Sains Malaysiana 33(1): 63-72 (2004)                                                                                           Sains Hayat /

Life Science

Penghasilan Hidrolisat Protein Kuning

Telur Melalui Hidrolisis Berasid

(Production of egg yolk protein hydrolysate

through acid hydrolysis)

Wan Aida Wan Mustapha & Su Koh Shin

Program Sains Makanan

Pusat Pengajian Sains Kimia dan Teknologi Makanan

Fakulti Sains dan Teknologi

Universiti Kebangsaan Malaysia

43600 UKM Bangi Selangor D.E., Malaysia

ABSTRAK

Kandungan kuning telur luar gred yang melebihi 50% daripada telur biasa didapati sesuai untuk digunakan dalam pemprosesan perisa hidrolisat. Pengekstrakan protein dilakukan dengan mengguna etanol dan air pada dua nisbah berbeza iaitu 1:1:1 dan 1:5:2 (kuning telur : etanol : air). Protein kuning telur di hidrolisis menggunakan 3N dan 5N asid hidroklorik selama 10 jam pada suhu 110^oC. Hasil akhir hidrolisat protein dikeringkan secara semburan sejuk-beku. Hasil kajian mendapati pengekstraksian menggunakan nisbah 1:5:2 memberikan kandungan protein yang paling tinggi. Hidrolisat protein dengan perlakuan 5N asid hidroklorik mempunyai darjah hidrolisis yang paling tinggi. Sampel gabungan 1:5:2 - 5N memberikan darjah hidrolisis tertinggi (78.3%) diikuti oleh gabungan 1:1:1 -5N (69.4%) dan 1:5:2 - 3N (66.9%). Hasil penilaian sensori menunjukkan sampel 5:2 - 3N memberikan kekuatan aroma yang tertinggi di antara keempat-empat sampel. Sebatian aroma yang dihasilkan daripada hidrolisat kuning telur lebih menyerupai pati ayam Brands atau ekstrak lembu Brovil di mana kehadiran sebatian­-sebatian kumpulan amina, alkohol, alkana, indol dan fenol telah dikesan menggunakan Kromatografi Gas ruang tutupan.

ABSTRACT

Off grade egg with egg yolk content of 50% higher than normal egg can be successfully used in processing of hydrolysate flavourings. Protein extrac­tion using ethanol with two different ratios of egg yolk: ethanol: water ( 1: 1: 1 and 1:5:2) was carried out. The egg yolk protein was hydrolysed with 3N and 5N HCI for 10 hours at 11 ()'C. The protein hydrolysate obtained was freeze­ dried. Studies showed that extraction using 1:5:2 ratio gave the highest protein content. The protein hydrolysate treated with 5N HCI gave the highest degree of hydrolysis. Sample of 1:5:2 - 5N had the highest degree of hydrolysis (78.8%),followed by sample of 1:1:1-5N (69.4%) and 1:5:2 - 3N (66.9%). Sensory evaluation results showed that sample of 1:5:2 - 3N produced the strongest aroma among the four samples studied. Aroma of egg yolk protein hydrolysate was similar to Brands Chicken Essence or Brovil Beef Extract.  The presence of volatile compounds with amine chemical groups, alcohol, alkane, indole and phenol were detected using headspace Gas Chromatography.

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