Lactic Acid Bacteria Fermentation Research Articles

Functional Properties and Proximate Composition of Composite Flour from Banana (Musa acuminata x balbisiana var Cardaba C.) Sweetpotato (Ipomoea batatas Lam) and Glutinous Rice (Oryza sativa var glutinosa L.) Fermented with Lactobacillus plantarum (Orla-Jensen)-BIOTECH 1223

Composite flour is advantageous in countries where wheat cultivation is not possible, like in the Philippines. Hence, locally available crops like bananas, sweetpotato, and glutinous rice were processed into flour as an alternative to wheat flour. The application of lactic acid bacteria fermentation will modify the quality of the native flour, which can further improve its range of applications in baking. Thus, the study was conducted to evaluate the quality of the Lactobacillus plantarum (Orla-Jensen)- BIOTECH 1223-fermented composite flour from banana, sweetpotato, and glutinous rice flour. Ten treatments were generated using Simplex Centroid Design with different levels of the three independent variables. Response Surface Regression Analysis on the functional properties ranged from, water absorption capacity (115.20-155.32%), oil absorption capacity (54.88-70.32%), bulk density (0.80-0.90%), swelling capacity (1.16-1.86 mL0, and gelation property (2-6%) of the fermented composite flour. Proximate composition ranged from, 9.66-12.00% (moisture content), 1.84-5.87% (crude protein), crude fat (0.12-2.48%), and ash (0.0019-0.0273%). Physico-chemical (total soluble solids and titratable acidity) and proximate composition (moisture content and ash content) of the fermented composite flour from banana (FBF), sweetpotato (FSPF), and glutinous rice flour (FGRF) were significantly influenced by the lactic acid fermentation using Lactobacillus plantarum (Orla-Jensen)- BIOTECH 1223. Therefore, the fermentation of composite flour from banana (FBF), sweetpotato (FSPF), and glutinous rice flour (FGRF) can improve the functional properties and proximate composition of the composite flour.

Improving flavor, bioactivity, and changing metabolic profiles of goji juice by selected lactic acid bacteria fermentation

Lactic acid bacteria (LAB) have exhibited strain/species specificity for different food matrices. We investigated the impact of LAB fermentation on the flavor, chemical profile, and bioactivity of goji juice. The colony counts of five selected strains reached above 8.5 log CFU/mL. The fermentation increased the organic acids, decreased the sugars, and improved the sensory quality of goji juice. The majority of the strains had increased acetic acid, heptanoic acid, ethyl phenylacetate, and linalool levels. Specific strains suppressed α-glucosidase and pancreatic lipase activities and increased the antioxidant activities of fermented goji juice. Based on non-targeted metabolomics and activities, 23 important differential metabolites were screened among 453 metabolites. The quantification results showed that isoquercitrin and m-coumaric content varied among strains, reflecting the strain specificity in flavone and flavonol biosynthesis and phenylalanine, tyrosine, and tryptophan biosynthesis. These findings will provide useful information for fermented goji juice biochemistry research.

Evaluating the effect of lactic acid bacteria fermentation on quality, aroma, and metabolites of chickpea milk.

Legumes are an attractive choice for developing new products since their health benefits. Fermentation can effectively improve the quality of soymilk. This study evaluated the impact of Lactobacillus plantarum fermentation on the physicochemical parameters, vitamins, organic acids, aroma substances, and metabolites of chickpea milk. The lactic acid bacteria (LAB) fermentation improved the color, antioxidant properties, total phenolic content, total flavonoid content, lactic acid content, and vitamin B6 content of raw juice. In total, 77 aroma substances were identified in chickpea milk by headspace solid-phase microextraction with gas chromatography/mass spectrometry (HS-SPME-GC-MS); 43 of the 77 aroma substances increased after the LAB fermentation with a significant decrease in beany flavor content (p < 0.05), improving the flavor of the soymilk product. Also, a total of 218 metabolites were determined in chickpea milk using non-targeted metabolomics techniques, including 51 differentially metabolites (28 up-regulated and 23 down-regulated; p < 0.05). These metabolites participated in multiple metabolic pathways during the LAB fermentation, ultimately improving the functional and antioxidant properties of fermented soymilk. Overall, LAB fermentation can improve the flavor, nutritional, and functional value of chickpea milk accelerating its consumer acceptance and development as an animal milk alternative.

