METHODS: the potential of developing natural disinfectant while using watermelon rinds (WR), pineapple (PP), orange peels (OP), palm kernel cake (PKC), and rice bran (RB), via lacto-fermentation was investigated. The obtained lactic acid bacteria (LAB) metabolites were then employed and the in vitro antifungal activity toward five spoilage fungi of mango was tested through liquid and solid systems. Besides, the effect of the produced disinfectant on the fungal growth inhibition and quality of mango was investigated.
RESULTS: the strains Lactobacillus plantarum ATCC8014 and Lactobacillus fermentum ATCC9338 growing in the substrates PKC and PP exhibited significantly higher in vitro antifungal activity against Colletotrichum gloeosporioides and Botryodiplodia theobromae as compared to other tested LAB strains and substrates. The in-situ results demonstrated that mango samples that were treated with the disinfectant produced from PKC fermented with L. plantarum and L. fermentum had the lowest disease incidence and disease severity index after 16 days shelf life, as well as the lowest conidial concentration. Furthermore, PKC that was fermented by L. fermentum highly maintained the quality of the mango.
CONCLUSIONS: lactic acid fermentation of PKC by L. fermentum demonstrated a high potential for use as a natural disinfectant to control C. gloeosporioides and B. theobromae on mango.
Materials and Methods: The study started with the identification of selected LAB by 16S rRNA, followed by optimization of GABA production by culture conditions using different initial pH, temperature, glutamate concentration, incubation time, carbon, and nitrogen sources. 16S rRNA polymerase chain reaction and analysis by phylogenetic were used to identify Lactobacillus plantarum (coded as N5) responsible for the production of GABA.
Results: GABA production by high-performance liquid chromatography was highest at pH of 5.5, temperature of 36°C, glutamate concentration of 500 mM, and incubation time of 84 h. Peptone and glucose served as the nitrogen and carbon sources, respectively, whereas GABA was produced at optimum fermentation condition of 211.169 mM.
Conclusion: Production of GABA by L. plantarum N5 was influenced by initial pH of 5.5, glutamic acid concentration, nitrogen source, glucose as carbon source, and incubation temperature and time.
RESULTS: Postbiotic supplementation increased weight gain, feed intake, nutrient intake and nutrient digestibility of the lambs. No effect on ruminal pH and total VFA, whereas butyrate and ruminal ammonia-N concentration were improved. The lambs fed with postbiotics had higher blood total protein, urea nitrogen and glucose. However, no difference was observed in blood triglycerides and cholesterol levels. Postbiotics increased the population of fibre degrading bacteria but decreased total protozoa and methanogens in rumen. Postbiotics increased the mRNA expression of hepatic IGF-1 and ruminal MCT-1.
CONCLUSIONS: The inclusion of postbiotics from L. plantarum RG14 in newly-weaned lambs improved growth performance, nutrient intake and nutrient digestibility reflected from better rumen fermentation and microbial parameters, blood metabolites and upregulation of growth and nutrient intake genes in the post-weaning lambs.