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Surimi wash water treatment by chitosan-alginate complexes : effect of molecular weight and degree of deacetylation of chitosan and nutritional evaluation of solids recovered by the treatment

Soluble surimi wash water (SWW) proteins could be recovered using
chitosan (Chi) complexed with alginate (Chi-Alg) generating co-products for feed
formulations. Chi with a degree of deacetylation (DD) of 84% complexed with Alg
at a mixing ratio (MR) of 0.2 was used to study Chi-Alg concentration and
treatment time protein recovery effects. Insoluble SWW solids were removed by
centrifugation and the supernatant was then adjusted to pH 6. Flocculation at 20��C
using Chi-Alg at 20, 40, 100 and 150 mg/L SWW was aided by 5 mm agitation and
holding for 30 mm, 1h and 24h. Concentration had an effect between low (20 and
40 mg/L) and high (100 and 150 mg/L) levels. Time had an effect between 30 min
and 1h but not between 1 and 24 h. Turbidity reduction was affected only by
concentration. 100 mg Chi-Alg/L SWW for 1 h achieved 83% protein adsorption
and 97% turbidity reduction while lower concentrations yielding higher adsorption
required longer times. Fourier Transform Infrared (FTIR) analysis of untreated and
Chi-Alg treated SWW solids confirmed protein adsorption. Amide band areas
normalized against a common 3005-2880 cm����� region confirmed the high protein
recovery by 100 mg Chi-Alg/L SWW. Six Chi samples differing in molecular
weight (MW) and degree of deacetylation (DD) were tested to recover soluble
SWW solids using 20, 40, and 100 mg Chi-Alg/L SWW (0.2 MR, 1h). High (94%,
93%) and low (75%) DD chitosan had lower protein adsorption (73-75%) when
compared to the intermediate (84%) DD chitosan (74-83%). Intermediate DD and
high MW Chi seemed to perform better; however, SY-1000 with 94% DD did not
follow this trend (79-86% protein adsorption, 85-92% turbidity reduction).
Insoluble SWW (P1) and soluble solids (P2) recovered using 150 mg Chi-
Alg/L SWW contained 61.4 and 73.1% protein, respectively. Rat diets formulated
with 10% protein substitution by P1 and 10% and 15% by P2 had acceptability and
protein efficiency ratios (PER) as high as the casein control with no deleterious
effects. Rat diets with 100% P2 protein substitution showed higher PER and net
protein ratio than the casein control with no deleterious effects. Protein recovered
from SWW using Chi-Alg has the potential to be used in commercial feed
formulations. / Graduation date: 2004

Identiferoai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/30819
Date11 November 2003
CreatorsWibowo, Singgih
ContributorsTorres, J. Antonio
Source SetsOregon State University
Languageen_US
Detected LanguageEnglish
TypeThesis/Dissertation

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