Blanch Time and Cultivar Effects on Quality of Frozen and Stored Corn and Broccoli
Three corn and 2 broccoli cultivars were steam blanched for various times and evaluated for residual enzyme activity. Lipoxygenase was inactivated in 4 min in supersweet corn, while sweet corn required a 6-min blanch; peroxidase was inactivated in 8 min. Inactivation of broccoli lipoxygenase, peroxidase, and cystine lyase was achieved in 90 s. Blanched samples were stored 9 mo at -18 °C, then analyzed for color, texture, hexanal, free fatty acids, and sugars. Firmness increased significantly with blanching in both commodities, then declined. Short blanch treatments targeting lipoxygenase inactivation positively affected color and texture of both corn and broccoli. Changes in current industry practices are recommended.