Valorisation of pineapple peel waste as natural surimi gel enhancer and its optimization in Nile tilapia (Oreochromis niloticus) surimi gels.

This investigation explored the preparation of surimi gel enhancer from pineapple peel waste, hugely generated by industries and spreading serious environment pollutions. The peel extracted with 100% ethanol had higher bioactive and antioxidant attributes, which was subsequently fortified in tilapia surimi at levels of 0.20%-1.20%, w/w to improve its physiochemical, textural, protein structural and sensorial properties. Our finding demonstrated that surimi gels enriched with 0.80% ethanolic pineapple peel extract (PAPE) exhibited significant (p<0.05) improvement in water holding capacity, breaking force, gel strength, and other textural properties and sensory attributes. Furthermore, the surimi gels fortified with 0.80% PAPE exhibited the elevated levels of hydrogen and hydrophobic interactions, while sulfhydryl and free amino acid contents demonstrated a contrasting trend. The FTIR spectra displayed that the incorporation of PAPE influenced the secondary structure of the protein, as evidenced by shifts in the α-helix to β-sheet peaks. In addition, 0.80% PAPE added gels displayed a compact, uniform, and organized microstructure, featuring small cavities. In summary, the fortification of tilapia surimi gels with 0.80% PAPE could improve gelling and other technological properties with higher sensory scores. This study offers an effective approach to utilize the pineapple peel as a gel enhancer additive for the development of functional surimi and surimi-based products enriched with bioactive compounds.