Ultrasound and microwave assisted extraction of ergosterol from Agaricus bisporus L.: optimization through response surface methodology

There is scientific evidence demonstrating the benefits of mushrooms ingestion due to their richness in bioactive compounds such as mycosterols, in particular ergosterol [I]. Agaricus bisporus L. is the most consumed mushroom worldwide presenting 90% of ergosterol in its sterol fraction [2]. Thus, it is an interesting matrix to obtain ergosterol, a molecule with a high commercial value. According to literature, ergosterol concentration can vary between 3 to 9 mg per g of dried mushroom. Nowadays, traditional methods such as maceration and Soxhlet extraction are being replaced by emerging methodologies such as ultrasound (UAE) and microwave assisted extraction (MAE) in order to decrease the used solvent amount, extraction time and, of course, increasing the extraction yield [2]. In the present work, A. bisporus was extracted varying several parameters relevant to UAE and MAE: UAE: solvent type (hexane and ethanol), ultrasound amplitude (50 - 100 %) and sonication time (5 min-15 min); MAE: solvent was fixed as ethanol, time (0-20 min), temperature (60-210 •c) and solid-liquid ratio (1-20 g!L). Moreover, in order to decrease the process complexity, the pertinence to apply a saponification step was evaluated. Response surface methodology was applied to generate mathematical models which allow maximizing and optimizing the response variables that influence the extraction of ergosterol. Concerning the UAE, ethanol proved to be the best solvent to achieve higher levels of ergosterol (671.5 ± 0.5 mg/100 g dw, at 75% amplitude for 15 min), once hexane was only able to extract 152.2 ± 0.2 mg/100 g dw, in the same conditions. Nevertheless, the hexane extract showed higher purity (11%) when compared with the ethanol counterpart ( 4% ). Furthermore, in the case of the ethanolic extract, the saponification step increased its purity to 21%, while for the hexane extract the purity was similar; in fact, hexane presents higher selectivity for the lipophilic compounds comparatively with ethanol. Regarding the MAE technique, the results showed that the optimal conditions (19 ± 3 min, 133 ± 12 •c and 1.6 ± 0.5 g!L) allowed higher ergosterol extraction levels (556 ± 26 mg/100 g dw). The values obtained with MAE are close to the ones obtained with conventional Soxhlet extraction (676 ± 3 mg/100 g dw) and UAE. Overall, UAE and MAE proved to he efficient technologies to maximize ergosterol extraction yields.

Using importance-satisfaction analysis in evaluating student satisfaction: a case study of economics and administration Faculty of Qafqaz University

Education is one of the main industries in the world, which needs to focus more than other types of industries. As Mandela said, “Education is the most powerful weapon, which you can use to change the world” (www.brainyquote.com). Global economic recession era put serious pressure on private Higher Education Institutions (HEI), which resulted as decrease in the university spending`s budget. Therefore, HEI forced to develop more competitive ways to find new financial resources for rapid technological and organizational changes (Savsar, 2012). Students are the motive of being of Higher Education. The aim of this study is to implement İmportance-Satisfaction Analysis (IPA) matrix to evaluate the student`s satisfaction and assess importance of different attributes in terms of student`s perception. The students that participated in this study enrolled in the present academic year, 2015/2016, in the Economics and Administration Faculty-Qafqaz University. In order to perform study, survey method applied to collect the data and number of received valid questionnaire were 266. Questionnaire used to collect demographic information of students, identify importance given to each attribute and satisfaction degree of each attribute. Descriptive analysis used to identify profile of respondents, also find satisfaction and importance degree for each attributes. To evaluate differences between groups, built association between variables, find relation between variables and answering to the research hypothesis inferential analysis applied. Moreover, IPA matrix was been used to explore the attributes that needs improvement that perceived as attributes that are more important for the students. The result showed that generally students are satisfied with service quality offered by HEI-on sample of the Qafqaz University. In addition, research found that there are no differences in overall satisfaction and importance by department, gender, academic year and grade point average. IPA matrix highlighted the main attributes, which performs well, namely Academic Services and Teaching aspects, and in another hand needs to concentrate in Undergraduate program and External Relations. In addition, research found that loyalty of students is very low and there is a negative correlation between loyalty and satisfaction.