Effect of myrtle leaves integration in sheep diet and its addition as powder on leg meat' oxidative stability, physicochemical, microbiological and sensory properties during storage.

The synthetic antioxidant improved the shelf life of meat products; however, consumers start to reject them for health reason. For this, the natural antioxidants like Myrtle distillate leaves (MDL) could be an interesting alternative and potential natural antioxidant given their richness in bioactive compounds. This study aimed to test the effect of myrtle distillate leaves (MDL) as natural antioxidant in premortem phase as diet of cull ewes and in postmortem phase in form of powder added to deboned legs on meat' quality. All ewes received individually 500 g of hay and 750 g of concentrate for Control (C) group; for Myrt group, the concentrate was partially replaced (400 g) by pellets containing 30% MDL and 350 g concentrate. For each ewe, both legs were used for the experiment; one leg was treated with MDL powder and the other with Control. Meat from ewes' fed MDL presented better scores for red color, aftertaste and juiciness, than control group. Meat treated with MDL powder showed the highest values of total phenolic, α-tocopherol content and redness score with lower lipid oxidation (p < .05). The microbiological quality of meat was not affected by MDL. Myrtle distillate leaves could be used in different forms, in order to obtain higher meat product quality.

Fatty Acid and Multi-Isotopic Analysis (C, H, N, O) as a Tool to Differentiate and Valorise the Djebel Lamb from the Mountainous Region of Tunisia.

The objective of this study was to distinguish between the Tunisian Djebel lamb meat and meat from typical Tunisian production systems (PSs) through the fatty acids (FAs) profile and the stable isotope ratio analysis (SIRA). Thirty-five lambs from three different regions and PSs (D = Djebel, B = Bou-Rebiaa, and O = Ouesslatia) were considered for this purpose. The results demonstrated that the PS and the geographic origin strongly influenced the FA profile of lamb meat. It was possible to discriminate between the Djebel lamb meat and the rest of the dataset thanks to the quantification of the conjugated linoleic acids (CLA) and the branched chain FAs. Moreover, statistically different concentrations of saturated, monounsaturated and polyunsaturated FAs and a different n-6/n-3 ratio were found for grazing (D and BR) and indoor (O) lambs, making it possible to discriminate between them. As for the stable isotope ratio analysis, all parameters made it possible to distinguish among the three groups, primarily on the basis of the dietary regimen (δ(13C) and δ(15N)) and breeding area (δ(18O) and δ(2H)).

Effects of myrtle (Myrtus communis L.) essential oils as dietary antioxidant supplementation on carcass and meat quality of goat meat.

Despite the fact that the use of rosemary and thyme residues and essential oils in animal feeding was widely documented, that of myrtle is scarce. To test the hypothesis that myrtle essential oils (MEOs) could improve goats' carcass characteristics and meat quality traits, twenty-one male goats received a ration consisted of 40% oat hay and 60% concentrate. Experimental goat kids received the control diet supplemented with 0, 0.3 and 0.6% of myrtle essential oils (MEOs) for C, Myrt1 and Myrt2 groups respectively. The administration of MEO did not improve the daily DM intake (p > 0.05). Kids of C and Myrt2 groups had higher average daily gain than Myrt1 group (75 versus 55 g). The goats slaughtered at 19.9 kg of weight did not differ (p > 0.05) in carcass weights and carcass yield in terms of commercial dressing percentage (CDP = 41%) and real dressing percentage (RDP = 52%). The administration of MEO increased the meat polyphenol content, being higher in both Myrtle groups (87 versus. 56 µg gallic acid equivalents g-1 fresh matter, p < 0.05). Myrtle EO administration protected kids' meat against oxidation (0.48 versus. 0.91 mg MDA/kg of meat for Myrtle and C groups, respectively, at the 9th day of storage; p < 0.05). It could be useful to include MEO as a dietary supplement in goats' rations since it improves meat's oxidative status without negative effects on FA profile.

Physicochemical Characteristics, Fatty Acid Profile, Alpha-Tocopherol Content, and Lipid Oxidation of Meat from Ewes Fed Different Levels of Distilled Myrtle Residues.

The aim of this work was to study the sheep meat physicochemical traits as affected by distilled myrtle residues (MR) supplementation. For this, 27 culled ewes were divided into three groups receiving a ration composed by concentrate and hay for the Control group, concentrate and MR as a total substitute to hay for the Myrt-H group, or hay, less concentrate, and MR as a partial substitute to concentrate for the Myrt-C group. The meat chemical composition, pH, and color parameters were not affected by the MR intake. However, this animal's dietary treatment resulted in higher meat polyphenol and α-tocopherol content for both MR groups (9.38 and 8.05 vs. 3.04 µg g-1 DM for Myrt-H, Myrt-C, and Control, respectively). In addition, since day 3 of meat storage, the lipid oxidation was improved by MR intake being lower for both MR groups than the Control (0.51 vs. 1.11 mg MDA/kg of meat). The total polyunsaturated fatty acid (PUFA) and saturated fatty acid (SFA) were similar among groups. However, the meat of Myrt-H had the highest C18:2n-6 and total PUFAn-6. In conclusion, the MR intake could be useful given it increases the meat content of vitamin E and improves its oxidative status without negative effects on the FA profile.

The effect of Rosemary (Rosmarinus officinalis L.) distillation residues and linseed supply on fatty acid profile, meat colour, lipid oxidation and sensorial and hygienic quality of cull Barbarine ewes' meat.

To test the hypothesis that feeding cull ewes with Rosemary (Rosmarinus officinalis L.) distillation residues (RR) and linseed improves meat quality traits; fatty acid (FA) profile, lipid oxidation, meat colour, sensory and microbiological analysis were investigated. For this, 28 Barbarine ewes received 500 g of basal diet and 700 g of concentrate. Two groups received the control concentrate (CC) with, as basal diet, straw for CCC and straw plus 200 g of RR for RCC group. The two other groups received the concentrate containing 10% of linseed (LC) with straw for CLC and straw plus 200 g of RR for RLC group. The linseed intake increased n-3 PUFA (+28.7%) and C18:3n-3(+41%) and decreased n-6/n-3 ratio from 4.55 to 3.25; while the RR diet affected only the content of branched chain fatty acid in cull ewes' meat. Feeding RR combined to linseed delayed lipid oxidation at almost ½ at Day 9 (2.38 vs. 4.63 for RLC and CLC respectively). Meat from rosemary diet had higher tenderness and lower resilience. It is concluded that the meat obtained after rosemary and linseed supply can be regarded as healthier and shows higher quality traits and greater oxidation stability under chilling storage.