Increasing the Protein Content of Horse Milk (Equus caballus) through Cheese Processing with Addition of a Mixed Starter Culture (Lactobacillus lactis and Lactobacillus bulgaricus)

Indah Zahara Sagala (Sagala)
Rizki Amelia Nasution (Universitas Islam Negeri Sumatera Utara)
Rasyidah Rasyidah (Universitas Islam Negeri Sumatera Utara)

Jurnal Biologi Tropis
Vol. 26 No. 4 (2026): in Progress

Horse milk (Equus caballus) is a type of milk high in vitamin C, vitamin B, and calcium. However, its protein content is relatively low, at 1.5%–2.5%. To increase the protein content of horse milk, it is processed into cheese products. The purpose of this study was to increase the protein content of horse milk through processed cheese products using Lactobacillus lactis and Lactobacillus bulgaricus starter cultures. This study was conducted experimentally with four treatments: control, 6% Lactobacillus bulgaricus, 6% Lactobacillus lactis, and 3% Lactobacillus bulgaricus + 3% Lactobacillus lactis, with three shelf lives (1, 7, and 14 days). Protein levels were analyzed using the Kjeldahl method. The results showed that protein levels increased significantly, with the highest value of 39.98% on the 14th day of storage in the Lactobacillus bulgaricus 3% + Lactobacillus lactis 3% treatment. The conclusion of this study is that the process of fermenting mare's milk into cheese with the addition of Lactobacillus bulgaricus 3% + Lactobacillus lactis 3% starter is very effective in increasing protein levels and producing high-protein cheese.