Ekstraksi, Isolasi, dan Karakterisasi Sifat Fisikokimia Protein Kacang Koro Pedang Putih sebagai Kandidat Bahan Plant-Based Meat

Abstract

Kacang koro pedang (KKP) memiliki potensi besar untuk dikembangkan sebagai alternatif sumber protein yang menggantikan protein hewani. Namun demikian, serangkaian proses diperlukan untuk mengekstrak dan mengisolasi protein dari KKP sehingga diperoleh sediaan protein KKP dalam bentuk konsentrat atau isolat. Tujuan penelitian ini adalah mengekstraksi dan mengisolasi protein KKP serta menganalisis sifat fisikokimia isolat protein KKP yang dapat digunakan sebagai parameter evaluasi apakah isolat protein KKP berpotensi sebagai kandidat bahan plant-based meat. Tahapan untuk menghasilkan protein KKP meliputi screening proses untuk menurunkan kadar asam sianida (HCN) pada tepung KKP, proses penepungan, defatting, screening bufer untuk proses ekstraksi, screening isoelectric point (IEP) untuk proses isolasi protein, dan freeze drying. Analisis sifat-sifat fisikokimia isolat protein meliputi kadar HCN, analisis proksimat, rendemen, kadar protein terlarut, protein nativity dengan differential scanning calorimetry (DSC), analisis pembentukan nanofibril dan gel. Hasil penelitian menunjukkan bahwa perlakuan blanching sebelum perendaman KKP menghasilkan tepung dengan kadar HCN terendah, yaitu 23,66 ppm. Metode ekstraksi protein terbaik dilakukan dengan larutan NaOH pH 8,5 pada suhu 40 °C (Bufer #2). IEP Bufer #2 untuk isolasi protein adalah pH 4,0. Metode-metode tersebut menghasilkan protein (as crude protein) dengan kadar 94,24% basis kering sehingga dikategorikan sebagai isolat protein, sedangkan kadar protein terlarutnya sebesar 71,09%. Isolat protein KKP yang dihasilkan memiliki kadar HCN 30,358 ppm. Analisis DSC menunjukkan bahwa isolat protein masih memiliki protein nativity setelah melalui rangkaian proses ekstraksi dan isolasi. Larutan isolat protein KKP pada konsentrasi 2% w/w pH 2,0 setelah dipanaskan pada 90 °C selama 20 jam secara visual tidak dapat membentuk nanofibril. Peningkatan konsentrasi menjadi 4% w/w menghasilkan gel pada pH 2,0 dan 3,0 setelah pemanasan yang dilanjutkan dengan pendinginan.

Jack bean (Canavalia ensiformis) has a great potential to be developed as an alternative source of protein that replaces animal protein. However, a series of processes are required to extract and isolate the protein from jack bean, therefore jack bean protein concentrate, or isolate is obtained. The purpose of this study was to extract and isolate jack bean protein and analyze the physicochemical properties of jack bean protein isolate that can be used as evaluation parameters whether jack bean protein has a potential as a candidate for plant-based meat ingredients. The stages to produce jack bean protein include screening process to reduce hydrogen cyanide (HCN) levels in jack bean flour, milling process, defatting, buffer screening for extraction process, isoelectric point (IEP) screening for protein isolation process, and freeze drying. Analysis of the physicochemical properties of protein isolate includes HCN content, proximate analysis, yield, soluble protein content, protein nativity with differential scanning calorimetry (DSC), nanofibril and gel formation analysis. The results showed that blanching before soaking jack bean resulted in flour with the lowest HCN content, which was 23.66 ppm. The best method of protein extraction was carried out with NaOH solution pH 8.5 at 40 °C (Buffer #2). IEP Buffer #2 for protein isolation was pH 4.0. These methods produced protein (as crude protein) with a content of 94.24% on dry basis, which was categorized as protein isolate, while its soluble protein content was 71.09%. The resulting jack bean protein isolate had an HCN content of 30,358 ppm. DSC analysis showed that the protein isolates still kept a certain level of protein nativity after going through a series of extraction and isolation processes. The solution of jack bean protein isolates at a concentration of 2% w/w pH 2.0 after heating at 90 °C for 20 h could not form nanofibrils visually. Increasing the concentration to 4% w/w at pH 2.0 and pH 3.0 resulted in gel formation after heating followed by cooling.