The impact of single antimicrobial intervention treatment with potassium lactate,sodium metasilicate,peroxyacetic acid,and acidified sodium chlorite on non-inoculated ground beef lipid,instrumental color,and sensory characteristics

The effect of using potassium lactate, sodium metasilicate, acidified sodium chlorite, or peroxyacetic acid as a single antimicrobial intervention on ground beef instrumental color, sensory color and odor characteristics, and lipid oxidation was evaluated. Prior to grinding, beef trimmings (90/10) were treated with 3% potassium lactate (KL), 4% sodium metasilicate (NMS), 200-ppm peroxyacetic acid (PAA), 1000-ppm acidified sodium chlorite (ASC), or left untreated (CON). Ground beef under simulated retail display was measured at 0, 1, 2, 3, and 7 of display for instrumental color, sensory characteristics, TBARS values, and pH to evaluate the impact of the treatments. The KL, NMS, PAA, and ASC were redder (a^∗; P < 0.05) than CON. All treatments were scored by sensory panelists to have a brighter (P < 0.05) red color than CON during days 1–3 of display. All treatments had less (P < 0.05) lipid oxidation than CON on days 0, 3, and 7 of display. These results suggest that the use of these antimicrobial compounds on beef trimmings prior to grinding may not adversely affect, and may improve bulk packaged ground beef quality characteristics.     

Effects of potassium lactate,sodium metasilicate,peroxyacetic acid,and acidified sodium chlorite on physical,chemical, and sensory properties of ground beef patties

Beef trimmings were treated with 3% potassium lactate (KL), 4% sodium metasilicate (NMS), 0.02% peroxyacetic acid (PAA) or 0.1% acidified sodium chlorite (ASC) or left untreated (CON). Beef trimmings were ground, pattied, and sampled for 7 days. Under simulated retail display, instrumental color, sensory characteristics, TBARS, pH, and Lee–Kramer shear force were measured to evaluate the impact of the treatments on the quality attributes. The NMS and PAA patties were redder (a^∗, P < 0.05) than CON on days 0–3. Panelists found KL, NMS, PAA, and ASC patties to have less (P < 0.05) or similar (P > 0.05) off odor to CON on days 0–3. The NMS and PAA treated patties had lower (P < 0.05) lipid oxidation than the CON at days 0, 3, and 7. Therefore, KL, NMS, PAA, and ASC treatments on beef trimmings can potentially improve or maintain quality attributes of beef patties.     

Lactate-mediated enzymatic reduction of metmyoglobin in vitro

This study examined the lactate-mediated enzymatic reduction of equine metmyoglobin (MMb) by using various lactate salts (sodium, potassium and calcium) and bovine m. triceps brachi extracts in vitro. The equine MMb was reduced by the assay mixture containing lactate, NAD⁺, and the muscle extract at pH 5.7. In the absence of the bovine muscle extract, NAD⁺ or l-lactate in the assay mixture, MMb reduction was not observed. Replacing l-lactate with d-lactate or adding oxalate (lactate dehydrogenase inhibitor) to the assay mixture resulted in no MMb reduction, suggesting that lactate dehydrogenase is involved in the MMb reduction, interacting with l-lactate and NAD⁺. An increase (P < 0.05) in the rate of MMb reduction was also observed with an increase of the amount of bovine muscle extract, NAD⁺ or lactate concentration in the assay mixture. There was no difference (P > 0.05) in the rate of MMb reduction when potassium lactate was added to the assay mixture instead of sodium lactate. The MMb reduction through the lactate–NAD⁺-muscle extract system was increased (P < 0.05) with an elevation in pH from 5.1 to 6.1. The results of this research confirm that the inclusion of l-lactate can induce the MMb reduction through the lactate– NAD⁺-enzyme coupling interaction.     

