Probiotics, Prebiotics, and Synbiotics

One way in which foods are modified to become functional is by incorporating probiotics, prebiotics, or synbiontics (Gobbetti et al., 2010; Granato et al., 2010; Kumar et al., 2015). According to the FAO/WHO,probiotic are defined as “live microorganisms that,

Schematic overview of bioactive functions associated with dairy products

Figure 2.2.1.1 Schematic overview of bioactive functions associated with dairy products.

when administered in adequate amounts, confer a health benefit on the host,” while prebiotic is “a nonviable food component that confers a health benefit on the host associated with modulation of the microbiota.” Probiotics are also used in combination with prebiotics (synbiotics) to improve the microbial cell viability since prebiotics often act as entrapping matrices during the gastrointestinal transit, further releasing the microorganism in the intestine and then serving as fermentable substrates (Koh et al., 2013; Fernandez et al., 2015). A list of microorganisms and substances is available in the public registry by the EC (http://ec. europa. eu/food/food/biotechnology/novelfood/ nfnetweb/mod_search/index.cfm). For microorganisms added into foods, there is an annually updated list of microbes intentionally added to foods (QPS, Qualified Presumption of Safety of Microorganisms in Food and Feed, list), and this list forms the basis of organisms at the species level that are considered safe for foods in European Union (EFSA 2013).

A number of health benefits are claimed in favor of foods containing probiotic microorganisms, especially lactobacilli and bifidobacteria. These benefits mainly include antimutagenic effects, anticarcinogenic properties, improvement of lactose metabolism, antimicrobial activities, and reduction in serum cholesterol and immune system stimulation (Gobbetti et al., 2010). There are evidences of benefits and limitations under various medical and

health-related areas: (i) control of intestinal inflammation and therapeutic role in gastroenterology; (ii) maintenance of remission in Crohn's disease; (iii) improvement of human health and control of antibiotic-related diarrhea; (iv) control of infections during pregnancy and prevention of urinary tract infections; (v) management of allergic diseases; and (vi) several other medical applications (O'Flaherty and Klaenhammer, 2010). Some of these benefits are well established, while others have shown promising results only in animal models. Comprehensive reviews (e.g., Shah, 2007; De Vrese and Schrezenmeir, 2008) have focused on the effects of probiotics, prebiotics, and synbiot- ics on the human health. To realize health benefits, probiotic bacteria have to be viable and available at high cell densities (at least 6 log cfu/g) and prebiotics, short-chain carbohydrates, must be nondigestible by digestive enzymes in humans and selectively enhance the activity of some groups of beneficial bacteria in the gut (Al-Sheraji et al., 2013).

Milk and related dairy products (fermented milks, ice cream, cheeses) play an important role in the beneficial health effects of probiotics on the host and, consequently, they are commonly used as probiotic carriers (Araujo et al., 2012; Homayouni et al., 2012; Fernandez et al., 2015; Mocanu and Botez, 2012; Granato et al., 2010). Table 2.2.1.1 lists some milk-based probiotic products that have received consumer acceptance. When probiotic strains are selected for production of dairy foods, they must maintain an elevated cell viability before consumption and they must not be detrimental to sensory (e.g., texture, color, flavor) attributes.

Fermented milks have long been used as the main carrier for probiotic strains. Less frequently, cheeses are used for incorporation of probiotics, but they may offer a number of advantages compared with fermented milks (Fortin et al., 2011). Recently, heat- resistant probiotic lactobacilli were selected and added to Fior di latte (high-moisture cow milk Mozzarella) cheese (Minervini et al., 2012). Microbiological, compositional, biochemical, and sensory analyses showed that the use of probiotic Lactobacillus

Table 2.2.1.1 Some Probiotic Dairy Products Developed Worldwide (adapted from Granato et al., 2010).

