89B-22 |
|
S.-O. FERNANDEZ-KIM1, K. Nadarajah1, J. Saidu1, W. Prinyawiwatkul1, H. K. No2, and S. Sathivel3. (1) Dept. of Food Science, Louisiana State Univ. Agricultural Center, 111 Food Science Bldg., Baton Rouge, LA 70803-4200, (2) Dept. of Food Science & Technology, Catholic Univ. of Daegu, Hayang, 712-702, South Korea, (3) Fishery Industrial Technology Center, Univ. of Alaska, Fairbanks, School of Fisheries & Ocean Sciences, 118 Trident Way, Kodiak, AK 99615-7401 Traditional chitosan production (DPMCA) involves 4 sequential steps: deproteinization (DP), demineralization (DM), decolorization (DC), and deacetylation (DA). Process modification of chitosan production affects physicochemical and functional properties of chitosan. This study evaluated effects of altered sequence of demineralization (DM) and decolorization (DC) steps on physicochemical and functional properties of crawfish chitosans. Five crawfish chitosans were prepared in triplicate from traditional (DPMCA) and modified processes (DCMPA, DMCPA, DMPCA, and DMPAC). Two commercial crab chitosans were used as controls. Chitosans were analyzed in triplicate for physicochemical [moisture, nitrogen and ash contents, degree of deacetylation (DD), molecular weight, viscosity, solubility, bulk density, and color whiteness] and functional [water (WBC) and fat (FBC) binding capacity and emulsion capacity (EC) and viscosity (EV)] characteristics. Data were statistically analyzed (α=0.05). Process modification affected properties of crawfish chitosans. Yield, nitrogen and ash contents, and DD of chitosans ranged from 16.7 to 18.8% (based on dry wt. of crawfish shell powder), 6.9 to 8.2%, 0.2 to 1.6%, and 68 to 73%, respectively. DMPAC had the lowest Mw. of 674 dalton with the lowest viscosity. DMPCA and DMPAC, respectively, had the highest (32) and lowest (21) color whiteness value. DMPCA had the highest WBC (745%) vs. lowest (274%) of DMPAC. DMPCA also had the highest FBC (526-578%), regardless of oils used (soybean, canola, corn, sunflower, and olive). Around the isoelectric point (pI) of soy protein, its EC was minimal (96 mL oil emulsified), but about 2.6-fold enhanced (253 mL oil) in the presence of DMPCA chitosan. EC of soy protein increased with increased chitosan concentration. DPMCA, DCMPA, DMCPA, and DMPCA chitosans were comparable in enhancing EC of soy protein, whereas DMPAC chitosan was least effective as an emulsion enhancer due to its lowest Mw. and viscosity. This study demonstrated that altering production protocols affected chitosan functional properties. DMPCA chitosan exhibited superior functional properties compared to other chitosans.
Session 89B, Aquatic Food Products: Surimi, gels and by-products
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |