Sixteen beef carcasses were harvested to determine the effect of pre-rigor foreshank positioning on the ultimate sarcomere length and objective tenderness values of seven chuck muscles. After final inspection, the left side foreshank was positioned caudal to the point of the shoulder and secured until the completion of rigor. The right side foreshank served as the control and was allowed to hang in the normal position, cranial to the point of the shoulder. Biceps brachii, infraspinatus, pectoralis profundus, serratus ventralis, supraspinatus, teres major and triceps brachii muscles were excised from each carcass half for sarcomere length and Warner–Bratzler shear force determinations.
Results indicate that sarcomere length was altered (P < 0.05) for all muscles. When the foreshank was placed in the caudal position pre-rigor, both the serratus ventralis and triceps brachii muscles had higher (P < 0.05) shear values than when the foreshank was allowed to remain in its natural position.
As the beef industry continues to search for methods to add value to the chuck, these data may offer insight into a practical method to increase sarcomere length and enhance palatability and marketability of underutilized muscles.
The effect of a moderate feed restriction (50 g feed/kg LW0.75[low feeding level, L] versus 70 g feed/kg LW0.75[high feeding level, H]) during the period previous to the late fattening phase on chemical composition, volatile profile and sensory quality of Iberian dry-cured loins from animals reared in free range (FR) or in confinement (C) along the fattening phase was studied. Total tocopherol, total free amino acid and ammonia contents of dry-cured loins from pigs FRL and FRH were higher (P < 0.05) than those from CL and CH. Sixty-one volatile compounds were identified and semiquantified in the headspace of all dry-cured loins. The FRL products showed the highest (P < 0.05) amino acid catabolism volatile compounds. In the rank-order test sensory analysis, the FR products obtained higher sums of ranks (P < 0.05) than those from confinement. Appearance, flavor, odor and texture scores showed a similar trend (FRL ≥ FRH > CL = CH).
Dry-cured products (loins and hams) from Iberian pigs that are reared at free range (FR) are highly appreciated by consumers, reaching the highest price. The feeding level of the Iberian pig in the period previous to the late fattening phase affects the amount of amino acid catabolism volatile compounds of dry-cured loins from pigs reared at FR which is reflected in a better sensorial quality of the dry-cured loin. A moderate feed restriction during the period previous to the late fattening phase of Iberian pigs reared at FR could be a good strategy to improve the sensory quality of dry-cured products.
The quantitative detection of the radiation-sterilized Salmonella typhimurium in a pure culture and ground beef, pork and chicken meat model system was evaluated using a visual immunoprecipitate (VIP) assay kit and an enzyme-linked immunosorbent assay (ELISA) method. The VIP kit and ELISA detected 105 cells/mL or above of the enriched culture of S. typhimurium, and the detection limit of the irradiated Salmonella was comparable to that of the intact cells. There was no significant difference between the detection limit of the enriched culture and that of inoculated and irradiated S. typhimurium in model system of ground beef, pork and chicken. Irradiation did not give any effect on the immunochemical detection of S. typhimurium within a dose of 5 kGy; therefore, an immunodetection method may be a simple way for the quantitative analysis of the indigenous microbes in a radiation-sterilized food.
One of the consumers' concerns about food irradiation technology is the abuse of the technology to sterilize food products without meeting the hygienic standard such as good manufacturing practice before irradiation of food. A simple method to detect the indigenous microorganism level before irradiation process is tested as a quality assurance measure using a pure culture of Salmonella typhimurium and inoculated meat model system. This simple test will be helpful by providing a trust for both consumer and manufacturer to verify that their products are produced under hygienic standard before irradiation treatment.