Dairy products containing probiotics

Reference

Acidophilus milk drink

Itsaranuwat et al. (2003)

Synbiotic acidophilus milk

Amiri et al. (2008)

Regular full-fat yogurts

Aryana and Mcgrew (2007)

Low-fat yogurts

Penna et al. (2007)

Stirred fruit yogurts

Kailasapathy et al. (2008)

Dairy fermented beverage

Almeida et al. (2000)

Whey-protein-based drinks

Lucas et al. (2004);Dalev et al. (2006)

Biogarde, mil-mil, and acidophilus milk with yeasts

Gomes and Malcata (1999)

Cheddar cheese

Ong and Shah (2009)

Minas Fresco cheese

Souza and Saad (2009)

Feta cheese

Kailasapathy and Masondole (2005)

Cheese from caprine milk

Kalavrouzioti et al. (2005)

Kazar cheese

Ozer et al. (2008)

Semi-hard reduced-fat cheese

Thage et al. (2005)

White-brined cheese

Yilmaztekin et al. (2004)

Cottage cheese

Blanchette et al. (1996)

Canestrato Pugliese hard cheese

Corbo et al. (2001)

Argentinian fresco cheese

Vinderola et al. (2000)

Goat semi-solid cheese

Gomes and Malcata (1999)

Petit-Suisse cheese supplemented with inulin and/or oligofructose

Cardarelli et al. (2008)

Crescenza cheese

Gobbetti et al. (1997)

Manufacture of Turkish Beyaz cheese

Kili? et al. (2009)

Fior di Latte Mozzarella cheese

Minervini et al. (2012)

Synbiotic ice cream

Homayouni et al. (2008)

Probiotic ice cream

Kailasapathy and Sultana (2003);Akin et al. (2007)

Low-fat ice cream

Haynes and Playne (2002);Akalin and Erisir (2008)

Acidophilus milk-based ice cream

Andrighetto and Gomes (2003)

Dahi

Yaday et al. (2007)

Non-fermented goat’s milk beverage

Neves (2000)

Fermented goat’s milk

Martin-Diana et al. (2003)

Acidophilus butter and progurt

Gomes and Malcata (1999)

Frozen yogurt

Davidson et al. (2000)

Fermented lactic beverages supplemented with oligofructose and cheese whey

Castro et al. (2009)

(Continued)

Table 2.2.1.1 (Continued)

Dairy products containing probiotics

Reference

Traditional Greek yogurt

Maragkoudakisa et al. (2006)

Banana-based yogurt

Sousa et al. (2007)

High pressure-homogenized probiotic fermented milk

Patrignani et al. (2009)

Graviola and cupuassu-based yogurts

Silveira et al. (2007)

Acpai yogurt

Almeida et al. (2008)

delbrueckii ssp. bulgaricus SP5 and Lactobacillusparacasei BGP1 enhanced flavor formation and shelf life of Fior di latte cheese.

Other carriers that could be used to deliver probiotics are ice cream and frozen dairy desserts. These products are stored at low temperatures, increasing the cell viability of probiotics during storage (Cruz et al., 2009) and are consumed by people of all ages. Some prebiotics could be used to improve the characteristics of the probiotic ice creams (Al-Sheraji et al., 2013). The addition of inulin in ice cream enhanced the viability of Lactobacillus acidophilus and Bifidobacterium animalis ssp. lactis (Akin et al., 2007). The addition of oligofructose in low-fat ice cream also increased the viability of L. acidophilus La-5 and B. animalis ssp. lactis BB-12 (Akalin and Erisir, 2008).

Overall, the mixtures of probiotics and prebiotics are often used in order to take advantage of their synergic effects in application to dairy products. Synbiotics such as Raftilose® P95 (based on oligosaccharides and Lactobacillus rhamnosus, Bifidobacterium spp., L. acidophilus, and Lactobacillus casei) showed improved survival of probiotic bacteria at 4°C for 4 weeks of storage, compared to the formulation without oligosaccharides (Capela et al., 2006). Within prebiotics, lactulose, galacto oligosaccharides, fructooligosaccharides, inulin and its hydrolysates, maltooligosaccharides, and resistant starch are prebiotics normally used in functional products for human diet (Al-Sheraji et al., 2013). The essential end-components of carbohydrate metabolism are short-chain fatty acids, such as acetic, propionic and butyric acids, which are beneficial for human mucosa. In addition to the trophic role, preferentially, for probiotic bacteria (bifidobacteria and lactic acid bacteria), prebiotics increase the absorption of calcium and magnesium, influence blood glucose levels, and improve plasma lipids. Their use also improves sensory characteristics such as taste and texture of dairy products. For example, inulin is also used as fat replacer in low-fat cheeses (Al-Sheraji et al., 2013).

 
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