Sains Ma1aysiana 34(2): 7-15 (2005)

Optimization of Headspace Temperature and Time Sampling for Identification of Palm Sugar Volatile Components Using

Response Surface Methodology

(Pengoptimuman Persampelan Ruang Tutupan Sebatian Meruap

Gula Kabung menggunakan Kaedah Permukaan Respons)

Ho Chun Wai, Wan Aida Wan Mustapha,

Mohd. Yusof Maskat & Osman Hassan

School of Chemical Sciences and Food Technology

Faculty of Science and Technology

Universiti Kebangsaan Malaysia

43600 UKM Bangi, Selangor D.E., Malaysia

ABSTRACT

The aim of this work was to optimize equilibration temperature and time for analyzing volatiles components in palm sugar (Arenga pinnata) by headspace solid phase micro-extraction (HS-SPME) method. A 50/30 lm DVB/CAR/PDMS fiber was used to adsorb the volatile components from the headspace region. A central composite statistical design was used to evaluate the effects of different temperatures (40 to 60°C) and sampling time (5 to 25 min) on the total yield of palm sugar volatile components. Response surfaces were plotted, and these together with results from some additional experiments (axial and center points) produced optimal extraction conditions for HS-SPME at 55°C and 12 min. These conditions were similar to N-heterocyclic compounds where the relative percentage area (RPA) was > 88.0% of total volatiles.

Keywords: Palm sugar; headspace solid phase microextraction (HS-SPME); N-heterocyclic compounds; response surface methodology

ABSTRAK

Kajian ini dijalankan untuk mengoptimum suhu dan masa persampelan bagi analisis sebatian meruap gula kabung (Arenga pinnata) dengan kaedah ruang tutupan pengekstrakan mikro fasa pepejal (RT-PMFP). Fiber 50/30 lm DVB/CAR/PDMS digunakan untuk mengekstrak sebatian meruap daripada ruang tutupan. Rekabentuk statistik komposit tengah digunakan untuk menilai kesan pelbagai tahap suhu (40 hingga 60°C) dan masa persampelan (5 hingga 25 min) terhadap jumlah hasil ekstrakan sebatian meruap gula kabung. Permukaan respons diplotkan dan bersama dengan keputusan hasil daripada beberapa ekperimen tambahan (titik aksial dan tengah) mendapati bahawa keadaan pengekstrakan optimum untuk jumlah sebatian meruap gula kabung adalah pada suhu 55°C selama 12 min. Keputusan yang sarna diperolehi dengan komponen N-heterosiklik di mana relatif kawasan puncak merangkumi lebih daripada 88.0% jumlah sebatian meruap.

Kata kunci: Gula kabung; ruang tutupan pengekstrakan mikro fasa pepejal (RT-PMFP); N-heterosiklik sebatian; metodologi respons permukaan

RUJUKAN/REFERENCES

Alexandrou, N., Lawrence, M. & Pawliszyn, J. 1992. Cleanup of complex organic mixtures using supercritical fluids and selective absorbents. Anal. Chem. 64:301-311.

Ames, J. M., Guy, R. C. E. & Kipping, G. J. 2001. Effect of pH, Temperature, and Moisture on the Formation of Volatile Compouds in Glycine/Glucose Model Systems. J. Agric. Food Chem. 49:4315-4323.

Barcarolo, R., Tutta, C. & Casson, P. 1996. Aroma Compounds. Dlm. Nollet, L (pnyt). Handbook of Food Analysis, hlm. New York: Marcel Dekker, Inc.

Bene, A., Luisier, J. L., Pichler, P. & Villettaz, J. C. 1999. A new apparatus for the detection of volatiles, the TV9000. Dlm: Proceedings of the 6^th International Symposium, Olfactiontp and Electronic Nose, hlm. 80-83. Germany: Institute of Physical Chemistry, University of Tubingen.

Buttery, R. G., Orts, W. J., Takeoka, G. R. & Nam, Y. 1999. Volatile Flavor Components of Rice Cakes. J. Agric. Food Chem. 47: 4353-4356.

Chen, J. H. & Ho, C. T. 1999. Comparison of Volatile Generation in Serine/Threonine/Glu tamine- Ri bose/GI ucose/Fructose Model Systems. J. Agric. Food Chem. 47:643-647.

Chin, H. W, Bernhard, R. A. & Rosenberg, M. 1996. Solid-phase mlcroextraction for cheese volatile compounds analysis. J. Food Sci. 61:1118-1122.

