# Effect of salting process on the histological structure of salmon flesh

Olivier Loison, Weijunlang Jiang, Annie Venien, Oulyana Gaubain, Chantal

Cazevieille, Thierry Astruc

► To cite this version:

Olivier Loison, Weijunlang Jiang, Annie Venien, Oulyana Gaubain, Chantal Cazevieille, et al.. Effect of salting process on the histological structure of salmon flesh. International Symposium on Food Nutrition and Health, May 2017, Dalian, China. 2017. hal-01595471

HAL Id: hal-01595471

https://hal.science/hal-01595471

Submitted on 26 Sep 2017

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_1.png" /></figure>
# Effect of salting process on the histological structure of salmon flesh

Olivier Loison<fnref n="1" />, Weijunlang Jiang<fnref n="1" />, Annie Vénien<fnref n="1" />, Ouliana Gaubain<fnref n="1" />, Chantal Cazevieille<fnref n="2" />, Thierry Astruc<fnref n="1" />

<figure><img src="image_2.png" /></figure>

## Context and objectives

Atlantic Salmon, Salmo Salar, is composed of approximately 70% water, 19% protein, 10% lipid and 1% small nutrients.

Smoked salmon comes from the processing of fresh salmon: the fillets are removed from the fish, salted and then smoked. Salting can be carried out with dry salt or by brine injection.

<figure><img src="image_3.png" /></figure>

Our goal was to characterize the muscle structure of smoked salmon according to the salting process.

## Conclusions

<figure><img src="image_4.png" /></figure>

* **Effect of salting:**

- **Dry Salt:** causes solubilisation of sarcomeres at Z-lines.

- **Brine Injection:** causes the swelling of myofibrils. The increase in water holding capacity of myofibrillar proteins, is reflected by the swelling of myofibrils.

* **Effect of Smoking:** **not significant change** after salting.

## Material and Methods

### PROCESS

Control

Fillet (right): Dry Salt

Fillet (left): Brine Injection

Smoking

Optical Microscopy

<figure><img src="image_5.png" /></figure>

n=6

Transmission Electron Microscopy

Muscle samples

(1x1x1,5 cm)

<figure><img src="image_6.png" /></figure>

Cryofixation:

Isopentane cooled by liquid nitrogen

**Chemical fixation:** Glutaraldehyde 2.5% cacodylate buffer 0,1M, pH 6,4 and 6

<figure><img src="image_7.png" /></figure>

10 µm cryosections

<figure><img src="image_8.png" /></figure>

Staining

70 nm sections

Control

<figure><img src="image_9.png" /></figure>

HES

Sirius Red

<figure><img src="image_10.png" /></figure>

Olympus BX61 + camera DP 71

Image analysis (Image J)

<figure><img src="image_11.png" /></figure>

Double Contrast

<figure><img src="image_12.png" /></figure>

Ultrathin sections

<figure><img src="image_13.png" /></figure>

TECHNAI F20 200KV by FEI

<figure><img src="image_14.png" /></figure>

Control

Sarcoplasm

Sarcomere

Z line

I band

M line

A band

Mitochondria

Lipid

## Results

Control

<figure><img src="image_15.png" /></figure>

### Optical Microscopy

Brine Injection

<figure><img src="image_16.png" /></figure>

Brine Injection+Smoking

<figure><img src="image_17.png" /></figure>

Dry Salt

<figure><img src="image_18.png" /></figure>

Dry Salt+Smoking

<figure><img src="image_19.png" /></figure>

% Area of Extracellular Spaces/processes

<figure><img src="image_20.png" /></figure>

HES = 1/2 size of the extracellular spaces after brine injection.

Dry salt salting shows no difference in the extracellular size compared to control

Sirius red = no significant effect on the connective tissue (red).

### Transmission Electron Microscopy

Brine Injection

<figure><img src="image_21.png" /></figure>

Brine Injection + Smoking

<figure><img src="image_22.png" /></figure>

Myofibrils Swelling

Dry Salt

<figure><img src="image_23.png" /></figure>

Break Sarcomeres

Dry Salt + Smoking

<figure><img src="image_24.png" /></figure>

Salting substantially degrades muscle ultrastructure with in particular a significant solubilization of the Z-lines.

Salting by brine injection leads to swelling of the myofibrils and almost complete solubilization of the Z lines.

<figure><img src="image_25.png" /></figure>

<footnote n="1">¹ UR370 Qualité des Produits Animaux (QuaPA), Centre de recherches Auvergne-Rhône-Alpes, F-63122 St-Genès-Champanelle (France)</footnote>

<footnote n="2">² MRI-COMET, Hôpital Saint Eloi, F-34091 Montpellier (France)</footnote>