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Chlorella vulgaris is known for its protein, growth factor, and nutritional constituents. Chlorella vulgaris was cultivated in a 1000-L outdoor open raceway pond with a maximum volumetric productivity of 130 mg L-1 day-1. The harvested biomass was dried through different methods, viz., sun drying (30 °C), oven drying (60 °C), lyophilization (−110 °C), drum drying (120 °C), and spray drying (100–150 °C). The effect of the drying method on proximate composition, pigments (chlorophyll, carotenoids), bioactive compounds (total phenolic content, flavonoid content), vitamin B12, antioxidant properties (ferric reducing antioxidant power, DPPH, and total antioxidant activity), and the color quality of C. vulgaris biomass was evaluated. Surface characterization by scanning electron microscopy (SEM) and functional group characterization through Fourier transform infrared spectroscopy were also performed. The biomass dried through lyophilization and sun drying retained maximum bioactive compounds and antioxidant activities. In contrast, drum drying resulted in a loss of nutrients, viz., protein (up to 44%), lipid (up to 41%), vitamin B12 (up to 40%), total phenolic content (> 50%), total flavonoid content (> 50%), and antioxidant activity (> 50%). Oven drying led to a loss of 30% in total flavonoid content and 17% in ferric reducing antioxidant power. SEM showed the destruction of cell wall integrity in the drum-dried sample and porous structure in the spray-dried sample. This study suggests that drying methods affect the nutrients and bioactive compounds of C. vulgaris biomass, and therefore a drying method should be selected carefully depending on the end use of the biomass. [ABSTRACT FROM AUTHOR]

The current demand for edible vegetable oil is increasing worldwide, and the development of new sources of high-quality vegetable edible oil is an essential task. There is also a huge demand for biodiesel in domestic and industrial applications, and foliage oils could be a good source for diesel applications. The current study aimed at the identification and quantification of fatty acids from commonly consumed green leafy vegetables (GLVs) viz., Hibiscus cannabinus, Hibiscus sabdariffa, Basella alba, Basella rubra, and Rumex vesicarius and to calculate the biodiesel attributes of the oil. The total oil content was ascertained as the highest in R. vesicarius foliage (3.91 ± 0.27 g/100 g dry leaf powder). GC/MS chromatographic investigation identified 9,12,15-octadecatrienoic acid as a significant compound followed by hexadecanoic acid. In Hibiscus spp. C18:3 (49.3 µmol % and 50.4 µmol %) was recorded to be the most noteworthy followed by C16:0 (23.2 µmol % and 21 µmol %) in H. cannabinus and H. sabdariffa, respectively. The GLVs foliage-fatty acid biodiesel attributes were additionally assessed through an empirical formula. Consequently, the overall examined results will be helpful for the investigation of these oils as vegetable oil for human consumption and biodiesel applications. [ABSTRACT FROM AUTHOR]