Key findings

This study found that the freezing of beef subprimals has minimal impact on markers of meat quality. Differences did occur for initial color but influence of freezing was reduced over display time. Freezing did impact juiciness perceived by a trained panel. Additionally, the use of nitrite-embedded film in a rollstock packaging system improves the visual redness of meat during a 28-day retail display for all freezing regiments. 

background

The freezing of beef is widely used in both commercial and retail settings to increase profitability based upon market trends and supply. The influences of long-term frozen storage are yet to be fully determined with most research focusing on freezing periods between 30 – 90 days. In addition to freezing of fresh products, vacuum packaging is a common practice that is used to increase the shelf-life of meat products compared to polyvinyl overwrap packing yet results in a less desirable meat color. The color of meat products is the primary driver in which consumers perceive the acceptability of meat and discoloration leads to large economic losses in the United States annually.   The primary objective of this study was to evaluate the impacts of freezing of whole muscle beef subprimals and freezing of subprimals that are thawed and processed into case-ready packages before being refrozen until retail display on both color stability and sensory attributes during a 28-day retail display. The secondary objective of this study was to evaluate the color and sensory performance of steaks in nitrite-embedded versus standard rollstock packaging film.

methodology

For this study, 36 paired beef strip loins and top sirloin butts were collected from USDA low Choice quality grade A skeletal maturity carcasses from a commercial beef processing facility. Subprimals were wet aged at 4ºC for 12 days, then randomly assigned to one of three freezing treatments: frozen as a subprimal for 180 days (SNGL), frozen as a subprimal for 90 days fabricated into steaks and refrozen for 90 days (DBL), or never frozen (CON). At their respective timepoints, subprimals were fabricated into steaks and steaks were randomly assigned to either a control (CON) or nitrite-embedded (NIT) rollstock film. Steaks were then put into coffin-style retail cases for 28 days under continuous fluorescent lighting. Every 12 hours steaks were evaluated for instrumental color measures and every 24 hours were evaluated for redness, saturation, and percent discoloration by a trained panel. On day 0, 14, and 28, measures of lipid oxidation, spoilage organisms, and purge loss were conducted. Steaks on day 0 of retail display were utilized for descriptive sensory analysis. 

results and discussion

This research indicates that freezing has minimal impact on meat flavor but extended freezing and freeze thaw cycles decrease meat juiciness. Likewise, freezing once or twice appreciably influenced purge percent which may have consequences for product yield and consumer acceptability. Additionally, freezing improved color at the beginning of retail display. Furthermore, nitrite-embedded film improves visual redness of steaks on day 0 and 14 but is similar to control rollstock film on day 28. 

industry Implications

Freezing of beef subprimals has minimal impact on visual color and color stability of steaks during retail display. Additionally, freezing does influence juiciness measures in steaks, but at a minimum which should not be detrimental to the common consumer. Finally, the use of nitrite-embedded film can be used to improve redness of steaks and improve consumer acceptability.