Effect of different cooking methods on lipid oxidation and formation of volatile compounds in foal meat

The influence of four different cooking methods (roasting, grilling, microwaving and frying) on cooking loss, lipid oxidation and volatile profile of foal meat was studied. Cooking loss were significantly (P < 0.001) affected by thermal treatment, being higher (32.5%) after microwaving and lower after grilling (22.5%) and frying (23.8%). As expected, all the cooking methods increased TBARs content, since high temperature during cooking causes increased oxidation in foal steaks, this increase was significantly (P < 0.001) higher when foal steaks were microwaved or roasted.     

Influence of thermal treatment on formation of volatile compounds,cooking loss and lipid oxidation in foal meat

The influence of four different cooking methods (roasting, grilling, microwaving baking and frying with olive oil) on volatile compounds profile (using solid phase microextraction coupled to GC–MS), lipid oxidation (by TBARs measurement) and cooking loss of foal meat was studied. Cooking losses were significantly (P < 0.001) affected by thermal treatment, being higher (29.9%) after microwaving and lower after grilling (19.1%) treatments. As expected, all the cooking methods increased TBARs content, since high temperature during cooking seems to cause an increase of the oxidation processes in foal steaks, being this increment significantly (P < 0.001) higher when foal steaks were roasted or microwaved.     

Effect of cooking methods on the formation of heterocyclic aromatic amines in chicken and duck breast

Heterocyclic aromatic amines (HAAs), potent mutagens/carcinogens, are pyrolysis formed during the cooking of meat and fish. In the present study, the effects of various cooking methods, pan-frying, deep-frying, charcoal grilling and roasting on the formation of HAAs in chicken breast and duck breast were studied. The various HAAs formed during cooking were isolated by solid-phase extraction and analyzed by high-performance liquid chromatography (HPLC). Results showed that chicken breast cooked by charcoal grilling contained the highest content of total HAAs, as high as 112 ng/g, followed by pan-fried duck breast (53.3 ng/g), charcoal grilled duck breast (32 ng/g), pan-fried chicken breast (27.4 ng/g), deep-fried chicken breast (21.3 ng/g), deep-fried duck breast (14 ng/g), roasted duck breast (7 ng/g) and roasted chicken breast (4 ng/g). For individual HAA, the most abundant HAA was 9H-pyrido-[4,3-b]indole (Norharman), which was detected in charcoal grilled chicken breast at content as high as 32.2 ng/g, followed by 1-methyl-9H-pyrido[4,3-b] indole (Harman) and 2-amino-1-methyl-6-phenylimidazo[4,5-f]pyridine(PhIP) at 32 and 31.1 ng/g in charcoal grilled chicken breast, respectively. The content of PhIP in pan-fried duck and chicken breast were 22 and 18.3 ng/g, respectively. Generally, the type and content of HAAs in cooked poultry meat varies with cooking method and cooking conditions.     

Grape seed extract as antioxidant in cooked, cold stored turkey meat

Efficiency of four concentrations of grape seed extract (0.0, 0.4, 0.8, and 1.6 g/kg) in retarding oxidative rancidity was tested with cooked turkey breast meat. Development in lipid oxidation during 13 days of refrigerated storage was evaluated by means of thiobarbituric acid-reactive substances (TBARS) and volatile compound formation. Hexanal, pentanal, octanal, 2-octenal, 1-octen-3-ol, 2-octen-1-ol, and 1-penten-3-ol showed high correlations (r>0.95) with TBARS values and could, therefore, serve as markers for the oxidation process in the cooked turkey breast meat. Supplementation of grape seed extract prior to cooking significantly improved oxidative stability of minced turkey meat during heat treatment and storage. The ability of grape seed extract to prevent lipid oxidation was concentration-dependent. Vacuum-packaging considerably improved oxidative stability of meat regardless of the low concentration of grape seed extract used. It appears that grape seed extract could be very effective in inhibiting lipid oxidation of cooked turkey meat during chill-storage.     

