Effect of Moisture Content of Fresh Pecans on Mechanical Shelling Efficiency, Nutritional Features, and Packaging Method

Fresh pecans are increasingly popular for their sweet taste and high nutritional value. To facilitate their commercialization, it is crucial to screen the proper moisture content for efficient mechanical shelling while retaining nutritional quality and finding a reasonable packaging method for storage. This study compared the mechanical shelling efficiencies of fresh pecans with different moisture contents via a standardized evaluation system used by the U.S. Department of Agriculture for over 70 years. The results indicated that pecans dried for 24 h (17.51% moisture, wet basis) achieved the highest mechanical shelling efficiency with the lowest kernel shoulders damaged (DSh%, 31.7%), shortest separation time (10.67 min·kg^-1), and highest rate of complete halves (CH, 91.6%). Compared with dried pecans, fresh pecans had a lighter testa color (<i>L*</i>, 55.05), higher 2,2-Diphenyl-1-picrylhydrazyl (DPPH, 18.88 μg TE·g^-1) and 2,2'-Azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS, 87.15 μmol TE·g^-1), free-radical scavenging activity, and lower acid values (AV, 0.21 mg·g^-1) and peroxide values (PV, 0.003 mg·g^-1). Aluminum film packaging with vacuum (ALV) best preserved the quality of fresh pecans during 9 months of storage, as indicated by the acid and peroxide values. The results of this study provided a first report for the industrialization of fresh pecans.