EFFECT OF STORAGE TEMPERATURE ON MEAT QUALITY OF MUSCLE WITH DIFFERENT FIBER TYPE COMPOSITION FROM KOREAN NATIVE CATTLE (HANWOO)

Three kinds of Hanwoo (Korean native cattle) muscles (Loin, strip loin and inside round) were obtained from a local farm and then divided into two storage temperatures (0 and 5C), respectively. In meat color, redness ( a *) was significantly higher in 5C storage samples compared with 0C storage samples in all muscle samples after 7 days of storage. Loin had significantly lower purge loss than other muscle samples, whereas inside round was significantly higher in purge loss. Strip loin showed lower shear force values compared with those of other muscle samples. 5C storage samples had significantly higher thiobarbituric acid reactive substances value than 0C storage samples in all muscle samples. In sensory evaluation, overall acceptability was significantly higher at 14 or 21 days of storage in all muscle samples, and 5C storage samples showed higher overall acceptability compared with 0C storage samples.

PRACTICAL APPLICATIONS

This result will obtain information to help understand the meat quality in Hanwoo for the foreign scientists. The results of the present study showed that meat qualities of Hanwoo were much higher in 5C storage sample compared with 0C samples in all muscle samples until 35 days of storage, and loin sample showed higher sensory score than strip loin and inside round samples.     

TENDERNESS, pH AND ACCEPTABILITY OF MEAT FROM PODOLIAN AND LIMOUSINE × PODOLIAN YOUNG BULLS

The relationships between meat pH, sensory tenderness and acceptability for Podolian (P) and Limousine  ×  Podolian (LP) beef were investigated. Negative linear relationships between pH measured at each of 1, 24 and 48 h post mortem and sensory tenderness were found at 2 ( P <  0.001) and 7 days of ageing ( P <  0.05). At 7 days of ageing, sensory tenderness was higher ( P <  0.001) than that at 2 days of ageing. LP beef showed higher sensory tenderness ( P <  0.001) than P. The regression between perceived tenderness and acceptability was separately calculated for LP and P beef. Both were significant ( P <  0.01 and P <  0.001, respectively). In addition, a significant difference was observed between the two regression coefficients ( P <  0.05), indicating that the two variables were more associated for P than LP beef.

PRACTICAL APPLICATIONS

Meat acceptability is obviously related to tenderness. More interestingly, other factors (e.g., familiarity, age, etc.) can affect product acceptability. In fact, the same product can be perceived by some consumers as being tough, whereas it can be considered tender by others, corresponding to low and high levels of acceptability, respectively. Therefore, along with treatments aimed to increase tenderness (e.g., ageing), information about the product, age and familiarity of consumers, etc., can increase the acceptability of meats, which are less tender because of their intrinsic properties.     

COMPARISON OF SALAMI SAUSAGE PRODUCED WITH AND WITHOUT ADDITION OF SODIUM NITRITE AND SODIUM NITRATE

A pilot plant production of salami dry sausage with and without the addition of nitrite was carried out. The microbiological, rheological and organoleptic properties of the products were investigated during the fermentation process and after storing the products at 20 °C for 3 months. Results of the microbiological investigation indicate that the fermentation and ripening of the sausage would take a normal course without the addition of nitrite, glucono-delta-lactone (GDL) or starter culture. In a triangle test performed at the end of the ripening period, the taste panel was unable to distinguish between products with and without nitrite. After 3 months storage a significant difference was found between products with and without the addition of nitrite, and the nitrite-cured products were given the best score. In series in which GDL or starter culture was added, no significant differences in organoleptic quality were found even after storage for 3 months.     

DETECTION AND CHARACTERIZATION OF VEROTOXIN-PRODUCING ESCHERICHIA COLI (VTEC) ISOLATED FROM BUFFALO MEAT

The emergence of Verotoxin‐producing Escherichia coli (VTEC) as zoonotic foodborne pathogens in recent years has become a public health concern because of its life threatening human diseases. In the present investigation, out of 87 strains of E. coli, 22 (25%) belonging to 13 different serotypes isolated from raw buffalo meat and its products were found to be verotoxic as tested by Vero cell cytotoxic assay. Serotype O26 followed by O153 and O157 were the predominant VTEC. All the VTEC strains were found positive for vt genes by polymerase chain reaction (PCR). Among the vt genotypes, vt₂(77%) was most predominant followed by vt₁(14%) and both vt₁and vt₂(9%). Production of enterohaemolysin on washed sheep blood agar supplemented with CaCl₂ showed 19 (86%) VTEC strains to be positive. Presence of VTEC in cooked buffalo meat products, namely shami kabab and kabab, appears to be a matter of concern and a potential threat to public health. VTEC detection by different methods suggests that PCR can be useful to evaluate the distribution of virulence genes (vt₁or vt₂or both) in E. coli isolates from buffalo meat and its products.     

