Ultraschall fir en verbesserten Afroen an d'Peeling vu Garnelen

Traditionell op Salz baséiert Reifung vu Garnelen kann d'Verbindung tëscht Schuel an Fleesch lëss, erfuerdert awer laang Soakzäiten a suergfälteg Salzkontroll fir Faarfverlooss, Séissegkeetsverloscht an beschiedegten Textur ze vermeiden. Rezent Fortschrëtter weisen datt Ultraschall d'Reifung ersetze oder verbesseren kann, duerch d'Beschleunegung vum Ausschmëlzen an dem Lëssene vun der Schuel, während d'Qualitéit vun de Garnelen erhalen bleift. Kritt wëssenschaftlech ënnerstëtzt Abléck, wéi Sonikatioun d'Veraarbechtungs-Effizienz an d'Qualitéit vum Ennprodukt vu gefruerene Garnelen verbesseren.

Garnelen ofschielen a seng Erausfuerderungen

Shrimp peeling is one of the largest cost drivers in crustacean processing. Cold-water species like Pandalus borealis exhibit a very strong muscle–shell attachment, making freshly caught shrimp extremely difficult to peel mechanically. To solve this, processors traditionally use brining or ice maturation for up to 1–3 days, allowing endogenous enzymes and salt diffusion to weaken the attachment. However:

• long soaks risk loss of red/yellow color,
• excessive salt uptake changes flavor and reduces sweetness,
• extended time increases microbial risk, and
• ice crystallization during freezing can damage tissue without adequate salt concentration.

A modern alternative is sonication, which acts physically (cavitation, microjets, shear forces) rather than chemically, providing both rapid thawing and accelerated shell loosening with minimal product degradation.

 

Discover the groundbreaking potential of intense airborne ultrasound with the Hielscher stepped plate resonator. This innovative technology leverages high-power ultrasonic waves for precise, non-contact applications such as drying, defoaming, thawing and precision cleaning. Compact, versatile, and robust, the resonator's advanced stepped geometry amplifies and focuses sound waves to deliver powerful energy, making it ideal for delicate and complex industrial processes. Whether you're in manufacturing, aerospace, food processing, pharmaceuticals, or materials research, this technology opens new doors to efficiency and innovation.

 

How Ultrasound Improves Thawing of Shrimp

Rapid heat transfer through cavitation

Ultrasound produces microscopic bubbles in the liquid surrounding the shrimp. These bubbles expand and collapse violently – a phenomenon called acoustic cavitation.
According to Li et al. (2024):
Ultrasound reduced thawing time from 87 min (air thawing) and 66 min (flow water thawing) down to 48 min, representing a 48.9% acceleration.

 

 

This occurs because collapsing cavitation bubbles:

• generate shockwaves and microjets,
• dënn d'thermesch Grenzschicht ronderëm d'Iessen
• an beschleunegt d'Méigen vum internen Äiskristaller.

Schutz géint Lipid-/Proteinoxidatioun

Li et al. (2024) weisen, datt d'Kombinatioun vun Ultraschall mat liicht basesch elektrolyséierter Waasser (SBEW) verhënnert:

• MDA (Lipidoxidatiounsmarkéierer) huet op 0,62 nmol/mg an Ultraschall + SBEW erofgaang vs 0,83 nmol/mg beim Loft-déierbaren Garnelen.
• Carbonylen (Proteinoxidatioun) waren am niddregsten bei Ultraschall-ënnerstëtzte SBEW-behandelte Garnelen (1,63 nmol/mg vs 3,21 nmol/mg fir Loftdéieren).

Preservatioun vun der Muskelstruktur a Waassererhalung

Ultraschall-Déieren (UST):

• erhaalt d'Muskel Faser Integritéit, wou Ultraschall-ënnerstëtzte SBEW-behandelte Proben dicht ausgeriicht Faser wéi bei frëschen Garnelen weisen.
• resultéiert an der niddregster Déierenverloscht (4,06%) an niddregstem Kachenverlust am Verglach zu allen aneren Methoden.

 

 

Ultrasonically-Improved Peeling of Shrimp

1. Cavitation physically weakens the shell–muscle interface

   Dang et al. (2018) found that power ultrasound at 24 kHz creates:

   • spiral pits on the shell surface,
   • erosion of the epicuticle layer,
   • increased porosity,
   • microchannels extending toward the membranous layer.

   These structural changes dramatically improve shell release.
   SEM images on page 37 clearly show pits on US-treated and US+enzyme-treated shrimp, while raw and enzyme-only samples remain smooth.

 

2. Ultrasound reduces peeling work and increases yield

   When used before or during enzyme maturation:

   • Peeling work decreased from 7.8 mJ/g (raw) to 3.9 mJ/g, a 50% reduction.
   • Meat yield increased (up to ~90% depending on condition).
   • Proportion of completely peeled shrimp increased significantly.



   Ultrasound alone already improves peelability; combined ultrasound + enzyme is even more powerful.

 

3. Enzyme diffusion enhanced through ultrasonic microchannels

   The proposed mechanism results in:

   1. Cavitation pits form “entry points” in the shell.
   2. These pits connect to deeper microchannels.
   3. Enzymes–whether endogenous or added–penetrate faster and hydrolyze the muscle-shell attachment.

   This allows:

   • shorter maturation (hours instead of 1–3 days),
   • less risk of color fading or sweetness loss,
   • lower salt requirements than brining.

 

4. Minimal impact on color and texture

   Unlike long salt soaks, ultrasound treatments:

   • did not change L*, a*, b* color parameters compared to raw shrimp,
   • did not damage texture (hardness, resilience, chewiness stayed comparable).

   This makes ultrasound far safer than over-maturation in brine, which is known to dull color and reduce sweetness.

Sonication Compared to Brining

Ultrasound provides a more controlled, faster, and cleaner mechanism than salt diffusion.

Parameter	Traditional Brine Maturation	Ultrasound-Based Methods
Zäit	12-48h	3-4h (US + enzyme)
Salt usage	héich	Nidder oder keen
Risiko vu Iwwerwaasserung	héich	Ganz niddreg
Schälen Aarbecht	mëttelméisseg	Réduzéiert bis zu 50%
Faarfschutz	Oft reduzéiert	Erhalen
séiss	Keng ofhängeg	Erhalen
Textur	Verloscht vu Spannkraft	Erhalen
Mikrobiellt Risiko	Héich (laang Prozesszäit)	Niddereg (kuerze Prozess)