Freeze-dried Cultures Research Articles

Influence of Freeze-Dried Yeast Starter Cultures on Volatile Compounds of Tchapalo, a Traditional Sorghum Beer from Côte d’Ivoire

The production of the Ivorian sorghum beer known as tchapalo remains more or less an empirical process. The use of starter cultures was therefore suggested as the appropriate approach to alleviate the problems of variations in organoleptic quality and microbiological stability. In this study, we evaluated the capacity of S. cerevisiae and C. tropicalis to produce sorghum beer as freeze-dried starter in mixed or pure cultures. Beers produced with mixed freeze-dried cultures of S. cerevisiae F12-7 and C. tropicalis C0-7 showed residual sugars and ethanol contents similar to beers obtained with S. cerevisiae F12-7 pure culture, but the total sum of organic acids analyzed was the highest with the mixed culture (15.71 g/L). Higher alcohols were quantitatively the largest group of volatile compounds detected in beers. Among these compounds, 2-phenyl ethanol, a higher alcohol that plays an important role in beer flavor, was highly produced with the mixed culture (10,174.8 µg/L) than with the pure culture (8749.9 µg/L).

Effectiveness of convective drying to conserve indigenous yeasts with high volatile profile isolated from algerian fermented raw bovine milk (Rayeb)

Yeasts Candida tropicalis, Yarrowia lipolytica, Wickerhamomyces anomalus, Issatchenkia orientalis, Kluyveromyces marxianus, Saprochaete suaveolens and Trichosporon coremiiforme were isolated and identified by physiological, biochemical tests with API 20C AUX system and molecular methods by restriction fragment analysis of PCR-amplified 28S-rRNA from Algerian fermented raw bovine milk (Rayeb). Selected yeasts S. suaveolens, I. orientalis, K. marxianus and W. anomalus produced esters and higher esters which can exert a pertinent influence on the sensory characteristics of Rayeb. Viability of S. suaveolens and W. anomalus using three methods of drying (freeze-drying, convective drying, and spray-drying) and during 4 months of storage at 4 °C and 25 °C in the darkness was studied. Immediately after each drying method, high survival was obtained using freeze-drying followed by convective drying in rice cakes and spray-drying respectively. During storage at 4 °C, convective drying provided better survival of yeast cultures of S. suaveolens and W. anomalus than freeze-drying. At 25 °C of storage, convective and freeze-dried yeast cultures showed no significant loss of viable cells up to 2 months of storage. Spray-dried yeast cultures had the greatest loss of viable count during the 3 months of storage at 25 °C.

Эффективность пробиотиков в лечении и профилактике стоматологических заболеваний

Aim of our study was to study the preventive and therapeutic effect of microbial products, including dry and freeze-dried live cultures of lactobacillus. The article presents the results of comparative evaluation of the dynamics of clinical data in the prevention in 164 adolescents aged 14 to 18 years, and in the treatment of chronic generalized periodontitis of mild to moderate severity in 100 adults, with the appointment of probiotic in one group. The level of the oral hygiene and the state of periodontal tissues were estimated by the standard dental indieces. It was found that probiotics used in complex of preventive and treatment measures, regardless of the technology of their creation, contribute to positive clinical dynamics, namely to improve oral hygiene and the condition of the periodontal tissues.

Persistence of bifidobacteria in the intestines of calves after administration in freeze-dried form or in fermented milk

