Effect of marinating time and low pH on marinade performance and sensory acceptability of poultry meat

The effects of marinating time (30, 60, 120 and 180 min) and acidic marinade pH (3.0, 3.2, 3.4, 3.6, 3.8, 4.0 and 4.2) on the instrumental and sensory properties of cooked Chinese-style marinated chicken were investigated. With increasing marinating time up to 180 min, a significant (P < 0.05) increase in surface redness (a∗ value) and the dark pink sensory attribute was observed, along with a corresponding decrease in lightness (L∗ value) and colour penetration. Increased marinating times of 120–180 min were found to produce more acceptable end products with increased scores for colour, aroma and flavour attributes. Marinade uptake was greater at higher marinade pH levels of 3.8, 4.0 and 4.2, with the highest marinade uptake (3.34%) recorded at pH 4.0. As changes to core meat pH were not observed, the effect of marinating time (up to 180 min) and marinade pH on the instrumental and sensory properties of Chinese-style marinated chicken were located principally at the surface of samples. Consumers considered surface colour as contributing to acceptability of marinated chicken to a greater degree compared to colour penetration.     

Effects of skin and grilling method on formation of heterocyclic amines in chicken pectoralis superficialis muscle

Mutagenic heterocyclic amines (HAs) originate in processed proteinaceous foods. The effects of the presence of skin (with vs. without) and of grilling method (two plate vs. infrared) on the content of HAs in grilled chicken pectoralis superficialis muscle (temperature, 220 °C) were investigated. HA precursors (creatine, creatinine, free amino acids and carbohydrates) and HAs of these raw and grilled breast muscles were determined. The muscles originated from 24 birds of either sex (provenance Ross; aged 40-45 days). The HA content was determined in homogenates of the upper and lower surface slices of the grilled muscles (T_i = 82 °C). A higher content of total free amino acids was seen for the muscle (27.1 mmol kg⁻¹ raw meat) than for the skin (21.7 mmol kg⁻¹ raw meat). The creatine, creatinine and carbohydrate levels in the skin were below the limits of detection. The contents of creatine (31.8-38.7 mmol kg⁻¹) and creatinine (0.24-0.33 mmol kg⁻¹) in the breast muscle were determined. Relatively high levels were seen for glucose (23 mmol kg⁻¹ raw meat) and fructose (10 mmol kg⁻¹ raw meat) in the muscle, with other sugars present at low levels (<2 mmol kg⁻¹ raw meat). For the chicken muscle grilled on a two-plate grill, the contents of total HAs (PhIP, MeIQx, DiMeIQx, Harman and Norharman) were lower with the skin in place than in the muscle grilled without the skin (3.5 μg kg⁻¹vs. 4.8 μg kg⁻¹). Also, during infrared grilling with the skin, lower amounts of HAs were formed than with grilling on the two-plate grill (2.4 μg kg⁻¹vs. 3.5 μg kg⁻¹). On average, the infrared-grilled samples with skin contained 3-fold more total HAs than similar samples without the skin (2.4 μg kg⁻¹vs. 0.8 μg kg⁻¹), with the highest levels seen for PhIP and MeIQx.     

Mutagenic heterocyclic amine content in thermally processed offal products

Heterocyclic amines (HAs) are potent mutagens formed during heat-processing of proteinaceous food. PhIP is the most ubiquitous and abundant mutagenic HA. In this study several offal products (beef liver, lamb kidney and beef tongue) have been thermally processed and analysed for HAs for the first time. Norharman and harman were the amines most abundant, found at concentrations below 2 ng g⁻¹. PhIP was only formed up to 0.12 ng g⁻¹. Among the rest of HAs analysed, only DMIP, MeIQx and 4,8-DiMeIQx were detectable in cooked kidney and tongue up to 0.25 ng g⁻¹. The influence of cooking additives on HAs formation was evaluated, finding higher levels of norharman and harman, up to 8.87 ng g⁻¹, in liver processed with additives, whereas similar levels of the rest of HAs were found in these samples. The low amounts of HAs found after the prolonged thermal treatments over 200 °C indicates that offal products are among the types of meat that produce lowest exposure to HA.     

