Evaluation of the quality criteria of freeze dried chestnut produced for enrichment of breakfast cereal products

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In this study, the quality criteria of freeze dried chestnut produced for enriching the breakfast cereal products were evaluated. The peeled and frozen chestnut was used as a raw material which is obtained from Bozdağ İtimat Şekerleme İmalat San. Tic. Ltd. in İzmir –Ödemiş. The product was dried by applying freeze drying method in different parboiling times (10, 15, 20 min.), different slice thicknesses (3, 4,5, 6mm), different plate temperatures (0, 15, 30 0C). In order to evaluate the quality criteria of the product obtained at the end of the drying process another product was obtained by tray drying method which is expected to represent traditional drying method.
According to the results of analysis moisture content and water activity which are effective on a shelf life were at acceptable levels in all trials. The color of the samples obtained by freeze drying method were not get dark however it was observed that unacceptable color development occurred in tray drying is undesirable for breakfast cereals. It was determined that the bulk density is affected by the drying method. The bulk density of chestnuts dried by tray dryer with high moisture content were low, at the same time the bulk density of freeze dried chestnuts were affected by different process conditions. According to the results of rehydration analysis, the rehydration capacity with milk which was kept in refrigeration temperature was higher than the rehydration capacity with milk at room temperature.
Texture analysis was also applied to the products obtained by freeze drying method and tray drying method. The results of this analysis showed that, the obtained product was not hard in structure but compared with tray dried product the required crunchy and crispy structure was obtained. The results of analysis of samples which were dehydrated with freeze drying method and tray drying method were supported by the results of Macro pictures and SEM analysis.

Elif Yurdakul
Kahvaltılık gevrekleri zenginleştirmek amacıyla üretilen dondurarak kurutulmuş kestanenin kalite kriterlerinin değerlendirilmesi · 2008 · 189 sayfa.
Danışman: Yrd. Doç. Dr. S. Nur Dirim
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