Emulsion and Surface-Active Properties of Fish Solubles Based on Direct Extraction and after Hydrolysis of Atlantic Cod and Atlantic Salmon Backbones

Abstract

The focus on natural foods and “clean” labeled products is increasing and encourages development of new biobased ingredients. Fish solubles derived from downstream processing of side stream materials in the fish filleting industries have potential as emulsifiers based on their surface-active and emulsion stabilizing properties. The aim of this study was to evaluate and compare emulsion properties and critical micelle concentration (CMC) of direct protein extracts and protein hydrolysates based on fish backbones, and to identify associations between molecular weight distribution and process yield with the studied physicochemical properties. Protein extracts and enzymatic protein hydrolysates were produced based on two raw materials (cod and salmon backbones), two enzymes with different proteolytic specificity, and varying hydrolysis time. Emulsion activity index (EAI), emulsion stability index (ESI) and CMC were measured and compared with casein as a reference to protein-based emulsifiers. Protein hydrolysis was found to have negative impact on EAI and CMC, likely due to generation of small peptides disrupting the amphiphilic balance. The direct protein extracts had comparable EAI with casein, but the latter had superior ESI values. Protein hydrolysates with acceptable EAI could only be obtained at the expense of product yield. The study emphasizes the complexity of physicochemical properties of protein hydrolysates and discusses the challenges of achieving both good surface-active properties and high product yield.

Steam Explosion-Assisted Extraction of Protein from Fish Backbones and Effect of Enzymatic Hydrolysis on the Extracts

“…Particularly, fish bones are good sources of protein and bio-calcium [3]. After appropriate processing, these raw materials may find potential applications among a series of food products [4][5][6][7].…”

Influence of mixing speed, solids concentration and enzyme dosage on dry solids yield and protein recovery during enzymatic hydrolysis of sardine (Sardina pilchardus) processing by-products using Alcalase 2.4L: a multivariable optimisation approach

“…The statistical interaction between mixing speed and solids concentration can be explained by the fact that emulsion formation requires mechanical energy to be supplied to the system [62]. Furthermore, previous research has shown that hydrolysed proteins have high emulsion activity (the maximum interfacial area per unit mass of protein in a stabilised solution), emulsion capacity (the maximum amount of oil that can be emulsified under specified conditions by a unit mass of protein) and emulsion stability (the capacity of a protein to form an emulsion that remains unchanged for a certain time period at a given temperature and gravitational field) [41,57,[63][64][65][66]. These physicochemical properties also explain the effect of solids concentration and enzyme dosage.…”

Optimization Technology of Fat-Soluble Vitamins Production Based on Alkaline Hydrolysis

“…Учитывая, что основным источником получения жирорастворимых витаминов является печень рыб, то стоит вопрос о создании соответствующей технологии с акцентами на вопросы бережливого производства (минимизацию отходов с максимальным ресурсосбережением ценного сырьевого источника) [17,18].…”