Rapid (microwave) heating rate effects on texture,fat/water holding,and microstructure of cooked comminuted meat batters

Comminuted and gelled, fat-containing meat products such as frankfurters and luncheon meats are commercially processed by heating relatively slowly (for up to 2 h or more) to an endpoint of about 70 °C prior to cooling. This study compared such a slow, ramp heating regime (0.5 °C/min), terminated at 70 °C, to rapid, square-wave cooking (one step: rapid 100 °C/min heating to 70 °C endpoint, plus isothermal holding prior to cooling, or two-step: rapid heating to 50 °C, holding, then rapid heating to 70 °C plus holding prior to cooling) on meat batter gel properties (fracture and small strain rheology, microstructure, cook loss, and expressible water). The results indicated that a rapid cooking process, with its inherent advantages of reduced process time, lower equipment footprint, and more efficient use of energy, can produce a product nearly equivalent in textural properties and cook yield to one processed by traditional smokehouse cooking when the cook value of the processes is similar and an intermediate (near 50 °C) holding step is included (two-step rapid heating). One-step rapid heating negatively affected gel structural homogeneity and water/fat holding properties of fat-containing gels.     

Influence of cooking conditions on cooking loss and tenderness of raw and marinated chicken breast meat

The influence of different cooking treatments on tenderness and cooking loss, as main quality characteristics of chicken breast meat, was investigated. Industrial skinless chicken breast meat samples were designated as raw and marinated and cooked in the oven by hot air and hot air-steam mixture at 130, 150 and 170 °C, for 4, 8 and 12 min. Cooking losses were evaluated by weight changes before and after cooking, and tenderness changes were determined on cooked samples by measuring shear force using instrumental texture analysis. Results showed that marination, followed by air-steam cooking is the best combination to obtain the most tender chicken breast slices. The time and temperature of cooking showed similar effects on cooking loss and tenderness: short cooking time (4 min) and temperatures of 130–150 °C resulted in lower cooking losses and best meat tenderness, in both not marinated and marinated meat. Statistically significant correlations between tenderness and cooking loss indicated that the cooking loss correlated better with cooking time than with cooking temperature. An opposite phenomenon was observed for meat tenderness.     

Aluminium contents in baked meats wrapped in aluminium foil

In this investigation, the effect of cooking treatments (60 min at 150 °C, 40 min at 200 °C, and 20 min at 250 °C) on aluminium contents of meats (beef, water buffalo, mutton, chicken and turkey) baked in aluminium foil were evaluated. Cooking increased the aluminium concentration of both the white and red meats. The increase was 89–378% in red meats and 76–215% in poultry. The least increase (76–115%) was observed in the samples baked for 60 min at 150 °C, while the highest increase (153–378%) was in samples baked for 20 min at 250 °C. It was determined that the fat content of meat in addition to the cooking process affected the migration of aluminium (r² = 0.83; P < 0.01). It was also found that raw chicken and turkey breast meat contained higher amounts of aluminium than the raw chicken and turkey leg meat, respectively. Regarding the suggested provisional tolerable daily intake of 1 mg Al/kg body weight per day of the FAO/WHO Expert Committee on Food Additives, there are no evident risks to the health of the consumer from using aluminium foil to cook meats. However, eating meals prepared in aluminium foil may carry a risk to the health by adding to other aluminium sources.     

Use of meat fluorescence emission as a marker of oxidation promoted by cooking

Accumulation of fluorescent pigments in cooked bovine meat (M. Longissimus thoracis) was studied in relationship with the heating parameters (time and temperature). Muscles were aged at 4 °C for 11 days under vacuum before cooking. Meat cooking was performed by applying jets of steam. Three different heating treatments were tested: two with constant surface temperatures of 65 and 96 °C for 300 s, and one with a continuously increasing surface temperature up to 207 °C. After extraction in water/dichloromethane/ethanol, fluorescence pigments were distributed between the apolar phase (emission 420–440 nm after excitation at 360 nm) and the polar phase, where two emission peaks were seen (emission 410–430 and 515 nm after excitation at 360 nm). Fluorescence in the two phases was little affected by heating at the two constant temperatures while it increased exponentially after 1 min of treatment, as the varying temperature reached 141 °C. The maximum fluorescence increases, measured in the extreme conditions of cooking (207 °C/300 s), were of 5000% in the apolar phase and 1700% in the polar phase. Thiobarbituric acid reactive substances (TBARS) and protein carbonyls were measured in parallel. The correlations between these two parameters and the fluorescence emission demonstrated that the interaction between proteins and aldehyde products of lipid peroxidation was mainly involved in the production of fluorescent pigments in cooked meat.     

