Mineral Properties and Dietary Value of Raw and Processed Stinging Nettle (Urtica dioica L.)
Table 2
Proximate composition, vitamins, minerals, and fatty acid profile of raw and processed stinging nettle (Urtica dioica L.) shoots harvested from field plots in the fall of 2011 and spring of 2012.
Fall 2011
Spring 2012
Raw
Blanched
Cooked
Cooked + salt
Raw
Blanched
Cooked
Cooked + salt
Proximate analysis
Moisture (%)
89.0 ± 1.4a
87.2 ± 0.9a
87.7 ± 0.7a
88.6 ± 0.5a
75.1 ± 1.5c
84.6 ± 2.5b
85.6 ± 0.8b
91.7 ± 0.9a
Protein (%)
3.7 ± 0.5a
3.6 ± 0.4ab
3.6 ± 0.3a
2.7 ± 0.2b
6.3 ± 0.3a
4.1 ± 0.2b
3.8 ± 0.3b
2.2 ± 0.2c
Fat (%)
0.6 ± 0.1a
0.4 ± 0.1b
0.4 ± 0.0b
0.2 ± 0.0b
1.4 ± 0.3a
1.1 ± 0.1a
1.1 ± 0.2a
0.6 ± 0.1b
Ash (%)
2.1 ± 0.3a
1.8 ± 0.3ab
1.5 ± 0.3b
1.5 ± 0.1b
3.4 ± 0.2a
1.4 ± 0.1b
1.2 ± 0.1c
1.0 ± 0.1c
Fiber, total dietary (%)
6.4 ± 0.4a
4.2 ± 0.1b
3.5 ± 0.3c
3.6 ± 0.3bc
9.7 ± 1.0a
5.4 ± 0.9b
4.9 ± 1.0b
4.2 ± 0.2c
Carbohydrates, total (%)
7.1 ± 1.7a
6.6 ± 1.4ab
6.3 ± 0.8b
6.2 ± 1.2b
16.5 ± 1.6a
8.9 ± 0.7b
8.1 ± 1.1b
4.2 ± 0.6c
Other carbohydrates (%)
2.7 ± 0.2ab
2.9 ± 0.3a
2.5 ± 0.1b
2.7 ± 0.1a
6.2 ± 1.0a
3.5 ± 0.7b
3.3 ± 0.5b
2.0 ± 0.1c
Calories, total (kcal/100 g)
45.7 ± 3.1a
42.6 ± 2.1a
44.7 ± 2.5a
36.5 ± 2.3b
99.7 ± 2.5a
62.0 ± 1.0b
57.3 ± 1.5c
32.0 ± 1.0d
Calories from fat (kcal/100 g)
5.0 ± 1.0a
4.3 ± 0.6ab
2.7 ± 0.5bc
2.3 ± 0.6c
12.3 ± 1.6a
10.0 ± 1.0ab
8.7 ± 3.1b
4.0 ± 1.0c
Vitamins and minerals
Vitamin A, total (IU/100 g)
4935 ± 104a
4851 ± 56a
4548 ± 53b
4362 ± 78b
11403 ± 1333a
6470 ± 222bc
6021 ± 90c
7872 ± 354b
Vitamin A, as β-carotene (IU/100 g)
5035 ± 213a
4689 ± 37b
4549 ± 130b
4062 ± 39c
7860 ± 460a
4811 ± 88b
5028 ± 65b
4154 ± 148c
Vitamin C (mg/100 g)
1.1 ± 0.1a
0.6 ± 0.1b
0.6 ± 0.1b
0.5 ± 0.1b
0.5 ± 0.0a
0.5 ± 0.0a
0.5 ± 0.0a
0.5 ± 0.0a
Calcium (mg/100 g)
278 ± 9c
441 ± 12a
376 ± 9ab
318 ± 52bc
788 ± 41a
464 ± 10b
430 ± 10b
316 ± 7c
Iron (mg/100 g)
1.2 ± 0.1c
1.8 ± 0.2b
2.6 ± 0.1a
2.5 ± 0.3a
3.4 ± 0.3a
2.1 ± 0.2b
2.1 ± 0.3b
1.6 ± 0.1c
Sodium (mg/100 g)
5.7 ± 0.1b
6.3 ± 0.4b
6.5 ± 0.3b
87.7 ± 6.0a
5.5 ± 0.6b
7.0 ± 0.2b
6.7 ± 0.2b
81.1 ± 2.9a
Fatty acid profile
Saturated fat (%)
35.5 ± 2.6a
25.7 ± 2.5b
c
21.7 ± 1.9d
32.7 ± 2.8a
16.5 ± 1.5bc
17.3 ± 1.2b
15.7 ± 1.4c
Monounsaturated (%)
2.7 ± 0.2c
3.3 ± 0.2a
4.8 ± 0.3a
3.2 ± 0.1b
7.5 ± 0.6a
5.3 ± 0.3b
5.8 ± 1.1b
4.6 ± 0.2c
Polyunsaturated (%)
61.8 ± 3.5c
71.0 ± 2.0b
71.6 ± 1.2c
75.1 ± 1.9a
59.8 ± 2.7d
78.2 ± 4.4b
76.9 ± 2.5c
79.7 ± 2.6a
Cholesterol (mg/100 g)
1.0 ± 0.0a
1.0 ± 0.0a
1.0 ± 0.0a
1.0 ± 0.0a
1.0 ± 0.0a
1.0 ± 0.0a
1.0 ± 0.0a
1.0 ± 0.0a
Mean () ± standard deviation. Values within a year followed by different letters are significantly different at (Tukey’s HSD).