Optimal Production of Protein Hydrolysates from Monkfish By-Products: Chemical Features and Associated Biological Activities

Abstract

The aim of this work was the recovery of protein substrates from monkfish waste (heads and viscera) generated in the on-board processing of this species. Initially, the effect of pH, temperature, and protease concentration was studied on mixtures of a 1:1 ratio (w/v) of monkfish heads/water. The optimal conditions of proteolytic digestion were established at 57.4 °C, pH 8.31, [Alcalase] = 0.05% (v/w) for 3 h of hydrolysis. Later on, a set of hydrolysis at 5L-pH-stat reactor were run under the aforementioned conditions, confirming the validity of the optimization studies for the head and viscera of monkfish. Regarding the chemical properties of the fish protein hydrolysates (FPH), the yield of digestion was higher than 90% in both cases and the degrees of hydrolysis and the soluble protein content were not especially large (<20% and <45 g/L, respectively). In vitro digestibility was higher than 90% and the percentage of essential amino acids ranged from 40 to 42%. Antioxidant activities were higher in viscera FPH, and antihypertensive ability was superior in head FPH. The values of number average molecular weights (Mn) of monkfish hydrolysates were 600 Da in the viscera and 947 Da in the head. The peptide size distribution, obtained by size-exclusion chromatography, indicated that the largest presence of peptides below 1000 Da and 200 Da was observed in the viscera FPH.

Production and Physicochemical Characterization of Gelatin and Collagen Hydrolysates from Turbot Skin Waste Generated by Aquaculture Activities

“…Digestibility and antihypertensive activity ( Table 4 ) appear correlated with the Mw of the hydrolysates, with more fragmented protein possessing higher digestibility and antihypertensive activity. However, previous studies have reported contradictory results, finding direct [ 45 ], inverse [ 46 ], or no relationship [ 29 , 47 ].…”

“…Digestibility and antihypertensive activity (Table 4) appear correlated with the Mw of the hydrolysates, with more fragmented protein possessing higher digestibility and antihypertensive activity. However, previous studies have reported contradictory results, finding direct [45], inverse [46], or no relationship [29,47]. Digestibility and antihypertensive activity (Table 4) appear correlated with the Mw of the hydrolysates, with more fragmented protein possessing higher digestibility and antihypertensive activity.…”

Characterization of Gelatin and Hydrolysates from Valorization of Farmed Salmon Skin By-Products

“…Digestibility and antihypertensive activity ( Table 7 ) appear correlated with the M w of the hydrolysates, with more fragmented protein possessing higher digestibility and antihypertensive activity. However, previous studies have reported contradictory results, finding direct [ 47 ], inverse [ 48 ], or no relationship [ 20 , 32 ].…”

Exploiting of Secondary Raw Materials from Fish Processing Industry as a Source of Bioactive Peptide-Rich Protein Hydrolysates

“…Sea bream Fish Scales [28] Alaska pollack (Theragra chalcogramma) Frame [29] Hoki (Johnius belengerii) Frame [30] Catla catla Visceral organs [31] Sturgeon Visceral organs [32] Tuna Liver by-products [33] Alaska pollock Frames/backbones [34] Skate Skin [35] Cod (Gadus macrocephalus) Skin [36] Channa striatus Roe [37] Bluefin tuna Head [38] Salmon Pectoral fin [39] Seabass Skin [40] Leatherjacket Head waste [41] Japanese threadfin bream Frame waste [42] Rainbow trout By-products [43] Squid By-products [44] Leiognathus splendens By-catch [45] Salmon By-products [46] Monkfish By-products like head and viscera [47] Turbot By-products [48] Fish Solid and liquid waste generated from processing operations [49]…”