Solubility consideration in extraction of astaxanthin from Haematococcus pluvialis using supercritical carbon dioxide

Abstract

Calcium lactate, is a nontoxic water-soluble food additive for making bread, soy milk, orange juice and yogurt. Calcium lactate is also reported to function as an anti-microbial, enhancer of bone mineral density, anti-caries, anti-carcinogen (1, 2). This paper is concernedwith optimization of effect factors for nano calcium lactate crystal production by chemical precipitation by onefactor-at-a-time and orthogonal methods. The one-factor-at-a-time method was adopted to investigate the effects of L-lactic acid concentration, operating temperature, the ration of calcium hydroxide to lactic acid, stirring speed on the purity, the mean size, the output and crystal morphology of calcium lactate particle was determined. Among these factors, L-lactic acid concentration, stirring speed, temperature and the amount of ethanol were identified to be the most important factors. Subsequently, these factors were optimized using the orthogonal matrix method. The optimal conditions were determined as 6mol/l L-lactic acid , 500 rpm, 50 °C and 50% ethanol (v/v). The subsequent verification experiments confirmed the validity of the models. Under this optimized conditions, the particle size of calcium lactate, the yield and the purity were 55 nm, 85% and 98%, respectively.