Color-stabilizing effect of lactate on ground beef is packaging-dependent

Previous research on lactate-induced color stability in ground beef did not address the potential influence of packaging. The objective of the present study was to examine the effects of lactate on the color stability of ground beef patties stored in different modified atmosphere packaging (MAP) systems. Ground beef patties with either 2.5% potassium lactate or no lactate were packaged in vacuum (VP), high-oxygen MAP (HIOX; 80% O₂ + 20% CO₂), carbon monoxide MAP (CO; 0.4% CO + 19.6% CO₂ + 80% N₂), or aerobic packaging (PVC) and stored for 0, 2, or 4 days at 2 °C. Lactate-treated patties were darker (P < 0.05; lower L∗ values) than control patties. Surface redness (a∗ values) was greater (P < 0.05) for lactate patties than the controls when stored in PVC, HIOX, and VP. However, lactate’s effects on a∗ values were not evident when packaged in CO (P > 0.05). The color-stabilizing effect of CO could have masked lactate’s effect on surface redness. While lactate patties in PVC and VP demonstrated lower (P < 0.05) discoloration than controls, no differences (P > 0.05) existed between controls and lactate samples in CO and HIOX. Our results indicated that the effects of lactate on ground beef color are dependent on packaging.     

Effect of applying molasses or inoculants containing homofermentative or heterofermentative bacteria at two rates on the fermentation and aerobic stability of corn silage

This study determined how the fermentation and aerobic stability of corn silage are affected by treatment with molasses or 2 dual-purpose inoculants applied at or above the recommended rate. Corn forage (DeKalb 69-70) was harvested at 39% dry matter (DM) and ensiled after treatment with no additives (control, CON), molasses (MOL), Buchneri 500 inoculant, or Pioneer 11C33 inoculant. Molasses was applied at 3% of forage DM. Buchneri 500 was applied at the recommended rate of 8 mg/kg fresh forage to supply 1 × 10⁵ cfu/g of Pediococcus pentosaceus 12455 and 4 × 10⁵ cfu/g of Lactobacillus buchneri 40788 (BB) or at twice the recommended rate (DBB). Pioneer 11C33 inoculant was applied at the recommended rate of 1.1 mg/kg fresh forage to supply 1 × 10⁵ cfu/g of a mixture of Lactobacillus plantarum, L. buchneri, and Enteroccocus faecium (PN) or at twice the recommended rate (DPN). Each treatment was applied in quadruplicate and the treated forages were ensiled within 20-L mini silos for 135 d at 18 to 35°C. Molasses-treated silages had greater ash and starch concentrations than CON silages and greater lactate and ethanol concentrations than other silages. Like CON silages, MOL silages had high yeast counts (>10⁵ cfu/g); consequently, they deteriorated within 30 h as shown by temperature increase. Inoculant-treated silages had lower lactate to acetate ratios than CON or MOL silages largely because they had greater acetate concentrations. Consequently, all inoculant-treated silages had fewer yeasts (<10⁵ cfu/g) and were more stable (>30 h) than CON and MOL silages. When applied at recommended rates, PN and BB had similar effects on silage chemical composition, fermentation, fungal counts, and aerobic stability, except for a lower lactate concentration in PN silages. Concentrations of VFA, and NH₃-N, pH, and extent of aerobic stability were similar for PN, DPN, BB, and DBB silages. However, lactate concentration was greater in DPN than in PN. In conclusion, MOL application increased ethanol and lactate concentration and did not improve aerobic stability. Both dual-purpose inoculants made the fermentation more heterolactic and thereby improved the aerobic stability of corn silage. Doubling the rate of application of either inoculant did not further improve fermentation or aerobic stability.     