Improvement in color expression and antioxidant activity of strawberry juice fermented with lactic acid bacteria: A phenolic-based research

The aim of this study was to investigate the impact of lactic acid bacteria fermentation on color expression and antioxidant activity of strawberry juice from the perspective of phenolic components. The results showed that both Lactobacillus plantarum and Lactobacillus acidophilus were able to grow in strawberry juice, promote the consumption of rutin, (+)-catechin and pelargonidin-3-O-glucoside, and increase the content of gallic acid, protocatechuic acid, caffeic acid and p-coumaric acid compared to group control. Lower pH environment in fermented juice was likely to enhance the color performance of anthocyanins and increase its parameters a* and b*, making the juice appear orange color. In addition, the scavenging capacity of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and ferric reducing antioxidant capacity (FRAP) were improved and closely related to polyphenolic substances and strain’s metabolites in fermented juice.

Modification of sago flour by fermentation of Lactic Acid Bacteria

Indonesia is one of the countries with a high level of wheat consumption, where wheat flour is still imported. Therefore, food diversification need to be carried out and developed by utilizing local raw materials, such as sago. This study aims to determine the effect of fermentation time (0 hours, 24 hours, 48 hours, 72 hours, 96 hours, 120 hours) and the type of fermentation (Spontaneous Fermentation and Lactobacillus plantarum Fermentation) on several physicochemical properties of sago flour. This research was arranged in a completely randomized design (CRD) with factorial pattern, which consisted of factor A (type of fermentation) and factor B (length of fermentation). The treatments were analyzed using analysis of variance. When If the treatment was significantly different, it was continued with Duncan’s Test. The parameters observed were Total LAB, starch content, amylose content, and whiteness degree. The results showed that the type of fermentation Lactobacillus plantarum had a higher total bacterium (6.5474 Log CFU/ml) compared to total bacteria in spontaneous fermentation (5.2090 Log CFU/ml), the starch content in the fermentation of Lactobacillus plantarum (39.43%) was optimum at 48 hours. while spontaneous fermentation was at 96 hours (38.19%), the optimum amylose in Lactobacillus plantarum fermentation was at 24 hours (4.00%) while spontaneous fermentation was at 120 hours (4.15%), The white degree of fermentation of Lactobacillus plantarum was optimum at 72 hours (90.49) spontaneous fermentation at 48 hours (87.20).

Development of Probiotic-Fermented Black Mulberry (Morus nigra L.) Juice and Its Antioxidant Activity in C2C12 Cells

Black mulberry (Morus nigra L.) is considered a medicinal and food-homologous plant in China. An obstacle to its widespread use is that its annual season and shelf life are extremely short. In this paper, fermented black mulberry juice (FBMJ) was prepared with various probiotic strains, and response surface methodology was used to determine the optimum production conditions for achieving the maximum active substance content in the resulting product. The fermentation process increased levels of biological enzymes and total phenols in the resulting juice. When the ratios of the Lactobacillus inocula to the total inoculum were 27.96% for L. paracasei, 15.37% for L. casei, 16.64% for L. plantarum, and 5.12% for L. delbrueckii, the B. animalis subsp. lactis content reached 15.83%, the L. fermentum content reached 19.08%, and the superoxide dismutase (SOD) activity reached 310 U/g. To study the antioxidant characteristics of the juice, C2C12 cells were treated with H2O2 to induce oxidative stress and the cytoprotective activity of FBMJ was subsequently evaluated. After treatment with FBMJ for 24 h, cell viability was found to be protected under H2O2 exposure, while SOD and glutathione peroxidase (GSH-Px) levels were increased. The reactive oxygen species level and malondialdehyde content were also decreased. These results provide molecular evidence for the antioxidant effect of FBMJ and demonstrate that lactic acid bacteria fermentation has a positive effect on black mulberry juice (BMJ).