In order to improve the gut microbiome of calves, probiotic bacteria can be fed as active living-cells (fermented milk), or as live but inactive (freeze-dried) cultures. Ten bifidobacterial strains with suitable probiotic properties (as determined in our previous study) were tested for survival during the freeze-drying process, and screened for their ability to ferment cow's milk. The viability of both freeze-dried and live-cell cultures during storage was also tested. All of the strains tested were able to ferment cow's milk, with average counts of 8.26 ± 0.62 log CFU/ml. Eight out of the ten strains were able to survive in milk for 2 months in counts higher than 106 CFU/ml. Bifidobacteria showed high viability following the freeze-drying process, with average numbers of 9.03 ± 0.22 log CFU/vial and did not decrease after 12 months of storage. The mixture of rifampicin-resistant variants of bifidobacteria (RRBs) was fed to 2-day-old dairy Charolais calves in the form of living-cells, or as freeze-dried bacteria. The control group was given no probiotics. Survival of the RRBs administered and the numbers of other bacterial groups in faecal samples was monitored by culturing. Bifidobacteria that were administered passed successfully through the upper parts of the gastrointestinal tract, and were found in numbers higher than 109 CFU/g for two weeks. RRBs colonized the intestines of calves for at least 63 days in both treatment groups. Significantly higher total counts of bifidobacteria were found in the treated groups, compared to the control group. Reduction in Escherichia coli and total coliforms numbers, and an increase in lactobacilli counts were observed in both experimental groups following the application of the probiotic mixtures. Our results show that both forms of administering probiotic bifidobacteria to calves are effective, but that the freeze-dried form is more suitable from a practical viewpoint.

Impact of the freeze-drying process on product appearance, residual moisture content, viability, and batch uniformity of freeze-dried bacterial cultures safeguarded at culture collections

In this study, causes of collapsed bacterial cultures in glass ampoules observed after freeze-drying were investigated as well as the influence of collapse on residual moisture content (RMC) and viability. Also, the effect of heat radiation and post freeze-drying treatments on the RMC was studied. Cake morphologies of 21 bacterial strains obtained after freeze-drying with one standard protocol could be classified visually into four major types: no collapse, porous, partial collapse, and collapse. The more pronounced the collapse, the higher residual moisture content of the freeze-dried product, ranging from 1.53% for non-collapsed products to 3.62% for collapsed products. The most important cause of collapse was the mass of the inserted cotton plug in the ampoule. Default cotton plugs with a mass between 21 and 30mg inside the ampoule did not affect the viability of freeze-dried Aliivibrio fischeri LMG 4414(T) compared to ampoules without cotton plugs. Cotton plugs with a mass higher than 65mg inside the ampoule induced a full collapsed product with rubbery look (melt-back) and decreasing viability during storage. Heat radiation effects in the freeze-drying chamber and post freeze-drying treatments such as exposure time to air after freeze-drying and manifold drying time prior to heat sealing of ampoules influenced the RMC of freeze-dried products. To produce uniform batches of freeze-dried bacterial strains with intact cake structures and highest viabilities, inserted cotton plugs should not exceed 21mg per ampoule. Furthermore, heat radiation effects should be calculated in the design of the primary drying phase and manifold drying time before heat sealing should be determined as a function of exposure time to air.

Optimization Of Freeze-Dried Starter For Yogurt By Full Factorial Experimental Design

Abstract With the rapidly development of fermented milk product, it is significant for enhancing the performance of starter culture. This paper not only investigated the influence of anti-freeze factors and freeze-drying protective agents on viable count, freeze-drying survival rate and yield of Lactobacillus bulgaricus (LB) and Streptococcus thermophilus (ST), but also optimized the bacteria proportion of freeze-dried starter culture for yogurt by full factorial experimental design. The results showed as following: the freeze-drying protective agents or anti-freeze factors could enhanced survival rate of LB and ST; the freeze-dried LB and ST powders containing both of anti-freeze factors and freeze-drying protective agents had higher viable count and freeze-drying survival rate that were 84.7% and 79.7% respectively; In terms of fermentation performance, the best group of freeze-dried starter for yogurt was the compound of LB3 and ST2.

Production of freeze-dried yeast culture for the brewing of traditional sorghum beer, tchapalo.

