Manab, Abdul (2018) Sifat Fisiko Kimia Minuman Kefir Susu Kambing Yang Ditambah Tepung Porang Modifikasi. Doctor thesis, Universitas Brawijaya.
Abstract
Minuman kefir susu kambing merupakan pangan fungsional yang mempunyai manfaat untuk kesehatan. Produk minuman kefir susu kambing selama masa penyimpanan mudah mengalami perubahan sifat fisikokimia akibat dari perubahan sifat protein terutama kasein. Minuman kefir susu kambing membutuhkan bahan tambahan pangan yang mampu menstabilkan kasein agar sifat fisikokimia minuman kefir susu kambing bisa stabil selama masa simpan. Alternatif bahan yang bisa digunakan adalah tepung porang, namun tepung porang banyak mengandung glukomanan yang berupa polisakarida netral yang bisa memicu incompatabilitas antara glukomanan dan kasein. Oleh karena itu, tepung porang memerlukan upaya modifikasi untuk mengurangi incompatabilitas dengan kasein. Disamping itu, tepung porang hasil modifikasi masih membutuhkan optimasi menggunakan metode Response Surface Methodology (RSM) untuk menghasilkan interaksi yang optimum antara tepung porang modifikasi dengan kasein. Titik optimum optimum yang dihasilkan dari metode RSM diterapkan untuk aplikasi tepung porang modifikasi dalam menstabilkan sifat fisikokimia minuman kefir susu kambing selama masa simpan. Tujuan penelitian ini adalah untuk menginvestigasi modifikasi tepung porang menggunakan asam laktat dan microwave, optimasi rasio kasein-tepung porang modifikasi untuk mendapatkan stabilitas emulsi yang optimum pada beberapa tingkat pH dan kadar sukrosa menggunakan aplikasi RSM, membandingkan sifat fisikokimia minuman kefir susu kambing yang dihasilkan menggunakan tepung porang dan tepung porang termodifikasi selama 21 hari masa penyimpanan. Penelitian ini dilaksanakan dalam tiga tahap yaitu Penelitian I metode penelitian deskriptif yang mendeskripsikan dan menginterpretasikan data dilaksanakan dengan menggunakan FTIR, NMR, HPLC-SEC, CLSM, PSA dan Rheology, modifikasi tepung porang menggunakan waterbath pada suhu 90°C selama 30 menit (PAW), radiasi di microwave (Sharp R200J) selama 10 menit (PAM). Penelitian II adalah metode optimasi menggunakan Response Surface Methodology (RSM). Struktur kasein dari UNIPROT (http://uniprot.org), struktur glukomannan (CID:24892726) dan asam laktat (CID:612) diunduh dari Pubchem (pubchem.ncbi. nlm.nih.gov), proses docking menggunakan program autodock vina PyRx 0.8, prediksi interaksi dengan kasein menggunakan Patchdock dan fiberdock. Simulasi dinamika molekul antara glukomanan dan asam laktat menggunakan program AMBER 03 at YASARA 13.4.21, prediksi interaksi antara kompleks glukomanan-asam laktat dengan κ-casein menggunakan Patchdock dan fiberdock, interaksi molekuler untuk mendapatkan sisi aktif yang terlibat dalam interaksi menggunakan program LigandScout 2.0, visualisasi kompleks menggunakan Chimera 1.8. Adapun Penelitian III dilakukan dengan menggunakan metode percobaan tersarang dengan rancangan acak lengkap, dimana data dianalisa dengan anova dan dilanjutkan dengan uji Duncan. Penelitian I ditujukan untuk memodifikasi sifat fisikokimia tepung porang dengan cara pemanasan di waterbath dan microwave dengan penambahan asam laktat. Tepung porang 3 gram dan 100 ml larutan asam laktat Porang flour (3 g) dimasukkan ke dalam Erlenmeyer 250 mL di aduk selama 15 menit pada suhu ruang. Tepung porang diproses di waterbath pada suhu 90°C selama 30 menit (PAW), radiasi di microwave (Sharp R200J) selama 10 menit (PAM). Sedangkan Penelitian II menggunakan perlakuan Rasio Porang xii modifikasi:kasein (0,2, 0,4, dan 0,6), pH 5,5; 5,0; 4,5 dan 4 serta konsentrasi sukrosa 5, 10 dan 15% (b/v), metode optimasi menggunakan Response Surface Methodology (RSM). Dan Penelitian III dilaksanakan untuk membandingkan penambahan tepung porang dan tepung porang termodifikasi terhadap sifat fisiko kimia minuman kefir susu kambing selama masa simpan 21 hari. Hasil pengujian menunjukkan bahwa tepung porang modifikasi (PAW dan PAM) mengalami perubahan puncak gugus fungsional yang berbeda dibandingkan dengan tepung porang alami meliputi gugus OH, CH3, C-C, C=O, C-O-C serta gugus glukosa dan manosa. Spektra HNMR tepung porang modifikasi PAW dan PAM mirip utamanya proton pada CH3 dan CH2, berat molekul lebih tinggi yaitu PAW 2.0 x106 dan PAM 3.0 x106, ukuran partikel PAW dan PAM lebih kecil. Mikrostrukur PAW dan PAM porous