Extraction, amino acid estimation, and characterization of bioactive constituents from peanut shell through eco-innovative techniques for food application

Agro-industrial waste has proved a huge problem owing to its disposal and impact on the environment. The eco-innovative technologies are applied to utilize waste as a resource. The mandate of the current investigation was to extract and characterize the bioactive molecules with special reference to luteolin from peanut shells through different innovative extraction techniques. This study was divided into two modules, in first the extraction of polyphenols was done through conventional and ultrasonic-assisted extraction (USE) by utilizing different solvents (ethanol 80%, methanol 80%, and water) and time intervals (5, 10 and 15 min for ultrasound and 30,60 & 90 min for conventional extraction technique) alongside HPLC and amino-acid characterization of a peanut shell. The results indicated that ultrasound proved significantly (p < .05) more effective as compared to conventional extraction and among solvent ethanol performed better as compared to methanol and water. Likewise, the time at 10 min also exhibited a significant effect on Peanut shell polyphenyl yield. The resultant highest value for TPC, DPPH, ABTS, FRAP, and β-carotene in ethanol of USE at 10 min was 3.79 ± 0.1 g GAE/100 g PS, 5.05 ± 0.1, 2.13 ± 0.03, 2.97 ± 0.03 and 5.33 ± 0.04 g TE/100 g PS, respectively. The resultant moieties exhibited high Luteolin contents after HPLC characterization and ranged from 1187 mg/g in conventional and 1409 mg/g in Ultrasound extraction. Likewise, the shell exhibited a promising amount of essential and non-essential amino acids. Conclusively, the peanut shell can be valorized due to its rich phytochemicals with special reference to luteolin.