Recovery of Tilapia (Oreochromis niloticus) Protein Isolate by High-Intensity Ultrasound-Aided Alkaline Isoelectric Solubilization/Precipitation Process

Abstract

High-intensity ultrasound (HIU), which is regarded as "green" technology, was combined with an alkaline pHshift process to extract tilapia (Oreochromis niloticus) protein isolate (TPI) at various pH conditions. The results showed that HIU significantly decreased the consistency of alkaline muscle homogenate, especially at less extreme pH (pH 10.5), increased the protein solubility, and reduced the sediment ratio. Alkaline volume needed for pH adjustment to the same pH level was slightly increased by HIU, indicating that HIU accelerated the charging of myofibril protein particles and strengthened the electrostatic repulsion forces. Aided by two HIUs, the protein recovery at pH 10.5 was increased from 47.0 to 62.6 %, which was equivalent to that (62.4 %) at pH 11.5 without HIU, suggesting that~40 % alkaline and corresponding acid in the process could be saved. SDS-PAGE images reveal that HIU induced partial degradation of titin and disassociation of nebulin with thin filament in sarcomere, which possibly facilitated the dispersion and solubilization of myofibril proteins. Those results of ATPase activity loss and surface hydrophobicity increase indicated that HIU also affected the conformation of the dissolved myofibril protein in muscle homogenate. TPI gel strength was elevated when the alkaline pH-shift process was aided by HIU.

Sea Bass Side Streams Valorization Assisted by Ultrasound. LC-MS/MS-IT Determination of Mycotoxins and Evaluation of Protein Yield, Molecular Size Distribution and Antioxidant Recovery

“…Lastly, 30 min of ultrasound at 50 • C and a pH 5.5, allowed the extraction of 99.37% of proteins from the viscera extracts. Similar protein recoveries were obtained by Tian et al [31]. These authors observed protein yields that reached 62.60% when they evaluated protein recovery from tilapia fillets assisted by UAE combined with alkaline conditions.…”

Protein Recovery from Underutilised Marine Bioresources for Product Development with Nutraceutical and Pharmaceutical Bioactivities

“…Such synergic effects disrupt cell walls and membranes, creating micro-cavities in the tissues which improves solvent penetration, resulting in the transformation of material structure and improved mass transfers, which in turn reduce processing time, solvent use and increase yields [386,387]. A 15.6% increase in extracted protein yields from tilapia was achieved with ultrasound-intensified ISP under alkaline condition [388]. Similarly, the protein yields of >95% [389,390] and 99% were achieved with ultrasonic extraction under alkaline conditions (pH 13) from mackerel by-products and lobster heads, respectively [19].…”

Positive effects and mechanism of ultrasound on chitin preparation from shrimp shells by co-fermentation

“…The lanes of A, B, and C all exhibited 20 kDa, 40 kDa, and 100 kDa protein bands. However, these protein bands disappeared when the ultrasound power increased to 600 W or 800 W. This indicates that ultrasound at high power (600, 800 W) induces the degradation of protein, which may promote the dispersion and solubilization of shrimp shell protein [33] . There have been very few particular proteins isolated from shrimp shells until now.…”