Effect Of Drying Method On Theantioxidant, Phytochemical, Antinutrient And Selected Chemical Properties Of Turmeric Powder

Abstract

Listen

Translate article

Background: Turmeric (Curcumin longa) is one of the known spices that have culinary uses as well as medical and medicinal uses. It is a golden spice derived from the rhizome of curcuma longa plant which belongs to the family of Zingiberaceae. Turmeric is a therapeutic plant that is consumed as a flavouring, preservative and colouring agent. Turmeric has anti-inflammatory, antioxidant and phytochemical properties. The main active ingredient in turmeric is curcumin. Curcumin has free radical scavenging properties. Despite the health benefits of turmeric, few people use it partly because of the cumbersomeness of the preparation, staining and drying out of the tubers during storage. This study produced turmeric powder and evaluated the effect of drying method on the antioxidant, phytochemical, antinutritional and chemical properties of the products in view of ascertaining the best processing method in terms of nutrient retention. Materials and Methods: In this randomized controlled study, three kilograms (3 kg) of turmeric rhizome were cleaned, peeled, sliced thinly and shared into three equal parts. One part was shade dried for 5 days, the second, sun dried for 48 h and the third oven dried at 55±10C for 6 h. The dried samples were milled separately and analyzed for antioxidants (curcumin, beta carotene, vitamins C and E), phytochemicals (flavonoids, total phenol, saponin and alkaloids), antinutrients (phytate, tannin and oxalate) and some chemical properties (moisture, fat, calcium, iron, zinc and iodine). Data obtained were analyzed statistically using one way analysis of variance and means separated using Duncan new multiple range test. Significance was accepted at 5 % probability (p<0.05). Results: The beta carotene, vitamin C, E and curcumin contents were high ranging from 24.54 to 27.78, 662.24 to 1397.55, 12.54 to 17.88 and 16.39 to 17.89 mg/100g, respectively, suggesting antioxidant potential of turmeric. The high flavonoid content (7.23 to 9.28 %) indicated that turmeric may have inhibitory activity against disease causing organisms and may act as biological response modifier. The low values of alkaloid and saponin obtained maybe an indication of potency of the product. The low values of phytate (0.88 to 1.1 2 %), tannin (2.02 to 3.96 %) and oxalate (0.15 to 0.20 %) are suggestive of high nutrient bioavailability. The samples exhibited low calcium, iron, zinc, and high iodine values (1.01 to 1.63 %, 0.20 to 0.31, 1.27 to 3.11 and 7.27 to 25.86 percent respectively. Significant (p<0.05) variations existed among the values indicating drying techniques influence. Conclusion: The results obtained from the study showed that method of drying has significant effect on the parameters analyzed. Sun drying or shade drying are preferred for turmeric powder processing.