Bakery Yeast Research Articles

Bioethanol Production and Optimization test from Agricultural Waste: The case of wet coffee processing waste (pulp

The objective of this study was to evaluate the feasibility of ethanol production and optimization from coffee pulp by using commercial bakery yeast, i.e., S. cereviciae . To conduct this study, fermentation was held at temperature 30 °C and pH 5. Coffee pulp was hydrolyzed by refluxing, a solid to liquid ratio of 1:10, using dilute sulfuric acid (1, 2 and 4 %) and distilled water at hydrolysis time of 1, 2, 4, 6 and 10 hours keeping boiling temperature. 90 % maximum total sugar concentration was obtained at 4 hours acid free hydrolysis. Based on these hydrolysis results, fermentation process was performed. In the process, it was observed that ethanol concentration decreased with an increase in acid concentration, hydrolysis time and fermentation time. The maximum result was obtained with distilled water hydrolysis for 4 hours and 24 hours fermentation. Under these conditions maximum ethanol concentration production was 7.4 g/L. The result indicated that being available in plentiful amounts and non-edible material, coffee pulp will be potential feedstock for bioethanol production in Ethiopia.

Analysis of Genetic Determination of <I>Vibrio cholerae</I> Tweenase Activity

Studied are Vibrio cholerae of different serogroups on the presence of cef (CHO cell elongating factor) gene and activity against tweens and tributyrin using HDS-agar, prepared on the basis of bakery yeast pancreatic digest. Determined is the fact that all cef-positive strains hydrolyze tweens 20, 40, 60, 80, 85 and all but toxigenic V.cholerae O139, hydrolyze tributyrin. In contrast, non-toxigenic cef-negative strains of O139 serogroup, are active only against the latter. Apparently, the tweenase activity of Vibrio cholerae is provided, partly, by Cef, and the ability to hydrolyze tributyrin is the result of combined activity of Cef and other ferments. Shown is the efficiency of HDS-agar application to determine these characteristics.

Effect of particle size reduction, hydrothermal and fermentation treatments on phytic acid content and some physicochemical properties of wheat bran.

With the aim of reducing phytic acid content of wheat bran, particle size reduction (from 1,200 to 90μm), hydrothermal (wet steeping in acetate buffer at pH 4.8 at 55°C for 60min) and fermentation (using bakery yeast for 8h at 30°C) and combination of these treatments with particle size reduction were applied and their effects on some properties of the bran were studied. Phytic acid content decreased from 50.1 to 21.6, 32.8 and 43.9mg/g after particle size reduction, hydrothermal and fermentation, respectively. Particle size reduction along with these treatments further reduced phytic acid content up to 76.4% and 57.3%, respectively. Hydrothermal and fermentation decreased, while particle size reduction alone or in combination increased bran lightness. With reducing particle size, total, soluble and insoluble fiber content decreased from 69.7 to 32.1%, 12.2 to 7.9% and 57.4 to 24.3%, respectively. The highest total (74.4%) and soluble (21.4%) and the lowest insoluble fiber (52.1%) content were determined for the hydrothermaled bran. Particle size reduction decreased swelling power, water solubility and water holding capacity. Swelling power and water holding capacity of the hydrothermaled and fermented brans were lower, while water solubility was higher than the control. The amount of Fe(+2), Zn(+2) and Ca(+2) decreased with reducing particle size. Fermentation had no effect on Fe(+2)and Zn(+2) but slightly reduced Ca(+2). The hydrothermal treatment slightly decreased these elements. Amongst all, hydrothermal treatment along with particle size reduction resulted in the lowest phytic acid and highest fiber content.

