A new plant-based probiotic from juá: Source of phenolics, fibers and antioxidant properties.

The objective of this study was to evaluate the viability of juá pulp for fermentation by monoculture L. casei (Lc - 01) and L. acidophilus (La - 05) and co-culture (25 and 37 °C) for 72 h. Viable strain values (> 7 log CFU/g), pH reduction (below 3.7), fructose and glucose and increased of lactic acid showed that the pulp of juá served as a good matrix for fermentation. Catechin, epicatechin, epigallocatechin procyanidin B1, and gallic acid were the main phenolics that contributed to antioxidant activity. Fermentation by mono or co-culture increased or reduced the content of phenolics and antioxidant activity. Results showed that culture, time and temperature have effects in the fermentation of juá pulp. The co-cultivation of La - 05 + Lc - 01 contributed to improving the bioaccessibility of gallic acid (72.9%) of the jua pulp. Finding indicate juá pulp as a promising substrate to obtaining a new probiotic plant-based fermented beverage.

γ-Aminobutyric Acid (GABA)-enriched Hemp Milk by Solid-state Co-fermentation and Germination Bioprocesses.

This study introduces the concept of developing a functional hemp drink enriched with γ-Aminobutyric acid (GABA) to enhance its nutritional value and functional properties utilizing Solid-State (SSF) co-Fermentation by Lactobacillus casei and Bacillus subtilis and germination bioprocesses. Bioprocesses may offer an alternative solution to challenges in hemp milk, such as product instability and the use of additives. Notably, the hemp milk produced through the germination for three days or co-fermentation processes yielded the highest GABA content of 79.84 and 102.45 mg/100 mL, respectively, compared to the untreated milk. These bioactive milk samples exhibited higher zeta potential and soluble protein content and also reduced solid particle sedimentation and droplet sizes (D4,3 and D3,2) compared to the untreated milk. Furthermore, the peptide, total phenolic content, and antioxidant activity of the produced GABA-enriched kinds of milk surpassed those of the untreated milk. Overall, the SSF and germination processes present a promising alternative for producing stable milk analogs with enhanced health-boosting properties.

Growth Behavior of Probiotic Lactobacillus casei 01 in Tiger Nut Milk Prepared with Milk By-Products.

<b>Background and Objective:</b> Different researches have been achieved on non-dairy products as an alternative to dairy products. The interest in tiger nut tubers has considerably increase in recent years due to its nutritional and health benefits. Fermented drinks of non-dairy origin play an important role in diets worldwide. The aim of this study was to investigate the growth behavior and viability of <i>L. casei</i>-01 in tiger nut milk made with milk permeate or cheese whey as an extraction medium. <b>Materials and Methods:</b> Tiger nut milks were prepared using tiger nut tubers at ratios 1 to 3 (w/v) of water, milk permeate or cheese whey as extract media. Tiger nut milks and Skimmed milk were inoculated with <i>L. casei</i>-01 at 2%. The Titratable Acidity (TA) and <i>L. casei</i>-01 were determined during fermentation at 37°C for 8 hrs as well as during cold storage at 4°C for 20 days. <b>Results:</b> Results showed that the substitutions of water with permeate or whey led to the change of chemical composition of tiger nut milk. Fermented permeate or whey-tiger nut milk significantly had higher rate of titratable acidity development during fermentation or during cold storage as compared with fermented water-tiger nut milk or skimmed milk. The total viable counts of <i>L. casei</i>-01 were the highest in fermented whey-tiger nut milk after 10 days. <b>Conclusion:</b> <i>Lactobacillus casei</i>-01 can grow with high viability in permeate or whey-tiger milk.

Biosafety devices to control the spread of potentially contaminated dispersion particles. New associated strategies for health environments.