Efficacies of soy sauce and wine base marinades for controlling spoilage of raw beef

Fresh beef slices were marinated by immersion in marinades based on soy sauce without (SB) or with lactic acid (SBLA) or red wine base without (WB) or with 0.5% v/v oregano essential oil (WBO). For control samples (immersed in saline), a mean increase of 0.9log CFU/cm² in total viable counts (TVCs) occurred during the 24 h treatment. During marination with WB and SB, mean TVC decreased by 0.7 and 0.3log CFU/cm², respectively. The mean decrease in TVC for samples marinated in WBO or SBLA was 1.2log CFU/cm². Subsequent storage of beef resulted in a rapid increase of TVC in control samples, to ≥9.5log CFU/cm² after 8 days at 5 °C or 3 days at 15 °C. Significant (P < 0.05) microbial growth occurred in marinated samples stored at 5 °C. During storage at 15 °C TVC increased in only WB samples but the final numbers of 5.9log CFU/cm² were significantly lower (P < 0.05) than the numbers in the control. Results similar to those for TVC were observed for Pseudomonas spp. All marinades also gave meat with significant lower TBARS values than the controls. There were no significant differences (P > 0.05) in the toughness of the marinated samples compared to the control, except for SBLA samples which had significantly higher (P < 0.05) shear force values. Marination with soy sauce or red wine marinades can evidently control microbial spoilage and oxidation of meat.     

By-products from herbs essential oil production as ingredient in marinade for turkey thighs

Herb decoctions—the aqueous extract of rosemary, sage and thyme, left as by-product after steam distillation of essential oils, were investigated as a source of antioxidants in marinades for turkey thigh meat. Lipid oxidation after marinating, cooking and chill storage (warmed over flavour, WOF) was assessed by thiobarbituric acid-reactive substances (TBARS), GC-MS and sensory judgement on marinated and untreated meat. Results showed that marinating with herb decoctions, which exerted antioxidant activity (free radical scavenging), was an effective means of retarding lipid oxidation in raw and cooked meat. Meat from the rosemary marinade had the lowest TBARS values and volatile levels, while the control samples showed the highest values throughout the marinating, cooking and storage period. Oxidative changes in meat marinated with thyme and sage were significantly more advanced than in meat marinated with rosemary decoction. The partial least squares regression (PLS-R) showed that control samples were strongly related to the oxidation variables (volatiles, TBARS, rancidity) while the marinated meat had high scores for spicy and acidic odour and flavour. Results indicated that antioxidants contained in herb decoction, could be exploited in marinades to prevent rancidity in stored, heat-treated turkey meat products.     

Ohmic cooking of whole beef muscle — Evaluation of the impact of a novel rapid ohmic cooking method on product quality

Cylindrical cores of beef semitendinosus (500 g) were cooked in a combined ohmic/convection heating system to low (72 °C, LTLT) and high (95 °C, HTST) target end-point temperatures. A control was also cooked to an end-point temperature of 72 °C at the coldest point. Microbial challenge studies on a model meat matrix confirmed product safety. Hunter L-values showed that ohmically heated meat had significantly (p < 0.05) lighter surface-colours (63.05 (LTLT) and 62.26 (HTST)) relative to the control (56.85). No significant texture differences (p ≥ 0.05) were suggested by Warner–Bratzler peak load values (34.09, 36.37 vs. 35.19 N). Cook loss was significantly (p < 0.05) lower for LTLT samples (29.3%) compared to the other meats (36.3 and 33.8%). Sensory studies largely confirmed these observations. Cook values were lower for LTLT (3.05) while HTST and the control were more comparable (6.09 and 7.71, respectively). These results demonstrate considerable potential for this application of ohmic heating for whole meats.     