Investigations into the Usage of the Mineral Alginite Fermented with Lactobacillus Paracasei for Cosmetic Purposes

A remarkable interplay between the skin and the fermentation of lactic acid bacteria (LAB) occurs. The lactate and amino acids in the supernatant of this bacteria help to hydrate the skin. The fermentation broth of lactic acid bacteria, generally referred as "lactic acid bacteria ferment" according to International Nomenclature of Cosmetic Ingredients (INCI), has been used to make a variety of cosmetic components. The goal of this study was to evaluate new approaches to assess ferment filtrates (also known as cell-free fermentation broths) that could be used in cosmeceuticals. Despite years of research on the production of lactic acid, aesthetic evaluations have not yet been performed. First, the Lactobacillus paracasei strain NCAIM B.01525 was employed in our research. Furthermore, a fermentation broth was produced containing the Hungaricum mineral alginite and the impact of hydration on human skin tested. The influence of alginite on the fermentation of LAB was also examined. According to the results of the trials, although alginite might double and triple biomass and specific growth rates, respectively, it cannot facilitate hydration of the skin. These results might contribute to the development of more widely accessible, environmentally-friendly cosmetic components in the future.

New insights into immunomodulatory properties of lactic acid bacteria fermented herbal medicines.

The COVID-19 pandemic has brought more attention to the immune system, the body's defense against infectious diseases. The immunomodulatory ability of traditional herbal medicine has been confirmed through clinical trial research, and has obvious advantages over prescription drugs due to its high number of potential targets and low toxicity. The active compounds of herbal drugs primarily include polysaccharides, saponins, flavonoids, and phenolics and can be modified to produce new active compounds after lactic acid bacteria (LAB) fermentation. LAB, primary source of probiotics, can produce additional immunomodulatory metabolites such as exopolysaccharides, short-chain fatty acids, and bacteriocins. Moreover, several compounds from herbal medicines can promote the growth and production of LAB-based immune active metabolites. Thus, LAB-mediated fermentation of herbal medicines has become a novel strategy for regulating human immune responses. The current review discusses the immunomodulatory properties and active compounds of LAB fermented herbal drugs, the interaction between LAB and herbal medicines, and changes in immunoregulatory components that occur during fermentation. This study also discusses the mechanisms by which LAB-fermented herbal medicines regulate the immune response, including activation of the innate or adaptive immune system and the maintenance of intestinal immune homeostasis.

Co-fermentation of non-Saccharomyces yeasts with Lactiplantibacillus plantarum FST 1.7 for the production of non-alcoholic beer.

