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Search Results: 1 - 10 of 22474 matches for " post-fermentation time "
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黄酒酿造后酵工艺对氨基酸态氮生成的影响
潘慧青,曹钰,石慧媛,陆健,谢广发
- , 2016, DOI: 10.3969/j.issn.1673-1689.2016.02.005
Abstract: 黄酒的氨基酸态氮是用来反映其中的氨基酸及小肽总体水平的重要指标,其含量的高低直接影响黄酒的质量等级和整体风味。作者针对黄酒后酵阶段工艺条件进行研究,通过对发酵过程中蛋白质、氨基酸态氮、活酵母数的动态变化以及酒体的理化指标和氨基酸组成分析,考察后酵时间和温度对氨基酸态氮生成的影响。结果表明,氨基酸态氮主要产生在黄酒后酵阶段,后发酵时间从14 d延长至17、20、23 d,氨基酸态氮的含量分别提高24.7%、31.7%和37.6%,酵母自溶过程对后酵末期氨基酸态氮的贡献显著。升高后酵温度有利于氨基酸态氮的形成,后酵温度对氨基酸态氮的形成同时受到蛋白质降解酶活性和酵母自溶两方面的综合影响。研究结果显示,氨基酸是氨基酸态氮的主要组成,其含氮量占氨基酸态氮60%以上。
Amino acid nitrogen (AAN) is an important indicator representing the overall level of amino acids and low molecular weight peptides in the Chinese rice wine,which content can affect the quality and flavor of wine. The influence of post-fermentation process parameters to AAN generating were discussed in this work,which included the post-fermentation time and post-fermentation temperature by tracing the dynamic changes of protein content,AAN content and amounts of viable yeast cells, Tricine analysis by SDS-PAGE,and the physicochemical indexes and amino acid composition of fermentation broth. The results showed that the post-fermentation was the main period for AAN producing. The content of AAN in draft rice wine was increased 24.7%,31.7% and 37.6%,respectively when post-fermentation time prolonged from 14 days to 17 days, 20 days and 23 days. Yeast autolysis process offered a significant contribution to AAN at end of post-fermentation. Meanwhile it had positive effect on AAN formation when post-fermentation temperature raised at range of 13 ℃ to 17 ℃. The results implied that AAN was influenced by both activities of protein degradation enzymes and the degree of yeast autolysis when post-fermentation temperature was changed. Furthermore,the work indicated that amino acids are the main composition of nitrogen compounds,which nitrogen content accounted for more than 60% of AAN. This study is aimed to understand the effect of process conditions on the AAN generating,which will benefit the quality improvement of Chinese rice wine
Effect of Lactic Acid Bacteria and Yeast Starter Cultures on the Soaking Time and Quality of “Ofada” Rice  [PDF]
Oluwafunmilayo Adeniran, Olusegun Atanda, Mojisola Edema, Olusola Oyewol
Food and Nutrition Sciences (FNS) , 2012, DOI: 10.4236/fns.2012.32030
Abstract: Freshly harvested paddy rice was randomly obtained from three different farms in “Ofada” town, Ogun State, Nigeria and processed according to the traditional parboiling method. The rice was inoculated singly with cultures of Lactobacillus amylophilus, Leuconostoc mesenteroides, Saccharomyces uvarum and Saccharomyces cerevisiae which were isolated from the soak-water. In order to assess the effect of starter cultures on the soaking time of the rice, the pH and titratable acidity were determined at 12 h interval. The chemical composition and the sensory quality of the rice were also determined at the end of the soaking period while uninoculated rice served as control. The chemical composition of the rice as well as the pH and TTA of the soak-water were significantly (p < 0.05) different from the control while the processing time was shortened to 48 h. The rice inoculated with Saccharomyces uvarum and Saccharomyces cerevisae had the highest protein content and best sensory attributes.
Time Course Study for Yeast Invertase Production by Submerged Fermentation
Kiran Shafiq,Sikander Ali,Ikram-ul-Haq
Journal of Biological Sciences , 2003,
Abstract: The present investigation deals with the time course study of three different of Saccharomyces cerevisiae (GCB-K5, GCA-II and KR18) during invertase production by submerged fermentation. GCA-II was found to be the best producer of invertase (8.35 U ml ̄1, 48 h after inoculation) having high production yield coefficients (i.e., Yp/s and Yp/x). The product is a high cost product. Thus the use of optimized strain for invertase production is economically more feasible due to shorter incubation period and optimal production.
