Gema Nieto

Dietary administration of ewe diets with a distillate from rosemary leaves (Rosmarinus officinalis L.): Influence on lamb meat quality

The effect of including distilled rosemary leaf in the diet of pregnant ewes on subsequent lamb meat quality was studied. Thirty-six Segureña ewes were randomly assigned to three homogeneous groups. One group was fed a basal diet (BD) as control while the diet of the other two groups was modified by substituting 10% (R(1)) and 20% (R(2)) of the BD with a pellet made from 50% barley and 50% of distilled rosemary leaves (DRL). Meat spoilage (TVC, PSY and MYC), TBARS, CIELab coordinates and the sensory characteristics contribution of fresh lamb meat packed in MAP (70% O(2):30% CO(2)) were analyzed on days 0, 7, 14 and 21. In general, R(1) and R(2) had higher a* values, better scores for meat and fat colour (P<0.05) and lower TBARS and rancid odour (P<0.05), than the control samples. The total viable count was lower in meat DRL. No statistically significant differences were detected between the two treatments (10-20% DRL).

Effect on lamb meat quality of including thyme (Thymus zygis ssp. gracilis) leaves in ewes' diet.

The aim of this study was to investigate the effect of including thyme leaves (TL) in the diet of pregnant sheep on the sensorial characteristics, bacterial spoilage and oxidative stability of lamb meat stored in modified atmosphere (70% O(2):30% CO(2)). For this, thirty-six sheep were randomly assigned to three groups: control (basal diet), T(1) (3.7% thyme leaves), T(2) (7.5% thyme leaves). Meat spoilage (TV, PSY, MY, ENT, and LA), TBARS, CIELAB coordinates, metmyoglobin and the sensory characteristics of fresh lamb meat were analyzed on days 0, 7, 14 and 21. The presence of antioxidant compounds in the diet containing TL delayed (P<0.05) colour deterioration, lipid oxidation and bacterial counts, while at the same time imparting a better appearance to the fresh lamb meat. In general, this effect was more pronounced at the higher level of TL (7.5%). High Pearsons correlation coefficients were found between the sensory attributes, CIELAB coordinates and TBARS.

Microbial, physical–chemical and sensory spoilage during the refrigerated storage of cooked pork loin processed by the sous vide method

The aim was to study spoilage during the refrigerated storage of cooked pork loin processed by the sous vide method. Samples were packaged under vacuum into polyamide-polypropylene pouches, cooked at an oven temperature/time of 70°C/12h, chilled at 3°C and stored at 2°C for 0, 5 or 10 weeks. Microbial (psychrotrophs, lactic acid bacteria, Enterobacteriaceae, moulds and yeasts), physical-chemical (pH, water activity, TBARS, acidity, L(∗)a(∗)b(∗) colour, texture profile analysis and shear force) and sensory (appearance, odour, flavour, texture and acceptance) parameters were determined. The results showed that sensory spoilage preceded microbiological spoilage of sous vide pork loin. Counts bellow 1logcfu/g of psychrotrophs, anaerobic psychrotrophs, Enterobacteriaceae and lactic acid bacteria were detected in any control week, while moderate counts (2-3logcfu/g) of moulds and yeasts were found. Minor changes in water activity, lipid oxidation, CIELab colour, hardness, cohesiveness or gumminess were associated with spoilage of pork loin, only decreases of lactic acid, springiness and shear force were observed. The pork loin was unacceptable after 10 weeks. This loss of acceptance was mainly due to the deterioration of meaty flavour and odour, although the loss of appearance, juiciness and firmness also contributed. Moderate warmed-over and rancidity were detected. The sensory analysis was the most effective method for determining the shelf life of the sous vide pork-based dishes.

Modelling the yield and texture of comminuted pork products using color and temperature. Effect of fat/lean ratio and starch

Practices to control the processing of finely comminuted meat products are proposed. The objective was to test the practical value of both temperature and light reflection measurements made during emulsification as potential indicators of cooking losses and resulting gel texture in pork sausages emulsified within a wide range of temperatures and starch and fat levels. Prior to cooking, pork batters were chopped for different times to ensure final emulsion temperatures ranging from 5 to 50°C. The effects of the fat/lean ratio (0.25 and 0.67) and starch addition (0.8 and 3.2% w:w) on temperature and optical reflection were also investigated. The chopping increased the temperature and decreased the light reflection of fresh meat emulsion. There was no relevant loss of emulsifying capacity at emulsion temperature below 30°C and lightness values over 70 CIE units. The losses and textural parameters of cooked emulsions could be predicted by means of non-linear regression equations based on the temperature and color of the raw emulsion. The determination coefficients obtained ranged from 0.89 to 0.99. The prediction models needed to be fitted to each batter formulation, especially in the presence of reduced levels of gelation agents (meat protein and starch). Lightness was a better predictor than chromaticity, since it decreased constantly with chopping in the range of final emulsion temperatures studied (5-50°C). This confirms previous studies that lightness could be used for monitoring emulsion stability in meat batters.

