PENGARUH SUHU DAN LAMA PENYIMPANAN TEMPE TERHADAP PRODUKSI BAKTERIOSIN DAN TOTAL ASAM ORGANIK SEBAGAI ICANDIDAT PENGAWET MAKANAN

• Main Author: Ihsan Febrian, Rizki
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/64364
• Institution: Institut Teknologi Bandung

Tempeh is a fermented food product that contains lactic acid bacteria. This bacteria has been known to produce bacteriocins and lactic acid showing antimicrobial activity. Therefore, tempeh is potential to be developed as a source of natural food preservative. The aim of this research was to obtain data showing the influence of temperature and storage time of tempeh on the bacteriocin and organic acid production, as well as antimicrobial activity of both substances. Three tempeh samples were stored at different temperatures and storage time, i.e. fresh tempeh (sample A), tempeh that has been stored for two days at room temperature (sample B), and tempeh that has been stored for two days in refrigerator at 4 °C (sample C). Lactic acid bacteria were isolated and identified from three samples. Total Plate Count (TPC) of bacteria several isolates used to produce bacteriocins and organic acid containing supernatants was determined. The assays of bacteriocin activity were performed using cross streak and agar diffusion method, whereas the determination of total organic acid was performed using acid-base titration method. Antibacterial activity of supernatant of each sample was tested by determination of Minimum Inhibitory Concentration (MIC) using a microdilution method. Isolates obtained from the three tempeh samples contain Gram-positive bacteria, possibly Lactobacillus easel. TPC of bacteria in isolates from samples A, B, and C were, 6.1 x 10', 7.6 x KC, and 7.0 x 107 CFU/mL, respectively. Supernatan from samples A, B, and C showed bacteriocin activity, but did not show any significant differences, with the total organic acid contents of respectively 94.3 ± 2.1, 55.5 ± 1.0, and 84.3 ± 2.4 mmol/L. In the supernatant concentration range of, 1 to 512 ug/mL, no inhibition of bacterial growth was observed and hence no MIC could be determine. Temperature and storage time of tempeh influence TPC of bacteria, in which tempeh that has been stored for two days at room temperature showed the highest TPC, whereas fresh tempeh showed the lowest TPC. Fresh tempeh sample showed the highest total organic acid content, whereas tempeh that has been stored for two days at room temperature showed the lowest total organic acid content. However, these differences were not accompanied by differences in bacteriocin activity. In the concentration range of 1 to 512 ktg/mL, supernatant from three tempeh samples showed no inhibition of bacterial growth.