Isolasi Protein Kacang Koro (Phaseolus lunatus L.) dan Penetapan Kadar Protein dengan Metode Kjeldahl dan Bradford

Abstract

Background: Jack beans have a protein content of 14,4%-26,4%. One alternative to obtain isolated protein from jack beans is through the acid- base method. Protein content can be measured quantitatively using the Kjeldahl and Bradford methods. Objective: The purpose of this study is to use the Kjeldahl and Bradford method to determine the amount of protein isolat content in koro beans (Phaseolus lunatus L.). Method: Jack beans were extracted using NaOH to pH 10 then followed by a precipitation process with HCl to pH 4-4.5. Then centrifuged at a speed of 3500 rpm for 30 minutes at a temperature of 4˚C. The sediment resulting from centrifugation was taken and dried using an oven. Determination of protein levels was carried out using the Kjeldahl method and the Bradford method. Results: The results of the isolation of koro bean protein using HCl obtained an isolate of 0.6 grams from a sample weight of 10 grams with a yield of 5.82%. The protein content of jack bean using the Kjeldahl method is 0,11%. Meanwhile, the protein content of jack beans using the Bradford method is 6,07%. Conclusion: There is a difference between the jack bean protein isolate using the Kjeldahl method and the Bradford method. Namely the Bradford method had a higher protein content than the Kjeldahl method.