Effect of in-the-bag dry-ageing on meat palatability and volatile compounds of cull cows and youthful steers

Assessment of water relaxometry of meat under different ageing processes using time domain nuclear magnetic resonance relaxometry

This study assessed water relaxometry of beef exposed to different ageing techniques by examining the inner and surface regions using time-domain nuclear magnetic resonance (TD-NMR) relaxometry. Beef strip loins were aged under vacuum (Wet), under vacuum using moisture absorbers (Abs), under vacuum using moisture absorbers and with mechanical tenderisation (AbsTend), or without any packaging (Dry). The ageing technique significantly influenced various meat parameters, including dehydration, total loss, and the moisture content of the meat surface. The transverse (T2) relaxation times provided a more sensitive indicator of the changes in meat water relaxometry than the longitudinal (T1) relaxation times. The Dry samples exhibited distinct differences in the T2 signals between the surface and inner regions of the meat. In particular, for the inner region, there were significant differences in signal areas between the Wet and Dry samples, and the Abs and AbsTend samples were positioned closely together between the Dry and Wet samples. The principal component analysis supported these findings: it indicated some differentiation among the ageing techniques in the score plot, but the differentiation was more pronounced when analysing the surface region. Additionally, there was a strong correlation between dehydration and the T2 values, leading to a clustering of the samples based on the ageing technique. The overlap between the Abs and AbsTend samples, situated between the Dry and Wet samples, suggests the potential of these treatments to produce meat with properties that are intermediate to Wet and Dry meat. Furthermore, tenderisation did not lead to greater dehydration.

Effect of different electrical stimulation systems on beef quality and palatability: Constant current compared to constant voltage

This study examined the effects of constant current electrical stimulation (CCES) compared to constant voltage electrical stimulation (CVES), when applied within the same beef carcass (n = 79), on longissimus thoracis et lumborum (LTL) quality and palatability. There was a stimulation method × time interaction for pH, with CCES reducing the 3 h post-mortem pH, but increasing the 72 h post-mortem pH compared to CVES (P < 0.001). The CCES decreased the meat subjective Japanese Meat Grading Agency (JMGA) colour scores (P < 0.05) and increased the objective L⁎ (P < 0.01), a⁎ (P < 0.05) and b⁎ (P < 0.05) colour values at 3 d post-mortem and L⁎ and b⁎ values (P < 0.05) during retail display compared to CVES, although the objective values from both stimulation methods were above established consumer acceptability thresholds. Additionally, CCES reduced the purge (P < 0.05) and drip (P < 0.01) losses, and tended to reduce shear force values (P = 0.089) compared to CVES, although these did not translate into differences in juiciness or tenderness evaluated by trained panelists (P > 0.1). Regarding flavour, the CCES meat had greater bloody/serumy flavour (P < 0.05) and corn aroma (P < 0.05), less unidentified aroma (P < 0.05), and tended to have greater corn flavour (P = 0.077) and less barnyard aroma (P = 0.079) than CVES meat. There were also increased concentrations of flavour-related volatile compounds including 2-methyl-butanal, 3-methyl-butanal and 2-5-dimethyl pyrazine levels (P < 0.05) with CCES. Overall, the CCES system slightly improved meat quality and flavour compared to CVES when applied to the same beef carcasses. Further consumer studies would be warranted to determine whether these differences translate into more acceptable meat.

Freezing/thawing as an accelerating process of wet- and dry-aged Nellore beef

This study aimed to evaluate the use of freezing/thawing as a way of accelerating the aging processes of beef from Nellore animals. Non-frozen (NF) or freezing/thawing (FT) strip loins were aged (for 14 and 28 days) using two systems: bone-in dry-aging (DA); boneless wet-aging (WA). FT-treated samples had greater weight losses (P < 0.05) during aging than NF-treated samples, especially using the DA process. However, the weight loss of the FT 14-days DA beef samples was comparable to that of NF 28-days DA. FT beef had lower fragmentation index and shear force values (P < 0.05), as well as its maximum sensorial tenderness was achieved earlier (P < 0.05) than the NF counterpart. With 28 days of aging, DA beef showed higher (P < 0.05) tenderness and juiciness scores and lower lightness values than WA beef. The FT process decreased the reducing capacity of meat samples, generating more metmyoglobin and lower amounts of chroma than NF. The expected volatile profile of DA beef was achieved faster in FT-treated samples, but the freezing treatments did not compromise the microbial count for either aging system. Our findings indicate that accelerated DA by the FT process could improve the palatability of Nellore beef, allowing the desired tenderness and flavor profile to be achieved in a shorter time, without increasing costs with weight losses or adversely affecting physicochemical, chemical, and microbial characteristics.

