Search Results (115)

Amid the accelerating spread of antibiotic resistance, medicinal and aromatic plants stand out as powerful natural reservoirs of bioactive compounds, offering innovative prospects for next-generation antimicrobial therapies. To explore its therapeutic potential, this study evaluated the antimicrobial and antioxidant activities of Matricaria pubescens from Southeastern Morocco, supported by a thorough chemical profiling of its essential oils. The oils were obtained by steam distillation and analyzed using gas chromatography–mass spectrometry (GC–MS). The results revealed two distinct chemotypes, with isochrysanthemic ethyl ester (32.7%) as the dominant compound in chemotype EO1 and α-ocimene (19.62%) as the major constituent in chemotype EO2. Antioxidant activities were assessed using DPPH, ABTS, and reducing power assays, while antimicrobial activities were evaluated against bacteria, fungi, and yeasts using both disc diffusion and broth microdilution methods. Both oils exhibited notable antioxidant activities. Significant antimicrobial effects were observed, with Bacillus subtilis, Escherichia coli, and Staphylococcus aureus being the most sensitive strains, whereas Pseudomonas aeruginosa exhibited the highest resistance among all tested microorganisms, with the lowest MIC recorded for B. subtilis (0.612 mg/mL). These findings emphasize that M. pubescens could serve as a valuable source of biologically active compounds, particularly in the development of agents to combat microbial resistance, and further support its potential applications in pharmaceutical, cosmetic, and food industries. Full article

Date palm (Phoenix dactylifera L.) by-products from bioethanol production represent an underutilized resource rich in bioactive molecules. This study aims to their valorization through characterization of polysaccharides and phenolic compounds from the Medjool variety, both before and after yeast fermentation for bioethanol production. Three sequential types of by-products were analyzed—Ext1 (post hot-extraction), Ext2 (post fermentation), and Ext3 (post distillation)—and compared with Dat-Me. High Performance Liquid Chromatograp-Diode Array Detector-Mass Spectrometry (HPLC-DAD-MS) analysis allowed identifying 22 phenolic compounds, primarily cinnamic acid derivatives and glycosylated flavones such as luteolin and chrysoeriol. Fermentation increased total phenolic content from dry weight, while leading to an improved polysaccharide recovery (i.e., from 14.2% to 42.1% dry weight). Two polysaccharide fractions (F1 and F2) were isolated and characterized by ¹H-NMR and Dynamic Light Scattering (DLS). F1 is a pectic polysaccharide, with a galacturonic acid content ranging from 24.2% (Ext3) to 52.2% (Dat-Me), a degree of methylation (DM) between 34.4 and 50.6%, and a degree of acetylation (DA) of 23.6–42.2%. F2 consists of a non-pectic polysaccharide, characterized by a low galacturonic acid content (5.6–6.8%) and a DM of 12.6–47.1%, but it is highly acetylated, with a DA ranging from 90.1 to 93.3%. DLS analysis confirmed fermentation-induced depolymerization, with molecular weights ranging from 6.6 × 10⁴ to 8.5 × 10⁵ KDa for both the fractions. Overall, Medjool date by-products obtained after bioethanol production represent a sustainable source of high-value phenolic antioxidants and polysaccharides with different structures suitable for future applications in food, pharmaceutical, and cosmetic formulations. Full article

In an effort to evaluate the performance of a 5-gallon pot still in separating yeast-derived congeners during the distillation of a grain-based distiller’s beer, the distillates of a fermented mash of cracked corn, malted barley, and wheat were characterized using ¹H NMR spectroscopy and GC-MS. A quantitative comparison using these two techniques is uncommon. Results revealed significant variation in congener concentrations across runs, with a notable discrepancy in the third run possibly due to bacterial contamination, as indicated by high 1-propanol levels. Key congeners, such as acetaldehyde, ethyl acetate, furfural, phenylethanol, and 1,1-diethoxyethane, showed expected distillation behavior across ten fractions, based on their respective boiling points. However, methanol and 1-propanol showed a fairly flat concentration profile across all ten fractions, while those for ethyl octanoate and ethyl hexanoate decreased rapidly and were undetected at fraction 5. White dog (unaged whiskey) fractions from column and combination stills were also analyzed, and the results demonstrate that the small 5-gallon still separates congeners as well as these stills. Finally, a comparison of congener concentrations demonstrates that NMR and GC-MS do not yield identical concentrations of congeners, despite exhibiting similar trends in congener concentrations in the fractions from the still, with GC-MS suggesting higher levels. Full article

