*3.4. Effects of Low Oxygen Conditions on Colour Development of Mature Green Tomatoes Cultivated with and without Far Red Lighting*

During cold storage red colour development was blocked, as indicated by the constant NAI values, irrespective of low oxygen treatments for both MG fruit cultivated with and without FR lighting. Colour development for the temperature control tomatoes started immediately, although faster for the MG tomatoes cultivated with FR lighting (Figure 7). During shelf-life, colour development was similar for the different low temperature oxygen storage treatments in fruit without FR lighting. Fruit cultivated with FR lighting reached higher NAI values in fruit prior stored at the low oxygen concentrations (*p <* 0.001) (Figure 7B). NDVI values were not significantly affected by oxygen level nor FR treatment.

**Figure 7.** Colour indicated by NDVI (dotted lines) or NAI (full lines) values of MG tomatoes cultivated under white LED light (WL) without far red lighting (**A**) or with far red lighting during cultivation (**B**) during cold storage (blue area) at 2 or 12 ◦C and subsequent shelf-life at 20 ◦C (white area). Orange, green, red and purple lines and symbols indicate 1, 5 and 21 kPa O2 (low oxygen control) applied during storage at 2 ◦C, and 21 kPa O2 at 12 ◦C (temperature control), respectively. The average NDVI and NAI values with indicated standard error are shown for two replicates of four tomatoes (*n* = 2). LSD values (*p* < 0.05) are indicated per panel.
