The Effect of Aging/Freezing Sequence and Freezing Rate on Quality Attributes of Beef Loins (M. longissimus lumborum)

Derico Setyabrata,Brad Kim,Jacob R Tuell

doi:10.22175/mmb.11234

Abstract

The objective of this study was to determine the effect of different aging/freezing sequences combined with different freezing rates on quality attributes of beef loins (M. longissimus lumborum). Loins from 1 side of 8 beef carcasses (USDA Low Choice grade) were obtained at 2 d postmortem, cut into 10 steaks (2.54 cm), and randomly assigned into 5 treatments, where factorial combinations of 2 aging/freezing sequences (aging first then freezing/thawing [AFT] and freezing first then thawing/aging [FTA]) and 2 freezing rates (fast freezing [FF] and slow freezing [SF]) were used and compared to an aged only (AO) treatment as a control. Samples frozen using the FF condition were found to have a critical freezing time (Tc) of 21.5 min while the SF counterpart had a Tc of 175 min. Histological observation showed more visually enlarged gaps between muscle fibers in the SF samples, regardless of aging/freezing sequence. The SF-FTA samples had a significantly higher purge/ thaw loss followed by FF-FTA, while the loss from FF-AFT, SF-AFT, and AO were not different from each other (P > 0.05), suggesting that freezing rate effect might be more profound when applied in FTA. Cook loss was higher in AO compared to both FTA treatments (P < 0.05); however, it was not different when compared to AFT (P > 0.05). A lower shear force value and higher troponin-T protein degradation were found in both AFT and FTA compared to AO (P < 0.05), which would be attributed to the ice-crystal damage due to freezing. These results suggest that aging/freezing sequence could be an overriding factor in determining major meat quality attributes of frozen/thawed meat over freezing rate. However, fast freezing could negate some quality defects associated with the FTA process.

Highlights

Freezing is one of the most effective and efficient methods used to prolong the shelf life of meat products (Kim et al, 2015)
One of the most well-known of these factors is rate of freezing, as it plays a critical role in determining the final meat quality attributes, affecting the size, shape and location of ice crystals formation within the frozen meat (Leygonie et al, 2012a; Kim et al, 2015, 2017)
The results in the current study showed that aging/ freezing sequence and freezing rate would affect the final quality attributes of frozen/thawed beef steaks

Summary

Introduction

Freezing is one of the most effective and efficient methods used to prolong the shelf life of meat products (Kim et al, 2015). Impaired water-holding capacity (WHC) and oxidative stability, as well as textural changes, are some quality defects frequently found in frozen/thawed products. These quality defects are mainly attributed to the cryo-damage within the muscle structure by the formation of ice crystals (Leygonie et al, 2012a). One of the most well-known of these factors is rate of freezing, as it plays a critical role in determining the final meat quality attributes, affecting the size, shape and location (intra- or extracellular) of ice crystals formation within the frozen meat (Leygonie et al, 2012a; Kim et al, 2015, 2017). It is generally accepted that a lesser extent of cryo-dam-

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