The effect of conditions of rye cultivation (conventional and organic) and method of mash preparation and fermentation, as well as supportive enzyme and yeast strains on the alcoholic fermentation efficiency and chemical composition of the obtained distillates was assessed. The conditions of rye cultivation did not affect the chemical composition of the tested rye grain; however the differences in the fermentation efficiency were observed. The supplementation of mashes from both conventional and organic rye grain with protease had a positive effect on ethanol biosynthesis. The rye distillates contained low concentrations of acetaldehyde (from 22.25 to 34.07 mg/L of 100% v/v alcohol and met the recommendations for agricultural distillates (<100 mg acetaldehyde/L of 100% v/v alcohol) in Polish distilleries. The samples obtained from both conventional and organic rye grain, pretreated by the thermal-pressure method, were found to contain higher concentrations of methanol than those obtained by the pressureless method of starch liberation. The concentrations of methanol in all distillates remained below the limit specified in EU Regulation 2019/787 for ethyl alcohol of agricultural origin (i.e., rectified spirit) (≤30 g/hL of 100% v/v alcohol). The distillates from organic rye grain subjected to pressureless pretreatment contained significantly lower concentrations of 2-methylbutanol and 3-methylbutanol than analogous distillates from conventional rye grain. The digestion of mashes with a protease preparation has been shown to increase the concentrations of 3-methyl-butyl acetate and 2-methyl-butyl acetate in distillates, irrespective of the rye grain type, the processing method, and the yeast strain employed for fermentation. Full article

The development of plant-based synbiotic beverages is gaining increasing attention as consumers seek sustainable, functional alternatives to dairy products. This preliminary study investigated the fortification of tibicos (water kefir) with lemon catnip (Nepeta cataria var. citriodora) hydrolate, an aromatic distillation byproduct rich in bioactive terpenoids. After 72 h-fermentation of tibicos, physicochemical, microbiological, health-promoting and sensory parameters were evaluated. Both control and fortified beverages exhibited typical fermentation kinetics, including a decrease in pH, reduction of soluble solids, and accumulation of organic acids. Lactic acid bacteria count remained stable, while yeast proliferation was slightly reduced in the hydrolate-fortified sample, consistent with the known yeast-sensitive nature of certain hydrolate-derived terpenoids. Importantly, hydrolate fortification significantly enhanced antioxidant capacity (DPPH: +34%; ABTS: +39%; RP: +38%). Enzyme-inhibitory activities also increased significantly in the hydrolate-fortified samples (α-Amylase and α-Glucosidase inhibition rates increased by 9% and 11%, respectively). ACE inhibition similarly increased from 32% to 44%, indicating an enhanced antihypertensive potential. HMG-CoA reductase inhibition increased from 31% to 42%, showing improved hypolipidemic activity. Sensory evaluation indicated improved sensory acceptability, imparting citrus–floral notes that balanced the acidic profile of tibicos. These findings highlight the potential of valorizing lemon catnip hydrolate as a functional fortifier in non-dairy synbiotic beverages. Full article

Spirit drink, known in Central and Eastern Europe as ‘okowita’ (its official designation is ‘spirit’), is obtained by distilling fermented plant raw materials. Unlike vodka, which is produced from highly purified ethyl alcohol of agricultural origin, ‘okowita’ is characterised by the preservation of the natural aromatic and flavour compounds originating from the raw material and produced during the process of alcoholic fermentation. The study aimed to assess the impact of production technology on the quality of potato spirits. The effects of the methods used for the pretreatment of raw material, starch hydrolysis and fermentation, and yeast strains were examined in relation to the fermentation efficiency and the chemical composition of the distillates. The yeast strains were the key factor determining fermentation efficiency. The SafSpirit and Pinnacle yeast strains provided the highest fermentation yields (85.0–97.7% of the theoretical), while the Ethanol Red strain provided the lowest yield (<83%). No advantage of separate hydrolysis and fermentation (SHF) over simultaneous saccharification and fermentation (SSF) was observed. A characteristic feature of potato distillates was their high isobutyl alcohol content, ranging from 557 to 1437 mg/L of 100% v/v alcohol, i.e., more than twice that of 3-methyl-1-butanol. Methanol concentrations remained below the limit specified in EU Regulation 2024/1143 (≤1000 g/hL of 100% v/v alcohol). The results are promising in terms of the potential for the production of craft potato spirit drinks. Full article

