Voranuch Suvanich and Michael Moody
Louisiana has the nation’s most productive commercial shrimp fishery, landing about 100 million pounds a year with a dockside value of $150 million. White and brown shrimp make up most of Louisiana’s harvest. Pink shrimp and sea bobs (small brownish shrimp, more than 100 per pound, with many antennae and a long curved and spiny head) are also caught and sold, but in much smaller quantities.
Although fresh, frozen and canned shrimp dominate the market, there is still a demand for dried shrimp. Dried shrimp is an intermediate moisture and shelf-stable product normally used as a snack or as a food ingredient and flavor enhancer in Asia, Africa, South and Central America, and in the United States, especially Louisiana, California and Hawaii. Dried shrimp are categorized by processing types into freeze-dried and sun-dried shrimp. Freeze-dried shrimp are normally sold as fish food, and sun-dried shrimp are for human consumtpion.
The shrimp drying process, using hot-air indoor dryers, is energy and time consuming and normally takes five to eight hours for dried shrimp to reach an internal water activity required for product shelf-life stability and safety. Additionally, the product may not have a uniform moisture content, which may result in poor quality and short shelf-storage life. After shelling, low-value byproducts consisting of small pieces of separated heads and shells are generally sold as byproducts.
According to our studies, drying times and temperatures and ratios of surface air/above air and drier air temperatures could be used to indirectly monitor critical limits if processors could control: (1) uniform shrimp size, (2) shrimp weight per dryer bin, (3) dryer bin size (length, width and depth), and (4) forced air temperatures and air flow rates of dryers. Finally, we evaluated changes in visual appearance and sensory characteristics of sampled shrimps during drying. Our research provides guidance on how science-based principles can be practically applied and implemented not only in Louisiana’s small and less developed dried shrimp businesses but also worldwide.
Although dried shrimp has a limited market and is produced in smaller amounts than frozen shrimp products, dried shrimp processing is still a viable industry for the preservation of shrimp products in South Louisiana and represents a viable and traditional Louisiana shrimp product. Dried shrimp is still another source of revenue for Louisiana shrimp processors. The development of an effective drying process, which maintains short drying time with less energy consumption, would be economical and beneficial to producers. Moreover, the feasibility of protein recovery from boiled shrimp water and the use of dried heads and shells as a source of high quality protein, calcium and minerals for value-added human foods would make Louisiana dried shrimp processing even more cost effective.
Voranuch Suvanich, former Postdoctoral Student, and Michael Moody, Professor and Head, Department of Food Science, LSU AgCenter, Baton Rouge, La.
(This article was published in the fall 2002 issue of Louisiana Agriculture.)