Effects of high pressure processing on protein fractions of blue crab (Callinectes sapidus) meat

The studies about the effect of high pressure processing (HPP) on the myofibrillar proteins of crab meat are scarce in the literature. The aim of this study is to evaluate the effect of high pressure processing (HPP) at 100, 300 and 600 MPa (10 °C/5 min) on the muscular protein fractions of blue crab meat (Callinectes sapidus) and compares the effect of high pressure treatments and the thermal cooking process on the yielding of crab meat. Differential scanning calorimetry analysis of raw crab meat showed two peaks at 48.18 and 76.76 °C corresponding to myosin and actin denaturation. The increasing in the pressure level resulted in a decrease in denaturation enthalpy of both proteins. Data from Fourier transform infrared spectroscopy indicated changes in the secondary protein structures in which a reduction in α-helix and an increase in β-turn were observed as a result of denaturation induced by HPP. Electrophoresis analysis (SDS-PAGE) showed myofibrillar protein denaturation as the pressure level increased. The HPP at 100 and 300 MPa resulted in a significant increase in the yielding of meat extracted when compared to the thermal treatment (90 °C/20 min). Higher sensory scores were obtained in 300 and 600 MPa suggesting higher acceptance. Results suggest the feasibility of applying HPP as an alternative to the thermal treatment to process crab meat.Industrial relevanceHigh pressure processing (HPP) technology has been successfully applied to several seafood products. However, it is important to study the effect of HPP on the food components, mainly proteins in the crab meat to optimize the processing parameters to get high-quality products. In the present study, the benefit of using HPP as an alternative to the commercial thermal processing for extraction of crab meat has been confirmed. Applying 600 MPa (10 °C/5 min) to the whole blue crab resulted in a higher yield of extracted crab meat compared with the other treatments. However, using a range of 100–300 MPa (10 °C/5 min) also increases the yielding of extracted crab meat when compared to the thermal process, and moreover, the extraction procedure is faster. The quality and the functional properties of the crab meat with fresh appearance is preserved after the treatment at 100 MPa. These results could promote subsequent applications of pressurized crab meat in the crab industry, especially with the HPP treatments in a range between 100 and 300 MPa.     

Thermal inactivation of Bacillus anthracis Sterne in irradiated ground beef heated in a water bath or cooked on commercial grills

The thermal stability of heat-shocked and non-heat-shocked spores of the virulence-attenuated Sterne strain of Bacillus anthracis was evaluated at select temperatures in irradiated, raw ground beef (25% fat) heated in a water bath or cooked using two different commercial grills. For the former, 3-g portions of inoculated ground beef were packaged in bags that were completely immersed in a temperature-controlled circulating water bath held at 65 °C (149 °F), 70 °C (158 °F), 75°(167 °F), and 80 °C (176 °F) for a predetermined length of time. For the latter, formed ground beef patties (95-g each) were inoculated with spore stock A or B of the Sterne strain and then cooked on a commercial open-flame gas grill or on a commercial clamshell electric grill to achieve target internal temperatures of either 71.1 °C (160 °F), 82.2 °C (180 °F), or 93.3 °C (200 °F). Cooking ground beef patties on commercial grills, resulted in reductions of ca. 0.8 to 3.5 log₁₀ CFU/g for spore stocks A and B of B. anthracis Sterne after heating to 71.1 °C (160 °F), 82.2 °C (180 °F), or 93.3 °C (200 °F) on either the open-flame gas grill which required ca. 9.6 min to reach the target internal temperatures or on the clamshell electric grill which required ca. 4.0 min to reach the target internal temperatures. In comparison, our data using a water bath system and heating at 65° to 80 °C predict nearly 4 log reductions in spore levels for short times, ~½ min, depending possibly on the temperature. Thus, our data suggest that models based on heating ground beef in a water bath is not a good predictor of reductions of levels of spores of B. anthracis Sterne strain that would be obtained when cooking ground beef patties on commercial grills under conditions that may be typically used by consumers and/or retail establishments. Nevertheless, our data validated that cooking ground beef patties on a commercial grill at a temperature considered to be “well-done” and a temperature (71.1 °C;160 °F) recommended by the USDA/FSIS, is effective at killing spores of B. anthracis Sterne.Industrial relevanceHeating ground beef in a water bath or cooking ground beef patties on commercial grills under conditions simulating those that are used by consumers and/or that occur in retail food service establishments is effective at killing spores of B. anthracis Sterne.     