The non-alcoholic beer (NAB) sector has experienced steady growth in recent years, with breweries continuously seeking new ways to fulfil consumer demands. NAB can be produced by limited fermentation of non-Saccharomyces yeasts; however, beer produced in this manner is often critiqued for its sweet taste and wort-like off-flavours due to high levels of residual sugars and lack of flavour metabolites. The use of Lactobacillus in limited co-fermentation with non-Saccharomyces yeasts is a novel approach to produce NABs with varying flavour and aroma characteristics. In this study, lab-scale fermentations of Lachancea fermentati KBI 12.1 and Cyberlindnera subsufficiens C6.1 with Lactiplantibacillus plantarum FST 1.7 were performed and compared to a brewer's yeast, Saccharomyces cerevisiae WLP001. Fermentations were monitored for pH, TTA, extract reduction, alcohol production, and microbial cell count. The final beers were analysed for sugar and organic acid concentration, free amino nitrogen content (FAN), glycerol, and levels of volatile metabolites. The inability of the non-Saccharomyces yeasts to utilise maltotriose as an energy source resulted in extended fermentation times compared to S. cerevisiae WLP001. Co-fermentation of yeasts with lactic acid bacteria (LAB) resulted in a decreased pH, higher TTA and increased levels of lactic acid in the final beers. The overall acceptability of the NABs produced by co-fermentation was higher than or similar to that of the beers fermented with the yeasts alone, indicating that LAB fermentation did not negatively impact the sensory attributes of the beer. C. subsufficiens C6.1 and L. plantarum FST 1.7 NAB was characterised as fruity tasting with the significantly higher ester concentrations masking the wort-like flavours resulting from limited fermentation. NAB produced with L. fermentati KBI12.1 and L. plantarum FST1.7 had decreased levels of the undesirable volatile compound diacetyl and was described as 'fruity' and 'acidic', with the increased sourness masking the sweet, wort-like characteristics of the NAB. Moreover, this NAB was ranked as the most highly acceptable in the sensory evaluation. In conclusion, the limited co-fermentation of non-Saccharomyces yeasts with LAB is a promising strategy for the production of NAB.

Flavor production in fermented chayote inoculated with lactic acid bacteria strains: Genomics and metabolomics based analysis

In this study, genomics and metabolomics were combined to reveal possible bio-synthetic pathways of core flavor compounds in pickled chayote via lactic acid bacteria (LAB) fermentation. The Lactiplantibacillus plantarum, Levilactobacillus brevis, and Lacticaseibacillus paracasei were selected as core LAB strains with better flavor-producing ability for chayote fermentation. The genomic results showed L. plantarum contained the largest number of metabolism annotated genes, while L. brevis had the fewest. Besides, the largest number of volatile compounds was detected in chayote fermented by L. plantarum, followed by L. brevis and L. paracasei. Some unique odor-active compounds (aldehydes, esters, and alcohols) and taste-active compounds (amino acids and dipeptides) were produced by different LAB strains. Accordingly, phenylalanine metabolic pathway (M00360), amino acid metabolic decomposition pathway (the Ehrlich pathway) and the anabolic pathway (the Harris pathway), and fatty acid biosynthesis pathway (M00061) were the main biosynthesis pathway involved in the flavor formation via LAB fermentation.

The impact of different fermenting microbes on residual purine content in fermented lamb jerky following in vitro digestion

This is the first study to investigate the effect of different lactic acid bacteria fermentation methods on the purine content of mutton jerky and to examine the changes in purine in these fermented mutton jerky samples underan in vitro simulated digestive system to determine an efficient method for regulating exogenous purine intake. According to the analysis, x3-2b Lactobacillus plantarum and composite bacteria can directly reduce the purine content in fermented dried mutton and achieve the purpose of reducing the intake of purine. However, after simulated intestinal digestion, it was observed that the purine content of these different sample groups was significantly decreased, and 37x-3 Pediococcus pentosaceus had the better effect. It has been shown that the 37x-3 Pediococcus pentosaceus, Lactobacillus sake, and composite bacteria significantly enhance the degree to which residual purine is depleted in the large intestine during digestion. In sum, one potentially successful method of regulating exogenous purine consumption is the development of fermented meat products using certain beneficial bacteria as a starter.