Effects of freezing temperature and duration of frozen storage on lipid and protein oxidation in chicken meat

This study examined the effects of freezing temperature and duration of frozen storage on lipid and protein oxidation in chicken leg and breast meat. The meat was frozen at three different temperatures (−7, −12 and −18 °C) and then stored at −18 °C for up to 6 months. A significant effect of frozen storage duration on lipid oxidation was detected in leg and breast meat, whereas freezing temperature had no significant effect. In leg meat, freezing at −7 °C had a significant impact on protein oxidation, measured as the increase in carbonyl groups and the decrease in total sulphydryl groups, after 3 months of frozen storage. Lipid and protein oxidation appeared to occur simultaneously in chicken meat during frozen storage and was more intense in leg meat than in breast meat.     

Effect of different cooking methods on lipid oxidation and formation of free cholesterol oxidation products (COPs) in Latissimus dorsi muscle of Iberian pigs

The aim of this work was to study the influence of different cooking methods (grilled (GR), fried (FP), microwave (MW) and roasted (RO)) on lipid oxidation and formation of free cholesterol oxidation products (COPs) of meat from Iberian pigs that have been fed on an intensive system. Moisture and total lipid content, TBARs, hexanal and COPs were measured in Latissimus dorsi muscle samples. Cooking did not produce changes in total lipid content in meat but induced significantly higher lipid oxidation (TBARs and hexanal values) (p < 0.001) and cholesterol oxidation (COPs) (p < 0.01). When the different cooking methods were studied, the grilled method was the least affected by lipid oxidation (TBARs and hexanal) compared to the others. There were no significant differences among different cooking methods on COPs values. The most abundant cholesterol oxides were both 7α-hydroxycholesterol and 7β-hydroxycholesterol in all groups studied.     

Suitability of saturated aldehydes as lipid oxidation markers in washed turkey meat

The aim of this study was to evaluate the suitability of saturated aldehydes as lipid oxidation markers in washed turkey muscle, by means of headspace solid phase microextraction-gas chromatography (HS-SPME-GC); the results were compared with the widely used thiobarbituric acid-reactive substances (TBARs) method. Changes in TBARs, propanal and hexanal concentrations were determined over time in a model system consisting of turkey muscle washed with a sodium phosphate buffer (pH 5.6). To stop oxidation from occurring during analysis, an antioxidant mixture (EDTA, trolox and propyl gallate) was added immediately before analyses. After antioxidant addition, propanal and TBARs concentrations did not increase during 8 h of further storage, while an unexpected decrease in hexanal was observed. To determine if aldehydes were interacting with washed turkey muscle, hexanal and propanal were added to either phosphate buffer or washed muscle and concentrations were monitored for 24 h. Neither propanal nor hexanal decreased in the phosphate buffer over time, but the headspace concentration of propanal and hexanal in washed turkey muscle were markedly lower (76% and 96%, respectively) at time zero and continued to decreased up to 24 h of storage. Because of this decrease in headspace aldehyde concentrations, TBARs were found to be a more sensitive and accurate marker of oxidative deterioration in washed turkey muscle.     

Aroma development in high pressure treated beef and chicken meat compared to raw and heat treated

Chicken breast and beef muscle were treated at 400 and 600 MPa for 15 min at 5 °C and compared to raw meat and a heated sample (100 °C for 15 min). Vacuum-packed beef meat with a smaller fraction of unsaturated fatty acids showed better oxidative stability during 14 days of cold storage, as shown by a low steady-state level of hydroperoxide values, than vacuum-packed chicken meat. Accordingly, the critical pressures of 400 MPa and 600 MPa for chicken breast and beef sirloin, respectively, were established. Volatiles released after opening of the meat bags or during storage of open meat bags, simulating consumer behaviour, were measured under conditions mimicking eating. Quantitative and olfactory analysis of pressurised meat gave a total of 46 flavour volatiles, mainly alcohols (11), aldehydes (15), and ketones (11), but all in low abundance after 14 days of storage. Overall, beef meat contained less volatiles and in lower abundance (factor of 5) compared to chicken meat. The most important odour active volatiles (GC-O) were well below the detection thresholds necessary to impart a perceivable off-flavour. Lipid oxidation was significantly accelerated during 24 h of cold storage in both cooked chicken and beef when exposed to oxygen, while the pressurised and oxygen-exposed chicken and beef meat remained stable. Pressure treatment of beef and chicken did not induce severe changes of their raw aroma profiles.     