Dental procedures produce a large amount of spatter and aerosols that create concern for the transmission of airborne diseases, such as Covid-19. This study established a methodology with the objective of evaluating new associated strategies to reduce the risk of cross-transmission in a health environment by simulating spread of potentially contaminated dispersion particles (PCDP) in the environment. This crossover study, was conducted in a school clinic environment (4 clinics containing 12 dental chairs each). As a positive control group (without barriers), 12 professionals activated at the same time the turbine of dental drill, for one minute, with a bacterial solution (Lactobacillus casei Shirota, 1.5x108 CFU/mL), which had been added in the cooling reservoir of the dental equipment. In the experimental groups, the professionals made use of; a) an individual biosafety barrier in dentistry (IBBD) which consists of a metal support covered by a disposable PVC film barrier; b) a Mobile Unit of Disinfection by Ultraviolet-C, consisting of 8 UV lamps-C of 95W, of 304µW/cm2 of irradiance each, connected for 15 minutes (UV-C) and; c) the association between the two methods (IBBD + UV-C). In each clinic, 56 Petri dishes containing MRS agar were positioned on the lamps, benches and on the floor. In addition, plates were placed prior to each test (negative control group) and plates were also placed in the corridor that connects the four clinics. In the groups without barrier and IBBD + UV-C the passive air microorganisms in Petri dishes was also evaluated at times of 30, 60, 90 and 120 minutes after the end of the dental's drill activation. The mean (standard deviation) of CFU of L. casei Shirota for the positive control group was 3905 (1521), while in the experimental groups the mean using the IBBD was 940 (466) CFU, establishing a reduction on average, of 75% (p<0.0001). For the UV-C group, the mean was 260 (309) CFU and the association of the use of IBBD + UV-C promoted an overall average count of 152 (257) CFU, establishing a reduction on average of 93% and 96%, respectively (p<0.0001). Considering these results and the study model used, the individual biosafety barrier associated with UV-C technology showed to be efficient strategies to reduce the dispersion of bioaerosols generated in an environment with high rate of PCDP generation and may be an alternative for the improvement of biosafety in different healthy environment.

Woodfordia fruticosa extract supplementation stimulates the growth of Lacticaseibacillus casei and Lacticaseibacillus rhamnosus with adapted intracellular and extracellular metabolite pool.

AIM: To investigate the effect of Woodfordia fruticosa extract (WfE) on two probiotic bacteria: Lacticaseibacillus casei and Lacticaseibacillus rhamnosus. METHODS AND RESULTS: WfE supplementation at 0·5 and 1 mg ml-1 stimulated probiotic growth (P < 0·05), enhanced adhesion to CaCO2 cells (P < 0·05) while inhibiting foodborne pathogens Escherichia coli and Staphylococcus aureus (P < 0·05). 1 H-NMR based metabolomic studies indicated higher glucose : lactate and glucose : acetate in the extracellular matrix with significant variation (P < 0·05) in intracellular concentrations of lactate, acetate, glutamate, dimethylamine, phenylalanine, branched-chain amino acids and total cellular lipid composition. Fatty acid methyl ester analysis showed a chemical shift from saturated to unsaturated lipids with WfE supplementation. PCA plots indicated clear discrimination between test groups, highlighting variation in metabolite pool in response to WfE supplementation. CONCLUSION: Phytonutrient-rich WfE exhibited prebiotic-like attributes, and probiotic bacteria showed altered metabolite pools as an adaptive mechanism. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report providing insights into the prebiotic-like activity of WfE on gut representative probiotics. The extended metabolomic studies shed light on the positive interaction between phytonutrients and beneficial bacteria that possibly help them to adapt to a phytonutrient-rich WfE environment. WfE with potential prebiotic attributes can be used in the development of novel synbiotic functional products targeting gut microbial modulation to improve health.

Impact of encapsulating probiotics with cocoa powder on the viability of probiotics during chocolate processing, storage, and in vitro gastrointestinal digestion.

