Changes in Bioactive Compounds Over Lactic fermentation
- 1. Changes in Bioactive Compounds Over Lactic fermentation Sukhveer Singh Ph.D.-FST
- 2. The increase of nutrient density by lactic fermentation is mostly due to a decrease of sugar content. Catabolism of disaccharides like sucrose or lactose has been extensively studied for many LAB species (Gänzle & Follador, 2012; Melanie Kostinek et al., 2005; Lynch et al.,2015). On the opposite, sucrose, glucose and fructose were totally depleted over cabbage or leek fermentation when fermentation lasted several weeks (Jung et al., 2013; Wouters, Bernaet, et al., 2013; Wouters, Grosu-Tudor, Zamfir, & De Vuyst, 2013). Fermentation also contributes to increase protein, peptides and amino acid content in foods from legumes. Increase of nutrient density
- 3. One of the main mechanism that could explain antioxidant activity variation is the release of bioactive compounds from conjugated phytochemicals. Feruloyl esterase enzymes are also known as ferulic acid esterases (FAE), cinnamoyl esterases and cinnamoyl ester hydrolases, release ferulic acid or coumaric acid from conjugated phenolic acids. Beta-glucosidase is one of the major enzymes responsible for the hydrolysis of flavonoid conjugates during bacterial fermentation. This enzyme was detected in many LAB species (Lee, Han, & Kim, 2012; Michlmayr & Kneifel, 2014; Pyo, Lee, & Lee, 2005). Hydrolysis of phenolic compounds
- 4. Cabbage content in glucosinolates is high (Kusznierewicz et al.,2008). The main glucosinolates hydrolysis product in fermented cabbage is Ascorbigen. It was shown recently that cabbage fermentation by LAB resulted in an increase of antioxidant activity (Kusznierewicz, Śmiechowska, Bartoszek, & Namieśnik, 2008). The observed changes can be related to Lactobacillus ability to degrade glucosinolate in allyl-isothiocyanate (Llanos Palop, Smiths, & Brink, 1995). Derivatives of glucosinolates
- 5. Bioactive peptides have been mainly studied from milk or whey hydrolysis during lactic fermentation (López-Fandiño, Otte, & van Camp, 2006). But also from fermented soybeans (Gibbs, Zougman, Masse, & Mulligan, 2004), and more recently from grapes (Aredes Fernández, Stivala, Rodríguez Vaquero, & Farías, 2011) and cereal flours (Coda, Rizzello, Pinto, & Gobbetti, 2012). Bioactive peptides are generated during fermentation process through enzymatic proteolysis, performed by single or multiple, specific or unspecific proteases, of larger protein molecules usually not bearing any bioactivity (Humiski & Aluko, 2007). Bioactive peptides
- 6. Secondary metabolites generated during fermentation process are notably interesting regarding health. Isoflavones from soya, for example, were demonstrated with anti-cancer properties, limiting the onset of breast carcinogenesis (Celligoi, Santos, da Silva, & Baldo, 2015). Short chains fatty acids are produced from hydrolysis of lipids. Fermentation of fruits and vegetables is frequently associated with an increased content in vitamins. They notably include vitamins of the B group as well as others such as vitamin K. Secondary metabolites, short chain fatty acids and vitamins
- 7. It was demonstrated that LAB belonging to the genera Lactobacillus, Lactococcus, Leuconostoc, Pediococcus and Weissella, in particular W. cibaria, W. confusa and W. hellenica, are producing a large diversity of EPS, depending on the carbon source (Fessard et al., 2016; Juvonen et al., 2015; M. J. Kim, Seo & Park, 2008; Pan & Mei, 2010). The most studied health effect is indirect and called prebiotic: EPS stimulate the growth of probiotic bacteria. EPS are also proposed to have direct effects, such as immunomodulation effects, antioxidant activity and cancer prophylaxis (Caggianiello, Kleerebezem, & Spano, 2016; Franco-Robles & López, 2015; Kwak, Cho, Noh, & Om, 2014; Pan & Mei, 2010). Synthesis of exopolysaccharides
- 8. The content of proteases and trypsin inhibitor was also reduced by fermentation. LAB, through their enzymatic equipment, help neutralize anti-nutritive factors such as phytates, saponins, tannins, cyanogens or trypsin inhibitors. (Lai, Hsieh, Huang, & Chou, 2013). For example, galactosidase is able to reduce anti-nutritive factors such as phytic acid, tannins, trypsin inhibitors (Adeyemo & Onilude, 2014). This effect can be associated with modification of minerals bioavailability (Arslan & Erbas, 2015; Gaspar & Crespo, 2015) and proteins whose digestibility is also favored (Kaur, Jha, Sabikhi, & Singh, 2014). Degradation of anti-nutritional factors
- 9. Use of probiotic bacteria in the non-dairy product is challenging and important to research and industry for commercialisation of healthy beverage. Masking of the medicinal taste and off flavours is the possible solution for the nondairy probiotic. Probiotic cells can be stabilized with microencapsulation to preserve them from detrimental processing and storage factors such as high acidity and low pH. Lactic fermentation modifies the composition of the fermented materials and by the metabolic microbial action can improve the beneficial health benefits of food. CONCLUSION
- 10. Food is our natural medicine