Full Length Research Paper

Integrated agrotechnology with preharvest ComCat^® treatment, modified atmosphere packaging and forced ventilation evaporative cooling of carrots

Tilahun Seyoum Workneh*, G. Osthoff and M. S. Steyn

The University of the Free State, Faculty of Natural and Agricultural Science, Department of Microbial, Biochemical and Food Biotechnology, P. O. Box 339, Bloemfontein 9300, South Africa.

*Corresponding author. E-mail: tilahun_seyoum@yahoo.com.

Accepted 23 July, 2009

   Abstract

Preharvest ComCat^® treatment of carrots was investigated for storage characteristics of treated vegetables in forced ventilation evaporative cooling. The forced ventilation evaporative cooling system was designed such that the temperature could be reduced by 8.4 - 13.4°C below ambient temperature, while maintaining a relative humidity up to 91%. Storage in this EC increased shelf lives of carrots to 24 days, compared to 4 days when stored at ambient conditions. ComCat^® treatment of carrots significantly (P ≤ 0.05) affected pH, total sugar content and the population of moulds and yeasts during storage at evaporative cooling. Modified atmosphere packaging significantly (P ≤ 0.001) reduced physiological weight loss, moisture and juice content of carrots stored inside evaporative cooling. Modified atmosphere packaging coupled with evaporative cooling reduced the rate of sugar utilization for metabolic activities, compared to unpackaged carrots stored at ambient conditions. The populations of aerobic bacteria and fungi were significantly (P ≤ 0.001) affected by modified atmosphere packaging coupled with evaporative cooling temperature. Disinfecting with chlorinated water helped additionally to limit microbial growth during evaporative cooling storage.

Key words: ComCat^®, modified atmosphere packaging, evaporative cooling, temperature, relative humidity, carrot.