SENSORY CHARACTERISTICS OF MUD CLAM (Polymesoda erosa) HYDROLYSATE

Abstract

Mud clam (Polymesoda erosa) was hydrolysed using two different microbial enzymes; alcalase and flavourzyme. The volatile compounds, amino acids and molecular weight associated with umami and bitter taste in mud clam hydrolysate were determined by head space solid phase micro-extraction gas chromatography (HS-SPME-GCMS), High performance liquid chromatography (HPLC) and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The characteristics of hydrolysates produced using alcalase and flavourzyme were compared. In total, eighteen, seven and six volatile compounds were identified in the flesh, alcalase hydrolysate and flavourzyme hydrolysate, respectively. 2-piperidinone volatile compound content which is associated with bitterness was 6.79 % in alcalase hydrolysate and 3.78 % in flavourzyme hydrolysate. SDS-PAGE results showed that alcalase hydrolysate contains smaller peptide (<52 kDa) compared to flavourzyme hydrolysate (<126 kDa). In addition, sensory analysis using quantitative descriptive analysis (QDA) showed that flavourzyme hydroysate was the least bitter but elicited more umami taste compared to alcalase hydrolysate. Further treatments are still needed to enhance umami taste and to remove bitter taste in mud clam hydrolysate.Keywords: mud clam hydrolysate, volatile compounds, amino acids, molecular weight, sensory Abstrak Lokan (Polymesoda erosa) telah dihidrolisiskan menggunakan dua microbial enzim yang berbeza; alcalase dan flavourzyme. Sebatian meruap, asid amino dan berat molekul yang dikaitkan dengan umami dan rasa pahit di dalam hidrolisat lokan ditentukan oleh ruang kepala pepejal mikro fasa kromatografi gas (HS-SPME-GCMS), cecair kromatografi berprestasi tinggi (HPLC) dan elektroforesis gel sodium dodekil sulfat poliakrimida (SDS-PAGE). Ciri -ciri hidrolisat dihasilkan menggunakan alcalase dan flavourzyme dibandingkan. Secara keseluruhan, lapan belas, tujuh dan enam sebatian meruap telah dikenal pasti dalam masing -masing pada isi lokan, hidrolisat alcalase dan hidrolisat flavourzyme. Kandungan sebatian meruap; 2-piperidinone yang dikaitkan dengan kepahitan adalah 6.79 % pada hidrolisat alcalase dan 3.78 % pada hidrolisat flavourzyme. Keputusan SDS-PAGE menunjukkan hidrolisat alcalase mengandungi peptida yang lebih kecil (<52 kDa) berbanding hidrolisat flavourzyme (<126 kDa). Di samping itu, analisis deria menggunakan kuantitatif deskriptif analisis (QDA) menunjukkan bahawa hidrolisat flavourzyme adalah yang paling kurang pahit dan memberi rasa umami yang lebih berbanding hidrolisat alcalase. Penambahbaikan lanjut masih diperlukan untuk meningkatkan rasa umami dan untuk menghilangkan rasa pahit dalam hidrolisat lokan.Kata kunci: hidrolisat lokan, sebatian meruap, asid amino, berat molekul, deria

Ảnh hưởng của độ mặn đến sinh trưởng và tỷ lệ sống của vọp (Geloina coaxans)

“…Vọp (Geloina coaxans) là loài nhuyễn thể có kích cỡ thương phẩm lớn, ngày càng được ưa chuộng do hàm lượng protein cao và chất lượng thịt thơm ngon (Ismail, 2015). Vọp còn được biết tới với tên gọi nghêu rừng đước, nghêu bùn hay vọp sông.…”