Introduction
Pork sausages are an important product in the global meat market. The typical process for making sausage is a multi-step process: mixing, casing, curing, and ripening. There is a high demand for meat and meat products that meet customer standards for valuable nutritional components. Traditional testing for important components in meat is time-consuming and expensive. As is the case with most meat products, fat, protein, and moisture are of paramount importance in sausage analysis. NIR spectroscopy has been studied an analytical tool for measuring these components. Results have proven the feasibility of using NIR spectroscopy for fat, protein, and moisture analysis in sausage. Good results have also been obtained for other components, such as water activity, pH, dry matter, salt, and non-collagen muscle protein (NCMP).
Analytes
- Fat
- Protein
- Moisture
- Water Activity
- pH
- Dry Matter
- Salt
- Non-Collagen Muscle Protein (NCMP)
Summary of Published Papers, Articles, and Reference Materials
NIR spectroscopy is an accurate and validated method for measuring fat, protein, and moisture in many food products, including sausages. To apply NIR spectroscopy as an analytical tool for multi-step process measurement in sausage production, accurate measurements must be made on both the intact final product and the more homogenized mixture that is present before final packaging. One study tested the final sausage product for fat, protein, and moisture but created two sets of calibrations: one in the intact product and another using a homogenized mixed set which blended the intact product before scanning. Results showed good correlation for these parameters and were comparable for both sets. Another study measured different parameters such as water activity, pH, dry matter, salt, and NCMP. Homogenized blended samples were used to build the calibration models and the results were excellent. Multi-point quality measurement has potential as a Process Analytical Technology (PAT) tool for providing real-time feedback for process control.
Scientific References and Statistics
Quantitative Analysis of Pork Dry-Cured Sausages to Quality Control by NIR Spectroscopy – Gaitan-Jurado, Ortize-Somovilla, Espana-Espana, et al., Meat Science 78 (2008) 291-399
Intact and Homogenized Sausages
One hundred sausage samples at two different manufacturing stages were scanned in reflectance. Each set was scanned both intact and after blending for a total of four hundred samples.
| Intact: | |
|---|---|
| Fat | R² = 0.98 |
| Protein | R² = 0.93 |
| Moisture | R² = 0.97 |
| Homogenized: | |
| Fat | R² = 0.99 |
| Protein | R² = 0.98 |
| Moisture | R² = 0.97 |
Results were excellent for both calibration sets. While the results were slightly worse for the intact samples, the difference is small and the study proved that multi-point measuring of these parameters in sausage is feasible.
https://www.sciencedirect.com/science/article/abs/pii/S0309174007002355
Application of FT NIR Spectroscopy in the Determination of Basic Physical and Chemical Properties of Sausages – Prochazkova, Drackova, Salakova, et al., ACTA VET. BRNO 2010, 79
Homogenized
Forty-two samples were scanned in reflectance using an FT-NIR analyzer. Samples were blended before scanning. Each sample was scanned three times and the three spectra for each were averaged into one spectrum.
| Water Activity | R2= 0.997 |
| pH | R2= 0.966 |
| Dry Matter (%) | R2= 0.995 |
| Salt (%) | R2= 0.995 |
| NCMP (%) | R2= 0.965 |
| Fat (%) | R2= 0.996 |
All correlation coefficients were high and the results proved the feasibility of measuring physical and chemical properties of sausages. It is known that salt is not directly measurable by NIR spectroscopy because Na is not an organic molecule. However, changes in the salt content affect the highly absorbing water areas in the NIR wavelength range. Thus, an indirect correlation for salt is attainable using NIR spectroscopy.
https://actavet.vfu.cz/79/9/0101/