Freeze-drying is a well-known dehydration method widely used to preserve microorganisms. In order to produce freeze-dried yeast starter culture for the brewing purpose of African sorghum beer, we tested protective agents (sucrose, glucose, glycerol) in combination with support materials (millet, maize, sorghum, and cassava flours) at 1:1 ratio (v/v). The yeast strains Saccharomyces cerevisiae F 12-7 and Candida tropicalis C 0-7 previously isolated from sorghum beer were used in a mixed culture at a ratio of 2:1 (C.tropicalis/S.cerevisiae). After the freeze-drying, the residual water contents were between 0.78 -2.27%, 0.55 -4.09%, and 0.40-2.61%, respectively, with sucrose, glucose and glycerol. The dried yeasts viabilities were between 4.0% and 10.6%. Among the protective agents used, sucrose was found to be the best protectant giving cell viabilities of 8.4-10.6%. Considering the support materials, millet flour was the best support after drying. When the freeze-dried yeast powders were stored at 4°C and room temperature (25-28°C) for up to 3months, the survival rates were the highest with cassava flour as the support material.

Xenorhabuds nematophila 세균 배양액 유래 미확인 생리활성 물질의 비티플러스 살충력 상승효과

`Bt-Plus` has been developed by mixing spores of Bacillus thuringiensis (Bt) and culture broth of Xenorhabdus nematophila (Xn). Despite its high toxicity, it has some imitation to broaden its efficacy against diverse insect pest spectrum. This study focuses on enhancement of Bt-Plus toxicity against semi-susceptible insect, Spodoptera exitgua, by addition of Xn metabolites. Two main Xn metabolites, oxindole (OI) and benzylideneacetone (BZA), are known to enhance the Bt insecticidal activities. The addition of OI or BZA significantly increased Bt-Plus pathogenicity. However, when the freeze-dried Xn culture broth was added to Bt-Plus, much less amount was enough to enhance the toxicity compared to the amount of OI or BZA. An HPLC analysis indicated that there were more than 12 unidentifed bacterial metabolites in Xn culture broth. These suggest that there are potent biological response modifiers in Xn metabolites other than OI and BZA.

Comparison of Antimicrobial Efficacy of Brazilian Propolis With Chlorhexidine and Sodium Fluoride Against Common Oral Pathogens: An In Vitro Study

Background: Oral diseases continue to represent a major health problem worldwide. Various bacteria and fungi are found to be the possible pathogens responsible for the oral disease. Objectives: The present in vitro study was conducted to compare the antimicrobial efficacy of mouthrinse (MR) prepared from Brazilian propolis with that of two commercially available MR, Hexidine (chlorhexidine mouthrinse) (CHX), S-Flo (0.2% sodium fluoride) against common oral pathogens i.e. Streptococcus mutans, Candida albicans and Escherichia coli. Materials and Methods: The antimicrobial efficacy of three MR was measured against freeze-dried culture of S. mutans (MTCC 890), E. coli (MTCC 44) and C. albicans (MTCC 1637).The antimicrobial activity was determined by the agar well diffusion method and the zone of inhibition produced by the mouthwashes against the test organisms was measured. The data were analyzed using SPSS software, version 20 and the one-way ANOVA test was used to compare in vitro antimicrobial activity of various MR. Results: The antimicrobial efficacy of Hexidine against S. mutans and E. coli was higher compared to that of C. albicans. The Brazilian Propolis (P) MR showed antimicrobial action against S. mutans and C. albicans. The antimicrobial efficacy of P against C. albicans was higher compared to that of CHX. The S-Flo MR (0.2% sodium fluoride) and the negative control group did not show any zone of inhibition against all three test stains. Conclusions: The results of the present study indicate that Brazilian Propolis demonstrated in vitro anti-microbial efficacy against S. mutans and C. albicans.

Optimizing Production of Two Potential Probiotic Lactobacilli Strains Isolated from Piglet Feces as Feed Additives for Weaned Piglets.