Electrostatic Droplet Generator with 3-Coaxial-Nozzle Head for Microencapsulation of Living Cells in Hydrogel Covered by Synthetic Polymer Membranes

The current methods allow for encapsulation of cells inside spherical microcapsules made of a matrix covered by a permselective membrane using an electrostatic droplet generator with 1-nozzle or 2-nozzle heads. However, some potentially useful materials for the outer membranes cannot be put into direct contact with hydrophilic core filled by cells during the manufacturing process. Therefore, we designed a novel 3-coaxial-nozzle head that allows for the third fluid to separate the core material from the membrane material. The equipment was applied for manufacturing spherical microcapsules comprised of cell-friendly alginate core surrounded by semipermeable polyethersulfone membrane. The obtained microcapsules had a diameter between 0.84 mm and 1.79 mm, and the diameter correlated negatively with the applied electric voltage. The thickness of the membrane varied from 171 µm to 450 µm. The SEM images of the interior of microcapsules revealed highly porous membrane structure typical for synthetic membranes obtained by a wet phase inversion method. Bakery yeast cells encapsulated inside the alginate-polyethersulfone microcapsules retained their proliferation ability proving the effectiveness and safety of this encapsulation technique.

Saccharomyces Cerevisiae Used As Probiotic: Strains Characterization And Cell Viability

The assay aimed to evaluate the cell viability of commercial yeast strains for bakery purpose in comparison to a selected strain (Yea-Sacc® 1026 , Alltech®) indicated as a probiotic to be added to animal feed, promising yield gains. The objective of this first study was to check the number of viable cells, once the indicated product to be classified as probiotic needs to provide live cells. We tested the viability of one commercial probiotic strain (Yea-Sacc® 1026 ) in comparison to four bakery commercial yeast. Our results showed a low viability of the probiotic Saccharomyces cerevisiae , which was 7.7 % and the bakery yeasts around 35 % of viable cells. The sustainability calls for alternative sources for animal feeding and the use of microorganisms is very welcome in the livestock chain, provided that the product presented has the characteristics inherent to it.

Screening of medium components by Plackett–Burman design for carotenoid production using date (Phoenix dactylifera) wastes

This work was conducted to use palm date wastes in the production of carotenoids. Three strains of Lactobacillus plantarum (QS1, QS2 and QS3) were isolated from food samples including bakery's yeast, olive fermentation and cheese. Strains were investigated for their structural recA gene by PCR. The recA gene was successfully amplified from all strains under study. The ability of isolated L. plantarum strains to produce carotenoids in MRS broth was investigated. QS3 isolate gave the highest ability for production of carotenoids. Statistical screening of media components for production of carotenoids by L. plantarum QS3 using date syrup as a source of sugar was carried out using Plackett–Burman design. Date syrup at 5% sugar concentration produced 16.21mg/kg dry cell of carotenoids when used alone. Increase in carotenoids production was recovered (54.89mg/kg dry cell) with supplementation of MRS medium with salts and organic nitrogen after optimization of pH and temperature using date syrup as a carbon source. Plackett–Burman design showed peptone, K2HPO4, sodium acetate and date juice as main components affecting carotenoids production.

Interactive effects of dietary protein and live bakery yeast, Saccharomyces cerevisiae on growth performance of Nile tilapia, Oreochromis niloticus (L.) fry and their challenge against Aeromonas hydrophila infection

