Sifat Fungsional Yoghurt Susu Kambing Probiotik yang Diperkaya Ekstrak Bunga Rosela (Hibiscus Sabdariffa L) sebagai Antimikroba dan Antihipertensi

Abstract

Goat milk has several advantages over cow milk. Despite its advantages, goat milk has limitations in term of short shelf life and goaty odor. To overcome these limitations, in this research, the goat milk was processed into yoghurt. To improve its quality, a probiotic bacterium isolated from Indonesian cattle, Lactobacillus acidophillus IIA-2B4, and roselle extract were added to the yoghurt. Total lactic acid bacteria (LAB) in yoghurt with addition of L. acidophilus IIA-2B4 with or without roselle extract is significantly higher compared to the control. The high population of LAB in yoghurt with addition of L. acidophilus IIA-2B4 with or without roselle extract is proportional to the acidity of the product that promotes higher viscosity compared to the control. Proximate analysis revealed that additions of L. acidophilus IIA-2B4 and/or roselle extract significantly reduce fat content, while ash content is significantly increased by the treatments. SDS-Page revealed that addition of L. acidophilus IIA-2B4 with/without roselle extract produces <10 kDa peptides. These fragments display remarkable antimicrobial activity and antihypertensive. Antibacterial activity assay demonstrated that goat milk yoghurt is able to inhibit both Gram positive and negative bacteria with high selectivity towards Gram positive bacteria. Addition of L. acidophilus IIA-2B4 with or without roselle extract increases the ability of yoghurt to inhibit Gram negative bacteria. This ability might be due to the presence of peptides exhibiting antimicrobial activity produced during fermentation by probiotic. Antihypertensive demonstrated that goat milk yoghurt is able to inhibit the angiotensin converting enzyme (ACE) activity an enzyme that plays a role in the renin angiotensin aldosterone system as a function of blood pressure regulation in human body.