Lactulose as a food ingredient英文电子书.pdf

Mini-review Received: 13 February 2009 Revised: 26 May 2009 Accepted: 27 May 2009 Published online in Wiley Interscience: 9 July 2009 () DOI 10.1002/jsfa.3694 Lactulose as a food ingredient ´ ∗ Agustın Olano and Nieves Corzo Abstract Lactulose is a synthetic ketose disaccharide that can be obtained from lactose by different methods of synthesis. Chemical methods are based on the isomerization of lactose in the presence of basic catalysts and enzymatic methods using lactose as a galactose donor and fructose as an acceptor. The prebiotic properties of lactulose have been known for more than 50 years and numerous studies have confirmed several health benefits of lactulose as a food ingredient, including selective stimulation of intestinal flora, laxative effect and improvement of calcium absorption. Its use in fermented milk manufacture may reduce the incubation period and favour the growth of bifidobacteria. The synthesis of lactulose-derived oligosaccharides may provide a new group of prebiotics with properties complementary to those of native lactulose. c 2009 Society of Chemical Industry Keywords: lactulose; synthesis; transgalactosylation; prebiotic INTRODUCTION cases the method is based on that of Montgomery and Hudson,6 Lactulose (4-O-β-D-galactopyranosyl-D-fructose) is a synthetic the only difference being the replacement of calcium hydroxide sugar, which does not occur naturally and is produced from by other basic catalysts such as alkaline hydroxides, sodium sulfite, lactose by isomerization in basic media using different types of ammonia or organic basic reagents such as tertiary amines.8,9 catalyst. Although lactulose is absent in raw milk, the dissolved salt These methods afford low yields and are te