Shelf Life Of Steaks Research Articles

53 Oxygen Exposure Effects on the Biochemical Attributes oflongissimus Lumborum Muscle During Retail Display

Abstract Limited studies have compared the effects of oxygen within a steak on biochemical properties. The objective was to evaluate the effects of oxygen exposure on the biochemical attributes of longissimus lumborum muscle. Steaks were (1.91 cm) sliced from USDA Low Choice beef strip loins (n = 7), packaged in polyvinyl chloride overwrap trays, and randomly assigned to day 3 or day 6 in retail display. During display, instrumental color was evaluated daily using a HunterLab MiniScan spectrophotometer. The display surface was considered as oxygen exposed (OE), while the interior of the steak was denoted as not exposed to oxygen (NOE). NOE was obtained by slicing the steak in half parallel to the previously OE surface. The NOE pieces were evaluated for bloom, while NOE and OE surfaces were used oxygen consumption (OC) and metmyoglobin reducing ability (MRA). Nitrite-induced metmyoglobin reduction was used to measure MRA, while changes in deoxymyoglobin level with vacuum were used as an indicator of OC. The data were analyzed using the GLIMMIX Procedure of SAS (n = 7 replications) and considered significance at P < 0.05. With increased display time, the a* values (redness) decreased (P < 0.05) for instrumental color. NOE steak surface had greater (P < 0.05) MRA compared with OE surfaces. Oxygen exposure affected the OC of the steaks, with the OE surfaces having lower (P < 0.05) OC compared to NOE surfaces on day 6 of display. The exposure of oxygen to the muscle resulted in a decrease in activity, paralleling in decline in retail color and color stability. In conclusion, the presence of oxygen can result in negative impacts on the shelf life of steaks; however, the non-exposed interior of muscle remains more biochemically active.

METHOD OF EXPRESS DIAGNOSTICS OF FISHSEMI-FINISHED PRODUCTS

Background. The main aspects of quality assessment of fish raw materials and combi ovens for its heat treatment are considered. The results of connection researches of structural and mechanical properties of raw materials with its thermophysical charac­teristics and parameters of necessary culinary processing are presented. The expediency of using physical methods for assessing the quality of raw materials to predict the mode of heat treatment is determined. The aim of the study is to develop a system of rapid diagnostics of structural-mecha­nical and thermophysical properties of fish semi-finished products for the insti­tutions of the HoReCa industry. Materials and methods. The object of research is the structural-mechanical and thermophysical properties of grass carp and their changes during storage. The subject of research – culinary semi-finished products, specifically – grass carp steaks. Determination of structural and mechanical properties of steaks was carried out by a measuring sensor of original design, developed on the basis of components of ITM LLC. The heating kinetics of grass carp semi-finished products were performed in a PolEco cabinet at a temperature of 180 ºC and forced convection. The temperature in the samples was recorded by standard thermal sensors of the UMCD with a measure­ment period of 20 seconds. The amount of active electricity, consumed for the preparation of steaks, was determined excluding the reactive component, by using current measuring clamp. Culinary processing of steaks was in the steam convection oven Convotherm OEB 6.10. Results. A set of structural and mechanical properties of grass carp steaks with different shelf life was determined with a sensor of the original design of UMCD. The correlation of changes in the indicators of adhesion, penetration and relaxation force after compression with the shelf life of steaks was established. A correlation between the shelf life and the heating speed of the samples was established with a standard thermo sensors of UMCD. The heating speed of the samples after 24 h of storage increases by 10–11 %. By recording the current in the power cable of the combi steamer, the electricity consumption for cooking 12 portions of steaks (2400 g) was determined. The possibility of saving electricity from 4.6 % for cooking freshly asleep fish and up to 16.5 % for chilled fish stored for 24 hours was established. Conclusion. The measuring sensor was tested. It allows determining the rela­xation, strength and adhesion of fish raw materials in the express mode. It was found that the structural-mechanical and thermophysical properties of grass carp change with storage time. It is experimentally confirmed that the change of information parameters of heat treatment in the steam convection oven is a criterion of quality of culinary products from freshwater fish. The developed method of express diagnostics allows determining the rheological properties of raw materials from freshwater fish and optimizing the heat treatment of culinary products in restaurants in terms of differential quality of raw materials. Due to the selection of individual processing modes for fish raw materials of different consistency and shelf life, it is possible to reduce electricity consumption by the steam convection oven by 4.6–22.4 %.

