Food Science of Animal Resources (Food Sci. Anim. Resour.) is an international, peer-reviewed bimonthly journal publishing original research and reviews on basic and applied aspects of the use of animal resources including the meat, egg, dairy, and edible insect/worm products. Food Sci. Anim. Resour. is published and distributed by the Korean Society for Food Science of Animal Resources.

The objective of this study was to evaluate the effects of photoperiod on meat quality, oxidative stability, and metabolites of broiler fillet (M. Pectoralis major) muscles. A total of 432 broilers was split among 4 photoperiod treatments [hours light(L):dark(D)]: 20L:4D, 18L:6D, 16L:8D, and 12L:12D. At 42 days, a total of 48 broilers (12 broilers/treatment) was randomly selected and harvested. At 1 day postmortem, fillet muscles were dissected and displayed for 7 days. No considerable impacts of photoperiods on general carcass and meat quality attributes, such as carcass weight, yield, pH, water-holding capacity, and shear force, were found (p > 0.05). However, color and oxidative stability were influenced by the photoperiod, where muscles from 20L:4D appeared lighter and more discolored, coupled with higher lipid oxidation (p < 0.05) and protein denaturation (p = 0.058) compared to 12L:12D. The UPLC–MS metabolomics identified that 20 metabolites were different between the 20L:4D and 12L:12D groups, and 15 were tentatively identified. In general, lower aromatic amino acids/dipeptides, and higher oxidized glutathione and guanine/methylated guanosine were observed in 20L:4D. These results suggest that a photoperiod would result in no considerable impact on initial meat quality, but extended photoperiods might negatively impact oxidative stability through an alteration of the muscle metabolites.

Long photoperiods are used in the broiler industry to maximize animal performance, though the impact on meat quality remains poorly understood. The current study evaluated the impact of photoperiod on functional/physicochemical properties and oxidative stability of meat through broiler processing. Ross 308 broilers (n = 432) were randomly assigned to 4 photoperiod treatments (hours in L = light, D = dark): 20L:4D, 18L:6D, 16L:8D, or 12L:12D with 6 pens per treatment. At 42 D of age, 2 broilers per pen (n = 12 per treatment) were harvested under standard conditions. Broiler tenderloin (M. Pectoralis minor) and leg muscles were removed at 1 D postmortem and frozen/stored at −40°C. After 24 h thawing at 2°C, the samples were deboned, ground, and formed into patties in 3 independent batches. Photoperiod had no impact on pH, water-holding capacity, textural profile, meat emulsion activity index, and thiol content (P > 0.05). The patties from 12L:12D and 16L:8D had lower CIE b∗ (yellowness) values than 18L:6D and 20L:4D (P < 0.05), whereas 12L:12D had lower chroma (color intensity) values than other treatments (P < 0.05). The meat from 20L:4D exhibited lower sarcoplasmic protein solubility than other treatments (P < 0.05), whereas both 20L:4D and 18L:6D exhibited lower total protein solubility than 12L:12D (P < 0.05). Higher transmission values (indication of protein denaturation) were observed in 20L:4D than in other treatments (P < 0.05), whereas 12L:12D also maintained lower values than both 18L:6D and 16L:8D (P < 0.05). There was an interaction (P < 0.05) between photoperiod and display storage on 2-thiobarbituric acid reactive substances values, where the patties from 12L:12D maintained less lipid oxidation compared with the patties from other treatments. Results of this study suggest photoperiod has limited impact on meat quality attributes, though rearing broilers with a 12L:12D lighting schedule may be beneficial in reducing protein denaturation and improving lipid stability.

