Next Issue
Volume 8, January
Previous Issue
Volume 7, September
 
 

Fermentation, Volume 7, Issue 4 (December 2021) – 122 articles

Cover Story (view full-size image): The aim of this study was to valorize walnut green husk, which is an agro-waste produced during the walnut (Juglans regia L.) harvest. Glucans and pectins are isolated from dry walnut husks by carrying out simple conventional extraction procedures, and then, they are characterized by FT-IR, scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). The results suggest that green husks could be a commercial source of glucans and pectins whose content and morphological and thermal characteristics are influenced by different soil and climate conditions. View this paper
  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Readerexternal link to open them.
Order results
Result details
Section
Select all
Export citation of selected articles as:
Review
Non-Conventional Grape Varieties and Yeast Starters for First and Second Fermentation in Sparkling Wine Production Using the Traditional Method
Fermentation 2021, 7(4), 321; https://doi.org/10.3390/fermentation7040321 - 20 Dec 2021
Cited by 3 | Viewed by 1071
Abstract
Sparkling wine production using the traditional method involves a second fermentation of still wines in bottles, followed by prolonged aging on lees. The key factors affecting the organoleptic profiles of these wines are the grape varieties, the chemical and sensory attributes of the [...] Read more.
Sparkling wine production using the traditional method involves a second fermentation of still wines in bottles, followed by prolonged aging on lees. The key factors affecting the organoleptic profiles of these wines are the grape varieties, the chemical and sensory attributes of the base wines elaborated, the yeast strains used for first and second fermentation, and the winery practices. While Chardonnay and Pinot noir are gold standard grape varieties in sparkling wine production, other valuable grape cultivars are used worldwide to elaborate highly reputable sparkling wines. Fundamental research on the chemical and sensory profiles of innovative sparkling wines produced by the traditional method, using non-conventional grape varieties and novel yeast strains for first and/or second fermentation, is accompanying their market diversification. In this review, we summarize relevant aspects of sparkling wine production using the traditional method and non-conventional grape varieties and yeast starters. Full article
(This article belongs to the Special Issue Control of Wine Fermentation)
Show Figures

Figure 1

Article
The Effect of Incubation Temperature, Substrate and Initial pH Value on Plantaricin Activity and the Relative Transcription of pln Genes of Six Sourdough Derived Lactiplantibacillus plantarum Strains
Fermentation 2021, 7(4), 320; https://doi.org/10.3390/fermentation7040320 - 19 Dec 2021
Viewed by 719
Abstract
The aim of the present study was to assess the effect of sourdough related parameters on the growth and plantaricin activity of six Lactiplantibacillus plantarum strains against a mixture of 5 Listeria monocytogenes strains and to analyze the transcriptomic response of their pln [...] Read more.
The aim of the present study was to assess the effect of sourdough related parameters on the growth and plantaricin activity of six Lactiplantibacillus plantarum strains against a mixture of 5 Listeria monocytogenes strains and to analyze the transcriptomic response of their pln genes. Parameters included 3 substrates (MRS broth, mMRS broth, WFE), 3 temperatures (20, 30, 37 °C), 2 initial pH values (5.0, 6.0), 2 NaCl concentrations (0.0, 1.8%) and 12 time points (ranging from 0 to 33 h). The transcriptomic response of the plantaricin genes to the aforementioned parameters was assessed after 21 h of growth. In general, plantaricin activity was strain dependent with that of Lp. plantarum strains LQC 2422, 2441, 2485 and 2516, harboring four pln genes, namely, pln423 (plαA), plαΒ, plαC and plαD, reaching 2560 AU/mL. However, strains LQC 2320 and 2520, in which 18 pln genes were detected, namely, plNC8a, plNC8b, plNC8c, plnL, plnR, plnJ, plnK, plnE, plnF, plnH, plnS, plnY, plNC8-IF, plNC8-HK, plnD, plnI, plnM and plnG, exhibited plantaricin activity barely reaching 160 AU/mL. Substrate, temperature, initial pH value and strains significantly affected plantaricin activity, while NaCl had only a marginal effect. Similarly, growth substrate and temperature had a more pronounced effect than initial pH value on gene transcription. A strong correlation between the transcription of the genes belonging to the same locus was observed; however, only a weak correlation, if any, was observed between plantaricin activity and the transcription of the genes assessed. Full article
(This article belongs to the Special Issue Innovations in Sourdough Bread Making)
Show Figures

Figure 1

Article
pH-Based Control Strategies for the Nitrification of High-Ammonium Wastewaters
Fermentation 2021, 7(4), 319; https://doi.org/10.3390/fermentation7040319 - 19 Dec 2021
Cited by 1 | Viewed by 797
Abstract
Aquatic nitrogen pollution is one of the most urgent environmental issues requiring prevention and mitigation. Large quantities of high-ammonium wastewaters are generated by several industrial sectors, such as fertilizer and anaerobic-digestion plants. Nitrification of these wastewaters is commonly carried out, either to remove [...] Read more.
Aquatic nitrogen pollution is one of the most urgent environmental issues requiring prevention and mitigation. Large quantities of high-ammonium wastewaters are generated by several industrial sectors, such as fertilizer and anaerobic-digestion plants. Nitrification of these wastewaters is commonly carried out, either to remove nitrogen or produce liquid fertilizers. Standard control methodologies for the efficient nitrification of high-ammonium wastewaters to produce liquid fertilizers have not yet been established and are still within their early stages of development. In this paper, novel pH-based control algorithms are presented that maintain operation at the microbial maximum reaction rate (υmax) in batch and continuous reactors. Complete conversion of ammonium to nitrate was achieved in a batch setup, and a conversion of 93% (±1%) was achieved in a continuously-stirred-tank-reactor. The unparalleled performance and affordability of the control schemes proposed offer a steppingstone to the future of sustainable fertilizer production. Full article
(This article belongs to the Special Issue Recent Trends in Biogenic Gas, Waste and Wastewater Fermentation)
Show Figures

