<p>Within the last decade, the
popularity and interest in dry-aging have constantly increased among both
consumers and producers. Dry-aging is a natural value-adding process where meat
is exposed to a controlled refrigerated environment without any protective
barrier during the aging process. This process leads to the development of
unique flavors in the final meat product. Although the prevalence of this
process is increasing, there are inconsistent reports regarding the impacts of
dry-aging on meat sensory attributes, especially on the flavor aspect. Given
that flavor generation is dependent on the composition and availability of
flavor precursors, the presence or absence of these precursors may contribute
to the inconsistency observed. Thus the main objective of the research
described here was to characterize the flavor precursors in dry-aged meat and
elucidate potential factors or mechanisms favoring to their production.</p>
<p> To achieve this objective, metabolomics
analysis was conducted in conjunction with various chemical analyses (free
amino acids, fatty acids, sugar content and volatile analysis), microbiome
profiling and meat quality analysis (tenderness, water holding capacity, color
stability, oxidative stability, microbial attributes and sensory analysis) to
identify the essential flavor precursors and their production process. In
addition, similar analyses were conducted using multiple meat sources
(grass-fed beef loins, cull cow beef loins and pork loins) aged by wet-aging
(WA), conventional dry-aging (DA), dry-aging in bag (DWA) and UV-light
dry-aging (UDA) to elucidate the impact of the different aging treatments on
meat quality, sensory attributes and flavor precursor availability.</p>
<p>Regardless of the meat source,
the results demonstrated that dry-aging altered the meat flavor precursor
compositions, primarily by increasing the presence of protein-derived
precursors (e.g., free amino acids and dipeptides), especially glutamine and
glutamate compounds. Additionally, nucleotide and carbohydrate-derived
compounds such as adenosine and reducing sugars were greatly increased after the
dry-aging process. While the fatty acid profile was minimally affected,
metabolomics analysis revealed a decrease in sterol and terpenoid lipids following
dry-aging, which could potentially reduce off-flavors development in the meat.
Other compounds such as vitamin B and vitamin C were also detected in the
dry-aged product, which potentially could contribute to the flavor development.</p>
<p>Analysis of the liberation
mechanisms demonstrated that dehydration played a role in increasing the
concentration of the flavor precursors in the dry-aged product, potentially
promoting greater (e.g., Maillard reaction) during cooking. Furthermore,
microorganisms might be responsible for further increasing the availability of
flavor precursors in dry-aged meat, especially free amino acids, along with the
dehydration process. Microbiome profiling found that <i>Pseudomonas</i> spp. are the most prominent bacterial species in
microbial communities found on dry-aged meat which could affect the precursor
release in dry-aged meat. Metabolomics analysis also indicated increased
glutathione metabolism during dry-aging, which could lead to the liberation of
glutamine-related compounds. The analysis also identified other compounds such
as porphyrin rings (iron-related) and shikimic acid (bacterial metabolism),
providing further examples of how metabolomics can identify dry-aged flavor
precursors and reveal other potential mechanisms related to flavor development
mechanisms.</p>
<p>These outcomes demonstrate that
dry-aging alters meat flavor precursor composition, mainly by increasing the
availability of protein-, nucleotide- and carbohydrate-derived compounds. Such
results indicate that the Maillard reaction is likely be the main mechanism in
flavor generation in dry-aged meat. The current results provided more insights
into the dry-aging flavor development, especially highlighting important flavor
precursor such as glutamate and glutamine containing products, likely to
contribute to the dry-aged flavor. Future study to identify the impact of
different microorganism (especially mold and yeast) on dry-aging flavor
development would be of interest. Additionally, impact of different cooking
process should also be studies to maximize the dry-aged flavor potential from
the product.</p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/17124953 |
| Date | 20 December 2021 |
| Creators | Derico Setyabrata (11791949) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/thesis/CHARACTERIZATION_OF_DRY-AGED_MEAT_FLAVOR_PRECURSORS_AND_LIBERATION_MECHANISM_THROUGH_A_METABOLOMICS_APPROACH/17124953 |
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