Two probiotic strains, Lactobacillus johnsonii x-1d-2 and Lactobacillus mucosae x-4w-1, originally isolated from piglet feces, have been demonstrated to possess antimicrobial activities, antibiotic resistances and interleukin-6 induction ability in RAW 267.4 macrophages in our previous study. These characteristics make L. johnsonii x-1d-2 and L. mucosae x-4w-1 good candidates for application in feed probiotics. In this study, soybeal meal, molasses and sodium acetate were selected to optimize the growth medium for cultivation of L. johnsonii x-1d-2 and L. mucosae x-4w-1. These two strains were then freeze-dried and mixed into the basal diet to feed the weaned piglets. The effects of L. johnsonii x-1d-2 and L. mucosae x-4w-1 on the growth performance and fecal microflora of weaned piglets were investigated. The results showed that the bacterial numbers of L. johnsonii x-1d-2 and L. mucosae x-4w-1 reached a maximum of 8.90 and 9.30 log CFU/mL, respectively, when growing in optimal medium consisting of 5.5% (wt/vol) soybean meal, 1.0% (wt/vol) molasses and 1.0% (wt/vol) sodium acetate. The medium cost was 96% lower than the commercial de Man, Rogosa and Sharpe medium. In a further feeding study, the weaned piglets fed basal diet supplemented with freeze-dried probiotic cultures exhibited higher (p<0.05) body weight gain, feed intake, and gain/feed ratio than weaned piglets fed basal diet. Probiotic feeding also increased the numbers of lactobacilli and decreased the numbers of E. coli in the feces of weaned piglets. This study demonstrates that L. johnsonii x-1d-2 and L. mucosae x-4w-1 have high potential to be used as feed additives in the pig industry.

Protective media composition influence on freezedried bacteria Lactobacillus plantarum ONU315 viability and biotechnological properties saving

Creation of freeze-dried cultures of lactobacteria for fermentation of fruiting bodies of edible fungi is a prospective innovation in microbiological industry and functional nutrition. Selection of a protective medium for freeze-drying contributes to increase of resistance of bacterial cells to injuries in the process of freeze-drying, stabilisation of their vital functions and preservation of high number of viable cells during long time after drying.The aim of the work was to study the impact of composition of protective media on preservation of viability and biotechnological properties of bacteria of strain Lactobacillus plantarum ONU315 after lyophilisation.The object of the research was strain of lactobacteria L. plantarum ONU315, obtained from fruiting bodies of oyster mushroom of strain Chinese black, artificially cultivated in Odesa region.Application of protective medium, composition of which includes skimmed milk (40%), sucrose (20%), sodium citrate (20%), lactose (9.5%), maltose (9.5%) and gelatine (1%) makes it possible to preserve viability and biochemical activity of lyophilised bacteria of strain L. plantarum ONU315. Lyophilised lactobacteria of strain L. plantarum ONU315 preserved antagonistic activity to representatives of microbiota of fruiting bodies of oyster mushroom for 6 months.

EFFICACY OF PROBIOTICS INTAKE ON INTERNAL MILIEU OF HENS

The aim of present study was to evaluate the functional efficiency of probiotic preparation on selected blood biochemical parameters of ISA Brown hens. Feed in the experimental group of hens was enriched with a probiotic preparation in the dose of 500g.t-1 consisted of freeze-dried cultures: Lactobacillus bulgaricus LAT 187, L. acidophilus LAT 180, L. helveticus LAT 179, L. delbrueckii ssp. Lactis LAT 182, Streptococcus thermophiles LAT 205, Enterococcus faecium E-253 with concentration of 5.109 (CFU LAB) living organisms in 1 gram. Blood samples were collected in 25 and 48 week of hens’ age. Biochemical parameters of mineral profile (calcium, phosphorus, magnesium, sodium, potassium, chlorides), energetic profile (plasma total cholesterol, triglycerides, total proteins, bilirubin, glucose), and activities of serum liver enzymes (aspartate aminotransferase AST, alanine aminotransferase ALT, alkaline phosphatase ALP) were analysed using Ecoline kits and a semi-automated clinical chemistry analyser Microlab 300 (Vilat Scientific, Dieren, The Nederland). Probiotic preparation reduced (P

Selection and Characterization of Biofuel-Producing Environmental Bacteria Isolated from Vegetable Oil-Rich Wastes

