Sains Malaysiana 41(4)(2012): 411-418

Kesan Penambahan Kalsium Karbonat dan Sukrosa ke Atas Ciri Ekstrak Roselle

Menggunakan Kaedah Respon Permukaan

(Effect of Calcium Carbonate and Sucrose Addition on the Properties of Roselle

Extract Using Response Surface Methodology)

Wan Zawiah Wan Abdullah

Jabatan Agroteknologi, Fakulti Agroteknologi dan Sains Makanan , Universiti MalaysiaTerengganu

21030 Kuala Terengganu, Terengganu Darul Iman, Malaysia

Md Zaidi Yahaya

Jabatan Sains Makanan, Fakulti Agroteknologi dan Sains Makanan, Universiti Malaysia Terengganu

21030 Kuala Terengganum, Terengganu Darul Iman, Malaysia

Mohamad Yusof Maskat*

Pusat Pengajian Kimia dan Teknologi Makanan, Fakulti Sains dan Teknologi,

Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor D.E. Malaysia

Received: 3 Jun 2011 / Accepted: 30 September 2011

ABSTRAK

This study was conducted to determine the effect of calcium carbonate (CaCO₃) and sucrose addition on roselle extract using Response Surface Methodology. A total of 21 treatments were used based on a Central Composite Rotatable Design (CCRD). Determination of pH and Brix were carried out. For pH, the model used was 4.03+0.39x₁-8.20x₂-0.05x₁²-4.16x₂²-0.02x₁x₂ where x₁ is calcium carbonate and x₂ is sucrose. The positive coefficient for calcium carbonate showed addition of calcium increased pH of the roselle extract. Model for Brix is 8.91 + 0.23x₁ + 2.20x₂. The positive coefficient for calcium carbonate and sucrose showed the addition of calcium carbonate and sucrose increased the degree of Brix of the roselle extract. Sensory evaluation using trained panelists (n=8) showed addition of sucrose increased overall acceptance for roselle extract. Addition of calcium carbonate reduced the overall acceptance due to the lowering of the sour taste.

Keyword: Calcium carbonate; Response Surface Methodology; roselle; sucrose

ABSTRAK

Kajian ini dijalankan bagi menentukan kesan penambahan kalsium karbonat (CaCO₃) dan sukrosa ke atas ekstrak roselle dengan menggunakan Kaedah Respon Permukaan. Sebanyak 21 perlakuan digunakan berdasarkan reka bentuk eksperimen Central Composite Rotatable Design (CCRD). Penentuan nilai pH dan Briks telah dijalankan. Bagi nilai pH, model yang didapati adalah 4.03+0.39x₁-8.20x₂-0.05x₁²-4.16x₂²-0.02x₁x₂ dengan nilai x₁ adalah kalsium karbonat dan nilai x₂ adalah sukrosa. Nilai positif pada kepekatan kalsium menunjukkan penambahan kalsium meningkatkan nilai pH ekstrak roselle. Model untuk Briks adalah 8.91 + 0.23x₁ + 2.20x₂. Nilai positif pada kepekatan kalsium dan sukrosa menunjukkan penambahan kalsium dan sukrosa meningkatkan nilai Briks ekstrak roselle. Penilaian sensori dengan menggunakan panel terlatih (n=8) menunjukkan penambahan sukrosa meningkatkan penerimaan keseluruhan terhadap ekstrak Roselle. Manakala, kesan penambahan kalsium karbonat telah mengurangkan penerimaan keseluruhan kerana ia merendahkan rasa masam.

Kata kunci : Kaedah respon permukaan; kalsium karbonat; roselle; sukrosa

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*Corresponding author; email: maskatmy@yahoo.com