Yeasts used as a probiotic in fish diets could stimulate fish resistance against bacterial infection and could enhance the activities of digestive enzymes in fish guts. In addition to yeast importance, dietary protein is another important part in fish diets that should be carefully optimized to meet fish requirement. It is proposed that the yeast supplementation may enhance the dietary protein turnover and reduce the protein requirement for fish. Therefore, the interactive effects of dietary protein and yeast levels on the growth performance of Nile tilapia, Oreochromis niloticus (L.) fry and their challenge against Aeromonas hydrophila infection was evaluated. In the present study, ten experimental diets were formulated to contain either 35% or 45% crude protein (CP). For each protein level treatment, bakery yeast (Saccharomyces cerevisiae) was supplemented at 0.0, 0.50, 1.0, 2.0, or 5.0 g/kg diet. Fish (0.25–0.48 g) were distributed at a rate of 25 fish per 140-L aquarium. For each diet, triplicate aquaria were fed twice a day, 5 days a week for 12 weeks. Fish growth and feed utilization were significantly affected by either dietary protein or yeast levels alone, while no significant effect of their interaction was observed. The highest fish growth was obtained at 1.0–5.0 g yeast/kg diet at both protein levels; however, the fish performance at 45% CP was better than that fed on 35% CP diets. The optimum feed conversion ratio (FCR) was obtained when fish fed on 1.0–5.0 and 2.0–5.0 g yeast/kg diet at 35 and 45% CP, respectively. The cumulative fish mortality, after interperitoneal injection with A. hydrophila for 10 days, and bactericidal activity was significantly higher in fish fed 35% CP diets than those fed 45% CP diets. Both variables decreased significantly with the increase in yeast levels. The lowest bacterial count and bactericidal activity were obtained in fish fed 5.0 g yeast/kg diet irrespective to dietary protein levels. It could be concluded that the inclusion of live bakery yeast in practical diets could improve the growth performances, feed utilization, and physiological status of Nile tilapia fry and their challenge against A. hydrophila infection. Moreover, fish performance when fed 45% CP diet was better than those fed 35% CP diet. Based on these results, the most suitable yeast level for maximum Nile tilapia growth was determined to be 2.0 g yeast/kg diet with 45% CP diet; however, this level was recommended to stimulate their productive performance and enhances their resistance against A. hydrophila infection.

Comparison of biochemical changes during alcoholic fermentation of cocoa juice conducted by spontaneous and induced processes for the production of ethanol

Ivory Coast (Côte d´Ivoire) is the biggest cocoa producing country in the world with an average 1405 000 metric tons of cocoa beans. It also produces several quantities of cocoa mucilage juice during cocoa harvesting. In spite of its high sugar and over minerals content, cocoa juice is currently abandoned in farms. This study aims to compare the nature of products resulted from a spontaneous fermentation conducted by uncontrolled or indigenous yeasts to those from a controlled fermentation made by using commercial bakery yeast such as Saccharomyces cereviciae at a rate of 30g/hL during 3 to 5 days of cocoa mucilaginous juice. To conduct this study, fermentations were held at different temperatures 28, 30, 35 and 41°C. Chemical analyses related to the pH by pH-meter, total sugar content using standard method and to the measurement of the yield of ethanol using a gas chromatography (CPG), microbial count were carried out. Analyses showed that yeast, mould, aerobic mesophilic and lactic acid bacteria were isolated in almost all samples. Cocoa shield was shown to contain the highest number of yeast and mould at 1.6x104 CFUcm-2, aerobic mesophilic flora at 1.5x105 CFUcm-2 and lactic acid bacteria at 2.1x104 CFUcm-2. Whatever the type of fermentation, yields of ethanol was highest at 30°C. Fermentation conducted with controlled yeast gave a better yield of ethanol with 8.4 % than spontaneous fermentation that yielded only 4.3 %. There were significant differences (p

EVALUATION OF BALADY BREAD MADE WITH SOUR DOUGH COMPARED TO THAT MADE BY BAKERY YEAST

This study was designed to evaluA batady bread made with sour dough, produced by using (water or milk) chemically, physically and organoleptically in comparison with the balady bread made by bakery yeast. Results of sensory evaluation suggested the superiority of balady bread made with (20%) sour dough produced by using water or milk and fermented for one day. The results indicated that using sour dough in bread-making increased the total titerable acidity which in turn reduced bacterial counts. On the other hand, bread made with (20%) sour dough produced by using milk had the longest shelf life at 250C. Also using sour dough delayed staling of the produced bread. The results indicated that bread made with sour dough is a rather good source of vitamins. The results may recommend the use of sour dough (20%), fermented for 2days in balady bread making.

Estimation levels of Indol acetic acid (IAA) and Gibberellic acid (GA3) from dry bakery yeast Saccharomyces cereviciae

The level of endogenous free, bound and total auxin (Indol-3-acitic acid, IAA) and gibberellic acid (GA3) were examined in dry bakery yeast. For determination of the levels of these plant growth regulators level, used spectrophotometer. The results show that Saccharomyces cereviciae was produced IAA and GA3. IAA level was 29.86 µg/ml, 198 µg/ml at 222nm and 280nm wavelengths respectively and GA3 level was 799 µg/ml at 254nm.

