Change of fatty acid esters of MCPD and glycidol during restaurant deep frying of fish nuggets and their correlations with total polar compounds

This study examined the fatty acid esters of 2-monochloropropane-1,2-diol (2-MCPD), 3-monochloropropane-1,2-diol (3-MCPD) and glycidyl esters (GEs) in frying oils during fish nuggets deep frying. The 3-MCPD esters significantly increased in the first 12 h and then decreased, whereas 2-MCPD esters increased to a maximum at 24 h (0.69–0.81 mg kg⁻¹) and then decreased. The GEs decreased with frying time and degraded to approximately 0.05 mg kg⁻¹ after 36 h in all frying oils. The correlation results showed that the 3-MCPD esters had a positive correlation with 2-MCPD esters (R = 0.910), so 3-MCPD esters could be an indicator of the presence of MCPD esters in frying oils. Strong correlations were found between MCPD esters and the peroxide values and p-anisidine values, indicating that changes in MCPD esters may be related to oil oxidation. These results may improve our understanding of MCPD esters and GEs in frying oils and find ways to control them during frying.     

Amino Acid and Vitamin Composition of Raw and Cooked Horse Mackerel

Amino acid, vitamin (A, E, B₁, B₂, B₃ and B₆), and proximate composition were determined in raw and cooked horse mackerel. The changes in amino acid, vitamin, and proximate content were found to be significant for all cooking methods (frying, grilling, and steaming). Cooking did in general significantly increase the contents of essential, semi-essential, and other amino acids compared to raw fish species. Amino acid contents of grilled mackerel were significantly higher (p < 0.05) than those found in fried and steamed mackerel. The A, E, B₂, and B₆ vitamin content of fried horse mackerel was found to be significantly (p < 0.05) higher than the grilled and steamed samples. The B₁ content of steamed and B₃ content of grilled were found higher than the other cooked samples. Moisture, protein, fat, ash, and carbohydrate contents of cooked fish ranged between 56.52% to 61.34%, 20.79% and 23.93%, 13.44% and 19.61%, 1.70% and 2.47%, and 1.02% and 4.36 %, respectively. Fried fish had intermediate fat values, while grilled and steamed fishes had a comparatively low value.     

大豆油吸附脱色过程氯离子含量变化及对脱臭油中 3-氯丙醇酯和缩水甘油酯的影响

参照土壤中氯离子检测方法,对常见油脂脱色吸附剂中氯离子的超声提取时间进行优化,并对其氯离子含量进行检测。利用常见的吸附剂对大豆油进行吸附脱色,检测吸附脱色前后油脂中氯离子含量,对不同吸附剂脱色后的油脂进行蒸馏脱臭,检测脱臭油中3-氯丙醇酯(3-MCPD酯)和缩水甘油酯(GEs)含量,分析研究不同吸附剂对油脂吸附脱色过程氯离子含量的影响以及对脱臭油中3-MCPD酯和GEs的影响。结果表明:吸附剂中氯离子的最佳超声提取时间为30 min,10个吸附剂样品中氯离子含量为11. 93～187. 881 mg/kg,差异很大;几种吸附剂在油脂吸附脱色过程对氯离子有不同程度的脱除作用,其中脱除效果最好的YS-900活性炭能使油脂中氯离子含量降低83. 21%。对比未进行吸附脱色处理的大豆油,经吸附脱色的大豆油再经脱臭后3-MCPD酯与GEs生成量均有所降低,并且随吸附过程氯离子降低幅度不同,脱臭油中3-MCPD酯与GEs生成量不同:当脱色油中氯离子含量降幅较小时,经脱臭过程GEs生成量明显低于3-MCPD酯;当脱色油中氯离子含量降幅很大时,经脱臭过程3-MCPD酯的生成量低于GEs。以同时降低脱臭过程3-MCPD酯和GEs的生成量为目标,H-2活性炭作为吸附剂是最好的。     

Antioxidative effect of added tea catechins on susceptibility of cooked red meat,poultry and fish patties to lipid oxidation