The effect of sodium lactate,potassium lactate,carrageenan, whey protein concentrate,yeast extract and fungal proteinases on the cook yield and tenderness of bovine chuck muscles

This study evaluated the efficacy of injection with enhancement solutions containing sodium lactate (NaLac), potassium lactate (KLac), carrageenan, whey protein concentrate (WPC), yeast extract or fungal proteinases alone or in combination with NaCl at increasing the tenderness and cook yield of bovine M.supraspinatus and M. tricepsbrachii caput longum. Muscle sections (400 g) were injected with enhancement solutions at an injection rate of 110% to give specific residual concentrations as follows: 0.5% NaCl; 2% NaLac; 2% KLac; 0.5% NaCl + 1 or 2% NaLac; 0.5% NaCl + 1% KLac; 0.5% NaCl + 0.4% sodium tripolyphosphate (STPP) + 2% NaLac; 0.5% NaCl + 0.4% STPP, 1.5% WPC ± 0.5% NaCl, 1.0% carrageenan ± 0.5% NaCl, 0.5% yeast extract or 0.0005% and 0.001% fungal enzymes. Injection with solutions containing sodium or potassium lactates (alone or in combination with NaCl and STPP), WPC, carrageenan and yeast extract significantly (P < 0.05) decreased WBSF values and increased sensory tenderness ratings, compared to non-injected controls. All of these ingredients in water also significantly (P < 0.05) increased cook yield with the exception of yeast extract which had no significant effect. The fungal enzymes in a water carrier acted as effective tenderising agents in both muscles but when used at the higher level resulted in a significant decrease in percentage cook yield. Injection of the chuck muscles with these ingredients and water represents an effective method of improving their tenderness and in most cases also increasing percentage cook yield.     

A comparison of needle-free and needle-injection methods and solutions for enhancement of beef longissimus lumborum muscles

In Experiment 1, beef strip loins (n = 15) were halved and assigned to needle (N) or needle-free (NF) injection enhancement with a phosphate plus salt solution (PS) to determine effects on color, water-binding, and palatability. Pump yields tended (P = 0.08) to be higher for NF injection. Needle-injected steaks were darker (P < 0.05) on day 1 only. The NF treatment had greater instrumental tenderness and intensity of off-flavors but less cooking loss and beef flavor (both P < 0.05). In Experiment 2, strip loins (n = 28) were halved and assigned to one of four treatments: (1) N, or (2) NF injection with PS; (3) N, or (4) NF injection with a calcium lactate solution (CL) to determine effects on water-binding and palatability. Needle-free injection resulted in a greater incidence (P < 0.05) of off-flavors and abnormal texture. The PS solution resulted in greater (P < 0.05) instrumental, myofibrillar, and overall tenderness; greater juiciness; greater incidence of off-flavors and abnormal texture; and less (P < 0.05) connective tissue and cooking losses than CL. The PS and NF combination had the highest pumped yields and least cooking losses (both P < 0.05). Enhancing beef strip loins with PS and NF injection has potential to improve yield, tenderness, and juiciness but harm texture and flavor.     

Carcass and meat quality characteristics and fatty acid composition of tissues from Pietrain-crossed barrows and gilts fed an elevated monounsaturated fat diet

Fifty-one (Landrace∗Large White)∗Pietrain barrows and gilts were used to compare the effect of a diet rich in oleic acid (HO) by feeding a by-product of the olive industry (Greedy-Grass OLIVA®: 1.4% growing, 3.8% finishing) or a grain and soy diet (CONTROL) on carcass characteristics, meat quality and fatty acid profile of intramuscular and subcutaneous fat. Gilts had leaner (P < 0.05) carcasses with lower fat percentage in major primal cuts, and less (P < 0.05) saturated fat compared with barrows with no interaction (P > 0.05) between dietary treatment and gender. Source of dietary fat had no effect (P > 0.05) on primal cut yields, composition of major primal cuts, or carcass and meat quality characteristics. Intramuscular fat from HO fed pigs had higher (P < 0.05) percentage of saturated (SFA) and monounsaturated (MUFA) fatty acids, and lower (P < 0.05) polyunsaturated fatty acids (PUFA) and n-6:n-3 ratio compared with CONTROL animals (37.4% vs. 36.8%, 44.7% vs. 40.1%, 17.9% vs. 23.2%, and 18.9 vs. 21.8 ratio, respectively). Subcutaneous fat from pigs fed HO had greater (P < 0.05) MUFA percentage, lower (P < 0.05) SFA and PUFA percentage, and lower (P < 0.05) n-6:n-3 ratio than pigs fed CONTROL diet (51.4% vs. 48.0%, 30.5% vs. 32.9%, 18.1% vs. 20.1%, and 9.83 vs. 11.3 ratio, respectively). Intramuscular fat had higher proportion of SFA and lower of MUFA showing a higher degree of tissue saturation compared with subcutaneous fat. Feeding Greedy-Grass increased MUFA and decreased PUFA proportions in fat depots reducing the risk of production of carcasses that are soft and oily which result in lower technological and processing quality.     