Chocolates can be formulated as a functional food via enrichment with probiotics. However, the added probiotics must overcome the challenges of processing and storage conditions and the harsh gastrointestinal environment. The study aimed to overcome these challenges using two different formulations of cocoa powder as alternative encapsulants along with Na-alginate (A1 ) and Na-alginate and fructooligosaccharides (A2 ). Seven different probiotic strains were encapsulated individually using the new formulations and viabilities of these encapsulated probiotics were assessed prior to and after they were added to chocolates. The highest achieved encapsulation efficiencies were 93.40% for formulation A1 (with Lactobacillus casei) and 95.36% for formulation A2 (with Lactobacillus acidophilus La5). The encapsulated probiotics with the new formulations maintained higher viability than the recommended therapeutic level (107 colony forming unit [CFU]/g) for up to 180 and 120 days of storage at 4 and 25 °C, respectively. The tested encapsulants improved probiotics survival when subjected to thermal stress and maintained about 9.0 Logs CFU/g at 60 °C. Additionally, the viable numbers of probiotics in fortified chocolates showed higher than 7 Logs CFU/g after 90 days of storage at 25 °C. Both formulations exhibited significantly (P < 0.05) high survivability of probiotics (8.0 Logs CFU/g) during the in vitro gastrointestinal digestion. This study demonstrated that cocoa powder along with Na-alginate and FOS has the potential to be used as a probiotic encapsulating material, and chocolates could be an excellent carrier for the development of healthy probiotic chocolate products. PRACTICAL APPLICATION: The introduction of cocoa powder as an effective encapsulating agent to deliver probiotics could help the chocolate industry to develop healthy and attractive functional snacks for health-conscious consumers.

Microencapsulation of Lactobacillus casei and Lactobacillus rhamnosus in pectin and pectin-inulin microgel particles: Effect on bacterial survival under storage conditions.

The main objective of the research was to evaluate the performance of synbiotic delivery systems using pectin microgels on the protection of two probiotic strains (Lactobacillus casei ATCC 393 and Lactobacillus rhamnosus strain GG [ATCC 53103]) to simulated gastrointestinal digestion (GD) and storage conditions (4 ± 1 °C) in a 42 days trial. Microgel particles were prepared by ionotropic gelation method and three variables were evaluated: incubation time (24 and 48 h), free vs encapsulated cells, and presence or absence of prebiotic (commercial and Jerusalem artichoke inulin). Results demonstrated an encapsulation efficiency of 96 ± 4% into particles with a mean diameter between 56 and 118 µm. The viability of encapsulated cells after 42 days storage stayed above 7 log units, being encapsulated cells in pectin-inulin microgels more resistant to GD compared to non-encapsulated cells or without prebiotics. In all cases incubation time influenced the strains' survival.

The effect of lactic acid fermentation with different bacterial strains on the chemical composition, immunoreactive properties, and sensory quality of sweet buttermilk.

This paper describes the successful development of new low-immunoreactive buttermilk (BM)-based formulations which were fermented with 31 lactic acid bacteria (LAB) and Bifidobacterium strains. The aim of this study was to create a new formula, which can serve as potential candidates for the immunotherapy of allergy. Preparations were tested for their content of biologically active compounds, such as proteins, peptides, phospholipids, and short-chain fatty acids (SCFA), as well as for the survivability of LAB and sensory quality. The results showed that the BM was a matrix rich in nutritional components and displayed higher than expected susceptibility to the reduction of protein IgE-immunoreactivity (to 98%) and high bacterial-protecting capacity. The overall sensory quality of examined products was influenced by the profile of SCFA and free peptides, but two formulations fermented with Lactobacillus delbrueckii ssp. bulgaricus-151 and Lactobacillus casei-LcY were the most advantageous with desirable sensory, immunoreactive, and biochemical properties.

Application of qPCR for multicopper oxidase gene (MCO) in biogenic amines degradation by Lactobacillus casei.

