Walnut (Juglans regia L.) kernel postharvest deterioration as affected by pellicle integrity, cultivar and oxygen concentration

•The role of pellicle and low-oxygen storage on kernel consumer quality was studied.•Shelling caused pellicle disruption and accelerated kernel browning.•Walnut oil degradation was favored by pellicle damage occurring during shelling.•Impact of shelling damage was related to genotype.•‘Howard’ kernel color benefitted from oxygen equal to or lower than 3 kPa. Increased demand for convenient, healthy foods has promoted the commercialization of shelled, more perishable walnut kernels. In this work for two of the major commercial walnut cultivars (‘Chandler’ and ‘Howard’) we determined the influence that disruption of the integrity of the seed coat pellicle during shelling operations trigger postharvest deterioration. Commercially mature ‘Chandler’ and ‘Howard’ nuts were subjected to Gentle (GS,