# Comprehensive Assessment of the Dynamics of Banana Chilling Injury by Advanced Optical Techniques
## 3 Results
### Results of Spectral Measurements  
Remission spectra of all samples pronouncedly differed from that of untreated banana mainly in shelf life but only slightly during storage (Figure 5). Here, changes tended to be the more distinct the higher the temperature during storage, especially at 10 \({}^{\circ}\)C and 11.5 \({}^{\circ}\)C. Most obviously, remission from fruit increased in the chlorophyll spectral absorption region between 600 and 750 nm, indicating that the concentration of these compounds substantially declined. Nevertheless, during shelf life, shoulders were clearly visible in the range of 585 nm and at approx. 530 nm, at least in spectra of samples stored at 11.5 \({}^{\circ}\)C and 13 \({}^{\circ}\)C. On the other hand, no marked variation of the remission signals was recorded in the above wavelength ranges. Figure 3: Means (\(\pm\)SD, \(n=6\)) of the performance index (\(PI_{\text{ABS}}\)) and the maximum primary yield of PSII (\(F_{\text{v}}/F_{\text{o}}\)) of banana fruit obtained from the polyphasic rise of the rapid chlorophyll-fluorescence induction curve measured with the OJIP test (FluorPen) during cold storage (\(\circ\) circles: 5 \({}^{\circ}\)C; \(\square\) squares: 10 \({}^{\circ}\)C; \(\Delta\) triangles: 11.5 \({}^{\circ}\)C; \(\Diamond\) diamonds: 13 \({}^{\circ}\)C) and shelf life. The vertical dashed line indicates the end of cold storage on day 12 of the experiment. The filled circles reflect the means (the grey horizontal bar shows the respective SD) of all bananas (\(n=76\)), measured before storage. Different small letters indicate significant (\(p<0.05\)) differences between means. Figure 4: Means (\(\pm\)SD, \(n=6\)) of the maximum photosynthetic quantum yield (\(\alpha\)), the maximum light saturated electron transport rate (\(ETR_{\text{max}}\)), the photochemical quenching coefficient (\(q_{\text{P}}\)), the non-photochemical quenching (\(NPQ\)), and the quantum yields of regulated (\(\gamma_{\text{NPQ}}\)) and non-regulated non-photochemical energy loss in PSII (\(Y_{\text{NO}}\)) of banana fruit measured by rapid light curves (\({}^{\text{max}}PFR=235\)\(\mu\)mol m\({}^{-2}\) s\({}^{-1}\)) with PAM fluorometers during cold storage (\(\Circle\) circles: 5 \(\Circle\); \(\square\) squares: 10 \(\Circle\); \(\triangle\) triangles: 11.5 \(\Circle\);\(\Diamond\) diamonds: 13 \(\Circle\)) and shelf life. The vertical dashed line indicates the end of cold storage on day 12 of the experiment. The filled circles reflect the means (the grey horizontal bar shows the respective SD) of all bananas (\(n=76\)), measured before storage. Different small letters indicate significant (\(p<0.05\)) differences between means. Figure 5: Differences of averaged remittance spectra (tec5 spectrometer) of the banana stored at the different temperatures (**A**: 5 \(\Circle\); **B**: 10 \(\Circle\); **C**: 11.5 \(\Circle\); **D**: 13 \(\Circle\); measured on days 2, 6, 12) and in shelf life (days 19, 23), and those of the untreated fruit on day 0. As could be deduced from the changes in remission spectra differences, the NDVI did not vary during cold storage, irrespective of the storage temperature (Figure 6). However, it rapidly declined close to zero in simulated shelf life in banana previously stored at or above 10 \({}^{\circ}\)C but to a significantly smaller extent in those kept at 5 \({}^{\circ}\)C. Similarly, \(L^{*}\)\(a^{*}\)\(b^{*}\) color characteristics did not (\(L^{*}\), \(b^{*}\)) or only marginally (\(a^{*}\)) change during cold storage (Figure S1). During simulated shelf life, these parameters varied much more pronouncedly, especially after storage at moderate temperatures.