Difusivitas Panas dan Umur Simpan Pempek Lenjer

The objectives of this research were to study the effect of fish and flour formulation as well as centre point temperature on the thermal diffusivity and shelf life of pempek lenjer. The parameters observed were the temperature of pempek at several position: i.e. (r0) = 0 cm, r1 = 1 cm, r2 = 2 cm, cooking time, change of textural value, total volatile nitrogen and total microbes of pempek during storage. Data temperaturedistribution was analyzed by using diffusivity at center point model, and random diffusivity models through computer program of Engineering Equation Solver (EES) Ver 8.91. The shelf life data was analyzed by usinglinear regression to determine the relationship between storage time and the measured variables which was followed by calculating using Arrhenius method to compare the decrease of pempek lenjer quality. The results showed that thermal diffusivity coefficient of pempek lenjer for formula 1 was in the range of 0.321 to 1.515 .10-7 m2/s, for formula 2 was in the range of 0.297 to 1.389.10-7 m2/s, for formula 3 was in the rangeof 0.378 to 1.471 . 10-7 m2/s and for formula 4 was in the range of 0.2778 to 1.620.10-7 m2/s.The research results showedthat longerstorage time results in lower values of texture, but produced higher value oftotal volatile nitrogen and total microbes. The lowest Eavaluefrom the measured variablewas totalmicrobes which can be used as the main parameter of deterioration for pempek lenjer during storage. The shelf lifeof pempek lenjer based on total microbes value was in the range of 27 to 33 hour

Penentuan Difusivitas Panas Pempek Lenjer Selama Perebusan Menggunakan Metode Numeri

Koefisien difusivitas panas pada perebusan pempek lenjer harus diketahui, karena dapat ditentukan waktu pengolahan pempek yang tepat (optimal). Formula dan suhu akan mempengaruhi koefisien difusivitas panas.Tujuan penelitian adalah menentukan koefisien difusivitas panas pada perebusan pempek lenjer secara numerik. Variabel yang diukur adalah suhu sampel pada titik pusat (r0) = 0 cm, r1= 1 cm, r2= 2 cm, dan lama pemasakan pempek. Data yang diperoleh dianalisis menggunakan model difusivitas panas di titik sembarang dan model difusivitas panas di titik pusat, dengan program computer Engineering Equation Solver (EES) Ver 8.91.Hasil penelitian menunjukkan bahwa koefisien difusivitas panas pempek lenjer pada formula 1 adalah interval 0,321 - 1,515. 10-7 m/s, pada formula 2 adalah 0,297 - 1,389. 10-7 m2/s, pada formula 3 adalah 0,378 - 1,471. 10-7 m/s, dan formula 4 adalah 0,2778 - 1,620. 10-7 m2/s