High pressure induced changes on sarcoplasmic protein fraction and quality indicators

The combined effect of pressure and mild temperature treatments on bovine sarcoplasmic proteins and quality parameters was assessed. M. longissimus dorsi samples were pressurised in a range of 200–600 MPa and 10–30 °C. High Pressure Processing (HPP) induced a reduction of protein solubility (p < 0.001) compared to non-treated controls (NT), more pronounced above 200 MPa. HPP at pressures higher than 200 MPa induced a strong modification (p < 0.001) of meat colour and a reduction of water holding capacity (WHC). SDS–PAGE analysis demonstrated that HPP significantly modified the composition of the sarcoplasmic protein fraction. The pressurisation temperature mainly affected protein solubility and colour; a smaller effect was observed on protein profiles. Significant correlations (p < 0.001) between sarcoplasmic protein solubility and both expressible moisture (r = −0.78) and colour parameters (r = −0.81 to −0.91) suggest that pressure induced denaturation of sarcoplasmic proteins could influence to some extent WHC and colour modifications of beef. Changes in protein band intensities were also significantly correlated with protein solubility, meat lightness and expressible moisture. These results describe the changes induced by HPP on sarcoplasmic proteins and confirm a relationship between modification of the sarcoplasmic protein fraction and alteration of meat quality characteristics.     

The use of green tea (Camellia sinensis) leaf flavan-3-ol composition in predicting plain black tea quality potential

Reliable and quantifiable green leaf parameters for predicting black tea quality potential of tea bushes at the single bush stage are necessary to shorten tea breeding and clonal selection programmes. Green leaf flavan-3-ols (catechins) and plain black tea quality of 11 popular Kenyan clones were determined. The individual green leaf flavan-3-ols, and all the black tea quality parameters and sensory evaluations, except total flavan-3-ols were significantly different. The green leaf epigallocatechin gallate (EGCg) levels significantly correlated with black tea total theaflavin (r = 0.749, P ? 0.007), liquor brightness (r = 0.898, P ? 0.0001) levels and Taster B (r = 0.595, P ? 0.051) sensory evaluations, and negatively with thearubigins (r = −0.652, P ? 0.027), while green leaf epicatechin (EC) levels correlated positively with thearubigins (r = 0.694, P ? 0.016) and negatively with theaflavin digallate equivalent (r = −0.751, P ? 0.007), and sensory evaluation by Taster A (r = −0.785, P ? 0.003) and Taster B (r = −0.679, P ? 0.020). Thus, high levels of EGCg and low levels of EC in tea green leaf can be used as indicators of plain black tea quality potential of tea plants. The sum of gallated flavan-3-ols correlated significantly and positively with theaflavin digallate equivalent (r = 0.669, P ? 0.022) levels, but negatively correlated with the black tea thearubigins (r = −0.582, P ? 0.052). The sum of trihydroxyflavan-3-ols (gallocatechins) positively correlated with brightness (r = 0.750, P ? 0.007), and sensory evaluation by Taster A (r = 0.656, P ? 0.026), but negatively with thearubigins (r = −0.641, P ? 0.031). However, the sum of dihydroxyflavan-3-ols (simple catechins) correlated positively with thearubigins (r = 0.716, P ? 0.012) and negatively with total theaflavins (r = −0.6694, P ? 0.022), theaflavin digallate equivalent (r = −0.631, P ? 0.035), brightness (r = −0.843, P ? 0.001), Taster A (r = −0.775, P ? 0.004) and Taster B (r = −0.638, P ? 0.032) sensory evaluation. The ratios of trihydroxyflavan-3-ols to dihydroxyflavan-3-ols correlated positively with brightness (r = 0.678, P ? 0.020) and sensory evaluation of Taster A (r = 0.667, P ? 0.023), but negatively with thearubigins (r = −0.697, P ? 0.015). In addition to green leaf high levels of EGCg and low levels of EC, high levels of the sum of gallated catechins, trihydroxyflavan-3-ols, and the ratio of trihydroxyflavan-3-ols to dihydroxyflavan-3-ols are parameters in green tea leaf that may be used in predicting plain black tea quality potential of Kenyan tea clones.     