Determination of Thiols in Yeast by HPLC Coupled with LTQ-Orbitrap Mass Spectrometry after Derivatization with p-(Hydroxymercuri)benzoate

A liquid chromatography method with mass spectrometric detection has been developed for the simultaneous determination of six thiols in the sulfur metabolic pathway, including cysteine (Cys), homocysteine (HCys), glutathione (GSH), cysteinyl-glycine (Cys-Gly), gamma-glutamyl-cysteine (Glu-Cys), and S-adenosyl-homocysteine (AdoHcy). Tris(2-carboxyethyl)phosphine (TCEP) was used as the reducing reagent and p-(hydroxymercuri)benzoate (PHMB) as the derivatization reagent. Thiols were extracted from 3 mg of yeast using water in an ultrasonic bath. The absolute detection limits for the compounds studied were in the subpicomole range. It was found that AdoHcy, Cys, GSH, Cys-Gly, Glu-Cys, and very little HCys were present in the selenium-enriched yeast sample studied, and GSH, Glu-Cys, very little AdoHcy, Cys, and Cys-Gly were present in three bakery yeasts.

EFFECT OF FEED WITHDRAWAL AND ADDING DRIED BAKERY YEAST IN THE DIET ON DRESSING PERCENTAGES AND MEAT CHEMICAL COMPOSITION OF BROILERS

This study has been conducted to study the effect of feed withdrawal (8 hours after slaughter) andadding dried bakery yeast on dressing percentage and meat chemical 45 marketed broiler chickens at 8weeks of age .The birds randomly distributed into three treatments (5 birds ) and each treatment tothree replicates (5 birds per replicate ) which were: un-treated control (T1) , broiler chickens subjectedto feed withdrawal 8 hrs. before slautered (T2) , broiler chickens fed a diet contained 1% of driedbakery yeast three days before subjected to feed withdrawal 8 hrs. before slaughtered (T3) . The dataobtained revealed the following :-Adding dried bakery yeast three days before subjected to feed withdrawal 8 hrs. beforeslaughtered (T3) significantly (p<0.01) decreased live body weight in the same time increased (p<0.01)carcass weight , dressing percentage with or without gibletts and gibletts percentage , also T3significantly (p<0.01) increased protein and decreased lipid and cholesterol of breast and legs meatcompaired with Feed withdrawal (T2) which significantly (p<0.01) predominent compaired with T1 .

Controle de doenças foliares e de flores e qualidade pós-colheita do morangueiro tratado com Saccharomyces cerevisiae

O efeito de diferentes preparações de Saccharomyces cerevisiae foi avaliado sobre o desenvolvimento das doenças do morangueiro, como mancha-de-micosferela (Mycosphaerella fragariae), mancha-de-dendrofoma (Dendrophoma obscurans) e flor-preta (Colletotrichum acutatum) além da qualidade pós-colheita dos frutos. O trabalho foi realizado entre 2004 e 2005 na Universidade Tecnológica Federal do Paraná, Campus Dois Vizinhos. Os tratamentos consistiram de pulverizações semanais de cinco diferentes preparados a partir da levedura S. cerevisiae: suspensão com fermento biológico fresco comercial, suspensão de células de levedura, suspensão autoclavada de células, filtrado de cultura em meio líquido e Agro-MOS®, produto comercial formulado a partir da levedura, além da testemunha com água destilada e do tratamento controle com fungicidas. Nenhuma das preparações apresentou efeito contra a mancha-de-micosferela; preparações com a presença de células vivas e o produto Agro-MOS® apresentaram efeito contra mancha-de-dendrofoma; preparações com suspensão do produto comercial e filtrado de cultura líquida reduziram a incidência de flor-preta em flores e frutos. Preparações de S. cerevisiae com suspensão de células, suspensão autoclavada de células e filtrado de cultura líquida promoveram aumento na produtividade dos morangueiros que variou de 589,6 a 617,8 g planta-1. Preparações de S. cerevisiae, com presença de células vivas ou não, alteraram o metabolismo do morangueiro, aumentando a atividade das enzimas quitinase e glucanase, envolvidas na resistência sistêmica adquirida. Todos os tratamentos, com exceção do tratamento com suspensão autoclavada de células, reduziram a incidência de mofo-cinzento em pós-colheita de frutos.

