Curing Ingredients Research Articles

Improving the functional and technological properties of minced pork using a proteolytic enzyme

The use of pork obtained from intensively growing hybrid animals as the main raw material in meat processing, in particular sausage production, is accompanied by undesirable variability of consumer characteristics of sausage products and a decrease in the economic indicators of enterprise performance. The main technological disadvantages of processed pork are reduced water-binding capacity and significant loss of meat fluid, which in practice is usually compensated by the increased use of food additives and non-meat ingredients. The aim of the study was to assess the possibility of targeted improvement of the technological properties of minced pork using a proteolytic enzyme of animal origin. Model samples of minced meat were developed and cured for 24 hours at a temperature of 4 °C. The following control samples were used: minced meat with the addition of 2% edible salt and minced meat with the addition of 2% edible salt and 0.2% sodium bicarbonate. Moreover, 0.0001% chymotrypsin was added to the test samples containing similar curing ingredients. During electrophoretic study, in samples with the enzyme, an increase in low-molecular fractions (20 kDa, 15 kDa and lower) was observed, which indicated the manifestation of proteolytic activity of chymotrypsin in model systems. Enzymatic treatment led to an increase in pH and water-binding capacity. Cooking loss was reduced by 3 to 6 times, compared to Control 1. After cooking, histological studies of model systems showed that the test samples subjected to enzymatic treatment were characterized by a denser arrangement of structural elements, less pronounced cellular components of muscle tissue and the presence of glutin formed as a result of protein breakdown, filling the microcapillaries. Thus, the use of an enzyme preparation provides an opportunity for targeted improvement of the technological properties of pork obtained from intensively growing hybrid animals.

Treasuring waste lignin as superior reinforcing filler in high cis-polybutadiene rubber: A direct comparative study with standard reinforcing silica and carbon black

There has been ever raising concern in last few decades about the utilization of biomass for different commercial applications such as filler materials in rubber composites. In this context, an interesting pathway has been proposed to develop such composites by introducing waste lignin as a reinforcing constituent in high cis-polybutadiene rubber (BR). With a judicious selection of rubber curing ingredients and, simultaneously, adopting suitable solid-state mixing protocols, particularly, a relatively high-temperature multi-steps melt-mixing process (above the glass transition temperature of lignin), rubber composites with an outstanding mechanical performance were prepared. The reinforced rubber composites with 50 (weight) parts lignin loading per hundred parts of rubber (phr) offer ∼10 MPa tensile strength (TS), ∼276% elongation at break (EB), and ∼3.51 MPa tensile stress at 100% elongation (so-called rubber modulus M100). These values are superior when compared with the composites comprised with standard reinforcing carbon black (∼8.5 TS, ∼224% EB, ∼2.79 M100) and even with a silica-silane system (∼7.34 TS, ∼229% EB, ∼2.44 M100) with same filler loading. The unique combination of the curing packages and four-stage mixing process allowed us to establish a homogeneous and fine dispersion of lignin. Furthermore, this is the first time that available models of rubber reinforcement are applied to the description of the reinforcement mechanisms of lignin in a soft elastomer involving various aspects like filler-filler interaction, rubber-filler interactions, critical strains for destroying the filler-filler network, effective filler volume fractions, shape factor, etc. The developed compounding methods for BR and their characterization and modeling can be easily applied to other commercial rubbers facilitating a real breakthrough in developing cheap and bio-based high-performance rubber composites.

