Influence of storage period and packaging method on sliced dry cured beef "Cecina de Leon": Effects on microbiological, physicochemical and sensory quality

Quality aspects of sliced dry-cured beef “Cecina de León” preserved in vacuum and gas mixtures (20%/80% CO₂/N₂ and 80%/20% CO₂/N₂) were studied. The evolution of microbiological, physicochemical and sensory parameters were analysed during storage (210 days) at 6 °C. Although microbial counts at 60 days of the gas-packaged samples were lower than the vacuum-packed ones, they were never higher than the spoilage limit (7 log ufc/g). A slight increase (p < 0.05) in pH was observed throughout storage of “Cecina de León” packaged under vacuum and in gas mixtures. However, a decrease (p < 0.05) in a_w was observed during storage of “Cecina de León” packaged under vacuum but a_w did not vary (p > 0.05) during storage in the gas-packaged samples. No changes were observed (p > 0.05) in lightness (L^*), redness (a^*) and yellowness (b^*) in vacuum and gas packaged samples during storage. However, sensorially evaluated colour showed lower values in gas packaged samples during 30 days storage. This difference was decisive in establishing the shelf-life of “Cecina de León” slices preserved in gas mixtures (20%/80% CO₂/N₂ and 80%/20% CO₂/N₂). Therefore, from a microbiological point of view, gas mixtures are more effective in extending the shelf-life of “Cecina de León” slices. It is concluded that vacuum packaging allows longer storage than gas-packaging as it maintains a good visual appearance of “Cecina de León”, the main parameter in consumers’ perception of meat quality.     

Effect of salt and transglutaminase (TG) level and processing conditions on quality characteristics of phosphate-free, cooked, restructured pork shoulder

Six treatments of phosphate-free restructured cooked pork shoulder were produced with two salt levels (2% and 1%) and three transglutaminase levels (0%, 0.075% and 0.15%) under two processing conditions (72 °C/65 min and 78 °C/65 min). Salt level significantly affected (p < 0.05) the chemical composition, the cooking losses, the colour, the sensory attributes and the overall acceptability of the product. Transglutaminase level affected (p < 0.05) only the consistency and the overall acceptability. The processing conditions on the contrary, affected the moisture and the protein content, the cooking losses, the consistency and the juiciness of restructured cooked pork shoulder. Transglutaminase can be used at a level of 0.15% with reduced salt level (1%) and processing at 72 °C/65 min to produce phosphate-free restructured cooked pork shoulder with acceptable sensory attributes.     

Quality and shelf life evaluation of fermented sausages of buffalo meat with different levels of heart and fat

Investigations were carried to study the effect of heart incorporation (0%, 15% and 20%) and increasing levels of fat (20% and 25%) on physicochemical (pH, moisture content and thiobarbituric acid, TBA number) and microbiological (total plate count and yeast and mold count) quality and shelf life of semi dry sausages of buffalo meat during refrigerated storage (4 °C). Different levels of fat significantly (p < 0.05) increased the pH of the sausage samples. However different levels of heart incorporation did not significantly (p < 0.05) affect pH, moisture content and TBA number of sausage samples. Fresh samples had pH, moisture content and TBA number in the range of 5.15–5.28, 42.4–47.4% and 0.073–0.134 respectively. Refrigerated storage significantly (p < 0.05) increased TBA number of control samples while storage did not significantly (p < 0.05) increase the TBA number of sodium ascorbate (SA) treated samples. Total plate counts of twelve sausage samples were f under the TFTC (too few to count) limit at the initial stage. Incorporation of different levels of heart and also increasing levels of fat did not significantly (p < 0.05) increase the log TPC/g values. Yeast and molds were not detected in twelve samples of semi dry fermented sausages in their fresh condition. Storage revealed that there was a consistent decrease in pH, and moisture content. Refrigerated storage significantly (p < 0.05) reduced both pH and moisture contents. TBA number and total plate counts and yeast and mold counts of controls were found to increase significantly (p < 0.05) during refrigerated storage. However, in SA treated sausage, only TPC and yeast and mold count significantly (p < 0.05) increased during refrigerated storage. Shelf life of the sausages was found to be 60 days under refrigerated storage (4 °C).     

