Evaluation of gallic acid on membrane damage of Yersinia enterocolitica and its application as a food preservative in pork

Nutritional profiling, fiber content and in vitro bioactivities of wheat-based biscuits formulated with novel ingredients

This study evaluated the nutritional profile and fiber content of innovative formulations of wheat-based biscuits enriched with chia seeds, carob flour and coconut sugar. The in vitro antioxidant, cytotoxic, anti-inflammatory and antimicrobial activities were also investigated to understand the potential health advantages of the incorporation of these new ingredients. The novel biscuits demonstrated significant improvements in protein and mineral content, with increases of 50% and 100% in chia biscuits, and up to 20% and 40% in carob biscuits, respectively. Fiber also notably increased, particularly in samples containing 10% carob flour, which increased four times as compared to wheat-based samples. The new ingredients exhibited antibacterial and antifungal activity, particularly against Yersinia enterocolitica (minimum inhibitory concentration 1.25 mg mL-1 in coconut sugar) and Aspergillus fumigatus (minimum inhibitory concentration/minimum fungicidal concentrations 2.5/5 mg mL-1 in chia seeds). However, the final biscuits only displayed antifungal properties. Carob flour and chia seeds had a remarkably high capacity to inhibit the formation of TBARS and promoted greater antioxidant activity in biscuit formulations, with EC50 values decreasing from 23.25 mg mL-1 (control) to 4.54 mg mL-1 (15% defatted ground chia seeds) and 1.19 mg mL-1 (10% carob flour). Only chia seeds exhibited cellular antioxidant, anti-inflammatory and cytotoxic activity, attributes that were lost when seeds were added into the biscuits. These findings highlight the potential health benefits of these ingredients, particularly when incorporated in new wheat-based formulations.

The Mechanism of Antimicrobial Activity of Conjugated Bile Acids against Lactic Acid Bacilli

The mechanism underlying antimicrobial activity of conjugated bile acids against strains of lactic acid bacilli is not well understood. The purpose of this study was to investigate two typical conjugated bile acids (glycochenodeoxycholic acid and taurochenodeoxycholic acid) for their mechanisms of antimicrobial activity against four strains of different species of lactic acid bacilli at the physiological pH of the small intestine of humans. The bacterial cell membrane integrity, transmembrane potential, and transmembrane pH gradient were examined using the fluorescence probes SYTO 9 plus propidium iodide, 3,3'-dipropylthiadicarbocyanine iodide, and 5(6)-carboxyfluorescein diacetate N-succinimidyl ester, respectively. The intracellular ATP levels were measured by the firefly luciferase-based bioluminescence method. It was found that the antimicrobial activity of conjugated bile acids against the strains of lactic acid bacilli is strain-specific, and glycochenodeoxycholic acid showed significantly greater antimicrobial activity than taurochenodeoxycholic acid against the strains of lactic acid bacilli. The conjugated bile acids inhibited the growth of strains of lactic acid bacilli by disrupting membrane integrity, dissipating transmembrane potential, reducing the transmembrane pH gradient, and depleting intracellular ATP. In conclusion, the antimicrobial activity of conjugated bile acids against lactic acid bacilli is a multifactorial phenomenon. This study will provide valuable information for developing strategies to improve the ability of lactic acid bacilli to tolerate bile in vivo.

Plant Antimicrobials for Food Quality and Safety: Recent Views and Future Challenges

The increasing demand for natural, safe, and sustainable food preservation methods drove research towards the use of plant antimicrobials as an alternative to synthetic preservatives. This review article comprehensively discussed the potential applications of plant extracts, essential oils, and their compounds as antimicrobial agents in the food industry. The antimicrobial properties of several plant-derived substances against foodborne pathogens and spoilage microorganisms, along with their modes of action, factors affecting their efficacy, and potential negative sensory impacts, were presented. The review highlighted the synergistic or additive effects displayed by combinations of plant antimicrobials, as well as the successful integration of plant extracts with food technologies ensuring an improved hurdle effect, which can enhance food safety and shelf life. The review likewise emphasized the need for further research in fields such as mode of action, optimized formulations, sensory properties, safety assessment, regulatory aspects, eco-friendly production methods, and consumer education. By addressing these gaps, plant antimicrobials can pave the way for more effective, safe, and sustainable food preservation strategies in the future.