| Summary: | 碩士 === 國立臺灣海洋大學 === 食品科學系 === 104 === Astaxanthin is a strong anti-oxidant, but it becomes unstable in light, high temperature and high oxygen partial pressure. It oxidize easily and loses anti-oxidant capacity. In this study, 0.07 g/mL β-cyclodextrin and maltodextrin were used as the coating material, and lecithin as the emulsifier to microcapsulate 0.07 g/mL of astaxanthinat the rate of 4: 1 (v/v).Micro-encapsulated powders after spray-drying and freeze-drying were divided into four groups: spray-dried-β-cyclodextrin (SC), spray-dried-maltodextrin (SM), freeze-dried-β-cyclodextrin (FC), freeze-dried - maltodextrin (FM).Spray-dried samples had better encapsulation efficiency (EE), where as SC with 2% lecithin had the best EE rate of 89.94%. In the particle size analysis,the powder particles formed by spray drying are smaller and have smaller particle size distribution, while the freeze-dried particles are larger and have larger particle size distribution. The diameter of the SC, SM, FC and FM are 224.9 ± 9.9nm, 472± 33nm, and 624± 194nm, 887± 110nmrespectively. All groups have good preservation with water activity between 0.2 and 0.5. Chromatographic analysis indicated that β-cyclodextrin coating group L * value is higher, and maltodextrin coating group L * value is low. This represents a lighter color of the particles can be obtained by coating with β-cyclodextrin. In the storage test, samples were stored at -40 ℃, 4 ℃, room temperature (21.7℃), 40 ℃ and darkroom, 300 lux and 1500 lux for 30 days. Under room temperature darkroom, the antioxidant capacity of bare astaxanthin (BA) decreased rapidly from 4th day, while the encapsulated groups decreased from 8th day. Furthermore, the content of astaxanthin was higher. It is clear that coating with dextrin can effectively extend the antioxidant capacity of astaxanthin. In temperature control storage test, SM has the best temperature stability. It’s antioxidant capacity continue to decline until the 10th day and the amount of astaxanthin in the storage after 30 days still has 68.68 ± 2.41%. Light stability can be seen in the FM. Light will significantly accelerate the decrease in antioxidant capacity of the sample and reduce the content of astaxanthin. But in the 300 lux of room temperature, SM has the best light stability and the amount of astaxanthin in the storage after 30 days still has 80.67±3.29%. In the simulated gastrointestinal digestion test, the concentration of astaxanthin in the group coated by spray drying was a stable decrease. In addition, the concentration of astaxanthin were coated by β-cyclodextrin will begin to decline rapidly after 90 minutes. But maltodextrin coated groups will have a more stable period. That means microcapsulation with maltodextrin by spray drying has good stability in simulated gastric juice and intestinal fluid. In controlled release test, the increase in the release rate of the maltodextrin group was slower. That means maltodaxtrin can provide a better control and release capacity in the simulatedgastric juice and intestinal fluid. Using dextrin to microencapsulate astaxanthin can effectively enhance the storage stability and has high stability in simulated gastric juice and intestinal fluid.
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