M.N. O’Grady

Addition of tea catechins and vitamin C on sensory evaluation, colour and lipid stability during chilled storage in cooked or raw beef and chicken patties

The effects of addition of tea catechins (TC) and vitamin C (VC) on sensory evaluation, colour and lipid stability in cooked or raw beef and chicken meat patties during refrigerated storage were studied. Fresh beef striploin and chicken breast muscles were minced, following removal of external fat and connective tissue. Following mincing, beef and chicken were assigned to one of the following five treatments: control (meat treated with no antioxidant); TC200, meat plus 200 mg TC/kg muscle; TC400, meat plus 400 mg TC/kg muscle; VC200, meat plus 200 mg VC/kg muscle, VC400, meat plus 400 mg VC/kg muscle. Sodium chloride (1%) was added to all samples. Patties (125 g portions), formed from the above-treated minced meat, were oven cooked, cooled, and packaged in 30% CO(2):70% N(2). Fresh raw beef and chicken patties were packaged in 80% O(2):20% CO(2). All samples were stored for up to 7 days under fluorescent lighting at 4 °C. Sensory parameters (colour, flavour, taste, tenderness and overall acceptability) were evaluated on cooked beef and chicken patties after 1, 3 and 6 days of storage. Surface colour (Hunter L, a and b values), and lipid oxidation (2-thiobarbituric acid reactive substances) were measured on days 1, 3 and 6 of storage for cooked meats and on days 2 and 7 for raw beef and chicken. Tea catechins addition (200 or 400 mg/kg) to minced meat caused (P<0.05) discolouration in cooked beef and chicken meat patties and significantly reduced (P<0.001) lipid oxidation in cooked or raw beef patties compared to the control. Beef, either raw or cooked, was more susceptible (P<0.01) to oxidation compared to chicken. Raw meat stored in high oxygen conditions was more susceptible to lipid oxidation than cooked meat stored in anaerobic conditions. Tea catechins treatments (TC200 and TC400) inhibited (P<0.05) lipid oxidation in raw beef to a greater extent than vitamin C treatments (VC200 and VC400). These results indicate that tea catechins are potent natural antioxidants and exhibit greater antioxidant efficacy compared to vitamin C.

Effect of lutein, sesamol, ellagic acid and olive leaf extract on the quality and shelf-life stability of packaged raw minced beef patties

The effects of lutein (100 and 200 microg/g muscle), sesamol (250 and 500 microg/g muscle), ellagic acid (300 and 600 microg/g muscle) and olive leaf extract (100 and 200 microg/g muscle) on total viable counts (TVCs), lipid oxidation (thiobarbituric acid-reactive substances, TBARS), colour, oxymyoglobin oxidation, pH, water-holding capacity (WHC), sensorial properties of raw beef patties (M. longissimus thoracis et lumborum) stored in modified atmosphere packs (80% O(2):20% CO(2)) (MAP) aerobically at 4 degrees C for up to 8 and 12 days, respectively, were examined. All the nutraceuticals reduced (P<0.001) TVCs. The addition of sesamol, ellagic acid and olive leaf extract reduced (P<0.001) TBARS in raw beef patties in both packaging systems. Sesamol addition to beef resulted in lower (P<0.01) a* redness values and increased oxymyoglobin oxidation. Conversely, lutein and olive leaf extract reduced (P<0.001) oxymyoglobin oxidation relative to the control. The graded addition of ellagic acid and olive leaf extract improved (P<0.001) WHC.

The effect of lutein, sesamol, ellagic acid and olive leaf extract on lipid oxidation and oxymyoglobin oxidation in bovine and porcine muscle model systems

The effect of lutein (100, 200, 300μg/ml), sesamol (500, 1000, 2000μg/ml), ellagic acid (300, 600, 900μg/ml) and olive leaf extract (100, 200, 300μg/ml) on oxymyoglobin oxidation and lipid oxidation in bovine and porcine muscle model systems (25% M. longissimus thoracis et lumborum homogenates) was examined. Radical scavenging activity, using the DPPH assay, and iron-chelating activities of lutein, sesamol, ellagic acid and olive leaf extract were assessed at concentrations ranging from 200 to 1000ppm. The radical scavenging activity was of the order: ellagic acid>sesamol>olive leaf extract>lutein. None of the natural antioxidants examined exhibited iron chelating activity. Following induced lipid oxidation (FeCl(3)/sodium ascorbate addition), lipid oxidation and oxymyoglobin oxidation were measured after 24h at 4°C. In bovine and porcine muscle model systems, lipid oxidation decreased (P<0.001) following addition of each of the natural antioxidants relative to the control and antioxidant potency followed the order: sesamol>ellagic acid>olive leaf extract>lutein. Ellagic acid and olive leaf extract decreased oxymyoglobin oxidation (P<0.001) while sesamol increased oxymyoglobin oxidation in both systems. The natural antioxidants examined may have applications in the development of nutritional enhanced meat products with enhanced shelf-life characteristics.

