Predicting Beef Tenderness Using Near-Infrared Spectroscopy

¹ Oklahoma State University, Stillwater 74075

^* To whom correspondence should be addressed. E-mail: bmorgan{at}okstate.edu.

	Abstract

The objective of this multiple-phase study was to determine the accuracy of an on-line near-infrared (NIR) spectral reflectance system to predict 14 d aged, cooked-beef tenderness. In Phase I, 278 carcasses (133 US Select, 145 US Choice) were selected (d-2) from two commercial beef processing facilities. Following carcass selection, longissimus lumborum (LL) muscle sections (ribs 9^th-12^th) were individually identified, vacuum-packaged, and transported to the Oklahoma State University Meats Laboratory where a 2.54-cm thick steak (n=1) was fabricated and stored in refrigerated conditions (1°C±1). Following a 30-minute oxygenation period, a NIR spectral scan was obtained on the 12^th-rib LL steak. Steaks (d-3) were individually vacuum-packaged and aged at 4°C for a total of 14-d prior to cooking slice shear force (SSF) analysis. In Phases II and III, 476 carcasses (258 US Select, 218 US Choice) were immediately NIR scanned following carcass presentation to in-plant USDA grading personnel. In a similar fashion, all LL steaks were aged (1°C±1) for 14-d prior to cooking (70°C) and conducting SSF. Of the Phase I and II samples, 39 (6.77%) were categorized as being "tough"(i.e. 25 kg SSF following the 14 d of postmortem aging period). Of these 39 "tough" samples, 20 (3.7% error rate) were correctly placed in the 90% certification level. Another 10 "tough" samples were placed in the 80% certification level (2.0% error rate). The overall NIR certified "tender" group was 1.67 kg more tender (P < 0.05) than LL samples from the non-certified samples. When the NIR predicted samples to be tough, 10% of the samples were eliminated from the Phase I and II LL populations at 90% cert. The population SSF mean improved in excess of 6.5 kg. For phase III, slice shear force evaluation by an independent, 3^rd party indicated the NIR system was able to successfully sort "tough" from "tender" LL samples to 70% certification levels. It was concluded that NIR scanning offers an in-plant opportunity to sort carcasses into tenderness outcome groups for guaranteed tender branded beef programs.

Key Words: Beef, Near-infrared, Quality grade, Tenderness