Growth Of Lactic Acid Bacteria Research Articles

Replacement of alkaline phosphate with flaxseed cake and its impact on mortadella's technological, oxidative, microbiological, and sensory aspects

SummaryThis study explored the replacement of alkaline phosphate (AP) with flaxseed cake (FC) in mortadella, assessing the impact on technological, oxidative, microbiological, and sensory properties. The inclusion of FC proved promising in maintaining emulsion stability, cooking loss, and water‐holding capacity and did not significantly affect colour characteristics, as indicated by the ΔE values (<5). Sensory analysis validated the substitution, highlighting the absence of a sandy texture sensation and FC's ability to suppress sensory defects caused by the removal of AP. However, adding FC decreased texture parameters such as hardness and cohesiveness, which can be leveraged in formulating products for specific niches, like older adults. Adding FC did not favour mesophilic aerobic and lactic acid bacteria growth. Nevertheless, the TBARS values of the mortadellas with FC increased (peaking at 0.5 mg MDA kg−1), but the sensory detection limit was not reached even at the end of storage.

Formulating edible films with red pitahaya extract and probiotic

Preventing food spoilage and prolonging its shelf life are of great importance to meet the increasing food demand. Dietary fibers in red pitahaya are known to help maintain food freshness. Lactic acid bacteria have probiotic properties and can be a good alternative to additives in food production. Therefore, we aimed to investigate the potential use of gum-based edible films containing red pitahaya extract and probiotic as a coating material in the food industry. Firstly, we determined the antimicrobial activity of red pitahaya peel and flesh extracts against pathogenic microorganisms and probiotic strains. Then, we employed the well diffusion method to determine the antimicrobial activity of the edible films containing red pitahaya extracts and Limosilactobacillus fermentum MA-7 used as a probiotic strain. The largest inhibition zone diameters of peel and flesh extracts were 12.97 and 13.32 mm, respectively, against Candida albicans ATCC 10231. The inhibition of the growth of lactic acid bacteria was lower as the extract concentration decreased. The gum-based films with flesh extract and probiotic had the largest inhibition zone diameters of 21.63 and 21.52 mm, respectively, against Aeromonas hydrophila ATCC19570 and C. albicans ATCC 10231. The edible films containing red pitahaya extract and L. fermentum MA-7 may have the potential to prevent spoilage caused by microorganisms in the food industry and to extend the shelf life of foods.

Sodium content in fermented shrimp paste with varying packaging materials

Shrimp and fish paste are fermented products with high amounts of added salt. Sodium (Na+ ) ions in salt are growth factors for halophilic lactic acid bacteria (LAB), essential in shrimp paste. However, an overabundance of Na+ negatively affects the human body and may increase blood pressure and the risk of heart attacks, strokes, kidney damage, and other health issues. Commercial shrimp paste can be found in various packaging materials. The permeability of the packaging material affects air availability during fermentation, which affects LAB growth and sodium levels. This study aimed to determine the effect different packaging materials have on rebon (Acetes sp.) shrimp paste sodium levels, precisely that of teak leaf, paper, and plastic. A completely randomized design and an experimental laboratory were used for the experiments. The data were analyzed using ANOVA and Honest Significant Differences tests. The different packaging materials significantly affected (P < 5%) the acidity, sodium levels, and total plate count (TPC) of LAB but did not affect the water activity or salt content. Shrimp paste consisted of 1.32±0.12% sodium when packaged in teak leaves, 1.51±0.08% in paper packaging, and 1.69±0.07% in plastic packaging. Teak leaves packaging resulted in shrimp paste with the lowest sodium content because of its many pores and high gas permeability, thus supporting the growth of microbes that use Na+ .