Graphical abstract

Article
Monitoring of Biopolymer Production Process Using Soft Sensors Based on Off-Gas Composition Analysis and Capacitance Measurement
Fermentation 2021, 7(4), 318; https://doi.org/10.3390/fermentation7040318 - 18 Dec 2021
Cited by 1 | Viewed by 719
Abstract
This paper focuses on the design of soft sensors for on-line monitoring of the biotechnological process of biopolymer production, in which biopolymers are accumulated in bacteria as an intracellular energy storage material. The proposed soft sensors for on-line estimation of the biopolymer concentration [...] Read more.
This paper focuses on the design of soft sensors for on-line monitoring of the biotechnological process of biopolymer production, in which biopolymers are accumulated in bacteria as an intracellular energy storage material. The proposed soft sensors for on-line estimation of the biopolymer concentration represent an interesting alternative to the traditional off-line analytical techniques of limited applicability for real-time process control. Due to the complexity of biochemical reactions, which make it difficult to create reasonably complex first-principle mathematical models, a data-driven approach to the design of soft sensors has been chosen in the presented study. Thus, regression methods were used in this design, including multivariate statistical methods (PLS, PCR). This approach enabled the creation of soft sensors using historical process data from fed-batch cultivations of the Pseudomonas putida KT2442 strain used for the production of medium-chain-length polyhydroxyalkanoates (mcl-PHAs). Specifically, data from on-line measurements of off-gas composition analysis and culture medium capacitance were used as input to the soft sensors. The resulting soft sensors allow not only on-line estimation of the biopolymer concentration, but also the concentration of the cell biomass of the production bacterial culture. For most of these soft sensors, the estimation error did not exceed 5% of the measurement range. In addition, soft sensors based on capacitance measurement were able to accurately detect the end of the production phase. This study thus offers an innovative and practically relevant contribution to the field of monitoring of bioprocesses used for the production of medium-chain-length biopolymers. Full article
(This article belongs to the Section Fermentation Process Design)
Show Figures

Figure 1

Article
Aspergillus oryzae Grown on Rice Hulls Used as an Additive for Pretreatment of Starch-Containing Wastewater from the Pulp and Paper Industry
Fermentation 2021, 7(4), 317; https://doi.org/10.3390/fermentation7040317 - 16 Dec 2021
Cited by 1 | Viewed by 746
Abstract
From an industrial point of view, the use of microorganisms as a wastewater bioremediation practice represents a sustainable and economic alternative for conventional treatments. In this work, we investigated the starch bioremediation of paper mill wastewater (PMW) with Aspergillus oryzae. This amylase-producing [...] Read more.
From an industrial point of view, the use of microorganisms as a wastewater bioremediation practice represents a sustainable and economic alternative for conventional treatments. In this work, we investigated the starch bioremediation of paper mill wastewater (PMW) with Aspergillus oryzae. This amylase-producing fungus was tested in submerged fermentation technology (SmF) and solid-state fermentation (SSF) on rice hulls. The tests were conducted to assay the concentration of the reducing sugars on paper mill wastewater. The bioremediation of starch in the wastewater was carried out by A. oryzae, which proved capable of growing in this complex media as well as expressing its amylase activity. Full article
(This article belongs to the Special Issue Food Waste Valorization)
Show Figures

Figure 1

Article
Promotion of the Hypocrellin Yield by a Co-Culture of Shiraia bambusicola (GDMCC 60438) with Arthrinium sp. AF-5 Fungus
Fermentation 2021, 7(4), 316; https://doi.org/10.3390/fermentation7040316 - 16 Dec 2021
Cited by 2 | Viewed by 768
Abstract
Hypocrellin is a natural 3,10-xylene-4,9-anthracene derivative compound that originates from the stroma of Shiraia bambusicola (S. bambusicola) and Hypocrella bambusae with excellent photobiological activities. Submerged fermentation with the mycelia of S. bambusicola is generally regarded as an ideal technology for hypocrellin [...] Read more.
Hypocrellin is a natural 3,10-xylene-4,9-anthracene derivative compound that originates from the stroma of Shiraia bambusicola (S. bambusicola) and Hypocrella bambusae with excellent photobiological activities. Submerged fermentation with the mycelia of S. bambusicola is generally regarded as an ideal technology for hypocrellin production. This study developed a co-cultivation strategy for an obvious promotion of the hypocrellin yield by incubating S. bambusicola (GDMCC 60438) with the endophyte fungus Arthrinium sp. AF-5 isolated from the bamboo tissue. The results indicated that the yield of hypocrellin A (HA) reached a 66.75 mg/g carbon source after an 84-h co-cultivation of the two strains, which was a four-time increase of that by the fermentation only with the S. bambusicola. The microscope observation found that the mycelia of the two strains were intertwined with each other to form the mycelium pellets during the co-cultivation. Moreover, the mycelium pellets of the co-culture showed a contracted and slightly damaged morphology. The addition of H2O2 in the fermentation media could further increase the HA production by 18.31%. Full article
(This article belongs to the Special Issue Mixed Culture Fermentation)
Show Figures

Figure 1

Article
Triacyl Glycerols from Yeast-Catalyzed Batch and Fed-Batch Bioconversion of Hydrolyzed Lignocellulose from Cardoon Stalks
Fermentation 2021, 7(4), 315; https://doi.org/10.3390/fermentation7040315 - 16 Dec 2021
Viewed by 749
Abstract
The lipogenic ability of the yeast Solicoccozyma terricola DBVPG 5870 grown on hydrolyzed lignocellulose obtained from cardoon stalks was evaluated. Data on cell biomass, lipid production, and fatty acid profiles of triacylglycerols obtained in batch and fed-batch experiments were carried out at the [...] Read more.
The lipogenic ability of the yeast Solicoccozyma terricola DBVPG 5870 grown on hydrolyzed lignocellulose obtained from cardoon stalks was evaluated. Data on cell biomass, lipid production, and fatty acid profiles of triacylglycerols obtained in batch and fed-batch experiments were carried out at the laboratory scale in a 5L fermenter, and at two different temperatures (20 and 25 °C) were reported. The higher production of total intracellular lipids (13.81 g/L) was found in the fed-batch experiments carried out at 20 °C. S. terricola exhibited the ability to produce high amounts of triacylglycerol (TAGs) with a characteristic fatty acids profile close to that of palm oil. The TAGs obtained from S. terricola grown on pre-treated lignocellulose could be proposed as a supplementary source of oleochemicals. Indeed, due to the rising prices of fossil fuels and because of the environmental-related issues linked to their employment, the use of TAGs produced by S. terricola grown on lignocellulose could represent a promising option as a supplementary oleochemical, especially for biodiesel production. Full article
(This article belongs to the Special Issue Bioconversion of Lignocellulosic Materials to Value-Added Products)
Show Figures

Figure 1

Review
Recent Developments and Current Status of Commercial Production of Fuel Ethanol
Fermentation 2021, 7(4), 314; https://doi.org/10.3390/fermentation7040314 - 15 Dec 2021
Cited by 6 | Viewed by 1364
Abstract
Ethanol produced from various biobased sources (bioethanol) has been gaining high attention lately due to its potential to cut down net emissions of carbon dioxide while reducing burgeoning world dependence on fossil fuels. Global ethanol production has increased more than six-fold from 18 [...] Read more.
Ethanol produced from various biobased sources (bioethanol) has been gaining high attention lately due to its potential to cut down net emissions of carbon dioxide while reducing burgeoning world dependence on fossil fuels. Global ethanol production has increased more than six-fold from 18 billion liters at the turn of the century to 110 billion liters in 2019, only to fall to 98.6 billion liters in 2020 due to the pandemic. Sugar cane and corn have been used as the major feedstocks for ethanol production. Lignocellulosic biomass has recently been considered as another potential feedstock due to its non-food competing status and its availability in very large quantities. This paper reviews recent developments and current status of commercial production of ethanol across the world with a focus on the technological aspects. The review includes the ethanol production processes used for each type of feedstock, both currently practiced at commercial scale and still under developments, and current production trends in various regions and countries in the world. Full article
(This article belongs to the Special Issue Ethanol and Value-Added Co-products 3.0)
Show Figures

