Sains Malaysiana 33(1): 99-107 (2004)                                                                                         Sains Hayat /

Life Science

Influence of Inlet Air Temperature and Feed Flow Rate on the Physical Properties of Spray-dried Mengkudu (Morinda citrifolia) Extract

Mohamad Yusof Maskat & Yeow Lee Ling

Food Science Program

Schaal of Chemical Sciences and Food Technology

Faculty of Science and Technology

Universiti Kebangsaan Malaysia

43600 UKM Bangi, Selangor D.E.,,Malaysia

ABSTRACT

Due to the increase in consumer interest, mengkudu (Morinda citrifolia) extract is being produced in several forms including dry powder. One of the methods that can be used to produce dry powder is spray drying. This study was done to determine the physical properties of powdered mengkudu extract produced by spray drying from different sections of the spray-dryer. Mengkudu extract at 50% (v/v) dilution was spray-dried using two levels of feed flow rate (350 mL/hr and 475 mL/hr) and inlet air temperature (170^oC and 190^oC).  Spray dried mengkudu extract from the cyclone and colletion sections of the spray dryer was collected and analyzed for amount produced, moisture content and colour. No significant interaction between feed flow rate and inlet air temperature used was observed for all parameters measured. Inlet temperature used did not show any significant effect on amount of production.  However, increasing the inlet air temperature from 170^oC to 190^oC did produce  lower moisture content for samples from the cyclone  but no significant difference for samples from the collection bottle, while lowering the degree of redness of samples from the collection bottle, while lowering the degree of brightness for samples from both cyclone and collection sections of the spray-dryer. Feed flow rate used did not produce any significant effect on all parameters measured.

ABSTRAK

Peningkatan minat pengguna terhadap ekstrak mengkudu telah menyebabkan ianya dihasilkan dalam pelbagai bentuk termasuk serbuk. Antara kaedah yang boleh digunakan untuk penghasilan serbuk mengkudu adalah kaedah pengeringan semburan. Kajian ini telah dijalankan untuk menentukan ciri fizikal serbuk mengkudu yang dihasilkan melalui pengeringan semburan dari bahagian pengering semburan yang berbeza. Ekstrak mengkudu pada pencairan 50% (v/v) telah dilakukan pengeringan semburan menggunakan dua tahap kadar suapan (350 mL/j dan 475 mL/j) dan suhu udara masuk (170^oC dan 190^oC). Ekstrak mengkudu yang telah dikeringkan dari bahagian botol pengumpul dan siklon dianalisa untuk jumlah penghasilan, kandungan lembapan dan parameter warna. Tiada interaksi yang signifikan di antara suhu udara masuk dan kadar suapan telah didapati untuk semua parameter yang diukur. Suhu udara masuk tidak menunjukkan kesan signifikan terhadap jumlah penghasilan. Tetapi, peningkatan suhu udara masuk dari 170^oC kepada 190^oC menghasilkan kandungan lembapan yang lebih rendah bagi sampel dari bahagian siklon tetapi tidak untuk bahagian botol pengumpul. Peningkatan suhu udara masuk dari 170^oC kepada 190^oC juga meningkatkan darjah kemerahan sampel dari botol pengumpul serta menurunkan darjah kecerahan bagi sampel dari kedua-dua botol pengumpul dan siklon. Kadar suapan yang digunakan didapati tidak menghasilkan kesan yang signifikan terhadap semua parameter yang diukur.

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