Functional Properties of Aqueous Fruit Extracts Towards Probiotic and Pathogenic Bacteria
type: CreativeWork
description: Functional foods and ingredients provide health-promoting benefits to consumers in addition to their nourishing role. Exploitation of fruit ingredients that stimulate the growth of probiotic bacteria and suppress that of pathogenic bacteria could contribute to the success of health-promoting probiotic foods. This study investigated the functional properties of aqueous extracts of four New Zealand-grown fruits, namely, blueberry, strawberry, green kiwifruit, and feijoa, towards probiotic bacteria and food-borne pathogenic bacteria. The fruit extracts were prepared by homogenizing dried fruit pulp in sodium phosphate buffer (pH 7.4), followed by centrifugation and filtration. Prior to assay, the fruit extracts were sterilized by a two-step membrane filtration using 0.45 µm and 0.22 µm membrane filters. Before mixing the fruit extract with the bacteria, the bacteria were allowed to adapt to the growth medium using two sub-cultures and the cell concentration was standardized at103 cells/mL. Fruit extracts at 10%, 20%, and 30% were each used in a bioassay using a high-throughput method in a sterile 96-well microplate. A series of two-fold dilutions of the fruit extract was prepared resulting in an overall concentration range of 0.01 g/L to 30 g/L. The change in growth was calculated as ∆Growth values after reading the optical density (620 nm) in a microplate reader. The fruit extracts were used in the assay as single extract and as combined extracts. Results showed that the effect of the fruit extracts were dose- and species-dependent. At high concentrations, the four fruit extracts exerted growth-stimulating effect on the probiotic species of Bifidobacterium and Lactobacilli, except with Bifidobacterium longum. However, a biphasic effect was observed with strawberry, green kiwifruit and feijoa extracts, where at low concentrations, the extracts had growth-inhibiting effect on the probiotic bacteria while high concentrations had growth-stimulating effect. In contrast, al…
abstract: Functional foods and ingredients provide health-promoting benefits to consumers in addition to their nourishing role. Exploitation of fruit ingredients that stimulate the growth of probiotic bacteria and suppress that of pathogenic bacteria could contribute to the success of health-promoting probiotic foods. This study investigated the functional properties of aqueous extracts of four New Zealand-grown fruits, namely, blueberry, strawberry, green kiwifruit, and feijoa, towards probiotic bacteria and food-borne pathogenic bacteria. The fruit extracts were prepared by homogenizing dried fruit pulp in sodium phosphate buffer (pH 7.4), followed by centrifugation and filtration. Prior to assay, the fruit extracts were sterilized by a two-step membrane filtration using 0.45 µm and 0.22 µm membrane filters. Before mixing the fruit extract with the bacteria, the bacteria were allowed to adapt to the growth medium using two sub-cultures and the cell concentration was standardized at103 cells/mL. Fruit extracts at 10%, 20%, and 30% were each used in a bioassay using a high-throughput method in a sterile 96-well microplate. A series of two-fold dilutions of the fruit extract was prepared resulting in an overall concentration range of 0.01 g/L to 30 g/L. The change in growth was calculated as ∆Growth values after reading the optical density (620 nm) in a microplate reader. The fruit extracts were used in the assay as single extract and as combined extracts. Results showed that the effect of the fruit extracts were dose- and species-dependent. At high concentrations, the four fruit extracts exerted growth-stimulating effect on the probiotic species of Bifidobacterium and Lactobacilli, except with Bifidobacterium longum. However, a biphasic effect was observed with strawberry, green kiwifruit and feijoa extracts, where at low concentrations, the extracts had growth-inhibiting effect on the probiotic bacteria while high concentrations had growth-stimulating effect. In contrast, al…
author: Hap, Sophorn
keywords: Functional fruit extracts, Probiotics, Pathogens, High throughput assay
date published: 2010
date modified: 2026-07-27T18:46:06Z
provider: AUT University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: AUT University