The freeze drying is a suitable dehydration process for saffron that contains heat‐sensitive volatile and aroma‐yielding compounds such as crocin (act as a coloring agent), picrocrocin (responsible for the taste) and safranal (volatile oil that gives characteristic odor and aroma). The heat‐sensitive volatile and aroma‐yielding compounds of saffron can be more preserved using freeze drying in comparison with other conventional drying methods. In this study the freeze‐drying characteristics of saffron was determined experimentally. The drying kinetics data were fitted to 10 different empirical diffusion drying models from literature to find the best model that represents the weight loss of saffron during the freeze drying. Among the models tested in this study, the Page model was found to be the best model in representing the drying kinetics of saffron during the freeze drying. Effective diffusivity found as 1.62 × 10−11 m2/s.
Practical Applications
Saffron, which has been intensively used for flavoring and coloring foods, dying textile and medical purposes since ancient times, is the most precious and expensive agricultural product in the world. Freeze drying, which is both slow and expensive, is the method of separation for high market value products. It has been shown that freeze drying can be used for dehydration of saffron with minimum safranal (main aroma component) and crocin (coloring agent) loss. High cost of freeze drying of saffron can be compensated by minimum loss of safranal and crocin contents in the final product. It is crucial to know the drying kinetics of saffron to determine the drying time under certain conditions. In this work, the freeze‐drying kinetics of saffron were studied and the best empirical model that represents the weight loss of saffron during the freeze drying and effective diffusivity were determined.
The generation of electrical energy with photovoltaic modules is a highly useful and environmentally friendly method. For this reason, studies to increase the electrical energy production from photovoltaic (PV) modules have gained great importance. Concentrated PV systems constitute a significant part of these studies. The major problems with the concentrated PV systems are the risks of lowering the efficiency of the cells (i.e., concentration process increases PV cell temperature) and the thermal damage that can occur with sudden temperature increases. In order to avoid these risks, various applications are used to cool concentrated PV modules. In this study, an active system, which was developed for cleaning and cooling PV modules, was tested. The aim of the present study was to ensure that the surfaces were clean and free of external, contaminating factors such as dust and dirt, and that the PV cells were cooled. During the experiments, two different systems were compared: the system with the cleaning‐cooling processes and the one without these processes. Prior to starting experiments, a hydrophobic liquid onto the surfaces of the PV modules was applied to facilitate the cleaning process. The results of the experiments revealed that the temperature of the PV module was 50°C in the cleaning‐cooling process and 67°C in the system without the cleaning‐cooling process. On the other hand, it was observed that the proposed design increased the power output of PV module up to 40%.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.