The influence of early post-mortem enhancement and accelerated chilling on pork quality

To improve pork quality, the effectiveness of early post-mortem enhancement and accelerated chilling were investigated. The four treatments evaluated were: Enhancement with Accelerated Chilling (ENAC), Accelerated Chilling Only (ACO), Enhancement with Conventional Chilling (ENCC), and Conventional Chilling Only (CCO). ENAC had a higher (P < 0.05) pH than all other treatments. CCO resulted in the highest (lightest; P < 0.05) L^*, while ENAC had the lowest L^* value (darkest; P < 0.05). Subjective color and striping did not differ (P > 0.05) between ENAC and ENCC, although ENAC was numerically higher for both parameters. Sensory analysis for juiciness and tenderness were not different (P > 0.05) between ENAC and ENCC, but both were higher (P < 0.05) than ACO and CCO. Enhancement early post-mortem coupled with accelerated chilling may be used to improve instrumental color and pH over conventional processing methods.     

Modification of the bitterness of caffeine

Caffeine is the worlds most consumed psychoactive chemical and as such is a valuable commodity to the food and beverage industry. Caffeine also activates the bitter taste system causing a potential problem for manufacturers wanting to develop products containing caffeine. In the present study both oral peripheral and central cognitive strategies were used in an attempt to suppress the bitterness of caffeine. Subjects (n = 33) assessed the influence of sodium gluconate (100 mM), zinc lactate (5 mM), sucrose (125 mM and 250 mM), milk (0%, 2% and 4% milk fat), and aromas (coffee, chocolate, mocha) on the bitterness of caffeine (1.5, 3 and 4.5 mM). The oral peripheral strategies proved most effective at suppressing the bitterness of caffeine: zinc lactate (−71%, p < 0.05), non-fat milk (−49%, p < 0.05), and sodium gluconate (−31%). Central cognitive strategies were partially effective: 250 mM sucrose (−47%, p < 0.05) and mocha aroma (−10%) decreased bitterness, while chocolate (+32%) and coffee (+17%) aromas increased perceived bitterness. Overall, zinc lactate was the most effective bitterness inhibitor, however the utility of zinc in foods is negated by its ability to inhibit sweetness.     

Sodium chloride levels in comminuted chicken muscle in relation to processing characteristics and Fresnel reflectance detected with a polarimetric probe

Increasing NaCl from 0 to 2% in comminuted samples of chicken breast meat increased the resistance to compression of cooked samples (r=0.98, p < 0.001), increased water-holding capacity (r=0.95, p < 0.001), decreased cooking losses (r=−0.97, p < 0.001) and decreased paleness (L^*) before and after cooking (r = −0.96 and r=−0.99, respectively, p < 0.001). The decrease in paleness caused by NaCl was associated with an increase in the relative amount of reflected light maintaining its original plane of polarisation, so that NaCl% was correlated with an extinction coefficient for polarised light, r=0.91, p < 0.001. A possible explanation is that myofibrillar proteins may have been dissolved at high levels of NaCl, thus reducing light scattering by myofibrils and allowing more Fresnel reflectance to be detected.     

Meat quality characteristics of springbok (Antidorcas marsupialis). 4: Sensory meat evaluation as influenced by age, gender and production region

The effects of age, gender and production region on the sensory characteristics of springbok M. longissimus dorsi (LD) were investigated in 19 springbok, which originated from two Nature Reserves in the Free State Province of South Africa and were divided into age (adult, sub-adult) and gender categories. The sensory characteristics evaluated were game meat aroma, juiciness, residual tissue, tenderness and game meat flavour. Age, gender and production region had an effect (P < 0.05) on different sensory ratings of the meat. Whereas production region influenced (P < 0.05) the game meat aroma, initial juiciness, sustained juiciness and residual tissue ratings of the meat, gender and age had a significant effect on only the residual tissue rating of the meat. An interaction (P < 0.01) between age, gender and production region was observed for the tenderness attribute where the males from the Gariep Nature Reserve were the only gender that showed a significantly higher tenderness rating in the sub-adult than in the adult category. Sensory ratings were linearly correlated with certain physical and chemical attributes. Warner–Bratzler shear force (kg/1.27 cm diameter) values were inversely correlated with the sensory attributes of tenderness (r = −0.70, P < 0.01), residual tissue (r = −0.68, P < 0.01) and sustained juiciness (r = −0.43; P < 0.05). Age-related effects on perceived tenderness were minor in comparison with pH effects. As the pH₂₄ of the meat increased, tenderness (r = −0.46, P < 0.05) and sustained juiciness (r = −0.54, P < 0.05) decreased significantly. No significant linear correlations were observed between the intramuscular fat (IMF) content and the sustained juiciness ratings of the meat. It can be concluded that production region had some influence on sensory characteristics of springbok meat, whilst the influence of age and gender were negligible.     