Injection enhancement with lactate darkens beef; however, the mechanism is unclear. Our objective was to assess the effects of lactate on beef myoglobin oxygenation. Nine strip loins were divided in half and one of three injection treatments (negative control − not injected, positive control − injected with water, and 3% lactate − injected with a water solution of lactate) was assigned to each half using an incomplete block design. Positive control and 3% lactate loins were pumped to 110% of green weight, cut into 2.54-cm thick steaks, overwrapped in polyvinyl chloride and stored at 4C. Steak surface darkening (L*), color stability (a* and metmyoglobin-reducing activity), depth of oxygen penetration and myoglobin oxygenation (1 h at 4C) were evaluated on days 0, 7 and 12 of storage. Lactate darkened color, decreased surface myoglobin oxygenation and limited oxygen penetration compared with controls (P < 0.05). Color stability was improved (P < 0.05) by lactate injection. The darkening effect of lactate may be associated with decreased myoglobin oxygenation.
Case-ready packaging has allowed beef purveyors to enhance meat with various ingredients, resulting in increased color and shelf life. Lactate is added as an antimicrobial agent; however, this beneficial effect can be somewhat diminished by lactate-induced darkening. Research assessing the mechanism(s) of lactate-induced beef color darkening is limited with previous research focused on determining the mechanism of lactate-induced color stability. The current research will give a better understanding of the role of lactate as an ingredient in beef steak darkening and, thus, provide a foundation that can be used to develop strategies to improve meat color.
This study was conducted to improve the qualities of meat curry prepared from tough sheep meat. Tenderization treatments given before or during preparation of meat curry included spraying of powder of dried cucumis fruits, marinating meat chunks in ginger rhizome paste, 0.75% citric acid solution, 0.6% papain enzyme solution or cooking of chunks in specially designed pressure cooker at 15 psi. All these tenderizing treatments caused significant improvement in sensory scores of sheep meat curry in comparison to control. Shear force and collagen values were significantly lower in all treated meat curry samples than the control. Although there was significant increase (P < 0.01) in thiobarbituric acid-reducing substance, pH and microbial load of meat curry on the fifth day of refrigerated storage, all the values were within the prescribed limits, and all samples were well acceptable. Magnitudes of changes during storage were less in citric acid- and ginger-treated chunks than the control and other treated chunks.
Different tenderizing agents suggested for tenderization of sheep meat can be easily used to improve the quality of meat curry. Conditions standardized for cooking tough meat at 15 psi proved very effective in improving the qualities of meat curry from spent animals in comparison to cooking of control samples in ordinary pressure cooker (at 10 psi). Cucumis powder proved very effective in improving all the sensory attributes. Use of citric acid and ginger extract can be recommended when meat curry is to be used after storage at refrigerated temperature.
These techniques of tenderization of tough meat before or during cooking can be easily adopted at small-scale and industrial levels. Improvement in tenderness will be of great value to meat processors and consumers. Better avenues for spent sheep meat utilization would also contribute for increased returns to the farmers. The process will not involve any significant extra expenditure, equipment or technique.
Rainbow trout with different fillet yield [56 and 65% for low (LY) and high yield (HY), respectively] were examined for muscle organization and flesh quality (instrumental and sensorial evaluations). Both groups had similar body weight (3.6 kg in mean), but the HY group had a higher carcass yield (+15%). Higher total muscle area in the HY group (+20%) was associated with a higher number of muscle fibers (+22%). Flesh of the HY group presented a higher area of myosepta (+10%), fat content (+10%) and luminosity (+6%). Raw fillet mechanical resistance was higher for the HY group; an opposite result was obtained for cooked flesh. Sensorial evaluation of cooked flesh revealed no important differences between groups. Smoked fillet from the HY group presented higher area of white stria and lower flesh color intensity. To conclude, higher muscle mass content had no negative consequences on flesh quality in rainbow trout.
Farmed rainbow trout presents great variability in fillet yield, and low fillet yield is considered as an unexpected carcass quality trait, as it leads to financial loss and higher volume of off-products, difficult to valorize. Therefore, the improvement of fillet yield appears as an interesting criterion for genetic selection, but only if increasing fillet yield does not result in a lower-quality product. This study provides useful information on the characteristics of the flesh of rainbow trout with different fillet yield. The results reported in this article show to fish farmers and processors that improving fillet yield has no negative impact on raw and processed flesh quality. From an academic point of view, this work provides additional knowledge in the area of the determinism of flesh quality in farmed fish.