Post Fermentation Quality Changes in Bobozi Produced from Cassava (Manihot Esculenta Crantz) and the Effects of Sodium Metabisulphite Soaking in Combination with Refrigeration
I.S. Ogiehor,G.I. Okwu,E. Enaigbe
Pakistan Journal of Nutrition , 2004,
Abstract: Changes in the microbiological, physico-chemical and organoleptic quality of bobozi (African snack) produced from cassava (Manihot esculenta Crantz) during processing and the effects of sodium metabisulphite or in combination with refrigeration at 10oC were investigated results shows that the bioload increased from 0.3 x 101cfu/g to 1.04 x 105 at the 96th hours of fermentation and thereafter decreased gradually. Post fermentation soaking in 5% sodium metabisulphite decongest and reduced the bioload to 0.9 x 101 cfu/g. Extended storage of 48hrs fermented samples indicates slightly high count which peaked at 1.11 x 104 at 21st day of storage for samples stored at ambient temperature (30 2oC) whereas the bioload of refrigerated (10oC) samples were stable all through the 28 days of storage. Six bacteria genera (Bacillus, Streptococcus, Staphylococcus, Leuconostoc, Lactobacillus, and Corynebacterium, E Coli, Klebsiella and Salmonella) and few fungi genera (Candida, Geotrichum, Aspergillus and Penicillum dominated the preboiling and fermentation phase while (3) three bacteria genera (Bacillus, Streptococcus and Lactobacillus) and three (3) fungi group (Geotrichum, Aspergillus, and Penicillum) dominated the post fermentation and extended storage phase. However, E coli, Klebsialla and Salmonella) were eliminated after boiling and were not detected after 24hour of fermentation. The PH decreased from 4.58 0.01 to 3.75 0.02 at the end of the fermentation period. Although slight increase as to 4.31 0.02 was recorded after soaking in Sodium metabisulphite. Further decreased to 3.61 0.01 was recorded in samples held at 30 2oC whereas it was fairly stable in refrigerated samples all through the storage period. However, reverse pattern of changes was observed and recorded in the titratable acidity. Steady increase from 31.20 0.5 to 46.6 0.4 was recorded for the moisture content at the end of the fermentation period. Slight increase was recorded in the post fermented sample held at 30 2oC. Nevertheless, sample stored at 10oC were fairly stable. The hydrocyanic acid decreased through out the processing and storage period. Overall sensory acceptability scores shows that refrigerated samples were highly acceptable even though freshly prepared samples were preferred.
Prácticas poscosecha y de almacenamiento del cacao (Theobroma cacao) en el estado miranda Venezuela
Liendo,R.J.; Marín R.,C;
Revista de la Facultad de Agronomía , 2006,
Abstract: a survey with 150 farmers (that belong to all production sectors) of miranda, venezuela, located in three municipalities of barlovento was carried out, during the main crops from 1998 to 2000, in order to evaluate variations in post-harvest practices (post-harvest storage of the ears, the place where they ferment, fermentation method, stirring frequency and dryness), time of the exploitations, production levels of dry cacao, related activities to the post-harvest practices and storage conditions. statistical differences were observed with the ji-squared analysis (c2), among the different municipalities at two significant levels (p<0.05 and p<0.01), these differences show the variability in the post-harvest practices (excepting the stirring frequency), antiquity of the production unit, storage conditions and production levels of dry cacao. the factorial analysis of multiple correspondence revealed that the six classify variables: age of the exploitation unit, fermentation method, and characteristics of the place where they ferment, time of the dryness during the rainy periods, conditions of the place where they store the cacao and the production of dry cacao explained more than 45% of total variability. the ascendant hierarchical classification analysis allowed grouping the producers in ten types with defined profiles.
IDENTIFICACIóN DE LAS CAUSAS QUE ALTERAN EL RENDIMIENTO DE LOS EQUIPOS DE EXTRACCIóN DE MADERA: ESTUDIO DE TIEMPOS Y MOVIMIENTOS
ALVIS GORDO,JOSé FRANCO; SOTELO MU?OZ,MANUEL ALBERTO;
Biotecnología en el Sector Agropecuario y Agroindustrial , 2009,
Abstract: the time and motion studies to identify the causes that decrease the performance of logging equipment during the harvest, diagrams routine movements to determine the cycles (production unit) to get the optimum performance each group studied. statistical analysis was performed using a multiple linear regression can predict the behavior of variables and formulate a mathematical model that predicts the performance of each team, depending on different variables such as slope, distance woodlot and cargo carried. we designed a mathematical model that predicts yields woodlot operations to an average distance of 250 meters, slopes between 30 and 45% in plantations of pinus tecunumanii, oocarpa pinus, pinus patula and eucalyptus grandis.
Estudo comparativo entre duas técnicas de tonsilectomia: bisturi harm?nico (Ultracision) e dissec??o tradicional com bisturi de lamina fria
Ramos, Fernando A.;Ferreira, Roberto D. P.;Silva, Rubens H. da;Prado, Eloísa P. do;Corso, Renato J.;Pinto, José Antonio;
Revista Brasileira de Otorrinolaringologia , 2004, DOI: 10.1590/S0034-72992004000300006
Abstract: tonsillectomy is the most commom surgical procedure in otolaringology. the modifications and the technique surgical evolutions aim to simplifly and reduce the complications. the ultacisionò harmonic scalpel begin to be used in 1999 in tonsillectomies with good outcomes. aim: to compair the time of the procedure, bleeding and the need of trans operative hemostasis, post operative pain, healing aspect of the tonsilar fossa and complications in patients submitted to tonsillectomy with cold and ultrassonic scalpel. study design: transversal cohort. material and method: twenty six patients underwent tonsillectomy: 13 using the traditional thecnique with cold instruments and 13 using the ultrassonic one. they were evaluated with a standart protocol. the post operative pain were graduated through the horizontal visual scale analogue. results: surgical time were shorter with the ultrassonic thecnique compared to the traditional cold instruments. the amount of stitch at tonsilar fossa was lesser than the traditional thecnique. there were no post operative statistical difference in pain and in the aspect of the tonsilar fossa. conclusion: the ultrassonic scalpel is an excellent choice in surgeries where surgical time and transoperatory bleeding are important.