A note on the relationships between cured-cooked and dry-cured ham processing yields

Right and left hams from 353 pigs slaughtered at around 100 kg body weight were processed into cured-cooked hams and dry-cured hams, respectively. Weights and yields at various stages of each process, carcass lean content and fresh meat quality traits were registered. Technological yield of cured-cooked processing (saleable cooked ham weight/defatted–deboned fresh ham weight) was more closely correlated to ultimate pH (r = 0.51, p < 0.001) than to carcass leanness (r = −0.13, p < 0.05) whereas the reverse situation – r = 0.15 (p < 0.01) and r = −0.62 (p < 0.001), respectively – was found for technological yield of dry-cured processing (saleable dry ham weight/trimmed fresh ham weight). The correlation between the two technological yields was significantly positive but of fairly moderate magnitude (r = 0.36). The correlation between the overall yields (saleable processed ham weight/entire fresh ham weight) of the two processes revealed to be very close to zero (r = −0.01).     

Effects of ageing and low internal temperature of grilling on the formation of heterocyclic amines in beef Longissimus dorsi muscle

The mutagenic heterocyclic amines (HAs) originate in processed proteinaceous food. The effects of ageing (non-aged - i.e. 24 h post mortem vs. 14 and 28 days post mortem kept at 1 °C) and final internal temperature on cooking (T_i, 65 and 80 °C) on the content of HAs in grilled steaks (two-plated grill, temperature of 220 °C) were studied. HA precursors (creatine, creatinine, and free amino acids) and ageing indicators, such as instrumentally measured colour values, pH_ultimate values and length of myofibrilar fragments on raw and cutting values on grilled beef Longissimus dorsi muscles were determined. The muscles originated from eight commercially slaughtered Simmental bulls, 19-20 months old. The content of HAs was determined by a solid-phase extraction procedure. Meat ageing is accompanied by large changes in the chemical composition and structure of muscle tissues. In general, all the ageing indicators and precursors of HAs were influenced by ageing time at the 5% level or less. Creatine content declined significantly (non-aged: 6.00 mg g⁻¹, 14 days: 5.82 mg g⁻¹, and 28 days: 5.55 mg g⁻¹) and creatinine increased with days of ageing (non-aged: 0.19 mg g⁻¹, 14 days: 0.24 mg g⁻¹, and 28 days: 0.26 mg g⁻¹). Higher contents of total free amino acids were determined after 14 and 28 days of storage (28.18 μmol g⁻¹ and 37.59 μmol g⁻¹) than in non-aged beef (19.00 μmol g⁻¹). In this study, two HAs were determined: MeIQx (2-amino-3,8-dimethyl-imidazo[4,5-f]quinoxaline) and PhIP (2—amino-1-methyl-6-phenylimidazo-[4,5-b]pyridine). The content of HAs increases with ageing. At lower T_i, more MeIQx was formed; at higher T_i, more PhIP was formed. MeIQx was present in all samples while PhIP was found only in samples grilled to higher T_i. Samples treated to T_i = 80 °C generally contained less HAs (non-aged meat: 0.20 ng g⁻¹, 14 days: 0.26 ng g⁻¹, and 28 days: 0.28 ng g⁻¹) than samples treated to T_i = 65 °C (non-aged meat: 0.19 ng g⁻¹, 14 days: 0.36 ng g⁻¹, and 28 days: 0.39 ng g⁻¹) on account of MeIQx thermolability.     

