Antioxidant and Antimicrobial Enhancement by Reaction of Protein Hydrolysates Derived from Shrimp By-Products with Glucosamine

Abstract

Shrimp cooking juice and shrimp carapaces are interesting sources of protein which are habitually disposed of at large quantities by crustacean industries. In this work, protein obtained from the cooking juice and carapaces of Pacific white shrimp (Litopenaeus vannamei) was hydrolyzed by an enzyme extract of Enterococcus faecalis DM19 isolated from raw camel milk. The hydrolysates were afterwards heated separately with glucosamine (GlcN) at 100 °C for 0, 40, 60,120 and 180 min. The reaction was followed by measuring the change in absorbance at 294 and 420 nm and also by fluorescence (λexc = 340 nm; λem = 440 nm). Browning and intermediate products increased with heating time showing a concomitant decrease in free amino groups, while the pH decreased as well. Amino acid analysis showed that the amounts of lysine, arginine, and histidine decreased significantly after heating for 180 min. The infrared spectra suggested the appearance of new molecules after heating, presumably Schiff bases and/or aromatic compounds. The antioxidant and antimicrobial activities of the heated hydrolysates were compared to those of the native hydrolysates. Interestingly, the reducing ferric ion activity was improved 22-fold after conjugation. Meanwhile, both scavenging radical and metal chelating ion activities were increased sevenfold. Besides, the shrimp carapace hydrolysate heated in presence of GlcN exhibited a good antibacterial activity against gram positive and gram negative bacteria. To conclude, protein hydrolysates derived from the shrimp by-products studied in this work could be heated in presence of GlcN at 100 °C and be potentially used as antioxidant and/or antibacterial ingredients for different purposes.

Optimization of fish gelatin drying processes and characterization of its properties

“…However, its processing generates a large amount of waste, such as head, tail, scales, fins, swimming bladder, cartilage, guts, and skin 2 , 3 . These residues are usually discarded directly into the environment causing contamination problems, despite these residues contain proteins and are rich in essential amino acids 4 . Specifically, the acoupa weakfish skin removed during processing is rich in protein and collagen, which can be used for gelatin extraction, while adding value and reducing the environmental pollution.…”

Hydrolysis of Shrimp Cooking Juice Waste for the Production of Antioxidant Peptides and Proteases by Enterococcus faecalis DM19

“…A measure of the reducing power of samples was performed as described previously [15]. Shortly, 30 µL of sample (25 mg/mL) were incubated with 90 µL of Milli-Q water and 900 µL of FRAP reagent, containing 10 mM of TPTZ and 20 mM of FeCl3 at 37 °C during 30 min.…”

Utilization of marine by-products for the recovery of value-added products

“…The increasing demand for protein on a global scale turns the focus on underutilized protein sources (Rustad, 2003;Shahidi and Rahman 2018). Fish processing typically results in a large percentage of by-products, much of which is high in nutritionally desirable muscle protein (Djellouli et al, 2019;Le Gouic et al, 2019, Ockerman, 1992. These protein-rich by-products include cut-offs, backbones, heads, skin, milt, stomach, viscera, and blood, among oth-ers.…”

“…These protein-rich by-products include cut-offs, backbones, heads, skin, milt, stomach, viscera, and blood, among oth-ers. For example, shrimp processing industry is producing higher amounts of by-products including carapaces, heads, and tails that account for up to 20-50% of total weight (Djellouli et al, 2019) and most of these discards are rich in different bioactive compounds. In general, fish meat and oil left on the by-products range widely, but typically account for 20-30 g/100 g and 5-15 g/100 g, respectively .…”