There has been a recent shift in the global wine market towards reduced-alcohol wines. Muscadine grapes (Vitis rotundifolia) have become a popular choice in many emerging markets; however, their suitability in reduced-alcohol wine production has not been extensively tested. In this study, methods to reduce ethanol in muscadine wine were compared to determine differences in chemical and sensory attributes and consumer preference. The methods evaluated included full fermentation time with Saccharomyces cerevisiae (control), reduced fermentation time with Saccharomyces cerevisiae (stopped fermentation), fermentation with Saccharomycodes ludwigii yeast (instead of Saccharomyces cerevisiae), and vacuum distillation. The control and distilled wines were fermented for 121 h, Saccharomycodes ludwigii for 45 h, and the stopped fermentation wine for 3 h. Yeast and sugar levels were monitored throughout the fermentation processes using brix measurements and yeast counts. After the fermentation, the color, pH, volatiles, and titratable acidity (TA) were measured. The results showed that Saccharomycodes ludwigii fermented more slowly than Saccharomyces cerevisiae, and that both the stopped fermentation and Saccharomycodes ludwigii wines had lower titratable acidity with a more intense color. The total concentration of volatile compounds for the Saccharomycodes ludwigii wine and the stopped wine were lower than for the distilled and control wines. A consumer panel (n = 92) judged the wine samples on chemical qualities and overall preference. The distilled wine was perceived as more alcoholic compared to the other reduced-alcohol wines. The results showed that the stopped fermentation and Saccharomycodes ludwigii wines were preferred by consumers over the control and vacuum-distilled wines. Full article

Wine lees is a semi-solid suspension rich in yeast cells, representing a winemaking by-product that is rarely valorized after distillation. This study focuses on the exploitation of yeast-containing vinasse resulting after wine lees distillation by proposing optimized thermal extractions that can be potentially integrated with the current wine lees distillation workflow. Vinasse with different solids concentrations (10, 30, 50%) were treated at different temperatures (104, 108, 112 °C) and durations (20, 40, 60 min) using a pressure cooker device. The release of proteins, polysaccharides, and oligosaccharides from these pressure-assisted lab extractions were compared with that in untreated vinasse and vinasse treated with a previously proposed autoclave method. The resulting extraction appears to be generally preferable to the autoclave, which would require higher costs for energy and equipment. The obtained extraction process significantly enhanced the recovery of total proteins, oligosaccharides, and medium- to low-molecular-weight polysaccharides. Conversely, all heat treatments reduced the extraction of high-molecular-weight polysaccharides, indicating that these compounds should be directly extracted from untreated vinasse. These outcomes, along with the study of samples’ viscosity, density, and specific heat, allowed us to propose an integrated extraction plant set up that includes a crossflow filter and an industrial cooker. This set up aims to maximize the extraction of each valuable fraction, thereby better exploiting vinasse following a biorefinery approach. Full article

This study explores the production of anhydrous ethanol from discarded fruits, aiming to determine optimal fermentation conditions and evaluate the feasibility of a green separation technology. Fermentation experiments were performed using juices from Psidium guajava (S1), Carica paapaya (S2), and mucilage residues of Coffea arabica (S3). All fermentations were carried out at a pH of 4.5 for 7 days in 1 L bioreactors. A full 2² factorial design was applied to evaluate the effects of two variables: yeast type (commercial Saccharomyces cerevisiae [CY] vs. native yeast [NY]) and temperature (21 °C vs. 30 °C). Higher ethanol concentrations were achieved with CY at 30 °C, yielding 6.79% ethanol for S3. A multi-criteria matrix prioritized coffee residues due to their high ethanol yield, biomass availability, and economic viability. The ethanol was dehydrated using a packed-bed bioadsorption system with crushed corn, which increased purity from 6.7% v/v to 98.9% v/v in two stages, while avoiding azeotropic limitations. Energy analysis revealed low specific consumption (3.68 MJ/kg), outperforming conventional distillation. The results of this study, obtained at operating temperatures of 30 °C and 21 °C, a pH of 4.5, and an operating time of 7 days in a 1L bioreactor, demonstrate ethanol concentrations of 6.79%, confirming the technical feasibility of using agricultural waste as a raw material and validating the efficiency of a bioadsorption-based dehydration system. These findings address the current gap in integrating green ethanol separation with low-cost agricultural residues and highlight a sustainable alternative for decentralized bioethanol production. Full article

