89B-26 |
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K. NADARAJAH1, W. Prinyawiwatkul1, and H. K. No2. (1) Dept. of Food Science, Louisiana State Univ. Agricultural Center, Baton Rouge, LA 70803-4200, (2) Dept. of Food Science & Technology, Catholic Univ. of Daegu, Hayang, 712-702, South Korea Crawfish shell waste is an abundant and unexploited resource for chitosan extraction. Inherent antimicrobial properties and film-forming ability of chitosan make it an ideal for use as biodegradable antimicrobial packaging material. Traditional chitosan production involves: deproteinization (DP), demineralization (DM), decolorization (DC), and deacetylation (DA). Process modification of chitosan production affects film properties. This study evaluated film-forming ability of various crawfish chitosans. Effects of process modification of chitosan production and film-casting solvents on physicochemical properties of films were evaluated. Four chitosans were prepared from traditional (DPMCA) and modified process [excluding either DP, DC, or both DP & DC]. Degree of deacetylation (DD), molecular weight (Mw), and viscosity of chitosans were determined. Film-forming ability of chitosan solution (1%w/v) in 1% acetic, ascorbic, formic, lactic, and/or malic acid was evaluated. Color, transparency, swelling, adsorption, and tensile mechanical properties of films were evaluated. Triplicate experiments were conducted. Data were statistically analyzed (α=0.05). Chitosans varied in Mw (3,584-10,168 Da), DD (82-83%), and viscosity (8-48 cP). Film-forming ability of chitosan was poor when ascorbic, lactic or malic acid was used as a film-casting solvent; chitosan-ascorbate film was very brittle, chitosan-lactate and chitosan-malate films were highly hydrophilic. All chitosans exhibited excellent film-forming ability with acetic or formic acids, resulting in flexible and transparent films that resemble plastic films. Process modification of chitosan production and film-casting solvents significantly (p<0.05) affected color, transparency, and tensile strength of films. Film-casting solvents did not affect degree of swelling of films. Process modification of chitosan production did not affect adsorption of chitosan-acetate films. The most desirable film was prepared from non-deproteinized chitosan formed with acetic acid; this film possessed tensile strength of 135.8 MPa, elongation of 37.16%, and modulus of 3384.8 Mpa. This study demonstrated feasibility of developing antimicrobial edible films from crawfish chitosans. Some critical factors required for desirable film properties were identified.
Session 89B, Aquatic Food Products: Surimi, gels and by-products
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |