Influence of degree of hydrolysis on functional properties and angiotensin I-converting enzyme-inhibitory activity of protein hydrolysates from cuttlefish (Sepia officinalis) by-products.
BACKGROUND
In Tunisia the cuttlefish-processing industry generates large amounts of solid wastes. These wastes, which may represent 35% of the original material and constitute an important source of proteins, are discarded without any attempt at recovery. This paper describes some functional properties and the angiotensin I-converting enzyme (ACE)-inhibitory activity of protein hydrolysates prepared by hydrolysis of cuttlefish (Sepia officinalis) by-products with crude enzyme extract from Bacillus licheniformis NH1.


RESULTS
Cuttlefish by-product protein hydrolysates (CPHs) with different degrees of hydrolysis (DH 5, 10 and 13.5%) were prepared. All CPHs contained 750-790 g kg(-1) proteins. Solubility, emulsifying capacity and water-holding capacity increased while fat absorption and foaming capacity decreased with increasing DH. All hydrolysates showed greater fat absorption than the water-soluble fraction from undigested cuttlefish by-product proteins and casein. CPHs were also analysed for their ACE-inhibitory activity. CPH3 (DH 13.5%) displayed the highest ACE inhibition (79%), with an IC(50) value of 1 mg mL(-1).


CONCLUSIONS
Hydrolysis of cuttlefish by-product proteins with alkaline proteases from B. licheniformis resulted in a product with excellent solubility over a wide pH range and high ACE-inhibitory activity. This study suggests that CPHs could be utilised to develop functional foods for prevention of hypertension.
Balti
Rafik
R
Laboratoire de Génie Enzymatique et de Microbiologie, Ecole Nationale d'Ingénieurs de Sfax, BP 1173, 3038 Sfax, Tunisia.
Bougatef
Ali
A
El-Hadj Ali
Nedra
N
Zekri
Dorra
D
Barkia
Ahmed
A
Nasri
Moncef
M
D000803:Angiotensin I / Q000037:antagonists & inhibitors*; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D001407:Bacillus / Q000737:chemistry; D001426:Bacterial Proteins / Q000494:pharmacology; D049832:Decapodiformes; D010450:Endopeptidases / Q000494:pharmacology; D005223:Fats / Q000737:chemistry; D029941:Fish Proteins / Q000378:metabolism*; D005511:Food Handling; D006868:Hydrolysis; D007220:Industrial Waste; D011492:Protein Hydrolysates / Q000737:chemistry / Q000494:pharmacology*; D011817:Rabbits; D014416:Tunisia
D000806:Angiotensin-Converting Enzyme Inhibitors; D001426:Bacterial Proteins; D005223:Fats; D029941:Fish Proteins; D007220:Industrial Waste; D011492:Protein Hydrolysates; D000803:Angiotensin I; D010450:Endopeptidases; C087822:alkaline protease