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: A new carotenoid-rich product was formed by entrapment of Dunaliella salina in calcium alginate beads of di †erent alginate concentrations, followed by drying in a Ñuid-bed dryer. The drying process yielded b-carotene recoveries of between 79 and 89% and produced a change in the 9-cis/all-trans ratio of b-carotene isomers. The carotenoid stability of the product was dependant on both the storage conditions and alginate content (range 3É3È7É3 g litre~1) of the beads. In the presence of light and oxygen total carotenoid degraded following a Ðrst order kinetic model with degradation constants between 0É016 and 0É039 days~1, with the lowest degradation occurring with the lowest alginate concentration. Product stored in the dark and Ñushed with nitrogen produced Ðrst-order degradation constants of 0É012 and 0É020 days~1 for the two higher alginate concentrations ; that with the lowest alginate content showed no noticeable degradation after 58 days storage. During storage, the 9-cis isomer was signiÐcantly more unstable showing a relative loss under all conditions, degrading almost completely when stored in the presence of light and oxygen and reaching an equilibrium ratio with the all-trans isomer when stored in the dark and Ñushed with nitrogen.1998 SCI. ( Sci Food Agric 76, 298È302 (1998) J

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Low indoor air quality is an increasingly important problem due to the spread of urbanization. Because people spend most of their time inside, poor indoor air quality causes serious human health issues, resulting in significant economic losses. In this work, the current state of affairs is presented and analyzed, focusing on the current problems and the available solutions to improve the quality of indoor air, and the use of nature-based solutions. These involve the cultivation of microalgae in closed photobioreactors. In these systems, photosynthetic organisms can capture CO2 and other pollutants generated in indoor environments, which they use to grow and develop biomass. Several possible layouts for the implementation of microalgae-based indoor air cleaning systems are presented, taking into account the systems that are currently available at a commercial scale. A critical analysis of the microalgae indoor purification systems is presented, highlighting their advantages and disadvantages, and suggesting potential improvements and future lines of research and development in the area.