Judul: Volatilomic of Fish and Pork Gelatin Using HS SPME GC-MS for Halal Authentication
Abstrak: Gelatin merupakan komoditi pangan berasal dari bahan hewani yang sangat sulit ditelusuri kehalalannya karena asal muasal hewan tidak nampak secara fisik. Pembuatan gelatin juga melewati beberapa proses yang menimbulkan komponen pada gelatin tidak dapat dianalisis untuk mengetahui sumber asalnya. Autentikasi halal menjadi salah satu cara menghilangkan kekhawatiran masyarakat dalam status kehalalan gelatin yang beredar. Berbagai metode telah dikembangkan dalam eksplorasi pembeda komponen halal dan non-halal namun masih memiliki kelemahan diantaranya kesulitan mendeteksi protein yang terdenaturasi, proses analisis degan waktu yang cukup lama, membutuhkan instrumen yang sangat canggih, biaya yang tak terjangkau dan spesifitas yang rendah. Setiap gelatin memiliki aroma khas yang disebabkan oleh perbedaan komponen asam amino penyusun gelatin yang identik dengan bahan bakunya sehingga senyawa volatil berpotensi menjadi senyawa penanda pada gelatin. Penelitian ini bertujuan membandingkan profil senyawa volatil gelatin yang terbuat dari berbagai ikan dan gelatin babi menggunakan metode ekstraksi mikro fase padat-kromatografi gas-spektrometri massa (SPME/GC-MS) dan analisis data multivariat. Hasil penelitian menunjukkan bahwa metode kombinasi SPME dan GC-MS terbukti dapat mengklasifikasikan gelatin sesuai dengan profil senyawa volatilnya. Senyawa penanda yang paling berpengaruh pada kelompok gelatin ikan adalah hexadecane, sedangkan pada kelompok gelatin babi adalah decane. Keduanya berasal dari golongan hidrokarbon dan belum pernah dilaporkan pada penelitian sebelumnya terkait analisis gelatin. Namun, hexadecane pernah dilaporkan sebagai senyawa volatil dengan konsentrasi tertinggi pada daging babi, sedangkan decane dilaporkan sebagai senyawa volatil yang ada pada daging ikan., Gelatin is a food additive derived mainly from animal which halal status difficult to trace because the origin of animal is not visible. Gelatin also through several processes that make components can’t be analyzed to determine gelatin’s source. Various methods have been developed in the exploration of gelatins differentiation from various sources. There are several limitations, including difficulty in detecting denaturated proteins, long time analysis process, expensive, sophisticated instruments, and low specificity. Each gelatin has a typical aroma due to differences in the amino acid components which are identical to the raw material, so that volatile compounds have the potential to be marker compounds in gelatin. This study aims to compare the profile of volatile compounds of gelatin made from various fish and pork gelatin using solid phase micro-extraction method-gas chromatography-mass spectrometry (SPME/GC-MS) and multivariate data analysis. The results showed that the SPME and GC-MS combination method was proven to be able to classify gelatin according to the profile of its volatile compounds. The most influential marker compound in the fish gelatin group was hexadecane, while in the pork gelatin group it was decane. Both are derived from the hydrocarbon group and have not been reported in previous studies related to gelatin analysis. However, hexadecane has been reported as a volatile compound with the highest concentration in pork, while decane has been reported as a volatile compound in fish meat.
Keyword: Authentication, GC-MS, gelatin, SPME, volatile

Judul: Differentiation of Porcine and Bovine Gelatin and Their Admixture Using SPME-GCMS Method and Multivariate Analysis
Abstrak: Gelatin merupakan produk hidrolisis parsial dari kolagen. Bahan baku gelatin sebagian besar berasal dari kulit babi, kulit sapi, tulang babi, dan tulang sapi. Gelatin dibedakan dengan memanfaatkan salah satu sifat gelatin, yaitu aroma khas berupa komponen volatil yang berasal dari bahan bakunya. Sampel dianalisis menggunakan metode solid phase microextraction (SPME) dan gas chromatography–mass spectrometry (GC-MS) serta analisis multivariat. Hasil analisis multivariat principle component analysis (PCA) dan partial least square-discriminant analysis (PLS-DA) menunjukkan bahwa sampel gelatin babi dan gelatin sapi dapat terklasifikasi dengan baik. Namun, sampel gelatin campuran tidak dapat terklasifikasi dengan baik. Hasil analisis senyawa volatil penanda yang berpengaruh pada pengklasifikasian kelas gelatin babi ialah 3-tetradekun-1-ol, 1,1,2-trimetilsikloundekana, (E)-2-dodeken-1-al, 8-hidroksi-2,2-dimetil-dek-5-en-3-on, dan (E)-2-undeken-1-ol. Senyawa volatil penanda yang berpengaruh pada pengklasifikasian kelas gelatin sapi ialah 1-pentakosena, 3,7-dimetildekana, N-(1-feniletil)formamida, 5-metiltetradekana, dan heksil sianoasetat., Gelatin is a product of partial hydrolysis of collagen. Most of the raw materials for gelatin come from pork skins, cow skins, pork bones, and cow bones. Gelatin can be differentiated by using one of the gelatin's characteristics: distinctive aroma originated by volatile components of the raw material. The samples were analyzed using solid-phase microextraction (SPME), gas chromatography-mass spectrometry (GC-MS), and multivariate analysis. The results of the principal component analysis (PCA) dan partial least square-discriminant analysis (PLS-DA) showed that the samples of porcine gelatin and bovine gelatin could be classified well. However, the mixed gelatin samples could not be classified properly. The volatile marker compounds that affected the classification of porcine gelatin classes are 3-tetradecyn-1-ol, 1,1,2-trimethylcycloundecane, (E)-2-dodecen-1-al, 8-hydroxy-2,2-dimethyl-dec-5-en-3-one, and (E)-2-udecen-1-ol. The volatile marker compounds that affected the classification of bovine gelatin classes are 3,7-dimethyldecane, N-(1-phenylethyl)formamide, 5-methyltetradecane, and hexyl cyanoacetate.
Keyword: gelatin, GC-MS, SPME, volatilomics

Judul: Bifurkasi Hopf pada Model Siklus Bisnis Kaldor Kalecki tanpa dan dengan Waktu Tunda
Abstrak: Business cycle model is one of dynamical system models in economic. One of the business cycles model is Kaldor-Kalecki model. Kaldor-Kalecki business cycle model that is written in delayed defferential equations, is a business cycle model that involves gross product and capital stock of a company. In this paper Kaldor-Kalecki business cycle model is analyzed using both nondelay and delay in time of capital stock. By Taylor expansion for the time delayed model, an analysis of stability around the fixed points has been done. Furthermore, by using Hopf bifurcation theorem, it can be shown that there exists periodic orbits and limit cycle. In the nondelayed model, changing the parameter of goods market could lead to the occurrence of Hopf bifurcation and the existence of limit cycle. Similarly, for the delayed model, it has been shown that changing the time delay parameter may result in the occurrence of Hopf bifurcation and limit cycle.
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