Biological value of semi-smoked sausages with cedar oil cake

Introduction. Development of novel meat products with better quality and biological value remains one of priority objectives of modern food industry. New meat products correspond with the principles of healthy diet due to their improved fatty acid profile and lower sodium content. The present research featured semi-smoked sausages with 15% of cedar oilcake and a low-sodium curing mix. The cedar nut oilcake is as a source of highly unsaturated fatty acids and high-grade protein. In addition to the physiological effect, the low-sodium curing mix increases the resistance of the combined fat phase to deterioration during storage.
 Study objects and methods. Sausages of control and experimental formulations were made in laboratory conditions. The control formulation included raw second-grade beef, semi-fat pork (30% of fat), and traditional curing ingredients, i.e. sodium chloride and nitrite curing mix. In the experimental formulation, 15% of the semi-fat pork was replaced by cedar oil cake, and 30% of sodium chloride – by magnesium chloride. The samples were tested for fatty and amino acid composition, biological value of the lipid and protein phase, chemical composition, as well as physical, chemical, and sensory properties. Other research data included water activity, as well as acid, peroxide, and thiobarbituric value during storage at a temperature of 4 ± 2°C for 15 days.
 Results and discussion. The study of fatty acid composition showed significant differences in the ratio of saturated (SFA), monounsaturated (MUFA), and polyunsaturated fatty acids (PUFA, P ˂ 0.05) in the samples. When 15% of pork was replaced by cedar oilcake, the amount of SFA decreased by 19.8%, while the content of MUFA and PUFA increased by 10.2% and 24.9%, respectively. These changes improved the indices of atherogenicity and thrombogenicity. The quality of the protein component also improved, as the utility coefficient of amino acids increased from 0.83 to 0.87, and the coefficient of comparable redundancy decreased from 7.2 g/100 g of protein to 5.35 g/100 g of protein. The sausages with cedar oil cake and low sodium chloride content received a high consumer evaluation. The hydrolysis of the lipid fraction was the same in both samples. The process of lipid oxidation was inhibited, which can partially be explained by a lower water activity.
 Conclusion. The biological value, consumer quality, and storage stability of semi-smoked sausages could be improved by replacing fat-containing meat raw materials with cedar oil cake and reducing sodium chloride content. The new product demonstrated a better nutrition quality and can be recommended for mass production.

Utilization of Phosphate Alternatives in Marinated Chicken Breast and Chunked and Formed Deli Ham

Experiments were conducted to determine the efficacy of replacing phosphates in marinated chicken and chunked and formed deli ham using alternative ingredient blends. For the marinated chicken study, broiler breasts were marinated with a 13% solution of 1.0% NaCl, water and either 0.35% sodium tripolyphosphate or a phosphate alternative. Treatment variables consisted of (1) 0.35% sodium tripolyphosphate (STP), (2) negative control (no phosphate, NP), (3) 0.83% Whey protein concentrate (WPC), (4) 0.83% Oat fiber (OF, marinated chicken only), or (5) 1.05% Oat fiber with dry vinegar (OFDV).The WPC, OF, and OF-DV treatments also included 1,000 ppm of a natural flavor that served as an antioxidant. The STP treatment yielded breast meat with less (P < 0.05) cooking loss and a higher pH (P < 0.05) than the NP and alternative ingredient treatments. On average, no differences were observed (P > 0.05) in consumer acceptability for chicken breast appearance, texture and overall acceptability. For the ham study, each treatment formulation consisted of approximately 77% pork, 20% water, common commercial curing ingredients, and the following treatment effects: STP (0.4% STP), NP (no phosphate, NP), 1.3% OF-DV, and 1.1% WPC. STP had less cooking loss than all other treatments (P < 0.05). The STP treatment had greater protein bind (P < 0.05) than all other treatments, and the OF-DV treatment had greater protein bind than the WPC and NP treatments. The NP, STP, and WPC treatments were preferred (P < 0.05) over the OF-DV treatment. Application of WPC or OF-DV may help meat processors meet current clean label trends if the decrease in yields for chicken breast and deli hams and the decrease in firmness of texture in deli hams is acceptable to processors and consumers.

