19-08-2014, 11:46 AM
Natural pigments have fascinated researchers due to their ubiquitous occurrence, varied functions and consumer acceptance. Despite the availability of a variety of natural and synthetic carotenoids, only a few such as -carotene, lycopene and astaxanthin have been exploited commercially.
Natural pigments have fascinated researchers due to their ubiquitous occurrence, varied functions and consumer acceptance. Despite the availability of a variety of natural and synthetic carotenoids, only a few such as -carotene, lycopene and astaxanthin have been exploited commercially.
Lycopene is a red-coloured carotenoid that is also a potent antioxidant and anti-carcinogenic. It has attracted attention as a feed supplement and nutraceutical. Globally, the production of lycopene in 2004 was reported to be 15,000 tonnes and priced at 54 million dollars. Commercially, lycopene is extracted from tomatoes and its byproducts. Poor and variable yields have prompted to look for alternate sources, of which the most promising is fermentative production. This project was undertaken to explore fermentative production and downstream processing of lycopene.
The zygomycete fungus Blakeslea trispora is used commercially as natural source of -carotene. Initially, the wild strains as well as intraspecific mated B. trispora (+) and (-) were studied for maximizing the yield of -carotene. Media components and process variables for production of -carotene by the mated culture was optimized in shake flask levels by one factor at-a-time and subsequently by response surface methodology. In the biochemical pathway, lycopene is converted to b-carotene by the enzyme, lycopene cyclase. Hence, after successful attempts for maximum production of -carotene, use of inhibitors of lycopene cyclase for accumulation of lycopene was undertaken. Screening of possible inhibitors, its concentration and time of addition were established.
Scale-up studies to study the effect of varying dissolved oxygen (DO) and fluid shear rate on lycopene production and the morphology of mated cultures of B. trispora in an optimized medium using 5 litres Sartorious fermentor was carried out. Separation and purification of lycopene from microbial biomass by reverse phase chromatography was developed. Supercritical carbon dioxide extraction (solvent free) process was investigated to check the efficacy of lycopene extraction with the use of an entrainer. The effect of operating conditions on the extraction of lycopene from dried biomass was studied using Box-Behnken design.
Further studies were conducted on encapsulation of lycopene using individual, binary and ternary blends of gum arabic/maltodextrin /n-OSA modified starch. Finally, the use of encapsulated lycopene vis-à-vis free lycopene (with the wall materials developed in the study) as pre- extrusion colouring of rice flour was carried out. The approach developed in this study is simple, novel and can be exploited commercially.