Characteristics and functional properties of sarcoplasmic proteins from threadfin bream (Nemipterus hexodon)

N Krasaechol, R Sanguandeekul, K Duangmal, R Owusu-Apenten

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


Proteins from surimi processing wastewater make up 20-35% of total proteins from fish muscle. Dehydrated fish sarcoplasmic protein (FSP) from surimi wastewater is currently used as feed. The functionality FSP need to examined to allow its use as a valuable food ingredient. The objectives of this study are to investigate the structure and functionality of FSP from threadfin bream used commercially for surimi manufacture in Thailand. Fish fillet was homogenized with (1:5 w/v) Na-phosphate buffer (0.1M, pH 7.0), centrifuged at 4 o C (12,000g - 15 min) and the product freeze-dried for storage. Dissolved FSP was subjected to several analyses: sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), protease activity assay, apparent lysine and total sulfhydryl content. A standardized foaming test was applied to FSP using sodium caseinate and beta-lactoglobulin for comparison. SDS-PAGE showed that FSP isolate contained 4 size ranges of polypeptides: 8 to 10 kDa (5%), 22 to 26 kDa (12%), 47 to 59 kDa (53%) and 109 to 283 kDa (30%). About 56-67% alkaline protease activity from fish homogenate was retained in FSP isolate. The amino and sulfhydryl contents in FSP were 172 (±1.14) m moles/ g and 32.05 (±0.87) m moles/ g, respectively. FSP was soluble at pH 2 to 4 and pH 7 to 9 with minimum solubility at pH 5.0. The foaming capacity of FSP was 62.5 to 65.2% of the values obtained for beta-lactoglobulin and sodium caseinate and was not pH-sensitive at pH 2-pH 9. Anions (sodium, ammonium, magnesium and calcium: 0.2 M) had no effect on the foaming capacity of FSP but foam stability increased in the presence of magnesium. These trends were similar to those obtained for caseinate or beta-lactoglobulin. These interim results show FSP is a potentially useful protein ingredient. Studies of the gelation and emulsifying characteristics of FSP are in progress.
Original languageEnglish
Title of host publicationUnknown Host Publication
PublisherInstitute of Food Technologists
Number of pages1
Publication statusPublished (in print/issue) - 2005
Event2005 IFT Annual Meeting, July 16 - 20; New Orleans, LA - New Oleans
Duration: 1 Jan 2005 → …


Conference2005 IFT Annual Meeting, July 16 - 20; New Orleans, LA
Period1/01/05 → …


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