The comparative antioxidant activity of added tea catechins on susceptibility of cooked and overwrapped red meat (beef and pork), poultry (chicken, duck and ostrich) and fish (whiting and mackerel) to lipid oxidation was investigated. Fresh meats, poultry and fish, purchased from a local market, were trimmed to remove bones, skin and visible fat and minced through a 4-mm plate. The minced muscle from each species was treated with either 1% NaCl (S), 300 mg tea catechins kg⁻¹ minced muscle (TC) or 1% NaCl plus 300 mg tea catechins kg⁻¹ minced muscle (TCS). Control minced muscle samples (C) contained neither NaCl nor tea catechins. Patties (50 g), prepared from treated and untreated minced muscle, were cooked until the core temperature reached 75°C, cooled down to room temperature and held in a refrigerated (4°C) and illuminated (616 lux) display cabinet for 10 days. Oxidative stability (TBARS) was measured at 3-day intervals. The susceptibility of cooked patties to lipid oxidation was closely related to lipid content, concentration of unsaturated fatty acids and presence of iron in different species. Addition of NaCl to raw minced muscle significantly (P<0.05) promoted lipid oxidation for cooked patties regardless of species sources. Tea catechins added at a level of 300 mg kg⁻¹ minced muscle significantly (P<0.01) inhibited the pro-oxidation caused by NaCl and controlled lipid oxidation for all cooked muscle patties examined. Tea catechins at concentrations greater than 300 mg kg⁻¹ were necessary to reduce oxidation for mackerel patties containing high levels of lipids and unsaturated fatty acids. The high affinity of tea catechins for the lipid bilayers of muscle and the radical scavenging abilities of tea catechins may be possible mechanisms to explain the oxidative stability in cooked muscle foods.     

Comparative efficacy of pomegranate juice, pomegranate rind powder extract and BHT as antioxidants in cooked chicken patties

A study was carried out to evaluate the antioxidant potential of pomegranate juice (PJ), rind powder extract (RP) and butylated hydroxyl toluene (BHT) in cooked chicken patties during refrigerated storage. Freshly minced chicken meats were assigned to one of the following four treatments: control (meat treated with no antioxidants); 10 mg equivalent PJ phenolics per 100 g meat; 10 mg equivalent RP phenolics per 100 g meat; 10 mg BHT per 100 g meat. The patties formed from the minced meats were grilled for 20 min and stored under aerobically at 4 °C for 15 days. Total phenolic content (as tannic acid equivalent) significantly (P < 0.05) increased from 152 in control to 195 and 224 μg/g in PJ and RP patties. Addition of PJ or RP did not affect any of the sensory attributes. The TBARS values were significantly (P < 0.05) reduced from 1.272 in control patties to 0.896, 0.763 and 0.203 mg malonaldehyde per kg samples in BHT, PJ and RP patties, respectively. The RP treatment substantially inhibited (P < 0.01) lipid oxidation in cooked chicken patties to a much greater extent than BHT treatment. The PJ or RP at a level of 10 mg equivalent phenolics/100 g meat would be sufficient to protect chicken patties against oxidative rancidity for periods longer than the most commonly used synthetic antioxidant like BHT.     

Comparison of sensory properties of hamburgers cooked by conventional and carcinogen reducing `safe grill' equipment

Hamburger patties (80 g) were cooked on a commercially available control charcoal grill (Sunbeam Model 20701) and ‘Safe Grill' (US Patent 5331, 886 dated 26 July 1994) to center temperatures of 72 and 82°C at low, medium and high fuel levels. Twelve trained panelists evaluated 19 flavor and texture attributes of the grilled patties. The trained panel found significant differences (p  0.05) between the grill treatments for the following attributes: beefy/meaty flavor, char/grilled flavor, tenderness, moistness, oily mouth coating, chewiness and residual particles. Patties cooked on the ‘Safe Grill' were higher in moistness and oily mouth coating. Patties cooked using the patented ‘Safe Grill' method for reducing carcinogens in grilled meat products were more (p  0.10) acceptable to consumers than patties cooked with the same fuel level on the control grill.     