Aceitação e perfil sensorial das cachaças produzidas com Kefir e Saccharomyces cerevisae

Saccharomyces cerevisae is the main industrially used yeast to produce sugar cane spirits (cachaca). However, other microorganisms are able to produce ethanol using sugar as substrate. This work aimed at determining the sensory profile of cachaca produced through the alcoholic fermentation with Kefir's granules and its acceptance. The acceptance analysis was performed by 57 consumers using a 9 point structured hedonic scale to evaluate the aroma and the general acceptance of the product. The QDA method, with 8 trained tasters, was used to evaluate the following product descriptors: alcoholic aroma, alcoholic flavor, and burning and bitter taste. The evaluated samples did not presented statistical differences (p < 0.05) among each other regarding the aroma acceptance. However, the cachaca produced using bakery yeast presented higher acceptance scores. On the other hand, the analysis of general acceptance presented significant differences (p < 0.05) between the samples for alcoholic aroma and bitter taste. Cachaca produced with Kefir granules presented higher intensity of both of these attributes.

The acid hydrolysis of potato tuber mash in bioethanol production

The hydrolysis of starch from fresh potato tubers by HCl and H2SO4 at different ratios of plant material to acid solution was investigated. The final reducing sugars concentration in the hydrolyzates depended on the type and concentration of acid and the ratio of plant material to acid solution but not on the type of potato. The highest dextrose equivalent of 94%, the greatest reaction rate constant of 0.089 min −1 and the 5-hydroxymethylfurfural (5-HMF) yield of 0.04 g/L were achieved using 1 M HCl at the ratio of plant material to acid solution of 1:2 (w/v). The ethanol yield of 31 g/L was obtained in the fermentation of hydrolyzate prepared under the optimal hydrolysis conditions by commercial bakery yeast at 28 ◦ Cf or about 18 h.

Low folate content in gluten-free cereal products and their main ingredients

Folate content in some gluten-free cereal products and their main ingredients was determined using a validated method based on reversed-phase high performance liquid chromatography (HPLC) with fluorescence and diode array detection. The main folate forms found in gluten-free products were 5-methyl-tetrahydrofolate and tetrahydrofolate. Starches and low protein flours commonly used as main components in gluten-free products appeared to be poor folate sources with folate content ⩽6 μg/100 g fresh weight. Folate content in gluten-free breads was higher (15.1–35.9 μg folate/100 g fresh weight) due to use of bakery yeast which is a rich folate source. Overall, folate content in gluten-free products was lower than in their gluten-containing counterparts. Therefore, fortification of gluten-free products with folic acid or enrichment of these products with nutrient-dense fractions of cereals naturally free from gluten (such as buckwheat, quinoa, amaranth or millet) can be of interest.

Influence of culture medium composition, dissolved oxygen concentration and harvesting time on the production of Serratia entomophila, a microbial control agent of the New Zealand grass grub

The bacterium Serratia entomophila (Enterobacteriaceae) has been developed as a commercially available biopesticide for control of the pasture pest Costelytra zealandica. The influence of culture medium composition, dissolved oxygen (DO) concentration and harvesting time were investigated in order to optimise the production of S. entomophila. In batch fermentations, highest yields were achieved using sucrose (40 g L−1) as the carbon source, followed closely by fructose and molasses. The effect of yeast extract (YE), marmite and bakery yeast as cell growth enhancers was also examined in both batch and fed-batch mode. Culture medium containing 20 g L−1 of YE (fed-batch) produced the highest cell density. No significant effect on cell yield was detected when cultures were supplemented with bakery yeast or marmite. The DO concentration influenced biomass production: a 5-fold increase in cell density was achieved when the concentration of DO was maintained in the range of 20–50% (5.7×1010 CFUs mL−1) in comparison with 1% (1.2×1010 CFUs mL−1). In cultures maintained at 1 and 20% DO concentration, cells harvested from the exponential growth phase survived for less than 2 weeks when stored at 4°C. In contrast, high cell survival (85–100%) was achieved when cells were harvested after they had entered the stationary growth phase. Recommendations are provided for the production of robust, high cell density cultures of S. entomophila.

