Revalorization of crustacean by-products, chemical applications and academic computing packages. Part 2. Theoretical-practical applications with shrimp waste, astaxanthins

Abstract

In this theoretical-practical research, one of the most abundant byproducts of the fishing industry was evaluated, the cephalothorax and exoskeletons of shrimp, whose composition is: 44.7% nitrogen (protein and non-protein), 26.3% ash, 20.7% crude fiber (which includes to the biopolymer chitin), 5.2% fat and 3.1% other carbohydrates. The components of greatest interest were separated: Pigments and protein and chitin through unit operations, which were: Washing, grinding, filtration, and decantation developed in different laboratory-scale investigations. The main objective of this phase of the research was aimed at taking advantage of one of these byproducts: Carotenoproteins. During the processing of the shrimp exoskeletons and cephalothorax, an aqueous extract was obtained during washing and grinding, leaving the carotene-proteins dissolved and/or emulsified in it. To extract them, commercial fish oil was used and, among the results obtained on a laboratory scale, the carotenoid pigments were obtained, which, measured as astaxanthin, were 18.4±0.1 μg/mL fish oil using a 2:1 ratio (water from grinding-washing: fish oil). Using the academic computing packages available at the Faculty of Chemistry on the equipment also provided by UNAM, a theoretical evaluation was made considering 500 kg h-1 of byproducts for 360 d per year as a calculation basis. The sizing of the process on an industrial scale using the Aspen Plus® software allowed us to obtain the amount of the investment considering the equipment used, which was $10,895,540.00 USD (US dollars). If fish oil pigmented with carotene-proteins were sold for penaeid diets or for nutraceutical uses, $3,734,531.60 USD/year would be obtained. This amount indicates that the capital investment would be recovered in 2.9 years, making the process economically viable. This technical-economic feasibility study carried out using computing packages such as ASPEN PLUS allowed us to verify the goodness of this basic research on a laboratory scale.