Assessment of dynamic digestion fate of soy protein gel induced by lactic acid bacteria: A protein digestomics research

Food matrix plays an important role in regulating macronutrient digestibility. In this study, lactic acid bacteria (LAB)-fermented soy protein isolates (FSPIs) were prepared at a series of concentration (0.2%–5.0%, w/v). FSPIs with varied structures were obtained and tested in an in vitro dynamic gastrointestinal model. Then, a comparative digestomics research was conducted. Results demonstrated that the lowest gelation concentration of soy protein during LAB fermentation was 1.9% (w/v). The FSPIs showed structures ranging from a loosely stacked layer (non-gel, NG) to a denser gel network with varied hardness (weak gel, WG; medium gel, MG; and firm gel, FG) when the protein concentration was adjusted. The protein profile of gastrointestinal digestates demonstrated higher soluble protein and peptide in FSPI gels compared with FSPI-NG. FSPI gel digestates were predominantly promoted in glycinin G1 and the β-conglycinin α subunit. The change was dynamic between FSPI gels with varied structures. Weaker gels (FSPI-WG and FSPI-MG) facilitated the hydrolysis of glycinin G1/G4 and β-conglycinin α/β subunits at early and medium digestions (0–30 min). In comparison, the firmer gel (FSPI-FG) showed a postponed but more extensive promotion of the degradation of glycinin G1/G2 and β-conglycinin α subunits at the late digestion (180 min). The spatial structures of glycinin G1 and β-conglycinin α subunits demonstrated variations in seven and eight regions, respectively. Glycinin's region 6 (Y374–R388) and β-conglycinin's region 7 (L491–T519), which are located at the interior of the 3D structure, were the key regions contributing to the discrepancies.

Lactobacillus Strains for Vegetable Juice Fermentation-Quality and Health Aspects.

Vegetable juices are new carrier variants for beneficial bacteria, representing an alternative to dairy-fermented products, especially for vegan, strict vegetarian, or allergic consumers. The aim of this study was to characterize several Romanian native lactic acid bacteria (LAB) strains to select valuable nutritional and probiotic strains for vegetable juice fermentation. Nineteen LAB strains were analyzed for antibiotic susceptibility (disc-diffusion method), the presence of antibiotic resistance genes, the presence of functional genes. and the production of organic acids by HPLC. Antibiotic resistant strains were observed only with ampicillin (Amp10) and kanamycin (K30), 79% and 32%, respectively, with results partially confirmed by molecular analysis. Multiplex PCR revealed the presence of LBA1272, dltD, folP, agl, α-amy, malL, and ribA genes, related to stress resistance, starch metabolism, and production of vitamins, except for folK. HPLC analyses were performed on beet roots (SF), tomato (TM), and a mixture of carrots, celery, and beet (MTS) juices. High values of lactic acid were recorded in all cases of LAB fermentation (5034-14,176 µg/mL). The maximum values recorded for acetic acid did not exceed 2.5 mg/mL having a positive influence on the product's taste.

Effect of Lactobacillus plantarum Fermentation on Metabolites in Lotus Leaf Based on Ultra-High-Performance Liquid Chromatography–High-Resolution Mass Spectrometry

The lotus leaf is a raw material commonly used in slimming herbal products, but the deep processing technology is insufficient. Lactic acid bacteria (LAB) fermentation is an effective method to improve the efficacy of plant materials. In this study, ultra-high-performance liquid chromatography–high-resolution mass spectrometry (UHPLC–HR-MS) was used to explore the differential metabolites of a lotus leaf aqueous extract before and after fermentation. Information about the metabolites in the water extract of lotus leaves before and after fermentation was collected in positive- and negative-ion modes, and the metabolites identified before and after fermentation were screened by multivariate statistical analysis. A total of 91 different metabolites were obtained. They included flavonoids, alkaloids, phenylpropanoids, organic acids and derivatives, terpenoids, fatty acids and fatty acyls, phenols, amino acid derivatives and others. Compared with the metabolites’ levels before fermentation, the relative contents of 68 metabolites were upregulated after fermentation, and the relative contents of 23 metabolites were downregulated. A Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis identified 25 metabolic pathways, of which flavone and flavonol biosynthesis, citrate cycle and flavonoid biosynthesis were the main metabolic pathways. The results of this study can provide a basis for further research and the development of products containing lotus leaves fermented by LAB.