Characterization of anthocyanins in Kenyan teas: Extraction and identification

Characterization and quantification of anthocyanins in selected tea cultivars processed into black (aerated) and green (unaerated) tea products was carried out in this study. The anthocyanins were extracted from tea products processed from a number of newly bred purple leaf coloured Kenyan tea cultivars (Camellia sinensis) using acidified methanol/HCl (99:1 v/v). Extracted anthocyanins were purified by C₁₈ solid phase extraction (SPE) catridges and characterised by HPLC-UV-Visible. They were identified according to their HPLC retention times, elution order and comparison with authentic standards that were available. Total monomeric anthocyanins were determined by the pH-differential method. Although the tea cultivars gave different yields of anthocyanins, the unaerated (green) teas had significantly (p ? 0.05) higher anthocyanin content than the aerated (black) teas. This was attributed to the degradation of anthocyanins by polyphenol oxidase products (catechin O-quinones) formed during the auto-oxidation (fermentation) process of black tea manufacture. Of the six most common natural anthocyanidins, five were identified in the purified extracts from purple leaf coloured tea, in both aerated (black) and unaerated (green) teas namely; delphinidin, cyanidin, pelargonidin, peonidin and malvidin. The most predominant anthocyanidin was malvidin in both tea products. In addition, two anthocyanins namely, cyanidin-3-O-galactoside and cyanidin-3-O-glucoside were also identified. Tea catechins were also identified in the tea products derived from the purple coloured tea cultivars namely, epigallocatechin (EGC), catechin (+C), epicatechin (EC), epigallocatechin gallate (EGCG), and epicatechin gallate (ECG). Correlation between the total catechins versus the total anthocyanins and anthocyanin concentration in unaerated teas revealed significant negative correlations (r = −0.723^∗ and r = −0.743^∗∗, p ? 0.05 and p ? 0.01, respectively). However, in aerated (black) tea the correlations were insignificant (r = −0.182 and r = −0.241, p > 0.05).     

Fat oxidation in freeze-dried grouper during storage at different temperatures and moisture contents

The effects of moisture content levels and storage temperature on the lipid oxidation in freeze-dried grouper were studied. Three trends were observed in the changes of PV (peroxide value) depending on the moisture content and storage temperature. An exponential rise of PV was observed (p < 0.05) at lower temperatures (−20 °C and 5 °C for samples at moisture 5 g/100 g; and −20 °C for samples at moisture 20 g/100 g). At temperatures 25 °C for samples at moisture 5 g /100 g, and 5 and 25 °C for samples at 20 g moisture/100 g peaks of PV were observed (p < 0.05). At higher temperatures (40 °C for both moisture content levels) an exponential decay instead of increase were observed (p < 0.05). Moisture content levels had no significant effect (p > 0.05) on PV stored at temperature of −40 °C. The monolayer moisture for freeze-dried grouper was estimated as 6.2 g/100 g dry solids using BET-isotherm. Differential scanning calorimetry (DSC and modulated DSC) thermogram line showed two shifts (i.e. glass transition) and two endothermic peaks, one for melting of oil and another for decomposition. The validity of the water activity and glass transition concepts were evaluated. It is concluded that glass transition concept may be used to explain the process more adequately.     

Chemical quality and sensory attributes of marinated Pacific saury (Cololabis saira) during vacuum-packaged storage at 4 °C

This study was carried out to evaluate the chemical changes and sensory attributes of Pacific saury (Cololabis saira), brined (12% NaCl brine solution) or marinated (12% NaCl + 2% acetic acid; or 12% NaCl + 3% acetic acid solutions) followed by vacuum-packaging and storage at 4 °C for 90 days. The chemical analysis revealed a significant reduction in the pH value, total volatile bases nitrogen (TVBN), and trimethylamine (TMA) contents in marinated versus brined fillets. Lipid oxidation, as indicated by the 2-thiobarbituric acid (TBA) values, was significantly delayed in marinated fillets in comparison with the brined fillets. The growth rate of psychrotrophic bacteria was significantly (P < 0.05) reduced in marinated versus brined fillets. No significant differences were detected for the sensory attributes between the two marinating conditions although the overall acceptability was significantly higher in marinated versus brined fish. Both conditions of the marinating process resulted in an extension of the shelf life of the product to more than 90 days versus only 60 days for the control brined fillets. The study concluded that marination of Pacific saury can delay the undesirable chemical changes, retard lipid oxidation, improve the sensory attributes and extend the shelf life of the product during refrigerated storage.     

