Sugar Snap Pea Quality Changes in Relation to Storage Temperatures and Atmospheres

Sugar snap peas are increasing in importance as components of vegetable trays.  Sugar snap peas (cv Sugar Daddy and Sugar Snap) were stored at 5C in air or air or a range of controlled atmospheres (3%O2 alone or with 6, 12 or 18%CO2, and 1 or 10%O2 with 12%CO2). After 12 days storage, peas in air and all atmospheres were of marketable quality.  By 15 days, both cultivars were injured by the 3%O2+18%CO2 and 1%O2+12%CO2 atmospheres. The best storage atmospheres for 18 days were normal air, 3%O2, 3%O2+6%CO2, and 10%O2+12%CO2.  Sugar and Vitamin C concentrations declined with time under all storage conditions, but were not notably affected by the atmospheres.  Very high concentrations of acetaldehyde and ethanol were found in peas stored in 1%O2+12%CO2, with significant increases after 6 days of storage.  Increases in fermentative volatiles were also observed in the 3%O2 +12% or 18%CO2 atmospheres.  The same 3 atmospheres also resulted in increased electrolyte leakage and ammonia concentrations.  In another experiment the same two cultivars were stored at 0C in air and at 5C in air or CA (3%O2, 3%O2 + 6%CO2, 3%O2 + 12%CO2, or 10%O2 +12%CO2) for up to 24 days.  Visual quality evaluations indicated that all peas were marketable after 24 days under all conditions.  Sugar and Vitamin C concentrations declined under all storage conditions, but concentrations were not affected by the atmospheres used.  Other indicators of stress (acetaldehyde and ethanol, ammonia, and electrolyte leakage) also showed that the peas tolerated all storage conditions.  Respiration rates were similar among 3 cultivars and averaged 11.5, 16.5, and 32 µL CO2/mg-h at 0, 5 and 10C, respectively.  The most beneficial condition for sugar snap peas is storage in air at or near 0C.  At 5C, some of the atmospheres tested offer modest benefit over air storage at that temperature.