Should you add kiwifruit to your cereal? The effect of purified actinidin from green kiwifruit on oat bran proteins and the subsequent generation of bioactive oat peptides : A dissertation submitted in partial fulfilment of the requirements for the Degree of Master at Lincoln University

Abstract

Purified actinidin was added to Oat bran protein to investigate the bioactivity of peptides generated before and after in vitro gastrointestinal digestion. Actinidin purification was conducted using ion-exchange chromatography. Ferric antioxidant power (FRAP) and Total phenolic concentration (TPC) analysis was conducted post in vitro digestion. Dialysate prepared from commercial kiwifruit powder (External) had a 1.65 fold higher specific enzyme activity than freeze-dried fresh kiwifruit powder (In-house). Actinidin specific activity (External) increased from 2.61 ± 0.57 U/mg to 196.53 ± 36.45 U/mg due to purification. Purified actinidin showed a molecular weight of 25 kDa on NuPAGE. After in vitro digestion, a significant increase (p < 0.05) was observed in FRAP and TPC for Oat bran protein + Purified actinidin compared to Oat bran protein. These results suggest after in vitro digestion a greater amount of bioactive peptide were produced when expose Purified actinidin to Oat bran protein.