BIOMOLECULES CORRELATION IN JACKFRUIT WASTES BEFORE AND AFTER SOLID-STATE FERMENTATION (SSF)

Biomolecules represent essential components of cells and can undergo secretion or consumption during Solid State Fermentation (SSF) – a biotechnological process that mimics the natural environment of fungi, enabling the valorization of plant wastes. The present study evaluated the correlation of biomolecules (proteins, phenolics, reducing sugars, antioxidant, protease, and lipase activity) in jackfruit residues before and after SSF. The jackfruit wastes (peel, seed, and core) were utilized as substrates in two distinct masses (10 g and 20 g) within a bioreactor and were inoculated with Aspergillus niger CBMAI 2084, with parameters of inoculum concentration (10⁷ spores/mL), duration (120 hours), and temperature (30 °C) maintained. The quantification of total soluble proteins, total phenolics, reducing sugars, antioxidant activity through DPPH radical scavenging, and enzymatic activities (protease and lipase) was conducted for both fermented and non-fermented wastes. Subsequently, all data were analyzed using Spearman's correlation (Sc) or Pearson's correlation (Pc), based on data normality, considering only those with statistical significance in the t-test (p < 0.05) for discussion. The initial observation refers to the Sc between total soluble proteins and lipase activity (⍴ = 0.70), where a concomitant increase in both is observed, suggesting that the protein composition is predominantly constituted by lipases. The obtained Sc value (⍴ = 0.70) between total phenolics and antioxidant activity indicates an increase in antioxidant activity with an increase in phenolic content. This association is already recognized for this class of biomolecules, given the ability of certain polyphenols to prevent oxidative stress, suggesting that jackfruit contains phenolic compounds with antioxidant properties. Furthermore, the Sc analysis revealed a negative association between reducing sugars and antioxidant activity (⍴ = -0.82). This suggests that a decrease in sugar levels occurs when an increase in antioxidant activity is observed, which may be due to the fungus using reducing sugars as an energy source during fermentation, possibly converting this consumption into antioxidant biomolecules. Subsequently, Pc analysis was employed to examine the relationship between proteolytic activity and antioxidant activity (r = 0.798), indicating that an increase in proteases during fermentation could also probably release antioxidant peptides present in the wastes and/or generated during SSF. The results obtained demonstrated a strong correlation and highlighted the increase in antioxidant activity, in addition to the ability of SSF to influence the quantities of biomolecules in jackfruit residues, contributing to the valorization of these residues and to the understanding of the biochemical mechanisms involved.