Immunoenhancing and antioxidant potentials of kimchi, an ethnic food from Korea, as a probiotic and postbiotic food

Kimchi, the traditional lactic fermented vegetables from Korea, is globally praised for its potential as a functional food owing to the presence of beneficial microorganisms known as probiotics. However, the serving of kimchi in traditional Korean dishes often involves cooking at high temperature, thus killing the probiotics. Recently, non-viable or inactivated microorganisms and their metabolites, known as postbiotics, were shown to confer health benefits when consumed, thus giving rise to a novel potential of kimchi as a postbiotic food with health functionalities. The present study aimed to explore the potential of uncooked and cooked kimchi, both as a probiotic and postbiotic food, respectively, using an animal model. Mice were fed by AIN-76 diet enriched in 10% freeze-dried uncooked or cooked kimchi for 28 days prior to kill. Several parameters related to immune system and antioxidant were evaluated. Exposure of kimchi toward heat in steaming process killed the microorganisms in kimchi, but did not alter its antioxidant activity. Interestingly, the consumption of uncooked and cooked kimchi stimulated the growth of lactic acid bacteria in the intestine indifferently, as shown in the fecal matter. In addition, kimchi supplementation, either uncooked or cooked, increased the number of splenic lymphocytes and intestinal IgA, supporting the role of kimchi in the immune system. Furthermore, kimchi supplementation reduced the level of lipid peroxidation in the fecal matter, indicating its antioxidant activity in vivo. Taken together, the findings in this study suggest the potential of kimchi both as a probiotic and postbiotic food with antioxidant and immunoenhancing properties.

Exopolysaccharides isolated from fermented milk-associated lactic acid bacteria and applied to produce functional value-added probiotic yogurt

The current study aimed to isolate and characterize the lactic acid bacteria (LAB)-derived exopolysaccharide (EPS) and apply it to enhance yogurt's functional and technological quality. After screening and isolation of 52 different LAB strains from fermented milk products, Lactobacillus (L.) rhamnosus KF5, L. plantarum C182, Pediococcus (P.) acidilactici CCFM18, and Leuconostoc (Leu.) mesenteroides F27, with high EPS production yield, were nominated for further evaluation. EPS-derived strains were evaluated based on production yield, protein content, antioxidant activity, emulsification, and anti-inflammatory ability. After comparing isolated EPS samples, the Leu. mesenteroides F27 products were chosen in 3 concentrations (100, 250, and 500 mg EPS/L) to supplement the yogurt. EPS at all concentrations enhanced LAB growth, water-holding capacity, viscosity, and antioxidant activity. The electronic nose and tongue revealed that EPS did not affect the yogurt flavor profile. The confocal laser scanning microscopy showed a homogenously distributed protein and EPS network in the supplemented yogurt samples. However, in the rheology and consumer analysis, the 250 mg/L concentration showed better attributes, such as higher consistency, lower flow behavior, and a higher flavor score. Leu. mesenteroides F27-derived EPS could be used as a biological additive to enhance yogurt's technological and functional quality.

Pulsed electric field‐assisted extraction of mushroom ß‐glucan from Pleurotus pulmonarius by‐product and study of prebiotic properties

SummaryPleurotus pulmonarius is one of the most widely consumed mushrooms containing low calories and fat. This study aimed to extract polysaccharides mainly ß‐glucan from P. pulmonarius by‐products including cap and stem using pulsed electric field (PEF) and study their prebiotic properties. The by‐products were subjected to PEF at a field strength of 5, 7.5 and 10 kV cm−1, a frequency of 15 Hz and a number of pulses of 12 000; then, the ß‐glucan content was determined with K‐YBGL assay test kit compared with a conventional extraction method using hot water at 100 °C for 6 h. In raw materials, crude carbohydrate contents in the cap and stem were 50.42% and 68.78%, respectively, and the ß‐glucan contents were 34.03% and 50.22%, respectively. After treated with PEF at 7.5 kV cm−1, the highest yield of 4.18% with ß‐glucan content of 14.10% was achieved. And the stem treated at 10 kV cm−1 showed the highest yield of 2.34% with ß‐glucan content of 21.39%. Comparatively lower yield and ß‐glucan contents were found in the samples treated with hot water. Scanning electron micrographs suggested that PEF caused severe damage to both samples. Additionally, the study of the prebiotic properties revealed that both products exhibited the ability to stimulate the growth of target lactic acid bacteria and the production of short‐chain fatty acid. This study suggested that PEF could enhance the extraction efficiency of β‐glucan with prebiotic potential from P. pulmonarius by‐products.

