Mexican grasshopper (Sphenarium purpurascens) as source of high protein flour: Techno-functional characterization, and in silico and in vitro biological potential.

The aim of this work was to evaluate the techno-functional properties of Mexican grasshopper flour with different thermal pretreatments, as well as to assess the anti-inflammatory and antioxidant potential of their protein hydrolysates. Insect flour was thermally treated at 70, 80, 90, and 121 °C. Insect flour protein solubility (184.3 - 278.5 mg/g) was higher at pH 7.0 - 11.0. Thermally processed flour at 70, 80 and 90 °C showed no significant differences (p > 0.05) in water/oil holding capacity, emulsion properties and gel minimum concentration. Protein hydrolysates presented antioxidant potential for DPPH (IC50: 0.78 mg/mL), ABTS (IC50: 0.63 mg/mL) and nitric oxide (IC50: 2.21 mg/mL). Protein hydrolysates showed inhibition potential against enzymes COX-2 (IC50: 0.52 mg/mL) and iNOS (IC50: 0.51 mg/mL) in biochemical trials. Molecular docking showed that from the 37 identified peptide sequences, GPPGPAGV (-9.5 kcal/mol) and KPTVGVVTY (-10.4 kcal/mol) have the lower binding energies for COX-2 and iNOS, respectively. S. purpurascens flour and protein hydrolysates could be used as a functional ingredient.

Isolation and identification of proteolytic lactic-acid bacteria of the common carp (Cyprinus carpio) by spontaneous fermentation to obtain functional peptides.

High proteolytic activity and several biological functions (antimicrobial, antioxidant, antihypertensive, among others) have been attributed to lactic-acid bacteria (LAB) isolated from fish and peptides obtained from proteolysis. Therefore, the objective of this research was isolating, characterizing, and identifying LAB with proteolytic activity by spontaneous fermentation from common carp (Cyprinus carpio) reared in ponds and wild ones obtained from Lago de Chapala, Jalisco, Mexico. Spontaneous fermentation from complete carp specimens was observed, considering two sampling points (skin and intestines) at 15 °C at 5 and 10 days. Isolated LAB-from both reared and wild specimens-were identified and morphologically characterized; identification was performed by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS). Proteolytic activity was assessed by the presence of the proteolytic halo. A total of five genera and eight different LAB proteolytic species were isolated from all the carp samples. At 10 days, greater proteolytic LAB diversity was obtained from the intestine (Tukey's, p < 0.05); the proteolytic halo with the greatest diameter was recorded in wild carp skin with Lactiplantibacillus plantarum S5P2 (2.8 cm) at 5 days of fermentation, followed by Leuconostoc mesenteroides S5I1 (2.73 cm) and Leuconostoc pseudomesenteroides S5P2 (2.66 cm) (p < 0.05). In conclusion, proteolytic capability of LAB isolated from carp (Cyprimus carpio)-both wild and reared-is influenced by the ecosystem where they develop. These proteolytic LAB may be used in biotechnological industries to obtain bioactive peptides by fermenting substrates rich in proteins.