THE EFFECT OF CARCASS ELECTRICAL STIMULATION ON MEAT OBTAINED FROM BOS INDICUS AND BOS TAURUS CATTLE1

Sides of 30 carcasses obtained from steers of Hereford and Angus (HA), Braham (Br) or Sahiwal (Sh) crossbreds were electrically stimulated (ES) by high voltage or remained as controls (CN). Longissimus muscle at the 12th rib of carcasses from the Br and Sh crossbreds was darker (P < 0.05) in color and possessed greater (P < 0.05) degrees of dark coarse band formation than muscle from the HA crossbreds. Broiled steaks from carcasses of Br and Sh crossbreds were less tender than steaks from HA. Electrical stimulation markedly improved (P < 0.05) dark coarse band formation, color and tenderness of steaks within the Bos indicus breed groups. Improved tenderness was associated with better (P < 0.05) sensory panel scores for ease of fragmentation of the myofibrillar portion and less (P < 0.05) connective tissue.     

SHELF LIFE OF MEAT FROM PODOLIAN YOUNG BULLS IN RELATION TO THE AGING METHOD

ABSTRACT

In order to achieve an adequate level of tenderness while reducing chilling and technological losses, the effect of two aging methods (on the carcass or under vacuum packaging) on the shelf life (5‐day retail display) of meat from eight Podolian young bulls (16–18 months old) was assessed. Most of the recorded variables were not affected by the interaction aging method × time of display (P > 0.05). These results indicate that the shelf life of meat from Podolian cattle was not influenced by the aging method. In both aging methods, redness a* increased after 1 day of display and subsequently decreased (P < 0.001). Lipid oxidation and total aerobic mesophilic count increased significantly during retail display (P < 0.001). We concluded that vacuum packaging may be conveniently used for the maturation of primal cuts from Podolian carcasses to save energy and space, and prevent chilling and technological losses.

PRACTICAL APPLICATIONS

The aging under vacuum of individual bovine primal cuts can save energy and space as well as prevent chilling and technological losses generally occurring when meat is aged on carcass. This method had no negative effects on meat shelf life. Thus, it may be conveniently used to apply sufficiently extended maturation periods to the meat, which are needed to increase tenderness to a level, which is not prejudicial to product acceptability.

     

羟丙基和磷酸酯化对不同玉米杂交种淀粉糊化特性的影响

采用了实验室方法提取了高直链、糯性和普通玉米杂交种的淀粉，并分别进行了羟丙基化和磷酸酯化反应。采用快速粘度分析仪（RVA）和差示扫描量热仪（DSC）分别分析了淀粉的糊化和热力学性质。结果表明：羟丙基化和磷酸酯化反应都不同程度地降低了所有淀粉的热焓值和糊化温度，缩短了出峰时间，增加了峰值粘度。二者相比，羟丙基化更显著地降低了原淀粉的糊化温度和热焓值，缩短了出峰时间；而磷酸酯化则更明显地提高了原淀粉的峰值粘度和终粘度．     

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.     

CHANGES DURING FERMENTATION AND PROPERTIES OF SOM-FUG PRODUCED FROM DIFFERENT MARINE FISH

ABSTRACT

Microbiological, chemical and physical changes of Som‐fug produced from six marine fish during fermentation were monitored. During the fermentation (0–72 h) at 30C, the increase in lactic acid bacteria (LAB) count and total acidity (TA) with the concomitant decrease in pH was observed. After the fermentation was completed, Som‐fug samples contained 1.5–7.9 × 10⁹ cfu/g LAB count and TA ranging from 2.00 to 2.28% with the pH range of 4.53–4.60. Trimethylamine N‐oxide content decreased, whereas trimethylamine content increased throughout the fermentation (P < 0.05). Proteolysis of Som‐fug proteins and lipid oxidation occurred during fermentation. As the fermentation proceeded, hardness, adhesiveness, springiness and cohesiveness of all samples increased, and L*, a*and b*values also increased (P < 0.05). Generally, Som‐fug produced from bigeye snapper showed a greater acceptability than those produced from other species. However, its acceptability was slightly lower than a commercial Som‐fug produced from freshwater fish (P < 0.05).