New generation of functional yogurts fermented with probiotic lactic acid bacteria isolated from human milk

Background: The cultures used in the production of "bio-yoghurts" typically consist of a blend of traditional yogurt starters, such as S. thermophilus and L. delbrueckii subsp. bulgaricus, along with probiotics like L. acidophilus, L. casei, L. reuteri, and Bifidobacterium spp. These probiotics, although beneficial, face challenges thriving in milk due to its short fermentation time (4–5 hours). The rapid acidification caused by the starter’s results in probiotic levels dropping below the "therapeutic minimum" during the intended refrigerated shelf life of the product. A potential solution to this issue lies in leveraging lactic acid bacteria isolated from the human milk which possess both robust probiotic characteristics and starter properties. Incorporating such strains in yogurt starter could address the acidity imbalance and contribute to maintaining optimal probiotic levels throughout the refrigerated shelf life of the product. Objective: This research aims to develop a new generation of sustainable functional yoghurts suitable for consumers of all ages using as starters predominant probiotic lactic acid bacteria isolated from the breast milk of healthy women. Results: This study marks the first implementation of the critical dilution culture method in sterile cow milk for the selection of predominant lactic acid bacteria (LABs) from women's breast milk. Remarkably, all samples yielded LAB capable of independently fermenting milk. Although breast milk is a good medium for the growth of residential lactic acid bacteria, it never coagulates due to low concentration of caseins. The isolated strains, identified as belonging to the species L. delbrueckii subsp. lactis, L. fermentum, L. casei subsp. sakei, Streptococcus thermophiles and Lactococcus lactis, exhibited probiotic and adaptive properties essential for gut colonization in humans. Utilizing symbiotic LAB starters were created functional yogurts with heightened technological, physicochemical, and sensory characteristics. Conclusions: Yogurts fermented using human milk LABs are safe and can be recommended as a functional dairy food, for pregnant women as well as for pre-term and full-term infants as a substitute/supplement for mother's milk. Moreover, these LABs can be included in infant formulas or used in pre-treatment of infant formula milk to improve its nutritional value and safety. Keywords: Breast milk, lactic acid bacteria, probiotic, milk fermentation, functional yogurt

Probiotic capacity of commensal lactic acid bacteria from the intestine of Guinea pigs (Cavia porcellus)

The intricate balance of intestinal microbiota is significantly influenced by the pivotal role of indigenous lactic acid bacteria (LAB). These LAB not only contribute to antimicrobial activity and enhance animal health and productivity but also serve as defense against intestinal infections. In the present study, the probiotic potential of LAB strains isolated from various intestinal sections of adult and young guinea pigs (Cavia porcellus) was comprehensively assessed. Strains belonging to the genera Ligilactobacillus, Weissella, Enterococcus, and Limosilactobacillus were also identified. The antibacterial activities of the LAB strains against Salmonella typhimurium, Escherichia coli, and Staphylococcus aureus were quantified. Exopolysaccharide production, adherence capacity, antibiotic resistance, and bile salt tolerance (0.15 %, 0.30 %, and 0.45 %) of LAB were quantified. Further analyses focused on the effects of pH (2.9, 5.0, 6.4, and 7.4), temperature (40, 50, and 60 °C) and NaCl concentrations (3.5 % and 6.5 % w/v) on LAB growth. Strains GCI9 and GDE10 (Ligilactobacillus salivarius), isolated from the cecum and intestine of guinea pigs, exhibited significant antimicrobial activity against S. typhimurium, E. coli and S. aureus. Remarkable adherence capacity to porcine gastric mucin was demonstrated by L. salivarius strains, specifically ACI1, GCI9, and GDE10, with the highest exopolysaccharide levels produced by ACI1 and GCI9 (1.71 and 1.76 mg/mL, respectively). The probiotic potential was further underscored by remarkable bile salt tolerance, especially in strain GDE10, and substantial exopolysaccharide production. These strains displayed notable adaptability to varying environmental conditions, including NaCl concentrations at 3.5 % and 6.5 %, temperatures ranging from 40 to 60 °C, and pH levels of 2.9, 5.0, 6.4, and 7.4. This comprehensive assessment of the probiotic properties of L. salivarius strains, particularly ACI1, GCI9, and GDE10, shows promise for the development of probiotic formulations aimed at enhancing the intestinal health of guinea pigs.