Cholesterol and Lipid Oxidation Products in Cooked Meat as Affected by Raw-Meat Packaging and Irradiation and by Cooked-Meat Packaging and Storage Time

Aerobic packaging significantly increased cholesterol oxidation products (COPs) and thiobarbituric acid reactive substances (TBARS) in cooked turkey, pork, and beef patties after 7‐d storage, but vacuum packaging was very effective in preventing cholesterol and lipid oxidation. Packaging of meat after cooking had a much stronger effect on COPs formation than before cooking, and irradiation had only a minor effect. The amount of total COPs correlated well with TBARS in cooked meat. Turkey had the highest rates of COPs and TBARS formation and beef had the lowest rates after 7‐d storage, which were closely related to the fatty acid composition of meats. 7a‐hydroxycholesterol, 7p‐hydroxycholesterol, and 7‐ketocholesterol were the major COPs detected in all 3 cooked meat patties.     

Tetrahydro-beta-carboline-3-carboxylic acid compounds in fish and meat: possible precursors of co-mutagenic beta-carbolines norharman and harman in cooked foods

The presence of tetrahydro-beta-carbolines and beta-carbolines was studied in raw, cooked and smoked fish and meat. 1,2,3,4-Tetrahydro-beta-carboline-3-carboxylic acid (THCA) usually was the major beta-carboline found, whereas 1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (MTCA) appeared in smoked and 'well done' cooked samples. THCA was detected in raw fish (nd-2.52 micrograms/g), cooked fish (nd-6.43 micrograms/g), cooked meats (nd-0.036 microgram/g), smoked fish (0.19-0.67 microgram/g) and smoked meats (0.02-1.1 micrograms/g). Smoked and cooked samples contained higher amounts of THCA and MTCA than raw products. Deep cooking of fish and meat increased both THCA and MTCA, and this was accompanied by the formation of more beta-carbolines, norharman and harman. The tetrahydro-beta-carbolines THCA and MTCA were chemical precursors of the co-mutagens norharman and harman during cooking. These and previous results confirm that foods are an important source of beta-carbolines in humans.     

油脂脱臭过程氯离子含量对3-氯丙醇酯和缩水甘油酯的影响

对油脂脱臭用直接蒸汽水源中氯离子含量和待脱臭油脂中氯离子含量进行检测分析,并采用不同氯离子含量的直接蒸汽对油脂进行蒸馏脱臭,检测脱臭前后油脂中3-氯丙醇酯（3-monochloro-1,2-propanediol ester,3-MCPD酯）和缩水甘油酯（glycidyl esters,GEs）含量及氯离子含量,研究油脂脱臭过程氯离子含量对脱臭油脂中3-MCPD酯和GEs的影响。结果表明：油脂脱臭用直接蒸汽中氯离子含量随其水源中氯离子含量增加而升高,水源中氯离子含量在对应饱和蒸汽中的保留率约为0.1%;当油脂脱臭用直接蒸汽水源中氯离子质量浓度达到50～200?mg/L时,脱臭油脂中3-MCPD酯含量大幅升高至低质量浓度氯离子水源（1～10?mg/L）脱臭油脂中含量的2.6?倍,但脱臭油脂中氯离子含量并未升高;待脱臭油脂中氯离子含量升高会导致脱臭后油脂中3-MCPD酯和GEs含量的升高。在待脱臭油脂中添加质量浓度为100?mg/L的氯化钠溶液0.5～5?mL时（相当于油脂中添加量1～10?mg/kg）,脱臭后油脂中3-MCPD酯和GEs生成量分别为4.49～7.84?mg/kg和14.88～19.84?mg/kg,是待脱臭油脂含量的5.5～9.5?倍和5.8～7.7?倍。因此,控制和减少油脂脱臭过程氯离子含量对降低脱臭油脂中3-MCPD酯和GEs含量有重要作用。     

Addition of tea catechins and vitamin C on sensory evaluation, colour and lipid stability during chilled storage in cooked or raw beef and chicken patties

