15D-24 |
Hydrolysis of caroproteins from shrimp wastes using an enzymatic membrane bioreactor |
I. GUERRERO LEGARRETA, Departament of Biotechnology, Universidad Autonoma Metropolitana, Iztapalapa Campus, Av. Michoacan y Purisima s/n, Mexico D.F., 09340, Mexico, R. E. Armenta, Department of Biotechnology, Universidad Autonoma Metropolitana, Iztapalapa Campus, Av. Michoacan y Purisima s/n, Mexico D.F., 09340, Mexico, and M. N. de Pinho, Instituto Superior Tecnico, Universidade de Tecnologia de Lisboa, Av. Rovisco Pais 1, Lisbon, Portugal. Astaxanthin is widely used in salmon and trout diets for flesh pigmentation and, more recently, as a natural ingredient to cosmetics and foods. Salmonids, like other animals do not synthesize carotenoids de novo. Therefore to pigment their flesh, hence to increase the quality and acceptance by the consumer, it is necessary to include the pigment in the formulation. In the wild, fish obtain these carotenoids by consuming crustacean where astaxanthin is bound to high-density lipoproteins forming complexes known as caroproteins. The main by-products of Mexico's shrimp production are shells and heads, which in turn present a serious pollution problem in the catching and farming areas. The objective of this work was to study astaxanthin extraction from shrimp wastes applying an enzymatic hydrolysis of the caroprotein complex in an enzymatic bioreactor. Shrimp wastes were subject to lactic ensilation which stabilized the pigment. The resulting liquor was treated with 15 or 20 proteolytic units of a commercial protease during 16 hours. Polysulphone membranes with a range of nominal molecular weight cut-off (MWCO) were tested in a subsequent ultrafiltration process. The most efficient enzymatic treatment, in terms of splitting the protein from the pigment, required 20 proteolytic units at pH 8 and 40°C (P>0.0001). Ninety eight percent of the soluble protein was obtained using a 10 kDa MWCO polysulphone membrane. Protein and highly valuable astaxanthin from the caroprotein complex in crustacean wastes can be recovered using an enzymatic membrane bioreactor followed by ultrafiltration to separate the two moieties. The protein-free pigment has an increasing market in the fish farming and food industries. The protein has a potential use as attractant in the fish farming industry.
Session 15D, Food Engineering: Processing Technologies
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