Effect of Mollusca shell extracts on inhibition of kimchi over-acidification

Mollusca species shell such as oyster shell (OS) and snail shell (SS), are discarded after taking the meat, and the discarded shell causes the environmental problems. Therefore, recycling shell waste could potentially eliminate the environmental problems. This study aimed to evaluate the potential of OS and SS as natural calcium resources. The minerals, calcium, magnesium, potassium, phosphorus and sodium were analyzed in OS and SS extracts. Among them, the calcium content was the highest: 36.87 (%) and 33.42 (%) in the OS and SS extracts, respectively. Further, the content of ionized bioavailable form of calcium in OS and SS was higher than that of CaCO3 under simulated gastrointestinal digestion conditions. Additionally, OS and SS were added to kimchi, and their inhibitory effect on kimchi acidification was evaluated by assessing pH, titratable acidity and microbial analysis. As the results indicated that the addition of OS and SS had little effect on inhibiting the growth of lactic acid bacteria. However, it was confirmed that calcium neutralizes the organic acids produced during fermentation. Overall, the results of this study provide preliminary information on the re-use of OS and SS extracts as ionized natural calcium supplements and fermentation retardants.

Potential Prebiotic Properties of Whey Protein and Glycomacropeptide in Gut Microbiome.

Proteins in whey have prebiotic and antimicrobial properties. Whey protein comprises numerous bioactive proteins and peptides, including glycomacropeptide (GMP), a hydrophilic casein peptide that separates with the whey fraction during cheese making. GMP has traditionally been used as a protein source for individuals with phenylketonuria and also has prebiotic (supporting the growth of Bifidobacterium and lactic acid bacteria) and antimicrobial activities. GMP supplementation may help positively modulate the gut microbiome, help treat dysbiosis-related gastrointestinal disorders and improve overall health in consumers.

Prebiotic Effect of Cogon Grass Root Extract on Stimulating Lactic Acid Bacteria Growth in Mice Intestine

Lactic acid bacteria (LAB) are known for their numerous beneficial effects for health and their colonization within intestines is affected by prebiotic consumption. Cogon grass root is an herbal medicine which contain substantial quantities of polyphenols. Recently, many studies suggested polyphenols as a novel group of prebiotics. Therefore, this study aimed to explore prebiotic effect of cogon grass root extract (CGRE) on stimulating growth of LAB in mice intestine. Mice (n =7/group) were divided into three groups; group A (control), group B and C received CGRE orally with daily dosage 90 and 115mg/kg BW, respectively. After 14 days of treatment, all mice were sacrificed. LAB was isolated and counted from ileum. Additional biochemical tests were performed to confirm the bacteria as LAB. Further identification of representatives LAB was performed with API-CHL-50 System. We found increased growth and diversity of LAB in the treatment group with optimum growth stimulation at CGRE dosage 90mg/KgBW daily (group B). Further identification showed Lactococcus lactis was the most frequent LAB found in all groups, with additional Lactobacillus paracasei and Lactobacillus curvatus were found in the treatment group. These findings support additional benefit of CGRE as prebiotics by stimulating LAB growth and diversity in mice intestine.

Enhancing the nutritional value and functional properties of mango pulp via lactic acid bacteria fermentation

The probiotic properties of four lactic acid bacteria (LAB) strains, Lacticaseibacillus paracasei OR1 and PP1 and Lacticaseibacillus rhamnosus MA3 and PP3, were evaluated. OR1 showed the highest levels of self-aggregation (61.27%) and coaggregation (17.70%) with Staphylococcus aureus. Compared to the crude cell-free supernatant (CFS) and ethyl acetate extract fraction, the water extract fraction of the CFS showed greater antimicrobial activity against Escherichia coli and Bacillus cereus. All LAB strains exhibited the highest levels of total carotenoids, phenolics, flavonoids and antioxidant activity in the CFS, suggesting that they can release water-soluble bioactive compounds into the growth medium. The phytochemical profile of Mahachanok mango, which is rich in bioactive compounds, was improved through LAB fermentation. LC–MS/MS analysis revealed 60 compounds, including phenolic acids (1.11-fold), organic acids (1.21-fold), and amino acid derivatives (1.28-fold), that were more abundant in the fermented Mahachanok mango pulp (FMP) samples than in the fresh samples. Interestingly, the antioxidant proline level increased 377.28-fold, and novel dipeptides and tripeptides were present in the FMP fermented with L. paracasei OR1. Mango pulp is a potential source of nutrients for LAB growth and metabolism; thus, LAB fermentation could be used to produce a functional food product rich in antioxidants and bioactive peptides.