Figure 1

Article
Recycling and Conversion of Yeasts into Organic Nitrogen Sources for Wine Fermentation: Effects on Molecular and Sensory Attributes
Fermentation 2021, 7(4), 313; https://doi.org/10.3390/fermentation7040313 - 14 Dec 2021
Viewed by 851
Abstract
Organic nitrogen plays a significant role in the fermentation performance and production of esters and higher alcohols. This study assessed the use of yeast protein hydrolysate (YPH) as a nitrogen source for grape must fermentation. In this study, we prepared an enzymatic protein [...] Read more.
Organic nitrogen plays a significant role in the fermentation performance and production of esters and higher alcohols. This study assessed the use of yeast protein hydrolysate (YPH) as a nitrogen source for grape must fermentation. In this study, we prepared an enzymatic protein hydrolysate using yeasts recovered from a previous fermentation of wine. Three treatments were performed. DAP supplementation was used as a control, while two YPH treatments were used. Low (LDH) and high degrees of hydrolysis (HDH), 3.5% and 10%, respectively, were chosen. Gas chromatography and principal component analysis indicated a significant positive influence of YPH-supplementations on the production of esters and higher alcohols. Significantly high concentrations of 3-methyl-1-penthanol, isoamyl alcohol, isobutanol, and 2-phenylethanol were observed. Significant odorant activity was obtained for 3-methyl-1-pentanol and ethyl-2-hexenoate. The use of YPH as nitrogen supplementation is justified as a recycling yeasts technique by the increase in volatile compounds. Full article
(This article belongs to the Special Issue Wine Aromas)
Show Figures

Graphical abstract

Article
Bioprocessing of Shrimp Waste Using Novel Industrial By-Products: Effects on Nutrients and Lipophilic Antioxidants
Fermentation 2021, 7(4), 312; https://doi.org/10.3390/fermentation7040312 - 14 Dec 2021
Viewed by 930
Abstract
The production of marine foods is on the rise, and shrimp is one of the most widely consumed. As a result, a considerable amount of shrimp waste is generated, becoming a hazardous problem. Shrimp waste is a rich source of added-value components such [...] Read more.
The production of marine foods is on the rise, and shrimp is one of the most widely consumed. As a result, a considerable amount of shrimp waste is generated, becoming a hazardous problem. Shrimp waste is a rich source of added-value components such as proteins, lipids, chitin, minerals, and carotenoids; however, new bioprocesses are needed to obtain these components. This work aimed to characterize the chemical and nutraceutical constituents from the liquor of shrimp waste recovered during a lactic acid fermentation process using the novel substrate sources whey and molasses. Our results showed that the lyophilized liquor is a rich source of proteins (25.40 ± 0.67%), carbohydrates (38.92 ± 0.19%), minerals (calcium and potassium), saturated fatty acids (palmitic, stearic, myristic and lauric acids), unsaturated fatty acids (oleic acid, linoleic, and palmitoleic acids), and astaxanthin (0.50 ± 0.02 µg astaxanthin/g). Moreover, fermentation is a bioprocess that allowed us to obtain antioxidants such as carotenoids with an antioxidant capacity of 154.43 ± 4.73 µM Trolox equivalent/g evaluated by the ABTS method. Our study showed that liquor from shrimp waste fermentation could be a source of nutraceutical constituents with pharmaceutical applications. However, further studies are needed to separate these added-value components from the liquor matrix. Full article
(This article belongs to the Special Issue Valorization of Waste from Agro-Food, Food and Marine Industry)
Show Figures

Graphical abstract

Article
The Influence of Yeast Strain on Whisky New Make Spirit Aroma
Fermentation 2021, 7(4), 311; https://doi.org/10.3390/fermentation7040311 - 14 Dec 2021
Cited by 1 | Viewed by 1234
Abstract
Flavour in Scotch malt whisky is a key differentiating factor for consumers and producers alike. Yeast (commonly Saccharomyces cerevisiae) metabolites produce a significant amount of this flavour as part of distillery fermentations, as well as ethanol and carbon dioxide. Whilst yeast strains contribute [...] Read more.
Flavour in Scotch malt whisky is a key differentiating factor for consumers and producers alike. Yeast (commonly Saccharomyces cerevisiae) metabolites produce a significant amount of this flavour as part of distillery fermentations, as well as ethanol and carbon dioxide. Whilst yeast strains contribute flavour, there is limited information on the relationship between yeast strain and observed flavour profile. In this work, the impact of yeast strain on the aroma profile of new make spirit (freshly distilled, unmatured spirit) was investigated using 24 commercially available active dried yeast strains. The contribution of alcoholic, fruity, sulfury and sweet notes to new make spirit by yeast was confirmed. Generally, distilling strains could be distinguished from brewing and wine strains based on aroma and ester concentrations. However, no statistically significant differences between individual yeast strains could be perceived in the intensity of seven aroma categories typically associated with whisky. Overall, from the yeast strains assessed, it was found that new make spirit produced using yeast strains marketed as ‘brewing’ strains was preferred in terms of acceptability rating. Full article
(This article belongs to the Special Issue Yeast Biotechnology 5.0)
Show Figures

Figure 1

Article
Cellulosic Butanol Biorefinery: Production of Biobutanol from High Solid Loadings of Sweet Sorghum Bagasse—Simultaneous Saccharification, Fermentation, and Product Recovery
Fermentation 2021, 7(4), 310; https://doi.org/10.3390/fermentation7040310 - 14 Dec 2021
Cited by 1 | Viewed by 885
Abstract
Butanol was produced commercially from cornstarch and sugarcane molasses (renewable resources) until 1983, when production of these plants was forced to cease because of unfavorable economics of production caused in part by escalating prices of these feedstocks. During recent years, the focus of [...] Read more.
Butanol was produced commercially from cornstarch and sugarcane molasses (renewable resources) until 1983, when production of these plants was forced to cease because of unfavorable economics of production caused in part by escalating prices of these feedstocks. During recent years, the focus of research has been on the use of economically available agricultural biomass and residues and cutting-edge science and technology to make butanol production a commercially viable process again. In this study, we produced butanol from sweet sorghum bagasse (SSB) by employing high concentrations of SSB solids and integrated process technology through which simultaneous saccharification, fermentation, and recovery (SSFR) were conducted as one unit operation. The concentrated SSB (16–22% dry wt. basis or 160–220 gL−1) was used to reduce reactor size and potentially reduce fixed and operational costs. Indeed, ABE productivity and yield of 0.21 gL−1h−1 and 0.39 were obtained, respectively, when 160 gL−1 SSB (16%, dry wt.) was used in the SSFR process. In nonintegrated systems, use of >90 gL−1 solid loading is improbable and has not been done until this study. Full article
(This article belongs to the Section Industrial Fermentation)
Show Figures