Degradation of undesirable biogenic amines (BAs) in foodstuffs by microorganisms is considered one of the most effective ways of eliminating their toxicity. In this study, we designed two sets of primers for the detection and quantification of the multicopper oxidase gene (MCO), which encodes an enzyme involved in BAs degradation, and endogenous (glyceraldehyde-3-phosphate dehydrogenase) gene (GAPDH) in Lactobacillus casei group by real-time PCR (qPCR). We tested 15 Lactobacillus strains in the screening assays (thus, MCO gene possessing assay (PCR) and monitoring of BAs degradation by HPLC-UV), in which Lactobacillus casei CCDM 198 exhibited the best degradation abilities. For this strain, we monitored the expression of the target gene (MCO) in time (qPCR), the effect of redox treatments (cysteine, ascorbic acid) on the expression of the gene, and the ability to degrade BAs not only in a modified MRS medium (MRS/2) but also in a real food sample (milk). Moreover, decarboxylase activity (ability to form BAs) of this strain was excluded. According to the results, CCDM 198 significantly (P < 0.05) reduced BAs (putrescine, histamine, tyramine, cadaverine), up to 25% decline in 48 h. The highest level of relative expression of MCO (5.21 ± 0.14) was achieved in MRS/2 media with cysteine.

Applicability of potentially probiotic Lactobacillus casei in low-fat Italian type salami with added fructooligosaccharides: in vitro screening and technological evaluation.

The aim was to evaluate the use of Lactobacillus casei strains in the fermentation process of low-fat Italian type salami with fructooligosaccharides (FOS). A screening using probiotic strains was performed at pH 5.5, 5.0 and 4.5 and incubation temperatures of 15 and 25 °C. Lactobacillus casei SJRP66 and Lactobacillus casei SJRP169 were selected and added to the low-fat fermented sausage - C (control), FOS (25% reduced fat with 2% FOS), FOS_66 (25% reduced fat with 2% FOS and L.casei SJRP 66) and FOS_169 (25% reduced fat with 2% FOS and L.casei SJRP 169). The evaluation included pH, moisture, lactic acid bacteria count, probiotic count, weight loss, instrumental color, TBARS and texture parameters. FOS_66 and FOS_169 presented a good probiotic count (8 log CFU/g) and similar technological behavior to the control. The addition of the probiotic showed no effect on lipid oxidation and * value. These strains of probiotic showed promising properties for applications in low-fat Italian type salami with healthier appeal.

The probiotic L. casei LC-XCAL™ improves metabolic health in a diet-induced obesity mouse model without altering the microbiome.

Chronic low-grade inflammation associated with obesity may be a target for improvement of metabolic health. Some exopolysaccharide (EPS)-producing bacteria have been shown to have anti-inflammatory effects in gastrointestinal inflammatory conditions. However, evidence for the role of EPS-producing probiotics in the management of obesity and associated conditions is scarce and the role of the microbiota is unclear. In this study, two probiotic candidates were screened for their effects on metabolic health using the diet-induced obesity (DIO) mouse model. Mice fed a high-fat diet supplemented with the anti-inflammatory, EPS-producing strain L. caseiLC-XCAL™ showed significantly reduced hepatic triglycerides, hepatic total cholesterol, and fat pad weight compared to those fed a high-fat diet alone, likely as a result of reduced energy absorption from food. 16-S rRNA amplicon analysis of the fecal microbiota of these mice indicated that the altered metabolic phenotype as a result of the L. casei LC-XCAL strain administration was not associated with an overall change in the composition or inferred functional capacity of the fecal microbiota despite some abundance changes in individual taxa and functions. These findings provide evidence that specific microbial strategies can improve metabolic health independent of the microbiome and reinforce the importance of carefully selecting the most appropriate strain for specific indications by thorough screening programmes.

Effect of Various Bulk Sweeteners on the Survivability of Lactobacillus casei 431 in Milk Chocolate: Rheological and Sensory Properties Analysis.