Chemical, physical and sensory properties of meat from pure and crossbred Podolian bulls at different ageing times

The present study aimed to investigate the effect of crossbreeding with Limousine sires on fatty acid profile, physical and sensory properties of meat produced by Podolian young bulls. Polyunsaturated fatty acid content was influenced by crossbreeding (P < 0.01) with Podolian bulls (P) producing beef characterised by a higher level of unsaturation in comparison with crossbred animals (LP). As a consequence, P/S ratio was significantly higher in meat produced by P animals than LP (P < 0.01). P animals had higher linoleic (P < 0.05), linolenic (P < 0.05), EPA (P < 0.05) and DHA acids (P < 0.001) levels than LP subjects. No breed effect was observed for the ratio n − 6/n − 3 (P > 0.05). WBS force of LD was significantly lower in meat from crossbred subjects (P < 0.05). Both crossbreeding with Limousine and extension of ageing from 2 to 7 days improved LD tenderness as assessed by panel taste (P < 0.001).     

Effect of γ-irradiation on the sensory quality of moist beef biltong

Moist beef biltong (mean moisture content = 46.7% and a_w = 0.919) was vacuum packaged and irradiated to target doses of 0, 2, 4, 6, and 8 kGy. Thiobarbituric acid reactive substance (TBARS) measurements and sensory difference and hedonic tests were performed to determine the effect of γ-irradiation on the sensory quality of the biltong. TBARS values only increased significantly (P < 0.05) if biltong was irradiated to at least 8 kGy, indicating a low degree of lipid oxidation. This can be attributed to the low fat content (on average 1.53%) of the biltong used in this study, as well as irradiation under vacuum conditions. All irradiated samples could be discriminated (P < 0.05) from non-irradiated biltong, but none was rated as less acceptable. Dissipation of volatiles before tasting (by exposing the product to aerobic conditions before consumption), a low degree of lipid oxidation and liking of distinct ‘irradiation flavours’ possibly all attributed to the flavour of irradiated biltong not being regarded as unacceptable compared to controls. Biltong irradiated at 2 and 4 kGy was however liked significantly more (P < 0.05) than other samples, indicating that slight, non-oxidative irradiation-induced flavour changes may contribute to flavour development in the usually more bland moist beef biltong. Although lean moist beef biltong can thus be irradiated to doses up to 8 kGy without adversely affecting the sensory acceptability, low dose irradiation (4 kGy) is most feasible to optimise the sensory quality.     

Studies on tenderization and preparation of enrobed pork chunks in microwave oven

This study was conducted to develop technology for tenderization and production of enrobed pork chunks in a microwave oven. Meat chunks from shoulder cuts of pork were cured in a solution containing salt, sodium tripolyphosphate and sugar for 48 h at 4 ± 1 °C, enrobed with cream based batter and cooked in a microwave oven at 900 MHz. These enrobed chunks (control) were compared with tenderized (treated) enrobed chunks, for which 7.5% cucumis extract, 9% ginger extract and 0.50% papain powder were incorporated in the standard curing solution. Ginger and papain treatments caused significant (P < 0.01) increases in the moisture content and pH of the cooked products compared to the control and cucumis treated samples. Shear force values were significantly (P < 0.01) lower and overall acceptability scores were significantly (P < 0.01) higher in all treated samples compared to the control. During storage at 4 ± 1 °C, the moisture contents and sensory qualities decreased, but TBARS values and microbial counts increased significantly (P < 0.01). Although all products were acceptable up to 15 days of storage, the ginger treated samples had significantly (P < 0.01) lower TBARS and microbial loads and higher sensory attributes than the control, cucumis and papain treated samples. The magnitude of the storage changes were less and acceptability ranking was higher for the ginger treated samples compared with the others. The results indicated that microwaves could be used for the preparation of enrobed pork chunks. The overall acceptability and shelf life of microwave cooked enrobed pork chunk can be further improved using ginger extract in the curing solution.     

