Mechanism of Chilling Injury in Sweet Potatoes

1. 1. Both amounts of lipid phosphorus and acid-insoluble nitrogen in the mitochondrial fraction from chilling-injured sweet potatoes (var. Okinawa 100) were larger than in the fraction from healthy sweet potatoes. The N-amount appeared to be increased more by chilling-injury than the P-amount.

2. 2. Sweet potato, a tropical plant, showed lower value of the degree of unsaturation of fatty acids in mitochondrial fraction than white potato, a temperate-zone plant.

3. 3. The amount of unsaturated fatty acids of C₁₆, C₁₈ and C₂₀ as percentage of the total fatty acids was higher in mitochondrial fractions from chilling-injured sweet potatoes (var. Okinawa 100 and var. Norin 1) than in mitochondrial fractions from healthy sweet potatoes. However, in the case of white potato mitochondrial fraction no detectable difference was observed between storage at 0~1°C and at 10~14°C.