Sodium lactate influences myoglobin redox stability in vitro

The effect of potassium lactate on the free amino acid composition, lipid oxidation, colour, microbiological, and sensory properties of ready-to-eat pastırma, a dry-cured and dried meat product

In this study, the effects of potassium lactate (PL, Potassium-L-2-hydroxy-propionate, Potassium-L-Lactate) usage (0%, 0.5%, 1.0%, 2.0% PL of curing mixture) in addition to NaCl and sodium nitrite as curing agent on the physico-chemical, microbiological and sensory properties of ready-to-eat pastırma were investigated. The usage of PL affected pastırma properties as pH (P < 0.01), TBARS (P < 0.01), salt (P < 0.01), residual nitrite content (P < 0.01), a* value (P < 0.01), microbial properties (P < 0.01) (total aerobic mesophylic bacteria, lactic acid bacteria, Micrococcus/Staphylococcus, yeast-mould count) and amino acid levels [lysine (P < 0.01), isoleucine (P < 0.01), leucine (P < 0.01), methionine (P < 0.05), phenylalanine (P < 0.01), valine (P < 0.05), threonine (P < 0.01), tryptophan (P < 0.05), aspartic acid (P < 0.05), glutamic acid (P < 0.05), asparagine (P < 0.05), serine (P < 0.01), histidine (P < 0.01), glycine (P < 0.01), alanine (P < 0.01), proline (P < 0.01), cystine (P < 0.05) and norvaline (P < 0.01)]. According to results of sensory analysis, the difference among pastırma samples including PL was not significant (P > 0.05).

Using Pretreatment of Carbon Monoxide Combined with Chlorine Dioxide and Lactic Acid to Maintain Quality of Vacuum-Packaged Fresh Beef

Due to microbial growth, beef easily gets corrupt in retail conditions, and the color and quality of the meat will be deteriorated. Therefore, hurdle technology, namely, pretreatment of carbon monoxide (CO), chlorine dioxide, and lactic acid, is used for vacuum-packaged beef to decontaminate beef and increase its quality stability. Beef was pretreated with 100% CO (C1), 100% CO and 50 mg/L chlorine dioxide (C2), and 100% CO and 50 mg/L chlorine dioxide and 30 g/L lactic acid (C3). The untreated samples were used as control (CK). During storage, thea⁎color parameters of C1, C2, and C3 were significantly higher than that of CK, indicating CO pretreatment is a good way to maintain color appearance of beef, and chlorine dioxide and lactic acid did not affect the color-protecting role of CO on beef. C3 showed the strongest antimicrobial activity with the lowest total viable counts, followed by C2, C1, and CK. Samples in C3 also showed the lowest total volatile basic nitrogen, pH, thiobarbituric acid reactive substance, and metmyoglobin during the mid-late storage. Moreover, C3 can keep beef with higher unsaturated fatty acids. In conclusion, CO pretreatment combined with chlorine dioxide and lactic acid displayed efficient antimicrobial and color-stability activity for vacuum-packaged beef. It would be a potential way to use pretreatment of CO combined with chlorine dioxide and lactic acid to maintain the quality of vacuum-packaged beef.

Influence of redox reactive iron, lactate, and succinate on the myoglobin redox stability and mitochondrial respiration

Metabolic intermediates of glycolysis and the tricarboxylic cycle can stabilize beef color through improved metmyoglobin-reducing activity. Inorganic redox reactive iron (RRI) forms are pro-oxidants that have been shown to oxidize myoglobin in model systems. This study investigated how RRI, in the presence of added metabolic intermediates lactate and succinate, influences myoglobin (Mb) redox stability and color of beef strip loin homogenates and how it affects mitochondrial respiration. Homogenates with added RRI and either lactate or succinate had lower (p < 0.05) a* values than control homogenates. Oxymyoglobin increased (p < 0.05) as ferrous ion increased in the lactate and succinate treatments. The presence of ferrous or ferric ions reduced the mitochondrial oxidation rates of lactate and succinate (p < 0.05). The benefit of color stability offered by the metabolic intermediates and mitochondria-assisted metmyoglobin reduction was reduced by inorganic iron ions.

Effect of early postmortem enhancement of calcium lactate/phosphate on quality attributes of beef round muscles under different packaging systems

The objective was to determine the influence of calcium lactate/phosphate enhancement on quality of beef round cuts in high-oxygen modified atmosphere (HiOx-MAP; 80% O2/20% CO2). Mm. semimembranosus (SM), semitendinosus (ST), and adductor (AD) were divided and assigned to water-injected control (CON), 3mM phosphate (STP), or 200mM calcium lactate/3mM phosphate (CAL/STP) treatments at 24h postmortem. Steaks (n=10) were vacuum packaged (VAC) and stored for 9days, then displayed for 7days in VAC or HiOx-MAP. Lipid oxidation, pH, surface color, star probe, and sensory characteristics were evaluated. HiOx-MAP resulted in greater lipid oxidation, more discoloration, and decreased sensory quality of steaks (P<0.05) compared to VAC. However, CAL/STP enhancement significantly reduced lipid oxidation of all steaks, decreased ST and SM star probe values, and improved tenderness of HiOx-MAP packaged AD and SM (P<0.05). Results suggest that CAL/STP enhancement has beneficial effects on lipid stability and sensory attributes of beef round cuts under HiOx-MAP.