BACKGROUND: Probiotics are the most widely consumed functional food. Consumers demand the production of foods also in low-calorie forms. OBJECTIVE: In this study, Lactobacillus casei 431 and various sweeteners were used in milk chocolate as probiotic and bulking agents, respectively. METHODS: Samples were prepared by using sucrose or optimum polyols combination. Chocolate samples were stored at two temperatures (4°C and 20°C) for 180 days and the viability of probiotic cells was controlled with the purpose of specifying the presented storage temperature. RESULTS: The highest probiotic viability was determined in the samples produced with sucrose and stored at 4°C. The cell counts were retained at the functional amount after maintenance for 6 months. Probiotic sucrose-free chocolate was more viscous than control chocolate, although displayed satisfactory sensory attributes. CONCLUSION: As a result, the sugared and sugar-free probiotic milk chocolates could be stored at room temperature. Due to the acceptable number of probiotic cells, the sucrose-free chocolates containing probiotics were considered as functional foods.

Stable Colonization of Orally Administered Lactobacillus casei SY13 Alters the Gut Microbiota.

The gut microbiota plays an important role in intestinal health. Probiotics such as Lactobacillus are known to regulate gut microbes and prevent diseases. However, most of them are unable to colonize their stability in hosts' intestinal tracts. In this study, we investigated the ability of Lactobacillus casei SY13 (SY13) to colonize the intestinal tract of BALB/c mice, after its oral administration for a short-term (once for a day) and long-term (once daily for 27 days) duration. Furthermore, we also evaluated the influence of its administration on the gut microbial structure and diversity in mice. Male BALB/c mice were gavaged with 108 colony-forming units (CFU) of SY13, and TaqMan-MGB probe and Illumina MiSeq sequencing were performed to assess the colonization ability and bacterial community structure in the cecum contents. The results showed that long-term treatment with SY13 enhanced its ability to form a colony in the intestine tract in contrast to the short-term treatment group, whose colony was retained for only 3 days. Oral administration of SY13 also significantly enhanced the gut microbial diversity. Short-term treatment with SY13 (SSY13) elevated Firmicutes and diminished Bacteroidetes phyla compared with long-term treatment (LSY13) and controls. The findings laid the foundation for the study of probiotic colonization ability and improvement of microbiota for the prevention of gut diseases.

Feasibility of exhausted sugar beet pulp as raw material for lactic acid production.

BACKGROUND: Exhausted sugar beet pulp pellets (ESBPP), a sugar industry by-product generated after sugar extraction in the sugar production process, have been used as a raw material for lactic acid (LA) production via hydrolysis and fermentation by Lactobacillus casei. To design a more cost-effective process, simultaneous saccharification and fermentation (SSF) of ESBPP is proposed in the present study. The effects of pH control, nutrient supplementation and solid addition in fed-batch SSF on lactic acid production were investigated. RESULTS: The highest LA concentration (26.88 g L-1 ) was reached in fed-batch SSF at a solid/liquid loading of 0.2 g mL-1 , with pH control (by adding 30 g L-1 CaCO3 to the medium) and nutrient supplementation (by adding 20 mL of MRS medium per 100 mL of buffer). Under these conditions, a maximum productivity of 0.63 g L-1 h-1 was achieved, which is 2.7 times higher than that attained in the control experiment (SSF inoculated at time 0 h). However, a slightly lower LA yield was obtained, revealing the need of an increasing dose of enzymes at high solid loading SSF. CONCLUSION: An efficient fed-batch SSF strategy with pH control and MRS supplementation is described in the present study, attaining higher LA productivity compared to separate hydrolysis and fermentation and SSF. © 2020 Society of Chemical Industry.

Synbiotic edible film from konjac glucomannan composed of Lactobacillus casei-01® and Orafti®GR, and its application as coating on bread buns.