High-throughput characterization of the effect of sodium chloride and potassium chloride on 31 lactic acid bacteria and their co-cultures.

Salt (NaCl) is associated with a risk of hypertension and the development of coronary heart disease, so its consumption should be limited. However, salt plays a key role in the quality and safety of food by controlling undesirable microorganisms. Since studies have focused primarily on the effect of salts on the overall counts of the lactic acid bacteria (LAB) group, we have not yet understood how salt stress individually affects the strains and the interactions between them. In this study, we characterized the effect of sodium chloride (NaCl) and potassium chloride (KCl) on the growth and acidification of 31 LAB strains. In addition, we evaluated the effect of salts on a total of 93 random pairwise strain combinations. Strains and co-cultures were tested at 3% NaCl, 5% NaCl, and 3% KCl on solid medium using an automated approach and image analysis. The results showed that the growth of LAB was significantly reduced by up to 68% at 5% NaCl (p < 0.0001). For the co-cultures, a reduction of up to 57% was observed at 5% NaCl (p < 0.0001). However, acidification was less affected by salt stress, whether for monocultures or co-cultures. Furthermore, KCl had a lesser impact on both growth and acidification compared to NaCl. Indeed, some strains showed a significant increase in growth at 3% KCl, such as Lactococcus lactis subsp. lactis 74310 (23%, p = 0.01). More importantly, co-cultures appeared to be more resilient and had more varied responses to salt stress than the monocultures, as several cases of suppression of the significant effect of salts on acidification and growth were detected. Our results highlight that while salts can modulate microbial interactions, these latter can also attenuate the effect of salts on LAB.

Bacillus velezensis promotes the proliferation of lactic acid bacteria and influences the fermentation quality of whole-plant corn silage.

This study aimed to investigate the promoting effect of a Bacillus velezensis (BV) strain on lactic acid bacteria (LAB) and determine its influence on the fermentation quality and aerobic stability of silage. Flat colony counting method was used to evaluate the effect of BV on the growth of LAB. Freshly harvested whole-plant corn was inoculated separately with BV and L. plantarum (LP), along with an uninoculated control group (CK), and assessed at 1, 3, 5, 7, 15, and 30 days of ensiling. The results indicated that BV exhibited a proliferative effect on Weissella confusa, Lactobacillus plantarum L-2, and Pediococcus pentosaceus. And exhibited a more rapid pH reduction in BV-inoculated silage compared with that in CK and LP-inoculated silage during the initial stage of ensiling. Throughout ensiling, the BV and LP experimental groups showed enhanced silage fermentation quality over CK. Additionally, relative to LP-inoculated silage, BV-inoculated silage displayed reduced pH and propionic acid. BV also prolonged aerobic stability under aerobic conditions. The microbial community in BV-inoculated silage showed greater stability than that in LP-inoculated silage. Additionally, Firmicutes and Lactobacillus exhibited more rapid elevation initially in BV versus LP-inoculated silage, but reached comparable levels between the two inoculation groups in the later stage. In summary, BV enhanced the efficacy and aerobic stability of whole-plant corn silage fermentation by stimulating LAB proliferation.

Bacteriocins against biogenic amine-accumulating lactic acid bacteria in cheese: nisin A shows the broadest antimicrobial spectrum and prevents the formation of biofilms