This study developed a solid-state fermentation system based on Trichoderma harzianum, which significantly enhanced the nutritional value of distiller’s grain (DG) feed through a multi-stage synergistic treatment process. During the cellulase production phase, rice husk was used as an auxiliary material, and specific degradation of DGs was effectively enhanced. Through optimization using response surface methodology, the optimal enzyme production conditions were determined. The filter paper enzyme activity reached a peak of 1.45 U/gds (enzyme activity per gram of dry substrate) when the moisture content was 53%, the fermentation time was 3 days, and the Tween-80 dosage was 0.015 mL/g (dry weight basis). Under these conditions, the crude enzyme solution was used to hydrolyze DGs. Compared to original DGs, the content of reducing sugars increased by 10.75%. In the stage of protein production, segmented hydrolysis fermentation (SHF) and simultaneous saccharification fermentation (SSF) processes were employed using yeast. The results showed that SSF pathway showed better performance, and the true protein content reached 15.16% after 11 days, an increase of 41.5% compared to the control. Finally, through secondary fermentation regulated by Lactobacillus fermentum, the flavor of the feed was significantly improved. This study innovatively integrated bio-enzymatic hydrolysis and multi-strain synergistic fermentation technologies, providing a novel strategy for the efficient and sustainable production of protein feed based on DGs. Full article

This study investigates the effect of ultrasonic treatment on the fermentation of molasses wort with a density range of 18–24 °Blg, using two high-performance Saccharomyces cerevisiae yeast strains: Thermosacc Dry and Ethanol Red. The primary objective was to determine if ultrasound could accelerate fermentation and increase ethanol yield. The research showed that ultrasonic treatment at 24 kHz significantly increased fermentation dynamics and ethanol yield by 5 to 20%, depending on the yeast strain and wort density. Higher wort densities (22–24 °Blg) showed more pronounced positive effects. Ultrasound treatment caused visible indentations in the yeast cell walls and promoted cell aggregation. In addition, the study investigated the influence of different ultrasound amplitudes on fermentation efficiency and showed that higher amplitudes further improved ethanol production in 22–24 °Blg worts. These results suggest that ultrasound can improve the efficiency and profitability of ethanol production, highlighting the potential for further research to optimise industrial fermentation processes. The application of ultrasound in biotechnology, particularly in fuel ethanol production, could lead to significant economic benefits on a global scale. Full article

The production of fruit brandies is based on distilling fermented fruit juices. Distillation equipment is usually made of copper. In traditional manufacturing, it consists of a boiler (batch) distiller, a boiler (pot), a steam pipe, and a condenser, all of which are made of pure copper. This study determined the corrosion parameters for copper (Cu) and Cu72Zn28 (in wt%) alloy in fermented apricot juice at room temperature. The fermentation process examined in this research utilized natural strains of yeast and bacteria, supplemented by active dry yeast Saccharomyces cerevisiae strains. This research used the following methods: open circuit potential (OCP), linear polarization resistance (LPR), and Tafel extrapolation to identify corrosion parameters. Cu had a 3.8-times-lower value of corrosion current density than brass, and both were within the range of 1–10 μA·cm⁻², with an excellent agreement between LRP and Tafel. This study proved that Cu is an adequate material for the distillation of fruit brandies from a corrosion perspective. Despite this, there are occasional reports of corrosion damage from the field. Significant corrosion impacts can arise, as evidenced by laboratory tests discussed in this paper. In the absence of a highly corrosive environment, this study indicates that, to some extent, microbiologically influenced corrosion (MIC) can influence the degradation of the equipment material. Full article

