Browsing by Subject "Encapsulation"
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ItemEffect of encapsulation on Zymomonas mobilis survival rate from practical conditions and its levan polysaccharide production abilityBioethanol is one of the good sources of liquid energy for automobiles and industries. The bioethanol market has continued to grow rapidly in recent years. Thai government aims to increase ethanol consumption from 1.2 billion liters in 2015 to 3.3 billion liters by 2021 and up to 4.1 billion liters by 2036. Z. mobilis, a gram-negative bacterium, is considered as an alternative organism in large-scale fuel ethanol production. The bacterium Z. mobilis is a highly potent ethanol producer already used in industrial-scale fermentations which converts sugars to ethanol and carbon dioxide. Levans are natural polymers of the sugar fructose found in many plants and microbial products. They are formed as an undesirable by-product of sugar juice processing. This project aimed to study survivor rate of Z. mobilis encapsulated at different concentration of sodium alginate 2%, 2.5% and 3%., from simulated practical conditions including simulated food tract condition (acidic pH at 1.55 and 0.6% bile salt) and high temperature environment (85°). The encapsulated beads were separated into four different sizes according to their average size by sieving process. Results indicated that survival rates of encapsulated cells of Z. mobilis were significantly higher (p < 0.05) from all simulated conditions compared to free cells. Furthermore, the highest survival rate was obtained from sieve 10 with 3% sodium alginate for both heat and bile salt tests, while the lowest survival rates were performed by 2% alginate beads obtained from sieve 70 with survival rate of 19.52% and 14.72%, and 0.22% and 0.77%, respectively. Levan production was also determined from encapsulated cells providing the highest survivor rate which was beads from sieve 10 of 3 % sodium alginate. Results showed they that there was no significant difference (p > 0.05) in levan production between free cell and encapsulated cells from high temperature condition test.
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ItemEncapsulation of protease from Aspergillus oryzae and lipase from Thermomycess lanuginoseus using alginate and different copolymer type( 2016) Thu, Truong Thi Mong ; Wunwisa KrasaekooptAlthough the application of enzymes in food as a food processing aid and enzyme supplement is ofinterest and widely used, the enzymes can be easily deactivated or lose their activity due to many causessuch as pH and moisture as well as through the introduction of incompatible ingredients during foodprocessing and storage. These problems can be solved by the encapsulation technique, especially in a gelmatrix. The influences were studied of the alginate concentration, types of copolymer and their con-centrations on the bead size, encapsulation yield (EY), encapsulation efficiency (EE), leakage and theretention of enzyme activity during storage period of encapsulated protease from Aspergillus oryzae andlipase from Thermomyces lanuginosus beads. A solution of purified protease or lipase was encapsulated incalcium alginate-chitosan beads (CACB), calcium alginate-xanthan gum beads (CAXB) and calciumalginate-maltodextrin beads (CAMB) using the extrusion method. Increasing the alginate and copolymerconcentrations in the solution increased the bead size, EY, EE and the retention of enzyme activity duringthe storage period and reduced leakage of both the encapsulated protease and lipase. In addition,different types of copolymer significantly (p0.05) affected these properties of both encapsulatedenzymes. Furthermore, protease encapsulated using 2.0% alginate and 0.2% chitosan provided the highestEY (81.7%) and EE (77.2%) with a bead size of 1.85 mm and 8.1% leakage. The retention of encapsulatedprotease activity and the shelf-life of encapsulated enzyme which was expressed as half-life, the timerequired for the enzyme activity to decrease by half (thalf life) were 75.8% and 27.2 wk, respectively afterstorage at 4C for 10 wk. For lipase, encapsulation using 2.0% alginate and 0.4% xanthan gum providedthe highest EY (42.5%) and EE (43.9%) and the bead size and leakage were 1.81 mm and 6.2%, respectively.The retention of encapsulated lipase activity and the thalf lifewere 77.9% and 27.8 wk, respectively afterstorage at 4C for 10 wk. CACB was a suitable complex polymer for encapsulating protease while CAXBwas suitable for lipase. EY and EE values of CACB-protease were higher than those of CAXB-lipase.Therefore, the encapsulation method, gelling conditions and interactions between carriers and lipaseshould be further studied.
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ItemMicroencapsulation of Saffron (Crocus sativus L.) Extract in Copolymer Complexes Using Extrusion Method( 2015) Shakoori, Pooria ; Wunwisa KrasaekooptThis study describes the preparation of alginate-chitosan and alginate-gelatin beads containing saffron components to be incorporated as additives in food products. This study evaluated the influence of incorporating hydrophilic natural polymers, alginate-chitosan and alginate-gelatin on preserving saffron components. The alginate beads were coated with chitosan and gelatin as copolymer by extrusion method with a polyelectrolyte complex reaction between two oppositely charged poly-ions. The beads were formulated, optimized and evaluated to obtain high encapsulation efficiency of crocin, safranal and picrocrocin as the main components of saffron. The encapsulation variables were selected in accordance with Central Composite Design and were further optimized via response surface methodology. Alginate concentration significantly influenced particle size and encapsulation efficiency of alginate-chitosan and alginate-gelatin beads (p ≤ 0.05). Both chitosan and gelatin positively affected encapsulation efficiency. The optimum condition for preparing alginate-chitosan beads was an alginate concentration of 1.97% and chitosan concentration of 0.925%; this yielded an encapsulation efficiency of 66.3 ± 1.5, 86.2 ± 0.7 and 52.9 ± 3% for picrocrocin, safranal and crocin, respectively. The optimum condition for preparing alginate-gelatin beads was an alginate concentration of 1.95% and gelatin concentration of 3.65%; this yielded encapsulation efficiency of 39.2 ± 2.9, 31.9 ± 1.7 and 18.3 ± 1% for picrocrocin, safranal and crocin, respectively. The results clearly indicated that, in combination with alginate, chitosan was a better copolymer than gelatin for encapsulating saffron components.
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