*3.1. Experiment 1: Effects of Low Oxygen Conditions on CI Indices, Weight- and Firmness Loss*

In the first experiment, typical CI symptoms such as pitting, uneven colouring and decay were observed for both MG and R tomatoes during low oxygen storage and shelflife. Storage at 0.5 kPa oxygen resulted in necrosis, fungal infection and rotting and were therefore omitted from this study. In MG tomatoes there were generally no visible CI symptoms observed during cold storage, except for tomatoes stored at 5 kPa O2 (Figure 1A). During the shelf-life, fruit (MG and R), prior stored at 2.5 kPa O2, showed the lowest, and RA the highest disorder (Figure 1). MG tomatoes from the temperature control (12 ◦C) also developed some pitting, comparable to the tomatoes stored at 2.5 kPa O2. R tomatoes stored at 12 ◦C (temperature control) developed the least decay. At 2 ◦C, the R tomatoes stored at 2.5 kPa showed the least decay while the fruit stored at RA developed the highest disorder after 20 days of shelf-life which prevented further measurements. On the other hand, R tomatoes from the temperature control (21 kPa at 12 ◦C) developed the lowest decay (*p <* 0.0001). This indicated that the storage at 12 ◦C also resulted in a small amount of CI symptoms. In general, MG tomatoes developed slower pitting than R tomatoes, indicating that R tomatoes were surprisingly more sensitive to cold storage than MG tomatoes.

**Figure 1.** Chilling injury symptoms as indicated by the disorder index of MG (**A**) and R (**B**) tomatoes during cold storage at 2 or 12 ◦C (blue area) and subsequent shelf-life at 20 ◦C (white area). Blue, green, red and purple lines and symbols indicate 2.5, 5, 21 kPa O2 (low oxygen control) applied during storage at 2 ◦C and 21 kPa O2 at 12 ◦C (temperature control), respectively. The average decay index with indicated standard error is shown for five tomatoes. LSD values (*p* < 0.05) are indicated per panel. Disorder in MG fruit was determined by averaging the values of the pitting and uneven ripening index; disorder in R fruit was determined by the average decay incidence.

Weight loss was higher for MG compared to R tomatoes (Figure 2). Fruit stored at 12 ◦C showed highest weight loss. The lowest weight loss for both MG and R tomatoes was observed in fruit that had been stored at 2 ◦C and 2.5 kPa O2 (*p <* 0.005). Fruit stored at 12 ◦C and stored at 2.5 or 5 kPa O2 at 2 ◦C showed less softening compared to fruit stored at 2 ◦C and 21 kPa O2 (Figure 3).

**Figure 2.** Weight loss of MG (**A**) and R (**B**) tomatoes during cold storage at 2 or 12 ◦C (blue area) and subsequent shelf-life at 20 ◦C (white area). Blue, green, red and purple lines and symbols indicate 2.5, 5, 21 kPa O2 (low oxygen control) applied during storage at 2 ◦C and 21 kPa O2 at 12 ◦C (temperature control), respectively. The average weight loss with indicated standard error is shown for five tomatoes. LSD values (*p* < 0.05) are indicated per panel.

**Figure 3.** Firmness index of MG (**A**) and R (**B**) tomatoes during cold storage at 2 or 12 ◦C (blue area) and subsequent shelf-life at 20 ◦C (white area). Blue, green, red and purple lines and symbols indicate 2.5, 5, 21 kPa O2 (low oxygen control) applied during storage at 2 ◦C and 21 kPa O2 at 12 ◦C (temperature control), respectively. The average firmness index with indicated standard error is shown for five tomatoes. LSD values (*p* < 0.05) are indicated per panel.

### *3.2. Experiment 1: Effects of Low Oxygen Conditions on Tomato Colour Development*

Red colour formation for MG fruit, as indicated by NAI values, was limited for all fruit that had been stored at 2 ◦C, independent of the oxygen level. Fruit stored at 12 ◦C showed colouration during subsequent shelf life at 20 ◦C. (Figure 4A). During low oxygen storage, more chlorophyll breakdown was observed with increasing oxygen levels. In R tomatoes, all treatments, except for the tomatoes in the temperature control, showed a reduction in the NAI values during cold storage. During shelf-life, fruit from all treatments showed increasing NAI values, except for the RA control (Figure 4B).

**Figure 4.** Colour as indicated by NDVI (dotted lines) and NAI (full lines) index of MG (**A**) and R (**B**) tomatoes during cold storage at 2 or 12 ◦C (blue area) and subsequent shelf-life at 20 ◦C (white area). Blue, green, red and purple lines and symbols indicate 2.5, 5, 21 kPa O2 (low oxygen control) applied during storage at 2 ◦C and 21 kPa O2 at 12 ◦C (temperature control), respectively. The NDVI or NAI with indicated standard error is shown for five individual tomatoes (repeated measure over times). LSD values (*p* < 0.05) are indicated per panel.