dan spongy menunjukkan PAW dan PAM mempunyai accessibilitas air yang tinggi ke bagian amorf. Storage modulus (G‟) dan loss modulus (G”) PAW dan PAM mengalami penurunan dengan meningkatnya suhu. G‟ lebih rendah dibandingkan G”, modulus (G‟ dan G”) tidak mengalami crossing, mengindikasikan bahwa PAW dan PAM mempunyai system visko-elastis yang stabil. Hasil molecular docking menunjukkan bahwa pemanasan glukomanan pada suhu 90°C mengakibatkan ikatan hidrogen diantara molekul glukomanan mengalami kerusakan, terjadi perubahan konformasi glukomanan dan asam laktat, energi pengikatan asam laktat ke glukomanan lebih tinggi. Kompleks glukomanan-asam laktat yang terbentuk oleh pemanasan pada suhu 90°C membentuk kompleks glukomanan-asam laktat dan κ-kasein dengan energi pengikatan yang lebih tinggi. Perubahan konformasi glukomanan dan asam laktat dan sifat larutan glukomanan sangat tergantung pada asam laktat. Kompleks glukomanan-asam laktat lebih mudah terikat ke κ-kasein, didominasi oleh ikatan hidrogen dan interaksi hidrofobik dengan inti hidrofobik κ-kasein. Asam laktat memiliki peran penting dalam peningkatan energi pengikatan, asam laktat penting untuk memediasi interaksi antara glukomanan dan κ-kasein. Kesimpulan Penelitian Tahap I: Tepung porang yang panaskan di waterbath (PAW) dan di microwave (PAM) dengan penambahan asam laktat dapat menghasilkan tepung porang termodifikasi dengan sifat fisikokimia yang mirip dalam bentuk cairan yang kental dengan sifat fisikokimia berupa puncak gugus fungsional, struktur, mikrostruktur, berat molekul serta ukuran partikel yang berbeda dibandingkan dengan tepung porang alami, namun pemanasan menggunakan microwave lebih efektif dibandingkan menggunakan waterbath dalam menghasilkan tepung porang modifikasi. Optimasi stabilitas emulsi menggunakan Response Surface Methodology (RSM) dengan tiga variabel yaitu rasio tepung porang modifikasi:kasein, pH dan kadar sukrosa dikaji untuk mendapatkan stabilitas emulsi sebagai respon. Hasilnya menunjukkan bahwa model respon yang diperoleh adalah quadratic dan stabilitas emulsi yang optimum diperoleh pada rasio tepung porang modifikasi:kasein 1,8, pada pH 5,06 dan kadar sukrosa 4,7%. Stabilitas emulsi yang optimum diprediksi pada nilai 3649,918 menit dengan nilai aktual yang diperoleh adalah 3496,667 menit. Kesimpulan Penelitian Tahap 2 menunjukkan Stabilitas emulsi optimum dicapai pada rasio tepung porang modifikasi:kasein 1,8, pH 5,06 dan kadar sukrosa 4,70%. Stabilitas emulsi optimum diprediksi pada 3649,918 menit, dan nilai aktual pada 3496,667 menit. Kombinasi tepung porang modifikasi dan kasein meningkatkan stabilitas emulsi molekul kasein. Ukuran partikel minuman kefir susu kambing yang ditambah tepung porang termodifikasi menghasilkan ukuran partikel yang lebih kecil daripada perlakuan tepung xiii porang dan sampel kontrol (tanpa penambahan tepung porang). Perlakuan tepung porang termodifikasi menghasilkan mikrostruktur aggregat protein yang lebih homogen. Penambahan tepung porang termodifikasi tidak memberikan perbedaan nyata (P>0,05) diantara pH dan keasaman minuman kefir susu kambing, namun lama penyimpanan yang tersarang pada penambahan bahan penstabil menghasilkan perbedaan yang sangat nyata (P < 0,01) terhadap pH dan keasaman minuman kefir susu kambing. Penambahan tepung porang termodifikasi memberikan perbedaan sangat nyata (P<0,01) diantara emulsi, viskositas, Daya Ikat Air dan Sineresis minuman kefir susu kambing, lama penyimpanan yang tersarang pada penambahan bahan penstabil menghasilkan perbedaan yang sangat nyata (P < 0,01) terhadap emulsi, viskositas Daya Ikat Air dan Sineresis minuman kefir susu kambing. Kesimpulan Penelitian Tahap III: Minuman kefir susu kambing mengalami disrupsi aggregat protein susu oleh tepung porang modifikasi dan sifat fisikokimia minuman kefir susu kambing menjadi lebih stabil selama masa penyimpanan. Kesimpulan dari penelitian ini adalah tepung porang yang diradiasi menggunakan microwave (PAM) dan penambahan asam laktat lebif efektif dalam memodifikasi tepung porang dibandingkan dengan pemanasan di waterbath (PAW). Stabilitas emulsi optimum dicapai pada rasio tepung porang modifikasi:kasein 1,8, pH 5,06 dan kadar sukrosa 4,70%. Stabilitas emulsi optimum diprediksi pada 3649,918 menit, dan nilai aktual pada 3496,667 menit. Kombinasi tepung porang modifikasi dan kasein meningkatkan stabilitas emulsi molekul kasein. Sifat fisikokimia minuman kefir susu kambing selama masa penyimpanan lebih stabil dengan penambahan tepung porang termodifikasi.
