Fruit Properties and Nutritional Composition of Some Walnut Cultivars Grown in Pakistan

Abstract

Walnuts (Juglans regia L.) are rich source of a number of important nutrients that have a very positive effect on the human health. In this study nuts of six different walnut cultivars grown in Pakistan namely Chitral-1, SW-1, Chitral-3, Chitral-2, SW-3 and Dir-2 were selected and evaluated for their physical properties, proximate and mineral composition. The nut length was found in the range of 35.17-41.37 mm, nut diameter (31.72 mm-34.32 mm), Nut thickness (32.21-35.10 mm), nut weight (10.30 g-19.22 g), Kernel weight (5.81 g-9.24 g), Kernel ratio (43.19-65.14%), shell thickness (0.81-1.35 mm), moisture content (2.76-4.20%), ash content (1.27-1.95%), fats (63.54-69.92%), protein (15.96-19.15%) and total carbohydrates (8.04-12.14%). Kernels of Dir-2 and Chitral-2 cultivars were determined to contain high protein content (>18% protein) while Chitral-1 and SW-1 contain high carbohydrates content of >10%. The energy value of the kernels of these cultivars was determined in the range of 698.10-732.44 Kcal/100 g, which shows that the fruits of these varieties are rich source of energy. In minerals the level of sodium is 40.9-64.5 ppm, K (3551-4827ppm), Ca (925-1250 ppm), Fe (30.08-41.20 ppm), Zn (11.75-25.5 ppm), Mg (1059-1765 ppm), Cu (1.96-2.75 ppm) and Pb (0.69-1.06 ppm). The fruit properties indicates that Chitral-3, Chitral-2 and SW-3 are superior walnut cultivars in terms of their physical properties than the rest of the cultivars and they could be cultivated and developed as standard varieties in Pakistan. Moreover, kernels of all the cultivars studied are rich in K, Ca, Mg, Na and Fe.