## 4 Discussion
### Effect of VI on Chlorophyll Content of Spinach Leaves  
Chlorophyll degradation can cause loss of green color or yellowing in spinach leaves and subsequently decreasing the market value of spinach [35]. Our findings showed that GABA, sucrose and SA impregnated leaves were able to reduce chlorophyll degradation as much as 57%, 55% and 49%, respectively, as compared to the non-impregnated leaves which lost to 80% chlorophyll on 7 th day of storage (Figure 1b). Similar findings were also reported by [PERSON] et al. [36], [PERSON] et al. [37] and [PERSON] et al. [22] on the effect of GABA, SA and sucrose, respectively, in chlorophyll degradation. [PERSON] et al. [37] explained that plants suffering from chilling stress can cause membrane damage, ROS generation and toxic compound accumulation, which can lead to a reduction of chlorophyll content, the disintegration of chloroplast membranes, disruption of photosystem biochemical reactions and the reduction of photosynthetic activity. Meanwhile, [PERSON] et al. [22] mentioned that delaying chlorophyll degradation in post-harvest treatment with sucrose might be related to the inhibition of enzyme activities and expression of genes associated with chlorophyll degradation. Our results from chroma meter show that L\({}^{\star}\) values (Figure 3a) for non-impregnated, GABA and sucrose impregnated leaves were increasing throughout 7 days of storage time. The exemption was made to SA impregnated leaves that shows a decreasing pattern on L\({}^{\star}\) values. Meanwhile, for the \(-\)a\({}^{\star}\) values (Figure 3b) which indicate the green color, recorded a decreasing trend for non-impregnated and all three impregnated leaves. These values were in line with the chlorophyll content that also decreasing throughout storage. However, a significant decrease was observed in non-impregnated leaves and SA impregnated leaves throughout the storage days. For b\({}^{\star}\) values (Figure 3c) which signify yellow color, non-impregnated and SA impregnated leaves showed higher value than GABA and sucrose impregnated leaves at the end of storage time. These values explained that yellowing of spinach leaves can be delayed by GABA and sucrose treatments as they can also reduce chlorophyll degradation by 49% and 55%, respectively, as compared to 80% reduction in non-impregnated leaves at the end of storage days. Effect of VI on Physicochemical Changes of Spinach Leaves: Weight Loss, Total Soluble Solids, Titatable Acidity and pH  
Physicochemical changes of the non-impregnated and impregnated spinach leaves were observed as they could be the indicator or symptoms of chilling injury. Weight loss in fruits and vegetables is mainly due to the loss of water caused by transpiration and respiration processes [38]. Based on our results, GABA impregnated leaves recorded the lowest percentage of weight loss after 7 days of storage time with 3%, followed by sucrose (4.2%) and SA (8%) impregnated leaves while higher weight loss was observed in non-impregnated (8.4%) leaves (Figure 1c). Higher loss of water in SA impregnated leaves can be explained by the low solubility of SA in water as compared to GABA and sucrose. According to [PERSON] and [PERSON] [39], the hydroxyl group in SA is hydrogen bonded intramolecularly to the carbonyl oxygen and, thus, reduced intermolecular hydrogen bonding which explains its low solubility in water. Therefore, more non-bonded water is available in SA impregnated leaves as compared to GABA and sucrose impregnated leaves which leads to a higher loss of unbound water. According to [PERSON] et al. [40], total soluble solids reflects the sugar content in spinach leaves. Our results show that sucrose impregnated leaves have significantly highest total soluble solid followed by non-impregnated leaves, GABA and SA impregnated leaves (Figure 2a). The high soluble solid content in sucrose impregnated leaves (8 \({}^{\circ}\)Brix \(\pm\) 1.2) was due to the exogenous sucrose feeding which result in higher sucrose content in the spinach leaves [33].