Smart Packaging Technologies and Their Application in Conventional Meat Packaging Systems

Preservative packaging of meat and meat products should maintain acceptable appearance, odour and flavour and should delay the onset of microbial spoilage. Typically fresh red meats are placed on trays and over-wrapped with an oxygen permeable film or alternatively, meats are stored in modified atmosphere packages (MAP) containing high levels of oxygen and carbon dioxide (80% O2:20% CO2) (Georgala & Davidson, 1970). Cooked meats are usually stored in 70% N2:30% CO2 (Smiddy, Papkovsky, & Kerry, 2002). The function of oxygen in MAP is to maintain acceptable fresh meat colour and carbon dioxide inhibits the growth of spoilage bacteria (Seideman & Durland, 1984). Nitrogen is used as an inert filler gas either to reduce the proportions of the other gases or to maintain the pack shape (Bell & Bourke, 1996). High oxygen levels promote the oxidation of muscle lipids over time with deleterious effects on fresh meat colour and quality (O’Grady et al., 1998). In cooked meat products (e.g. cured ham) low residual levels of oxygen promote pigment denaturation which imposes a dull greyness to the meat surface (Moller, Jensen, Olsen, Skibsted, & Bertelsen, 2000). Commercially, this problem is overcome with the use of an oxygen scavenger. Oxygen scavengers are examples of entities described as ‘active packaging components’. Smart packaging is a broad term encompassing a range of new packaging concepts, most of which can be placed in one of the two principle categories: active packaging and intelligent packaging. Active packaging refers to the incorporation of certain additives into packaging systems (loose within the pack, attached to the inside of packaging material or incorporated into the packaging material) with the aim of maintaining or extending product quality and shelf life. Packaging may be termed active when it performs some desired role in food preservation other than providing an inert barrier to external conditions (Hutton, 2003). Active packaging has been defined as packaging which ‘changes the condition of the packed food to extend shelf-life or to improve safety or sensory properties, while maintaining the

Influence of Green Seaweed (Ulva rigida) Supplementation on the Quality and Shelf Life of Atlantic Salmon Fillets

ABSTRACT Supplementation of salmon (Salmo salar) diets with Ulva rigida (UR; 0, 5, 10, and 15% UR) or synthetic astaxanthin (positive control, PC) for 19-weeks preslaughter on quality indices of fresh (raw) salmon fillets was examined. Susceptibility of salmon fillets/homogenates to oxidative stress conditions (cooking/iron-ascorbate induced oxidation) was also measured. In salmon fillets stored in modified atmosphere packs (MAP; 60% N2:40% CO2) for up to 15 days at 4ºC, U. rigida increased surface “−a*” greenness and “b*” yellowness values in a dose-dependent manner resulting in a final yellow/orange flesh color. Proximate composition, pH, and lipid oxidation (fresh, cooked, and fillet homogenates) were unaffected by dietary addition of U. rigida. On Day 12, 5% UR psychrotrophic bacterial growth was lower than controls. Salmon fed 5% UR did not influence “eating quality” sensory descriptors (texture, odor, oxidation flavor, and overall acceptability) in cooked salmon fillets compared to 0% UR. Higher levels of dietary U. rigida (10 and 15% UR) were negatively correlated with color and overall acceptability descriptors. Results indicated that dietary U. rigida, at a level of 5%, may prove to be a functional ingredient in salmon feed to enhance salmon fillet quality.

The effect of non-meat ingredients on quality parameters in meat and poultry.

Abstract: A number of factors affect the quality of meat and poultry. Colour is an important quality attribute influencing the consumer’s purchase decision. The oxidation of muscle lipids ultimately leads to off-odours and flavours. The eating quality of meat is affected by tenderness, texture, juiciness and flavour. Microbial contamination and spoilage also have a negative impact on the sensory quality of meat and poultry. This chapter examines the use of non-meat ingredients (sodium chloride (salt), phosphates, lactates, carrageenans, whey protein, soya protein, starch and enzymes) in comminuted and whole cuts of meat and poultry. The influence of such ingredients on the quality and shelf life parameters of meat and poultry was evaluated.