Figure 1

Article
Co-Treatment with Single and Ternary Mixture Gas of Dimethyl Sulfide, Propanethiol, and Toluene by a Macrokinetic Analysis in a Biotrickling Filter Seeded with Alcaligenes sp. SY1 and Pseudomonas Putida S1
Fermentation 2021, 7(4), 309; https://doi.org/10.3390/fermentation7040309 - 14 Dec 2021
Viewed by 841
Abstract
The biotrickling filter (BTF) treatment is an effective way of dealing with air pollution caused by volatile organic compounds (VOCs). However, this approach is typically used for single VOCs treatment but not for the mixtures of VOC and volatile organic sulfur compounds (VOSCs), [...] Read more.
The biotrickling filter (BTF) treatment is an effective way of dealing with air pollution caused by volatile organic compounds (VOCs). However, this approach is typically used for single VOCs treatment but not for the mixtures of VOC and volatile organic sulfur compounds (VOSCs), even if they are often encountered in industrial applications. Therefore, we investigated the performance of BTF for single and ternary mixture gas of dimethyl sulfide (DMS), propanethiol, and toluene, respectively. Results showed that the co-treatment enhanced the removal efficiency of toluene, but not of dimethyl sulfide or propanethiol. Maximum removal rates (rmax) of DMS, propanethiol and toluene were calculated to be 256.41 g·m−3·h−1, 204.08 g·m−3·h−1 and 90.91 g·m−3·h−1, respectively. For a gas mixture of these three constituents, rmax was measured to be 114.94 g·m−3·h−1, 104.17 g·m−3·h−1 and 99.01 g·m−3·h−1, separately. Illumina MiSeq sequencing analysis further indicated that Proteobacteria and Bacteroidetes were the major bacterial groups in BTF packing materials. A shift of bacterial community structure was observed during the biodegradation process. Full article
Show Figures

Graphical abstract

Article
Influence of Salinity on the Microbial Community Composition and Metabolite Profile in Kimchi
Fermentation 2021, 7(4), 308; https://doi.org/10.3390/fermentation7040308 - 13 Dec 2021
Cited by 4 | Viewed by 1188
Abstract
Kimchi, a popular traditional Korean fermented food, is produced by fermenting vegetables with various spices and salt. Salt plays an important role in the preparation of kimchi and affects its taste and flavor. This study aimed to investigate the effects of salinity on [...] Read more.
Kimchi, a popular traditional Korean fermented food, is produced by fermenting vegetables with various spices and salt. Salt plays an important role in the preparation of kimchi and affects its taste and flavor. This study aimed to investigate the effects of salinity on kimchi fermentation. The salinities of five sets of kimchi samples were adjusted to 1.4%, 1.7%, 2.0%, 2.2%, and 2.5%. The characteristics of each kimchi sample, including its pH, acidity, free sugar content, free amino acid content, organic acid content, and microbial community composition, were evaluated during kimchi fermentation. The low-salinity kimchi sample showed a rapid decline in the pH at the beginning of the fermentation process, a relatively high abundance of Leuconostoc mesenteroides, and high mannitol production. In the late fermentation period, Latilactobacillus sakei had a higher abundance in the kimchi sample with high salinity than in other samples. In the initial stage of fermentation, the metabolite composition did not differ based on salinity, whereas the composition was considerably altered from the third week of fermentation. The findings showed variations in the characteristics and standardized manufacturing processes of kimchi at various salt concentrations. Therefore, salinity significantly affected the types and concentrations of fermentation metabolites in kimchi. Full article
(This article belongs to the Special Issue Fermentation and Bioactive Metabolites 3.0)
Show Figures

Graphical abstract

Review
Current Advances in Microbial Production of Acetoin and 2,3-Butanediol by Bacillus spp.
Fermentation 2021, 7(4), 307; https://doi.org/10.3390/fermentation7040307 - 13 Dec 2021
Cited by 1 | Viewed by 1652
Abstract
The growing need for industrial production of bio-based acetoin and 2,3-butanediol (2,3-BD) is due to both environmental concerns, and their widespread use in the food, pharmaceutical, and chemical industries. Acetoin is a common spice added to many foods, but also a valuable reagent [...] Read more.
The growing need for industrial production of bio-based acetoin and 2,3-butanediol (2,3-BD) is due to both environmental concerns, and their widespread use in the food, pharmaceutical, and chemical industries. Acetoin is a common spice added to many foods, but also a valuable reagent in many chemical syntheses. Similarly, 2,3-BD is an indispensable chemical on the platform in the production of synthetic rubber, printing inks, perfumes, antifreeze, and fuel additives. This state-of-the-art review focuses on representatives of the genus Bacillus as prospective producers of acetoin and 2,3-BD. They have the following important advantages: non-pathogenic nature, unpretentiousness to growing conditions, and the ability to utilize a huge number of substrates (glucose, sucrose, starch, cellulose, and inulin hydrolysates), sugars from the composition of lignocellulose (cellobiose, mannose, galactose, xylose, and arabinose), as well as waste glycerol. In addition, these strains can be improved by genetic engineering, and are amenable to process optimization. Bacillus spp. are among the best acetoin producers. They also synthesize 2,3-BD in titer and yield comparable to those of the pathogenic producers. However, Bacillus spp. show relatively lower productivity, which can be increased in the course of challenging future research. Full article
(This article belongs to the Special Issue Microbial Biotransformation by Bacillus)
Show Figures

