Prediction of water holding capacity and pH in porcine longissimus lumborum using Raman spectroscopy

Eli Gjerlaug-Enger,Petter Vejle Andersen,Jens Petter Wold,Nils Kristian Afseth

doi:10.1016/j.meatsci.2020.108357

Eli Gjerlaug-Enger, Petter Vejle Andersen + Show 2 more

Open Access

https://doi.org/10.1016/j.meatsci.2020.108357

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Journal: Meat Science	Publication Date: Oct 22, 2020
Citations: 11	License type: cc-by

Affiliation: Norsvin (Norway), Fafo Foundation, Nofima

Abstract

The main purpose of this study was to investigate if Raman spectra recorded at the exact same position as drip loss measurements could improve prediction of drip loss in pork. One ventral and one dorsal cylindrical plug, cut from a standardized slice from Longissimus lumborum, were used to determine drip loss by EZ-DripLoss method and to collect Raman spectra, while ultimate pH was measured at another location. Partial least squares regression models were developed using spectra from each plug individually or averaged spectra from both plugs. The best models used spectra from the ventral plug, resulting in rcv2=0.75, root mean square error of cross-validation (RMSECV) = 1.27% and ratio of prediction to deviation (RPD) =2.0 for EZ-DripLoss and rcv2=0.72, RMSECV = 0.05 and RPD = 2.0 for ultimate pH. Results indicate that Raman spectroscopy can be used for rough screening of drip loss and pH in pork, and that the location chosen for collection of spectra can be very important for successful predictions.

Highlights

Water holding capacity (WHC) and postmortem decline of pH are two important quality indicators for pork
Measurement of pH is usually conducted by inserting a glass pH-probe directly into the meat, while WHC often is measured by gravimetrically determining drip formed from a defined slice of meat by the bag method (Honikel, 1998) or from cylindrical subsamples within the muscle by the EZ-DripLoss method (Rasmussen & Andersson, 1996)
drip loss (DL) was measured for two adjacent slices from each muscle, where one slice was used for Raman spectroscopy and the other was used as a control for estimation of standard error of the DL measurement

Summary

Introduction

Water holding capacity (WHC) and postmortem decline of pH are two important quality indicators for pork. Correlations between pHu and a range of different quality attributes have been documented, where some of the noteworthy ones include drip loss, tenderness, color and flavor (Huff-Lonergan et al, 2002). WHC is a complex quality attribute for pork, where factors such as pH, extent of proteolysis (Huff-Lonergan & Lonergan, 2005) and chemical composition (Lawrie, 1985), contribute to the amount of exudate formed postmortem. Excessive drip loss is contributing to loss of revenue for meat processors, but WHC is affecting other quality factors, such as eating quality (Hughes, Oiseth, Purslow, & Warner, 2014) and processing properties of pork (Torley, D’Arcy, & Trout, 2000). Measurements of pH and WHC are invasive and are often con ducted as spot checks in industrial settings, information on an in dividual basis is not available to meat processors. Measurement of pH is usually conducted by inserting a glass pH-probe directly into the meat, while WHC often is measured by gravimetrically determining drip formed from a defined slice of meat by the bag method (Honikel, 1998) or from cylindrical subsamples within the muscle by the EZ-DripLoss method (Rasmussen & Andersson, 1996)

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