Effects of lactic acid bacteria fermentation on the phytochemicals content, taste and aroma of blended edible rose and shiitake beverage

In this research, five commercial lactic acid bacteria (LAB) strains were selected for the fermentation of blended edible rose and shiitake beverage for their frequent application and strong adaptability in plant-based beverages. The viable counts of all strains reached above 10.0 log CFU/mL in the blended beverage after fermentation (48 h). Meanwhile, higher contents of total phenols, total flavonoids, free amino acids, and flavor nucleotide as well as stronger antioxidant capacity were observed in the fermented samples than the control. The results of electronic tongue (E-tongue) analysis showed that LAB fermentation significantly (p＜0.05) lowered the signals of bitterness, astringency, aftertaste-A, and aftertaste-B, which ultimately improved the taste profiles of the fermented samples. Additionally, a total of 76 volatiles compounds were detected, among which alcohols were the dominant compounds. LAB fermentation also enriched the aroma complex of the fresh beverage, which resulted in new compounds, including 13 alcohols, 9 acids, 6 ketones, 4 esters, and 5 hydrocarbons in the fermented samples.

Effect of Lactobacillus plantarum and Lactobacillus acidophilus fermentation on antioxidant activity and metabolomic profiles of loquat juice

Nonalcoholic fermentation could improve the organoleptic quality and functionality of fruit juice, and lactic acid bacteria (LAB)-fermented fruit juice has been proven to be beneficial to human health. However, LAB exhibit strain specificity with different food matrices. In the present study, the effects of L. plantarum and L. acidophilus on the physicochemical characteristics, antioxidant activity and metabolomics of loquat juices were investigated. Both LAB strains fermentation could significantly enhance the antioxidant activity of loquat juice. L. acidophilus grows faster than L. plantarum in loquat juice, but L. plantarum fermentation more effectively increased the total flavonoid content. Nontargeted metabolomics analysis based on UHPLC-Q Exactive HF-X/MS were performed to reveal the different metabolic profiles between LAB fermentation. A total of 776 metabolites were identified and annotated. The significant differentially regulated metabolites were concentrated mainly in lipids and lipid-like molecules; organic acids and derivatives; amino acids, peptides, and analogs; phenolic compounds and terpenoids. The regulation of metabolites plays a very important role in the flavor reconstruction and functional improvement of loquat juices. In addition, the metabolic profiles between L. plantarum- and L. acidophilus-fermented loquat juices were different, and the application of cofermentation of these two strains may be considered in future studies.

Effects of lactic acid bacteria fermentation on chemical compounds, antioxidant capacities and hypoglycemic properties of pumpkin juice

The purpose of this research was to screen strains to ferment pumpkin juice with excellent flavor and biological activities by the comparison of 5 species of lactic acid bacteria (LAB) strains, namely Lacticaseibacillus casei (Lc), Lactiplantibacillus plantarum (Lp), Lactobacillus acidophilus (La), Lactobacillus helveticus (Lh) and Lacticaseibacillus paracasei (Lpc). The pumpkin juice inoculated with LAB was fermented at 37 °C for 48 h. Viable cell counts were all above 7.92 log CFU/mL, implicating that pumpkin juice was a favorable matrix for LAB. The contents of reducing sugars and total sugars contents obviously declined at the end of fermentation. LAB strains utilized mainly fructose, surcose and glucose for fermentation. Lpc fermented pumpkin juice showed the most abundant organic acid. Furthermore, the strongest DPPH and hydroxyl radical scavenging capacities were observed in Lp, La and Lh, which were positively associated with vanillic acid and sinapic acid contents. There were 30 new volatile compounds that appeared after fermentation, including 8 of ketones and alcohols, 5 esters and so on. The highest sensory scores could be found in La and Lh primarily due to their rich volatile compounds. LAB fermentation was beneficial to inhibiting α-glucosidase and α-amylase activities. In conclusion, La and Lh were more suitable to develop into a functional beverage with pleasant flavor.