The effects of addition of tea catechins (TC) and vitamin C (VC) on sensory evaluation, colour and lipid stability in cooked or raw beef and chicken meat patties during refrigerated storage were studied. Fresh beef striploin and chicken breast muscles were minced, following removal of external fat and connective tissue. Following mincing, beef and chicken were assigned to one of the following five treatments: control (meat treated with no antioxidant); TC200, meat plus 200 mg TC/kg muscle; TC400, meat plus 400 mg TC/kg muscle; VC200, meat plus 200 mg VC/kg muscle, VC400, meat plus 400 mg VC/kg muscle. Sodium chloride (1%) was added to all samples. Patties (125 g portions), formed from the above-treated minced meat, were oven cooked, cooled, and packaged in 30% CO₂:70% N₂. Fresh raw beef and chicken patties were packaged in 80% O₂:20% CO₂. All samples were stored for up to 7 days under fluorescent lighting at 4 °C. Sensory parameters (colour, flavour, taste, tenderness and overall acceptability) were evaluated on cooked beef and chicken patties after 1, 3 and 6 days of storage. Surface colour (Hunter L, a and b values), and lipid oxidation (2-thiobarbituric acid reactive substances) were measured on days 1, 3 and 6 of storage for cooked meats and on days 2 and 7 for raw beef and chicken. Tea catechins addition (200 or 400 mg/kg) to minced meat caused (P < 0.05) discolouration in cooked beef and chicken meat patties and significantly reduced (P < 0.001) lipid oxidation in cooked or raw beef patties compared to the control. Beef, either raw or cooked, was more susceptible (P < 0.01) to oxidation compared to chicken. Raw meat stored in high oxygen conditions was more susceptible to lipid oxidation than cooked meat stored in anaerobic conditions. Tea catechins treatments (TC200 and TC400) inhibited (P < 0.05) lipid oxidation in raw beef to a greater extent than vitamin C treatments (VC200 and VC400). These results indicate that tea catechins are potent natural antioxidants and exhibit greater antioxidant efficacy compared to vitamin C.     

食用油与氯化钠模型反应中氯丙醇酯的消长规律

为研究热加工过程中食用油与NaCl反应产生3-氯-1,2-丙二醇酯(3-monochloropropane-1,2-diol ester,3-MCPD酯)和2-氯-1,3-丙二醇酯(2-monochloropropane-1,3-diol ester,2-MCPD酯)的变化规律,分别建立食品和煎炸油2个体系模型,考察食用油种类、NaCl含量、反应温度、反应时间、含水量和pH值等因素对2-MCPD酯和3-MCPD酯的含量影响。结果表明:2种模型反应中,食用油种类、反应时间、反应温度和NaCl含量对2-MCPD酯和3-MCPD酯的含量变化有着较大的影响;通过比较发现,在食品模型中,2-MCPD酯和3-MCPD酯的含量随反应温度的增加(100~190℃)呈现下降趋势,分别下降5%和20%,然而在煎炸油模型中,随反应温度的增加(100~220℃)两者呈现增加趋势,分别增加7倍和8倍。另外,随NaCl含量和反应时间的增加,2个模型反应中的2-MCPD酯和3-MCPD酯的含量变化趋势不完全一致。这说明2-MCPD酯与3-MCPD酯虽然结构近似,但消长规律不同。该研究结果可为有效减少热加工食品中氯丙醇酯的含量提供参考。     

Inhibition of Lipid Oxidation in Chicken by Carnosine and Dietary α-Tocopherol Supplementation and its Determination by Derivative Spectrophotometry

The antioxidant activity of carnosine in chicken meat, and its relationship to dietary α-tocopherol supplementation, was examined. Broiler chickens were fed diets containing 30 (basal) or 200 (supplemental) mg α-tocopherol acetate kg⁻¹ feed for 6 weeks. Raw and cooked thigh meat patties containing carnosine (0–1·5%) were prepared. Lipid oxidation, during refrigerated storage under fluorescent light, was assessed by monitoring malonaldehyde formation, using the TBA assay and single wavelength (conventional) or first derivative spectrophotometry. In raw patties, added carnosine improved oxidative stability for up to 10 days of refrigerated storage. In cooked patties, the 1·5% carnosine level provided the best antioxidant protection during 7 days of storage. Carnosine (1·5%) was at least as effective as supplemental α-tocopherol in improving the oxidative stability of raw and cooked patties. The presence of both antioxidants had an additive effect on oxidative stability. Overall, the use of derivative spectrophotometry improved the specificity of the TBA assay for monitoring MDA formation in refrigerated meats.     

