Drying characteristics of non-centrifugal sugar

Abstract

Non-centrifugal sugar (NCS), generally known in most parts of Asia as jaggery, is a commonly used sweetener in food preparations. Sun drying of NCS has been reported to improve its shelf life. However, there is no systematic study, supported by relevant data and analysis, for this claim. In this article, the influence of temperature and relative humidity (RH) of the medium on the drying rate of jaggery is studied. The optimum drying temperature and humidity for jaggery of different compositions are determined. Jaggery containing low levels of reducing sugars (RSs) (2–5%) has lower equilibrium moisture content (EMC). For this reason, moisture could be reduced to as low as 0.5% within 250 minutes. Case-hardening is realized for the product with low RS content (typically ≤ 6%), and it does not allow one to employ high temperatures for drying. For jaggery containing high RS (10–15%), case-hardening was not evident, while the higher EMC does not permit moisture reduction below 4–5% under otherwise similar conditions.

Keywords:

• Drying
• jaggery
• reducing sugars
• case-hardening
• relative humidity

Conflict of interest

The authors declare that they have no conflict of interest.

Acknowledgements

The authors thank the Tata Centre for Technology and Design, IIT Bombay for financial support. They also thank Mr. Vishwambhar Patil, Mr. Rohit Kumbhar, Mr. Arjun Prajapati, and Ms. Yamini Jadhav for their support in conducting the experiments.

Additional information

Funding

This work was supported by the Tata Centre for Technology and Design IIT Bombay.