Study effect of drying conditions in cabinet dryer on drying rate of grape and quality of raisin

مجله پژوهشهای علوم و صنایع غذایی ایران

Article 12, Volume 12, Issue 2 - Serial Number 38, May and June 2016, Pages 226-238   

Document Type: Research Article

DOI: 10.22067/ifstrj.v1395i2.32219

Authors

Azam Ayoubi^{* 1}; Nasser Sedaghat²; Mahdi Kashani-Nejad³; Mohebbat Mohebbi²; Mehdi Nasiri mahalati⁴

¹Kerman University

²Department of Food Science and Technology, Ferdowsi University of Mashhad, Mashhad, Iran.

³Gorgan University of Agricultural Sciences and Natural Resources.

⁴Ferdowsi University of Mashhad, Mashhad, Iran.

Abstract

The purpose of this research was study effect of drying conditions (temperature at three levels of 60,70, and 80 oC, air velocity at two levels of 1/5 and 2/5 m/s, and four pretreatments including potassium carbonate and paksan oil, olive oil, hot water and no pretreatment (control)) on drying grape process and quality of raisin including rehydration, shrinkage, hardness and browning index. The results showed that temperature, air velocity and pretreatment have significant effects on drying rate and quality of raisin. Drying rate increased with increasing temperature and air velocity and with application of preatreatment. The best values of hardness (0.73 N), shrinkage (81/04%) and the least value of browning index (0/157) were related to dried raisin at 60 oC and most value of rehydration (1/266) was related to dried raisin at 70 oC. Air velocity just significantly affected on browning index. Increasing air velocity decreased browning index. Also between used preatreatments , potassium carbonate and paksan oil caused best physicochemical results.

Keywords

Air velocity; Browning index; Drying; Drying rate; Raisin

References