Claire Donnay-Moreno

Enzymatic hydrolysis of cuttlefish (Sepia officinalis) and sardine (Sardina pilchardus) viscera using commercial proteases: effects on lipid distribution and amino acid composition.

Total lipid and phospholipid recovery as well as amino acid quality and composition from cuttlefish (Sepia officinalis) and sardine (Sardina pilchardus) were compared. Enzymatic hydrolyses were performed using the three proteases Protamex, Alcalase, and Flavourzyme by the pH-stat method (24 h, pH 8, 50 degrees C). Three fractions were generated: an insoluble sludge, a soluble aqueous phase, and an oily phase. For each fraction, lipids, phospholipids, and proteins were quantified. Quantitative and qualitative analyses of the raw material and hydrolysates were performed. The degree of hydrolysis (DH) for cuttlefish viscera was 3.2% using Protamex, 6.8% using Flavourzyme, and 7% using Alcalase. DH for sardine viscera was 1.9% (using Flavourzyme), 3.1% (using Protamex) and 3.3% (using Alcalase). Dry matter yields of all hydrolysis reactions increased in the aqueous phases. Protein recovery following hydrolysis ranged from 57.2% to 64.3% for cuttlefish and 57.4% to 61.2% for sardine. Tissue disruption following protease treatment increased lipid extractability, leading to higher total lipid content after hydrolysis. At least 80% of the lipids quantified in the raw material were distributed in the liquid phases for both substrates. The hydrolysed lipids were richer in phospholipids than in the lipids extracted by classical chemical extraction, especially after Flavourzyme hydrolysis for cuttlefish and Alcalase hydrolysis for sardine. The total amino acid content differed according to the substrate and the enzyme used. However, regardless of the raw material or the protease used, hydrolysis increased the level of essential amino acids in the hydrolysates, thereby increasing their potential nutritional value for feed products.

Proteolysis of shrimp by-products (Peaneus monodon) from Madagascar Proteólisis de derivados de langostino (Peaneus monodon) de Madagascar

To generate and recover elements from shrimp heads, proteolysis was performed with commercial acidic or alkaline proteases for 22 h. The resulting phases were characterized for protein and lipid content and amino acid composition while the molecular profiles of soluble peptides were established. Whatever the protease used, more than the half of the initial dry matter was found into aqueous phase including most of the proteins while lipids were found to remain insoluble. Hydrolysates were mainly constituted by small peptides (>80% below 1000 Da) with up to 14–15 amino acids identified. Moreover, all the hydrolyses have led to an increase of the amount of essential amino acids into the hydrolysates, including lysine. Thus, such proteolysis of shrimp heads can increase their potential nutritional value (small peptides with high content in essential amino acids) while allowing the concentration of lipids into insoluble phase and a partial demineralisation of the exoskeleton. Para crear y recuperar elementos de las cabezas de langostino se llevó a cabo una proteólisis con proteasas ácidas y alcalinas comerciales durante 22 horas. Las fases resultantes se caracterizaron por contenido proteico y lípidico, composición de aminoácidos, mientras los perfiles moleculares de péptidos solubles fueron establecidos. Cualquiera fuese la proteólisis, más de la mitad de la materia seca inicial se encontró en fase acuosa, incluida la mayor parte de las proteínas, mientras los lípidos resultaron mantenerse insolubles. Los hidrolizatos estuvieron constituidos principalmente por pequeños péptidos (>80% por debajo 1000 Da) con hasta 14–15 aminoácidos identificados. Es más, todas las hidrólisis llevaron a un incremento de la cantidad de aminoácidos esenciales en los hidrolizatos, incluido lisina. Así, dicha proteólisis de cabezas de langostino puede incrementar de este modo su valor nutricional potencial (pequeños péptidos con un alto contenido en aminoácidos esenciales) mientras permite la concentración de lípidos en pase soluble y una desmineralización parcial de esqueleto externo.