Fermentation of Microalgal Biomass for Innovative Food Production.

Fermentation is an ancient method used worldwide to process and preserve food while enhancing its nutraceutical profile. Alga-based fermented products have recently been developed and tested due to growing interest in healthy sustainable diets, which demands the development of innovative practices in food production, operating for both human health and Earth sustainability. Algae, particularly microalgae such as Arthrospira platensis, Chlorella vulgaris, and Dunaliella salina, are already cultivated as sources of food due to their valuable compounds, including proteins, pigments, lipids, carotenoids, polyunsaturated fatty acids, steroids, and vitamins. Due to their nutritional composition, functional diversity, and flexible metabolism, microalgae represent good fermentation substrates for lactic acid bacteria (LAB) and yeasts. This review presents an overview of the scientific studies on microalga fermentation underlining microalgae’s properties and health benefits coupled with the advantages of LAB and yeast fermentation. The potential applications of and future perspectives on such functional foods are discussed.

Improving anti-hypertensive properties of plant-based alternatives to yogurt fortified with rice protein hydrolysate

In recent years, an increasing demand of plant-based yogurt-like products for partially replacing milk products was related to both health and ethical needs. The objective of this study was to improve the functionality of yogurt-like products relevant for hypertension, using fortification with protein hydrolysate and lactic acid bacteria (LAB) fermentation of soy and Job’s tears beverages. Broken rice was hydrolysed by protease enzymes. Plant-based beverages and yogurt-like products with and without rice protein hydrolysate were prepared by LAB fermentation and evaluated by in-vitro assays for inhibition of free radical scavenging and angiotensin-converting enzyme (ACE) activity. Biochemical changes caused by lactic acid bacteria metabolism were characterized using chemical analysis and 1H NMR. The rice protein hydrolysate obtained using Alcalase® at pH 7.0 for 2 h at 60 °C showed the highest antioxidant activity and ACE inhibition. The ACE inhibition increased by 19.52% and 34.13% in Job’s tears and soy yogurt-like products with hydrolysate, respectively. A strongly significant correlation (R2 = 0.84) between o-phthalic dicarboxaldehyde (OPA) peptides and ACE inhibition was observed. These results indicated the promise of hydrolysate and LAB fermentation as a functional ingredient and process, respectively, for the food industry.

The impact of alternative nitrogen sources on the growth and viability of Lactobacillus delbrueckii ssp. bulgaricus.

In this study, we developed and optimized a growth medium using various nitrogen sources for the cultivation of Lactobacillus delbrueckii ssp. bulgaricus, a probiotic and essential dairy starter culture. The composition of de Man, Rogosa, and Sharpe (MRS) culture medium was modified, and the nitrogen content was replaced by alternative nitrogen sources X-Seed Nucleo Max, X-Seed KAT, and X-Seed Carbo Max (Ohly GmbH) in various blends of 5 and 10 g/L. Results showed that bacterial growth was significantly higher when the nitrogen source blend of 10 g/L of KAT and 10 g/L of Carbo Max [KCMax (10/10)] was used. The optical densities of the Lb. bulgaricus strains were significantly higher in the KCMax (10/10) medium than in the MRS medium. There was no significance in bacterial counts for both the MRS and the KCMax (10/10) medium, and all bacterial counts were estimated at 8 log cfu/mL. The buffering capacity of the KCMax (10/10) medium was also tested and supplemented with l-histidine and was significantly higher than that of the MRS control medium. KCMax (10/10) also supported the freeze-stability and viability of the Lb.bulgaricus cells during freezing and freeze-drying operations. Our results suggest that the alternative nitrogen sources X-Seed Nucleo Max, X-Seed KAT and X-Seed Carbo Max can substantially support the growth of lactic acid bacteria as demonstrated with Lb. bulgaricus. These alternative nitrogen sources could thus be recommended for lactic acid bacteria fermentation and for the cultivation of dairy starter cultures.