## 4 Discussion
The stability of the red color is expressed through the a/b ratio, which is the ratio between the relative intensities of the red (lycopene) and yellow (carotene) pigments; the higher this ratio, the better the quality of the processed product [42]. The loamy soil presumably favored a better ratio between lycopene and carotenoid accumulation in the fruit. The higher dry matter and lower fruit firmness observed upon compost application, compared with mineral fertilization, are probably associated to a gradual and prolonged nutrient release. The compost and compost + mineral treatments supposedly enhanced the biosynthesis of lycopene and carotenoids, thereby contributing to an improved a/b ratio of the fruit color. A study conducted by [PERSON] et al. [7] demonstrated the effect of compost as well as organic and inorganic fertilizers on soil parameters, such as pH levels and microbial flora activity. The vital processes of the microbial flora play a significant role in facilitating the availability of numerous nutrients for plant growth. [PERSON] et al. [7] further affirmed that incorporating compost into the soil not only improved hydraulic conditions but also the exchange of cations and air within the soil (interstitial spaces between soil aggregates). In our study, we recorded a significant interaction between different types of fertilizers and soils on these variables: fruit dry matter, phenols, flavonoids, lycopene, antioxidant activity, and ascorbic acid in tomato fruit. [PERSON] [43] postulated that the accumulation of dry matter in tomato fruits may be associated with the water availability for plant synthesis of substances contributing to an increase in dry matter content. In our study, we found that the highest accumulation of dry matter was observed in the loamy soil with compost incorporation, presumably encouraged by better conditions for nutrient and water availability compared to the other treatments. The precursors of phenols in tomato include glucose, fructose, and other sugars present in the plant, which are converted into phenols through a series of enzymatic reactions during fruit ripening [44]. Specifically, the enzyme phenylalanine ammonia-lyase (PAL) catalyzes the conversion of the amino acid phenylalanine into cinnamic acid, which in turn serves as a precursor for the synthesis of many phenols in tomato. Subsequently, other enzymes such as cinnamate 4-hydroxylase (C4H) and 4-coumarate:coenzyme A ligase (4 CL) convert cinnamic acid into phenolic compounds such as p-coumaric acid, caffeic acid, and ferulic acid [44]. These phenolic compounds are responsible for the antioxidant properties and health benefits associated with tomato consumption. In our study, the accumulation of sugars, which subsequently led to phenol increase, was associated to a well-balanced condition of mineral elements (e.g., N, P, and K) in the following treatments: compost applied to loamy soil and mineral fertilizer applied to clayey and sandy soils. A study conducted by [PERSON] et al. [45] established a connection between the content and characterization of phenols in tomato fruit and thermal conditions. It is likely that in our study, the increased accumulation of phenols can be attributed to more favorable soil thermal conditions in the loamy + compost treatment compared to those of sandy + compost treatment. In our study, the compost treatment application to clayey and sandy soils probably facilitated the assimilation of potassium, which contributed to a quicker fruit-ripening process that subsequently led to an increase in lycopene [46] content compared to that of fruits not fully ripe, except in the case of the mineral and soil treatment. In our study, the compost treatment application to clayey and sandy soils probably made the assimilation of potassium easier, which contributed to a quicker fruit-ripening process, subsequently resulting in an increase in lycopene [46] content compared to that of fruits not fully ripe, except in the case of the mineral and soil treatment.