Effects of red macroalgae Asparagopsis taxiformis supplementation on the shelf life of fresh whole muscle beef.

This study was conducted to evaluate the effect of red macroalgae Asparagopsis taxiformis supplementation for cattle on the shelf life of fresh beef steaks (longissimus dorsi). Three treatment groups (seven steers per treatment) included: 1) Control diet, 2) Control diet + 0.25% of macroalgae inclusion (low dose, LD), and 3) Control + 0.5% of macroalgae inclusion (high dose, HD). After the animals were harvested, the strip loins from all animals were collected and aged for 14 days at the meat lab of the University of California, Davis. Then the strip loins were cut into steaks, packaged, and placed on a retail display case for 6 days. During a retail display, instrumental color (L*, a*, and b*) of lean muscle and external fat surfaces were measured every 12 h. Bacterial counts for total aerobic mesophilic bacteria (AMB), aerobic psychrotrophic bacteria (APB), and lactic acid bacteria (LAB) were assessed on days 0, 3, and 6 of retail display. The thiobarbituric acid reactive substances (TBARS) analysis was conducted to measure the lipid oxidation and the pH was also assessed on days 0, 3, and 6. No interactive effect between treatments and time on the shelf life of steaks was observed. The HD red macroalgae supplement decreased (P < 0.05) the lightness (L*) of the surface muscle of the steaks, while the lightness of the external fat was not affected (P < 0.05) by treatments throughout the retail display. The external fat yellowness of the steaks was lower (P < 0.05) in LD and HD treatment groups compared with the control group. An increase (P < 0.05) in counts of AMB, APB, and LAB was observed on the steaks from the steers in the HD treatment group while steaks in Control and LD group had similar bacterial numbers throughout the retail display. The results indicated that the shelf life of steaks from cattle in LD group remained the same as that of the Control group, but the HD of A. taxiformis caused a darker color of steaks with higher microbial counts, which may lead to a shortened shelf life due to undesirable appearance and faster microbial spoilage.

Effect of long-term corn by-product feeding on beef quality, strip loin fatty acid profiles, and shelf life

The objective of this study was to evaluate the meat quality and shelf life of steaks from steers fed dried distillers grains with solubles (DDGS) or dried corn gluten feed (CGF) compared with soybean meal with corn (SBM) as a protein supplement from weaning to slaughter. Angus cross steers (n = 81; BW = 306 ± 26.1 kg) were randomly assigned to pens (n = 9) and fed a stocker diet of corn silage (75% of DM) with DDGS, CGF, or SBM and ground ear corn. After 84 d of stockering, 12 steers (BW = 397 ± 15.3 kg) were randomly selected from each treatment and finished using the same protein supplement at 25% of DM for 100 d. Carcass data were collected (24 h) and the longissimus lumborum was fabricated into steaks at 48 h postmortem. Steaks were assigned to proximate analysis, Warner-Bratzler shear force (7-, 14-, or 21-d aging), and retail display (1, 3, 6, or 9 d). Protein source did not affect carcass yield, quality, or longissimus lumborum composition (P > 0.05). After 7 d of aging, DDGS and CGF steaks were more tender (P < 0.01) than SBM, but were similar (P = 0.30) after 14 and 21 d of aging. Feeding corn by-products did not influence subjective overall color acceptance (P = 0.17) in this study, but acceptance declined over time (P < 0.01). Subjective redness was similar (P > 0.05) among diets except SBM steaks were more red (P < 0.01) than DDGS after 9 d. On d 3 and 6 of retail display, CGF steaks exhibited more discoloration (P < 0.04) than SBM or DDGS steaks. However, after 9 d DDGS steaks were more discolored (P < 0.01) than CGF or SBM. Objective L* was lighter for CGF (P < 0.04) over 9 d of display, and all treatments became darker (P < 0.01) as time increased. Redness (a*) declined (P < 0.01) over time with SBM steaks maintaining more color in the red spectrum than CGF and DDGS after 6 d of display. Protein source did not affect (P > 0.05) the rate of lipid oxidation. Total SFA concentrations were similar (P > 0.05) among treatments; however, total MUFA were less (P < 0.05) and total PUFA concentrations were greater (P < 0.05) in DDGS steaks compared with SBM or CGF steaks. These data show that DDGS or CGF can be fed as a protein supplement at 25% DM from weaning until slaughter while maintaining meat quality when compared with steers fed soybean meal as a protein supplement.