Effect of a novel steak fabrication method by trimming subcutaneous and intermuscular fats on palatability and calorie content of beef ribeye steaks

This study investigated the effects of a novel steak fabrication method, involving removal of both subcutaneous and intermuscular fats between the longissimus thoracis (LT) and spinalis dorsi (SD) muscles before cooking, on beef ribeye steak palatability and calorie content. Canada AA (n = 10) and AAA (n = 10) ribeyes were fabricated into steaks either with (fat-on) or without (fat-off) subcutaneous and intermuscular fats. Fat-on steaks had shorter cooking times and lower cooking losses than fat-off steaks (P < 0.001), regardless of quality grade. There were treatment × quality grade interactions for initial (P < 0.01) and sustainable juiciness (P < 0.05) of the LT samples and initial juiciness (P < 0.05) of the SD samples, with the fat-on AA samples being more juicy than the fat-off AA samples, but the AAA treatments were not different from each other. Regardless of quality grade, fewer panelist responses indicated livery flavour (P < 0.05) for fat-on compared to fat-off LT samples. Regardless of fat-on/fat-off treatment, AA compared to AAA samples had more responses for bloody/serumy (P < 0.01) and unidentified off-flavours (P < 0.05) in LT samples. However, AAA samples had more responses for metallic off-flavour in LT (P = 0.059) and SD (P < 0.05). There were no differences in calorie content between fat-on compared to fat-off steaks (P > 0.1) regardless of quality grade and muscle type, or between AA and AAA steaks regardless of cooking with fat-on or off (P > 0.1). Maintaining the subcutaneous and intermuscular fats while cooking will improve ribeye steak palatability without increasing calorie content, especially for leaner steaks.

Effects of in-the-bag dry-ageing on meat quality, palatability and volatile compounds of low-value beef cuts

This study evaluated the effects of in-the-bag dry-ageing (BDA) (21 and 42 d) on meat quality, palatability, and volatile compounds of clod heart, brisket, and flat iron cuts from steers. In all cuts, BDA increased moisture losses (P < 0.05), but this did not reduce the juiciness of 21 d BDA versus wet-aged (WA) steaks. In clod heart, BDA increased overall tenderness at 21 d compared to 21 d WA (P < 0.01). Regardless of ageing period, BDA of clod heart increased beef flavour and salty taste and decreased sour-dairy and stale/cardboard flavours and concentrations of volatile compounds derived from lipid oxidation compared to WA (P < 0.05). In brisket, BDA increased salty taste and fatty aroma and reduced bloody/serumy flavour, whereas decreased beef and buttery flavours and intensified some unpleasant aromas/flavours (P < 0.05) for both ageing periods. The BDA of flat iron increased several undesirable aromas/flavours and decreased sweet taste and beef and buttery flavours (P < 0.05), regardless of ageing period. Overall, BDA for 42 d decreased meat quality and palatability and increased concentrations of volatile compounds from lipid oxidation, especially in flat iron cuts. Value could be recovered by customizing BDA periods by cut.

Fermented mixed feed regulates intestinal microbial community and metabolism and alters pork flavor and umami

This study aimed to determine the effects of fermented mixed feed (FMF) supplementation (0%, 5% and 10%) on the intestinal microbial community and metabolism, and the compositions of volatile flavor compounds and inosine monophosphate (IMP) contents in the longissimus thoracis. In this study, 144 finishing pigs (Duroc × Berkshire × Jiaxing Black) were randomly allocated to 3 groups with 4 replicate pens per group and 12 pigs per pen. The experiment lasted 38 days after 4 days of acclimation. The 16S rRNA gene sequences and an untargeted metabolomics analysis showed FMF altered the profiles of microbes and metabolites in the colon. Heracles flash GC e-nose analysis showed that 10% FMF (treatment 3) had a greater influence on the compositions of volatile flavor compounds than 5% FMF (treatment 2). Compared to 0% FMF (treatment 1), the contents of total aldehydes, (E,E)-2,4-nonadienal, dodecanal, nonanal and 2-decenal were significantly increased by treatment 3, and treatment 3 increased IMP concentrations and gene expressions related to its synthesis. Correlations analysis showed significantly different microbes and metabolites had strong correlations with the contents of IMP and volatile flavor compounds. In conclusion, treatment 3 regulated intestinal microbial community and metabolism, that in turn altered the compositions of volatile compounds, which contributed to improving pork flavor and umami.

Effects of Chitosan/Collagen Peptides/Cinnamon Bark Essential Oil Composite Coating on the Quality of Dry-Aged Beef

The aim of this study was to evaluate the effects of the chitosan/collagen peptides/cinnamon bark essential oil composite coating on dry-aged beef. Chitosan (2%, w/v), collagen peptides (1%, w/v), and cinnamon bark essential oil (1%, v/v) were homogenized to obtain the coating. Beef samples were divided into three groups (traditional dry-ageing, in-bag dry-ageing, and coating and then dry-ageing) and dry-aged for 42 days. Physiochemical, microbial, and sensorial parameters of samples were determined during the dry-ageing process. There were no significant differences (p > 0.05) in pH values, shear force values, cooking loss, color, juiciness, tenderness, and flavor across groups. The total volatile base nitrogen value of the coating group was lower than those of the other two groups. Compared to traditional dry-ageing, in-bag and coating dry-ageing reduced (p < 0.05) many volatile compounds such as alcohols, aldehydes, ketones, and acetate. In-bag and coating dry-ageing had no impact on the fungal community, but changed the bacterial community by inhibiting Pseudomonas. This study demonstrates that the chitosan/collagen peptides/cinnamon bark essential oil coating reduces microbial spoilage during dry-ageing, and has a small influence on product quality.