بررسي ميزان بقاء لاكتوباسيلوس پلانتاروم A7 ريز پوشينه دارشده در ماست و در شرايط شبيه سازي شده گوارشي

چكيده انگليسي :

150 Investigation of Viability of Microencapsulated Lactobacillus plantarum A7 in Yoghurt and in Simulated Gastrointestinal Condition Zahra Ghasemi zahra ghasemi@agr iut ac ir March 3 2012 Department of Food Science and Technology Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiMahmoud Sheikhzeinodin zeinodin@cc iut ac irMohammad Fazilati fazilati@cc iut ac irAbstractFunctional foods containing viable probiotic bacteria are being increasingly produced for their health benefits Manystudies have shown that the viability of probiotic bacteria in dairy products and in human s gastrointestinal tract condition GTC is low Microencapsulation of probiotic bacteria with sodium alginate and improving the microcapsule s proper ties by special treatments such as coating with other polymers could increase the viability of probiotics in food productsand in GTC In this study the native probiotic Lactobacillus plantarum A7 was encapsulated into uncoated calciumalginate beads ALG and the same beads were coated with whey proteins ALCW and sodium alginate ALCA Aver age size and morphological characteristics of the microcapsules were evaluated by light reflection microscope and Scan ning Electron Microscope SEM The survival of free uncoated and coated microencapsulated cells of Lactobacillusplantarum A7 was tested in saline solution and yoghurt during 50 days of storage at 4 C Moreover pH changes weremonitored during storage time and the sensory properties of yoghurts were investigated by panelists Viability of free uncoated and coated microencapsulated cells were tested in simulated gastric juice SGJ and simulated intestinal juice SIJ before inoculation in yoghurt and at the end of storage period Average size of ALG ALCA and ALCW was77 24 14 88 79 20 19 50 and 80 70 16 97 m respectively Results showed that all microcapsules had a sphericalshape and smooth surface Cross sections of ALCW beads revealed the random distribution of bacteria throughout thealginate network Decrease of pH in yoghurt samples containing coated and uncoated microcapsules during fermentationwas slower than that in the control yoghurt sample yoghurt without probiotic bacteria and yoghurt containing free ornormal cells Moreover the results also showed that the post acidification of yoghurts containing coated and uncoated microcapsules was slower than that in the control yoghurt sample and yoghurt containing free cells Sensory evaluationrevealed that the free and microencapsulated cells of probiotics did not affect the sensory properties of yoghurts duringstorage period Under refrigerated storage viability of microencapsulated cells in saline solution and in yoghurts weregreatly enhanced compared to that in the free cells and the treatments showing the lowest loss of viability were those ofALCW and ALCA The population of microencapsulated cells in ALG ALCA and ALCW in the yoghurt was consistentwith a minimum acceptable amount of cell population in dairy products minimum 10 7 109 CFU per gram or milliliterproduct at the end of storage period Viability of Lactobacillus plantarum A7 in saline solution and in yoghurt revealedthat loss of free and immobilized cells in yoghurt was lower than that in saline solution The simulated gastrointestinalmedium SGT drastically reduced the viability of free uncoated and coated microencapsulated cells of both saline solu tion and yoghurt with significant differences between free and coated microencapsulated cells p 0 05 Viability ofimmobilized cells in SGT was greatly enhanced compared to that in the free microorganisms and the treatments ofALCW and ALCA showed the lowest loss of viability Results also showed that if free and microencapsulated cells priorto inoculation in the SGT is kept in yoghurt for 50 days their viability improves significantly compare to those trans ferred directly from the saline solution to SGT Moreover the resistance of free and immobilized cells in simulated gas tric juice SGJ seems

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بررسي ميزان بقاء لاكتوباسيلوس پلانتاروم A7 ريز پوشينه دارشده در ماست و در شرايط شبيه سازي شده گوارشي

پروبيوتيك , ريز پوشاني , پوشش دهي , پروتئين هاي آب پنير , محيط شبيه سازي شده گوارشي