Effects of Plum Concentrate, Potato Starch, and Rice Starch as a Phosphate Replacement on Quality and Sensory Attributes of Whole Muscle Hams

ObjectivesThe purpose of this study was to evaluate the functionality of potato starch (PS), rice starch (RS), and plum concentrate (PC) as a replacement for phosphates in clean label curing brines, determined by the industry significant attributes of smokehouse yields, sensory analysis, and color scores.Materials and MethodsFresh inside ham pieces (Semimembranosus + Adductor) (n = 80), USDA-IMPS # 402F, were denuded and split into halves. Inside ham pieces were randomly assigned to one of four treatments including: a control containing traditional curing ingredients (CON), and three treatments with natural curing alternatives containing either plum concentrate (PC), potato starch (PS), or rice starch (RS) as phosphate replacement. Clean label treatment hams (CLT) were evaluated in conjunction with a traditional processed ham control (CON). The control brine was made with the addition of phosphate; whereas, the three clean label treatment brines received phosphate replacement inclusion via the vacuum tumbler. The ham pieces from all treatments were injected to approximately 125% of their fresh weight using a multi- needle injector. Hams were vacuum tumbled with a target post tumble weight of 130%. Inclusion rates for treatments included 2.25% (PS, RS) and 1.1% (PC) of the projected final meat block weight. Hams were then tumbled for 2 h at –15 mm Hg and 12 RPM (industry standard). Hams were cooked to an internal temperature of 62.7°C without the addition of smoke and chilled in accordance with USDA-FSIS Appendix B. They were then vacuum packaged and held under refrigeration (4°C) for 21d. Hams were evaluated for smokehouse yields, sensory analysis, and color scores. Ham samples were evaluated for: initial and sustained juiciness, initial and sustained tenderness, off flavors, ham flavor intensity, and mouth feel. Ham slices were held vacuum packaged, under refrigeration for an additional 7d, and then evaluated for L*, a*, b* color space values at 28d post cooking to simulate a retail setting. Differences in treatment results were analyzed using the MIXED models procedure of SAS.ResultsHams treated with PS had the highest cooking and overall yield (P < 0.05), PC hams had the lowest cooking and overall yield (P < 0.05), and RS hams were comparable to CON. The CLT were darker and less red than CON (P < 0.05). Similarly, CON had the highest a* value (P < 0.05) indicating a significant redder color compared to PS, RS, and PC; additionally, CON had a higher b* (P < 0.05) compared to clean label treatments. The CON had decreased tenderness compared to CLT (P < 0.05). For all other sensory attributes CLT was comparable to CON. Trained sensory analysis determined all phosphate replacements maintained or improved sensory attributes over the control. Cooking yields were improved by PS, held similar by RS, and decreased significantly by PC when compared to the control. Both PS and RS should be considered acceptable phosphate replacements in natural curing brines.ConclusionBased on research presented, PS and RS are suitable replacement for phosphates in natural curing brines based on similar or improved yields, and similar or improved sensory attributes. Due to its extreme cooking loss PC is not a recommended phosphate replacement.

Effects of Plum Concentrate, Potato Starch, and Rice Starch as a Phosphate Replacement on Quality and Sensory Attributes of Whole Muscle Hams