Contents of biologically active polyamines in chicken meat,liver, heart and skin after slaughter and their changes during meat storage and cooking

Dietary polyamines, putrescine, spermidine (SPD) and spermine (SPM), participate in an array of important physiological roles, including tumour growth. Thus, reliable information on polyamine content in foods has been needed. We therefore determined polyamine contents in chilled chicken meat and giblets (n = 20) and skin (n = 10) 24 h after slaughter. The polyamines were determined, after extraction with perchloric acid, as dansyl derivatives, using an HPLC method. Mean SPD values were 4.8, 10.2, 11.4, 48.7 and 12.1 mg kg⁻¹ and SPM values were 36.8, 38.0, 24.3, 133 and 82.7 mg kg⁻¹ in breast, thigh, skin, liver and heart, respectively. Significant statistical correlations between SPD and SPM contents were observed in breast, thigh, skin and liver, whereas correlations were insignificant in heart. An increase of SPD and SPM was apparent in breasts and thighs stored at −18 °C for 6 months; however, it was significant only for SPM in thighs. The losses of both SPD and SPM were statistically insignificant during storage of aerobically packaged breasts up to 9 days at +2 °C. A significant decrease of SPM to about 60% of the initial contents was observed in both vacuum-packaged and in modified atmosphere (20% CO₂ and 80% O₂)-stored breasts on day 21 at +2 °C. For both SPD and SPM, roasting, grilling and frying of fresh breasts caused losses of about 40–60% of the initial contents (higher than boiling and stewing). Similarly, losses of SPM, due to roasting of breasts frozen for 3 or 6 months, were higher than those caused by stewing. Putrescine was detected only sporadically and at levels close to the detection limit of 1.0 mg kg⁻¹ (fresh matter).     

Effect of natural antioxidant combinations on lipid oxidation in cooked chicken meat during refrigerated storage

The effect of combinations of sage, oregano and honey on lipid oxidation in cooked chicken meat during refrigeration at 4°C for 96h was determined. Chicken samples (thigh and breast) were then separated into five groups: control; butylated hydroxytoluene; oregano+sage; oregano+sage+5%honey and oregano+sage+10%honey. Quantitative measurements of thiobarbituric acid reactive substances, conjugated dienes, hexanal, fatty acids, cholesterol and cholesterol oxides were used as indicators of lipid oxidation. Acceptability and preference were also evaluated. The effectiveness of the natural antioxidants for reducing the velocity of lipid oxidation in cooked chicken thigh and breast was demonstrated after 48 and 96h of refrigeration at 4°C. The treatments that presented the lowest hexanal values after 96h of refrigeration were oregano+sage+5%honey and oregano+sage+10%honey. Only traces of free cholesterol oxides were found (25-OH, 7-k, 7α-OH and 7β-OH). The natural antioxidants protected cooked chicken meat from oxidation processes and resulted in great acceptability.     

Effect of sage and garlic on lipid oxidation in high-pressure processed chicken meat

Sage was found to protect minced chicken breast processed with high hydrostatic pressure up to 800 MPa for 10 min against lipid oxidation during subsequent chilled storage for 2 weeks. Garlic showed prooxidative effects especially at moderate high pressure around 300 MPa, an effect partly counteracted by simultaneous addition of sage. From the rate of lipid oxidation, measured as thiobarbituric acid reactive substances, the apparent volume of activation for pressure-induced lipid oxidation during subsequent chilled storage was estimated, which showed that the prooxidative effect of garlic and pressure-induced lipid oxidation were additive. Based on electron spin resonance (ESR) spectroscopy radical formation was measured in pressurized lipid and aqueous phases of minced chicken thighs, and a high radical scavenging capacity of sage in the lipid phase was identified as most important for the protective effect of sage.     