Effect of exposure to light on physico-chemical quality attributes of sliced dry-cured Iberian ham under different packaging systems

Dry-cured Iberian ham slices were stored under vacuum and under two different atmospheres (N₂ = 70% N₂ + 30% CO₂; Ar = 70% Ar + 30% CO₂) and exposed to lightness or darkness. Physico-chemical, sensory and microbial analysis was carried out throughout 60 days storage. Vacuum samples showed the highest a*-value compared to N₂ and Ar after 30 (P < 0.05) and 60 days (P < 0.05). The influence of illumination during storage was evident after 60 days of storage, L* and a*-values being lower (P < 0.01) in hams exposed to light than those kept in darkness, which can be ascribed to the lower nitrosylmioglobin content in samples exposed to light after 60 days (P = 0.001). Ham slices stored in darkness showed the lowest TBARS values (P < 0.05) and hexanal content (P < 0.05) after 60 days. Slices of ham packed in vacuum showed lower TBARS values than N₂ and Ar batches (P = 0.001), these samples being perceived as more rancid (P < 0.05). The rest of the sensory attributes were not generally affected by gas mixture or illumination (P > 0.05).     

Effects of temperature and NaCl percentage on lipid oxidation in pork muscle and exploration of the controlling method using response surface methodology (RSM)

This study investigated the effects of temperature (15, 20, 25, 30 or 35 °C) and sodium chloride (NaCl) (0.5%, 1.0%, 2.0%, 3.0% or 4.0%) on lipid oxidation by measuring the peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) in minced pork muscle. Both temperature and NaCl showed significant (P < 0.05) pro-oxidant effect within studied range. The activation energy (92.35 kJ/mol) for PV was higher than that (65.66 kJ/mol) for TBARS, indicating that lipid primary oxidation was more affected by temperature than the secondary oxidation. Temperature and NaCl had extremely significant (P < 0.001) interaction for lipid oxidation. Elevating temperature could significantly (P < 0.05) decrease the threshold value of NaCl concentration affecting lipid oxidation in the minced pork muscle. Based on the results, a relatively high temperature and a moderate or slightly lower level of NaCl, are recommended conditions for the fastest lipid primary oxidation rate in pork muscle.     

Influence of genetic type and level of concentrate in the finishing diet on carcass and meat quality traits in beef heifers

Carcass and meat quality traits of thirty-six feedlot beef heifers from different genetic groups (GG) fed at two concentrate levels (CL) were evaluated using 12 - Nellore (NE), 12 - ½Angus x ½Nellore (AN) and 12 - ½Simmental x ½Nellore (SN) animals. Six heifers of each GG were randomly assigned into one of two treatments: concentrate at 0.8% or 1.2% of body weight (BW). Heifers fed concentrate at 0.8% of BW had greater (P < 0.05) dressing percentage. None of the proximate analysis components of the beef were affected (P > 0.05) by either CL or GG. Heifers from the AN group had higher (P < 0.05) carcass weights, 12th rib fat thickness and lower dressing percentage (P < 0.05) compared to the other groups. NE heifers had greater WBSF values (P < 0.05) than the other genetic groups. Data suggest that the concentrate level can be reduced without compromising meat quality traits.     

