Solid-State Fermentation as a Sustainable Tool for Extracting Phenolic Compounds from Cascalote Pods

Abstract

Cascalote pods are an important source of phenolic compounds, mainly recovered using solvent extraction methods. To find a sustainable alternative to these methods, this study aimed to evaluate solid-state fermentation (SSF) in order to enhance the extractability of total phenolic compounds (TPC) with antioxidant activity (AA) from cascalote pods. Aspergillus niger GH1 was selected based on the amount of TPC released and AA measured (ABTS, DPPH, FRAP) in a short period of time. Moreover, moisture, temperature, inoculum size, and mineral composition were evaluated. The largest amount of TPC released was 124.17 mg/gdw (g of dry weight) after 12 h of culture, which significantly correlated with the AA (Pearson’s R = 0.94). Moisture and KH2PO4 concentration were the main influencing factors of TPC release. Treatment 6 (1 × 107 spores/gdw, 30 °C, 60% moisture, mineral composition (g/L): KH2PO4, 1.52; NaNO3, 7.65; and MgSO4, 1.52) was selected due to the highest values of both TPC and AA. SSF-assisted extraction allowed for an increase of 118% and 93% in TPC and AA values, respectively. Corilagin, lagerstannin, geraniin, and ellagic acid were the main phenolic compounds identified by RP-HPLC-ESI-MS in the cascalote extracts. The results obtained demonstrate the feasibility of SSF-assisted extraction as a biotechnological alternative for the recovery of important bioactive molecules from this underutilized material.

Application of Fermentation as a Strategy for the Transformation and Valorization of Vegetable Matrices

“…On the other hand, drying is important to stabilize the raw material and concentrate the nutrients [92]. Other parameters such as temperature, time, amount of inoculum, humidity, and pH notably affect the performance of the solid-state fermentation process [93,94].…”

“…SSF is also successfully applied to produce other metabolites of interest, such as aromatic compounds, dyes, or preservatives. Among the aromatic compounds, 2-phenylethane and 2-phenethyl acetate stand out, which are involved in the bioconversion of L-phenylalanine into aromatic compounds with a rose odor [93]; aldehyde alcohols and ketones, with an intense fruity aroma [95]; and the unsaturated δ-lactone 6 pentyl-α-pyrone appreciated for its coconut aroma [96]. On the other hand, there are preservatives such as astaxanthin, a red/yellow carotenoid pigment used as a preservative in the encapsulation of oils due to its high antioxidant activity [97]; citric acid, which, in addition to being used as a flavor enhancer, prevents oxidation reactions [98]; and lactic acid.…”

Kinetic Study of Fig Syrup Fermentation by Genetically Modified Saccharomyces cerevisiae Yeast Strains: A Physicochemical Approach to the Yeast Strain Life Cycle

“…The selection of figs as a carbon source for biocatalysts is justified by their costeffectiveness, widespread utilization in the food industry and the enriched sugar composition [28,29]. The utilization of dried figs, readily available in commercial markets, offers the advantage of the prolonged preservation of their intrinsic properties [30].…”