title: Soybean whey enhance mineral balance and caecal fermentation in rats.
abstract: BACKGROUND
  Soybean whey, a by-product of tofu manufacturing, is currently discarded by the food industry. However, it contains valuable compounds such as non-digestible oligosaccharides (NDO), which promote the growth of beneficial lactic acid bacteria in the colon, and are therefore recognized as prebiotics. Acidic fermentation of NDO in the caecum appears to be related with an increase in mineral absorption.
  
  
  OBJECTIVE
  To evaluate the effect of consuming soybean whey containing galacto-oligosaccharides (GOS) on mineral absorption and caecal fermentation in rats.
  
  
  METHODS
  An in vivo assay was carried out in rats over a period of 4 weeks; previously, the nutritional composition of soybean whey was determined and NDO were measured by high-performance liquid chromatography (HPLC). Faeces and urine were collected weekly throughout the experiment for mineral balance analyses. Animals were killed under anaesthesia, organs were removed and weighed, and short-chain fatty acids in the caecal contents were determined by gas chromatography.
  
  
  CONCLUSIONS
  Non-digestible carbohydrates such as GOS stachyose (318 +/- 3 mg/100 mL) and traces of inulin were identified by HPLC. When soybean whey was used as a source of GOS in rats, the consumption of diluted soybean whey (75 mL/day per rat) containing GOS (120 mg/day per rat) exhibited a prebiotic effect and led to an improved mineral balance, especially for calcium and magnesium. In view of its composition and potential health-promoting properties, soybean whey could be used as a valuable ingredient in new functional foods.
authors.affiliation: Nutrición y Bromatología II Department, Universidad Complutense, Madrid, Spain.
authors.forename: María Dolores
authors.initials: MD
authors.lastname: Tenorio
authors.forename: Irene
authors.initials: I
authors.lastname: Espinosa-Martos
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Préstamo
authors.forename: Pilar
authors.initials: P
authors.lastname: Rupérez
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002136:Calcium, Dietary / Q000378:metabolism; D002432:Cecum / Q000187:drug effects / Q000378:metabolism*; D002849:Chromatography, Gas; D003300:Copper / Q000378:metabolism; D005260:Female; D005285:Fermentation / Q000187:drug effects*; D007408:Intestinal Absorption / Q000187:drug effects*; D019266:Iron, Dietary / Q000378:metabolism; D008274:Magnesium / Q000378:metabolism; D008903:Minerals / Q000378:metabolism*; D009929:Organ Size / Q000187:drug effects; D056692:Prebiotics; D051381:Rats; D017208:Rats, Wistar; D013025:Glycine max; D013997:Time Factors; D015032:Zinc / Q000378:metabolism
chemical_list: D002136:Calcium, Dietary; D019266:Iron, Dietary; D008903:Minerals; D056692:Prebiotics; D003300:Copper; D008274:Magnesium; D015032:Zinc