*2.5. Cracking Index (CI) and Maturity Evaluation Parameters*

The cv. Lapins presented higher values for all the analyzed routine parameters (Figure 5A–D). According to [29], total soluble solids (TSS) depend on cultivar, mainly due to glucose and fructose and less to the presence of sucrose and sorbitol, being related to flavor intensity. In this work, cv. Lapins presented a TSS value twice higher than that of cv. Early Bigi (averages of 19.37 and 9.80 ◦Brix, respectively), indicating a significantly higher sugar content in cv. Lapins (*p* = 0.000). Maturity index (MI), as the ratio between TSS and TA (titratable acidity), is also an indicator of sweetness and consequently of maturity [30,31], allowing us to conclude that cv. Lapins (MI = 2.77) was significantly more mature at harvesting time than cv. Early Bigi (MI = 1.73) (*p* = 0.000). As cv. Early Bigi is one of the earliest cultivars collected in the Resende region, it can be sold at a good price and it is therefore a very profitable cultivar in the region.

**Figure 5.** Correlations between (**A**) the cracking index (%) and the total soluble solids (◦Brix), (**B**) the cracking index (%) and the titratable acidity (g citric acid 100 g−<sup>1</sup> ), (**C**) the cracking index (%) and the maturity index (TSS/TA), and (**D**) the cracking index (%) and the pH of two sweet cherry cultivars: Early Bigi and Lapins.

Positive correlations were observed between the CI and all the analyzed routine parameters, with the exception of pH (Figure 5A–D). This means that the higher the total soluble solids, the titratable acidity and the maturity index, the greater the CI. Stronger correlations were found between the CI and TSS (R<sup>2</sup> = 0.9633, *p* = 0.001) and the CI and the MI (R<sup>2</sup> = 0.9544, *p* = 0.001). These results were consistent with the findings of [32], who also reported a positive correlation between the TSS and fruit cracking in sweet cherry cultivars. [33] also demonstrated that the susceptibility to cracking increased with the maturation stage.
