M.Sc. Tezi Görüntüleme

Student:	Erdoğan TİMURKAYNAK
Supervisor:	Prof. Dr. Mehmet Emin ARICI
Department:	Makine Mühendisliği
Institution:	Graduate School of Natural and Applied Sciences
University:	Karadeniz Technical University Turkey

Title of the Thesis:	Investigation of Heat and Mass Transfer During Hazelnut Roasting Process
Level:	M.Sc.
Acceptance Date:	21/6/2011
Number of Pages:	61
Registration Number:	i2380

Summary:

It is aimed in this study to investigate the effect of cooling parameters, such as temperature, relative humidity, coolant rate and cooling time, on the moisture content of roasted hazelnut. For this purpose, an experimental set up is developed and built to fit the requirements of a standard commercial oven and acts as a pilot unit. It fits the requirements of a standard commercial oven and acts as a pilot unit. In addition a standard commercial oven, the plot unit has some other features. It consists of a refrigeration unit to control temperature and the relative humidity of cooling air. The pilot unit also has ability of inducing air into chamber in different directions. For the roasting period, air is heated before it reaches the roasting chamber. Following the roasting period, the cooling period starts and the product remains within the roasting chamber during the both processes.

With the proposed system, roasting and after roasting cooling experiments are performed. Roasting of hazelnut has been carried out for seven different flow rates. Seven cooling flow rates are applied to the roasted hazelnut for each roasting flow rate. This set of experiment is repeated for three different cases: The first type of cooling is applied to the roasted hazelnut by using atmospheric air. The second type of cooling is applied to the roasted hazelnut by using cooled air. The third type of cooling is applied to the roasted hazelnut by using cooled and reheated air.

Change of moisture content ratio is determined by measuring the mass of certain amount of product before roasting and end of the cooling for each case. Dimensionless moisture content ratio varitions are obtained for each individual experiment and result are graphically presented for each case. The experimental results show that the controlled cooling air has significant effect on the moisture content of roasted hazelnut. It is concluded that lowering the relative humidity of cooling air decreases the moisture content of hazelnut. The magnitude of effect of relative humidity is also depending on the roasting flow rate, cooling flow rate and the duration of the cooling process.

Keyword: Hazelnut roasting, moisture content, cooling process