Cristina, S., Diana, A., Jose, B. & Concepcion, C. 2001. Optimizing Headspace Temperature and Time Sampling for Identification of Volatile Compounds in Ground Roasted Arabica Coffee. J. Agric. Food Chem. 49:1364-1369.

Elmore, J. S., Mottram, D. S., Enser, M. & Wood, J. D. 1999. Effect ofthe Polyunsaturated Fatty Acid Composition of Beef Muscle on the Profile of Aroma Volatiles. J. Agric. Food Chem. 47:1619-1625.

Kataoka, H., Lord, H. L. & Pawliszyn, J. 2000. Application of solid-phase microextraction in food analysis. Journal of Chromatography A. 880: 35-62.

Lopez, M. G. & Norma, A. M. M. 2002. Generation of Maillard Compounds from Inulin during the Thermal Processing of Agave tequilana Weber Var. azul. J. Agric. Food Chem. 50:806-812.

Maga, 1. A. 1992. Pyrazines update. Food Rev. Int. 8: 479-558.

Mejias, R. C., Marin, R. N., de Valme Garcia Moreno, M. & Barroso, C. G. 2002. Optimization of headspace solid phase microextraction for analysis of aromatic compounds in vinegar. Journal of Chromatography A. 953: 7-15.

Pawliszyn, J. 1997. Solid-Phase Microextraction. Theory and Practice. New York: Wiley-VCH Inc.

Pawliszyn, J. 2000. Theory of solid-phase microextraction. Journal of Chromatographic Science. 38: 270-278.

Pollien, P., Ott, A., Montigon, F., Baumgartner, M., Munoz-Box, R. & Chaintreau, A. 1997. Hypenated Headspace-Gas Chromatography-Sniffing Technique: Screening of Impact Odorants and Quantitative Aromagram Comparions. J. Agric. Food Chern. 45: 2630-2637.

Robbat, A., Liu, T. & Abraham, B. 1992. On-site detection of polycyclic aromatic hydrocarbons in contaminated soils by thermal desorption gas chromatography/mass spectrometry. Anal. Chern. 64: 1477-1483.

Roberts, D. D. & Pollien, P. 2000. Solid-Phase Micro-extraction Method Development for Headspace Analysis of Volatile Flavour Compounds. J. Agric. Food Chem. 48:2430-2437.

Ruiz, J., Cava, R., Ventanas, J. & Jensen, M. T. 1998. Headspace Solid Phase Microextraction for the analysis of Volatiles in a Meat Product: Dry-Cured Iberian Ham. J. Agric. Food Chem. 46: 4688-4694.

Ruiz, J., Cava, R., Ventanas, J. & Jensen, M. T. 1998. Headspace Solid Phase Microextraction for the analysis of Volatiles in a Meat Product: Dry-Cured Iberian Ham. J. Agric. Food Chem. 46: 4688-4694.

Steffen, A. & Pawliszyn, J. 1996. Analysis of flavour volatile using headspace solid-phase microextraction. J. Agric. Food Chem. 44:2187-2193.

Tae, H. K., Sang, M. L., Young, S. K., Kyoung, H. K., Sangsuk, O. & Hyong, J. L. 2003. Aroma dilution method using GC injector split ratio for volatile compounds extracted by headspace SPME. Food Chem. 83: 151-158.

Vernin, G. & Parkanyi, C. 1982. Mechanisms of formation of heterocyclic compounds in Maillard and pyrolysis reactions. Dlm. Vernin, G. (pnyt.) Chemistry of Heterocyclic Compounds in Flavors and Aromas, hlm. 151-207. New York: Haslted Press.

Yang, X. P. & Peppard, T. 1994. Solid-phase microextraction for flavour analysis. J. Agric. Food Chem. 42: 1925-1930.

Yang, X. P. & Peppard, T. 1995. Solid-phase micro-extraction of flavour compounds - a comparison of two fiber coatings and a discussion of the rules of thumb for adsorption. LC/GC. 13: 83.

Zhang, Z. & Pawliszyn, J. 1993. Solid phase microextraction, a solvent free alternative for sample preparation. Anal. Chem. 65: 1843-1847.

Zhang, Z. & Pawliszyn, J. 1995. Quantitative extraction using an internally cooled solid-phase micro-extraction device. Anal. Chem. 67: 34-43.