Bioethanol is a renewable, environmentally-friendly biofuel conventionally produced through the alcoholic fermentation of sugary or starch-rich substrates by microorganisms, commonly Yeast Saccharomyces cerevisiae. Intermediates of industrial wheat flour wet milling processing to starch, such as A-starch and B-starch milk, are cost-effective, abundant, and non-seasonal feedstocks for bioethanol production. This study evaluates the bioethanol production from wheat A-starch and B-starch milk and mixtures of these two substrates in different ratios (1:3, 1:1, and 3:1) using two cold hydrolysis procedures at 65 °C: (i) simultaneous liquefaction and saccharification (SLS) followed by fermentation, and (ii) liquefaction by alpha-amylase followed by simultaneous saccharification and fermentation (SSF). The results demonstrated that SSF and SLS are equally efficient procedures for reaching a high ethanol yield of 53 g per 100 g of starch and 93% of starch conversion to ethanol for all investigated substrates. Lower levels of non-starch components in A-starch milk, which typically contribute to volatile by-product formation, allowed clear distillate profiles in terms of and lower content of aldehydes, methanol, and volatile acidity, enhancing ethanol distillate purity compared to B-starch milk. Mixing high-quality A-starch milk with low-cost B-starch milk enables higher ethanol yield, improved distillate quality, and energy savings for efficient industrial-scale applications. Full article

The probiotic properties of the yeast Saccharomyces boulardii are fairly well recognised, and research into the use of this strain in fermentation processes has been ongoing for several years. In this article, we have described the research results to evaluate the distillery potential of S. boulardii yeast. Compared to Ethanol Red and Thermosacc Dry yeast, the probiotic strain formed slightly different amounts of volatile compounds and fermented the available sugars less vigorously. The final ethanol concentration formed by the probiotic yeast was close to that observed for the distillery strains. Rye distillates with an alcohol content of 40% (v/v) obtained with S. boulardii yeast, according to the sensory panel, were distinguished by their delicately composed flavour and were rated better than distillates after fermentation by distillery yeast. The results are promising for the possibility of production of niche distillates using probiotic yeast. Full article

The objective of this study was to investigate the impact of co-fermentation of Italia and Negra Criolla grape musts using non-Saccharomyces yeast strains (NSYSs) isolated from both grape varieties, on the major volatile compounds and sensory characteristics of Piscos (distilled spirits). Native NSYSs previously isolated from Italia (Pichia terricola, Metschnikowia pulcherrima, and Naganishia vaughanmartiniae) and Negra Criolla (Vishniacozyma carnescens, Vishniacozyma heimaeyensis, and Aureobasidium pullulans) grapes’ skins were inoculated at the beginning of grape must fermentation. A centroid simplex design was applied in order to obtain 10 representative yeast blends for use as mono- (n = 3), bi- (n = 3), and ternary (n = 4) inoculations. Additionally, a control sample without inoculum was also set up. For each yeast blend, the volatile composition and sensory characteristics of Piscos were evaluated. Results showed that mono-inoculation using specific NSYSs, such as P. terricola, M. pulcherrima, and N. vaughanmartiniae, led to a notable predominance of some terpenes such as α-terpineol, citronerol, and geraniol in Pisco from Italia grapes compared to the control Pisco. Conversely, in Pisco from Negra Criolla grapes, where V. carnescens, V. heimaeyensis, and A. pullulans were used in a similar mono-inoculation process, a higher presence of phenylethyl alcohol and 2-phenylethyl acetate compared to the control was observed. The sensory analysis revealed that citrus, floral, alcohol, and syrup descriptors had a higher intensity in mono-inoculated Pisco Italia, whereas spice, herbaceous, and cooked vegetable descriptors had the highest intensity in Negra Criolla Piscos produced with ternary NSYS inoculum inoculations. This study demonstrates that the use of native non-Saccharomyces yeast strains in the co-fermentation of grape musts can significantly influence the volatile profile and sensory characteristics of Pisco. These findings will allow us to establish new inoculation strategies to impact the overall sensory and aromatic profile of the Piscos produced with different grape varieties. Full article