Figure 1

Article
Optimization of Soybean Meal Fermentation for Aqua-Feed with Bacillus subtilis natto Using the Response Surface Methodology
Fermentation 2021, 7(4), 306; https://doi.org/10.3390/fermentation7040306 - 10 Dec 2021
Cited by 4 | Viewed by 1236
Abstract
This study aimed to improve the nutritional value of soybean meal (SBM) by solid-state fermentation (SSF) using Bacillus subtilis natto (B. s. natto) to overcome the limitations of SBM usage in aquafeed. The response surface methodology (RSM) was employed to explore [...] Read more.
This study aimed to improve the nutritional value of soybean meal (SBM) by solid-state fermentation (SSF) using Bacillus subtilis natto (B. s. natto) to overcome the limitations of SBM usage in aquafeed. The response surface methodology (RSM) was employed to explore the relationships of fermentation conditions, such as temperature, time, water-substrate ratio, and layer thickness, on the degree of protein hydrolysis (DH) and the crude protein (CP) content. The optimum conditions for achieving the higher DH (15.96%) and CP (55.76%) were 43.82 °C, 62.32 h, 1.08 of water-substrate ratio, and a layer thickness of 2.02 cm. CP and DH in the fermented soybean meal (FSM) increased by 9.8% and 177.1%, respectively, and crude fiber decreased by 14.1% compared to SBM. The protein dispersibility index (PDI) decreased by 29.8%, while KOH protein solubility (KPS) was significantly increased by 17.4%. Flavonoids and total phenolic acid content in FSM were increased by 231.0% and 309.4%, respectively. Neutral protease activity (NPA) also reached a high level (1723.6 U g−1). Total essential amino acids (EAA) in FSM increased by 12.2%, higher than the 10.8% increase of total non-essential amino acids (NEAA), while the total free amino acids content was 12.76 times higher than that of SBM. Major anti-nutritional factors in SBM were significantly reduced during the process, and almost all SBM protein macromolecules were decomposed. Together with the cost-effectiveness of SSF, B. s. natto-fermented SBM products have great potential to improve the plant composition and replace high-cost ingredients in aquafeed, contributing to food security and environmental sustainability. Full article
(This article belongs to the Topic Bioreactors: Control, Optimization and Applications)
Show Figures

Figure 1

Article
Green Husk of Walnuts (Juglans regia L.) from Southern Italy as a Valuable Source for the Recovery of Glucans and Pectins
Fermentation 2021, 7(4), 305; https://doi.org/10.3390/fermentation7040305 - 10 Dec 2021
Cited by 3 | Viewed by 961
Abstract
Walnut green husk is an agricultural waste produced during the walnut (Juglans regia L.) harvest, that could be valued as a source of high-value compounds. In this respect, walnut green husks from two areas of Southern Italy (Montalto Uffugo and Zumpano), with [...] Read more.
Walnut green husk is an agricultural waste produced during the walnut (Juglans regia L.) harvest, that could be valued as a source of high-value compounds. In this respect, walnut green husks from two areas of Southern Italy (Montalto Uffugo and Zumpano), with different soil conditions, were investigated. Glucans and pectins were isolated from dry walnut husks by carrying out alkaline and acidic extractions, respectively, and then they were characterized by FT-IR, scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The colorimetric method for the enzymatic measurement of α- and β-glucans was performed. The maximum total glucan yield was recovered from Montalto walnut husks (4.6 ± 0.2 g/100 g DM) with a β-glucan percentage (6.3 ± 0.4) higher than that calculated for Zumpano walnut husks (3.6 ± 0.5). Thermal analysis (DSC) confirmed the higher degree of crystallinity of glucans from Zumpano. The pectin content for Montalto husks was found to be 2.6 times that of Zumpano husks, and the esterification degree was more than 65%. The results suggested that J. regia L. green husks could be a source of glucans and pectins, whose content and morphological and thermal characteristics were influenced by different soil and climate conditions. Full article
(This article belongs to the Special Issue Food Waste Valorization)
Show Figures

Graphical abstract

Review
Valorization of Macroalgae through Fermentation for Aquafeed Production: A Review
Fermentation 2021, 7(4), 304; https://doi.org/10.3390/fermentation7040304 - 10 Dec 2021
Viewed by 946
Abstract
The increased development of aquaculture has resulted in increased demand for high-protein aquafeed. An increased demand for high-protein aquafeed means an increase in exploitation of unsustainable protein sources such as fishmeal for aquafeed production. Thus, alternative protein sources such as fermented macroalgae is [...] Read more.
The increased development of aquaculture has resulted in increased demand for high-protein aquafeed. An increased demand for high-protein aquafeed means an increase in exploitation of unsustainable protein sources such as fishmeal for aquafeed production. Thus, alternative protein sources such as fermented macroalgae is explored. Fermented macroalgae had been tested as aquaculture diets in some studies, but with limited coverage in relation to aquaculture. Therefore, this review provides a new perspective regarding their nutritional qualities as aquaculture diets, and their impacts on growth performances of aquaculture animals. Full article
(This article belongs to the Section Microbial Metabolism, Physiology & Genetics)
Article
Volatile Fatty Acids (VFA) Production from Wastewaters with High Salinity—Influence of pH, Salinity and Reactor Configuration
Fermentation 2021, 7(4), 303; https://doi.org/10.3390/fermentation7040303 - 09 Dec 2021
Cited by 2 | Viewed by 985
Abstract
The hydrocarbon-based economy is moving at a large pace to a decarbonized sustainable bioeconomy based on biorefining all types of secondary carbohydrate-based raw materials. In this work, 50 g L−1 in COD of a mixture of food waste, brine and wastewater derived [...] Read more.
The hydrocarbon-based economy is moving at a large pace to a decarbonized sustainable bioeconomy based on biorefining all types of secondary carbohydrate-based raw materials. In this work, 50 g L−1 in COD of a mixture of food waste, brine and wastewater derived from a biodiesel production facility were used to produce organic acids, important building-blocks for a biobased industry. High salinity (12–18 g L−1), different reactors configuration operated in batch mode, and different initial pH were tested. In experiment I, a batch stirred reactor (BSR) at atmospheric pressure and a granular sludge bed column (GSBC) were tested with an initial pH of 5. In the end of the experiment, the acidification yield (ηa) was similar in both reactors (22–24%, w/w); nevertheless, lactic acid was in lower concentrations in BSR (6.3 g L−1 in COD), when compared to GSBC (8.0 g L−1 in COD), and valeric was the dominant acid, reaching 17.3% (w/w) in the BSR. In experiment II, the BSR and a pressurized batch stirred reactor (PBSR, operated at 6 bar) were tested with initial pH 7. The ηa and the VFA concentration were higher in the BSR (46%, 22.8 g L−1 in COD) than in the PBSR (41%, 20.3 g/L in COD), and longer chain acids were more predominant in BSR (24.4% butyric, 6.7% valeric, and 6.2% caproic acids) than in PBSR (23.2%, 6.2%, and 4.2%, respectively). The results show that initial pH of 7 allows achieving higher ηa, and the BSR presents the most suitable reactor among tested configurations to produce VFA from wastes/wastewaters with high salinity. Full article
(This article belongs to the Special Issue Food Wastes: Feedstock for Value-Added Products 3.0)
Show Figures