Conjugated linoleic acids content in M.longissimus dorsi of Hanwoo steers fed a concentrate supplemented with soybean oil,sodium bicarbonate-based monensin,fish oil

We hypothesized that increasing ruminal pH would lead to enrichment of adipose tissue with conjugated linoleic acid (CLA). Twenty-four Korean native (Hanwoo) steers were used to investigate the additive effects of monensin (30 ppm, SO-BM) and/or fish oil (0.7%, SO-BMF) in the diets along with soybean oil (7%) and sodium bicarbonate (0.5%, SO-B) on cis-9, trans-11 and trans-10, cis-12 CLAs in adipose tissue. The steers were assigned to randomly four groups of six animals each based on body weight. The control group (CON) was fed a commercial concentrate for the late fattening stage. Supplementation of oil and sodium bicarbonate reduced feed intake and daily gain, and fish oil further decreased feed intake (P < 0.001) and daily gain (P < 0.087) compared to steers fed other diets. Total CLA and CLA isomers in M.longissimus dorsi were not affected when steers were fed SO-B and SO-BM diets compared with those of steers fed CON and SO-BMF diets. However, total poly unsaturated fatty acids were higher (P = 0.03) in steers fed SO than in CON steers.     

The effect of corn distiller's dried grains with solubles, ractopamine, and conjugated linoleic acid on the carcass performance, meat quality, and shelf-life characteristics of fresh pork following three different storage methods

The objective of this study was to evaluate dietary corn distiller's dried grains with solubles (DDGS), ractopamine hydrochloride (RAC), and conjugated linoleic acid (CLA) on growth performance, carcass and fat quality, and shelf-life of fresh pork from finishing pigs. Barrows (n = 72) were fed one of eight treatments consisting of two diet sources (corn-soy and corn-soy + 20% DDGS), two levels of RAC (0 and 7.4 ppm), and two levels of CLA (0 and 0.6%) for 28 days. Loins were portioned (n = 3) into one of three storage conditions (fresh, cold, frozen); each followed with seven days of retail display. Feeding RAC improved ADG and G:F (P < 0.05), whereas DDGS decreased belly fat firmness (P < 0.05). Dietary DDGS increased total polyunsaturated fatty acids in jowl and belly samples and increased Iodine Value (IV) (P < 0.05), but addition of CLA decreased IV. Dietary DDGS, RAC, or CLA had minimal impact on pork quality following varied storage methods.     

Effects of buffered vinegar and sodium dodecyl sulfate plus levulinic acid on Salmonella Typhimurium survival,shelf-life,and sensory characteristics of ground beef patties

The inclusion of two sources of buffered vinegar and sodium dodecyl sulfate plus levulinic acid were studied as interventions for Salmonella Typhimurium and for their effect on shelf-life and sensory characteristics of ground beef. For the Salmonella challenge, beef trimmings (80/20) were inoculated then treated with 2% (w/v) liquid buffered vinegar (LVIN), 2.5% (w/w) powdered buffered vinegar (PVIN), a solution containing 1.0% levulinic acid plus 0.1% sodium dodecyl sulfate (SDLA) at 10% (w/v), or had no intervention applied (CNT). The same trim source and production methods were followed during production of patties for shelf-life and sensory testing without inoculation. SDLA patties had the largest reduction (P < 0.05; 0.70 log CFU/g) of Salmonella. However, LVIN and PVIN had the least (P < 0.05) psychrotrophic growth. SDLA patties had more purge (P < 0.05) and lower (P < 0.05) subjective color scores. There were not large differences in sensory characteristics, except PVIN exhibited stronger off-flavor (P < 0.05).     

Sulfuryl fluoride fumigation effects on the safety,volatile composition,and sensory quality of dry cured ham

A randomized complete block design with three replications was utilized to evaluate the effects (P < 0.05) of various fumigation concentrations of sulfuryl fluoride (SF) (0, 12, 24, 36 and 72 mg/L) on the fluoride, sulfuryl fluoride, and volatile flavor compound concentrations in dry cured ham. Fluoride and SF concentrations increased (P < 0.05) in dry cured hams as SF fumigation concentration increased, but all samples contained fluoride and SF concentrations below the legal limits of 20 and 0.01 ppm, respectively. Minimal differences existed (P > 0.05) in the presence and concentration of aroma active compounds, but oxidation compounds were slightly more prevalent (P < 0.05) in the 72 mg/ml treatment when compared to the control. A triangle test (n = 54) indicated that consumers could not discern (P > 0.75) between hams that were fumigated with SF at 0 and 36 mg/ml. This study revealed that there were minimal aroma/flavor differences among the ham treatments between 0 and 36 mg/ml, and that dry cured ham that was fumigated with SF was safe and met legal requirements for consumption.     