Impact of sodium lactate and vinegar derivatives on the quality of fresh Italian pork sausage links

Sodium lactate and acetic acid derivatives were evaluated for their impact on fresh Italian pork sausage using commercial trimmings. Analysis over storage included total plate count (TPC), TBARS, sensory analysis, cooking loss, pH, and color. Treatments included: (a) vinegar and sodium lactate mixture (V), (b) sodium lactate (S), (c) positive control with BHA/BHT (B) and (d) negative control, seasoning only (C). Treatments S and V had lower TPC (P<0.05) from days 5 to 14 when compared to B and C. TBARS values increased (P<0.05) for C, S, and V while B did not change (P>0.05) over time. While CIE a* surface values for redness generally decreased over storage time for all treatments, B maintained more redness. There were few major differences in descriptive sensory evaluation over time, but S and V precluded early onset of rancidity, oxidation and other off-flavors contrary to some of the analytical results. Of consumers tested, 85.6% rated all treatments between like slightly and like very much.

Effect of succinate sodium on the metmyoglobin reduction and color stability of beef patties

In two experiments, the effect of succinate sodium on the metmyoglobin (MetMb) reduction and color stability of beef patties was investigated. In experiment 1, the ground-beef strip loins (longissimus dorsi muscle) were blended with different concentrations of succinate. Enhancing patties with 6 mM succinate significantly increased the MetMb-reducing ability and subsequent color stability during storage. In experiment 2, MetMb and different concentrations of succinate, lactate, and reduced nicotinamide adenine dinucleotide (NADH) were incubated with mitochondria, and their effect on meat MetMb reduction was investigated. Increasing the concentration of NADH and lactate increased MetMb reduction, but only succinate of 16 and 24 mM significantly decreased the relative MetMb percentage compared to other systems. This indicate that there are no significant differences between aerobic and anaerobic MetMb-reducing activities. In comparison to the systems of NADH-MetMb reduction (including the systems of lactate-MetMb reduction), the succinate-MetMb reduction systems are more stable and less affected by oxygen. More identification work is needed to obtain the more complete pathways on MetMb reduction.

Fresh and cooked color of dark-cutting beef can be altered by post-rigor enhancement with lactic acid

Fresh and cooked color of dark-cutting (DC) beef strip loins (mean pH=6.56) enhanced with 0.25, 0.50, 0.75 or 1.00% lactic acid (LA) were compared to non-enhanced DC and normal pH (NpH; mean pH=5.43) strip loins. Even though NpH steaks received the most (P<0.05) desirable fresh color scores, color scores for steaks from DC sections enhanced with 0.25% LA approached those of NpH steaks after the first day of retail display. Discoloration scores were also similar (P>0.05) among NpH and 0.25% LA-enhanced DC steaks throughout the 5 d of display. Fresh steaks from NpH strip loins were redder, as evidenced by greater (P<0.05) a(∗) values and lower (P<0.05) hue angles, than DC steaks and DC steaks enhanced with LA, regardless of concentration. However, cooked color scores and proportions of denatured myoglobin were similar (P>0.05) between untreated NpH steaks and DC steaks enhanced with 0.25% LA. Results from this study indicate that enhancing DC beef with LA may lead to the brightening of the fresh color and prevention of the persistent red cooked color, approaching that of NpH beef.

Primary structure of goat myoglobin

Color stability attributes of goat meat are different from those of sheep meat, possibly due to species-specific differences in myoglobin (Mb) biochemistry. An examination of post-genomic era protein databases revealed that the primary structure of goat Mb has not been determined. Therefore, our objective was to characterize the primary structure of goat Mb. Goat Mb was isolated from cardiac muscles employing ammonium sulfate precipitation and gel-filtration chromatography, and Edman degradation was utilized to determine the amino acid sequence. Sequence analyses of intact Mb as well as tryptic- and cyanogen bromide-peptides yielded the complete primary structure of goat Mb, which shared 98.7% similarity with sheep Mb. Similar to other livestock myoglobins goat Mb has 153 residues. Comparison of the sequences of goat and sheep myoglobins revealed two amino acid substitutions - THRgoat8GLNsheep and GLYgoat52GLUsheep. Goat Mb contains 12 histidine residues. As observed in other meat-producing livestock species, distal and proximal histidines, responsible for stabilizing the heme group and coordinating oxygen-binding, are conserved in goat Mb.