The role of product familiarity and consumer involvement on liking and perceptions of fresh meat

The objective of this work was to compare consumer’s liking and perception of meat quality attributes as a function of their familiarity and involvement with fresh meat.Ninety-three meat consumers were classified on the basis of their familiarity with fresh meats. Socio-demographic differences between the clusters were found to relate to gender and age, and high familiarity (HF) consumers showed higher involvement with meat. HF consumers enjoyed consuming meat, and they associated a symbolic value to it. In addition, their liking ratings were higher than those of low familiarity (LF) consumers for both appearance and taste of three specific types of fresh meat over the course of product shelf-life. The perceived risks associated with meat consumption and product choice were similar between groups. Both consumer segments reported that the most important driver of fresh meat purchase is its appearance, while the role of extrinsic cues differed among the groups. The HF group needed more information when choosing meat. Regardless of familiarity level, liking was consistent with beef appearance as affected by storage, but the prediction of experienced sensory quality lacked consistency when the perceived intrinsic cue variation was not associated with meat freshness.     

肉蛋白烹调氧化及其对肉品与人体健康的影响

烹调加工会加剧蛋白质氧化,导致蛋白质结构、理化性质等发生变化,从而影响其功能特性与营养价值。本文介绍了肉类烹调过程中蛋白质氧化机制、表现形式,探讨了其对肉类感官品质与营养价值的影响及对人体健康的潜在危害,最后进行总结与展望。      

Wine industry residues extracts as natural antioxidants in raw and cooked chicken meat during frozen storage

The effect of Isabel (IGE) and Niagara (NGE) grape seed and peel extracts on lipid oxidation, instrumental colour, pH and sensory properties of raw and cooked processed chicken meat stored at -18°C for nine months was evaluated. The pH of raw and cooked samples was not affected by the addition of grape extracts. IGE and NGE were effective in inhibiting the lipid oxidation of raw and cooked chicken meat, with results comparable to synthetic antioxidants. The extracts caused alterations in colour, as evidenced by the instrumental (darkening and lower intensity of red and yellow colour) and sensory results of cooked samples. In the sensory evaluation of odour and flavour, IGE produced satisfactory results, which did not differ from synthetic antioxidants. These findings suggest that the IGE and NGE are effective in retarding lipid oxidation of raw and cooked chicken meat during frozen storage.     

Preliminary investigation on the relationship of Raman spectra of sheep meat with shear force and cooking loss

A prototype handheld Raman system was used as a rapid non-invasive optical device to measure raw sheep meat to estimate cooked meat tenderness and cooking loss. Raman measurements were conducted on m. longissimus thoracis et lumborum samples from two sheep flocks from two different origins which had been aged for five days at 3–4 °C before deep freezing and further analysis. The Raman data of 140 samples were correlated with shear force and cooking loss data using PLS regression. Both sample origins could be discriminated and separate correlation models yielded better correlations than the joint correlation model. For shear force, R² = 0.79 and R² = 0.86 were obtained for the two sites. Results for cooking loss were comparable: separate models yielded R² = 0.79 and R² = 0.83 for the two sites. The results show the potential usefulness of Raman spectra which can be recorded during meat processing for the prediction of quality traits such as tenderness and cooking loss.     

Comparison of lipid and protein oxidation,total iron content and fatty acid profile of conventional and organic pork

The aim of the research was to compare differences in lipid and protein oxidation, total iron content and fatty acid profile in pork loin obtained from organic and conventionally reared pigs. The samples of organic meat were taken from breeding certified by the polish certifying body according to the Council Regulation (EC) no 834/2007 on organic production and labelling of organic products. The meat samples were examined at the following times post‐mortem: 2, 4, 7 days. Measurements of lipid oxidation showed that the organic meat samples were characterised by lower TBARS values during whole storage period (0.78–0.81 mg kg^?1) compared with those of conventional system production (0.95–0.99 mg kg^?1). Results of protein oxidation measurements of the organic meat sample were significantly lower (0.43 nmol mg^?1 protein) at the beginning of experiment than those for the conventional meat sample (0.66 nmol mg^?1 protein). It was also indicated that the production system had no effect on iron content and myoglobin oxidation during storage. In conclusion, obtained results pointed out that the organic pig meat was characterised by higher lipid stability during the whole storage time compared with meat from conventional production system.     