油脂微波加热模型中3-氯-1,2-丙二醇脂肪酸酯的形成

通过建立油脂微波加热模型,研究不同的油脂微波加热后3-氯-1,2-丙二醇（3-chloropropane-1,2-diol,3-MCPD）脂肪酸酯含量的变化情况以及NaCl溶液、pH值、时间、不连续微波和金属离子等因素对3-MCPD脂肪酸酯形成的影响。结果表明：1）熟榨植物油微波加热后3-MCPD脂肪酸酯含量增加均超过9 mg/kg,远超过其他植物油。2）3-MCPD脂肪酸酯含量随NaCl的质量浓度增加而增加,随NaCl溶液体积分数的增加呈先增加后减少趋势。3）酸性环境促进3-MCPD脂肪酸酯形成。4）微波加热10 min内,3-MCPD脂肪酸酯含量与时间呈正相关。5）微波总时间一定的情况下,不连续微波产生的3-MCPD脂肪酸酯明显少于连续微波。6）金属离子作为催化剂参与活性中间物的形成,能明显地促进3-MCPD脂肪酸酯的形成。上述结果可为食品微波加工处理过程中危害物3-MCPD脂肪酸酯的控制研究提供数据支持。     

Comparative mutagenicity studies on fried minced beef,grilled sausage and grilled hamburgers

The mutagenicity of the basic fractions of fried beef patties, grilled hamburgers and grilled sausages was determined in the Ames test using activation systems (S9-mix) derived from untreated and Aroclor-pretreated rats and hamsters, and from rats pretreated with 3-methylcholanthrene or phenobarbitone. In order to indicate whether the mutagenic activity was due to the presence of thermally generated amino imidazo aza-arenes of the type previously identified in heated meat products (i.e. 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,4-dimethylimidazo-[4,5-f]quinoline (MeIQ) and 2-amino-3,8-dimethylimidazo[4,5-f]quin-oxaline), these compounds were assayed under the same conditions. The mutagenicity of the basic fractions of the cooked foods and of the three aza-arenes varied with the activation system used. The activation patterns of the basic fractions from fried beef and grilled sausages resembled that of IQ, whereas that of grilled hamburgers was more similar to that of MeIQ. Interestingly the total mutagenic activity of fried beef patties was greater than that of grilled hamburgers.     

The effect of cooking methods on mineral and vitamin contents of African catfish

Proximate composition, mineral and vitamin contents (A, E, B₁, B₂, niacin and B₆) were investigated in cooked African catfish. Different cooking treatments were used (baking, grilling, microwaving and frying). The protein and ash contents increased in all cooked fish. The fat content increased only in fried fillets. The moisture content of cooked fish decreased. Mineral levels were affected by cooking methods, except for Cu Although the vitamin A content significantly increased in grilled and fried fish, vitamin E increased in all cooked fish. Vitamin B₁ content of cooked fish significantly decreased. Vitamin B₂ and niacin contents of grilled fish increased significantly. B₆ content of cooked fish significantly decreased but this did not occur for the grilled fish. High levels of vitamin and mineral contents were found in grilled catfish.     

Conjugated Linoleic Acid Reduces Lipid Oxidation in Aerobically Stored, Cooked Ground Beef Patties

ABSTRACT: The effect of direct addition of conjugated linoleic acid (CLA) on lipid oxidation was studied. CLA and/or fat trim (4% by weight) were added to the lean trim (96%). Thiobarbituric acid reactive substances (TBARS) were determined on days 0, 3, and 7 for cooked or raw patties stored aerobically at 4 °C. Addition of CLA during the grinding process increased CLA isomers in both raw and cooked ground beef and decreased TBARS production ( P < 0.01). CLA caused a greater reduction in TBARS over storage time in cooked patties than in raw patties ( P= 0.006). The concentrations of 18:2n–6 and CLA isomers decreased with storage time. CLA increased 18:2n-6, whereas most fatty acids were decreased by the addition of CLA. CLA did not affect percentages of fat and moisture, cooking loss, or meat color (L*, a *, b *) ( P > 0.60).     

