Nour Zien Alabiden (1) *, Ramdan Utra(1) and Mohamed Massri (1)
(1). Department of Food Engineering, Faculty of Chemical and Petroleum Engineering, Al-Baath University, Homs, Syria.
(*Corresponding author:Eng. Nour Zien alabiden. E-Mail: noor.zien@gmail.com)
Received: 7/07/2021 Accepted: 9/08/2021
Abstract
Apples are dried and used as snacks because they are rich in phenolic compounds, antioxidants, ascorbic acid, minerals and vitamins. Therefore, this research aimed to study the effect of the direct solar drying process and the indirect solar drying, by used of a hybrid solar dryer that was designed in this study, on the moisture content of apple slices, water activity, ascorbic acid, phenolic compounds, color change, and the effect of storage the dried product for a period of six months. These indicators were estimated during six storage periods (0, 15, 30, 60, 120 and 180 days). The results showed a significant (p<0.05) increase in moisture content in the slices dried by direct solar drying from 14.517% at the beginning of storage to 17.521% at the end of storage, while in the hybrid dryer from 11.218% at the beginning of storage to 14.209% at the end of storage, it also increased The values of the water activity were significant by direct drying from 0.431 at the beginning of storage to 0.511 at the end of storage and in the hybrid dryer from 0.318 to 0.425. All color parameters changed significantly during storage depending on the drying method. The results showed that the color of the sample dried using the hybrid dryer was better and closer to the fresh sample. A decrease in the content of ascorbic acid was observed from the beginning of storage to its end by direct drying from 45.296 mg/100 g to 22.5 mg/100 g dry weight, and in the hybrid dryer from 65,741 mg/100 g dry weight to 32.5 mg/100 g dry weight. The total phenol content decreased significantly from the beginning to the end of storage. The results showed that the moisture content was lower with the hybrid dryer by 3.299% compared with direct solar drying, and the product retained better color and higher content of ascorbic acid and total phenols and thus better quality compared to direct solar drying.
Key words: solar drying, dried apple, hybrid dried, ascorbic acid, total phenols
Full paper in Arabic: pdf