Determination of Package and Muscle Type Influence

PROJECT SUMMARY

Determination of Package and Muscle Type Influence on Proteolysis, Beef Flavor Contributing Free‐amino Acids, and Final Beef Flavor Character

Principle Investigator(s):: K. R. Vierck, J. F. Legako, and J. C. Brooks
Institution(s):: Texas Tech University
Completion Date:: June 2019

Background

In the current market, packaging types are rapidly changing due to advancements in research surrounding beef palatability, color, and shelf-life research. Many retailers are moving from a traditional high oxygen, polyvinyl overwrap packaging method to a more case ready, modified atmosphere packaging or vacuum packaging to gain the benefits of extended shelf life. However, the impact of individual packaging schemes on aging and flavor precursors has not been fully explored.

The objectives of this study were to determine: the influence of package and muscle type on post‐mortem proteolysis and subsequent release of flavor contributing free‐amino acids during storage and distribution as well as determine the influence of packaging and muscle type on final beef flavor character through volatile flavor compounds and descriptive sensory analysis.

Methodology

For this study, USDA Low Choice USDA Choice quality grade (Small⁰⁰‐Small¹⁰⁰ marbling score; A maturity) beef strip loins and top sirloin butts (n = 20/ subprimal) were collected from a Midwestern beef processor. Subprimals were wet aged for 7d and fabricated into 2.54 cm steaks. Steaks were randomly assigned to one of four packaging methods: high oxygen modified atmosphere (80% O2/20% CO2); carbon monoxide motherbag (0.4% CO/ 30% CO2/ 69.6% N2), rollstock, and polyvinyl overwrap packaging. Steaks designated to the overwrap treatment were stored in vacuum packaging until retail display.

Following fabrication, steaks were aged for an additional 14 d in the absence of light in their respective packaging, then subjected to retail display for 48 h in coﬃn‐style retail cases under continuous fluorescent lighting. After retail display, steaks were vacuum packaged and frozen at ‐20°C until further analysis.

Following cooking on clamshell grills to 71°C, steaks (n = 160) were evaluated by trained panelists for beef flavor identity, brown/roasted, bloody/serumy, fat‐like, liver‐like, oxidized, fishy, buttery, umami, salty, bitter, sour, overall juiciness, and overall tenderness, using continuous 10 cm line scales. Each scale was verbally anchored at each endpoint and midpoint (0 = extremely bland/extremely tough/extremely dry; 50 = neither tough nor tender/neither dry nor juicy; 100 = extremely intense/extremely tender/extremely juicy).

In addition to trained descriptive panel evaluation, cooked steaks (n = 160) were also subjected to volatile compound analysis and Warner‐Bratzler shear force analysis. Targeted compounds were selected from various flavor development pathways, including the Maillard reaction and lipid degradation. Raw steaks (n = 200) were homogenized in liquid nitrogen and used for evaluation of free amino acids and Western blot analysis for post‐mortem degradation of desmin and troponin‐T.

Findings

This research indicates high oxygen packaging has detrimental effects on flavor and tenderness. Additionally, in this study, packaging had a greater impact on tenderness and flavor than muscle. Steaks should be stored in an anerobic environment during aging and storage to create optimum flavor and tenderness.

Implications

Packaging method greatly impacts the types of flavors and tenderness produced by beef products. In this study, packaging had a greater impact on tenderness and flavor as measured, when compared to muscle. Proper selection of packages by processors can result in longer shelf life with a more tender, flavorful product.

Table 1. Major flavor attributes impacted by packaging type.

	Beef Flavor Identity¹	Brown/ Roasted	Bloody/ Serumy	Oxidized	Fishy	Umami	Bitter	Sour
Packaging type
Carbon monoxide²	34.8^b	31.2^ab	14.4^ab	29.4^b	23.6^b	22.6^b	10.5^b	11.7^b
High oxygen³	28.5^c	28.1^b	10.5^c	43.4^a	35.4^a	19.5^c	12.8^a	14.5^a
PVC overwrap⁴	39.2^a	33.7^a	13.6^b	23.7^c	17.9^c	25.2^a	8.8^c	10.1^b
Rollstock⁵	41.6^a	32.6^a	17.3^c	19.2^d	14.3^c	26.2^a	10.2^b	11.1^b
SEM⁶	1.5	1.5	1.4	2.1	2.2	0.9	0.7	0.9
P-value	< 0.001	0.004	< 0.001	< 0.001	< 0.001	< 0.001	< 0.001	< 0.001
Muscle
Gluteus medius	35.4	31.1	13.8	30.3	24.0	22.8	11.0	12.5
Longissimus lumborum	36.6	31.7	14.1	27.6	21.5	23.9	10.1	11.2
SEM	1.3	1.2	1.2	1.8	1.7	0.8	0.6	0.8
P-value	0.236	0.546	0.826	0.082	0.174	0.143	0.067	0.058
Packaging × Muscle
P-value	0.872	0.103	0.904	0.290	0.920	0.606	0.361	0.368

¹Trained sensory scores: 0 = absence of specific flavor, 100 = extremely intense.
²Carbon monoxide motherbag (0.4% CO/ 30% CO2/ 69.6% N2)
³High oxygen modified atmosphere packaging (80% O2/20% CO2)
⁴Polyvinyl overwrap; prior to retail display, OW steaks were stored in ROLL packaging.
⁵Rollstock.
⁶SE (largest) of the least squares means in the same main effect (packaging type or muscle). abcLeast squares means in the same main effect (packaging type or muscle) without a common superscript differ (P < 0.05).

Table 2. Major tenderness attributes impacted by packaging type.

	Desmin Relative Intensity	Warner-Bratzler shear force	Trained descriptive panel overall tenderness rating¹
Treatment
Packaging type
Carbon monoxide²	0.86^b	2.5^b	52.3^a
High oxygen³	0.94^a	3.0^a	48.0^b
Overwrap⁴	0.86^b	2.2^c	52.3^a
Rollstock⁵	0.85^b	2.5^bc	53.5^a
SEM⁶	0.04	0.1	1.5
P-value	< 0.001	< 0.001	0.031

¹Trained sensory scores: 0 = extremely tough/dry, 50 = neither tough nor tender, 100 = extremely tender.
²Carbon monoxide motherbag (0.4% CO/ 30% CO2/ 69.6% N2)
³High oxygen modified atmosphere packaging (80% O2/20% CO2)
⁴Polyvinyl overwrap; prior to retail display, OW steaks were stored in ROLL packaging.
⁵Rollstock. 6SE (largest) of the least squares means in the same main effect (packaging type or muscle).
^abcLeast squares means in the same main effect (packaging type or muscle) without a common superscript differ (P < 0.05).