Quantification of Vitamins, Minerals, and Amino Acids in Black Walnut (Juglans nigra)

Salma Akter Antora; Khanh-Van Ho; Chung-Ho Lin; Andrew L Thomas; Sarah T Lovell; Kiruba Krishnaswamy

doi:10.3389/fnut.2022.936189

Quantification of Vitamins, Minerals, and Amino Acids in Black Walnut (Juglans nigra)

Front Nutr. 2022 Jul 27:9:936189. doi: 10.3389/fnut.2022.936189. eCollection 2022.

Authors

Salma Akter Antora¹, Khanh-Van Ho^{2

3

4

5}, Chung-Ho Lin^{2

6}, Andrew L Thomas⁷, Sarah T Lovell^{2

6}, Kiruba Krishnaswamy^{1

8}

Affiliations

¹ Department of Biomedical, Biological and Chemical Engineering, University of Missouri, Columbia, MO, United States.
² Center for Agroforestry, School of Natural Resources, University of Missouri, Columbia, MO, United States.
³ Department of Chemistry, University of Missouri, Columbia, MO, United States.
⁴ Molecular Imaging and Theranostics Center, University of Missouri, Columbia, MO, United States.
⁵ Department of Food Technology, Can Tho University, Can Tho, Vietnam.
⁶ School of Natural Resources, University of Missouri, Columbia, MO, United States.
⁷ Division of Plant Sciences, Southwest Research Center, University of Missouri, Columbia, MO, United States.
⁸ Division of Food, Nutrition and Exercise Sciences, University of Missouri, Columbia, MO, United States.

Abstract

This paper aims to quantify the micronutrients in black walnut and address its human health benefits. The metabolic profiling of 11 black walnut cultivars was accomplished using ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight high-resolution mass spectrometer. Results revealed that the highest concentration of vitamin B₉ was present in cultivar "Daniel" (avg. relative signal intensity 229.53 × 10⁴ mAU). "Surprise" and "Daniel" cultivars had the highest amount of vitamin B₅. However, vitamin A, D₃, E, and K showed no significant difference among the cultivars. The vitamin content levels among the cultivars were compared by applying one way ANOVA method with (P < 0.05) significance level. Mineral analysis for the black walnut kernel, Persian walnut, and black walnut protein powder was done using Inductively Coupled Plasma Optical Emission spectroscopy. The experimental data for black walnut kernel is 0.04 mg/g for Fe and 0.03 mg/g for Zn, and for black walnut, protein powder is 0.07 mg/g for Fe and 0.07 mg/g for Zn. The amino acid analysis and comparison with black walnut kernel show that black walnut flour and protein powder have a higher amount of essential and non-essential amino acids. Therefore, researchers, food process engineers, and food product developers should consider the health benefits of black walnuts and explore the commercial potential of this native agroforestry crop.

Keywords: agroforestry; cultivars; food and health; indigenous; metabolomics (OMICS); micronutrients; plant based food.