Acid and moisture uptake in steamed and boiled sweet potatoes and associated structural changes during in vitro gastric digestion

Orange-fleshed sweet potatoes are a good source of phytochemicals. For these nutrients to be absorbed, they must be released from the food matrix as a result of physical and chemical breakdown. A key factor in food breakdown is gastric acid diffusion into the matrix, and its influence on structural changes. Cooking treatment may influence mass transport properties and structural changes of foods during digestion. The objective of this study was to determine the acid and moisture uptake into sweet potatoes and its influence on macro- and micro-structures during in vitro gastric digestion as a result of varying cooking treatments. Sweet potatoes were cut into cubes and cooked (boiled or steamed) for different times. In vitro oral and gastric digestions were simulated in a shaking water bath at 37 °C. Acidity, moisture content, and solid loss were measured after 9 digestion times (15 to 240 min). Hardness of individual cubes and microstructure (light microscopy) were completed before and after digestion. Effective diffusivity of acid and moisture into the cubes was estimated using MATLAB. Cooking method, cooking severity, and digestion time significantly influenced moisture uptake (p < 0.0001). Acid uptake was significantly influenced by digestion time (p < 0.0001). The change of softening after digestion was influenced by cooking method and severity (p < 0.05). Effective diffusivity of acid ranged from 0.03 × 10^− 10 (mild steamed) to 11.40 × 10^− 10 m²/s (severely boiled). Percent texture decrease after digestion from the initial hardness ranged from 16% (severely steamed) to 34% (mild boiled). Textural changes were related to cell wall breakdown and starch degradation. In general, mass transport properties and macro- and microstructural changes were influenced by cooking treatment and gastric digestion. The link between food cooking and behavior during digestion is crucial in determining optimal food processing and cooking methods for specific food functional properties.     

Characterization of endogenous enzymes of milled rice and its application to rice cooking

The relationship between the activities of endogenous enzymes in milled rice and accumulation of chemical components in the rice grains during cooking was investigated. Maltose and soluble starch were optimally hydrolyzed around 60 °C by both crude extracts and purified α-glucosidases of milled rice. Gelatinization onset temperature of rice flour was determined to be 63 °C with DSC analysis under usual cooking condition. Hydrolytic activities on carbohydrates and proteolytic activities of milled rice were enhanced at pH 5 compared to pH 7 at the range of 4–80 °C. When rice was cooked at pH 5, glucose and amino acids highly accumulated with soaking for 16 h before heating. We propose a new method of cooking with prolonged soaking at acidic pH, which is effective for increasing the amounts of chemical components in cooked rice.     

Sensory and Microbiological Parameters of Stored Wild Boar Meat

The influence of temperature on microbiological and sensory parameters of wild boar meat kept for 21 days was studied. Total viable count was higher in meat stored at 15 °C than at lower temperatures on day 21. Colour saturation and hue did not differ at any temperature, but odor differences occurred in meat at 15 °C. Redness (a*) in meat at 0 °C was higher than at 15 °C. Meat stored at 0 or 15 °C differed in b* after 21 days, and in L* after 7 days. Observance of National and European legislation concerning handling of wild game is important in providing health-friendly meat.     

