Tahir Ahmad

Dr. Tahir Ahmad

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Research Focus & Metrics

Academic Career Length

23Years (2004-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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7 May 2021 in Scientific Reports
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NHNurfarhana Hassan
Nurfarhana Hassan
TATahir Ahmad
Tahir Ahmad
NZNorhidayu M. Zain
Norhidayu M. Zain
SASiti Rahmah Awang
Siti Rahmah Awang
Gelatin is a protein substance that is widely used in food and pharmaceutical industries. Gelatin is mainly derived from bovine and porcine sources. Fish gelatin is becoming alternative source of gelatin due to concern on health issue and religious constraints. Numerous studies for identification of gelatin sources have been reported. In this study, Fourier transform infrared (FTIR) spectroscopy was used in combination with chemometrics fuzzy autocatalytic set (c-FACS) to distinguish between bovine, porcine and fish gelatins. The gelatin spectra at Amide and 1600–1000 cm−1 regions were analyzed using c-FACS and the results were compared to principal component analysis (PCA) and linear discriminant analysis (LDA). The results obtained from c-FACS method showed that each bovine, porcine and fish gelatin possessed dominant wavenumbers at 1470–1475 cm−1, 1444–1450 cm−1 and 1496–1500 cm−1 respectively, which represent their unique signatures. Furthermore, a clear distinction for porcine gelatin was observed in coordinated FACS. The c-FACS method is rigor and faster than PCA and LDA in differentiating the gelatin sources. The novel method promises at least another chemometrics method for FTIR related analysis and the possibilities for other applications are endless.

15 November 2018 in Journal of Food Science
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NHNurfarhana Hassan
Nurfarhana Hassan
TATahir Ahmad
Tahir Ahmad
NZNorhidayu Muhamad Zain
Norhidayu Muhamad Zain
The issue of food authenticity has become a concern among religious adherents, particularly Muslims, due to the possible presence of nonhalal ingredients in foods as well as other commercial products. One of the nonhalal ingredients that commonly found in food and pharmaceutical products is gelatin which extracted from porcine source. Bovine and fish gelatin are also becoming the main commercial sources of gelatin. However, unclear information and labeling regarding the actual sources of gelatin in food and pharmaceutical products have become the main concern in halal authenticity issue since porcine consumption is prohibited for Muslims. Hence, numerous analytical methods involving chemical and chemometric analysis have been developed to identify the sources of gelatin. Chemical analysis techniques such as biochemical, chromatography, electrophoretic, and spectroscopic are usually combined with chemometric and mathematical methods such as principal component analysis, cluster, discriminant, and Fourier transform analysis for the gelatin classification. A sample result from Fourier transform infrared spectroscopy analysis, which combines Fourier transform and spectroscopic technique, is included in this paper. This paper presents an overview of chemical and chemometric methods involved in identification of different types of gelatin, which is important for halal authentication purposes.

10 November 2012 in Journal of Optimization Theory and Applications
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IKIzaz Khan
Izaz Khan
TATahir Ahmad
Tahir Ahmad
NMNormah Maan
Normah Maan

16 December 2009 in Journal of Mathematical Chemistry
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TATahir Ahmad
Tahir Ahmad
SBSabariah Baharun
Sabariah Baharun
KAKhairil Anuar Arshad
Khairil Anuar Arshad

13 March 2021 in Processes
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AAAzmirul Ashaari
Azmirul Ashaari
TATahir Ahmad
Tahir Ahmad
Siti Rahmah AwangSiti Rahmah Awang
Siti Rahmah Awang
NSNoorsufia Abd Shukor
Noorsufia Abd Shukor
Graph theory is a well-established mathematical concept that is widely used in numerous applications such as in biology, chemistry and network analysis. The advancement in the theory of graph has led to the development of a concept called autocatalytic set. In this paper, a mathematical modeling technique namely graph-based dynamic modeling of palm oil refining process is introduced. The system parameters are identified in detail in the beginning of the paper. The parameters involved are the chemical compounds used or produced during the refining process. These identified parameters are then modeled as the vertices and edges of the graph. The dynamicity of the system is then simulated and analyzed. The system is simulated using MATLAB software programing. The two final products produced by the refining process agreed with results obtained from other published methods. Hence, the effectiveness and simplicity of the model are established.

6 November 2020 in Mathematics
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NHNurfarhana Hassan
Nurfarhana Hassan
TATahir Ahmad
Tahir Ahmad
NZNorhidayu M. Zain
Norhidayu M. Zain
Siti Rahmah AwangSiti Rahmah Awang
Siti Rahmah Awang
Graph theory is a well-established concept that is widely used in numerous applications such as in biology, chemistry and network analysis. The advancement in the theory of graph has led to the development of a new concept called fuzzy autocatalytic set. In this paper, a fuzzy graph-based chemometrics method, namely, chemometrics fuzzy autocatalytic set (c-FACS) is developed and applied for gelatin authentication. The issue on authenticity of gelatin has become a sensitive issue among some religious communities. Due to the matter, Fourier transform infrared (FTIR) spectra of bovine, porcine and fish gelatins are analyzed using c-FACS to identify their signatures and differences and presented in this paper. The results from the c-FACS analysis showed distinct features of each gelatin, particularly porcine. Furthermore, the new method is faster than principal component analysis (PCA) in identifying the gelatin sources.