80 research outputs found

    Microbial Protein Production from Candida tropicalis ATCC13803 in a Submerged Batch Fermentation Process

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    Background and Objective: Microbial protein production can resolve one of the major world challenges, i.e. lack of protein sources. Candida tropicalis growth was investigated to specify a medium to reach the highest cell proliferation and protein production.Material and Methods: Fractional factorial design and the index of signal to noise ratio were applied for optimization of microbial protein production. Optimization process was conducted based on the experimental results of Taguchi approach designs. Fermentationwas performed at 25oC and the agitation speed of 300 rpm for 70 h. Ammonium sulfate, iron sulfate, glycine and glucose concentrations were considered as process variables. Optimization of the culture medium composition was conducted in order to obtain the highest cell biomass concentration and protein content. Experiment design was performed based on the Taguchi approach and L-16 orthogonal arrays using Qualitek-4 software.Results and Conclusion: Maximum biomass of 8.72 log (CFU ml-1) was obtained using the optimized medium with 0.3, 0.15, 2 and 80 g l-1 of ammonium sulfate, iron sulfate, glycine and glucose, respectively. Iron sulfate and ammonium sulfate with 41.76% (w w-1) and 35.27% (w w-1) contributions, respectively, were recognized as the main components for cell growth. Glucose and glycine with 17.12% and 5.86% (w w-1) contributions,respectively, also affected cell production. The highest interaction severity index of +54.16% was observed between glycine and glucose while the least one of +0.43% was recorded for ammonium sulfate and glycine. A deviation of 7% between the highestpredicted cell numbers and the experimented count confirms the suitability of the applied statistical method. High protein content of 52.16% (w w-1) as well as low fat and nucleic acids content suggest that Candida tropicalis is a suitable case for commercial processes.Conflict of interest: The authors declare that there is no conflict of interest

    Utjecaj djelomične zamjene šećera sirupom od smokava na preživljavanje bakterije Bacillus coagulans i fizikalno-kemijska svojstva probiotičkog sladoleda

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    Research background. Various sectors of the food industry demand the enrichment of food with functional compounds. Probiotic products with valuable nutritional and therapeutic properties have attracted great attention in the fields of industry, nutrition and medicine. The aim of the present study is to investigate the sensory and physicochemical properties of probiotic ice cream containing fig syrup and to evaluate the survival of Bacillus coagulans after 90 days of storage at -18 °C. Experimental approach. In this study, four experimental groups of ice cream were produced as follows: plain dairy ice cream (without additives), ice cream containing 109 CFU/g B. coagulans, ice cream containing 25 % fig syrup as sugar substitute and ice cream containing 25 % fig syrup as sugar substitute and 109 CFU/g B. coagulans. They were stored at -18 °C for 3 months. Texture, pH, acidity and viscosity were analysed and microbial counts were determined after 1, 30, 60 and 90 days of storage. The organoleptic evaluation was carried out on days 1 and 90. Results and conclusions. The results showed that during the initial freezing process and the transformation of the mixture into ice cream, the number of B. coagulans decreased from 109 to 107 CFU/g, without significant changes observed over the 90-day period. No significant changes were found in the sensory and textural properties of the samples either. Replacement of 25 % sugar with fig syrup reduced the pH, increased the acidity of the ice cream and improved their viscosity. In conclusion, the production of functional ice cream using fig syrup and B. coagulans is recommended for their health benefits. Novelty and scientific contribution. The results of this study can be used to prepare functional and healthy foods. Our results suggest that fig syrup has the potential to be used as a natural sweetener or sugar substitute in various products.Pozadina istraživanja. U različitim se granama prehrambene industrije pojavila potreba za obogaćivanjem hrane funkcionalnim sastojcima. Probiotički proizvodi s vrijednim hranjivim i terapeutskim svojstvima su od velikog interesa za prehrambenu industriju, nutricionizam i medicinu. Svrha je ovoga rada bila ispitati senzorska i fizikalno-kemijska svojstva probiotičkog sladoleda koji sadržava sirup od smokve, te procijeniti preživljavanje bakterije Bacillus coagulans u dobivenom sladoledu nakon 90 dana skladištenja pri -18 °C. Eksperimentalni pristup. U ovom su istraživanju pripremljene četiri skupine sladoleda, i to: obični mliječni sladoled bez dodataka, sladoled s dodatkom 109 CFU/g bakterije B. coagulans, sladoled s dodatkom 25 % sirupa od smokava kao zamjenom za šećer i sladoled s dodatkom 25 % sirupa od smokava i 109 CFU/g bakterije B. coagulans. Svi su uzorci skladišteni na –18 °C tijekom 3 mjeseca. Ispitani su sljedeći parametri: tekstura, pH-vrijednost, kiselost i viskoznost dobivenih sladoleda, a broj je mikroorganizama određivan nakon 1, 30, 60 i 90 dana skladištenja. Organoleptičko ispitivanje je provedeno tijekom prvog i devedesetog dana skladištenja. Rezultati i zaključci. Rezultati pokazuju da se tijekom prve faze zamrzavanja smjese i nastanka sladoleda broj bakterija B. coagulans smanjio s 109 na 107 CFU/g, te se nakon toga nije mijenjao tijekom 90 dana skladištenja. Također nisu uočene bitne promjene senzorskih svojstava niti teksture uzoraka. Zamjenom 25 % šećera sirupom od smokava smanjila se pH-vrijednost, a povećala kiselost te poboljšala viskoznost sladoleda. Zaključno, možemo preporučiti proizvodnju funkcionalnog sladoleda s dodatkom sirupa od smokve i bakterijom B. coagulans zbog njihovog pozitivnog učinka na zdravlje. Novina i znanstveni doprinos. Dobiveni rezultati mogu se primijeniti u pripremi funkcionalne i zdrave hrane. Naši rezultati pokazuju da bi se sirup od smokava mogao koristiti kao prirodni zaslađivač ili zamjena za šećer u različitim proizvodima