Graphical abstract

Article
A Method for WWTP Sludge Valorization through Hygienization by Electron Beam Treatment
Fermentation 2021, 7(4), 302; https://doi.org/10.3390/fermentation7040302 - 09 Dec 2021
Cited by 1 | Viewed by 708
Abstract
This work reports on municipal sludge hygienization using electron beams. Three types of sewage sludge from two municipal wastewater treatment plants were tested: preliminary sludge with 4% TS, postflotation sludge with 2.5% TS and thickened preliminary sludge with 10% TS. The analysis of [...] Read more.
This work reports on municipal sludge hygienization using electron beams. Three types of sewage sludge from two municipal wastewater treatment plants were tested: preliminary sludge with 4% TS, postflotation sludge with 2.5% TS and thickened preliminary sludge with 10% TS. The analysis of reference samples demonstrated the presence of bacteria and helminths ova in all examined samples. For the study of hygienization, electron beams from two types of accelerators, linear (Elektronika 10/10) and single cavity (ILU-6), were applied. For each type of accelerator, different irradiation methods were used: irradiation in sealed polyethylene bags using conveyor and flow irradiation installation. Experiments showed that the doses necessary for the elimination of mentioned pathogens were 4 kGy for preliminary sludge, 4 kGy for postflotation sludge and 5.5 kGy for preliminary sludge. The differences between the amounts of initial pathogens in preliminary and thickened preliminary sludge were marginal. It is possible that the higher irradiation dose required to hygienize thickened sludge resulted from higher TS concentration. Full article
(This article belongs to the Special Issue Recent Trends in Biogenic Gas, Waste and Wastewater Fermentation)
Show Figures

Figure 1

Article
Studies on Proximate Composition, Mineral and Total Phenolic Content of Yogurt Bites Enriched with Different Plant Raw Material
Fermentation 2021, 7(4), 301; https://doi.org/10.3390/fermentation7040301 - 09 Dec 2021
Cited by 1 | Viewed by 891
Abstract
Yogurt products are consumed by millions of people every day. Consumers’ priority for ready-to-eat yogurt snacks enriched with various plant raw materials have increased each year. Therefore, the aim of this study was to prepare freeze-dried yoghurt bites with the addition of powders [...] Read more.
Yogurt products are consumed by millions of people every day. Consumers’ priority for ready-to-eat yogurt snacks enriched with various plant raw materials have increased each year. Therefore, the aim of this study was to prepare freeze-dried yoghurt bites with the addition of powders of beetroot, mulberry leaves, nettle leaves and rosehip fruit and to investigate these raw materials’ influence on the proximate composition, mineral and total phenolic content. The moisture, protein, fat, carbohydrate and sugar content of the yogurt bites were established using standard methods: mineral composition—using an inductively coupled plasma mass spectrometer (ICP-MS); total phenolic content—by the spectrophotometric method. The results demonstrated that the addition of different raw material powders to the formulation of yogurt bites had no significant influence on carbohydrate, protein and total fat amounts. However, the incorporation of powders of beetroot, mulberry leaves, nettle leaves and rosehip fruit in yogurt bites allowed a significant increase of the amounts of all investigated minerals and total phenolic content of the manufactured bites. Among all investigated yogurt bites, the highest amounts of K, P, Mg, Fe and Zn were determined for yogurt bites enriched with nettle leaves. In conclusion, the enrichment of yogurt bites with freeze-dried plant raw material powders can increase amounts of selected minerals and total phenolic content. Full article
(This article belongs to the Section Fermentation for Food and Beverages)
Show Figures

Figure 1

Article
Submerged Fermentation of Animal Fat By-Products by Oleaginous Filamentous Fungi for the Production of Unsaturated Single Cell Oil
Fermentation 2021, 7(4), 300; https://doi.org/10.3390/fermentation7040300 - 09 Dec 2021
Viewed by 855
Abstract
Animal waste fats were explored as a fermentation substrate for the production of high-value unsaturated single cell oil (SCO) using oleaginous fungi, Mucor circinelloides and Mortierella alpina. Both strains showed good growth and lipid accumulation when using animal fat as a single [...] Read more.
Animal waste fats were explored as a fermentation substrate for the production of high-value unsaturated single cell oil (SCO) using oleaginous fungi, Mucor circinelloides and Mortierella alpina. Both strains showed good growth and lipid accumulation when using animal fat as a single carbon source. The biomass concentration of 16.7 ± 2.2 gDCW/L and lipid content of 54.1%wt (of dry cell weight) were obtained for Mucor circinelloides in shake flask experiments, surpassing the biomass yield achieved in batch and fed-batch fermentation. In contrast, Mortierella alpina gave the highest biomass concentration (8.3 ± 0.3 gDCW/L) and lipid content (55.8%wt) in fed-batch fermentation. Fat grown Mortierella alpina was able to produce arachidonic acid (ARA), and the highest ARA content of 23.8%wt (of total lipid weight) was in fed-batch fermentation. Gamma-linolenic acid (GLA) was produced by both fungal strains. At the end of fed-batch fermentation, the GLA yields obtained for Mucor circinelloides and Mortierella alpina were 4.51%wt and 2.77%wt (of total lipid weight), respectively. This study demonstrates the production of unsaturated SCO-rich fungal biomass from animal fat by fermentation. Full article
(This article belongs to the Special Issue Food Wastes: Feedstock for Value-Added Products 3.0)
Show Figures

Figure 1

Review
Strategies to Increase the Value of Pomaces with Fermentation
Fermentation 2021, 7(4), 299; https://doi.org/10.3390/fermentation7040299 - 08 Dec 2021
Cited by 4 | Viewed by 1053
Abstract
The generation of pomaces from juice and olive oil industries is a major environmental issue. This review aims to provide an overview of the strategies to increase the value of pomaces by fermentation/biotransformation and explore the different aspects reported in scientific studies. Fermentation [...] Read more.
The generation of pomaces from juice and olive oil industries is a major environmental issue. This review aims to provide an overview of the strategies to increase the value of pomaces by fermentation/biotransformation and explore the different aspects reported in scientific studies. Fermentation is an interesting solution to improve the value of pomaces (especially from grape, apple, and olive) and produce high-added value compounds. In terms of animal production, a shift in the fermentation process during silage production seems to happen (favoring ethanol production rather than lactic acid), but it can be controlled with starter cultures. The subsequent use of silage with pomace in animal production slightly reduces growth performance but improves animal health status. One of the potential applications in the industrial context is the production of enzymes (current challenges involve purification and scaling up the process) and organic acids. Other emerging applications are the production of odor-active compounds to improve the aroma of foods as well as the release of bound polyphenols and the synthesis of bioactive compounds for functional food production. Full article
(This article belongs to the Special Issue Food Waste Valorization)
Show Figures

