Étude du potentiel fermentaire de la pomme libanaise et impact des procédés émergents sur la fermentation du jus en vue de l’élaboration du cidre

This work concerns the valorization of Lebanese apples by evaluating its potential to produce cider, specifically the fermentation stage of this process. For this purpose, the chemical composition of the Lebanese apples “Ace spur” was analyzed in comparison with a cider apple “Kermerrien” used industrially in France for cider production. The Lebanese apple variety “Ace spur” appears to be suitable for cider making. In addition, a strain responsible for the spontaneous fermentation of this variety of apples was isolated and identified. Its fermenting potential in these two varieties of apples has been studied. The isolated yeast Hanseniaspora sp. can ferment apple juices up to 4% ethanol (v,v). This study will provide first-time data on the chemical composition of the Lebanese apple, on the potential of a strain present during its fermentation. Also, this work evaluates the impact of emerging technologies like pulsed electric field and ultrasound on yeast fermentative activity. A continuous apple juice treatment that can be scaled from laboratory to industrial scale is proposed. The various results obtained showed the chemical potential of the Lebanese variety “Ace spur” in cider production. The application of those emerging technologies can accelerate growth kinetics while reducing ethanol contents.Ce travail de thèse concerne la valorisation des pommes libanaises en évaluant leur potentiel fermentaire en vue de l’élaboration du cidre, spécifiquement l’étape de la fermentation de ce processus. Pour cette fin, l’analyse de la composition chimique des pommes libanaises « Ace spur » a été effectué en comparaison avec une pomme à cidre « Kermerrien » utilisée industriellement en France pour la production du cidre. La variété de pomme libanaise « Ace spur » semble être convenable pour l’élaboration de cidre. De plus, une souche responsable de la fermentation spontanée de cette variété de pommes a été isolée et identifiée. Son potentiel fermentaire dans ces deux variétés de pommes a été par la suite étudié. La levure Hanseniaspora sp. isolée permet la fermentation des jus de pommes jusqu’à 4% (v,v) d’éthanol. Cette étude fournira pour la première fois des données sur la composition chimique de la pomme libanaise, sur une souche présente lors de sa fermentation, ainsi que sur son potentiel fermentaire. Également, les travaux de la thèse consistent à évaluer l’impact des procédés émergents : champs électriques pulsés et ultrasons sur la fermentation. Ces travaux visent à démontrer le potentiel d’implémentation de ces procédés industriellement. Nous proposerons une approche de traitement du jus de pommes en continu qui pourra être transposée de l’échelle laboratoire à l’échelle industrielle. L’application des technologies émergentes (champs électriques pulsés et ultrasons) induit une accélération des cinétiques fermentaires et une réduction du taux d’éthanol

Study of the fermentative potential of lebanese apples and impact on emerging processes on the fermentation for the cider production

Ce travail de thèse concerne la valorisation des pommes libanaises en évaluant leur potentiel fermentaire en vue de l’élaboration du cidre, spécifiquement l’étape de la fermentation de ce processus. Pour cette fin, l’analyse de la composition chimique des pommes libanaises « Ace spur » a été effectué en comparaison avec une pomme à cidre « Kermerrien » utilisée industriellement en France pour la production du cidre. La variété de pomme libanaise « Ace spur » semble être convenable pour l’élaboration de cidre. De plus, une souche responsable de la fermentation spontanée de cette variété de pommes a été isolée et identifiée. Son potentiel fermentaire dans ces deux variétés de pommes a été par la suite étudié. La levure Hanseniaspora sp. isolée permet la fermentation des jus de pommes jusqu’à 4% (v,v) d’éthanol. Cette étude fournira pour la première fois des données sur la composition chimique de la pomme libanaise, sur une souche présente lors de sa fermentation, ainsi que sur son potentiel fermentaire. Également, les travaux de la thèse consistent à évaluer l’impact des procédés émergents : champs électriques pulsés et ultrasons sur la fermentation. Ces travaux visent à démontrer le potentiel d’implémentation de ces procédés industriellement. Nous proposerons une approche de traitement du jus de pommes en continu qui pourra être transposée de l’échelle laboratoire à l’échelle industrielle. L’application des technologies émergentes (champs électriques pulsés et ultrasons) induit une accélération des cinétiques fermentaires et une réduction du taux d’éthanol.This work concerns the valorization of Lebanese apples by evaluating its potential to produce cider, specifically the fermentation stage of this process. For this purpose, the chemical composition of the Lebanese apples “Ace spur” was analyzed in comparison with a cider apple “Kermerrien” used industrially in France for cider production. The Lebanese apple variety “Ace spur” appears to be suitable for cider making. In addition, a strain responsible for the spontaneous fermentation of this variety of apples was isolated and identified. Its fermenting potential in these two varieties of apples has been studied. The isolated yeast Hanseniaspora sp. can ferment apple juices up to 4% ethanol (v,v). This study will provide first-time data on the chemical composition of the Lebanese apple, on the potential of a strain present during its fermentation. Also, this work evaluates the impact of emerging technologies like pulsed electric field and ultrasound on yeast fermentative activity. A continuous apple juice treatment that can be scaled from laboratory to industrial scale is proposed. The various results obtained showed the chemical potential of the Lebanese variety “Ace spur” in cider production. The application of those emerging technologies can accelerate growth kinetics while reducing ethanol contents

