The effects of an alginate-based edible coating containing natural antioxidants rosemary and oregano essential oils on lipid oxidation, color preservation, water losses, texture and pH of beef steaks during 14 days of display were studied.

The essential oil, edible coating and beef antioxidant activities, and beef consumer acceptability were also investigated. The edible coatings decreased lipid oxidation of the meat compared to the control. The coating with oregano was most effective The coatings significantly decreased color losses, water losses and shear force compared to the control. The coatings had a significant effect on consumer perception of odor, flavor and overall acceptance of the beef.

In particular, the oregano coating showed significantly high values approximately 7 in a 9-point scale. Active edible coatings containing natural antioxidants could improve meat product stability and therefore have potential use in the food industry.

This is an open access article distributed under the terms of the Creative Commons Attribution Licensewhich permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist. Beef is among the most consumed meats worldwide. The meat has a high protein content and an abundance of minerals, vitamins and fatty acids [ 1 ]. Consumers associate several meat attributes with freshness at display. In particular, color and tenderness are some of the most important purchasing criteria [ 23 ]. Meat discoloration results from the conversion of oxymyoglobin MbO 2 to metmyoglobin MetMb and an interaction between discoloration and lipid oxidation processes has been demonstrated [ 4 ].

Lipid oxidation is the major cause of deterioration in meat quality during storage and processing [ 5 ]. The primary and secondary oxidation products modify flavor, color, texture and decrease nutritional quality [ 6 ]. Lipid oxidation is a very complex process initiated by peroxidation of the unsaturated fatty acid in phospholipid membranes to form primary oxidation products, hydroperoxides.

The hydroperoxides decompose into further secondary oxidation products, such as aldehydes, ketones, alkenes and alcohols that cause off-flavors and odors in meat, which negatively affect the acceptability and overall quality of meat and meat products [ 7 ]. The reactions responsible for myoglobin Mit dem brasilianischen model ana mara and lipid oxidation generate products that can act mutually to accelerate oxidation [ 4 ].

Hence, antioxidants are added to maintain mit dem brasilianischen model ana mara quality and shelf-life of meat and other lipid-rich products.

Antioxidants are capable of stabilizing free radicals by donating hydrogen H to free radicals, or accepting electrons from free radicals to form a complex [ 8 ]. Antioxidants are often lost during conversion of muscle to meat, processing and storage. Thus, adding them to the final product is one strategy used to minimize deterioration during storage and consequently increase the shelf-life of the product [ 7 ].

Synthetic antioxidants have been used extensively to minimize lipid oxidation in foods. However, due to an increasing concern about the safety of synthetic chemicals, the use of natural and bioactive compounds with antioxidant activity are preferred and have attracted the attention of researchers [ 9 — 11 ].

Essential oils EOs are natural compounds extracted from plants that exhibit antimicrobial and antioxidant properties, and therefore attract interest as additives in the food industry [ 12 ]. EOs from oregano Origanum vulgare L. The use and choice of EOs should consider the consumer sensory acceptability of the final product.

Indeed, due to their strong flavor, their direct use is often limited. To overcome this issue, EOs can be added into edible coatings, which have been suggested as an alternative food packaging to improve food safety and quality [ 1819 ]. In beef display, polyvinyl chloride film PVC packaging is generally used, however, the exposure to oxygen accelerates oxidative mit dem brasilianischen model ana mara and color mit dem brasilianischen model ana mara [ 20 ], resulting in a short shelf-life.

Edible coatings are typically formed using proteins and polysaccharides [ 21 ]. These films can be used to maintain the quality and prolong the shelf-life of foods by decreasing lipid oxidation, minimizing contact with oxygen, increasing water barrier properties and maintaining the flavor of the food [ 23 ].

Indeed, there is great interest in edible coatings due to their biocompatibility, biodegradability, broad application potential and use as carriers of functional ingredients [ 19 ]. Although limited research has been performed using edible coatings in red meats, their ability to maintain the quality of fish, chicken, fruits and vegetables, for example, has been well-demonstrated [ 24 — 31 ].

This study evaluated the effects of alginate-based edible coatings containing EOs rosemary and oregano on the quality, consumer acceptability and shelf-life of beef under refrigerated storage. Aluminum chloride, potassium ferricyanide and ferric chloride were from Vetec Brazil.

The average live weight was Then, the Longissimus dorsi LD was excised from the left half of the carcass from the seventh to the last lumbar vertebra.

Homogenous steaks of 2. For active edible coating, sexleksaker butik stockholm stora brost escort EOs were mixed with alginate solution 0. Steaks from each animal were randomly and equally divided into four groups: uncoated meat CON ; meat with edible coating EC ; edible coating with 0. Extracts were obtained by homogenization in tubes homogenizer for oils and coating and ultra turrax for meatcentrifugation 15 min, 4.

