EVALUATION OF DUCKLING BREAST MEAT SUBJECTED TO DIFFERENT METHODS OF FURTHER PROCESSING AND COOKING

Breast fillets (128 total) deboned from commercially processed 7-week-old Pekin ducklings were subjected to one of four tenderization treatments: control, mechanically tenderized, marinated, or tenderized and marinated, and one of two cooking methods, oven-baked or gourmet-cooked. Treatments were evaluated for cooked yield and tenderness. Mechanical tenderization resulted in the lowest cooked yield, 60.0%, followed by the control, 64.5%. Mechanical tenderization and the control treatment were not significantly different for shear, with an average of 7.0 kg shear/g sample. Marination, with or without mechanical tenderization, resulted in signficantly greater cooked yield, 72.6 and 72.9 % respectively, and more tender meat, 4.9 and 5.1 kg shear/g meat respectively. Oven baking resulted in a signficantly greater cooked yield than gourmet cooking. Results indicate that marination, with or without mechanical tenderization, can significantly improve the cooked yield and tenderness of duckling breast fillets.     

USE OF IRRADIATION TO KILL ENTERIC PATHOGENS ON MEAT AND POULTRY1

Ionizing radiation can be an effective step in a HACCP program to kill enteric pathogens associated with meat and poultry products. The populations of most common enteric pathogens such as Campylobacter jejuni, Escherichia coli O157:H7, Staphylococcus aureus, Salmonella spp., Listeria monocytogenes, and Aeromonas hydrophila can be significantly decreased or eliminated by low-dose (< 3.0 kGy) treatments with ionizing radiation. Only the enteric viruses and the endospores of the genera Clostridium and Bacillus are highly resistant to ionizing radiation, and even these are affected to some degree. Temperature effects must be carefully considered, as reduced irradiation temperatures not only result in fewer adverse changes in the sensorial properties of meat and poultry products, but they also may demand that greater radiation doses be used to inactivate the foodborne pathogen. Equations have been developed that predict the effects of low-dose ionizing radiation treatments on several enteric pathogens associated with meat and poultry. In some cases substrate-specific differences in radiation resistance have been found. Irradiation in combination with vacuum packaging or modified-atmosphere packaging has increased both safety and shelf-life for some types of refrigerated products. High-dose irradiation treatments of enzyme-inactivated meat or poultry products in vacuo at subfreezing temperatures can be used to prepare sterile, shelf-stable products with excellent sensorial properties. Such products have been used extensively by military organizations, NASA during space flights, yachtsman, and hospitals. Contemporary research will be reviewed.     

TENDERNESS ANALYSIS AND CONSUMER SENSORY EVALUATION OF OSTRICH MEAT FROM DIFFERENT MUSCLES AND DIFFERENT AGING TIMES1

Six ostrich carcasses were split and aged for 1 h, 1 day, or 1 week, roasted to 75 C and evaluated for tenderness and sensory attributes. Shear values for aged ostrich meat were 10.1, 10.0, 10.0, and 14.1 kg/g for 1 h, 1 day, 1 week, and the beef control, respectively. The most tender ostrich muscles identified were: M. iliofibularis, M. iliofemoralis, and M. oburatorius lateralis. Tenderness was affected by fiber orientation of the meat after slicing. Shear values were higher (p<0.05) for the longitudinal fiber orientation (11.5 kg/g) compared with the transverse fiber orientation (7.4 kg/g). A 9–point hedonic scale and a consumer sensory panel were used to evaluate tenderness, flavor, and overall acceptance of selected cuts. Ostrich meat aged for 1 week provided higher (p<0.05) liking scores for flavor compared with lesser aged ostrich or the beef control. This study suggests that prepared ostrich meat provides a good alternative compared with a similar beef product.     