The effects of apple polyphenol (AP) on color, lipid and protein oxidation in sliced cooked cured hams (SCCHs) made of pork and beef during chilled storage were investigated. SCCH samples with no antioxidant added and those treated with vitamin C were used as controls. The results indicated that addition of 500 ppm AP to the samples significantly inhibited discoloration in pork SCCH, but not in beef; all the AP treatments (with 300, 500 and 1,000 ppm AP) successfully inhibited lipid oxidation of both pork and beef SCCHs with the lipid of pork SCCH more effectively protected than that of beef SCCH. However, no effect on protein oxidation as measured carbonyl group accumulation was observed in both pork and beef SCCH treated with AP at the dose used in this study. AP was generally an effective antioxidant.
The results of the present study indicate that apple polyphenol (AP) may be used to retain the quality of hams in chilled storage and of other meat products in quality storage. However, different concentrations of AP have different effects on stored meat products, and the same concentration of AP may produce different effects on different meat products. Therefore, a test should be performed before application of AP to a specific meat product in meat industry.
The antioxidant activity of crude green tea polyphenol (GTP) on the lipid oxidation of carp (Cyprinus carpio L.) and catfish (Clarias gariepinus Burchell) was investigated. Each fish was trimmed to remove scales, head, fins, tail, viscera, bones, visible fat and skin, and treated with different concentrations of GTP 0.01, 0.03, 0.05 and 0.01% of vitamin C (VC). Control muscle sample (CK) contained no antioxidant. Lipid oxidation was evaluated over a course of 9 days and using a 3-day periodical interval analysis for peroxide value, thiobarbituric acid-reactive substances and free fatty acid. Carp minced fillet containing 0.03% GTP showed the best characteristics (P < 0.05) in relation to oxidative stability. For catfish, 0.05% GTP concentration was more effective in delaying lipid oxidation, when compared with the control sample and VC. However, 0.01%-treated minced fillet with VC was less effective than 0.01% GTP in reducing lipid oxidation. These results demonstrate that tea polyphenols inhibited lipid oxidation, and are effective alternatives to VC in food industry.
Green tea polyphenol (GTP) is a natural antioxidant. It can improve the quality of food products during refrigerated storage because of the presence of catechin in its composition. GTP promotes health by preventing lipid oxidation, and has been shown to possess antibacterial and antiviral characteristics. In food industry, it can be used as alternatives to the synthetic antioxidants because the use of these types of antioxidants is controlled nonetheless because of their carcinogenic potential.
This study was conducted to develop a method for improving tenderness and inhibiting oxidative change of yak meat by ginger extract (GE) treatment. Uniform-sized 3 cm × 3 cm × 3 cm yak meat chunks (Longissimus dorsi muscles) were marinated with distilled water, 3%, 5%, 7% GE and 0.2% sodium ascorbate, respectively. The samples stored for 24 h, 48 h and 72 h, and 3, 5, 7, 9 and 11 days at 4C ± 1C. The shear force values and cooking yield of the GE-treated samples were compared with that of the control groups, and thiobarbituric acid reactive substance (TBARS) value was compared with both the control group and the 0.2% sodium ascorbate-treated group. Significantly lower shear force values and TBARS value (P < 0.05) were observed in all the GE treatment samples, and the sodium ascorbate-treated group has similar TBARS with that of the 0.3% GE group. Cooking yields were also significantly higher in the GE-treated samples than that of the control groups (P < 0.05). Scanning electron microscope photos clearly depicted the extensively broken and swollen muscle fibers in the GE-treated samples. The results indicated that 5% (v/w) GE can be effectively utilized to tenderize tough yak meat and prevent yak meat from oxidation during storage.
Yak meat is an important protein resource for the Tibetan people, but yak meat was tougher and sensitive to oxidative change. This research would have practical applications to the yak meat processing and preservation. It can be applied at the industrial and household level as an easy method to improve yak meat quality and prevent yak meat from oxidation during storage.