Effects of lactate/phosphate injection enhancement on oxidation stability and protein degradation in early postmortem beef cuts packaged in high oxygen modified atmosphere

The influence of lactate/phosphate enhancement on meat color and lipid oxidation stability, tenderness, protein degradation, and protein aggregation of early postmortem beef muscles packaged in a high oxygen modified atmosphere packaging (HiOx-MAP; 80% O₂, 20% CO₂) were studied. At 24 hr postmortem, three bovine muscles (longissimus, semimembranosus, and adductor; n = 10, respectively) were enhanced (10% injection rate) with either lactate (2.5%)/phosphate (0.3%) solution or water, packaged in HiOx-MAP, stored 9 days at 1 °C, and then displayed for 7 days at 1 °C. The lactate/phosphate injection significantly improved color stability (higher a* values) of all three bovine muscles throughout display period. Accumulation of lipid oxidation determined by 2-thiobarbituric acid-reactive substances values was also decreased (P < 0.05) in the lactate/phosphate injection compared to the water treatment during storage and display periods. The objective tenderness values of longissimus and semimembranosus were also improved (P < 0.05) by the lactate/phosphate enhancement treatment compared to the water treatment based on star probe measurement. There were no significant differences found in desmin and troponin-T degradation, or oxidative cross-linking of myosin between treatments. The results suggest that lactate/phosphate enhancement has beneficial effects on color and lipid oxidation stability, and tenderness development of beef cuts under HiOx-MAP conditions.     

Increasing omega-3 levels through dietary co-extruded flaxseed supplementation negatively affects pork palatability

To clarify the impact of feeding co-extruded flaxseed on carcass quality and pork palatability, 96 pigs (48 barrows and 48 gilts) were fed three different levels of flaxseed (0%, 5% and 10% of dietary intake) for 76 days. Carcass quality and meat quality characteristics of pure loin muscle and ground pork (20% fat) were evaluated. Fat hardness and belly firmness decreased (P < 0.001) with increasing co-extruded flaxseed. Pigs fed co-extruded flaxseed levels had higher lean yield (P = 0.045) and total lean content (P = 0.034). Loin from barrows had higher fat content compared to gilts (P < 0.001). Co-extruded flaxseed supplementation increased (P < 0.001) omega-3 content in loin and ground pork. Pork flavour intensity and off-flavour intensity scores lowered (P < 0.001) with increasing levels of co-extruded flaxseed, being more accentuated (P = 0.023) in reheated pork chops from barrows. Diet affected all texture and flavour sensory characteristics (P < 0.05) as tissue levels of omega-3 fatty acids increased, likely as a result of increased lipid oxidation.     

Processing temperature, alcohol and carbonation levels and their impact on pulsed electric fields (PEF) mitigation of selected characteristic microorganisms in beer

Beer was inoculated with Saccharomyces cerevisiae, Lactobacillus plantarum, Bacillus subtilis, and Salmonella Choleraesuis prior to pulsed electric fields (PEF) treatment at different levels of inlet temperature (≤ 4 °C pre-cooled and ≤ 14.7 °C ambient), alcohol (3.5 and 0.5%), and carbonation (degassed and carbonated). PEF was applied at the electric field strengths of 35-45, 35, and 35-40 kV/cm, with respective treatment times of 402-2296, 765, and 612-765 ??s, and corresponding energy densities of 530-2339, 707, and 707-739 kJ/l to investigate its germicidal efficacy with regard to beer processing temperature (PT), alcohol content, and carbonation. In pre-cooled and ambient-temperature PEF-processed beer, reductions in microbial count of 4.0 (PT ≤ 40.7 °C) and up to 8.4 log₁₀ (PT ≤ 68.7 °C) were achieved, respectively (P < 0.05); inactivation using ambient-temperature PEF processing was comparable to thermal pasteurization applied at 76 °C for 30 s (up to 8.3 log₁₀ reduction in count (P ≥ 0.05)). Electric field strength and treatment time were fitted using a response surface model indicating higher PEF resistances of B. subtilis and S. Choleraesuis in beer (P < 0.05) while energy density and processing temperature gradients fitted for these microorganisms could allow optimization of PEF beer treatment. No difference in microbial inactivation due to alcohol and carbonation levels was obtained, except for higher reductions (P < 0.05) of L. plantarum in 3.5% beer and of S. Choleraesuis in carbonated beer.     

