IDENTIFICATION OF LACTIC ACID BACTERIA FROM CHROUK SPEY, A TRADITIONAL CAMBODIAN FERMENTED FOOD AND STANDARDIZATION FOR CONTROLLED FERMENTATION

• Main Author: Chandavy, Seng
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/35878
• Institution: Institut Teknologi Bandung

A sour pickled mustard greens known as Chrouk spey is one of the most popular fermented vegetable in Cambodia. Naturally occur of Lactic Acid Bacteria (LAB) from the raw ingredients play an important role in the fermentation of Chrouk spey. LAB diversity in the fermentation of mustard greens vegetable has not been widely understood. Moreover, unsuccessful development of sour taste and different quality of end-product are the major problems for this sour pickled fermentation. Therefore, this study aims to isolate and to identify LAB from Chrouk spey and to control the fermentation by using dominant LAB as starter culture. The mustard greens vegetables were naturally fermented in room temperature for seven days. LAB were isolated on MRS (de Man, Rogosa, and Sharpe) agar supplemented with 1% (w/v) CaCO3 at day 1-7 of fermentation. The clear zone colonies were randomly selected for catalase test and Gram staining. Sixteen isolates with catalase negative and Gram positive were assumed as LAB and 5 representative isolates were further identified by 16S rRNA gene sequencing. Sequencing analysis revealed the LAB species were dominated by genus Weissella (Weissella cibaria, Weissella sp. and Weissella confusa). One dominant Weissella strain was used as a starter culture. Standardization experiment was conducted in 3 batches of fermentation, control batch without starter culture and culture-added batches 5 % (v/v) and 7% (v/v). At the beginning of the fermentation (day 1), the pH of all batches were similar in the range of 5.1 to 5.7. At the end of fermentation (day 7), the 7% (v/v) inoculum batch had the lowest pH 3.2 and the 5% (v/v) inoculum batch had the pH 3.5, while the control batch without starter culture had the highest pH 3.7. Total acid in natural fermentation increased from 0.041% to 0.142%, in 5% inoculum batch increased from 0.049% to 0.15% and in 7% inoculum batch increased from 0.054% to 0.21%. Range of total LAB population in natural fermentation are 5.9 – 6.39 logCFU/mL, in 5% (v/v) inoculum are 5.95 – 6.44 logCFU/mL and in 7% (v/v) inoculum are 6.27 – 6.3 logCFU/mL.