Pengaruh fosfolipid terhadap titik isoelektrik dan kadar protein tahu dengan bahan penggumpal asam asetat

Abstract

Sifat pengemulsi dari fosfolipid santan kelapa dapat mempengaruhi titik isoelektrik dan kadar protein tahu karena fosfolipid memiliki gugus polar dan nonpolar yang dapat berinteraksi dengan protein kedelai. Penelitian ini bertujuan untuk menentukan pengaruh fosfolipid pada titik isoelektrik dan kadar protein tahu dengan bahan penggumpal asam asetat. Mula¬mula ditentukan titik isoelektrik tahu tanpa fosfolipid, setelah itu ditentukan pengaruh fosfolipid pada titik isoelektrik dan kadar protein tahu dengan variasi volume penambahan fosfolipid pada pH isoelektrik yaitu 0,0; 0,5; 1,0; 1,5; 2,0 dan 2,5 mL dan variasi pH pada konsentrasi fosfolipid 2,0 mL dalam 50 mL sari kedelai, yaitu pada pH 4,0; 4,1; 4,2; 4,3; 4,4; dan 4,5. Untuk penentuan kadar protein dilakukan dengan metode Lowry. Dari hasil yang diperoleh disimpulkan keberadaan fosfolipid menurunkan kadar protein tahu dan cenderung tidak menggeser titik isoelektrik atau pH isoelektrik yaitu pH = 4,4. Background of the invention is emulsifier characteristic of phospholipid can be influence to isoelectrical point and protein concentration of tofu because phospholipid has polar and nonpolar functional groups that can interact with tofu proteins. The research was carried out determine the influence of phospholipid on isoelectrical point and protein concentration of tofu with coagulant acetic acid. The first step is carried out isoelectric's pH without phospholipid, then carried out the influence of phospholipid to isoelectrical point and tofu's protein concentration at phospholipid concentrate variation 0.0; 0.5; 1.0; 1.5; 2.0 and 2.5 mL at isoelectrical point and pH variation to 2.0 mL phospholipids in 50 mL soybeans essence at 4.0; 4.1; 4.2; 4.3; 4.4; and 4.5. The effect of phospholipid was determined by tofu's protein mass and tofu's protein concentration. Tofu protein concentrate was determined by absorbance of tofu's supernatan with Lowry method. From experiment we got the conclusions that phospholipid decreasing tofu's proteins and tend to not moving the isoelectrical point at pH = 4.4. .... UtiNneitsj agree may, witnout cnanging the content, translate the submission to any medium or format for the purpose of preservation. The author(s) or copyright owner(s) also agree that UNDIP-IR may keep more than one copy of this submission for purposes of security, back-up and preservation. ( http://eprints.undip.ac.id)