The influence of pasteurization and starter culture on methanol content and bio-profile of fermented Morinda citrifolia Linn. (Noni) fruit juice

Abstract

Morinda citrifolia L., generally known as noni, is commonly used in Thai medicines and cuisine. Several bioactive phytochemicals have been isolated and identified from the noni plant, and their compositions differ based on the cultivars and harvesting period. Different types of fermented noni fruit juices (FNJ) were used as health supplement in several southeastern countries. The formation of a large amount of alcohol, especially methanol, in FNJ is one of the major hindrances to FNJ production. The current study explains the impact of starter culture (Lactobacillus plantarum SK15), pasteurization and addition of EGCG on alcohol content, bioactivity, and the physiochemical property of FNJ. The pH and sugar content of the samples were reduced during fermentation, while the organic acid content increased. The samples with EGCG obviously exhibited high total phenolic content and antioxidant activity. The level of pectin was high, and pectin methylesterase (PME) activity was low in EGCG-added samples compared with other samples. The alcohol content of the samples was under the permissible level of Thai standard; specifically, the methanol level was low in EGCG-added samples. Pasteurization and addition of starter culture did not influence any of the studied parameters. About 70% of acceptability index was observed for FNJ samples in the sensory evaluation. The study concluded that the addition of EGCG effectively reduced the alcohol content and improved the quality of FNJ. Also, further studies are required to reveal the role of starter culture in noni fruit fermentation.Practical Application: The production of enriched bioactive fermented noni fruit juice with low alcohol content.

Changes in Bioactive Compounds of Coffee Pulp through Fermentation-Based Biotransformation Using Lactobacillus plantarum TISTR 543 and Its Antioxidant Activities

“…One loopful of L. plantarum stock was inoculated on preculture de Man, Rogosa, and Sharpe (MRS) agar plate and incubated at 30 ± 2 • C for 48 h. The obtained single colony was then transferred to MRS broth and incubated at 30 ± 2 • C for 24 h, to obtain an approximate cell concentration of 10 9 CFU/mL. The inoculum was prepared in the range of 5-15 % for coffee pulp fermentation [18].…”

“…After cooling, the sterilized substrates were inoculated with a starter culture (10 9 CFU/mL stock) under aseptic conditions, as seen in Table 2. The resultant flasks were incubated at 30 • C for the fermentation process, and samples were collected to assess the total phenolic content [18].…”

“…Conventional microbiological methods were used to evaluate the microbial enumeration. Microbial counts of LAB were measured by serial dilution and plate count method using a previously described protocol [18]. LAB was incubated at 30 • C for 48 h under anaerobic conditions.…”

“…Total phenolics content was determined by the Folin-Ciocalteu method, which was adapted from the method described by Saelee et al [18]. Briefly, 80 µL of the fermented cof-fee pulp sample at the appropriate dilution was incubated with 20 µL of Folin-Ciocalteu's reagent and 100 µL of 7.5% Na 2 CO 3 solution, respectively.…”

“…The DPPH assay was done based on a previously stated protocol [18] to determine the antioxidant capacity of coffee pulp extract at different fermentation stages. The DPPH activity of coffee pulp extract was evaluated before (control) and after treatments.…”