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Title:	Optimization of gelatin extraction and functional properties of gelatin products from catfish (pangasius sutchi) skin and bone
Authors:	Fatemeh Mahmoodani (P51660)
Supervisor:	Abdul Salam Babji, Prof. Dr.
Keywords:	Universiti Kebangsaan Malaysia -- Dissertations Dissertations, Academic -- Malaysia Gelatin -- Physiology Catfishes
Issue Date:	1-Sep-2012
Description:	The present study was carried out to determine the physicochemical and functional properties of gelatin extracted from catfish Pangasius sutchi skin and bone. To optimize the gelatin extraction Response Surface Methodology (RSM) with a 4-factor, 5-level Central Composite Design was used. The factors were namely NaOH and acetic acid concentration, and extraction time and temperature for skin, and HCl concentration, treatment time, and extraction time and temperature for bone. The optimum extraction conditions were found to be 0.2 M NaOH concentration, 0.1 M acetic acid concentration, 63.70 °C extraction temperature and 2.41 h extraction time for skin, and 2.74 % HCl concentration, 20.15 h pre-treatment time, 74.73 °C extraction temperature and 5.26 h extraction time for bone. After optimization, the hydroxyproline recovery, as independent variable, was 68.16 and 67.64 %, respectively for skin and bone gelatin. The gelatin yield, viscosity and gelling properties of P. sutchi skin gelatin were significantly higher than bone gelatin. The optimized gelatin yield was, 23.61 and 13.86 %, respectively for skin and bone. In this investigation, P. sutchi skin gelatin exhibited significantly higher gel strength (398 g), viscosity (4.17 mPa s), gelling (32.5 °C) and melting (24.5°C) point than corresponding bone (255 g, 3.1 mPa s, 27.5 and 20°C, respectively) and bovine (325 g, 3.41 mPa s, 29.9 and 23.5°C, respectively) gelatins. In addition, the colour of extracted gelatins was more bright compared to bovine gelatin, which could be a positive attribute in food application. In the present study, sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that bone gelatin had considerable amount of low molecular weight components, indicating more degree of collagen degradation, which did not appear in the skin gelatin. With regard to functional properties, functional bioactive peptides with in vitro angiotensin converting enzyme inhibitory activity have been isolated from P. sutchi skin and bone gelatin hydrolysates. Based on the results of the present study, alcalase gelatin hydrolysates of skin and bone indicated high degree of hydrolysis, 64.87 and 70.31 %, respectively. The hydrolysates were ultra-filtered into two fractions: 10 kDa and 3 kDa fractions. Both hydrolysates and fractionates were tested for ACE inhibition and peptidic fractions of skin (IC50 = 0.06 mg/ml) and bone (IC50 = 0.03 mg/ml) gelatins with molecular weight less than 3 kDa contained the highest inhibition activity. In addition, ultra-filtrated fractions with the highest ACE inhibition activity were tested for amino acid composition and digestion stability. The results may indicate that alcalase cleaved hydrophobic amino acid peptide bonds of gelatin hydrolysates to favor the interaction between peptides and ACE and therefore, decrease or inhibit the activity of enzyme. The results also suggested that fractions with the highest ACE inhibition activity were resistant to gastrointestinal digestion enzymes, which means they could possibly maintain their inhibition activity after being orally administered. In general, the results of the present study suggested that the extracted gelatin from P. sutchi processing by-products could be utilized as ingredients in food and pharmaceutical industries.,Certification of Master's / Doctoral Thesis" is not available
Pages:	148
Call Number:	QP552.G4M337 2012 tesis
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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