THE EPIDEMIOLOGY AND COSTS OF DISEASES OF PUBLIC HEALTH SIGNIFICANCE, IN RELATION TO MEAT AND MEAT PRODUCTS

Meat and meat products are important vehicles of foodborne illness outbreaks in European countries. Salmonellas were the most commonly reported aetiology of infection, although the relative importance of other agents varied. The factors contributing to the increase in food poisoning and salmonellosis in England and Wales related both to foods eaten and their preparation. The implication of foods of animal origin as principle vehicles of infection was strengthened by reports associating these foods with outbreaks of human illness, and reports of salmonella infection in animals and poultry. The current increase in salmonella infection associated with poultry products suggests that reducing infection in, or contamination of poultry could significantly decrease human illness.
The problem of human salmonellosis is multi-factorial. Trends are driven by both intrinsic factors relating to the microbiological quality of the food and standards of preparation, and extrinsic factors, such as ambient temperature, which amplify the intrinsic effects. Many of these factors may be amenable to preventive activities, including programs to reduce infection in animals and poultry and programs to educate the consumer in safe food handling.
The costs of human salmonella infection in England and Wales were estimated to be between £231 million and £331 million in 1988 of which £143 million to £205 million may have been associated with meatborne infection. Reductions in human illness, as modelled by irradiation of poultry meat, could give substantial economic gains.     

USE OF PROTEASES TO ENHANCE SOLUBILIZATION OF RICE BRAN PROTEINS1

Extraction yields of rice bran protein increased with the use of protease as the degree of hydrolysis (DH) increased, reaching 92% at a 10% DH value. Extraction of rice bran proteins was also carried out using limited proteolysis to 2% DH with Na₂SO₃ and/or SDS (0.2 mmol/g protein). Protein recovery increased from 74% to 80, 81, and 84% in the presence of Na₂SO₃, SDS and both, respectively. The presence of Na₂SO₃ or SDS yielded protein hydrolysates of a broader range of medium sized peptides with 78% of these protein hydrolysates having M_r of 11–68 kDa. Accordingly, use of proteases can be an efficient method for recovering high quality, value-added ingredients from the proteins of rice bran for food use.     

EVALUATION OF MEAT PRODUCTS BY FLUORESCENCE MICROSCOPY

Various procedures, utilizing dyes which fluoresce when exposed to UV light, were tested as a means to study the morphology of meat products. The procedures are simple and rapid and allow specific visualization of components such as fat (with Nile blue A), protein (with acridine orange) and microorganisms (with acridine orange). The methods are applicable to both critical studies of morphology and in rapid evaluation for industrial quality control.     

ENGINEERING ASSESSMENT AND CRITIQUE OF INSTRUMENTS USED FOR MEAT TENDERNESS EVALUATION*

A review of the methods used to measure meat texture indicates considerable confusion in terminology, test conditions, and interpretation of the readings that makes evaluation of the results a complex task. Standardization of the methods appears premature and until this is accomplished, the applied methodology must be reported fully. Errors due to instrument design can no longer be accepted since modern instruments that overcome this are readily available. A common error in terminology or interpretation is the use of the term shear to describe the rupture imposed on meat samples in popular tests. It is shown that meat generally ruptures in tension which is also the case during mastication; this explains why empirical measurements often relate to sensory readings. It is concluded that there is room for improvement in existing methods, particularly in the interpretation of the results using common sense, close observation and theoretical analysis.     

ATTACHMENT OF CERTAIN BACTERIAL STRAINS TO CHICKEN AND BEEF MEAT

The attachment of bacteria to chicken and beef meat with and without fascia was studied. It was found that bacteria attach readily to the meat surfaces. The kinetics of attachment depend on the bacterial strain, as well as on the meat surface. Of the bacteria tested, Pseudomonas EBT/2/143 attached most readily to all meat surfaces examined. Chicken breast with fascia was the best surface for attachment.
A study was also made of the effects of storage on the multiplication of the attached bacteria and the feasibility of removing them. A high level of Salmonella infantis was found in comparison to the other bacteria after 24 h of storage at 20°C.
More investigations are needed to find out whether other serotypes of salmonellae will multiply to similar levels on these surfaces.
After micro-colonies began to form, the newly generated bacteria were easy to remove. The hygienic consequence of this phenomenon is discussed.     

近红外光谱技术在评定肉类品质上的应用

本文介绍了近红外光谱技术的原理及其在评定肉类品质上的应用和发展前景,并简要介绍了应用近红外光谱技术在评定牛肉品质上应用实例。     

THE RELATIONSHIP OF FATTY ACID COMPOSITION AND CARCASS CHARACTERISTICS TO MEAT FLAVOR IN LAMB1

The relationship of 20 fatty acids and carcass quality characteristics to meat flavor in lamb was studied. Subcutaneous fat samples obtained from 64 lamb carcasses were analyzed for fatty acid composition. A taste panel evaluated flavor of a ground lean-fat mixture of meat. Flavor was most highly correlated with amounts of fatty acids 18:1 and 18:3 (r =—0.33 and r = 0.33, respectively). The remaining fatty acids were not associated with flavor. Quality grade, carcass weight, fat softness, maturity and fat color were not associated with lamb flavor. Carcass softness was not associated with quality grades. Greater quantities of 17:0, 18:1, and 18:2 were associated with increased carcass fatness.     

