Evaluation of the prebiotic potential of five kiwifruit cultivars after simulated gastrointestinal digestion and fermentation with human faecal bacteria

Abstract

Summary We studied the in vitro prebiotic potential of five different cultivars of kiwifruit including the green‐fleshed ‘Hayward’ and ‘Zesh004’ and the gold‐fleshed ‘Hort16A’, ‘Zesy002’ and ‘Zesy003’. The kiwifruit (25 g fresh weight equivalent) were subjected to simulated gastrointestinal digestion before fermentation for 16 h with faecal microbiota from ten individual donors. Microbial metabolites including lactate were quantified while changes in microbiome composition were determined by 16S rRNA sequencing. Lactate concentrations were highest with ‘Hayward’ (P = 0.01) and correlated with the amount of the kiwifruit fibre and polyphenols, chlorogenic acid and cryptochlorogenic acid. All the kiwifruit behaved similar to inulin in increasing the relative abundance of Bifidobacterium (P < 0.001), but unlike inulin, significantly (P < 0.001) increased the abundances of Ruminococcaceae and decreased Bacteroides. In comparison with inulin, the green‐fleshed kiwifruit selectively increased Lachnospira (P = 0.008) while the gold‐fleshed kiwi fruit increased Akkermansia (P < 0.001). These data suggest that the fibre and polyphenol content of the kiwifruit play a role in modulating gut microbial metabolism. Further clinical studies with these kiwifruit cultivars are required to confirm the potential prebiotic benefits that may be achieved by normal dietary intervention.

Bioaminergic Responses in an In Vitro System Studying Human Gut Microbiota–Kiwifruit Interactions

“…The fruit were sliced and coarsely blended to a puree. Then 50 g puree aliquots were subjected to a gastrointestinal digestion and fermentation protocol, as previously described [ 30 ]. Inulin and water were included as controls.…”

“…The feces, required for the fermentation, were obtained from four healthy donors who had not taken antibiotics for the last 3 months, with approval from the Central Health and Disabilities Ethics Committee, New Zealand (13/CEN/144, approved on 11 October 2013). Samples were processed within 30 min of voiding, and blended in chilled pre-reduced glycerol-buffered saline (10 mM phosphate, 150 mM NaCl, 10% v/v glycerol, 0.05% w/v cysteine, pH 7.2) to 20% fecal slurry stocks and stored at −80 °C, as described previously [ 30 , 34 ].…”

“…We have previously demonstrated that green and gold kiwifruit enhance bifidobacterial populations, and drive changes in the microbial consortium to generate a cocktail of beneficial OAs. The fiber and the polyphenol components of kiwifruit were associated with this probiotic paradigm in a previously studied in vitro gastrointestinal model [ 30 ]. Kiwifruit are also sources of BA such as GABA [ 31 ], 5-HT [ 27 ] and BA precursors such as GLU, PHE, TYR and TRP [ 32 ].…”

“…Green and gold kiwifruit peel flavonoids were also found to potentiate sleep via GABA-mediated pathways [ 31 ]. Furthermore, besides these bioaminergic interactions, both green and gold kiwifruit have been shown to modulate gut microbiota from the Firmicutes phylum, many species of which have been linked with the generation of bioamines [ 3 , 25 , 30 ].…”

Developments in understanding and applying prebiotics in research and practice—an ISAPP conference paper

“…SCFA production is often attributed exclusively to the fermentation of dietary fibre and prebiotics. However, an in vitro study using a simulated intestinal ecosystem found that SCFA production correlated with both the total fibre content and a range of polyphenolic compounds present in kiwifruit (Parkar et al ).…”