Cheese is a food in which toxic concentrations of biogenic amines (BA) may be reached, mainly as a consequence of the decarboxylation of determined amino acids by certain lactic acid bacteria (LAB). To maintain the food safety of cheese, environmentally friendly strategies are needed that specifically prevent the growth of BA-producing LAB and the accumulation of BA. The bacteriocins produced by LAB are natural compounds with great potential as food biopreservatives. This work examines the antimicrobial potential of 7 bacteriocin-containing, cell-free supernatants (CFS: coagulin A-CFS, enterocin A-CFS, enterocin P-CFS, lacticin 481-CFS, nisin A-CFS, nisin Z-CFS and plantaricin A-CFS) produced by LAB against 48 strains of the LAB species largely responsible for the accumulation of the most important BA in cheese, i.e., histamine, tyramine and putrescine. Susceptibility to the different CFS was strain-dependent. The histamine-producing species with the broadest sensitivity spectrum were Lentilactobacillus parabuchneri (the species mainly responsible for the accumulation of histamine in cheese) and Pediococcus parvulus. The tyramine-producing species with the broadest sensitivity spectrum was Enterococcus faecium, while Enterococcus faecalis and Enterococcus hirae were among the most sensitive putrescine producers. Nisin A-CFS was active against 31 of the 48 BA-producing strains (the broadest antimicrobial spectrum recorded). Moreover, commercial nisin A prevented biofilm formation by 67% of the BA-producing, biofilm-forming LAB strains. These findings underscore the potential of bacteriocins in the control of BA-producing LAB, and support the use of nisin A as a food grade biopreservative for keeping BA-producing LAB in check and reducing BA accumulation in cheese.

Antioxidant Potential of Jicama (Pachyrhizus erosus) Extract Fermented by Lactobacillus plantarum B1765

Jicama is a source of phenolic compounds that function as antioxidants. However, the presence of polyphenol oxidase and naturally bound phenolic compounds limits its antioxidant potential. Fermentation is one method to enhance the antioxidant potential of jicama. This study investigates the growth of lactic acid bacteria (LAB), pH, total titratable acidity (TTA), total phenolic content (TPC), and antioxidant activity of jicama extract (Pachyrhizus erosus) using L. plantarum B1765 as a starter culture which was fermented for 2, 12, 24, and 36 hours at 37°C. Total LAB is measured using the whole plate count technique, pH using a pH meter, TTA by acid-base titration, TPC using the Folin-Ciocalteu method, and antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method represented by IC50. The fermentation duration of jicama extract increased the growth of LAB to 108 CFU/mL and reached its optimum at 12 hours. However, reducing pH, increasing TTA to 0.223%, increasing TPC, and antioxidant activity still occur up to 36 hours of fermentation. Antioxidant activity was classified as vital. Duration of fermentation increased the growth of total LAB until the defined time, secreted β-glucosidase and inulinase enzymes, and also produced acid as their metabolism product, which hydrolyzed the glycoside bond and reduced pH, both act to free phenolic and increased antioxidant activity. This product has met Indonesian National Standards for beverage-fermented types and could be an antioxidant agent.

Enhanced lignin degradation by Irpex lacteus through expanded sterilization further improved the fermentation quality and microbial community during the silage preservation process

Traditional autoclaving, slow degradation rate and preservation of biomass treated by fungi are the main factors restricting biological treatment. In our previous studies, strains with high efficiency and selective lignin degradation ability were obtained. To further solve the limiting factors of biological treatment, this paper proposed a composite treatment technology, which could replace autoclaves for fungal treatment and improve the preservation and utilization of fungal-pretreated straw. The autoclaved and expanded buckwheat straw were, respectively, degraded by Irpex lacteus for 14 days (CIL, EIL), followed by ensiling of raw materials (CK) and biodegraded straw of CIL and EIL samples with Lactobacillus plantarum for different days, respectively (CP, CIP, EIP). An expansion led to lactic acid bacteria, mold, and yeast of the samples below the detection line, and aerobic bacteria was significantly reduced, indicating a positive sterilization effect. Expansion before I. lacteus significantly enhanced lignin selective degradation by about 6%, and the absolute content of natural detergent solute was about 5% higher than that of the CIL. Moreover, EIL decreased pH by producing higher organic acids. The combination treatment created favorable conditions for ensiling. During ensiling, EIP silage produced high lactic acid about 26.83 g/kg DM and the highest acetic acid about 22.35 g/kg DM, and the pH value could be stable at 4.50. Expansion before I. lacteus optimized the microbial community for ensiling, resulting in EIP silage co-dominated by Lactobacillus, Pediococcus and Weissella, whereas only Lactobacillus was always dominant in CP and CIP silage. Clavispora gradually replaced Irpex in EIP silage, which potentially promoted lactic acid bacteria growth and acetic acid production. In vitro gas production (IVGP) in EIL was increased by 30% relative to CK and was higher than 24% in CIL. The role of expansion was more significant after ensiling, the IVGP in EIP was increased by 22% relative to CP, while that in CIP silage was only increased by 9%. Silage of fungal-treated samples reduced methane emissions by 28% to 31%. The study demonstrated that expansion provides advantages for fungal colonization and delignification, and further improves the microbial community and fermentation quality for silage, enhancing the nutrition and utilization value. This has practical application value for scaling up biological treatment and preserving the fungal-treated lignocellulose.Graphical

