Bioprocessing of pineapple waste for sustainable production of bioactive compounds using solid-state fermentation

The bioprocessing of pineapple wastes into value-added bioproducts is a sustainable solution. This study examined a novel alternative for producing bioactive compounds using Aspergillus niger GH1 for solid-state fermentation (SSF) of pineapple peel and core. The results revealed that the chemical composition of pineapple waste was suitable for use in SSF. During the first 32 h of the SSF, free phenols increased by 72.31% and were positively related to antioxidant activity as measured by DPPH (2,2-diphenyl-1-picrylhydrazyl). ß-Glucosidase and cellulase activities were increased by the SSF and were positively associated with free phenolic acids such as 5-caffeoylquinic acid. Scanning electron microscopy (SEM) confirmed mycelial invasion in pineapple waste. Analysis of free and bound phenols by high-performance liquid chromatography-mass spectrometry (HPLC-MS) showed more conjugated phenols in the unfermented than fermented waste. These results provided a broad overview of the chemical compounds with antioxidant capacity that are generated from the growth of A. niger.