Prebiotic ALPINA GOS produced from whey permeate has a bifidogenic effect on the adult fecal microbiota in vitro, including stimulation of organic acids production

Abstract

Functional oligosaccharides, such as galacto-oligosaccharides (GOS), are valued for modulating gut microbiota and promoting health. This study aimed to produce a high-purity GOS ingredient (ALPINA GOS) via nanofiltration/diafiltration and assess its prebiotic efficacy using an in vitro fermentation model. GOS-rich syrup was obtained from transgalactosylation of lactose in concentrated whey permeate (30% lactose) and processed by diafiltration/nanofiltration to reduce monosaccharides and enrich oligosaccharide content. Carbohydrate composition was analyzed by HPAEC-PAD. Prebiotic activity was evaluated using a MicroColon model with fecal inocula from healthy adults, measuring pH, short-chain fatty acids (SCFAs), and microbiota shifts. Membrane processing increased oligosaccharides from 55.5% to 70.2% (dry basis) and reduced monosaccharides from 25.2% to 5.1%. ALPINA GOS induced a dose-dependent pH reduction and significantly enhanced lactate and acetate production, with stronger effects at 10 mg/mL. Microbiota profiling showed increased abundance of beneficial bacteria, especially Bifidobacterium, versus control. The findings confirm that GOS can be sustainably produced from whey permeate and exhibits potent prebiotic activity, supporting its application in functional foods aimed at gut health.