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Title:	Kesan pencampuran protein soya isolat, gelatin dan enzim transglutaminase mikrobial (MTGase) terhadap mutu sosej daging ayam nyahtulang mekanikal
Authors:	Ch'ng Soo Ee (P45116)
Supervisor:	Abdul Salam Babji, Prof. Dr.
Keywords:	Food-Protein content Food Composition
Issue Date:	28-Feb-2015
Description:	Daging Ayam Nyahtulang Mekanikal (DANM) merupakan bahan sampingan yang banyak didapati daripada industri penternakan ayam. Walaupun DANM mempunyai keupayaan mengikat yang rendah dan mudah teroksida, DANM masih popular digunakan untuk memproses makanan tambah nilai daging untuk mengurangkan kos pemprosesan serta mencegah pembaziran. Protein bukan daging seperti protein soya isolat (ISP) dan gelatin ditambahkan untuk meningkatkan sifat fiziko-kimia dan penerimaan keseluruhan sosej DANM. Dalam kajian ini, transglutaminase mikrobial (MTGase) yang dapat mencetuskan ikatan silang -(γ-glutamil)lisina turut ditambahkan untuk mengkaji perubahan ciri-ciri tekstur dalam sosej DANM. Tambahan lagi, ekstrak air daun-daun herba tempatan turut ditambahkan dalam sosej DANM untuk meningkatkan kestabilan oksidatif. Fasa pertama kajian ini dijalankan untuk mengkaji kesan-kesan penambahan dan interaksi antara ISP (2%, 4% dan 6%), gelatin (0%, 0.5% dan 1%) dan MTGase (0%, 0.3% dan 0.6%) ke atas ciri-ciri keupayaan memegang air (WHC), analisis profil tekstur (TPA) (kekerasan, keelastikan, kekohesifan, kekunyahan dan kebergetahan) dan warna [kecerahan (L*), kemerahan (a*) dan kekuningan (b*)] dengan menggunakan Metodologi Permukaan Tindakbalas (RSM). Secara umumnya, peningkatan kandungan ISP dan MTGase menunjukkan kesan signifikan (P<0.05) ke atas semua respon tersebut kecuali kelastikan, kekohesifan dan kekuningan. Gelatin pula hanya menunjukkan kesan signifikan ke atas WHC, kecerahan (L*) dan kemerahan (a*) dan tiada kesan ketara ke atas ciri-ciri tekstur. Walaupun begitu, ketiga-tiga faktor ini adalah tidak berssandar dan interaksi antaranya tidak menunjukkan perbezaan signifikan. Formulasi yang dioptimumkan iaitu F1(2% ISP + 0.32% MTGase + 0.69% Gelatin) dipilih untuk dijalankan kajian seterusnya. Fasa kedua kajian ini dijalankan untuk mengkaji dan mengenalpasti pembentukan ikatan silang yang dicetuskn oleh MTGase dengan sumber-sumber protein (DANM, ISP dan gelatin) dalam sistem sosej DANM. Profil asid amino dikaji dengan Kromatografi Cecair Prestasi Tinggi (HPLC) untuk menentukan kandungan asid glutamik (Glu) dan lisina (Lys). Keputusan diperolehi menunjukan ISP mengandungi kandungan Glu dan Lys (12.91mg/g dan 4.10mg/g) yang paling tinggi (P<0.05) diikuti dengan gelatin pada 7.46 mg/g dan 2.577mg/g dibandingkan dengan DANM yang mencatatkan 3.55mg/g dan 1.897mg/g masingmasing. Keputusan ini mengindikasikan ketiga-tiga sumber protein ini boleh menjadi platform untuk pembentukan ikatan silang susulan penambahan MTGase. Perubahan spektra Spektometer Inframerah Transformasi Fourier (FTIR) dan Spektometer Resonan Magnetik Nuklear (NMR) menunjukkan pembentukan ikatan silang -(γ- glutamil)lisina dalam ketiga-tiga sumber protein tersebut. Fasa ketiga kajian ini dijalankan untuk mengkaji kesan pembentukan ikatan silang dan penambahan ekstrak daun kesum dalam formulasi sosej DANM. Analisis Profil tekstur WHC, warna, pH, Mikroscopi Imbasan Elektron (SEM) dan penilaian sensori (ujian hedonik berskala 7 oleh 50 orang panel tidak terlatih) dijalankan. Ekstrak daun kesum (Polygonum minus) dipilih untuk ditambahkan dalam sosej DANM untuk mengkaji kestabilan oksidatif DANM sosej selepas ujian penyaringan dijalankan. Ekstrak daun kesum menunjukkan jumlah kandungan sebatian fenolik dan aktiviti antipengoksidaan yang paling tinggi (P<0.05) dalam Ujian Aktiviti