Fossil fuels are consumed so rapidly that it is expected that the planet resources will be soon exhausted. Therefore, it is imperative to develop alternative and inexpensive new technologies to produce sustainable fuels, for example biodiesel. In addition to hydrolytic and esterification reactions, lipases are capable of performing transesterification reactions useful for the production of biodiesel. However selection of the lipases capable of performing transesterification reactions is not easy and consequently very few biodiesel producing lipases are currently available. In this work we first isolated 1,016 lipolytic microorganisms by a qualitative plate assay. In a second step, lipolytic bacteria were analyzed using a colorimetric assay to detect the transesterification activity. Thirty of the initial lipolytic strains were selected for further characterization. Phylogenetic analysis revealed that 23 of the bacterial isolates were Gram negative and 7 were Gram positive, belonging to different clades. Biofuel production was analyzed and quantified by gas chromatography and revealed that 5 of the isolates produced biofuel with yields higher than 80% at benchtop scale. Chemical and viscosity analysis of the produced biofuel revealed that it differed from biodiesel. This bacterial-derived biofuel does not require any further downstream processing and it can be used directly in engines. The freeze-dried bacterial culture supernatants could be used at least five times for biofuel production without diminishing their activity. Therefore, these 5 isolates represent excellent candidates for testing biofuel production at industrial scale.

A combination of acid lactase from Aspergillus oryzae and yogurt bacteria improves lactose digestion in lactose maldigesters synergistically: A randomized, controlled, double-blind cross-over trial

Lactose digestion can be improved in subjects with impaired or completely absent intestinal lactase activity by administration of lactase preparations and particularly of acid lactase, which is active in the stomach, or by yogurt containing live lactic acid bacteria. It is the question, if lactose digestion can be further enhanced by combining these two approaches. We investigated in a randomised, placebo-controlled, double-blind, 5-arm crossover study on 24 lactose malabsorbers with variable degrees of lactase deficiency if different lactase preparations and freeze-dried yogurt culture affect gastrointestinal lactose digestion after consuming moderate amounts of lactose (12.5 g) by assessing hydrogen exhalation over 6 h. Furthermore, symptoms of lactose intolerance (excess gas production, abdominal pain, diarrhoea or nausea) were assessed using validated questionnaires. All preparations increased lactose digestion and reduced peak hydrogen exhalation by -27% (yogurt), -29/-33% (3300/9000 FCC(1) ((1) One FCC hydrolyses about 5 or 1.7-2.5 mg lactose in aquous solution or in (artificial) chyme, respectively, according to the FCC-III method of the Committee on Codex Specifications, Food and Nutrition Board, National Research Council. Food Chemicals Codex, 3rd edition. Washington, DC, National Academy Press, 1981 It cannot precisely be defined how much lactose can be hydrolysed in vivo by the consumption of a certain number of FCC units.) units acid lactase from Aspergillus oryzae) or -46%, respectively (3300 FCC units lactase plus yogurt culture combined), as compared with placebo (p < 0.001, Friedman test). The combination preparation had not only the strongest effect, but also showed the lowest variance in H(2)-exhalation values (less malabsorbers with no reduction of H(2)-exhalation) Apart from this, both the higher dose lactase and the combination preparation significantly reduced the symptoms most closely associated with H(2)-exhalation, namely flatulences and abdominal pain, respectively. The combined administration of freeze-dried yogurt cultures and acid lactase increases lactose digestion more than either freeze-dried yogurt cultures or acid lactase alone, and more lactose malabsorbers benefited from this effect.

Effect of the Incorporation of Different Freeze-Dried Cultures on the Properties of Sourdough Bread

The application of strains of Lactobacillus paracasei (LP1 and LP2) and Saccharomyces cerevisiae (SC1 and SC2) as starter cultures for sourdough bread making was analyzed. The physicochemical, microbiologial, specific volume, texture, color, microstructural, and sensorial properties of sourdough bread were evaluated. The highest specific volume obtained was for breads made with SC1. Breads made with LP2 or with a combination treatment (LP2/SC1 and LP2/SC2) had improved crumb softness relative to samples with LP1 or with a combination treatment (LP1/SC1 and LP1/SC2). The best scores for sensory analysis were found in breads containing LP2/SC1 in formulation.