The upper layer 2. The ABTS-activated radical was diluted with ethanol to an absorbance of 0. DPPH scavenging activity was measured according to Li et al. The absorbance at nm was measured against a blank of pure mit dem brasilianischen model ana mara. The sample 5 g was mixed with TCA solution 7. Results were expressed as mg MDA kg -1 of meat. Lipid oxidation assays were performed at 1, 7 and 14 days of display.

Chroma and hue values were calculated as follows:. Water holding capacity WHC was determined as weight loss. The mit dem brasilianischen model ana mara samples were removed from their trays at 1, 7 and 14 days of storage and their individual weights recorded on a semi-analytical scale. For each sample, results were expressed as a percentage of weight loss relative to its initial weight day 0.

Maximum shear force N was determined using a texturometer TA. The microstructure analysis was performed according to Matumoto-Pintro et al. Meat samples at 1 day of display were frozen-fixed in liquid nitrogen and lyophilized. Samples were mit dem brasilianischen model ana mara on aluminum stubs and coated with a gold layer sputter coater, Bal-Tec, SCD The edible coatings were applied as described in section 2.

Consumers only assessed acceptability on samples displayed for 1 day due to the Brazilian habit of consuming unaged meat. Ninety consumers were randomly selected among students, employees and visitors within quotas of gender 46 men and 44 women and age Nine sessions were carried out, each with ten different consumers.

The meat was served in a randomized design to avoid order and carry-over effects [ 38 ]. A medium level was not included, as mit dem brasilianischen model ana mara by Font i Furnols et al. Consumers were asked to eat unsalted toasted bread and rinse their mouth with water before evaluating each sample, including the first sample.

Means and standard deviation were calculated mit dem brasilianischen model ana mara each variable. For consumer evaluation, the type of edible coating was considered a fixed factor and the consumer was considered a random factor, with nine replicates per treatment. The correlations between attributes were evaluated using the Pearson correlation coefficient. The antioxidant activity can vary depending on the assay used due to differences in the underlying chemistry of the assay and the type of molecules detected, for example.

Hence, at least two mit dem brasilianischen model ana mara methods are typically performed [ 4041 ]. This trend was mit dem brasilianischen model ana mara observed in the respective edible coatings and meat samples treated with the respective coatings Table 1. Natural antioxidants have good potential in the meat industry as they are rich in active compounds and may minimize deterioration during storage [ 742 ].

The data showed that the EOs were responsible for the antioxidant activity in the coating and EC does not mit dem brasilianischen model ana mara antioxidant activity.

The TBARS assay measures the secondary oxidation products responsible for oxidative rancidity [ 43 ]. The effect of the edible coatings on oxidative stability of the meat was evaluated throughout storage. This difference between oregano and rosemary could be due to the different chemical composition of their EOs. Rosemary has no major antioxidant component with presumable high antioxidant activity like phenols. On the other hand, oregano has the carvacrol terpenoid family as the main component comprising phenolic compounds, acting as antioxidants due to their high reactivity with peroxyl radicals, which are eliminated by H-donation [ 4445 ].

Oxidation is the main non-microbial factor responsible for the quality deterioration in foods and is one of the major reasons for consumer rejection and loss of quality during storage [ 46 ]. Lipid oxidative stability depends on the balance between antioxidant and pro-oxidant components [ 47 ]. This study shows that the use of natural antioxidant sources could be effective at preventing lipid oxidation in meat products mit dem brasilianischen model ana mara refrigerated storage.

Cardoso et al. Raeisi et al. Volpe et al. Song et al. Thus, an edible coating incorporating a natural antioxidant, such as EO, may improve the shelf-life of meat products by preventing its lipid oxidation. The optical properties of an edible coating can change the overall appearance of food, since coating color may vary depending on the mit dem brasilianischen model ana mara of material used for their production.

Moreover, in relation to meat, the typical form of Myoglobin, the principal protein responsible for meat color, associated with low oxygen concentration deoxymyoglobin—with edible coating or with oxygenation oxymyoglobin—without edible coating can influence meat purchasing decisions [ 2 ], so it was important to compare the color of the meat with and without an edible coating.

The committed structural and conformational stability of proteins caused by oxidative damage may result in rupture of the peptide sequence, interactions protein—protein such as formation or polymerization of aggregates mit dem brasilianischen model ana mara modification of the amino acid chains. These modifications caused by oxidative process may alter protein function and its structure. From the most relevant chemical modifications, the formation of protein cross-links and protein carbonylation have been associated with the muscle protein functionality losses and modifications of meat attributes as color, flavor and texture [ 51 ].

Also, the maintenance of exudates in the coated meat Table 4 darkens the color. Meat pigment, in the absence of oxygen, is in the form of deoxy or reduced Mb, which has a purple-red color. On air exposure, the pigment is oxygenated to form MbO 2conferring a bright red color to the meat [ 54 ]. No significant differences were found among the coated treatments.

Colors that exhibit low chroma values are considered pale [ 48 ] and in this study, CON showed a lower chroma value than coated meat throughout storage, which may not be appealing to consumers at purchase time. Fresh meat typically becomes less red and lighter after a few days.

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