Investigation of the Post Time Dependence of PAGAT Gel Dosimeter by Electron Beams using MRI Technique
B. Azadbakht,K. Adinehvand
Research Journal of Applied Sciences, Engineering and Technology , 2012,
Abstract: In this study investigation of the post time dependence of PAGAT gel dosimeter by electron beams using MRI technique has been undertaken.Using MRI, the formulation to give the maximum change in the transverse relaxation rate R2(1/T2) was determined to be 4.5% N,N'-methylen-bis-acrylamide(bis), 4.5% acrylamid(AA), 5% gelatine, 5 mM tetrakis (hydroxymethyl) phosphonium chloride (THPC), 0.01 mM hydroquinone (HQ) and 86% HPLC (Water).When the preparation of final polymer gel solution is completed, it is transferred into phantoms and allowed to set by storage in a refrigerator at about 4oC. The optimal postmanufacture irradiation and post imaging times were both determined to be 1 day. The R2-dose response was linear up to 30 Gy. the response of the PAGAT gel is very similar in the lower dose region and The R2-dose response for doses less than 3 Gy is not exact. The R2-dose response of the PAGAT polymer gel dosimeter is linear between 10 to 30 Gy with R2-dose sensitivities of 0.0525, 0.0471, 0.0497 and 0.0541 S–1 Gy–1 when imaged at 1, 8, 15 and 29 days post-irradiation respectively. This study has shown that the normoxic PAGAT polymer gel has a properties of a dosimetric tool, which can be used in clinical radiotherapy.
Continuous gluconic acid production by Aureobasidium pullulans with and without biomass retention
Anastassiadis,Savas; Rehm,Hans-Jürgen;
Electronic Journal of Biotechnology , 2006,
Abstract: new alternative processes for the continuous production of gluconic acid by aureobasidium pullulans, using biomass retention by cell immobilization or cross over filtration, are described in the present work. 315 g/l gluconic acid was continuously produced in chemostat cultures at 21 hrs residence time without any biomass retention. 260 g/l gluconic acid was produced in fluidized bed reactor at 21 hrs residence time. the support carrier was overgrown resulting in limitations of oxygen transfer towards the inner layers of immobilized biomass. 375 g/l gluconic acid was produced under continuous cultivation at 22 hrs of residence time with a formation rate for the generic product of 17 g/(l x h) and a specific gluconic acid productivity of only 0.74 g/(g x h), using biomass retention by cross over filtration. 370 g/l were obtained at 19 hrs rt and 100% conversion with 25 g/l biomass and a formation rate of 19 g/(l x h). at 100% conversion, a selectivity of only 78% was determined at 22 hrs and of 77% at 19 hrs rt, because of the very high biomass concentration. biomass retention makes it possible to break the existing link between growth and residence time.
Efecto de la melaza, ácido fórmico y tiempo de fermentación sobre el pH y temperatura en microsilos de Leucaena leucocephala
Betancourt,M; Martínez de Acurero,M; Clavero,T; Razz,R; Pietrosemoli,S; Araujo-Febres,O;
Revista de la Facultad de Agronomía , 2003,
Abstract: a trial was conducted in very dry tropical forest located in san francisco county in zulia state, venezuela in order to evaluate the effect of molasses, formica acid and fermentation time on the ph and temperature of microsilos of leucaena leucocephala. a factorial arrangement (3x3x 8) with two replications was used, three levels of molasses (0; 2.5 and 5%), three levels of formic acid (0; 0.25 and 0.5%) and eight fermentation times (10, 21, 27, 34, 41, 48, 55 and 62 days). there were significant differences (p<0.05) for the interaction molasses x fermentation time, acid x fermentation time and acid x molasses on ph and temperature. the lowest values of ph (4.3; 4.4 and 4.36) were observed with 5% molasses and 27 days; 0.5% formic acid x 27 days and 2.5% molasses x 0.25% formic acid, respectively. the lowest values of temperature (26.27; 26.22 and 28.2°c) were obtained with 0% molasses 21 days ; 0.5% acid x 21 days and 2.5% molasses x 0.5% formic acid. addition of molasses and formic acid were positive in all treatments. the temperature values obtained in the microsilos were within the optimum range (20-30°c). in all treatments, ph values were consistent between 27 and 41 days. the results indicate that the methods employed were efficient conservation processes as demonstrate by the low values of ph and temperature reached in the microsilos of the l. leucocephala which are considered to be within optimum ranges.
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