English Abstract
The Physicochemical characteristics of goat milk drink prepared using porang flour and modified porang flour and stored for 21 days were studied. Porang flour were modified by lactic acid and conventional heating using waterbath (PAW) and microwave radiation (PAM), and the best modified porang flour and nonmodified porang flour were used in preparation of goat milk kefir drink. This study were carried out in three stages namely: 1st stage was porang flour modification using lactic acid and conventional heating with waterbath (PAW) and microwave radiation (PAM); 2th stage was attempted to identify the optimum emulsion stability from the interaction between casein and modified porang flour (modified porang flour:casein ratio, pH and sucrose content) for maximal stability of the emulsion using Response Surface Methodology (RSM); 3th stage was the comparation of physicochemical characteristic of goat milk kefir drink using modified porang flour and nonmodified porang flour. The purpose of this research were to investigate modify porang flour using lactic acid and conventional heating using waterbath and radiation microwave, to identify the optimum casein-modified porang flour composition for obtaining casein emulsions of improved stability at different pH levels and sucrose contents by the application of Response Surface Methodology (RSM), to compare physicochemical characteristics of goat milk kefir drink produced by using porang flour and modified porang flour throughout 21 days storage period. Modified porang flour by lactic acid and conventional heating using waterbath (PAW) and microwave radiation (PAM) were determined its functional group using FTIR, the chemical structure were studied using H1NMR, molecular weight were measured using HPLC-SEC, and its microstructure were studied using SEM, particles size were measured using PSA and rheology characteristics were determined using Rheometer. The results showed that modified porang either PAW and PAM showed changes on functional group peaks compared to one of native porang flour included OH, CH3, C-C, C=O, C-O-C, manosa and glucosa groups. H1NMR spectra of modified porang flour (PAW and PAM) were similar mainly in proton of CH3 and CH2, molecular weight were higher at PAW 2.0 x106 and PAM 3.0 x106, while particles size of PAW and PAM were smaller. The microstructure of PAW and PAM were porous and spongy indicated that PAW and PAM had higher moisture accessability on the amorph site. Storage modulus (G‟) and loss modulus (G”) of PAW and PAM decreasing with the increased temperature. Lower G‟ compared to G”, and modulus (G‟ and G”) did not showed crossing indicated that PAW and PAM have a stable visco-elasticity. The interaction between glucomannan and lactic acid in water solution at 90°C and 25°C, and interaction κ- casein with glucomannan-lactic acid complex at 90°C and 25°C was investigated using molecular docking calculations. Molecular docking to clearer visual about interaction and molecular changes of glucomannan and lactic acid in water solution at 90°C and 25°C, investigated interaction and molecular changes of glucomannan-lactic acid complex in water solution at 90°C and 25°C. Docking process using autodock vina program at PyRx 0.8. The emulsion stability at different pH levels and sucrose contents by the application of Response Surface Methodology (RSM) and three variables, namely, the modified porang flour : casein ratio, pH and sucrose content were studied in order to ix examine the emulsion stability as a response. The results showed that the response model obtained was quadratic and that the optimum emulsion stability obtained was with a modified porang flour : casein ratio of 1.8 at a pH of 5.06 and sucrose content of 4.7%. The optimum emulsion stability predicted was at a value of 3649,918 minutes with the actual value obtained being 3496,667 minutes. The result of docking to predict interaction between glucomannan-lactic acid complex with casein using Patchdock dan fiberdock. The result of docking analyzed with simulation at 90°C for 1000 ps using force field AMBER 03 at YASARA 13.4.21 program. Visualisation of the complex using Chimera 