Genotype and gender differences in carnosine extracts and antioxidant activities of chicken breast and thigh meats

The aim of this work was to investigate the effects of genotypes and gender of chickens on carnosine contents and their antioxidant activities. The carnosine content of fresh meat from Thai indigenous and hybrid native chickens differed between breeds (p < 0.01) and genders (p < 0.01). Regardless of these differences, breast meat contained 2–4-fold higher carnosine than thigh meat. After water and heat extraction at 80 °C and ultrafiltration, the carnosine content of meat extracts had the same distribution as in fresh meat. No relationship between total iron and carnosine content on antioxidant activity of the extract was detected. However, when compared in the extracts on the basis of mM carnosine in oxidation system, the extracts of chicken meat showed greater antioxidant activity than pure carnosine (p < 0.05). Furthermore, at equal concentrations, thigh meat extract had higher effective inhibiting ability than breast extract.     

Different micronization methods significantly improve the functionality of carrot insoluble fibre

This study was to investigate the effects of different micronization methods, including ball milling, jet milling and high-pressure micronization on the characteristics and various functional properties of carrot insoluble fibre-rich fraction (FRF). The results demonstrated that these treatments could effectively (p < 0.05) pulverize the fibre particles to different micro-sizes. As particle size decreased, the bulk density of the insoluble FRF was significantly (p < 0.05) decreased and a redistribution of fibre components from insoluble to soluble fractions was observed. Furthermore, these treatments, especially the high-pressure micronization, could significantly (p < 0.05) increase the physicochemical properties (e.g., water-holding capacity, swelling capacity, oil-holding capacity and cation-exchange capacity), glucose adsorption capacity, -amylase inhibitory activity and pancreatic lipase inhibitory activity of the insoluble FRF to different extents (from several to 29-fold). Our findings suggested that these micronization treatments would provide an opportunity to improve the functionality of carrot insoluble FRF in food applications.     

Effect of fiber type on postmortem proteolysis in longissimus muscle of Landrace and Korean native black pigs

The current study was conducted to characterize objective meat quality, fiber type and their relations to postmortem proteolysis in longissimus muscle of Landrace and Korean native black (KNP) pigs. Longissimus muscles from each 10 market-weighted male pigs were removed after conventional slaughtering and chilling procedures, and aged for 1 or 7 days at 4 °C to determine WB-shear force, objective meat color, proportion of myosin heavy chain I (MyHC I), intramuscular fat content and rate of proteolysis by a proteomics approach. KNP had a significantly (p < 0.05) higher content of MyHC I, and that concurred with greatly (p < 0.05) higher intramuscular fat content and Hunter a^* value, and significantly (p < 0.05) lower drip loss than those seen in Landrace. One-dimension SDS-PAGE indicated that GAPDH, troponin I and creatine kinase were prominent proteolytic products during chiller ageing. By applying a gel-based proteome analysis, 26 proteins were identified, which showed different degradation properties during ageing between the breeds. Biopsied sample revealed that myosin regulatory light chain 2, myosin light chain isotype v/sb, fatty acid-binding protein and albumin were expressed at a greatly higher level for KNP, but their relation to fiber type (or genetic background) is unclear. It was particular noticeable that different actin isoforms showed various degradation behavior during ageing time.     

Chemical, instrumental and sensory characteristics of cooked pork ham

Instrumental, chemical and sensory parameters of cooked pork ham were evaluated. Principal component analysis was carried out on the basis of the instrumental variables related to colour and texture. The four PCs account for almost 94% of the total variance in the data set. The PCA only separated 3 hams with a^* > 10. Hardness was correlated with non-collagen muscle protein (P  0.01), gumminess (P  0.01) and ash (P  0.05). Sensory evaluated tenderness showed positive significant correlation with L^* (P  0.01). The most important colour parameter seems to be a^*, which was negatively correlated with sensory evaluated parameter colour (P  0.01). The PCA performed on all parameters (sensory, chemical and textural) discriminated two groups of hams differing in non-collagen muscle protein content and hardness.     