Effects of salt and ammonium hydroxide on the quality of ground buffalo meat

The objective of this study was to evaluate the effects of ammonium hydroxide (AH) and sodium chloride on the quality of ground buffalo meat patties. Ground buffalo meat was treated with distilled water (control), 0.5% v/w AH, 1.0% v/w AH, 2.0% v/w AH and 1.0% w/w sodium chloride was added for all the samples. Treatment with AH increased (P<0.05) the pH and water holding capacity (WHC) of ground buffalo meat patties during storage relative to their controls. Hunterlab a* (redness) and chroma values increased (P<0.05) and hue decreased (P<0.05) in all AH treated samples in comparison to controls during storage. Ammonium hydroxide significantly (P<0.05) inhibited metmyoglobin formation compared to control after 3rd day of storage. There was a significant (P<0.05) reduction in thiobarbituric acid reactive substances (TBARS) values in all AH treated samples compared to control throughout storage. These results indicate the potential antioxidant and myoglobin redox stabilizing effect of AH in ground buffalo meat patties.     

Physicochemical and microbiological characteristics of biltong,a traditional salted dried meat of South Africa

The microbiological and physicochemical characteristics of several commercial beef, kudu and springbok biltong samples from South Africa were assessed in this study. Analysis of samples allowed their differentiation into ‘dry’ and ‘moist’ samples. Dry biltong showed low moisture content (21.5–25.3 g/100 g), a low water activity (0.65–0.68) and a high salt content (5.5–7.9 g/100 g), while moist biltong showed a higher moisture content (35.1–42.8 g/100 g), a higher water activity (0.85 to 0.89) and a lower salt content (3.8–5.6 g/100 g). The pH value did not vary significantly between both groups (5.00–6.26). The results showed that dry biltong presented a low total plate count (TPC) content, a high level of lactic acid bacteria (LAB) and a high level of d-lactic acid as compared to moist biltong. These results suggest that dry biltong complies with the standard hygienic quality (TPC < 7 log cfu/g in agreement with the Food Standards Agency), while moist biltong samples generally showed a low content of d-lactic acid and a low ratio LAB/TPC.     

烘烤条件对鸭肉脯挥发性风味物质的影响

以鸭肉为原料,研究烘烤加工条件对鸭肉脯挥发性风味物质的影响,从而确定最佳的烘烤条件,采用顶空固相微萃取(HS-SPME)和气质联用(GC-MS)技术检测分析鸭肉脯中挥发性风味物质,结果表明,鸭肉脯的最优烘烤条件为:低温脱水时间3h,低温脱水温度60℃,高温熟化时间6min,高温熟化温度180℃,在此条件下加工的鸭肉脯风味最佳且最浓郁。     

食用胶对鸭肉脯保藏期间挥发性风味物质变化的研究

随着保藏时间的延长鸭肉脯中的挥发性风味物质会逐渐挥发,造成鸭肉脯的风味减淡,影响鸭肉脯的品质,因此在加工的过程中需要采取措施以保持鸭肉脯在保藏过程中的挥发性风味物质的稳定性,以鸭肉为原料,研究了鸭肉脯在加工过程中添加黄原胶、卡拉胶、阿拉伯胶和魔芋胶对鸭肉脯保藏期间挥发性风味物质变化规律的影响。采用顶空固相微萃取技术和气相色谱质谱联用检测方(HS-SPEM-GC-MS)对鸭肉脯的挥发性风味物质进行萃取和检测,研究结果表明,添加食用胶后可以减缓鸭肉脯挥发性风味物质总含量的挥发速度,有效的保持了鸭肉脯的挥发性风味物质,同时添加食用胶对鸭肉脯中主要挥发性风味物质中的壬醛、草蒿脑等起到较好的保持作用,从而有利于延长鸭肉脯的保藏时间风味稳定性。