Determination of Nutritional Value and Oxidative Stability of Fresh Walnut

Abstract

Walnut (Juglans regia L.) is a tree with significant economic value and usage for human health and various food industries. However, fresh walnut kernels are a less widespread product than the dried kernels. This study aimed to determine the fresh walnut kernel properties including, fatty acid composition, proximate composition, total phenolics (TPs), total antioxidant capacity (TAC), acidic, peroxide and saponification values of extracted oil and minerals of fresh walnuts kernels. Green walnut fruits were harvested on commercial maturity. The content of different fatty acids (%) was determined as 16:0; 5.91, 18:1; 77.7, 18.2; 11.13 and 18:3; 2.84. Also, the essential nutritional compounds such as protein content (16 ± 0.67), ash (3± 0.32), water (20 ± 0.49), fat (40 ± 0.22) and total carbohydrate (21 ± 0.23) were quantified and reported in percentages. The energy content was 508 ± 0.48 kcal. Acidic values, peroxide values and saponification values in walnut oil were 3 ± 0.14, 0.3 ± 0.06 and 130 ± 0.54 respectively. Furthermore, the average mineral contents were also determined. In general, it can be claimed that fresh walnuts have significant amounts of protein, oil and minerals, and higher water content in comparison with dry nuts. Nonetheless, our results in comparison with the information available about dry walnuts showed that fresh walnuts contained less oil content compared to dried fruits.

Keywords

• Antioxidant
• Fatty acids
• Juglans regia
• Peroxide value