1.8. The results of molecular docking suggested that heating of glucomannan at 90°C caused hydrogen bonding among glucomannan molecules was broken, conformation changes of glucomannan and lactic acid, higher binding energy of lactic acid to glucomannan. Heating at 90°C formed complex of glucomannan-lactic acid and κ-casein with higher binding energy compared without heating. Conformation changes of glucomannan and lactic acid and the behavior of glucomannan solution was strongly dependent on lactic acid. The complex of glucomannan-lactic acid is more favorable to bind casein, dominated by hydrogen bond and hydrophobic interaction with hydrophobic core of casein. Physicochemical characteristics of goat milk kefir drink produced by using porang flour and modified porang flour were taken at 1, 7, 15 and 21 day of storage period, analysed for microstructure, particle size and ethanol content. Analyses of microstructure using confocal laser scaning microscopy (CLSM), particle size using particle size analyser, ethanol content using gas chromatography (GC).There were significant differences considering the microstructure, particle size and ethanol content of goat milk kefir drink using modified porang flour during storage period. Lower ethanol content was observed in goat milk kefir drink with porang flour and modified porang flour as compared to control sample (no porang flour added) addition. Goat milk kefir drink with modified porang flour addition produced lower particle diameter than control and porang flour treatment, it may due to the disruption of milk protein aggregate by modified porang flour. Confocal microscopy showed at modified porang flour treatment shows more homogenous protein milk aggregate. Modified porang flour addition didnot gave significant effect (P>0,05) on pH and titratable acidity of goat milk kefir drink, but storage period nested on modified porang flour addition gave highly significant effect (P < 0,01) on pH and titratable acidity of goat milk kefir drink. Modified porang flour addition gave highly significant effect (P<0,01) on emulsion, viscosity, water holding capacity and syneresis of goat milk kefir drink, storage period nested on modified porang flour addition gave highly significant effect (P < 0,01) on emulsion, viscosity, water holding capacity and syneresis of goat milk kefir drink. It can be concluded that functional group peaks of modified porang flour (PAW and PAM) changed differently compared to native porang flour, H1- NMR spectra of modified porang flour were similar, with bigger moleculer weight of PAM than PAW, the microstructure were porous and spongy, and rheology characteristics indicated that an unchanged visco-elastic system by thermal treatments. Lactic acid have important role on the behavior of glucomannan in water solution during heating at 90°C and have important role for increasing binding energy to mediate interaction between glucomannan and κ-casein. Lactic acid have important role for increasing binding energy, lactic acid is important to mediate interaction between glucomannan and κ-casein. The response model obtained was quadratic and that the optimum emulsion stability obtained was with a modified porang flour : casein ratio of 1.8 at a pH of 5.06 and sucrose content of 4.7%. x The optimum emulsion stability predicted was at a value of 3649,918 minutes with the actual value obtained being 3496,667 minutes. Modified porang flour produced better physicohemical properties of goat milk kefir drink during 21days refrigeration.
Other obstract
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| Item Type: | Thesis (Doctor) |
|---|---|
| Identification Number: | DIS/641.4/MAN/s/2019/061911458 |
| Uncontrolled Keywords: | Porang flour, Modified porang flour, Lactic acid, Microwave, Waterbath, RSM, Casein, Goat milk kefir drink,-Tepung porang, tepung porang modifikasi, microwave, waterbath, asam laktat, kasein, RSM, minuman kefir susu kambing |
| Subjects: | 600 Technology (Applied sciences) > 641 Food and drink > 641.4 Food preservation and storage |
| Divisions: | S2/S3 > Doktor Ilmu Ternak, Fakultas Peternakan |
| Depositing User: | Endang Susworini |
| Date Deposited: | 16 Feb 2022 03:55 |
| Last Modified: | 16 Feb 2022 03:55 |
| URI: | http://repository.ub.ac.id/id/eprint/189779 |
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