Electromagnetic fields effects on microbial growth in cocoa fermentation: A controlled experimental approach using established growth models

Understanding the effects of electromagnetic fields is crucial in the fermentation of cocoa beans, since through precise control of fermentation conditions the sensory and nutritional properties of cocoa beans could be improved. This study aimed to evaluate the effect of oscillating magnetic fields (OMF) on the kinetic growth of the core microbial communities of the Collections Castro Naranjal (CCN 51) cocoa bean. The data was obtained by three different models: Gompertz, Baranyi, and Logistic. The cocoa beans were subjected to different OMF strengths ranging from 0 mT to 80 mT for 1 h using the Helmholtz coil electromagnetic device. The viable microbial populations of lactic acid bacteria (LAB), acetic acid bacteria (AAB), and yeast (Y) were quantified using the colony-forming unit (CFU) counting method. The logistic model appropriately described the growth of LAB and Y under magnetic field exposure. Whereas the Baranyi model was suitable for describing AAB growth. The microbial populations in cocoa beans exposed to magnetic fields showed lower (maximum specific growth rate (μmax), values than untreated controls, with AAB exhibiting the highest average growth rate value at 5 mT and Y having the lowest average maximum growth rate value at 80 mT. The lower maximum specific growth rates and longer lag phases when exposed to magnetic fields compared to controls demonstrate the influence of magnetic fields on microbial growth kinetics.

Production and evaluation of novel functional cream cottage cheese fortified with bovine colostrum and probiotic bacteria

AbstractNutrient-dense colostrum can be employed as a functional food ingredient. This work aimed to produce novel functional probiotic Cream cottage cheese (FPC) using probiotic (ABT) culture and bovine colostrum powder (BCP) at levels of 1, 2, and 3%. Physicochemical and functional properties (antioxidant activity, fatty acid profile, and antibacterial activity) were analyzed. The outcome revealed that hardness, cohesiveness, and gumminess were increased while springiness and chewiness were decreased for the treated cheeses. In FPC, medium-chain fatty acids were the predominant forms, followed by short- and long-chain fatty acids, polyunsaturated (PUFA), and small amounts of monounsaturated (MUFA). The antioxidant activity of all the cheese samples was significantly (P &lt; 0.05) increased by increasing the quantity of colostrum powder and lengthening storage time. Color parameters were influenced by enrichment with BCP, whether in fresh or stored samples. With the addition of BCP, the growth of lactic acid bacteria and Bifidobacteria was enhanced, whereas that of pathogenic bacteria, mold and yeast, and coliform groups was inhibited. Cheeses fortified with 2% BCP had significantly higher score values than those in the other treatments. Therefore, it could be concluded that cottage cheese fortified with 2% BCP has high nutritional value and health benefits.

Application of white wine lees for promoting lactic acid bacteria growth and malolactic fermentation in wine

In the context of ecological transition, the use of wine by-products for industrial applications is a major challenge. Wine lees, the second wine by-product in terms of quantity, represent a source of nutrients that can be used for stimulating the growth of microorganisms. Here, white wine lees were used as a stimulating agent for the growth of wine lactic acid bacteria (LAB) and to promote wine malolactic fermentation (MLF) driven out by Oenococcus oeni. By adding freeze-dried wine lees to wines under different conditions – including different wine lees at different concentrations and different O. oeni strains at various initial populations - it was observed that wine lees can enhance the growth of LAB and reduce the duration of MLF. The chemical composition of wines was also evaluated, proving that wine lees do not compromise the quality of the wines. In addition, wine lees did not seem to promote the growth of spoilage microorganisms like as Brettanomyces bruxellensis. Altogether, this work reports the possibility of recovering the lees of white wine to obtain a product favoring the MLF of red wines. More general, we propose a recycling strategy of wine by-products to obtain new products for winemaking.