Tenderness is an important sensory attribute to the overall eating experience of beef. Identifying novel methods to ensure consistent tenderness, especially in inherently tough cuts, is critical for the industry. This study investigated if tumbling without brine inclusion could be an effective method to improve the quality and palatability attributes of beef longissimus lumborum (LL) and semitendinosus (ST) steaks. Furthermore, interactions with postmortem aging were evaluated to determine how tumbling might affect protein degradation and muscle ultrastructure. At 5 d postmortem, pairs of LL and ST muscles from beef carcasses (n = 16) were bisected, vacuum packaged, and tumbled for 0, 40, 80, or 120 min. Sections were divided and subsequently aged an additional 0 or 10 d at 2 °C. Tumbling for any duration improved instrumental tenderness of LL (P < 0.001) but not ST (P > 0.05) steaks, regardless of aging time. Tumbling exacerbated moisture loss in both muscles shown by greater purge and cooking losses (P < 0.05). Myofibrillar fragmentation was induced through tumbling in both muscles (P < 0.001), which was supported by transmission electron microscopy images. Tumbling for 120 min followed by 10 d of aging resulted in less abundant intact troponin-T in both LL and ST (P < 0.05), as well as less intact desmin in ST (P < 0.05); however, calpain-1 autolysis was not affected by tumbling (P > 0.05). No effects of tumbling, aging, nor the interaction were found for the content and solubility of collagen (P > 0.05). Consumer panelists (n = 120/muscle) rated LL steaks tumbled for any duration higher for tenderness and overall liking compared to control steaks (P < 0.05). For ST, significant interactions were found for consumer liking of tenderness and juiciness. In general, tumbling without subsequent aging resulted in poorer juiciness than non-tumbled (P < 0.05), while at 10 d no differences in juiciness were found between treatments (P > 0.05). For ST steaks that were aged 10 d, 120 min of tumbling resulted in greater tenderness liking than non–tumbled steaks (P < 0.05). These results suggest that tumbling would result in myofibrillar fragmentation and may benefit the degradation of myofibrillar proteins; however, there would be negligible impacts on collagen. Accordingly, tumbling without brine inclusion alone may be sufficient to improve tenderness and overall liking of LL steaks, while combined tumbling with subsequent postmortem aging would be necessary to improve tenderness liking of ST. Tenderness is a primary driver to the overall eating experience of beef. Postmortem aging is applied to improve beef tenderness through the activity of endogenous proteolytic enzymes; however, certain inherently tough cuts may not reach acceptable levels of tenderness through aging alone. This study investigated if tumbling in the absence of a brine solution, coupled with subsequent postmortem aging, would be an effective strategy to improve the quality and palatability attributes of fresh beef loin (longissimus lumborum; LL) and eye of round (semitendinosus; ST) steaks. Regardless of aging, tumbling for 40, 80, or 120 min improved instrumental tenderness of LL but not ST steaks. Consumer panelists rated tumbled LL steaks to be more tender with greater overall liking compared to those that were not tumbled. Tumbling alone was insufficient to affect consumer liking of tenderness of ST steaks, although tumbling combined with subsequent aging improved tenderness liking. The results supported that tumbling would physically disrupt and fragment the myofibrillar structure, which may aid in the degradation of myofibrillar proteins during postmortem aging.

This study evaluated the impacts of in utero heat stress (IUHS) on the carcass and meat quality traits of offspring when market weight was reached. Twenty-four F1 Landrace × Large White gilts were blocked by body weight and allocated among thermoneutral (IUTN) or IUHS treatments from d 6 to d 59 of gestation. The offspring were raised under identical thermoneutral conditions, and gilts (n = 10/treatment) at market weight (117.3 ± 1.7 kg) were harvested. At 24 h postmortem, the loins (M. longissimus lumborum) were obtained, and sections were allocated among 1 d and 7 d aging treatments at 2 °C. Carcasses from IUHS pigs had lower head and heart weights (p < 0.05), as well as decreased loin muscle area (p < 0.05) compared to IUTN pigs. Loins from the IUHS group had a higher shear force value than the IUTN group (p < 0.05). Treatments had no other impacts on carcass and meat quality traits (p > 0.05), and Western blots suggested increased toughness of IUHS loins would not be attributed to proteolysis. These results suggest minimizing IUHS during the first half of gestation may be beneficial in improving pork yield and quality, though in general the effects of IUHS would be minimal.