Effect of radio frequency (RF) heating on the texture,colour and sensory properties of a comminuted pork meat product

Radio frequency (RF) cooking is a form of dielectric heating in which products are heated by subjecting them to an alternating electromagnetic field between two parallel electrodes. Although similar in some respects to Microwave heating, RF has been proposed to be more suitable for industrial heating of meats because of the greater penetration depths possible with this technology. In this study an RF cooking protocol was developed and its effect on selected quality attributes of pork based white pudding was examined. Whilst cooking of the product in air proved unfeasible due to arcing, use of a polyethylene cell with circulating hot water (80 °C) facilitated successful heating of the product. Application of RF using an optimised cooking protocol (RF power = 450 W, cell volume = 500 ml and continuous circulation) resulted in a mean end-point temperature of 73 °C after 7 min 40 s. Similar mean end-point temperatures in water bath and steam oven heated products were achieved after 29 and 33 min, respectively. A factorial experiment was conducted to assess selected quality attributes of the cooked puddings. Results show that RF heated puddings were not significantly different (P > 0.05) from water bath and steam oven heated products with regard to instrumental colour, instrumental texture (Kramer shear and texture profile analysis) and expressible fluid. Furthermore, results of a sensory similarity test involving 60 panellists indicated that panellists were not able to detect differences between puddings cooked by RF and conventional methods. Overall this suggests that RF heating technology could have potential in pasteurisation of meat products though further work is needed to verify this.     

“Chilled” pork—Part I: Sensory and physico-chemical quality

Chilled meat exportation comprises chilling within 48 h post-mortem to temperatures < 0 °C without freezing and holding under these conditions for several weeks. The effects of this ageing on sensory quality of pork are unknown and hence the objective of this study was to compare the sensory quality of Canadian pork as found in an export (Japan) market and locally. Regardless that the Japanese market's quality criteria were met, pork sorted on-line differed (P < 0.05) from that for the domestic market only for lightness, exudate and cooking loss; no differences in intramuscular fat content were observed. Overall, a trained panel scored weaker pork and meat flavours and odours in the export than the domestic pork as a result of either the quality by selection if roasted or the ageing (− 1.7 °C, 43 days exported chilled or 3.1 °C, 5 days domestic) if grilled or shabu shabu. Grilled pork was also more tender, sweeter and had stronger caramel flavour with the chilled ageing.     

Water absorption as an evaluation method of cooking quality for yam (Dioscorea alata) and cassava (Manihot esculenta crantz)

Water absorption as a new method of cooking quality (hard cooking or mealy cooking) of yam and cassava cultivars determination was studied by cooking eight (08) cultivars. 30 g of each were boiled in 500 ml of water during 20 minutes and dried at 70 °C for 15 hours and 103 °C for 3 hours in a vacuum oven. Results showed that cassava and yam have different cooking quality. Dry matter content does not influence the cooking quality of yam and cassava. Mealy cooking quality of yam absorbs less water (6.6%) during cooking but looses more soluble dry matter (9.5%) during the same process. Hard cooking quality of yam absorbs much water (23.5%), but looses less soluble dry matter (3.9%). The soluble dry matter is the main parameter to determine the quality of D. alata. It stands at 9.5% ± 2.9 for mealy cooking quality and 3.9 ± 0.73 for hard cooking quality cultivars of D. alata. Water absorbed by mealy cooking cassava (27.6%) is significantly (p < 0.05) higher compared to water absorbed of hard cooking cassava (12.4%). Water absorbed during cooking is the main parameter in determining the quality of cassava cultivars. Water absorbed stands at 27.6% ± 8.8 for mealy cooked quality and 12.4% ± 1.9, for hard cooked quality of cassava cultivars. A close relation between water absorption and cooking quality was revealed to contribute to a better selection procedure for cultivars in the frame of food security.     

