Improved jellyfish gelatin quality through ultrasound-assisted salt removal and an extraction process

Abstract

The use of by-products of salted jellyfish for gelatin production offers valuable gelatin products rather than animal feed. Several washes or washing machines have reported removing salt in salted jellyfish. However, the green ultrasound technique has never been reported for the desalination of salted jellyfish. The objectives were to determine how effectively the raw material’s salt removal was done by combining the traditional wash and then subjected to the ultrasonic waves in a sonication bath for 20–100 min. For gelatin production, the ultrasonicated jellyfish by-products were pretreated with sodium hydroxide and hydrochloric acid, washed, and extracted with hot water for 4, 6, and 8 h. Results showed that the increased duration of ultrasound time increased the desalination rate. The highest desalination rate of 100% was achieved using 100 min ultrasonic time operated at a fixed frequency (40 kHz) and power (220 W). The jellyfish gelatin extracted for 4, 6, and 8 h showed gel strengths in 121–447, 120–278, and 91–248 g. The 80 min ultrasonicated sample and hot water extraction for 8 h (JFG80-8) showed the highest gel yield of 32.69%, with a gel strength of 114.92 g. Still, the 40 min ultrasonicated sample with 4 h of extraction delivered the highest gel strength of 447.01 g (JFG40-4) and the lower yield of 10.60%. The melting and gelling temperatures of jellyfish gelatin from ultrasonicated samples ranged from 15–25°C and 5–12°C, which are lower than bovine gelatin (BG) and fish gelatin (FG). Monitored by FITR, the synergistic effect of extended sonication time (from 20–100 min) with 4 h extraction time at 80 °C caused amide I, II, and III changes. Based on the proteomic results, the peptide similarity of JFG40-4, having the highest gel strength, was 17, 23, or 20 peptides compared to either BG, FG, or JFG100-8 having the lowest gel strength. The 14 peptides were similarly found in all JFG40-4, BG, and FG samples. In conclusion, for the first time in this report, the improved jellyfish gel can be achieved when combined with traditional wash and 40 min ultrasonication of desalted jellyfish and extraction time of 4 h at 80 °C.

Exploring the Model of Cefazolin Released from Jellyfish Gelatin-Based Hydrogels as Affected by Glutaraldehyde

“…Compared to the same desalted jellyfish by-product, the sample was washed using a sonication bath, pre-treated with 0.2 M hydrochloric acid (HCl), and extracted at 80 • C for 4, 6, and 8 h. The results indicated that the gelatin yield was 7.43-32.69%. The highest gelatin yield obtained in this study was similar to that for the sample extracted at 80 • C for 8 h, at 32.69% [28]. The gelatin yield of the WO48 sample was higher than that in the previous work, which may have resulted from the raw material and extraction time.…”

“…The imino acid content in mammalian gelatin was reportedly higher than that in marine gelatin [30]. Compared to gelatin extracted from jellyfish in previous works, the gel strength of the WU24 sample in this work was higher than that of the desalted jellyfish by-product gelatin after the sample was treated with 0.1 M HCl and extracted at 60 • C for 12 h (323.74 g) [27]; the desalted jellyfish by-product gelatin obtained when the sample was washed using a sonication bath for 40 min, pre-treated with 0.2 M HCl, and extracted at 80 • C for 4 h (447.01 g) [28]; and cannonball jellyfish gelatin soaked in 1.5% citric acid and extracted at 60 • C for 4.5 h (3.4 g) [31]. Compared to other marine gelatin samples, the gel strength of the WU24 sample showed lower strength than that of the tilapia skin gelatin after the sample was pre-treated with pepsin enzyme (5 units/g of the sample) and extracted at 55 • C for 6 h (725 g) [32].…”

“…Amide A occurs in the 3400-3440 cm −1 range and is related to a N-H stretching vibration, while amide B is related to the asymmetric stretching vibration of =C-H and NH 3 + . The position shifts of amide A and B bands to a lower wavenumber indicate that the N-H group of peptides participates in hydrogen bonds, and high-temperature extraction enhances the interactions of -NH 3 + groups between peptide chains [28]. Thus, the high-temperature extraction destroyed hydrogen bonds and broke collagen structures during gelatin extraction [36].…”

“…The amide III bands of jellyfish by-product gelatin samples had a lower wavenumber as the gelatin extraction temperature and time increased. Lueyot et al [28] reported that the amide I and III band intensities decreased with gelatin extraction time, and the extraction time was associated with the loss of molecular order in jellyfish gelatin. These results indicated that the higher degradation of jellyfish by-product gelatin extracted at higher temperatures and times affected the protein structure of the jellyfish by-product, including the α-chain, triple-helix structure, and functional groups in jellyfish by-product gelatin.…”