Purification procedures to obtain light-harvesting complexes were performed on two photosynthetic bacteria, i.e. Rhodospseudomonas (Rps.) palustris and Rhodobacter (Rb.) sphaeroides. In this study, purification was initially carried out using series of centrifugation towards the bacteria cell to acquire chromatophore of the bacteria. Application of detergent (lauryldimethylamine oxide, or LDAO) to the chromatophore enabled the extraction of membrane containing photosynthetic apparatus. Further purification involved the application of sucrose density gradient centrifugation and ion exchange chromatography. The purity of collected LH2 complexes can be determined by calculating the ratio of AB850 : Aprotein. The resulting LH2 complexes from both bacteria showed relatively high ratio suggesting the purity of the complexes.
Marigold (Tagetes erecta L.) flower is a potential source of lutein and zeaxanthin. The drying treatment of marigold flower is necessary during the industrial process for the preparation of these carotenoids. However, drying treatments with high temperature led the carotenoids undergo the isomerization reaction. Therefore, the aims of this study are to examine the effect of several drying treatments on lutein and zeaxantin contents, and to characterize a versatility of encapsulated lutein ester powder. Separations of the pigments were performed by highperformance liquid chromatography (HPLC) equipped with photodiode array detector on a C30 column. All-trans isomer of lutein was identified as the major carotenoid of two different marigold cultivars, i.e. Mega Gold (MG) and Mega Orange (MO). The contents of all-trans isomers of lutein and zeaxanthin were 8.95 − 14.55 mg/g dry weight (dw) in MO and 2.56 - 3.73 mg/g dw in MG. The best drying treatment to maintain carotenoid content was freeze drying, while the treatment with oven at 100°C decreased in carotenoids content up to 38%. The encapsulated lutein esters by spray drying and freeze drying showed microparticle size with the different morphological shapes. The encapsulated powders by spray drying produced uniform particles with sperical shape and smooth as well as concave surfaces, while the broken glass of encapsulated powders was obtained by freeze drying. MO cultivar of marigold appears to be a potential source of lutein and zeaxanthin. Encapsulation process may increase in the solubility of carotenoids and widen its application in food or nutraceutical products.
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