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: Volatile Compounds Profiling and Markers Identification in Various Meat Broths Using SPME-GC-MS
Abstrak: Halal authentication for food products is critical worldwide, especially for muslim. Meat broth is one of the food products frequently adulterated with less expensive or non-halal ingredients. Halal authentication can be done using a DNA or protein-based approach, but this research aims to develop an authentication method that is easy, fast, and sensitive. Empirically, broth prepared from different type of meat has a different aroma. As a result, in this study, a volatilomics approach will be used to profile volatile compounds from various meat broths (chicken, pork, beef, goat, and duck) and to determine the typical marker compounds in each meat broth. The profile of volatile compounds was identified using the solid phase microextraction method combined with gas chromatography-mass spectrometry (SPME-GC-MS). Multivariate analysis was used to determine the differentiating compounds in meat broth: principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA). The volatile compounds identified in this study for chicken, pork, beef, goat, and duck broth (89, 79, 76, 78, and 99 compounds, respectively). The aldehyde group is the most volatile compound in various meat broths because it has a low odor threshold, making it easy to detect and significantly contributing to the distinct flavor of the food matrix. The results of PCA analysis with two principal components can explain 59.5% of the data variation and show a trend of grouping meat broth based on its volatile compounds. Furthermore, the OPLS-DA model analysis revealed that the profile separation of volatile compounds from meat broth was superior to PCA analysis, with a variance value (R2X = 0.79; R2Y = 0.94) and a predictive coefficient value (Q2 = 0.75). Validation of the OPLS-DA model by performing a permutation test and a CV-ANOVA test, which shows that the model is valid and acceptable. The marker compounds were selected based on two criteria: volatile compounds that were positively correlated and had a high VIP (variable importance in projection) value. The main marker compounds contained in pork broth are fatty acids. Fatty acids were detected in the broth because the predominant matrix of the broth was lipid and water. Overall, the marker compounds in pork broth were dodecanoic acid, n-decanoic acid, heptadecanal, 2-pentadecanone, eugenol , 2-tridecanone, and (E,E)-2,4-nonadienal. According to the findings of this study, the volatilomics approach successfully distinguished various meat broths, thus enabling the marker compounds to be used as a database for halal authentication of processed meat products.
Keyword: authentication, broth, discriminant analysis, halal, 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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