Pemerangkapan Radikal Bebas DPPH dan Ujian Kuasa Penurunan Ferik (FRAP) dibandingkan dengan ekstrak daun kari (Murraya koenigii Sprang) dan ekstrak daun limau purut (Citrus hystrix D. C.). Kesan kombinasi pembentukan ikatan silang antara MTGase dengan sumber protein dan penambahan sebatian fenolik dari ekstrak daun kesum ke atas kestabilan oksidatif juga dikaji dengan nilai peroksida (POV) dan nilai asid tiobarbiturik (TBARS). Empat formulasi disediakan di mana [T1 (kawalan, 4% ISP); T2 (2% ISP + 0.69% gelatin + 0.32% MTGase); T3 (2% ISP + 0.69% gelatin + 0.32% MTGase + 200ppm Kesum extracts) dan T4 (2% ISP + 0.69% gelatin + 0.32% MTGase + 200ppm BHA:BHT (1:1)]. Secara umumnya, formulasi yang ditambahkan dengan MTGase (T2, T3 and T4) mencatatkan nilai kekerasan yang lebih tinggi (P<0.05) serta merupakan emulsi yang lebih padat dan serata ditunjukkan dalam analisis mikrostruktur dibandingkan dengan kawalan T1. Ujian sensori juga menunjukkan T2, T3 dan T4 mempunyai skor yang lebih tinggi (P<0.05) dalam atribut aroma, rasa, tekstur, kejusian dan penerimaan keseluruhan tetapi tiada perbezaan signifikan pada warna dibandingkan dengan kawalan. Walaupun begitu, tiada perbezaan signifikan antara T2, T3 dan T4 menunjukkan penambahan ekstrak daun kesum pada 200ppm tidak mampu mempengaruhi tektur dan atribut sensori dalam sosej DANM. Ujian jangka hayat dijalankan di mana sosej DANM disimpan sejuk pada 4±1°C selama 14 hari untuk memperhatikan perubahan kualiti dan kestabilan oksidatifnya. Pembentukan ikatan silang -(γ-glutamil)lisina oleh MTGase dapat menurunkan nilai peroksida (POV) (P<0.05) dan nilai asid tiobarbiturik (TBARS) (P<0.05) sepanjang tempoh penyimpanan. Penambahan ekstrak daun kesum pada 200ppm dapat menurunkan lagi nilai POV dan TBARS secara signifikan. Secara kesimpulannya, penambahan MTGase dapat meningkatkan kualiti sosej DANM secara ketara dalam ciri-ciri seperti WHC, TPA, SEM, sensori dan kestabilan oksidatif tetapi tiada kesan signifikan atas warna dan pH. Penambahan sebatian fenolik yang diekstrak dari sumber semulajadi seperti daun kesum pula tidak akan mempengaruhi ciri-ciri fiziko kimia tetapi meningkatkan kestabilan oksifdatif dalam tempoh penyimpanan.,Ph.D,Mechanically Deboned Chicken Meat (MDCM) is abundantly available as a byproduct from poultry industry. Although MDCM is low in binding ability and is highly susceptible to oxidative deterioration, it is widely used in the value-added meat product industry to reduce the manufacturing cost and prevent wastage. Non-meat proteins such as Isolated Soy Protein (ISP) and gelatin were added to improve the physico-chemical properties and overall acceptability of MDCM sausages. In this study, microbial transglutaminase (MTGase) which can induce the -(γ- glutamyl)lysine cross-links was objectively added to observe the textural characteristics changes in MDCM sausages. Furthermore, aqueous extracts from local herbs was added into MDCM sausage to improve on its oxidative stability. The first phase of this research was carried out to observe the main effects and interaction of ISP (2%, 4% and 6%), gelatin (0%, 0.5% and 1%) and MTGase (0%, 0.3%, 0.6%) on water holding capacity (WHC), textural (hardness, elasticity, cohesiveness, chewiness and gumminess) and colour [lightness (L*), redness (a*) and yellowness (b*)] characteristics by using Response Surface Methodology (RSM). Generally, an increase addition of ISP and MTGase exhibited significant effects (P<0.05) on all responses stated above except elasticity, cohesiveness and yellowness (P>0.05). Gelatin only exhibited significant effects on WHC, lightness (L*) and redness (a*) but not on textural characteristics. However all the 3 factors were independent and interaction of these