ObjectivesThe purpose of this study was to evaluate the functionality of potato starch (PS), rice starch (RS), and plum concentrate (PC) as a replacement for phosphates in clean label curing brines, determined by the industry significant attributes of smokehouse yields, sensory analysis, and color scores.Materials and MethodsFresh inside ham pieces (Semimembranosus + Adductor) (n = 80), USDA-IMPS # 402F, were denuded and split into halves. Inside ham pieces were randomly assigned to one of four treatments including: a control containing traditional curing ingredients (CON), and three treatments with natural curing alternatives containing either plum concentrate (PC), potato starch (PS), or rice starch (RS) as phosphate replacement. Clean label treatment hams (CLT) were evaluated in conjunction with a traditional processed ham control (CON). The control brine was made with the addition of phosphate; whereas, the three clean label treatment brines received phosphate replacement inclusion via the vacuum tumbler. The ham pieces from all treatments were injected to approximately 125% of their fresh weight using a multi- needle injector. Hams were vacuum tumbled with a target post tumble weight of 130%. Inclusion rates for treatments included 2.25% (PS, RS) and 1.1% (PC) of the projected final meat block weight. Hams were then tumbled for 2 h at –15 mm Hg and 12 RPM (industry standard). Hams were cooked to an internal temperature of 62.7°C without the addition of smoke and chilled in accordance with USDA-FSIS Appendix B. They were then vacuum packaged and held under refrigeration (4°C) for 21d. Hams were evaluated for smokehouse yields, sensory analysis, and color scores. Ham samples were evaluated for: initial and sustained juiciness, initial and sustained tenderness, off flavors, ham flavor intensity, and mouth feel. Ham slices were held vacuum packaged, under refrigeration for an additional 7d, and then evaluated for L*, a*, b* color space values at 28d post cooking to simulate a retail setting. Differences in treatment results were analyzed using the MIXED models procedure of SAS.ResultsHams treated with PS had the highest cooking and overall yield (P < 0.05), PC hams had the lowest cooking and overall yield (P < 0.05), and RS hams were comparable to CON. The CLT were darker and less red than CON (P < 0.05). Similarly, CON had the highest a* value (P < 0.05) indicating a significant redder color compared to PS, RS, and PC; additionally, CON had a higher b* (P < 0.05) compared to clean label treatments. The CON had decreased tenderness compared to CLT (P < 0.05). For all other sensory attributes CLT was comparable to CON. Trained sensory analysis determined all phosphate replacements maintained or improved sensory attributes over the control. Cooking yields were improved by PS, held similar by RS, and decreased significantly by PC when compared to the control. Both PS and RS should be considered acceptable phosphate replacements in natural curing brines.ConclusionBased on research presented, PS and RS are suitable replacement for phosphates in natural curing brines based on similar or improved yields, and similar or improved sensory attributes. Due to its extreme cooking loss PC is not a recommended phosphate replacement.

Microbial load, physico-chemical properties, and organic acid profile of a naturally fermented carabeef, Pindang damulag, as affected by fermentation time

Pindang damulag or fermented carabeef is a native traditional food from Pampanga, Philippines. It is produced by mixing thin slices of carabeef with curing ingredients, then storing the mixture in an anaerobic condition, and left through the action of naturally growing lactic acid bacteria (LAB) via fermentation for 1 week at room temperature. However, the practice of production and consumption of pindang damulag is slowly dying and there are only very limited scientific studies on pindang damulag. Therefore, the study aimed to identify the LAB present and determine its contribution to the microbial diversity, physico-chemical properties, and organic acid profile of pindang damulag during natural fermentation. During fermentation, standard serial dilution and plating show that all targeted groups of microorganisms (fungi, common bacteria, coliforms, acid producing bacteria and LAB) grew significantly until the 3rd day. After day 3, only acid producing bacteria and LAB grew significantly. There was also a significant decrease in total soluble solids (TSS) from day 0 to day 3 (30.31 – 28.17°Brix), while titratable acidity (TA) and pH were found to be statistically constant (3.5% at pH 5.97 – 3.6% at pH 5.9). Moreover, significant decrease in TSS (24.89, 22.76, and 20.53°Brix) and pH (5.60, 4.93, and 4.53) were observed, while TA increased significantly (4.5, 5.6, 6.6%) during days 5, 7, and 9. After the culture dependent phenotypic and genotypic tests using 27F and 1492R primer pairs, LAB isolates were found to be homologous to Enterococcus faecium and Weisella paramesenteroides. The former exhibited proteolytic activity on pindang damulag which broke down the protein chains with approximate MW of 20.1KDalton as observed in the acrylamide gel from SDS-PAGE. The other LAB was known to be a heterofermentative LAB, which reflected on the predominance of other organic acids such as citric acid (448.70 mg/100 g), acetic acid (1724 mg/100 g) other than the lactic acid (4440 mg/100 g) alone, using RP-HPLC. Therefore, LAB was found to have a major role in the food safety, food quality and overall profile of pindang damulag.

