## 3 Results and Discussion  
### Physicochemical Quality  
Visual observation  
Comparing fresh-untreated purple carrots on day 0 (Figure 2a) with fresh-untreated ones stored for 21 days (Figure 2b), whitening was apparent as a result of the natural evolution of the samples over storage. The reason for the color change was the formation of lignin as a healing process of wounded tissues [27]. In addition, visible softness and moisture loss were also apparent in untreated roots as compared with fresh carrots on day 0. However, treated samples, whatever the phytoregulatory used, maintained very similar color and apparent firmness to that of fresh-untreated samples on day 0 (Figure 2c,d). A comparison between MJ- and ABA-treated carrots reflected brighter color and visually higher water content for the carrots exposed to ABA. Physicochemical parameters  
Figure 3 depicts the moisture content and juiciness of purple carrot samples. As observed, both parameters maintained reasonable steadiness in most samples. Specifically, moisture content always ranged between 86.3 and 88.4% and juiciness between 30 and 35%. No significant (\(p>0.05\)) influence of storage or of elicitation was found. An exception was found in MJ-treated samples, which displayed significantly (\(p<0.05\)) lower moisture content (i.e., 83.8%) and, in particular, juiciness (i.e., 15%). Figure 4 represents TSS (% \(\circ\)'Brix) (a) and acidity, expressed as TTA (%) and pH (b). As seen, TSS increased significantly (\(p<0.05\)) in fresh-untreated purple carrots from day 0 (i.e., \(\circ\)'Brix 5.0%) to day 21 (i.e., \(\circ\)'Brix 5.65%). This reflects an increase in sugar content in carrot roots during the 21-day cold storage. The enhancement of sugars during ripening and storage has already been described in tubers [28; 29] and other vegetables [30]. It is attributed to hydrolysis of polysaccharides into oligosaccharides and monosaccharides. It can also be due to the degradation of pectin substances into simple sugars occurring over ripening [31]. The increase in TSS with storage diminished significantly (\(p<0.05\)) with elicitation, regardless of the phytoregulatory used (i.e., 5.25% for MJ and 5.45% for  
Figure 2: Purple carrot (_Purple Haze_ variety): fresh on the reception day (a), untreated after storage (b), MJ-treated after storage (c), ABA-treated after storage (d). ABA). As seen in the figure, no significant (\(p>0.05\)) differences were found between both phytoregulators. Since TSS increment is related to ripening, the reduction in the TSS increment with elicitation indicates that treatment with MJ or ABA is effective in delaying spoilage and, hence, extending purple carrot shelf-life. From Figure 4b, TTA, measured as % malic acid, increased significantly (\(p<0.05\)) in fresh-untreated purple carrots with storage (i.e., from 0.08% on day 0 to 0.12% on day 21). The increase of TTA with storage here observed supports findings earlier published by other researchers [28; 29]. It is most like due to the formation of acids by oxidation of reducing sugars or by breakdown of pectin substance, which can be in turn converted into organic acids or simple sugars, as previously commented. Regarding treatment effect, the trend found for both phytoregulators was similar. They both reduced TTA increase during the post-harvest period (i.e., 0.10% for MJ-treated carrots and 0.07% for ABA-treated carrots), although it is interesting to point out that only ABA impact was statistically significant (\(p<0.05\)). In fact, ABA-treated carrots provided TTA values similar to those measured in fresh-untreated carrots on day 0 (i.e., 0.07% and 0.08%, respectively). The slowdown of TTA increase over storage as a consequence of elicitation supports the hypothesis above mentioned about the delaying effect of MJ and ABA on the decay rate.