Topical Area: Dietary Bioactive Components
Invasive green crabs (Carcinus maenas) have become well established in the U.S. over the past 100 years. Despite containing nutritionally important proteins, unsaturated fatty acids, and minerals, green crabs are not consumed due to their small size. A variety of peptides derived from muscle foods are known to have health benefits, and we hypothesized that high quality green crab proteins and their derivatives might have potential as carbohydrase inhibitors. Therefore, the primary objective of this study was to obtain anti-hyperglycemic peptides via enzymatic hydrolysis to develop commercial value of this unutilized crustacean.
Methods : Mechanically separated crab meat was homogenized with water (1:1), then hydrolyzed with 1% of Alcalase (AL, pH 8), Protamex (PR, pH 7), Flavourzyme (FL, pH 7), or Papain (PA, pH 6) for 60 min. Enzymes were thermally inactivated and then the hydrolysates were centrifuged to obtain the supernatant, then freeze-dried. Samples were processed in triplicate and then evaluated for degree of hydrolysis (DH) and α-glucosidase and α-amylase inhibitory activities . Significant (p< 0.05) differences in DH and carbohydrase inhibitory activities among treatments were determined by one-way ANOVA.
Crab mince treated with AL exhibited the highest DH (18.3%), followed by PR (17.1%), FL (16.5%), and PA (15.8%). The PR treatment showed the highest α-glucosidase inhibitory activity (IC50 3.6 mg/mL) compared to other enzyme treatments (IC50 19.3-46.3 mg/mL) and the Control (IC50 22.3 mg/mL). The α-amylase inhibitory activity of PR (IC50 24.4 mg/mL) was lower than its α-glucosidase inhibitory activity. FL showed the highest α-amylase inhibitory activity (IC50 23.5 mg/mL) followed by PR, PA (IC50 34.8 mg/mL), AL ( IC50 35.4 mg/mL), and Control (IC50 36.5 mg/mL) samples.
Conclusions : Our findings indicate that Protamex treatment has potential to derive carbohydrase inhibitory peptides from green crab and these peptides could be utilized as a health promoting ingredient in food products. In order to investigate changes in bioactivity due to human digestion, the hydrolysates will be utilized in a simulated digestion model and their bioactivity will be further evaluated.
Funding Sources : This study is supported by a National Science Foundation grant to Maine EPSCoR at the University of Maine.