Effects of nitrite source, reducing compounds, and holding time on cured color development in a cured meat model system

To meet the growing demand for “cleaner” foods, many meat processors have begun using plant-based curing ingredients. The purpose of this project was to determine the effects of nitrite source (sodium nitrite or cultured celery juice powder), reducing compounds (no reducing compound or sodium erythorbate/ascorbic acid from cherry powder), and holding time prior to cooking on cured color development using a meat model system. Treatments with reducing compounds had greater cured pigment and reduced residual nitrite (P < 0.001, P = 0.003, respectively), and displayed increased redness (P < 0.001) and decreased yellowness (P = 0.016). Sodium nitrite treatments had greater cured meat pigment, increased redness, and decreased yellowness (P < 0.001). Longer holding times resulted in a slight increase in a* values when held 60 min (P = 0.011). Using a pre-converted celery juice powder and ascorbic acid from cherry powder, processors can manufacture cured meats exhibiting typical cured meat characteristics without extended holding time prior to cooking.

Sensory and physicochemical characteristics of salamis added with vegetable-based curing ingredients

ABSTRACT: The aim of this study was to evaluate the sensory and physicochemical quality of colonial salamis added with vegetable-based curing ingredients as potential enhancers of quality products. Salamis were produced according to three treatments: (A) Control: 0.1% curing salt; (B) rosemary: 0.05% curing salt + 0.5% rosemary extract (RE); and (C) RE+celery: 0.14% Veg 503 + 0.27% Veg 504 (sea salt plus celery, nitrate and nitrite supplies, respectively) + 0.5% of RE. No significant differences were observed (P&gt;0.05) among the three treatments for dry matter (DM), crude protein (CP), ash, ether extract (EE) and gross energy (GE). Sensory analysis was performed by applying the preference test and multiple comparison between the three treatments. Salamis added with vegetable-based curing ingredients were sensory equivalent to conventional level of curing salts. Vegetable extracts allowed the development of the sensory features of salami and did not interfere in the fermentation process. Results suggested that the extracts can serve as effective natural curing ingredients for the ripening process and cured meat color as well as adequate shelf-life replacing the commercial curing salts in meat and meat products. After 30 days of ripening, salami from the control treatment (conventional levels of nitrite and nitrate) and the treatments with added vegetable-based curing ingredients and low nitrite and nitrate content (RE and RE + celery) were equivalent in sensory quality.

Effect of chicken skin on the quality characteristics of semi-dried restructured jerky

The objective of this study was to evaluate the effect of skin on the textural properties of semi-dried jerky produced with different acid treatments. Jerky was prepared with no skin (control) or with 1, 3, or 5% chicken skin. After hand mixing (for 3 min) and tumbling (for 30 min) to distribute the curing ingredients, the cured meats were dried for 180 min at 55°C, for 180 min at 65°C, and finally for 60 min at 75°C. The presence of skin was shown to result in a higher fat content, TBA value, and metmyoglobin due to the high fat content of the skin. In contrast, acid treatment decreased the TBA value and metmyoglobin in jerky relative to samples that were not subjected to acid treatment. The presence of skin also improved the moisture contents, processing yields, and mechanical tenderness.

Influence of Modified Inorganic Fillers on Thermal and Spectral Properties of N-component System of Polymer Blends

The inorganic (mineral) fillers based on kaolinite and montmorillonite are important ingredients which affect the characteristics of polymer mixtures and their products. Apart from rubber, chemistry of sulfur vulcanization affects the vulcanization system, which consists of vulcanizing agent, activators and accelerators. To proceed the sulfur vulcanization, is an important step the interaction between the curing ingredients and the creation of active sulfurating agent, which is involved in the networking of rubber macromolecules. This article is concerned with examining the interactions between the components of the vulcanization system and modified mineral fillers on the basis of clay minerals, namely phyllosilicates structure type 1:1 (kaolinite) and structure type 2:1 (montmorillonite), without the use of a polymeric matrix. Prepared n-component systems of the type of component / components – clay (in 1:1 ratio by mass) were studied by IR spectroscopy, X-ray diffraction analysis and thermal methods that allow detection of changes in the course of reactions rubber components, without the presence of the rubber matrix.