PRACTICAL APPLICATIONS

This research indicates that some marine fish can be used as the raw material for Som‐fug production with the quality almost comparable to those prepared from fresh water fish, which are commercially availalble. Therefore, the improvement of process for Som‐fug production from marine fish should be further conducted to obtain the better quality and higher acceptability. As a consequence, Som‐fug from marine fish with the high nutritive value can become a novel product for the consumers.

     

FATTY ACIDS AND MEAT CHARACTERISTICS OF DIFFERENT BIOLOGICAL TYPES OF BEEF CATTLE DEVELOPED UNDER A MANAGEMENT-INTENSIVE GRAZING SYSTEM

ABSTRACT

Beef steers representing four biological types were evaluated for fatty acid profiles and meat characteristics in muscle tissue developed on grazed forages. Biological types included six large‐framed, late maturing, nine medium‐framed, late maturing, nine medium‐framed, intermediate maturing, and nine medium‐framed, early maturing steers. Longissimus dorsi muscles were removed and frozen after 7 days of dry aging. Tenderness and cook loss were similar between biological types. Significant differences (P < 0.05) in fatty acid profiles were found between biological types. The medium‐framed, early maturing animals scored highest (P < 0.05) in marbling, had the highest (P < 0.05) concentration of total n‐3 fatty acids, and had the lowest n–6/n–3 ratio at 1.03:1. All biological types had a mean n–6/n–3 ratio well below the recommended <4:1 for human cardiovascular health. Under this dietary management system, medium‐framed, early maturing beef steers should be considered for producing grass‐fed beef based on both carcass merit and fatty acid composition.

PRACTICAL APPLICATIONS

Beef cattle that reach physiological maturity (i.e. puberty) earlier than their contemporaries should be selected for the production of grassfed beef if fully developed on forages. Those animals have the ability to deposit fat earlier than their later‐maturing contemporaries. Additionally, medium‐framed beef animals should be selected over larger‐framed animals as skeletal frame does not contribute to meat quality but requires more nutritional input for growth and maintenance. This ability to deposit fat exclusively on forage nutrients, without energy or protein supplementation, should be exploited when developing grassfed beef. Fat deposition, particularly intramuscularly (IM), contributes positively to meat quality. Fatty acids, especially the ratio of n‐6/n‐3, are optimized when beef animals have been fully developed on nutrient‐dense forages. Forages must be managed in such a way to capture those nutrients for animal intake and protect the plants for regrowth in a pasture setting.     

INFLUENCE OF HEATING END-POINT TEMPERATURE ON VOLATILES FROM POULTRY MEAT - A REVIEW

During heating of muscle foods, numerous volatile flavor components are generated. Both the identity and quantity of these volatiles are influenced by cooking end-point temperature (EPT) and post-cooking storage. Methods for assessing flavor volatiles include sensory tests and gas chromatographic (GC) methods. Static headspace GC techniques either with a packed or capillary column have been used to determine the volatiles individually and they are simpler in operation compared to sensory tests. High correlations between EPTs and several compounds in heated chicken breast and leg meat patties have been obtained. Samples prepared in model systems are more uniform in EPTs as compared to processed products. Good resolution and reproducibility in the analysis of volatiles from chicken meat have been reported by using a dynamic headspace-capillary column approach. More than one half of all compounds increased linearly or quadratically as EPT increased. Controlling the heating EPT is important in ensuring the quality and stability of precooked poultry.     

INFLUENCE OF DIFFERENT FACTORS ON ACTIVITY AND STABILITY OF ß-GALACTOSIDASE FROM LACTOBACILLUS ACIDOPHILUS1

Eight Lactobacillus acidophilus strains were tested for β-galactosidase activity. The results show that β-galactosidase is an inducible enzyme in this organism. Wide variations in enzyme properties of the strains were observed. The temperature and pH optima of the enzymes were 40–45C and 6.5–7.0, respectively. At 0.1 mM concentration, the enzyme activity in strain 4495 was slightly stimulated by 2-mercaptoethanol, partially inhibited by EDTA but remained more or less unaffected with thiomersal and ascorbic acid. In contrast, all the modulators completely inhibited the enzyme activity in strain 301. The enzyme in strain 301 was stable for 80 min at 50C, whereas the activity in strain 4495 was completely lost in 40 min. However, the enzyme was stable over a pH range of 5.8–8.0 and up to 60 days at 4 ± 1C in both strains. The K_m values for β-galactosidase from both the strains were same, whereas V_max for the enzyme from strain 301 was about 2-fold higher than that of strain 4495.