The aim of this study was to identify and quantify hydrolyzed and free amino acids including taurine in different muscles of the Blonde Galician breed. The main essential amino acids present in each of the muscles were lysine and leucine, with aspartic acid and glutamic being the most important in the non-essential fraction. The chemical score and the index of essential amino acids were calculated as correlation parameters of the biological value of the proteins, with the best values being obtained for the muscles longisimus dorsi and semitendinosus. An analysis was also carried out of the amino acid in the free fraction. Taurine was found to be the main free amino acid in all muscles, with the exception of the cardiac muscle, where histidine was the main one present. The muscles that presented higher amounts of taurine were the masseter muscle followed by semimenbranous, and biceps femori, where taurine represented 40, 35, and 31%, respectively, of the total content of the free fraction.
This study provides practical and useful information on the nutritional quality of muscles, which are widely consumed in Spain. Several of these muscles are highly appreciated by the consumers in restaurants such as, eye of round, sirloin, and masseter muscle. These results will be relevant for the cattle industry, because this data add information to the fatty acid profile description of samples studied in the same breed. It will be also useful for nutritionists in describing tables of the food composition.
The effects of meat protein substitution (2%) with sodium caseinate, milk protein isolates or whey protein isolates (WPI) at varying levels of meat protein (13–15%) were studied in emulsified beef meat batters prepared with canola oil (25%). Increasing meat protein to 14 and 15% resulted in less stable emulsions (higher cook loss) compared with the 13% protein. At an equal protein level, all dairy proteins reduced cook loss (P < 0.05) compared with the all meat protein treatments. Overall, WPI provided the best emulsifying and moisture retention. Increasing the protein content also resulted in higher hardness and springiness values in all treatments. The addition of dairy protein resulted in softer, lighter and less red products compared with the all meat controls; colors being affected by the dairy protein source and protein content. Light microscopy revealed that increasing protein content caused some fat globule coalescence and more protein aggregation. WPI formed distinct dairy protein gel regions within the meat batter matrix, which appeared to interact with meat protein matrix.
The main goal of this study was to understand the effects of partially substituting meat proteins with dairy proteins on the performance (cook loss and textural properties) of comminuted meat batters prepared with canola oil. The incorporation of canola oil, instead of animal fat, offers a new healthy alternative to the consumer but has its challenges in terms of keeping this liquid oil (high unsaturation level) within the meat product).
The aim of this work was to evaluate the effectiveness of metal hydroxide immobilization and five different DNA extraction methods in detection of Salmonella enterica from pork sausage samples by nested polymerase chain reaction (PCR). Immobilization of bacterial cells by Zr(OH)4 and Ti(OH)4 was carried out prior to DNA extraction by five DNA extraction methods. The fliC gene and enterotoxin (stn) gene of Salmonella enterica was amplified by nested PCR. Both metal hydroxide immobilization and nested PCR amplification were able to increase the detection sensitivity. DNA extraction by modified Fontana and Kapperud methods were more effective compared with other methods. The amplification of enterotoxin (stn) gene provided more sensitivity of detection compared with amplification of fliC gene. This study shows that the use of metal hydroxide immobilization and nested PCR are able to increase the sensitivity of Salmonella enterica detection from meat food samples.
In this experiment, two extraction methods were found to be more effective for the extraction of DNA from Salmonella enterica-spiked pork sausage. Immobilization of Salmonella cells by metal hydroxide and application of nested polymerase chain reaction were able to increase the detection sensitivity and reduce the possibility of false positive results. These findings are useful in the selection of suitable methods for rapid, sensitive and reliable detection of bacterial pathogens from meat food samples.