factors showed no significant differences (P>0.05). Optimized formulation whereby F1(2% ISP + 0.32% MTGase + 0.69% Gelatin) was selected for further research. The second phase of this study was performed to investigate and identify the formation of crosslinking by MTGase with the protein sources (MDCM, ISP and gelatin) in MDCM sausages. Amino acid profiles were evaluated by High Performance Liquid Chromatography (HPLC) to determine glutamic acid (Glu) and lysine (Lys) content. Results showed that ISP contained significantly highest Glu and Lys (12.91mg/g and 4.10mg/g) followed by gelatin at 7.46 mg/g and 2.57mg/g as compared to MDCM with 3.55mg/g and 1.897mg/g respectively. The results indicated all three protein sources displayed a potential platform for MTGase mediated crosslinkage. Changes in Fourier Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR) spectra evidently indicated the formation of - (γ-glutamyl)lysine cross-links in all these ingredients. In the third phase of this study, the effects of MTGase-mediated cross linkage with optimized formulation (2% ISP + 0.32% MTGase + 0.69% Gelatin) was studied by Texture Profile Analyses (TPA), WHC, colour, pH, Scanning electron Microscopy (SEM) and sensory evaluation (7- scale hedonic score by 50 untrained panellists). Aqueous Kesum leaves (Polygonum minus) extracts was selected to be added in the MDCM sausage formulation for oxidative stability study as it showed highest total phenolic content (P<0.05) and antioxidant activity through DPPH scavenging activity test and ferric reducing power assay compared to curry leaves (Murraya koenigii Sprang) and kaffir lime leaves (Citrus hystrix D. C.) extracts. The combined effects of MTGase mediated crosslinkage with protein sources and addition of phenolic compounds extracted from Kesum leaves on oxidative stability were examined by peroxide value (POV) and Thiobarbituric acid (TBARS) value. Four formulations of MDCM sausages were prepared [T1 (control, 4% ISP); T2 (2% ISP + 0.69% gelatine + 0.32% MTGase); T3 (2% ISP + 0.69% gelatine + 0.32% MTGase + 200ppm Kesum extracts) and T4 (2% ISP + 0.69% gelatine + 0.32% MTGase + 200ppm BHA:BHT (1:1)]. Generally, formulation with MTGase (T2, T3 and T4) exhibited significant higher (P<0.05) score in hardness as compared to T1 producing a more uniform and compact emulsion reflected in microstructure analyses. Sensory evaluation also showed that T2, T3 and T4 had significantly higher score in the attribute of aroma, taste, texture, juiciness and overall acceptance but not on colour as compared to T1. However, no significant differences was observed among T2, T3 and T4 indicating phenolic compound added at 200ppm is not capable in affecting the texture and sensory attributes of MDCM sausages. Shelf life study was carried out whereby the MDCM sausages were kept chilled at (4±1°C) for 14 days to observe its quality changes and oxidative stability. The formation of -(γ-glutamyl)lysine crosslink by MTGase successfully reduce peroxide value (POV) (P<0.05) and Thiobarbituric acid (TBARS) value (P<0.05) throughout the storage period. The addition of 200ppm kesum extracts further reduce POV and TBARS value (P<0.05). In conclusion, incorporation of MTGase showed significant effects in improving overall quality of MDCM sausage such as WHC, TPA, SEM, sensory characteristics and oxidative stability but not on colour and pH. The addidtion of phenolic compound from natural derived sources such as kesum extracts did not effect its physico-chemical properties but further improve on its oxidative stability during storage.
Pages:	248
Call Number:	TX545.C494 2015
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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