Study The Effect Of Feed Withdrawal And Adding Dried Bakery Yeast In The Diet On ph And Some Microbial Types Of Broiler Chickens Intestine

This study has been conducted to study the effect of feed withdrawal and adding dried bakery yeast on pH and some microbial indicators which includes Total Bacterial Count (TBC) ,Coliform Count (CC) , Fungi Count (FC) and Lactobacilli Count (LC) in the gastro -intestinal tract of 45 marketed broiler chickens at 8 weeks of age .The birds randomly distributed into three treatments and each treatment to three replicates (15 birds per replicate ) which were: un -treated control (T1) , broiler chickens subjected to feed withdrawal 8 hrs. before slautered (T2) , broiler chickens fed a diet contained 1% of dried bakery yeast three days before subjected to feed withdrawal 8 hrs. before slautered (T3 ) . The data obtained revealed the&#x0D; following :-No statically differences in the pH of gastro -intestinal tract were appeared due to feed withdrawal and adding dried bakery yeast . Feed withdrawal (T2) caused a significant (p&lt;0.05) increase in TBC ,TC and FC in the intestine content compaired with T1 and T3 . Adding 1% of dried bakery yeast three days before subjected to feed withdrawal 8 hrs. before slautered (T3) caused a significant (p&lt;0.05) decreased in TBC,CC and FC , in the&#x0D; mean time LC significantly (p&lt;0.05) increased .

Intraspecies Diversity of the Industrial Yeast StrainsSaccharomyces cerevisiaeandSaccharomyces pastorianusBased on Analysis of the Sequences of the Internal Transcribed Spacer (ITS) Regions and the D1/D2 Region of 26S rDNA

We divided industrial yeast strains of Saccharomyces cerevisiae into three groups based on the sequences of their internal transcribed spacer (ITS) regions. One group contained sake yeasts, shochu yeasts, and one bakery yeast, another group contained wine yeasts, and the third group contained beer and whisky yeasts, including seven bakery yeasts. The three groups were distinguished by polymorphisms at two positions, designated positions B and C, corresponding to nucleotide numbers 279 and 301 respectively in the S288C strain. The yeasts in the Japanese group had one thymine at position B and one thymine at position C. The wine yeasts had one thymine at position B and one cytosine at position C. And the beer and whisky yeasts had two thymines at position B and one cytosine at position C. Strains of S. pastorianus were divided into three groups based on the sequences of their 26S rDNA D1/D2 and ITS regions.

Ukrainian dietary bakery product with selenium-enriched yeast

Bread is a most important food product and source of selenium in Ukraine. However, low content of selenium in wheat flour from north and northwest regions of Ukraine does not ensure the recommended consumption of selenium. Daily intake of selenium by the population of North Ukraine is below recommended allowance. The aim of this research was to study the production of the dietary rolls with selenium-enriched yeast for the population of North Ukraine. The study showed that to obtain bakery yeast of good quality, concentration of sodium hydroselenite in the medium for yeast cultivation should be in the range from 2 to 5 μg Se/ml. Under these concentrations of selenium in medium, specific growth rate and biomass yield as well as bakery properties of the yeast Saccharomyces cerevisiae did not differ from the parameters of yeast, grown in the medium without selenium. Maturation of the selenium-enriched yeast improved their bakery properties. The 100 g wheat roll prepared with selenium-enriched yeast contained 50 μg Se (25% of the recommended daily allowance) in the form of selenomethionine, which is the best form of selenium for human consumption. These rolls can be used as a dietary product to reach recommended daily consumption of selenium by the population of North Ukraine and Chernobyl region.