Prebiotic carbohydrate profile and in vivo prebiotic effect of pumpkin (Cucurbita maxima) grown in Sri Lanka

Abstract

This study was aimed at analysing the dietary fibre (DF) content and prebiotic carbohydrate profile of two local pumpkin varieties (Villachchi, Moragollagama) and five imported hybrid varieties (Arjuna, Suprima, Abishek, Lara, Pragathi) grown in Sri Lanka, and investigating the prebiotic potential of pumpkin powder in vivo using the pig as an animal model for human. High performance liquid chromatography (HPLC) technique was performed to identify the prebiotic carbohydrate profile. In the feeding trial, pigs were fed with standard diet (SD), pumpkin powder + SD (PD), SD+probiotics, and PD + probiotic. Freeze dried Bifidobacterium animalis subsp. lactis (500 mgday-1) and Lactobacillus acidophilus (500 mgday-1) were used as probiotic organisms. At the end of the experimental period, faecal microbial compositions of the pigs were analysed. Results revealed that the total DF content of pumpkin pulp did not vary (p > 0.05) among varieties. However, the local varieties had higher (p < 0.05) soluble DF (11.75 - 12.21 % dry matter) than the hybrid varieties. Mean concentrations of sorbitol, mannitol, stachyose + raffinose, verbascose + kestose and nystose of pumpkin were 106.7, 41.4, 76.5, 294.5 and 37.5 mg/100 g dry matter, respectively. Pumpkin powder fed pigs had higher (p < 0.05) counts of faecal lactic acid bacteria and bifidobacteria in comparison to SD fed pigs. In conclusion, this study revealed that pumpkin contains prebiotic carbohydrates, namely, sorbitol, mannitol, stachyose, raffinose, verbascose, kestose and nystose, and the feeding trial reflected prebiotic activity of pumpkin powder indicating a possibility to be used in functional foods.