PRODUCT DEVELOPMENT AND NUTRACEUTICAL ANALYSIS TO ENHANCE THE VALUE OF DRIED FRUIT

ABSTRACT

Value‐added fruit products suitable for production by small‐scale farmers and processors were developed and evaluated. Apples, blueberries, peaches and strawberries from local growers were processed into a dried fruit product. The total phenolics, total anthocyanins and oxygen radical absorbing capacity (ORAC) were determined. Drying the fruit concentrated total phenolics, total anthocyanins and ORAC levels as compared to fresh fruit. The nutraceutical components of the blueberries, peaches and strawberries of the local dried fruit were higher than those of commercial dried fruit purchased at a natural food store. The dried fruit from both the local and commercial fruits was used to create a fruit pie filling for consumer evaluation. Consumer acceptance of fruit pie filling from dried fruit grown locally and dried commercial fruits was evaluated using a 9‐point verbal hedonic scale and a 5‐point Just About Right scale. In terms of consumer evaluation, the pie fillings made from local dried fruits were either better or at parity with those from commercial products. In addition to the nutraceutical benefits, the pie fillings were consumer acceptable products that could represent an avenue for small‐scale farmers to add value to surplus fruit.

PRACTICAL APPLICATIONS

Complete utilization of fruit crops is a key component to the success of small farm operations. Excess fruit crops can be dried (or processed in other manners) and used to create many value‐added products. Increased consumer awareness of healthy food products provides a niche market for these fruit products. In this research, the nutraceutical benefits of fresh and dried apples, blueberries, peaches and strawberries were investigated and the consumer overall acceptance of a pie filling produced from these dried fruit was shown.

     

TEXTURE AND COLOUR CHANGES IN MEAT DURING COOKING RELATED TO THERMAL DENATURATION OF MUSCLE PROTEINS1

Differential scanning calorimetry was used to select temperatures that diferentiated between thermal denaturation of the three major structural protein species in bovine muscle: myosin, collagen and actin. Samples of m. semimembranosus, m. semitendinosus and m. psoas major were heated to those different temperatures and evaluated sensorially. Three groups of sensory properties were needed to describe the main texture changes observed in the meat: 1. Firmness 2. Fiber cohesivity, bite-off force, residual bolus 3. Juiciness Firmness increased with thermal denaturation of the myofibrillar proteins (myosin; 40-60d?C and actin; 66-73d?C). Fiber cohesivity etc. decreased with collagen denaturation (56-62d?C). Reduction in juiciness was primarily associated with actin denaturation, while cooking loss increased over the whole temperature range. The property “total chewing work”, a composite of the first two texture groups mentioned, yielded like the judges' “total texture preference”, optimal texture in the 60-67d?C temperature region, implying denatured myosin and collagen but native actin. This meat was light pink-gray in colour, while the cooking juice released was dark red.     

COLLAGEN CHARACTERISTICS AND MEAT TEXTURE OF PIGS EXPOSED TO DIFFERENT LEVELS OF PHYSICAL ACTIVITY

Intramuscular collagen and meat texture were measured in 23 female and 23 entire male pigs, subjected to one of three treatments: individual housing in pens of 2.5 m² (confined; C), individual housing and regular treadmill training (trained; T) and group housing equal to 0.9 m²/animal (free; F).
Treatment T tended (P = 0.13) to increase the activity of citrate synthase (CS) in M. biceps femoris (BF) from female pigs. Moreover, the heat stability of collagen and the mechanical resistance to 60 and 80% compression were increased (P<0.03) in BF from female pigs in treatments T and F as compared to C. In BF from male pigs, treatment T decreased (P = 0.03) the heat stability of collagen when compared to C and F. Sensory tenderness was not affected (P>0.05) by physical activity, however. In BF from female pigs, CS activity, collagen content and resistance to compression were lower (P<0.01) than in male pigs. In M. longissimus thoracis et lumborum, there was no effect of either physical activity or sex. Depending on muscle type and sex, physical activity affects meat texture.