Effect of chilling applied to suckling lamb carcasses on hygienic,physicochemical and sensory meat quality

The effect of post mortem temperature treatment on suckling lamb carcass and meat quality was study. Conventional (2 °C for 24 h), ultra-rapid (− 20 °C for 3.5 h, 2 °C until 24 h) and slow chillings (12 °C for 7 h, 2 °C until 24 h) were compared. Total viable counts (TVC), weight losses, and pH and temperature falls were recorded on carcasses. Meat colour, water holding capacity (WHC), Warner-Bratzler shear force, sarcomere length and sensory analysis were evaluated in M. longissimus. Ultra-rapid treatment reduced TVC and weight losses. The pH decline was faster in slow chilled carcasses than in faster chilled carcasses. No significant differences were found for colour and WHC. Slow treatment carcasses showed significantly lower shear force and higher sarcomere length. In the sensory analysis, tasters also rated the early post mortem slow-treated meat as more tender, less fibrous and chewy. Therefore, delay chilling in suckling lamb carcasses made it possible to obtain meat with better organoleptic characteristics, without affecting weight loss or hygienic quality.     

Fluorimetric detection of protoporphyrins as an indicator for quality monitoring of fresh intact pork meat

In fresh meat production fast and non-destructive quality monitoring along the distribution chain is a key aspect to guaranteeing high quality and safe products for consumption. The applicability of fluorescence spectroscopy using protoporphyrins as indicators for meat ageing was investigated. Porcine musculus longissimus dorsi (MLD) was stored in slices over 20 days at 5 and 12 °C and measured every day with an excitation of 420 nm and an emission range of 550–750 nm. Additionally, pH, drip loss and colour were examined to assess possible correlations.The obtained spectra of the MLD showed an increase in three peaks at 592, 638 and 705 nm which could be reconstructed using the spectra of standard solutions of protoporphyrin IX (PP) and zinc protoporphyrin IX (ZnPP) or magnesium protoporphyrin (MgPP), respectively.Using principal component analysis (PCA) on the fluorescence spectral data, the meat slices stored at 5 °C showed differences in the fluorescence signal after the 10th day and 5th day when stored at 12 °C. An interrelationship between the additional analyses and the fluorescence intensities on these relevant days could not be established.In conclusion, the increase of ZnPP fluorescence due to temperature related changes of physiological meat properties is capable of serving as a quality indicator with regards to inadequate conditioning (e.g. during transportation and/or storage) of pork meat.     

Temperature shows greater impact on bovine Longissimus dorsi muscle glycogen debranching enzyme activity than does salt concentration

The degradation of glycogen progresses by the co-operation of two enzymes: glycogen phosphorylase (phosphorylase) and glycogen debranching enzyme (GDE). We studied the effect of temperature (4–42 °C) and salt concentration (0–3% NaCl) on bovine M. longissimus dorsi GDE activity. GDE activity (n = 4) decreased significantly with decreasing temperature from about 40–4 °C. GDE exhibited 52% activity at 25 °C and 11% at 4 °C compared to its optimum activity measured at 39 °C. In rapidly chilled meat, the reduction in GDE activity may substantially delay the rate of glycolysis. However, residual GDE activity at 4 °C seems sufficient to enable the attainment of normal ultimate pH if the available time is long enough. An increase in salt concentration from 0% to 2% and to 3% induced a significant (P < 0.001) increase in the ultimate pH of ground bovine meat (n = 6), but showed no effect on GDE activity.     

Growth of Listeria Monocytogenes in Traditional Austrian Meat Jelly Products

Individual components of a traditional meat jelly (cooked meat chunks, gelatin and preboiled vegetable) with differences in pH and a_w can constitute a niche for the multiplication of Listeria. Listeria monocytogenes counts remained stable in jelly over 21 days at 2 and 8 °C, whereas in meat and vegetables, a >1 log₁₀ unit increase was observed after 7 days at 2 °C (or >5 log₁₀ at 8 °C). In the composed product, Listeria numbers remained stable at 2 °C (21 days), but increased more than 1 log₁₀ during 7 days at 8 °C. Improving safety of jellied meat by lowering pH is discussed.     