Figure 1

Article
Kinetics of In Vitro Gas Production and Fitting Mathematical Models of Corn Silage
Fermentation 2021, 7(4), 298; https://doi.org/10.3390/fermentation7040298 - 08 Dec 2021
Cited by 1 | Viewed by 811
Abstract
This study aimed at examining the effects of rumen inoculum of steers receiving different combinations of ionophore and probiotics in their diets on in vitro gas production of corn silage. The fitting of gas production was performed with five mathematical models and its [...] Read more.
This study aimed at examining the effects of rumen inoculum of steers receiving different combinations of ionophore and probiotics in their diets on in vitro gas production of corn silage. The fitting of gas production was performed with five mathematical models and its kinetics was evaluated. Four crossbred steers (403.0 ± 75.5 kg body weight) with ruminal cannula were assigned to a 4 × 4 Latin square design. The additives used were Monensin sodium (Rumensin® 100, 3 g/day), Bacillus toyonensis (Micro-Cell Platinum® 109, 1 g/day) and Saccharomyces cerevisiae boulardii (ProTernative®20, 0.5 g/day). Additives were arranged into the following treatments, supplied daily into total mixed diet: (1) Monensin; (2) Monensin + B. toyonensis; (3) Monensin + S. boulardii; and (4) B. toyonensis + S. boulardii. The gas production data were fitted into the models of Gompertz, Groot, Ørskov, Brody, Richards, and Dual-pool Logistic. A perfect agreement between observed and predicted values in curves of accumulated in vitro gas production was observed in the Groot and Richards models, with higher coefficient of determination (R2 = 0.770 and 0.771, respectively), concordance correlation coefficient (CCC = 0.871 and 0.870, respectively), and root mean square error of prediction (RMSEP = 1.14 and 1.15, respectively). Evaluating the feed additives throughout the Groot model, the B. toyonensis + S. boulardii treatment presented higher VF (12.08 mL/100 mg of DM; p = 0.0022) than Monensin and Monensin + S. boulardii (9.16 and 9.22 mL/100 mg of DM, respectively). In addition, the fractional rate of gas production (k) was higher (p = 0.0193) in B. toyonensis + S. boulardii than in Monensin, not presenting a statistical difference (p > 0.05) from the other two treatments. Additionally, with the time of beginning to gas production, the lag time (λ), was greater (p < 0.001) with Monensin and Monensin + B. toyonensis than with Monensin + S. boulardii and B. toyonensis + S. boulardii. The combination of Monensin and probiotics (B. toyonensis + S. boulardii) resulted in better kinetics of degradation of corn silage, being that the Groot and Richards models had the best fit for estimates of the in vitro gas production data of corn silage tested with different feed additive combinations. Full article
(This article belongs to the Section Fermentation Process Design)
Show Figures

Figure 1

Article
Bioconversion of Ginsenosides in American Ginseng Extraction Residue by Fermentation with Ganoderma lucidum Improves Insulin-like Glucose Uptake in 3T3-L1 Adipocytes
Fermentation 2021, 7(4), 297; https://doi.org/10.3390/fermentation7040297 - 06 Dec 2021
Viewed by 988
Abstract
Ginseng is one of the most popular traditional Chinese medicines that have been widely used in China and other Asian countries for thousands of years. Ginsenosides are the unique bioactive saponins occurring in ginseng, and their biological activities have been extensively investigated. A [...] Read more.
Ginseng is one of the most popular traditional Chinese medicines that have been widely used in China and other Asian countries for thousands of years. Ginsenosides are the unique bioactive saponins occurring in ginseng, and their biological activities have been extensively investigated. A large amount of ginseng residue is produced as waste product due to its applications in manufacturing functional food products, even though it may still contain bioactive components. Thus, the objective of this study was to investigate the hypoglycemic activities of American ginseng extraction residue (AmR) via fermentation with Ganoderma lucidum. Our results showed that the total phenolic contents and β-glucosidase activity of AmR profoundly increased after fermentation with G. lucidum. In 3T3-L1 adipocytes, stimulation of glucose uptake by treatment with AmR was not significant, while fermented AmR (FAmR) exhibited insulin-like glucose-uptake-stimulatory effects. Importantly, the hypoglycemic effects of FAmR were positively associated with the amount of the deglycosylated minor ginsenosides Rg1, Rg3, and compound K. Taken together, our current findings suggest that bioconversion of AmR by fermentation with G. lucidum may be a feasible and eco-friendly approach to developing a functional ingredient for the management of diabetes, while also resolving the problem of ginseng waste. Full article
(This article belongs to the Special Issue Food Fermentation for Better Nutrition, Health and Sustainability)
Show Figures

Figure 1

Article
Plant Biomass Production in Constructed Wetlands Treating Swine Wastewater in Tropical Climates
Fermentation 2021, 7(4), 296; https://doi.org/10.3390/fermentation7040296 - 02 Dec 2021
Cited by 3 | Viewed by 1018
Abstract
The production of both aboveground and belowground plant biomass in constructed wetlands (CW) is a poorly understood topic, although vegetation plays an important role in the process of pollutant removal from wastewater. The objective of this study was to evaluate the aboveground and [...] Read more.
The production of both aboveground and belowground plant biomass in constructed wetlands (CW) is a poorly understood topic, although vegetation plays an important role in the process of pollutant removal from wastewater. The objective of this study was to evaluate the aboveground and belowground biomass production of Typha latifolia and Canna hybrids in a large-scale constructed wetland treating swine wastewater in tropical climates. Parameters, such as temperature, DO, pH, COD, TSS, TN, TP, and TC, as well as destructive and non-destructive biomass, were evaluated. It was found that, despite the high concentrations of pollutants, the vegetation adapted easily and also grew healthily despite being exposed to high concentrations of pollutants from swine water. Although Typha latifolia (426 plants) produced fewer plants than Canna hybrids (582 plants), the higher biomass of the Typha latifolia species was slightly higher than that of Canna hybrids by 5%. On the other hand, the proximity of the water inlet to the system decreased the capacity for the development of a greater number of seedlings. As for the elimination of pollutants, after treatment in the constructed wetland, COD: 83.6 ± 16.9%; TSS: 82.2 ± 17.7%; TN: 94.4 ± 15.8%; TP: 82.4 ± 23.2%; and TC: 94.4 ± 4.4% were significantly reduced. These results show that wetlands constructed as tertiary systems for the treatment of swine wastewater produce a large amount of plant biomass that significantly helps to reduce the concentrations of pollutants present in this type of water in tropical areas. The use of these plants is recommended in future wetland designs to treat swine wastewater. Full article
(This article belongs to the Special Issue Recent Trends in Biogenic Gas, Waste and Wastewater Fermentation)
Show Figures