Impact of the Physicochemical Composition and Microbial Diversity in Apple Juice Fermentation Process: A Review

Fermented apple beverages are produced all over the world with diverse characteristics associated with each country. Despite the diversifications, cider producers are confronted with similar issues and risks. The nature of the raw material, also known as the fermentation medium, plays a key role in fermentation. A well-defined composition of apples is, therefore, required to produce cider with good quality. In addition, ferment and its metabolism are important factors in the fermentation process. The producers of cider and other alcoholic beverages are looking in general for novel yeast strains or for the use of native strains to produce “authentic” and diversified beverages that are distinct from each other, and that attract more and more consumers. Research articles on cider production are infrequent compared to wine production, especially on the impact of the chemical composition and microbial diversity of apples on fermentation. Even though the processing of fermented beverages is close in terms of microbial interactions and production, the study of the specific properties of apples and the production challenges of cider production is advantageous and meaningful for cider producers. This review summarizes the current knowledge on apple composition and the impact of the must composition on fermentation and yeast growth. In addition, the microbial diversity of cider, activities, and its influence on fermentation are reviewed

Suitability of the Lebanese “Ace Spur” Apple Variety for Cider Production Using Hanseniaspora sp. Yeast

In the present research work, the physicochemical and fermentative properties of the “Ace spur” apple variety, obtained from a Lebanese farm, and the “Kermerrien” variety, obtained from a French cider industry, were investigated. The pomological properties were first determined for both varieties showing significant differences in the shapes and sizes. Sugar content, titratable acidity, soluble solids, and pH values were then determined. The potential of the “Ace spur” apple juice was then evaluated using the yeast strain Hanseniaspora sp., a major yeast found during the spontaneous fermentation of apples. “Ace spur” apples contained more sugars while the “Kermerrien” cultivar had a highest malic acid and polyphenol concentrations. After 100 h of fermentation, the ethanol percentage (v/v) was around 4% in both ciders. Results obtained in this work revealed the chemical potential of the Lebanese apple juice to produce cider

Special Issue on “Processing and Conversion of Oil and Gas: Modeling, Control, Simulation and Optimization”

Petroleum is considered the black gold of the earth, but this treasure cannot be utilized without the usage of innovative and advanced technologies for its recovery and conversion [...

Pulsed electric field-assisted fermentation of Hanseniaspora sp. yeast isolated from Lebanese apples

International audienceHanseniaspora sp. yeast was stimulated using pulsed electric field (PEF) during the different fermentation phases. The impact of PEF parameters on the growth rate and substrate consumption was studied. The PEF intensities chosen for this study were mainly in the range of 72–285 V cm−1. A PEF treatment chamber was designed for this study with a ratio of 1:50 between the volume of the fermenter and the volume of the chamber. It allows the recycling of the culture medium using a peristaltic pump, and the yeast treatment by PEF during the fermentation. The continuous circulation of the medium allows avoiding the increase of the temperature inside the fermenter, the cell aggregation, as well as the agitation and the scale-up issues that are associated with the PEF treatment of the entire volume in batch mode. The maximal yeast growth rate was obtained using an electric field strength of 285 V cm−1 applied during both Lag and early exponential phase, and Log phase. This observation was accompanied by a faster consumption of glucose in the medium during the fermentation. Besides, the sensitivity of Hanseniaspora sp. yeast to PEF treatment was more pronounced during the Lag and early exponential phase than the Log phase. The results obtained exposed the great benefit of stimulating Hanseniaspora sp. yeast using moderate PEF as it reduces the fermentation time along with increasing the biomass concentration

