**3. Functional compounds bio-produced using lactose as substrate**

#### **3.1 Biocatalytic processes**

#### *3.1.1 Galacto-oligosaccharides*

Galacto-oligosaccharides [Gal-(Gal)n-Glu] are lactose-derived non-digestable oligosaccharides (GOS) recognized as relevant functional compounds. Industrially, GOS are produced using CW lactose as substrate through biocatalytic reaction. Lactose is transgalactosylated by ß-galactosidases enzymes (E.C. 3.2.1.23) from several microbial strains [44]. GOS are the best substitute for human oligosaccharides, have a sweet taste, low energy value (2 kcal/g), as well as tolerate high temperatures and low pHs. So, they are widely used in the food industry as functional ingredient in the manufacturing of infant formula, confectionary, chewing gum, yogurt, ice cream and bakery products [45].

Previous studies have demonstrated the impact of GOS promoting gut health and well-being. These lactose-derived prebiotics serve as substrates for the microbiota, improve saccharolytic metabolic activities and stimulate the growth of indigenous bifidobacteria and lactobacilli. In consequence, the formation of volatile fatty acids, lowering of the luminal pH and decreased formation of toxic secondary bile acids are microbial metabolic associated effects. Also, they inhibit the formation of toxic bacterial metabolites, such as ammonia, hydrogen disulphide, phenolic compounds and biogenic amines [44]. Moreover, GOS have a bifidus factor similar to the effect of human milk oligosaccharides stimulating the growth of specific intestinal microbiota, improving the intestinal motility, enhancing immunity, promoting the synthesis of vitamins, reducing the high levels of cholesterol and triglycerides and decreasing the risk of colon cancer development [45, 46].

#### *3.1.2 Lactosucrose*

Lactosucrose is an oligosaccharide comprising Gal, Fru and Glu. This carbohydrate molecule (C18H38O16; MW, 510.4 g/mol) is a ß-D-fructofuranosyl-4-O- ß-Dgalactopyranosyl-α-D-glucopyranoside [16]. Lactosucrose can be regarded as a condensate of sucrose and galactose molecules or lactose and fructose molecules. Production protocols include transferring the ß -galactosyl group produced by the decomposition of lactose to the C4 hydroxyl group of glucosyl in sucrose by the

**81**

*Value-Added Compounds with Health Benefits Produced from Cheese Whey Lactose*

enzymatic activity of ß-galactosidase (E.C. 3.2.1.23). Also, it can be produced by the catalysis of ß-fructofuranosidase (E.C. 3.2.1.26) or levansurase (E.C. 2.4.1.10) transferring the fructose group generated by the decomposition of sucrose to the C1 hydroxyl group at the reducing end of the lactose. Industrially, ß-fructofuranosidase is one of the most common enzymes used to the production of lactosucrose due to its availability and low cost [47]. This non-reducing trisaccharide is an ingredient of cosmetic and pharmaceutical products. Moreover, it is widely used in a large number of functional foods. In fact, in Japan, lactosucrose has the status of FOSHU ingredient. So, it has been used in a large number of healthy foods and drinks, such as bakery products, yogurt, ice creams, infant formula, chocolates, juice and

In the last decades, the demand for lactosucrose has significantly increased. This

Lactic acid bacteria (LAB) play a key role in the fermentation processes of food worldwide. These group of microorganisms improve the preservation, enhance sensory characteristics, increase nutritional values of a large variety of food and beverages products and have been recognized by their health-promoting attributes [49]. Several LAB have the ability to produce exopolysaccharides (EPS) as cell wall constituents named peptidoglycan located in the extracellular medium without covalent bounds with bacterial membrane [49, 50]. EPS are a diverse group of high-molecular-mass polysaccharides in terms of chemical composition, quantity, molecular size, charge, presence of side chains rigidity of the molecules, including

LAB-EPS are classified depending on the composition of the main chain and their mechanisms of synthesis. They can be divided into homopolysaccharides (HoPs) or heteropolysaccharides (HePs) In general, HoPs contain only one type of monosaccharide (glucose or fructose) through linear or branched α or β links,

liter by *Lactobacillus*, *Leuconosctoc*, *Oenococcus* and *Weissella* extracellularly from sucrose or starch without noncarbohydrate groups. On the other side, HePs contain more than one type of monosaccharide, mainly glucose, galactose and rhamnose

Most of them are produced in milligrams per liter by *Lactobacillus*, *Lactococcus*, *Bifidobacterium* and *Streptococcus* from intracellular intermediates with the presence

Kefiran is the main HePs synthetized by kefir grains microorganisms. Kefir grains are a consortium of symbiotic LAB, acetic acid bacteria, bifidobacteria and yeast microorganisms embedded in a matrix of proteins, lipids, polysaccharides and water [52] . These microorganisms are able to synthetize kefiran from CW lactose even if it is deproteinized [53]. In fact, using CW lactose as a fermentation

together through α and β links, typically branched with 104

Da molecular mass. These EPS are produced in grams per

–106

Da molecular mass.

can be explained by the widely uses of it in the preparation of functional foods. Lactosucrose is well known by its prebiotic effect. *In vivo* studies in animals, as well as in humans have demonstrated the association between lactosucrose consumption and health-promoting effects. Their review includes enhancement of beneficial bacteria and or inhibition of pathogenic microorganisms, decrease of fecal pH, production of short chain fatty acids and gases, reduction of putrefactive products, enhancement of intestinal absorption of minerals, treatment of chronic inflammatory bowel diseases, normalization of intestinal microflora and prevention of

*DOI: http://dx.doi.org/10.5772/intechopen.94197*

abdominal symptoms of lactose intolerance [48].

*3.2.1 Lactic acid bacteria exopolysaccharides (LAB-EPS)*

mineral water [48].

**3.2 Microbial bioprocesses**

mechanisms of synthesis [49, 51].

of noncarbohydrates groups [51].

with more than 106

#### *Value-Added Compounds with Health Benefits Produced from Cheese Whey Lactose DOI: http://dx.doi.org/10.5772/intechopen.94197*

enzymatic activity of ß-galactosidase (E.C. 3.2.1.23). Also, it can be produced by the catalysis of ß-fructofuranosidase (E.C. 3.2.1.26) or levansurase (E.C. 2.4.1.10) transferring the fructose group generated by the decomposition of sucrose to the C1 hydroxyl group at the reducing end of the lactose. Industrially, ß-fructofuranosidase is one of the most common enzymes used to the production of lactosucrose due to its availability and low cost [47]. This non-reducing trisaccharide is an ingredient of cosmetic and pharmaceutical products. Moreover, it is widely used in a large number of functional foods. In fact, in Japan, lactosucrose has the status of FOSHU ingredient. So, it has been used in a large number of healthy foods and drinks, such as bakery products, yogurt, ice creams, infant formula, chocolates, juice and mineral water [48].

In the last decades, the demand for lactosucrose has significantly increased. This can be explained by the widely uses of it in the preparation of functional foods. Lactosucrose is well known by its prebiotic effect. *In vivo* studies in animals, as well as in humans have demonstrated the association between lactosucrose consumption and health-promoting effects. Their review includes enhancement of beneficial bacteria and or inhibition of pathogenic microorganisms, decrease of fecal pH, production of short chain fatty acids and gases, reduction of putrefactive products, enhancement of intestinal absorption of minerals, treatment of chronic inflammatory bowel diseases, normalization of intestinal microflora and prevention of abdominal symptoms of lactose intolerance [48].
