The Effect of Drying on the Nutritional Properties of Ginger (Zingiber officinale rosc.)

Abstract

The effects of drying as a processing technique on ginger were investigated with respect to the proximate composition of the produce. Matured ginger rhizomes (variety UG1 also known as Yatsun – biri) were collected, graded and sorted into three (3) groups of equal weights with sample codes A, B and C. Sample A was left unprocessed (fresh) while samples B and C were dried using the Oven and Sun drying methods respectively to a specified percentage weight loss of between 90 – 95% after which the three (3) samples were taken to the lab and their proximate compositions determined. The Oven-dried process took a total period of 13hours and the percentage weight loss was found to be 90.18% while the Sun-drying process took a total period of 5days (12hours per day) and the percentage weight loss of the rhizomes was 90.95%. The Analysis of the proximate composition results showed that the moisture content, lipid content and carbohydrate content of ginger reduced after drying while the Ash and Protein contents increased. The Crude Fibre content of fresh ginger increased after Oven drying and reduced after Sun drying. The moisture, lipid and carbohydrate contents of the Oven-dried ginger were 7.93%, 10% and 46.74% respectively, and these were found to be lesser than those of the Sun-dried ginger which were 10.83%, 11.33% and 63.03% respectively. On the other hand, the Ash content, Crude Fibre content and Crude Protein content of the Oven-dried ginger were 13.77%, 17.63% and 12.46% respectively and these were found to be greater than those of the Sun-dried which were 7.73%, 6.6% and 11.25%. Thus based on the results obtained in the research, it can be seen that in the drying of ginger rhizomes, not only the moisture of the produce is affected other nutritional parameters are also affected due to the presence of volatile and heat sensitive compounds in the produce; the Oven-drying technique however is a better option for the drying process as it is more effective in removing sufficient moisture and also enhances some nutritional parameters of the produce however the sun-drying technique remains a better option for the extraction of ginger oil.