Ultrasound-assisted fermentation for cider production from Lebanese apples

International audienceThe present work studies the impact of low-intensity ultrasound (US) on Hanseniaspora sp. yeast fermentations. The effect of pulse duration and growth phase on US application was first evaluated using a synthetic medium. The optimal conditions were then applied to apple juice US-assisted fermentation. An US treatment chamber was first designed to allow the recycling of the culture medium. The optimal US pulse duration on the yeast growth rate was of 0.5 s followed by 6 s rest period, and during 6 h of both Lag and Log phases. These US parameters led to a faster consumption of glucose in the medium during the fermentation, compared to the untreated culture. The impact of US was also depending on the growth phase, showing higher sensitivity of the yeast to US during the Lag phase rather than the Log phase. US-assisted fermentation of apple juice showed a significant increase in biomass growth and glucose consumption, along with a significant decrease in the ethanol yield. The fastest growth kinetic (by 52%), and the highest ethanol reduction (by 0.55% (v, v)) were obtained for the treatment during the first 12 h of fermentation, thereby, the stationary phase was reached faster, and the maximum biomass growth rate was 10 folds higher compared to the untreated culture. The results obtained in this study demonstrated the promising efficiency of US-assisted fermentation in stimulating the biomass growth and reducing the ethanol content in alcoholic beverages

Control of the sugar/ethanol conversion rate during moderate pulsed electric field-assisted fermentation of a Hanseniaspora sp. strain to produce low-alcohol cider

International audienceThe effect of moderate pulsed electric fields (PEF) on Hanseniaspora sp. fermentations in apple juice was examined. The treatments were applied prior to or during the fermentation using a field strength of 285 V/cm. A significant increase (p < 0.05) in the biomass growth was observed during all the treatments along with a significant decrease (p < 0.05) in the ethanol yield. The optimal impact of PEF on ethanol reduction by 1.6% (v, v) was obtained during the treatment of the pre-culture for 6 h. The greatest rate was observed for the treatment during the first 12 h of the fermentation. During this fermentation performed at 28 °C under agitation at 250 rpm, the time to reach the stationary phase was reduced by 10 h, and the maximum biomass growth rate was ten-fold higher than that of the control. In addition, the sensitivity of Hanseniaspora sp. yeast to PEF treatment was more pronounced during the lag phase rather than the log phase in term of shortening the fermentation time, and reducing the ethanol content. The results obtained here demonstrated the promising efficiency of stimulated yeast by PEF in reducing the ethanol content in fermented alcoholic beverages

Characterization of Antagonist Potential of Selected Compost Bacterial Isolates (CBI) against Plant and Human Pathogens

Several fecal and enteric pathogens are present within the primary organic raw materials that are introduced to compost piles. These pathogens may compete with the existing microbiota and limit their efficiency, yielding only partial decomposition of the final compost. These pathogens also affect the process kinetics and persist in the final compost or may even regrow as a result of the declining effect of indigenous antagonistic micro-organisms. In this work, 11 indigenous bacterial isolates were selected from compost piles that were constructed from different percentages of comingled primary organic raw materials. Enzymatic, biochemical, and genetic characterization profiling of these strains was fulfilled. The top hits supplied by GenBank proved the genetic diversity of these strains, which belonged to 6 different families. This diversity, applied also at enzymatic and biochemical levels, showed the different degradation patterns of amino acids, carbohydrates, hormones, and proteins. CBI2 has been shown to be the most active isolate in the degradation of the different types of hormones and proteins from dairy products but lacks the enzymes needed for the degradation of ammonia into nitrogen. The antagonistic potential of recuperated secondary metabolites proved the total inhibition of all strains against Fusarium oxysporum and no growth limitation against Botrytis cinerea. Only the secondary metabolites of CBI1, CBI5, and CBI9 isolates showed inhibitory activity against Salmonella Typhimurium and Escherichia coli, whereas only those of CBI6 and CBI8 inhibited the growth of Salmonella Typhimurium and Listeria monocytogenes accordingly. From that finding, these strains are considered pioneering, with high potential to ensure both the efficient degradation of organic matter and the elimination of existing pathogens when applied to compost piles