BACKGROUND: Konjac glucomannan-based edible films formulated with Lactobacillus casei-01® and chicory-derived inulin Orafti®GR were studied for their properties, stability, and application as coatings on bread buns. RESULTS: Thickness and transparency were variable and dependent on the formulations. Alterations in color properties of all supplemented films were unnoticeable by unaided human eyes, with ΔE less than 3. Lactobacillus casei-01® and Orafti®GR were associated with higher water solubility of the films. Lactobacillus casei-01® decreased the water vapor permeability of the films while Orafti®GR promoted it. The mechanical properties in all combinations remained unchanged, although those with Orafti®GR showed profoundly reduced tensile strength. Scanning electron micrographs and Fourier transform infrared spectra of the films confirmed good homogeneity and intermolecular attraction between the prebiotic and konjac glucomannan. Cell viability in the films stored at room temperature decreased sharply, becoming less than the minimum recommended level after day 4, while viable L. casei-01® in coatings on bread buns gradually decreased, with a reduction of ca. 2 log colony-forming units (CFU) portion-1 over the 7 day storage period at room temperature. CONCLUSION: The synbiotic film and coating developed in this study are a relatively simple strategy for incorporating L. casei-01® and Orafti®GR into bread buns, which are short shelf-life foods. Bread buns with synbiotic coating could diversify functional food choices. Pretreatment, together with other technologies, is required to maintain a desirable number of active probiotic cells for longer. © 2020 Society of Chemical Industry.

Is there an impact of the dairy matrix on the survival of Lactobacillus casei Lc-1 during shelf life and simulated gastrointestinal conditions?

BACKGROUND: The selection of the food matrix to be used as a vehicle for a probiotic culture is important because its chemical composition and physicochemical characteristics can affect probiotic survival during the shelf-life of the product and under simulated gastrointestinal conditions (SGIC). The present study aimed to evaluate the influence of the dairy matrix (chocolate fermented milk beverage, chocolate flan or passion fruit flan) on the survival of Lactobacillus casei Lc-1 during refrigerated storage (4 °C for 21 days) and SGIC. RESULTS: Chocolate fermented milk beverage and chocolate and passion fruit flans could be considered as matrices for the incorporation of L. casei, providing suitable counts (6.38-7.84 log cfu g-1 ) during storage. The type of matrix had an impact on the inicial probiotic counts in the products and on the probiotic resistance to the SGIC. The chocolate fermented milk beverage presented higher initial probiotic counts (7.72 versus 6.65-7.28 log cfu g-1 ). The higher pH (5.3-6.8), solid matrix and increased fat content (65.0-72.9 g 100 g-1 ) contributed to the higher resistance to the SGIC of the chocolate and passion fruit flans, allowing recovery of viability during the enteric phase (increases of 1-1.5 log cycles). CONCLUSION: The type of dairy matrix has an impact on the inicial probiotic counts in the products and on the probiotic resistance to the SGIC. Chocolate and passion fruit flans proved to be more suitable options than chocolate fermented milk beverage for the incorporation of Lactobacillus casei Lc-1. © 2019 Society of Chemical Industry.

Bioactive properties of probiotic set-yogurt supplemented with Siraitia grosvenorii fruit extract.

Siraitia grosvenorii fruit (SGF) has been used as a natural sweetener and traditional medicine in China for more than two centuries. This study evaluated the effect of SGF extract supplementation (0.5%, 1%, and 2%) on the chemical, microbial and sensory properties of probiotic yogurt. The antioxidant, angiotensin-converting-enzyme inhibitory (ACE-I) and antibacterial bioactivities were determined. SGF extract supplementation improved some of the chemical and physicochemical characteristics. Probiotic yogurt with the fruit extract had significantly more Lactobacillus casei and Lactobacillus bulgaricus, whereas there was no significant effect on the number of Streptococcus thermophiles. The bioactivities were significantly increased by SGF extract supplementation. Probiotic yogurt with 2% SGF extract showed the highest antioxidant, ACE-I, and antibacterial activities, whereas the one with 1% SGF extract conferred the highest sensory attributes score. Overall, SGF extract offers a promising option as a dietary supplement to produce novel dairy products that have high nutritional and bioactivity values.

Using nitrous acid-modified de Man, Rogosa, and Sharpe medium to selectively isolate and culture lactic acid bacteria from dairy foods.