Physicochemical and sensory properties of chicken nuggets with washed mechanically deboned chicken meat: Research note

The effects of different proportions (0%, 10%, 20%, 30%, 40%) of washed mechanically deboned chicken meat (WM) as a substitute for hand deboned chicken meat, on the physicochemical and sensory characteristics of chicken nuggets were evaluated. The addition of WM increased fat content, but it was only significant (P < 0.05) when 40% of WM was added, whereas the protein content was significantly (P < 0.05) reduced as from 20%. Significant differences (P < 0.05) were found in L^*, a^* and b^* values with different proportions of WM, however, these differences were evidently not discerned as shown by the no significant differences (P > 0.05) in ΔE^* color scores. The addition of WM did not affect (P > 0.05) sensory attributes of chicken nuggets. From a technical viewpoint, up to 40% WM could be incorporated into nugget formulation instead of hand deboned chicken meat without affecting sensory attributes of the product. Minor changes in composition were observed but they were probably not detrimental to the product.     

Toasting of corn flakes: Product characteristics as a function of processing conditions

Toasting of corn flake is an important processing step that dictates the attributes of the finished product with particular reference to consumer acceptability. The effect of important toasting variables such as moisture content, temperature and time of toasting of corn flakes on quality attributes has been investigated employing response surface methodology (RSM). A central composite experimental design consisting of five coded levels (−1.682, −1, 0, 1 and 1.682) of each independent variables has been employed. The response functions are thickness of flake, bulk density, puncture force, colour parameters and the sensory overall acceptability. Further, the changes in the microstructure of the flakes have been monitored. The energy expenditure during the toasting process was also determined, and 721–746 J g⁻¹ of energy was required to have properly toasted flakes. These response functions can be correlated (r  0.82, p  0.01) with the independent variables by second order polynomials consisting of linear, quadratic and interaction terms. The effect of temperature and time usually dominates over the moisture content for toasting of corn flakes. Optimum conditions for achieving best puffing and overall acceptability have been obtained.     

Effects of breed and marination on the sensory attributes of pork from Large White and Hampshire-sired pigs

The effects of breed and marination were tested for their effects on meat pH, water holding (marinade uptake and losses) and eating quality (tenderness, juiciness and flavour).

Loins were removed from one side of 20 Large White-sired and 20 Hampshire-sired pigs after slaughter, cut into four pieces and injected to 112% of their initial weight with water, a polyphosphate-containing marinade (pH 7.7) or a high pH marinade (pH 10.3). An uninjected piece of loin served as control. Samples were left overnight and then frozen before being thawed, cooked and assessed by a trained ten member sensory panel using 1–8 category scales.

Hampshires had higher intramuscular fat (0.95%) than Large Whites (0.62%) but otherwise the effects of breed were small compared with marination. Both marinades significantly increased meat pH from 5.5 (control) by 0.2 U, significantly reduced the cooking loss and increased the meat yield from about 80% to 90%. Water-injected samples lost large amounts of added water as drip after thawing and had a yield (76%) similar to the control. Marinaded samples retained more water post-cooking. Both marinades significantly increased tenderness (p < 0.001) and juiciness (p < 0.001) by about 1.0 U compared with the control (4.4 for tenderness and 4.2 for juiciness). Pork flavour, however, was significantly reduced (p < 0.001) and abnormal flavour was significantly increased (p < 0.001) by marination. Tenderness was positively correlated with pH after injection (0.83) and yield (0.75); juiciness was also positively correlated with pH after injection (0.78) and yield (0.87).

The absence of any significant difference in eating quality between control and water-injected samples, and the relatively large effects of marination, suggest that retained water (after cooking) is crucial in determining perceived tenderness and juiciness in pork.     

Effects of the inclusion of sodium bicarbonate and sugar beet pulp in the concentrate for fattening lambs on acid-base status and meat characteristics

Thirty-six young Merino lambs (15.3 kg live weight) were allocated into four equal groups to study the effects of the inclusion of sodium bicarbonate (‘Bic’, 0 vs. 2%) and sugar beet pulp (‘SBP’, 0 vs. 12%) in the concentrate on meat characteristics. Lambs were fed barley straw and concentrate ad libitum. When they reached 25 kg a blood sample was taken and the animal slaughtered. After 24 h meat characteristics (pH, colour, water holding capacity, Warner–Bratzler shear force, chemical and fatty acid – ‘FA’ – composition) were measured on M. longissimus thoracis et lumborum. SBP replacing 24% of the barley in the concentrate caused an increase in shear force (P < 0.05) and saturated FA (P < 0.05), decreasing meat unsaturated FA (P < 0.05). SB increased blood base excess (P < 0.05) and meat yellowness (P < 0.05) and decreased meat pH (P < 0.05), without altering any other meat characteristics.