Comprehensive Characterization of Free Amino Acids in 18 Pecan Varieties Over 2 Harvest Years

High Resolution Image Download MS PowerPoint Slide Free amino acids (FAAs) play an important role in nutritional quality and may contribute to taste in pecan ( Carya illinoinensis ) kernels, yet their profiles remain largely unreported. This study quantified 21 FAAs in 26 pecan samples representing 18 varieties collected over 2 harvest years using GC−MS with supplemental HPLC-UV analysis. Total FAAs ranged from 57.9 to 123.8 mg/100 g whole kernel in the 2019 batch and from 70.1 to 167.4 mg/100 g in 2020, including all nine essential, nine non-essential, and three uncommon amino acids. Glutamic and aspartic acid were (potential contributors to umami taste) consistently the most abundant and accounted for most umami-related amino acids (12.07−39.84 and 6.85−26.05 mg/100 g, respectively). Significant variety and harvest-year effects were observed for most amino acids, and PCA revealed distinct patterns among specific varieties, with variety contributing the greatest proportion of variation. These findings provide the first multivariety, multiyear characterization of FAA composition in pecan kernels and offer insights relevant to pecan quality evaluation and breeding.