Relationship between the solubility,dosage and antioxidant capacity of carnosic acid in raw and cooked ground buffalo meat patties and chicken patties

Antioxidant capacity of oil soluble and water dispersible carnosic acid (CA) extracted from dried rosemary leaves using HPLC was evaluated at two different dosages (22.5 ppm vs 130 ppm) in raw and cooked ground buffalo meat patties and chicken patties. Irrespective of total phenolic content, CA extracts reduced (p < 0.05) the thiobarbituric acid reactive substances (TBARS) by 39%–47% and 37%–40% in cooked buffalo meat and chicken patties at lower dosage (22.5 ppm) relative to control samples. However, at higher dosage (130 ppm) the TBARS values were reduced (p < 0.05) by 86%–96% and 78%–87% in cooked buffalo meat and chicken patties compared to controls. The CA extracts were also effective in inhibiting (p < 0.05) peroxide value and free fatty acids in cooked buffalo meat and chicken patties. The CA extracts when used at higher dosage, were also effective in stabilizing raw buffalo meat color.     

Effects of freezing rates on starch retrogradation and textural properties of cooked rice during storage

The effects of freezing rates and storage temperatures on starch retrogradation and textural properties of cooked rice were evaluated. Cooked rice was frozen with different freezing rates and then stored at 4 °C for 14 days or −18 °C for up to 7 months. Starch retrogradation enthalpy (ΔH_r) of cooked rice was determined by a differential scanning calorimetry, and textural properties were determined by a texture analyser. The results showed that the ΔH_r and hardness values had a negative correlation with freezing rate, however, a positive correlation was found between adhesiveness and freezing rate. On the other hand, the advantages (lower hardness and higher adhesiveness, less starch retrogradaton) of cooked rice gained by rapid freezing, were lost quickly in the first 3 days of storage at 4 °C. However, rapid freezing combined with −18 °C frozen storage can effectively retard starch retrogradation and maintain the textural properties of cooked rice for at least 7 months. Therefore, high quality cooked rice can be produced by combined rapid freezing with frozen storage.     

Analysis of heterocyclic amines (HAs) in pan-fried pork meat and its gravy by liquid chromatography with diode array detection

Aminoazaarenes (heterocyclic amines, HAs) contents were investigated in pan-fried pork meat as well as in gravies generated during frying. The clean-up procedure included alkaline hydrolysis, tandem solid phase extraction on columns filled with Extrelut – diatomaceous earth, cation exchanger (propyl sulfonic acid) and chemically bounded phase – C₁₈. Identification and quantitative analysis of HAs fraction was carried out using a HPLC system with DAD-type detector. Separation was achieved by using TSK-gel ODS 80-T_M column and a mixture of 5% acetonitrile and 95% triethylamine phosphate buffer (pH 3.3) as a mobile phase. Six compounds were determined: 2-amino-1,6-dimethylimidazo[4,5-b]pyridine (DMIP), 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (8-MeIQx), 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx), 2-amino-1-methyl-6-phenyl-imidazo[4,5-b]pyridine (PhIP). Two types of dishes prepared at home according to common recipes used in Poland were investigated. The total content of aminoazaarenes determined in collar was 7.2 and in chop samples 18.0 ng g⁻¹ of cooked meat. The total contents of investigated HAs in gravy samples were 10.2 and 15.1 ng g⁻¹ of cooked meat for collars and chops, respectively.     