Determination of Shelf Life of Sous Vide Salmon (Salmo Salard) Based on Sensory Attributes

Sous vide technology permits precooked dishes of high sensory and nutritional quality to be obtained with a longer shelf life than is possible using other cooking-cooling methods. Salmon portions (200 g; 0.5, w:w; greased with olive oil) were par-roasted (300 degrees C/3 min), cooked using sous vide technology (80 degrees C/43 min), and maintained in anaerobic conditions at 2 degrees C for 0, 4, 8, 12, 15, 18, 22, and 25 d. At each control day, Enterobacteriaceae counts were made and the attributes of sensory spoilage were determined (3 visual, 2 odor, 2 flavor, and 3 texture attributes) by a panel of trained judges. A loss of smell, taste, color, and juiciness was detected during storage, along with the appearance of off-odors and off-flavors. The shelf life of the sous vide salmon based on sensory analysis was established at 18 d.

Modification of Fatty Acid Composition in Meat Through Diet: Effect on Lipid Peroxidation and Relationship to Nutritional Quality – A Review

© 2012 Nieto and Ros, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Modification of Fatty Acid Composition in Meat Through Diet: Effect on Lipid Peroxidation and Relationship to Nutritional Quality – A Review

Biological Activities of Three Essential Oils of the Lamiaceae Family

Herbs and spices have been used since ancient times to improve the sensory characteristics of food, to act as preservatives and for their nutritional and healthy properties. Herbs and spices are generally recognized as safe (GRAS) and are excellent substitutes for chemical additives. Essential oils are mixtures of volatile compounds obtained, mainly by steam distillation, from medicinal and aromatic plants. They are an alternative to synthetic additives for the food industry, and they have gained attention as potential sources for natural food preservatives due to the growing interest in the development of safe, effective, natural food preservation. Lamiaceae is one of the most important families in the production of essential oils with antioxidants and antimicrobial properties. Aromatic plants are rich in essential oils and are mainly found in the Mediterranean region, where the production of such oils is a profitable source of ecological and economic development. The use of essential oils with antimicrobial and antioxidant properties to increase the shelf life of food is a promising technology, and the essential oils of the Lamiaceae family, such as rosemary, thyme, and sage, have been extensively studied with respect to their use as food preservatives. Regarding the new applications of essential oils, this review gives an overview of the current knowledge and recent trends in the use of these oils from aromatic plants as antimicrobials and antioxidants in foods, as well as their biological activities, future potential, and challenges.

Hydroxytyrosol extracts, olive oil and walnuts as functional components in chicken sausages

BACKGROUND Olive oil, hydroxytyrosol and walnut can be considered ideal Mediterranean ingredients for their high polyphenolic content and healthy properties. Three extracts of hydroxytyrosol obtained using different extraction processes (HXT 1, 2, 3) (50 ppm) were evaluated for use as antioxidants in eight different chicken sausage formulas enriched in polyunsaturated fatty acids (2.5 g 100 g-1 walnut) or using extra virgin olive oil (20 g 100 g-1 ) as fat replacer. Lipid and protein oxidation, colour, emulsion stability, and the microstructure of the resulting chicken sausages were investigated and a sensory analysis was carried out. RESULTS The sausages with HXT extracts were found to decrease lipid oxidation and to lead to the loss of thiol groups compared with control sausages. Emulsion stability (capacity to hold water and fat) was greater in the sausages containing olive oil and walnut than in control sausages. In contrast, the HXT extracts produced high emulsion instability (increasing cooking losses). Sensory analysis suggested that two of the HXT extracts studied (HXT2 and HXT3 ) were unacceptable, while the acceptability of the other was similar to that of the control products. Sausages incorporating HXT showed different structures than control samples or sausages with olive oil, related to the composition of the emulsion. CONCLUSION These results suggest the possibility of replacing animal fat by olive oil and walnut in order to produce healthy meat products.

Antioxidant and Antimicrobial Properties of Rosemary (Rosmarinus officinalis, L.): A Review

Nowadays, there is an interest in the consumption of food without synthetic additives and rather with the use of natural preservatives. In this regard, natural extracts of the Lamiaceae family, such as rosemary, have been studied because of its bioactive properties. Several studies have reported that rosemary extracts show biological bioactivities such as hepatoprotective, antifungal, insecticide, antioxidant and antibacterial. It is well known that the biological properties in rosemary are mainly due to phenolic compounds. However, it is essential to take into account that these biological properties depend on different aspects. Their use in foods is limited because of their odour, colour and taste. For that reason, commercial methods have been developed for the preparation of odourless and colourless antioxidant compounds from rosemary. Owing to the new applications of natural extracts in preservatives, this review gives a view on the use of natural extract from rosemary in foods and its effect on preservative activities. Specifically, the relationship between the structure and activity (antimicrobial and antioxidant) of the active components in rosemary are being reviewed.

Hydroxytyrosol: Health Benefits and Use as Functional Ingredient in Meat

Hydroxytyrosol (HXT) is a phenolic compound drawn from the olive tree and its leaves as a by-product obtained from the manufacturing of olive oil. It is considered the most powerful antioxidant compound after gallic acid and one of the most powerful antioxidant compounds between phenolic compounds from olive tree followed by oleuropein, caffeic and tyrosol. Due to its molecular structure, its regular consumption has several beneficial effects such as antioxidant, anti-inflammatory, anticancer, and as a protector of skin and eyes, etc. For these reasons, the use of HXT extract is a good strategy for use in meat products to replace synthetics additives. However, this extract has a strong odour and flavour, so it is necessary to previously treat this compound in order to not alter the organoleptic quality of the meat product when is added as ingredient. The present review exposes the health benefits provided by HXT consumption and the latest research about its use on meat. In addition, new trends about the application of HXT in the list of ingredients of healthier meat products will be discussed.