Direct infusion of nitrite into meat batter by atmospheric pressure plasma treatment

This study investigated the influence of direct atmospheric pressure plasma (APP) treatment on nitrite levels and physiochemical quality of meat batter during the mixing process. A compact APP system was developed for installation on top of a food mixer. Meat batter composed of pork, water and sodium chloride (80:20:1, w/w/w) was treated with APP during mixing. Plasma treatment gradually increased the temperature of meat batter over 60 min from 0.2 °C to 20 °C. Total aerobic bacterial count of meat batter was not influenced by plasma treatment for 30 min (p > 0.05). The nitrite level in meat batter increased steadily with increasing plasma treatment duration (p < 0.05), reaching 65.96 ppm at 30 min. Consequently, the CIE a*- and b*-values of cooked meat batter gradually increased and decreased, respectively, as the time of plasma treatment increased. According to the results, direct APP treatment can replace nitrite addition in cured meat processing.     

Heat transfer modeling of chicken cooking in hot water

To calculate the slowest heating point and optimum cooking time of whole chicken cooking in hot water, a 2-dimensional heat transfer model was developed to predict temperature profile and history of the chicken cooked in hot water at 85, 90 and 95 °C. Chickens were divided into 12 sections and the heat transfer model was applied to each cross section. These models were solved with an I-DEAS program. Specific heat and thermal conductivity were measured at temperatures ranging from 25 to 95 °C. The temperature of chicken did not significantly affect the thermal properties. The average values of specific heat of white and dark meats were 3.521 and 3.654 kJ/(kg K), respectively, and the average thermal conductivity values were 0.5093 and 0.4930 W/(m K), respectively. The model was validated against experimental results, and provided an average root mean square error of 2.8 °C. Temperature distributions showed that the slowest heating point was deep in the breast part of the second cross section (3.6 cm far from shoulder) at the symmetric line of the chicken, around 2.1–2.5 cm deep from breast skin. For food safety consideration, the recommended cooking times, for whole chickens in weight range of 2.3–3.2 kg with different initial temperatures (5–30 °C), were around 74–84, 64–74 and 57–67 min for cooking temperatures of 85, 90, and 95 °C, respectively.     

Effect of very fast chilling and aging time on ultra-structure and meat quality characteristics of Chinese Yellow cattle M. Longissimus lumborum

Objectives of the current study were to evaluate meat ultra-structure and tenderness variation at different chilling regimes and aging times. Hot boned longissimus lumborum of 18 Chinese crossbred cattle were divided into 4 portions per side. One portion underwent very fast chilling (VFC, at − 21 °C to achieve core temperature of 0 °C, then transferred to another incubator at 2 °C), whereas other treatments were held at 14, 7 and 0 °C for 10 h postmortem, respectively. At 10 h postmortem, all muscles were vacuum aged at 2 °C for 21 d. Cold shortened muscles had greatest absolute amount of tenderization during aging. VFC caused lowest sarcomere length, with super-contractions, ruptured Z-lines and myofibril cleavage, but improved myofibril fragmentation index (MFI), with no significant negative effect on toughness. Overall, aging improved the meat quality of cold shortened beef. Moreover, it should be prudent in some applications to apply VFC to excised muscles from a food safety perspective, and to improve tenderness compared to cold-shortened muscles.     

Effect of high pressure,temperature, and storage on the color of porcine longissimus dorsi

The color of pork longissimus dorsi high pressure (HP) treated at 200 to 800 MPa at 5 and 20 °C for 10 min was determined to a high degree by pressure level and to a lesser degree by temperature. Severe color changes appeared up to a threshold pressure at 400 MPa. HP treatment at 20 °C compared to 5 °C resulted in meat, which was less red and slightly lighter. Storage at 2 °C for 6 days had no effect on lightness due to no further protein denaturation, but meat HP treated above 300 MPa became significantly less red and more yellow within the first day of storage. Reflectance spectra showed that a short-lived ferrohemochrome myoglobin species was formed during HP treatment at 300 to 800, but transformed into a brown, ferric form of the pigment within the first day of storage. This explains the observed changes in the redness and yellowness after one day of storage.