Characterization of Collagen Structure in Normal, Wooden Breast and Spaghetti Meat Chicken Fillets by FTIR Microspectroscopy and Histology.

Karen Wahlstrøm Sanden,Mona Elisabeth Pedersen,Ulrike Böcker,Nils Kristian Afseth,Nancy Pleshko,Ragni Ofstad,Vibeke Høst,Sissel Beate Rønning

doi:10.3390/foods10030548

Karen Wahlstrøm Sanden, Mona Elisabeth Pedersen + Show 6 more

Open Access

https://doi.org/10.3390/foods10030548

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Abstract

Recently, two chicken breast fillet abnormalities, termed Wooden Breast (WB) and Spaghetti Meat (SM), have become a challenge for the chicken meat industry. The two abnormalities share some overlapping morphological features, including myofiber necrosis, intramuscular fat deposition, and collagen fibrosis, but display very different textural properties. WB has a hard, rigid surface, while the SM has a soft and stringy surface. Connective tissue is affected in both WB and SM, and accordingly, this study’s objective was to investigate the major component of connective tissue, collagen. The collagen structure was compared with normal (NO) fillets using histological methods and Fourier transform infrared (FTIR) microspectroscopy and imaging. The histology analysis demonstrated an increase in the amount of connective tissue in the chicken abnormalities, particularly in the perimysium. The WB displayed a mixture of thin and thick collagen fibers, whereas the collagen fibers in SM were thinner, fewer, and shorter. For both, the collagen fibers were oriented in multiple directions. The FTIR data showed that WB contained more β-sheets than the NO and the SM fillets, whereas SM fillets expressed the lowest mature collagen fibers. This insight into the molecular changes can help to explain the underlying causes of the abnormalities.

Highlights

Published: 6 March 2021Some decades ago, the poultry industry detected the first signs of abnormalities on chicken breast, i.e., Pectoralis major muscles [1]
The collagen organization within NO, Wooden Breast (WB), and Spaghetti Meat (SM) chicken fillets was examined with microscopy and spectroscopic analysis
The histological images gave an overall view of connective tissue and muscle morphology, while Fourier transform infrared (FTIR) spectroscopy provided a more detailed characterization of the chemical and molecular structure of collagen

Summary

Introduction

The poultry industry detected the first signs of abnormalities on chicken breast, i.e., Pectoralis major muscles [1]. SM fillets are soft with separated muscle fibers resulting in a stringy, spaghetti-like appearance [3] These abnormalities make the meat appear unpleasant, resulting in the downgrading of WB and SM fillets. Both WB and SM abnormalities show similar morphological features in the muscles, such as fiber necrosis, inflammatory cell accumulation, and fibrosis [2,3,4]. Fibrosis occurs when the muscle fibers undergo necrosis, and the muscle fibers are replaced by connective tissue [5]

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