H.
|Keywords: ||Segurança Alimentar|
|Issue Date: ||Jun-2012|
|Publisher: ||Instituto Nacional de Saúde Doutor Ricardo Jorge, IP|
|Abstract: ||Accumulation of organic wastes in intensive crustaceans culture ponds and nearby coastal waters has become a serious environmental and economical problem. For this reason, new ecofriendly and economically feasible products from agricultural wastes or byproducts for shrimp farms have been developed. This biowaste could be used as an important source of the useful biopolymer chitin and others components such as proteins or carotenoids like asthaxanthin .
Chitin is the most abundant polysaccharide after cellulose and the main source is the shell of crustaceans. Chitosan, derived from chitin, has proven useful for a wide range of applications due to its biodegradability, biocompatibility, antimicrobial activity, non-toxicity and versatile physicochemical properties. These properties make the chitosan an excellent candidate to use in food packaging .
The development of active packaging with antimicrobial and antioxidant activity based on chitosan and asthaxanthin obtained from shrimp waste is the main goal of the project: “Preparation of active packaging with antioxidant and antimicrobial activity based on asthaxanthin and chitosan” funded by FONCYCIT.
The characterization of chitosan in the development of active materials is a key issue since their properties play an important role in its effectiveness as an antimicrobial agent. These properties are mainly molecular weight (Mw), acetylation degree (DA) and polymerization degree (PA). In addition, in mediums of low pH, the antimicrobial activity of chitosan increases .
The objective of the present study was characterized three different samples of chitosan obtained from shrimp waste by using two microscopy techniques, Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Additionally, the films developed after the chitosan incorporation in the polyamide matrix were also characterized.
Shrimp waste (heads and cephalotorax) samples were collected from local shrimp processing factories in South Sonora, Mexico. The waste was minced, fermented and centrifuged. After the treatment, three fractions were obtained: chitin-rich fraction, protein rich liquor and lipid fraction.
Scanning Electron Microscopy was used to investigate the structure properties relationships of chitosan. Samples were spread on a carbon conducting adhesive tape pasted on a metallic stub, subjected to gold covering and observed.
The samples for TEM observation were embedded in EPON resin and polymerized at 60 ºC; then were cut at (-120 ºC) using a Leica Ultracut crio-ultramicrotome. The images obtained showed the particle of chitosan embedded into the polyamide matrix.|
|Peer Reviewed: ||yes|
|Appears in Collections:||DAN - Posters/abstracts em congressos internacionais|
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