Figure 1

Article
Production of Pigments by Filamentous Fungi Cultured on Agro-Industrial by-Products Using Submerged and Solid-State Fermentation Methods
Fermentation 2021, 7(4), 295; https://doi.org/10.3390/fermentation7040295 - 02 Dec 2021
Cited by 2 | Viewed by 1085
Abstract
The food and pharmaceutical industries are searching for natural colour alternatives as required by consumers. Over the last decades, fungi have emerged as producers of natural pigments. In this paper, five filamentous fungi; Penicillium multicolour, P. canescens, P. herquie, Talaromyces verruculosus [...] Read more.
The food and pharmaceutical industries are searching for natural colour alternatives as required by consumers. Over the last decades, fungi have emerged as producers of natural pigments. In this paper, five filamentous fungi; Penicillium multicolour, P. canescens, P. herquie, Talaromyces verruculosus and Fusarium solani isolated from soil and producing orange, green, yellow, red and brown pigments, respectively, when cultured on a mixture of green waste and whey were tested. The culture media with varying pH (4.0, 7.0 and 9.0) were incubated at 25 °C for 14 days under submerged and solid-state fermentation conditions. Optimal conditions for pigment production were recorded at pH 7.0 and 9.0 while lower biomass and pigment intensities were observed at pH 4.0. The mycelial biomass and pigment intensities were significantly higher for solid-state fermentation (0.06–2.50 g/L and 3.78–4.00 AU) compared to submerged fermentation (0.220–0.470 g/L and 0.295–3.466 AU). The pigment intensities were corroborated by lower L* values with increasing pH. The λmax values for the pigments were all in the UV region. Finally, this study demonstrated the feasibility of pigment production using green waste:whey cocktails (3:2). For higher biomass and intense pigment production, solid-state fermentation may be a possible strategy for scaling up in manufacturing industries. Full article
(This article belongs to the Special Issue Food Wastes: Feedstock for Value-Added Products 3.0)
Show Figures

Figure 1

Article
Supplemental Aspergillus Lipase and Protease Preparations Display Powerful Bifidogenic Effects and Modulate the Gut Microbiota Community of Rats
Fermentation 2021, 7(4), 294; https://doi.org/10.3390/fermentation7040294 - 01 Dec 2021
Cited by 2 | Viewed by 927
Abstract
Aspergillus-derived protease and lipase, which are involved in the production of Aspergillus-fermented foods, are consumed as digestive enzyme supplements. A marked bifidogenic effect of supplemental Aspergillus protease preparation (AP) in rats fed with a high-fat diet was identified. This study was [...] Read more.
Aspergillus-derived protease and lipase, which are involved in the production of Aspergillus-fermented foods, are consumed as digestive enzyme supplements. A marked bifidogenic effect of supplemental Aspergillus protease preparation (AP) in rats fed with a high-fat diet was identified. This study was conducted to examine whether the consumption of Aspergillus-derived lipase exerts similar bifidogenic effect. Rats were fed diets supplemented with either an Aspergillus-derived lipase preparation (AL) or AP at 0.1% for two weeks. 16S rRNA gene sequencing analysis indicated that supplemental AL and AP markedly influenced cecal microbial community. At the phylum level, treatment with AL and AP resulted in a lower relative abundance of Firmicutes and Bacteroidetes, but a higher relative abundance of Actinobacteria and Proteobacteria than the control rats (p < 0.05). At the genus level, AL and AP remarkedly elevated the relative abundances of Bifidobacterium, Collinsella, and Enterococcus, but significantly reduced those of Oscillospira, Dorea, and Coprobacillus (p < 0.05). These modulations were similar to those reported by several studies with typical prebiotic oligosaccharides. Notably, the bifidogenic effect of AL was much greater than that of AP. Our results show that the two different Aspergillus-derived preparations, AL and AP, have strong bifidogenic effects and can change the microbiota’s composition. Full article
(This article belongs to the Special Issue Fermented Foods and Microbes Related to Health)
Show Figures

Graphical abstract

Article
Changes of Main Nutrient Components and Volatile Flavor Substances in Processing of Canned Bamboo Shoots
Fermentation 2021, 7(4), 293; https://doi.org/10.3390/fermentation7040293 - 01 Dec 2021
Cited by 1 | Viewed by 850
Abstract
Canned bamboo shoots, a popular endurable storage product preserved by canning, can be used directly as a raw material for preparing dishes and processing many other downstream products. Fermentation and high temperature sterilization are decisive for product quality. During 3 days of fermentation [...] Read more.
Canned bamboo shoots, a popular endurable storage product preserved by canning, can be used directly as a raw material for preparing dishes and processing many other downstream products. Fermentation and high temperature sterilization are decisive for product quality. During 3 days of fermentation at 25 °C, the protein and total amino acids of bamboo shoots increased remarkably and the total phenols changed a little. After steam sterilization, the total sugar decreased by 56.82%, and the protein of bamboo shoots decreased from 2.41 ± 0.04 g/100 g to 2.03 ± 0.30 g/100 g. The process significantly increased from zero the total sugar, protein and total amino acids in sterilization bamboo shoots soaking solution. GC-MS-ROAV was used for the detection of volatile flavor substances (VFCs) of bamboo shoots and soaking solution in the four processing stages. Fermented bamboo shoots after 72 h showed a strong aroma of orange oil, which was the evaluator’s preferred aroma. In the process of sterilization, Maillard reaction leads to the increase of pyrazines and furans in bamboo shoots and soaking solution, including dibenzofuran, furaneol, trimethyl-pyrazine and 2,3-dimethyl-pyrazine. Due to these volatile flavor components, the sterilized bamboo shoots spread a light caramel and cocoa flavor. Full article
(This article belongs to the Section Industrial Fermentation)
Show Figures

Graphical abstract

Article
Changes in Bioactive Compounds of Coffee Pulp through Fermentation-Based Biotransformation Using Lactobacillus plantarum TISTR 543 and Its Antioxidant Activities
Fermentation 2021, 7(4), 292; https://doi.org/10.3390/fermentation7040292 - 30 Nov 2021
Cited by 3 | Viewed by 1168
Abstract
The use of biotransformation has become a popular trend in the food and cosmetic industry. Lactic acid bacteria (LAB) are widely used due to their safety and beneficial effects on human health. Coffee pulp, a by-product obtained from coffee production, has antioxidant activity [...] Read more.
The use of biotransformation has become a popular trend in the food and cosmetic industry. Lactic acid bacteria (LAB) are widely used due to their safety and beneficial effects on human health. Coffee pulp, a by-product obtained from coffee production, has antioxidant activity because it contains different classes of phenolic compounds. To investigate the factors affecting the biotransformation process of coffee pulp using L. plantarum TISTR 543, a systematic study using 23 factorial designs in a completely randomized design (CRD) was done. After the coffee pulp was bio-transformed, its bacterial count, pH, phenol contents, flavonoid contents, tannin contents, changes in bioactive compounds by LC-QQQ, and antioxidant properties were studied. The highest phenolic content was obtained in the sample containing the substrate, water, and sugar in the ratio of 3:10:3 with a 5% starter. After the fermentation was done, for 24–72 h, total bacteria count, total phenol contents, and antioxidant activities significantly increased compared to their initial values. Protocatechuic acid also markedly increased after 24 h of the biotransformation process. Hence, the fermentation of coffee pulp with L. plantarum TISTR 543 can produce substances with a higher biological activity which can be further studied and used as functional foods or active ingredients in cosmetic application. Full article
(This article belongs to the Section Fermentation Process Design)
Show Figures

Figure 1

Previous Issue
Next Issue
Back to TopTop