Effects of Temperature and Low Oxygen Atmospheres on Respiration, Chip Color, Sugars, and Malate of Stored Potatoes1

Abstract

Abstract Following curing and a period of storage at 10°C, potato (Solanum tuberosum L.) tubers were stored for 4 to 5 weeks at 1° or 10° in controlled atmospheres consisting of either air, 2.5% O2 (balance N2), or N2. CO2 production of tubers stored in air at 10° was relatively constant. When tubers were stored in air at 1°, CO2 production initially was lower than at 10° in air. It then increased to a maximum after about 15 days and eventually declined again. Storage in 2.5% O2 or N2 prevented the increase in CO2 production that occurred after several days of storage in air at 1°. Malate and citrate were the only organic acids detected in significant amounts in juice extracted from tubers when experiments were terminated. Changes in citrate showed no consistent trends. Tubers stored in air at 1° had higher sucrose, fructose, glucose, and malate levels than tubers stored at 10°. Storage in N2 at 1° prevented the malate, sucrose, and reducing sugar increases. Storage in 2.5% O2 inhibited the malate, fructose, and glucose increases at 1° and reduced the sucrose content of ‘Monona’ and ‘Norchip’ cultivars, which accumulated large amounts of sucrose during storage in air at 1°. Sucrose content of ‘Kennebec’ was not affected by 2.5% O2. Storage in 2.5% O2 slowed the accumulation of fructose and glucose, but only ‘Monona’ and ‘Norchip’ yielded acceptable chips after storage in 2.5% O2 at 1°. All 3 cultivars yielded acceptably colored chips after storage in N2 at 1°, but the development of blackheart when tubers were returned to air makes N2 an unacceptable storage atmosphere at this temperature. Storage in N2 resulted in soft rot at 10°.