English

In order to determine the optimum dosage of starter culture for yoghurt produced from zebu milk, fresh milk was inoculated with 5, 10, 15, 20, and 25g/L of freeze-dried starter culture. Proximate composition, gel formation, pH, sensory properties and acceptance of yoghurts inoculated with different dosage of starter culture were evaluated after 2, 4, 6, 8 and 10 h of incubation. Total solids, protein and carbohydrate content of yoghurts increased significantly (p 20>15>10>5 g/L. Increasing dosage of starter culture improved physicochemical properties of yoghurt and shortened time of gel formation.

Nutritional Benefits of Bifidobacterium Lactis in Dairy Products

Abstract Bifidobacteria are one of the most important probiotics in dairy products. They have positive effects on human health. Nutritional benefits of bifidobacteria are genetically determined and can be promoted with addition of prebiotics. The aim of the present study was to examine the properties of Bifidobacterium lactis in dairy products. Pasteurised milk, freeze-dried starter culture Bb-12 (Bifidobacterium lactis, Chr. Hansen, Denmark), syrup of lactulose (Duphalac®, the Netherlands), and inulin (“Raftiline®HP”, ORAFI, Belgium) were used in the experiments. The optimal concentrations of lactulose (2%) and inulin (4%) were established in preliminary studies, based on quality indices and nutritional value of fermented dairy products (Beitane, 2008). Amino acids, carbohydrates, such as lactose, lactulose and inulin, as well as cholesterol were determined during the study using appropriate analytical procedures. The enzymatic activity of bifidobacteria determines nutritional value of the fermented dairy products. Addition of 2% lactulose resulted in significant increase of some amino acid concentrations, such as leucine, phenylalanine, lysine and arginine concentrations (P &lt; 0.05), compared with those in other treatments. The presence of prebiotics caused a decrease of cholesterol level by 35% and lactose content by 31% in fermented milk samples. The enzymatic activity of bifidobacteria should be promoted with addition of lactulose and inulin to increase nutritional value of functional dairy products.

A cost-effective and simple alternative technique for reconstitution of freeze-dried cultures of Neisseria gonorrhoeae

A cost-effective and simple alternative technique for reconstitution of freeze-dried cultures of Neisseria gonorrhoeae

English

Ten commercially available probiotic products were collected from the local market of Lahore, Pakistan; including dairy, freeze dried products and fruit drinks. These products were examined by using culture dependent methods, SDS-PAGE as well as by visualization of denaturing gradient gel electrophoresis (DGGE) band profiles under UV light. Identical results of the DGGE and culture-dependent analysis of the 10 probiotic products were found. A DGGE analysis of five products (Nestle yogurt, Haleeb flavored yogurt, Haleeb yoghurt, Freeze-dried product and Nestle fruit yogurt) detectedBifidobacterium lactis, Streptococcus thermophilus, Lactobacillus delbrueckii subsp.bulgaricus, Bifidobacterium lactis, Lactobacillus casei, Lactobacillus acidophilus,Lactobacillus rhamnosus, Bacillus cereus and Streptococcus thermophilus that were the same as with conventional isolation procedures. For the remaining five products (Nestle nido, Haleeb Xtra energy milk, Haleeb Labban, Haleeb chadder cheese, and freeze-dried culture), DGGE analysis was able to detect more species (L. delbrueckii subsp.bulgaricus, L. rhamnosus, L. acidophilus, L. casei, and L. acidophilus) than were recovered by culture-dependent methods. The present study has proved that the PCR-DGGE and and phenotypic identification methods may result in a very powerful tool for both qualitative and quantitative analyses of all kinds of (bacterial) fermentation products. Key words: Probiotic products, polyerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) method, culture-dependent analysis.

A study on Bifidobacterium lactis Bb12 viability in bread during baking

Bread was made from dough with an addition of freeze-dried culture of the probiotic strain Bifidobacterium lactis Bb12 (Bb12). The viable cell counts, specific volume, moisture content and water activity of the bread were determined after baking for 0, 3, 6, 9, 12min at 165, 185, 205°C, respectively. The viable counts of Bb12 in both the core and the middle sections of the bread declined significantly during baking. However, some bacteria survived in the bread even after baking for 12min. Moreover, the specific volumes and moisture contents of the bread increased with baking, and water activity of bread remained almost the same during baking.