Among potential health beneficial effects in vitro assessmen

Among potential health beneficial effects, in vitro assessment of fermented foods isolates for their hypocholesterolemic effect has been done by some researchers [16,31,45]. Cholesterol binding by LAB in the small intestine may reduce the amount of dietary cholesterol absorbed [31]. Several mechanisms for lowering cholesterol dgat inhibitor have been hypothesized [46], including enzymatic deconjugation of bile acids by bile-salt hydrolase (BSH), assimilation of cholesterol, co-precipitation of cholesterol with deconjugated bile, binding of cholesterol to the cell walls of probiotic bacteria, incorporation of cholesterol into the cell membranes of probiotics, conversion of cholesterol to coprostanol, and production of short-chain fatty acids by probiotics in the presence of prebiotic substrates. BSH hydrolyzes conjugated glycodeoxycholic acid and taurodeoxycholic acid, leading to the deconjugation of glyco- and tauro-bile acids. Once deconjugated, bile acids are less soluble and absorbed by the intestines, leading to their elimination in the feces. Cholesterol is used to synthesize new bile acids in a homeostatic response, resulting in lowering of serum cholesterol. The ability of cholesterol-binding appeared to be growth and strain specific. Other potential health benefits shown by LAB isolates from fermented foods are the ability of a L. plantarum isolate from dadih to remove microcystin-LR, a cyclic heptapeptide hepatoxin produced by cyanobacteria [47] and the ability to produce β-glucosidase [48,49]. Cyanobacteria produce a number of potent hepato- and neurotoxins, collectively called cyanotoxins, which have potent acute hepatotoxicity and tumor promoting activity [47]. Lb. plantarum IS-10506 and IS-20506 have shown ability to efficiently remove the toxins. Meanwhile, β-glucosidase activity is widespread among LAB and presumably plays a role in interactions with the human host [50]. β-Glucosidase releases a wide range of plant secondary metabolites from their β--glucosylated precursors. The conversion of glucoside isoflavones into their bioactive aglycones by LAB has been observed in soymilk fermentation [48]. LAB isolated from fermented foods has potential as producers of bioactive compounds. Gamma-aminobutyric acid (GABA) has various physiological functions and could be produced by LAB [54]. Some Lactobacillus species have been reported to produce equol [7-hydroxy-3-(40-hydroxyphenyl)chroman], a nonsteroidal estrogen of the isoflavone class in fermented soymilk [55]. Most established probiotics are LAB and Bifidobacteria although recently certain yeasts (e.g. Saccharomyces boulardii[56–58]) and spore-forming bacteria (e.g. Bacillus coagulans[59–61]) have been considered as probiotics. While S. boulardii has been shown to be effective in preventing the recurrence of Clostridium difficile-induced pseudomembranous colitis as well as the antagonistic action of E. coli, the long-term advantages of using spores as probiotics is that they are heat-stable and can survive transit across the stomach barrier, properties that cannot be assured with other probiotic bacteria that are given in the vegetative form [61]. Yeasts are commonly present in many fermented foods [6,11,12,62] and starter culture [63]. Spore-forming bacteria could also be part of the microbial consortium in traditional Indonesian fermented foods, such as tempe [5] and tape [6,64] as well as their starter cultures [62].
Health beneficial effect of lactic acid bacteria isolated from fermented foods
Future perspectives Exploration of potentially beneficial microorganisms in Indonesian fermented foods needs to be extended to microorganisms other than LAB that are also present in fermented foods. Yeasts and some species of Bacillus for examples are the potential microorganisms for probiotic.
Acknowledgement
Introduction Food fermentation and the consumption of fermented foods date far beyond human civilization. The transition from hunting and gathering to an agricultural lifestyle might have contributed to the further development of these food fermentations that are now practiced on industrial scales. However, human interactions with probiotics are more intimate and have a much longer history than the historic food fermentations. All parts of the human body such as the skin, oral cavity, gastrointestinal tract, and vaginal cavity are inhabited by trillions of microbes [1,2]. At birth, the human gut is sterile but colonized immediately after birth [3]. Factors such as the type of delivery (vaginal birth versus cesarean section) and the type of diet (breast feeding versus formula feeding) affect the colonization patterns [4]. The pioneer microbes that ‘infest’ the gut make permanent adaptations and determine the physiological, immune, metabolic and behavioral development and also influence future disease susceptibility [132]. Age and life style are some causes of many disease conditions since they contribute to alterations in the microbial flora in the body [5]. Recent studies have demonstrated that bacterial community composition is considerably altered in diseases such as obesity and periodontal disease, with healthy subjects usually exhibiting distinct, diverse and temporally stable bacterial populations at these sites when compared with patients displaying disease symptoms [6]. As consumers become aware of the impact of what they eat on their health, they tend to search for functional foods. Attention has been paid to prevention of diseases than cure and hence, probiotic containing foods are abundant on the market.