Nutritive Values of Protein Hydrolysate Products from Shrimp Waste Utilization by Fermentation with Lactobacillus plantarum

Abstract

Abstract Shrimp hydrolysate proteins are produced from inedible parts of shrimp, such as the head, shell and tail, called GSW (ground shrimp waste). By fermentations with a proteolytic Lactobacillus plantarum strain 541, the inoculants were cultivated with commercial MRS (De Man, Rogosa and Sharpe) broth and pineapple juice broth (PA). There were four fermentation treatments: raw GSW fermented with inborn microorganisms, sterilized GSW fermented with MRS inoculant, raw GSW fermented with MRS inoculant, and raw GSW fermented with PA inoculant. The protein hydrolysate products of those treatments were compared with those of a nonfermented GSW and a commercial fishmeal, CFM. The changes in pH and viable cell number density concentrations (VSNC) or viable cell counts (CFU/g) were studied during fermentations at 0, 4, 8, 12, and 16 h. The pH values were controlled to 5.0–5.5 within the first 4 h. The hydrolysate protein products contained 48.6–52.5% (w/w) proteins, 5.4–8.0% (w/w) total lipids, 0.4–0.7% (w/w) fiber, and 12.0–13.5% (w/w) ash. The protein content in raw GSW fermented with MRS inoculant was the highest (p ≤ 0.05), close to the values of 55.6 and 63% (w/w) in nonfermented GSW and CFM. Moreover, the sixteen types of total amino acids of those hydrolysate protein products, nonfermented GSW and CFM presented high values. For this reason, the shrimp hydrolysate protein products here contain large amounts of amino acids, similar to those of the high-quantity protein source CFM. Thus, protein products from the hydrolysis of GSW by fermentation can replace CFM for animal feed protein sources. The in vitro results also showed that the shrimp hydrolysate proteins contained highly digestible proteins. They also presented varying molecular weights of 26–77 kDa of short peptides on SDS-PAGE.