Influence of glazing of direct solar drier on final product quality

Bc. Vojtěch Marek

Master's thesis

Abstract:

The Sun has a high energy potential in many disciplines. Over the human history, there is a challenge of food insecurity. Solar drying is an effective way of post-harvest processing to preserve food and increase the storage time of the product. In comparison to the traditional open sun drying, solar drying has many advantages in protection against external factors and allows drying the product faster and more effectively in order to prevent the food from microorganism growth. Nearly 80 % of agriculture production comes from small-scale farmers of so-called developing countries. These primary producers are indeed often struggling with food insecurity. In consequences to deal with the food insecurity, increasing product quality is a key issue for them. That brings us to focus on solar drying technologies, in its simplest way of direct passive solar drier, of economically reasonable effective process. The colour is among primary quality indicators recognized by potential consumers and thus plays crucial role in the drying process.The colour of indirect passive solar drying technology was measured under different glazing materials (Glass, Polycarbonate, PP foil and Plexiglas of 0, 75 %, 89 % and 75 % of UV transparency, respectively) to determine effect of UV irradiation on colour of apple slices. The measurements were done in the Czech Republic during August 2015 and 2016. The results are showing typical appearance of so-called Maillard reaction related to correlation between temperature and Browning Indicator. Correlation showed that the effect of Temperature on Browning Index is significant, p = .000 and strong (Pearson's p between 0.84 and 0.96). The PP foil glazing with the lowest inside temperature had the lowest Browning Index difference measured. These results suggest that the UV-B light does not have significant effect on colour change and therefore does not affect the quality of the dried product, in means of colour quality indicator.

Keywords

solar drier, drying, browning index, product quality, glazing

Language used: English

Date on which the thesis was submitted / produced: 27. 4. 2017

Thesis defence

• Supervisor: doc. Ing. Jan Banout, Ph.D.

Czech University of Life Sciences Prague

Faculty of Tropical AgriSciences

Master programme / field:
Tropical Agriculture / Sustainable Rural Development in the Tropics and Subtropics