Comparison of aroma characteristics of 16 fish species by sensory evaluation and gas chromatographic analysis

The aroma properties of fish broths prepared from 16 fish species (10 saltwater, three freshwater, two anadromous and one brackish water species) were described quantitatively by reference to 10 sensory attributes. Principal component analysis (PCA) and cluster analysis of sensory attributes classified the fish into four groups. Group 1, characterised by a strong ‘green’ odour, comprised all three freshwater species (loach, pond smelt and carp), two saltwater whitefish species (snapper and conger) and eel. Group 2 included migratory coastal species (sardine, banded blue‐sprat and mackerel) and was distinguished by strong ‘fish oil’ and ‘grilled fish’ notes. Group 3 consisted of swordfish, sablefish and salmon, which exhibited a strong ‘fried chicken’ note. Group 4 included flounder, cod, tuna and goby, which were scored high for ‘cooked fish’, ‘roasted soy sauce’, ‘canned tuna’ and ‘sweet’ aromas. Partial least squares regression (PLSR) models derived from selected influential peaks in the gas chromatograms of the volatile components in the broths for each attribute were highly predictive (R² ≥ 0.936). The selected peaks corresponded well to each sensory attribute. © 2003 Society of Chemical Industry     

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.     

植物油精炼过程中缩水甘油酯和3-氯丙醇酯的形成及脱除研究进展

缩水甘油酯(GEs)和3-氯丙醇酯(3-MCPDE)是植物油精炼过程中产生的主要污染物之一。GEs和3-MCPDE伴随食用油摄入人体后,经脂肪酶水解产生的缩水甘油和3-氯丙醇具有肾脏毒性和遗传毒性。植物油中GEs和3-MCPDE主要产生于油脂精炼脱臭工段,脱臭温度、脱臭时间对GEs和3-MCPDE的生成影响巨大。从油脂精炼加工过程中GEs和3-MCPDE的形成及脱除等方面进行了综述,指出脱色和脱臭工段可促进GEs和3-MCPDE的生成,当前可通过抑制及脱除其前体物质、优化植物油脱臭条件、脱除精炼油中的GEs及3-MCPDE等方式降低植物油中GEs和3-MCPDE含量。酶制剂具有安全、无污染等优点,通过酶法酯交换降低待脱臭油脂中的甘油二酯和甘油单酯,进而减少脱臭过程中GEs及3-MCPDE的生成是降低GEs和3-MCPDE的发展趋势。     

Evaluation of salt, polyphosphates and their blends at different levels on physicochemical properties of buffalo meat and patties

The effects of sodium pyrophosphate (SPP), sodium tripolyphosphate (STPP), sodium hexametaphosphate (SHMP), sodium acid pyrophosphate (SAPP) and their blends at different levels (0·3, 0·5 and 0·7%), along with 2% sodium chloride on certain quality parameters of buffalo meat and patties were evaluated. The SPP, STPP and phosphate blends significantly increased pH, water-holding capacity (WHC), emulsifying capacity (EC), extractability of salt soluble proteins (SSP), colour of ground meat, decreased cooking loss (CL), improved emulsion stability (ES) and enhanced yield, texture and moisture retention of cooked patties. Compared to these phosphates, SAPP and SHMP had significantly poorer effects on improving the quality of meat and patties. The order of effectiveness of phosphates was SPP > STPP > SHMP. In general, pH, WHC, SSP, ES, yield and moisture content of patties increased progressively with increasing level of phosphate while CL decreased. Among blends containing two polyphosphates, those of 90% SPP + 10% SHMP and 75% SPP + 25% STPP were relatively more effective. A phosphate blend consisting of 65% SPP, 17·5% STPP and 17·5% SAPP was equally effective as that of SPP in improving the functionality of hot and chilled meat and had the advantage of reducing the amount of sodium by 3%.