Nitrous acid was used to modify traditional de Man, Rogosa, Sharpe medium to evaluate whether the addition of sodium nitrite to MRS medium could improve the rate of growth and density of various lactic acid bacteria and nontarget species. Yogurt and Cheddar cheese were inoculated with individual bacterial species followed by the recovery and enumeration of the species using the pour plate method to compare the sensitivity between nitrous acid-modified MRS (mMRS) and traditional MRS. Lactobacillus delbrueckii ssp. bulgaricus were recovered at significantly higher counts from cheese in nitrous acid mMRS than MRS, whereas no significant difference was observed for other species and food systems. Growth curves were also generated for multiple lactic acid bacteria as well as nonstarters in both mMRS and MRS to measure the selectivity of nitrous acid mMRS. The selectivity evaluation of nitrous acid mMRS demonstrated that 5 of the tested lactic acid bacterial species (Bifidobacterium longum, Streptococcus salivarius, Lactococcus lactis, Lactobacillus acidophilus, and Lactobacillus delbrueckii ssp. bulgaricus) grew to significantly higher densities more rapidly in mMRS broth than in traditional MRS. Nontarget bacteria Enterococcus faecalis and Bacillus cereus revealed a more prolific growth rate and higher optical density readings in traditional MRS compared with mMRS. It was determined that nitrous acid mMRS is a viable alternative medium for culturing selected lactic acid bacteria, and offers an improved formulation of MRS for use in standard evaluation methods and optimization of probiotic and other dairy cultures.

Comparison of Lactic Acid Production by L. casei in Batch, Fed-batch and Continuous Cultivation, Testing the use of Feather Hydrolysate as a Complex Nitrogen Source

Abstract A comprehensive comparison of the main fermentation parameters, productivity, yield and final L-lactic acid concentration, obtained through batch, fed-batch and continuous cultivations using Lactobacillus casei CCDM 198 and a model cultivation medium was carried out. Using this data, a pulse-feed fed-batch process was established for testing chicken feather hydrolysate as a replacement for all complex nitrogen sources (yeast and beef extracts and peptone) in the medium. As comparably high values of productivity (about 4.0 g/L/h) and yield (about 98 %) were reached under all cultivation conditions, the maximum final L-lactic acid concentration (116.5 g/L), as achieved through pulse-feed fed-batch fermentation, was chosen as the most important criterion for process selection. Fed-batch cultivation with chicken feather hydrolysate as both a complex nitrogen source and a neutralizing agent for maintaining constant culture pH yielded half the concentration of L-lactic acid compared to the model medium. We demonstrate here that chicken feather hydrolysate has potential for use in the production of L-lactic acid but its utilization requires further optimization

Survival of microencapsulated Lactobacillus casei (prepared by vibration technology) in fruit juice during cold storage

Background: Foods including probiotics are considered "functional foods." As an alternative to dairy products, we investigated the behavior of Lactobacillus casei when exposed to low-pH fruit juice. Juices of fruits such as pineapple, raspberry, and orange were assessed. Free and microencapsulated forms of L. casei were compared, and the viability of the probiotic was evaluated under storage at 4°C for 28 d. Microbiological analyses were carried out to ensure a safe and healthy product for consumers who look for foods with probiotics from sources other than dairy. Results: Low pH affected L. casei survival during storage depending on the type of fruit juice. In the case of pineapple juice, some microcapsules were broken, but microcapsules recovered at the end of the storage period had 100% viability (2.3 × 107 CFU/g spheres). In the case of orange juice, more than 91% viability (5.5 × 106 CFU/g spheres) was found. In raspberry juice, viability decreased rapidly, disappearing at the end of the storage period, which was caused by the absorption of high concentrations of anthocyanin inside microcapsules more than low pH. Conclusion: Low pH affected the survival of L. casei under refrigeration; even when they were microencapsulated, acidic conditions impacted their viability. Although pH affects viability, its value is very sensitive and will depend on the type of fruit juice and its composition. Some fruit juices contain compounds used as substrates for Lactobacillus and other compounds with antimicrobial effects.