Antioxidant activities and nutritional characteristics of smoked duck marinated in natural curing agent

Purpose: This study investigated the question of whether the addition of natural ingredients (pear fermented solution, celery powder, vitamin C) in curing agents may influence antioxidant activities and nutritional characteristics of smoked duck. Methods: Smoked duck samples with general or natural curing agent containing three additive ingredients were examined to determine total polyphenol contents, antioxidant activities, pH, TBARS, and food additives residue (nitrite ion, antioxidant, sodium glutamate). Results: Smoked duck with natural curing agent showed a higher level of total polyphenol content and antioxidant activities than smoked duck using general curing agent (p < 0.05). The pH and TBARS of smoked duck were significantly decreased by the addition of natural curing ingredients compared to those of smoked duck using general curing agent (p < 0.05). The residues of food additives were not detected in smoked duck using natural curing agent. Conclusion: Findings suggest that the addition of pear fermented solution, celery powder, and vitamin C in natural duck curing agent may improve the antioxidant activities and nutritional characteristics of smoked duck and provides health benefits.

Marination with natural curing ingredients, storage time, and serving temperature effects on the sensory characteristics of forage-finished or commercially-sourced beef roasts

Beef inside round roasts (n=144) were cut from rounds obtained from both forage-finished cattle (n=72) and commercially-sourced beef (n=72). Roasts were portioned to weigh 0.45–0.68kg each. Each roast was then randomly assigned one of the following treatments: control, injected-no cure, or injected-cured. Additionally, roasts were assigned a serving temperature (hot or cold) and storage treatments (0d or 28d post cooking). Roasts from forage-fed beef had a more red interior color and higher shear values, and also retained more brine than commercially-sourced beef (P<0.05). Curing roasts improved TBARS values in roasts served hot and significantly reduced sensory warmed-over and grassy flavors (P<0.05). Marinating forage-finished beef roasts significantly improves tenderness and flavor characteristics.

EFFECTS OF pH VALUES AND FAT CONTENT ON SODIUM CHLORIDE DIFFUSION RATE IN PORK

Chloride diffusion was studied in pale, soft, exudative (PSE) pork meat of pH 5.4 to 5.5, normal-quality meat of pH 5.6 to 5.7 and dark, firm, dry (DFD) meat of pH 6.6 to 6.8, as well as in meat-fat batters of 10, 20 and 30% of fat. Cylindrical glass pipes filled with meat or batter were immersed into brine containing 16% NaCl and 0.16% NaNO2. After 24, 48, 72, 96, 120, 144 and 168 h of curing, chloride content in samples was measured and effective diffusion coefficient (Def) was calculated. Along with the decrease of pH of meat, sodium chloride content increased and higher Def was noted. Chloride concentration in the internal layer of PSE meat was about 80% higher compared with the normal-quality meat and about 130% higher than in DFD meat. Chloride Def decreased significantly with the increase of fat content in meat-fat batter. PRACTICAL APPLICATIONS Besides technological benefits of curing process in meat, excessive residues of the reacting curing ingredients can lead to the direct toxicological effects. Thus, there is a need to optimize the curing process in the direction to determine a precise dosage of the curing substances and appropriate time of curing which depends on the chemical composition of raw material as well as its biochemical condition. The results obtained in the study enabled to adjust the curing time of meat of different pH and fat content. Meat of lower pH should be cured shorter than normal-quality meat, whereas dark, firm, dry meat (high pH) should be cured longer. Fat content in raw meat also significantly affects the salt migration rate. With increase of fat content, the time of curing should be longer. The described findings might be helpful in designing the technological process.

