*3.1. Chilling Injury, Relative Conductivity, and Mass Loss in Sweet Potato Tuberous Roots*

The typical symptoms of CI in sweet potato tuberous roots are pitting, water-soaked areas, and skin depression. Moreover, fungal infestation may be observed in damaged tissues in severe cases. The tuberous root in the CS group had no CI symptoms after 14 d at 5 ◦C plus 3 d of shelf display, whereas slight surface pitting and internal browning developed after 21 d at 5 ◦C and 3 d at 20 ◦C. Tuberous roots stored at 13 ◦C did not develop CI even after 21 d of storage (Figure 1A,B).

**Figure 1.** The color changes, relative conductivity, and mass loss of sweet potato tuberous roots during 21 d storage at the control and CS group. (**A**) color changes on the cutting surface, (**B**) color changes on the skin, (**C**) relative conductivity, (**D**) relative mass-loss rates. Results are expressed as the mean ± standard error of three replicates. Different characters indicate significant differences between treatment means at the *p* < 0.05 level.

As shown in Figure 1C, the relative conductivity of either control or CS tuberous roots increased throughout storage. No significant difference was detected between the control or CS group until day 21, where the relative conductivity was 8.5% higher than that of the control group.

Excessive mass loss can compromise the quality of fresh produce. As shown in Figure 1D, the two groups underwent substantial loss after 21 d of storage, reaching up to 11.8% and 9.3% at 13 and 5 ◦C, respectively. The mass loss at 13 ◦C was significantly higher (*p* < 0.05) than that at 5 ◦C.