    On sign-symmetric signed graphs

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    A signed graph is said to be sign-symmetric if it is switching isomorphic to its negation. Bipartite signed graphs are trivially sign-symmetric. We give new constructions of non-bipartite sign-symmetric signed graphs. Sign-symmetric signed graphs have a symmetric spectrum but not the other way around. We present constructions of signed graphs with symmetric spectra which are not sign-symmetric. This, in particular answers a problem posed by Belardo, Cioabă, Koolen, and Wang (2018)

    Association between health-related quality of life and impaired glucose metabolism in Iran: The Qazvin Metabolic Diseases Study

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    Aim To evaluate the association between health-related quality of life and glucose metabolism status in a study population in Qazvin, Iran. Methods This cross-sectional study was conducted in 1044 people (aged 20–78 years old) between September 2010 and April 2011 in Qazvin, Iran. An oral glucose tolerance test was performed for each participant who had never been diagnosed with diabetes. Participants were characterized as having normal glucose metabolism, pre-diabetes or diabetes according to American Diabetes Association criteria. The short-form 36 questionnaire was used to measure quality of life. Data were analysed using a chi-squared test, ANOVA and ANCOVA. Results A total of 530 (51.7%) of the participants were women, and 24.1 and 11.6% of the participants were categorized as having prediabetes and diabetes mellitus, respectively. Except for the role emotional domain, there was a gradual decrease in the mean scores of every domain of the short-form 36 scale across the three study groups. The mean scores in the physical domains were significantly different among the participants with normal glucose metabolism and those with diabetes. After adding age as covariate, there were no significant differences between the categories in any of the domains. Conclusion There is no association between quality of life domains and glucose metabolism status in Iranian subjects. More longitudinal studies are necessary to investigate the natural history of pre-diabetes, diabetes and quality of life. Diabet. Med. 31; 754–758 (2014

    Oxford-MEST classification in IgA nephropathy patients: A report from Iran.

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    BACKGROUND There is a limited knowledge about the morphological features of IgA nephropathy (IgAN)in the middle east region. OBJECTIVES The objective of this study was to evaluate the spectrum of histopathological findings in IgAN patients at our laboratory. PATIENTS AND METHODS At this work, an observational study reported which was conducted on IgAN patients using the Oxford-MEST classification system. RESULTS In this survey, of 102 patients 71.6 % were male. The mean age of the patients was 37.7 ± 13.6 years. Morphologic variables of MEST classification was as follows; M1: 90.2 %, E: 32 %, S: 67 % also,T in grads I and II were in 30% and 19% respectively, while 51% were in grade zero. A significant difference was observed in segmental glomerulosclerosis (P=0.003) and interstitial fibrosis/tubular atrophy frequency distribution (P= 0.045), between males and females . Furthermore, it was found that mesangial hypercellularity was more prevalent in yonger patients. Moreover, there was a significant correlation between serum creatinine and crescents (P<0.001). There was also significant correlation of serum creatinine with segmental glomerulosclerosis (P<0.001). CONCLUSIONS Higher prevalence of segmental glomerulosclerosis and interstitial fibrosis/ tubular atrophy, as the two of, four variables of Oxford-MEST classification of IgAN in male patients further attests that male gender is a risk factor in this disease.In this study the significant correlation between serum creatinine and crescent was in an agreement with previous studies and suggests for the probable accomodation of extracapillary proliferation as a new variable in MEST system
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