Effects of rubber curing ingredients and phenolic‐resin on mechanical, thermal, and morphological characteristics of rubber/phenolic‐resin blends

AbstractThis article examines the physical and mechanical characteristics of mixtures of two different synthetic rubbers, namely styrene‐butadiene rubber (SBR) and nitril‐butadiene rubber (NBR), with novolac type phenolic‐resin (PH). According to Taguchi experimental design method, it is shown that the addition of PH increases the crosslinking density of rubber phase probably due to its curative effects. Thermal analysis of the blends indicates that, contrary to NBR/PH blend, thermal stability of SBR/PH blend is dependent on sulfur content due to predominant polysulfidic crosslinks formed in SBR. Slight shift in glass‐transition temperature (Tg) of pure SBR and NBR vulcanizates by the addition of PH suggests that both SBR/PH and NBR/PH are incompatible blends with a partially soluble PH in the rubber phase. Two‐phase morphology of the mixtures is also evidenced by scanning electron microscopy. Correlation of the rubber/PH modulus versus PH concentration by Halpin‐Tsai model shows a deviation from the model. Presence of PH in the rubber phase is thought to vary the mechanical properties of the rubber phase by changing both the crosslinking density and rigidity of the molecular network of the rubber, leading to misuse of modulus of pure rubber in Halpin‐Tsai equation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Growth inhibition of heat-injured Enterococcus faecium by oligophosphates in a cured meat model

Cells of two heat-resistant strains of Enterococcus faecium were heated and incubated in meat suspensions containing curing ingredients. The concentrations of the curing ingredients were those frequently used for pasteurized ham-type products, except that the concentrations of the oligophosphates (triphosphate and diphosphate) varied. Heating tests at 69 °C were performed with inoculated meat suspensions in heat-sealed plastic pouches. Numbers of bacteria were counted immediately after heating and in parallel series of heated pouches incubated at 37 °C. Plating was performed in Tryptone Dextrose Yeast Meat Peptonised Milk Agar (TDYMP); in TDYMP Agar to which the curing ingredients were added; and in TDYMP Agar to which the curing ingredients except oligophosphates were added. The inclusion of oligophosphates in the heating medium increased the heat-injury sustained by the E. faecium cells, and in combination with rather severe heat treatment even completely blocked the growth of surviving organisms in the meat suspension incubated at 37 °C. The presence of oligophosphates in the culture medium TDYMP Agar severely reduced the counts of freshly heated cells; however, this effect disappeared after repair and growth of the surviving organisms in the meat suspension.

Influence of Milk Co-precipitates on the Quality of Restructured Buffalo Meat Blocks

Restructuring had made it possible to utilize lower value cuts and meat trimmings from spent animals by providing convenience in product preparation besides enhancing tenderness, palatability and value. Milk co-precipitates (MCP) have been reported to improve the nutritional and functional properties of certain meat products. This study was undertaken to evaluate the influence of incorporation of milk co-precipitates at four different levels viz. 0, 10, 15 and 20% on the quality of restructured buffalo meat blocks. Low-calcium milk co-precipitates were prepared from skim milk by heat and salt coagulation of milk proteins. Meat chunks were mixed with the curing ingredients and chilled water in a Hobart mixer for 5 minutes, followed by addition of milk co-precipitates along with condiments and spice mix and again mixed for 5 minutes. Treated chunks were stuffed in aluminium moulds and cooked in steam without pressure for 1.5 h. After cooking, treated meat blocks were compared for different physico-chemical and sensory attributes. Meat blocks incorporated with 10% MCP were significantly better (p 0.05) differences were observed in cohesiveness, springiness, gumminess and chewiness of both type of samples. (Asian- Aust. J. Anim. Sci. 2004. Vol 17, No. 4 : 564-568)