Enhancing pork loin quality attributes through genotype,chilling method and ageing time

The experiment was conducted to examine opportunities for enhancing pork quality through the use of post-mortem ageing when combined with different chilling regimes. Large White (LW, n = 24) and Duroc × Large White (Duroc, n = 24) barrows were slaughtered and alternate carcass sides were either conventionally or blast-chilled. The longissimus thoracis et lumborum muscle was dissected from the carcass sides (24 h post-mortem) and trimmed of cover fat. Three sections (15 cm length) were vacuum packaged and assigned to 2, 7 or 14 days of ageing (2 °C) randomized within muscle location. Blast-chilled meat had lower purge (P = 0.009) and drip (P = 0.0009) losses and higher hue (P = 0.02) than conventionally chilled meat. However chilling by conventional or blast-chilling methods had no effect on sensory characteristics (P > 0.1). When breeds were compared, meat from Duroc barrows had lower moisture (P < 0.0001) and higher intramuscular fat content (P < 0.0001), L∗ (P = 0.0003) and hue (P = 0.007) values than LW. Overall tenderness (P = 0.005), juiciness (P = 0.0007) and palatability (P < 0.0001), as well as flavour intensity (P < 0.0001) and desirability (P < 0.0001) values were higher and undesirable flavours were lower (P < 0.0001) for meat from Duroc pigs, when compared with LW. Ageing increased purge loss (P < 0.0001), L∗ (P < 0.0001), hue (P < 0.0001), chroma (P < 0.0001) and content of protein (P = 0.002), with corresponding decreases (P < 0.0001) in drip loss and moisture content. Instrumental (P < 0.0001) and sensory (initial, P < 0.0001 and overall, P < 0.0001) tenderness increased from day 2 to 14. Therefore independent of chilling method, ageing improved quality of pork loins. Moreover ageing had greater effect on tenderness, while breed had greater effect on flavour which may be related to differences in intramuscular fat content.     

Lipid peroxidation,protein oxidant and antioxidant status of muscle,intestine and hepatopancreas for juvenile Jian carp (Cyprinus carpio var. Jian) fed graded levels of myo-inositol

Lipid peroxidation, protein oxidant and antioxidant status of muscle, intestine and hepatopancreas in juvenile Jian carp (Cyprinus carpio var. Jian) fed graded levels of myo-inositol (MI) (163.5, 232.7, 384.2, 535.8, 687.3, 838.8 and 990.3 mg/kg diet) for 60 days were investigated. Total tissue malondialdehyde (MDA) and protein carbonyl (PC) content showed a downward trend to a point (P < 0.05). Conversely, total tissue anti-hydroxyl radical (AHR), catalase (CAT), glutathione-S-transferase (GST), glutathione peroxidase (GPx), glutathione reducase (GR) activities and glutathione (GSH) content were generally higher in MI-supplemented diets than MI-unsupplemented diet (P < 0.05). Muscle and intestinal superoxide dismutase (SOD), and intestinal anti-superoxide anion (ASA) were increased by MI supplementation (P < 0.05), whereas these parameters in the other tissue showed no alterations (P > 0.05). These results indicated that antioxidant status was improved, and lipid peroxidation and protein oxidant were depressed in muscle, intestine and hepatopancreas by MI.