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

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

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

Examining the Role of Language, Emotion, and Culture as Three Basic Needs in Intercultural Communication Based on Iranian Language Teachers' Viewpoints

Pinpointing the role of language, emotion, and culture in intercultural interactions as the three basic needs of intercultural interactions is one of the most important problems in the intercultural field. Therefore, this paper probed the role of language, emotion, and culture simultaneously in intercultural communication in Iran. By using convenience sampling, one hundred Iranian language teachers were chosen and their language proficiency and ICC levels were specified by using Oxford Placement Test (OPT) and intercultural communicative competence (ICC) questionnaire. Then, the researchers used exploratory factor analysis (EFA) to classify ICC questions under language, emotion, and culture categories.  After classifying the questions, the researchers used confirmatory factor analysis (CFA), standard solution coefficient, standard path coefficient, T value, and Sobel formula to analyze the collected data from the ICC questionnaire based on participants' answers. The results revealed that language, culture, and emotion were the main macro-elements of intercultural communication. Also, it was shown that language was the most important need and macro-element in intercultural communication and then the second and third place went to culture and emotion respectively.  It was found that emotion acted as a mediator variable between language and culture and there was a relationship among language, culture, and emotion, too. This study was of high importance for language teachers, curriculum designers, textbook writers, intercultural experts, and cultural psychologist

Determining Optimal Lot Size, Reorder Point, and Quality Features for a Food Item in a Cold Warehouse: Data-Driven Optimization Approach

We propose a nonlinear optimization model for determining the optimum lot size and reorder point for a food item distributed through a cold warehouse as well as the optimum quality features, namely temperature, humidity, packaging type, and level of environmental conditions. The item's quality is estimated based on the features mentioned earlier, and then it is used as a constraint in the optimization process. An assumption was made that the inventory is managed under a continuous review policy and the warehouse has limited space. The model seeks to minimize the annual total cost of managing the warehouse. The model will be a nonlinear mixed programming one, which is solved by Pyomo as a leading library in Python language programming. Numerical examples are used to demonstrate the use of the model and, through sensitivity analysis, develop insights into the operation of cold warehouses. This sensitive analysis opens the doors to managerial insight from which managers and policymakers can highly benefit.Comment: 12 pages, 5 figure

On sign-symmetric signed graphs

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

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