Mechanistic aspects of the role of coupling agents in silica–rubber composites

Compared to carbon black, the use of silica as reinforcing filler for rubber results in lower hysteretic losses, for tyre applications leading to lower rolling resistance and consequently fuel savings. The compatibility of hydrophilic silica with a hydrophobic rubber polymer matrix is generally poor. Adding bi-functional coupling agents to the compounds, commonly bis(triethoxysilylpropyl) tetrasulphide (TESPT), enhances filler-matrix compatibility. The degree of hydrophobation of silica during rubber mixing then depends on many mutually interacting factors. Irreproducible conditions during mixing and vulcanisation are major causes of irreproducibility of silica-reinforced rubber compounds. Depending on the chemical composition of the coupling agent, the ultimate temperature obtained during the mixing process turns out to be the main factor governing the reactions of the coupling agent: the formation of a proper bond between the silica and the coupling agent, while avoiding a premature reaction with the rubber polymers, leading to premature scorch during mixing. Further, the mechanistic aspects of the reaction of various coupling agents, variants on TESPT, are covered, with silica as well as with the rubber. Of great importance are: the carbon and sulphur chain-lengths within the coupling agents, whether corrections are applied in the compound with elemental sulphur relative to the sulphur contained in the reference TESPT, and the moments the correcting amounts of sulphur are added to the compounds: during the first mixing stage, or together with the curing ingredients later-on in the process. The tensile properties of the vulcanised compounds are most prominently influenced. This is indicative of the dual role of sulphur: on the one hand as direct curative, on the other hand as part of the coupling agent becoming attached to the rubber polymers.

The potential of vancomycin-resistant enterococci to persist in fermented and pasteurised meat products

Experiments with 148 isolates of vancomycin-resistant enterococci (VRE) were performed to assess their potential to persist and grow in fermented sausages and pasteurised meat products. All strains were meat isolates and Van-type A, except a single VanC1 strain. In total, 143 strains of Enterococcus faecium were involved. Eight selected strains were examined for their potential to grow at high salt and nitrite levels and at reduced pH. The same isolates were used in experiments with fermented sausages. All available strains were subjected to heating tests in meat suspensions with added curing ingredients. All but one of the eight tested isolates grew at pH 4.0 in tryptone soya broth (TSB). With the combination of 8% w/w NaCl, 400 ppm NaNO 2 and 0.5% w/w glucose in the meat suspension, all isolates grew at 37 °C, whereas none grew at 7 °C even after 56 days. With the addition of 10% w/w NaCl, 200 ppm NaNO 2 and 0.5% w/w glucose, still one E. faecium isolate grew at 37 °C, although very slowly. Overall, the strains tolerated high salt and nitrite concentrations and reduced pH very well, even beyond levels applied in the regular production of fermented and/or pasteurised meat products. The tested strains could be isolated after the fermentation and further ripening of “boerenmetworst” and “snijworst”. Overall, their colony counts decreased on average about 1 log-unit over a period of 60 days after batter manufacture. All 148 isolates demonstrated a relatively weak thermal resistance compared to results for selected vancomycin-sensitive enterococci strains reported in the literature and to results collected under identical experimental conditions in this laboratory. None of the strains (log inoculation level about 5–6 ml −1 for each isolate) could be cultured after heating at 70 °C for 10 min.

DRY‐CURED MEDITERRANEAN HAMS: LONG PROCESS, SLOW CHANGES AND HIGH QUALITY: A REVIEW1

ABSTRACTThe term “curing”, in the Mediterranean region of Europe, means a long period of aging where an intense enzymatic action develops the distinctive flavor of dry‐cured hams. The traditional process consists of rubbing a mixture of dry curing ingredients over the entire surface of the hams, allowing time for uniform distribution of the curing ingredients, and finally, a ripening stage where the product is submitted to different cycles of temperature, humidity and time. The final unique taste and flavor (a complex of sensations resulting from the stimulation of odor and taste) are achieved by proteolytic and lipolytic action. This lipolytic and oxidative degradation joined with the catabolism of amino acids produce volatile compounds, particularly during ripening under high temperature, which are responsible for the typical aroma of dry‐cured hams. Raw material (the use of Duroc genetic material in growing pigs and feeding of acorns) and ripening conditions play an important role in dry‐cured ham production in this area of the world.