Effects of ohmic thawing on histological and textural properties of beef cuts

The changes in the histology and the texture of beef cuts during ohmic thawing were compared with those during conventional thawing method. The beef cut samples were thawed from −18 to 10 °C by applying different voltage gradients (10, 20 and 30 V/cm) during ohmic treatment whereas conventional thawing was applied at constant temperature (25 °C, 95% RH) in the controlled incubator. There were significant differences between the effects of thawing methods in terms of hardness, chewiness, gumminess of beef cut samples (p < 0.05). The sample treated ohmically at 30 V/cm voltage gradient was significantly different from the other thawed samples in terms of springiness, cohesiveness and resilience (p < 0.05). The change in the textural properties was explained by investigating the histological changes of beef cuts for both thawing method. Ohmic thawing provided the thawed meat sample having lower textural and histological changes rather than conventionally thawed ones.     

Effects of Kudoa spores,endogenous protease activity and frozen storage on cooked texture of minced Pacific hake (Merluccius productus)

The effects of Kudoa infection of Pacific hake (Merluccius productus) on endogenous protease activity and on cooked mince texture were investigated. Texture was significantly (p < 0.05) negatively correlated with spore counts as well as protease activity. Soft texture (maximum force <150 g) was observed in fish with 10⁴–10⁶Kudoa thyrsites spores g⁻¹ mince, compared to 10⁵–10⁸K. paniformis spores g⁻¹ mince, suggesting that especially for fish having lower infection levels, K. thyrsites may have a greater impact than K. paniformis on Pacific hake quality. Pre-incubation for 15 min at 52 °C prior to cooking resulted in softer texture in some samples due to endogenous proteolytic action. This pre-incubation effect was not consistently observed in fish held 6 months or longer at −25 °C or after freeze-thaw cycling, which may be explained by an opposing toughening effect attributed to protein denaturation and aggregation during prolonged or abusive frozen storage.     

Physico-chemical, textural and structural characteristics of sous-vide cooked pork cheeks as affected by vacuum, cooking temperature, and cooking time

This paper describes the influence of different factors on sous-vide cooked pork. Pork cheeks were cooked at different combinations of temperature (60 °C or 80 °C), time (5 or 12 h) and vacuum (vacuum or air packaged). Weight losses were lower and moisture content higher in samples cooked for a shorter time (P = 0.054) and at a lower temperature (P < 0.001). Samples cooked at 60 °C showed more lightness (L*) and redness (a*) (P < 0.001). Lipid oxidation showed an interaction between cooking time and temperature (P = 0.007), with higher TBARs values for samples cooked for 12 h at 60 °C and lower for those cooked for 12 h at 80 °C. Samples cooked at 80 °C for 12 h showed lower (P < 0.05) values for most textural parameters than all the other types of samples. Vacuum packaging showed no influence on any of the studied variables. For the treatments evaluated, cooking temperature × time combination seems to be more important than vacuum packaging in the textural and colour parameters of pork cheeks.     

Inhibitory effect of marinades with hibiscus extract on formation of heterocyclic aromatic amines and sensory quality of fried beef patties

Heterocyclic aromatic amines (HAA) are carcinogenic compounds found in the crust of fried meat. The objective was to examine the possibility of inhibiting HAA formation in fried beef patties by using marinades with different concentrations of hibiscus extract (Hibiscus sabdariffa) (0.2, 0.4, 0.6, 0.8 g/100 g). After frying, patties were analyzed for 15 different HAA by HPLC-analysis. Four HAA MeIQx (0.3–0.6 ng/g), PhIP (0.02–0.06 ng/g), co-mutagenic norharmane (0.4–0.7 ng/g), and harmane (0.8–1.1 ng/g) were found at low levels. The concentration of MeIQx was reduced by about 50% and 40% by applying marinades containing the highest amount of extract compared to sunflower oil and control marinade, respectively. The antioxidant capacity (TEAC-Assay/Folin–Ciocalteu-Assay) was determined as 0.9, 1.7, 2.6 and 3.5 μmol Trolox antioxidant equivalents and total phenolic compounds were 49, 97, 146 and 195 μg/g marinade. In sensory ranking tests, marinated and fried patties were not significantly different (p > 0.05) to control samples.