B. Giménez

Nanoencapsulation of an active peptidic fraction from sea bream scales collagen

Sea bream scales were subjected to enzymatic hydrolysis with Esperase, and a peptide fraction with a molecular mass <3kDa (F3) was isolated by ultrafiltration. F3 was encapsulated in nanoliposomes made of partially purified phosphatidylcholine (PC). Concentrations of 3.1% and 1mg/ml for PC and F3, respectively, were established as the best entrapment protocol by response surface methodology. The liposomes entrapment efficiency and zeta potential were 74.6±0.9% and -40.8±0.67mV, respectively. The liposome size ranged from 66.2 to 214nm, with a mean diameter of 90.3nm and a polydispersity index of 0.25. The antioxidant activity and ACE inhibitory activity of the encapsulated peptide fraction (L-F3) remained constant after 8days at 4°C. Encapsulation preserved the biological activities of F3, and could therefore be an alternative to improve the stability of these compounds when applied to a food product.

Incorporation of liposomes containing squid tunic ACE‐inhibitory peptides into fish gelatin

BACKGROUND Hydrolysates from collagen of jumbo squid (Dosidicus gigas) tunics have shown excellent angiotensin I-converting enzyme (ACE)-inhibitory activity. However, peptides directly included in food systems may suffer a decrease in activity, which could be minimized by loading them into nanoliposomes. RESULTS A fraction of peptides with molecular weights <1 kDa obtained from hydrolyzed squid tunics, with reasonably high ACE-inhibitory activity (half-maximal inhibitory concentration IC50 = 0.096 g L(-1)), was encapsulated in phosphatidylcholine nanoliposomes. The peptide concentration affected the encapsulation efficiency and the stability of the resulting liposomes, which remained with a high zeta potential value (-54.3 mV) for at least 1 week at the most suitable peptide concentration. The optimal peptide concentration was established as 1.75 g L(-1). Liposomes obtained with this peptide concentration showed an encapsulation efficiency of 53%, a zeta potential of -59 mV, an average diameter of 70.3 nm and proved to be stable in the pH range 3-7 at 4 °C. CONCLUSION Liposomes containing ACE-inhibitory peptides were incorporated in fish gelatin without detriment to the rheological properties and thermal stability of the resulting cold-induced gel. The ACE-inhibitory activity of the peptide fraction, which was not affected by the encapsulation process, conferred the bioactive potential to the nanoliposome-containing gelatin gel.

Antioxidant, ACE-Inhibitory, and Antimicrobial Activities of Peptide Fractions Obtained From Dried Giant Squid Tunics

ABSTRACT Squid tunics were divided in two batches: freeze-dried and air-dried. Dried squid tunics were directly hydrolyzed with pepsin, Alcalase, and Esperase. Freeze-dried tunics showed better aptitude for hydrolysis than air-dried tunics. Pepsin showed the lowest efficiency in protein breakdown and gave hydrolysates with low antioxidant activity, whereas Alcalase and Esperase peptide fractions showed strong radical scavenging ability, ACE-inhibitory activity, and noticeable antimicrobial properties. B. cereus, B. coagulans, and D. hansenii were found to be the most sensitive bacteria. Dried squid tunics proved to be an alternative to a previously extracted gelatin for obtaining bioactive peptides.