The antioxidant and antimicrobial effects of each of different forms of garlic and BHA in emulsion-type sausage at 4C for 0, 10, 20 and 30 days were investigated. The treatments were divided into five groups: control, 30 g of fresh garlic /kg of sausage, 9 g of garlic powder /kg of sausage, 100 mL of garlic extract/kg of sausage and 0.1 g of BHA/kg of sausage. pH, peroxide value (POV), thiobarbituric acid reactive substance (TBARS), residual nitrite contents (RN) and total aerobic plate count (TAPC) were evaluated during storage. pH values and RN contents showed a significant decrease in all treatments during storage days. With the exception of POV value at 30 days of storage, an increase in POV, TBARS and TAPCs was observed in all treatments as storage time increased. In addition, the treatment with different forms of garlic and BHA during storage reduced pH, POV, TBARS, RN and TAPCs when compared with control. Consequently, the use of fresh garlic had much better antioxidant and antimicrobial effectiveness than other treatments.
Antioxidant or antimicrobial effectiveness is one of the major factors related to consumer acceptance for determining the quality of meat and meat products and their shelf life. The current study can be applied to prevent lipid oxidation and growth of microorganism in emulsion-type sausage and to produce new sausage formulations for a gradually increasing consumer acceptance. Based on the results, different forms of garlic can be used to improve oxidative stability of emulsion-type sausage and decrease the growth of microorganisms proving its antioxidant and antimicrobial effectiveness. The employment of natural additives in food preparations is perceived by consumers as a healthier practice than the addition of synthetic additives.
Midwestern meat processors were surveyed to determine whether consensus existed among industry processing practices for jerky production. Seventy-eight plants were contacted, 37 responded and 33 plants sent 61 samples consisting of whole muscle (56%) or chopped and formed (44%) jerky. Samples had mean water activity, salt (NaCl) and pH of 0.74, 6.85% and 5.85, respectively. Plants used either smokehouses (34) or commercial ovens (3). Nine plants measured wet bulb temperature, and one used a relative humidity instrument. However, 35 plants claimed that they were able to control humidity. Controls included closing dampers, steam injection, direct addition of water, placing a pan of water in the house, or a combination of methods. Plants used sodium nitrite (32), sodium erythorbate (15) and potassium sorbate (5), and vacuum (78%), no vacuum (32%) and gas flush (14%) packaging. Most products were stored at room temperature (38%) or refrigerated (32%); or a combination of methods was used.
Because of the high variability of processing times and temperatures, processing environment relative humidity, and methods to control humidity used by small and very small plants, there is a need to educate these processors about jerky processing parameters and the need for routine product analysis. Lack of processing knowledge and equipment capabilities also highlights the need for lethality studies in this area in addition to education on jerky process control and food safety for processors. On the basis of the averages from this study, lethality studies should target Aw 0.74 (Food Safety Inspection Service requires an Aw of ≤0.85), NaCl 6.85% and pH 5.85. Lethality studies should be conducted with cure for most studies. Marinade pH and length of time held in marinade prior to thermal processing as well as packaging effect and subsequent shelf life on pathogen lethality during storage should be considered. This research information could potentially decrease plants' operating costs while helping ensure food safety and public health protection.
Changes in salt extractable protein (SEP) and Ca2+-ATPase activity of actomyosin from washed and unwashed silver carp stored at −10 and −20C were investigated. The resultant decrease of SEP and Ca2+-ATPase activity mainly occurred in the first 5 and 7 weeks, and the changes obeyed first-order model. The kinetic models of SEP and Ca2+-ATPase changes were established during frozen storage. The rate constant k of decline in SEP and Ca2+-ATPase activity of samples stored at −10C were higher than that of samples stored at −20C; the D value of samples stored at −10C were lower than that of samples stored at −20C. Compared with washed samples, unwashed samples had a higher rate constant k and activation energies E, and a lower D value. Activation energies E of SEP were higher than E of Ca2+-ATPase activity in all samples.
Silver carp is one of the main freshwater fish species in China. Washing is an important step for fish processing and temperature is an important factor on fish protein storage. The changes of the kinetic models of SEP and Ca2+-ATPase during frozen storage can explain the effect of temperature and time on silver carp mince quality. These kinetic models can be used to predict the silver carp protein functional changes during frozen storage, and help to provide better methods to effectively utilize silver carp protein resource.