~ 255 ~ International Journal of Chemical Studies 2017; 5(5): 255-259 P-ISSN: 2349–8528 E-ISSN: 2321–4902 IJCS 2017; 5(5): 255-259 © 2017 IJCS Received: 08-07-2017 Accepted: 09-08-2017 Khan Chand Junior Research Officer, Department of Post-Harvest Process and Food Engineering, College of Technology, G. B. Pant University of Agriculture and Technology, Pantnagar-263145, U.S. Nagar, Uttarakhand, India Anupama Singh Professor, Department of Post- Harvest Process and Food Engineering, College of Technology, G. B. Pant University of Agriculture and Technology, Pantnagar-263145, U.S. Nagar, Uttarakhand, India Correspondence Khan Chand Junior Research Officer Department of Post-Harvest Process and Food Engineering, College of Technology, G. B. Pant University of Agriculture and Technology, Pantnagar-263145, U.S. Nagar, Uttarakhand, India Effect of process parameters on quality of dried nettle leaves Khan Chand and Anupama Singh Abstract Stinging nettle (Urtica dioica. L.) is a wild, unique herbaceous perennial flowering plant with stinging hairs. It has long history of use as a food source as a soup or curries, and also used as a fiber as well as medicinal herb. The current aim of present study was to analyze the effect of temperature and loading density on protein content and colour of dried nettle leaves. The present study was undertaken with different combinations of temperatures (55, 65 and 75 0 C) and loading density (0.5, 1 and 1.5 kg/m 2 ). The experimental data of quality parameters were fitted into polynomial model developed using Multilevel Categoric Design and checked the adequacy of model by calculating R 2 and Fisher values. The colour change (ΔE) was more evident as the temperature was increased but the protein content was found higher at lower temperature and high loading density. For getting the best results, the optimum values of temperature and loading density were obtained 55 0 C and 1.5 kg/m 2 . At these optimum values of process parameters, the colour change (ΔE) was found minimum (2.12) indicates that no deterioration in colour was observed while the protein content also was found maximum (2.78 mg/ml) which retained in dried nettle leaves. Keywords: nettle leaves, temperature, loading density, protein and colour 1. Introduction Stinging nettle (Urticadioica L., Urticaceae) is a weed plant widespread in the world, predominantly in wasteland areas with unpleasant stinging hair on the stems and leaves (Kavalali, 2003) [7] . Its genus name Urtica is derived from uro, to burn, or urere, meaning to sting given by Grieve, (1931) [6] . The stinging nettles species name dioica is Latin for "two houses", from the Greek word oikia, meaning house, and refers to the plant's dioecious nature, bearing male and female flowers on separate plants. Nettle leaf is a micronutrient dense, nutritious food; however, it should be steamed or cooked before ingestion to destroy the stinging hairs, which contain histamine, formic acid, acetylcholine, acetic acid, butyric acid, leukotrienes, 5-hydroxytryptamine, and other irritants (Wagner et al., 1994 and Emmelin, 1949) [14, 4] . When contact with the hairs leads to a mildly painful sting, development of an erythematous macule, and itching or numbness for a period lasting from minutes to days. Medicinal extracts of nettle do not cause this reaction as the hairs are destroyed in processing. Stinging nettle is a powerhouse of nutrients, contains on average 22% protein, 4% fats, 37% non-nitrogen extracts, 9- 21% fibre, and 19-29% ash. The leaves contain about 4.8 mg chlorophyll per gram of dry leaves, depending on whether the plant was grown in the sun or shade. Surprisingly, more chlorophyll and carotenoids are found in plants that are grown in the shade, and dried nettle leaves contains 40% protein (Vance, 2017; Umberto, 2012) [13, 12] . Nowadays, in form of leaves and roots extracts, stinging nettle is used as supportive therapy to help relieve rheumatic complaints and seasonal allergy symptoms in reducing difficulties in urination associated with early stages of benign prostatic hyperplasia (Roschek et al., 2009; Tanzil et al., 2002a) [10, 11] . Antimicrobial and antioxidant activities (Kukrić et al., 2012) [8] , the possibilities for decreasing of cardiovascular risks (Alisi et al., 2008) [2] and investigations of chemo preventive properties of stinging nettle extracts in breast cancer cells are still researched (Güler, 2003) [5] . Another research indicates household remedy usage in Moorish, stalk, and leaves of nettle used in treatment of diabetes, hypertension, astringent, anti-rheumatic, diuretic, antidiuretic, and cholagogue (Ziyyat et al., 1997) [15] . The study was focused on the effect of temperature and loading density to the quality of dried nettle leaves because dried leaves are processed for teas, tablets and capsules, and other preparations, and also results in retention significant quantity of proteins and other nutritional