Browsing by Author "Jemai, Eya"
Now showing 1 - 1 of 1
Results Per Page
Sort Options
- Evaluation of LED photostimulation in the fermentation process of table olives and its impact on physico- chemical and microbiological parametersPublication . Jemai, Eya; Martins, Maria de Fátima Tomé; Crugeira, Pedro; Charfi, IchrakThe consumption of fermented foods has increased in recent years due to their potential health benefits. Table olives are a fermented vegetable product, obtained from the fruits of the olive tree (Olea europaea L.), and are considered an integral part of the Mediterranean diet. Recognized for their sensory, chemical, and nutritional characteristics, they have an autochthonous microflora of yeasts and lactic acid bacteria (LAB), considered a source of probiotics. Among the various methods of obtaining table olives, natural fermentation stands out. Carried out due to the action of microorganisms present in the fruits, it is an artisanal, spontaneous, and very slow process, requiring several months to remove the bitterness of the olives and obtain a quality product. This process depends on several factors, essentially the interactions resulting from the consortium of microorganisms inhabiting this environment. In the last decade, table olive producers have been improving the process by introducing some practices, that promote microbial activity, but the time required to obtain edible olives is still very long. Photostimulation with LED light is a practice that has been explored in several areas, including food processing. Light acts as a promoter of the growth of microorganisms, interfering with bioprocesses. In this sense, this study evaluated the effect of LED photostimulation on the natural fermentation of Negrinha de Freixo black olives, focusing on physicochemical, microbiological, and sensory changes. The fermentation process was monitored under red LED light irradiation (630 ± 10 nm) to assess its impact on pH, titratable acidity, salt content, total phenolic compounds, texture, color, and microbial growth in both olives and brine. Results revealed that LED irradiation significantly influenced the fermentation dynamics, promoting higher microbial activity, particularly in yeasts and lactic acid bacteria (LAB), which accelerated the acidification process and improved microbial counts compared to non-irradiated samples. The irradiated olives retained higher hardness and cohesiveness, indicating better structural integrity. In terms of color, there was an increased lightness, redness, and chroma in irradiated olives, enhancing the visual appeal of the final product. The total phenolic content in irradiated olive samples decreased, suggesting that LED light may help reduce bitterness. Sensory analysis indicated that irradiated olives had improved taste attributes, such as enhanced saltiness and reduced bitterness, along with fewer fermentation defects. These findings suggest that LED photostimulation can optimize the natural fermentation process by enhancing microbial growth, preserving texture, and improving sensory qualities, potentially offering a sustainable approach to reducing fermentation time and enhancing the quality of table olives. The study supports the application of LED light as a promising strategy in the table olive industry, with implications for improving the efficiency and quality of the traditional fermentation process.