Effect of different cooking methods on the oxidation,proximate and fatty acid composition of silver catfish (Rhamdia quelen) fillets

The influence of seven cooking methods (boiling, conventional baking, microwave baking, grilling, deep-frying in soybean oil, canola oil, or partially hydrogenated vegetable oil) on the oxidation, proximate and fatty acid composition of silver catfish (Rhamdia quelen) fillets was evaluated. All the treatments reduced moisture and increased the protein content. The free fatty acid content of the fillets was significantly reduced by the different cooking methods, while conjugated diene levels and peroxide values decreased for all fried samples, but remained constant in the samples subjected to the other cooking methods. Boiling and baking increased thiobarbituric acid reactive substances (TBARS), while grilling and frying did not change TBARS. Boiling, baking, and grilling did not affect the silver catfish fillets fatty acid composition. Frying in canola oil increased n−3/n−6 ratio, while frying in soybean oil increased the general polyunsaturated fatty acid content, and frying in hydrogenated vegetable oil incorporated trans fatty acids in the fillets.     

EFFECTS OF TRIMMING AND COOKING BY SEVERAL METHODS ON POLYCHLORINATED BIPHENYLS (PCB) RESIDUES IN BLUEFISH

Bluefish were captured in the Atlantic Ocean near Long Island to study the effects of trimming and cooking on reduction of residues of polychlorinated biphenyls (PCBs). The mean concentration (standard error) of PCBs in the raw untrimmed fillets of the fish captured was 1.76 ± 0.17 ppm on a dry weight basis with range of 0.58 to 7.47. A direct relation between the concentration of PCBs in the raw fish fillets and their fresh weight showed a correlation coefficient of only 0.39. About twice the concentration of PCBs were found in the skins as compared to the dorsal and ventral sections of the raw fillets. Trimming the fillets resulted in a reduction in PCB residues averaging 59.4% with a further average reduction of 7.4% from baking, broiling, frying or poaching. There were no significant (p > 0.05) differences among the combined trimming and various cooking methods in the magnitude of reduction of PCB residues. The total quantities of PCBs found in the oil collected after baking, broiling or frying the fillets were less than could be accounted for as total cooking losses thus indicating that vaporization of PCBs during cooking may also occur.     

Chlordane and toxaphene residues following cooking of treated channel catfish fillets

The reduction in residues of chlordane and toxaphene following cooking (frying, baking, and smoking) of fillets obtained from treated Channel catfish (Ictalurus punctatus) was determined. On average, cooking reduced moisture content by 17% and increased fat content by 28 to 274%. Frying reduced chlordane residues by 56 to 86% on a dry basis (db) or 84 to 92% on a percent fat basis (fb) when raw fillets were compared to cooked fillets. Baking and smoking reduced chlordane significantly less (P < 0.05) than frying with reductions in residues of 12% and 9% (db) or 30% and 33% (fb), respectively. Frying reduced toxaphene residues by 40 to 49% (db) or 65 to 77% (fb), while baking and smoking reduced toxaphene by 35% and 24% (db) or 51% and 59% (fb), respectively.     

添加不同成分的外裹糊鱼块深度油炸过程中的传质动力学

将大豆纤维、黄原胶和乳清蛋白分别添加到基本外裹糊（中筋小麦粉、玉米淀粉、泡打粉、食盐）中制成 外裹糊鱼块,在170 ℃大豆油中油炸30、60、90、120、150 s和180 s,测定油炸外裹糊鱼块的水分及油脂、表面油 脂和表面渗透油脂质量分数,采用菲克第二定律和一级动力学方程分析油炸过程中的传质动力学,通过苏丹红染 色实验模拟油脂吸收。结果显示：大豆纤维组、黄原胶组和乳清蛋白组外壳水分质量分数均随油炸时间的延长而降 低,而鱼块水分质量分数先降低后升高再降低;油炸0～120 s时,大豆纤维组、黄原胶组和乳清蛋白组外壳油脂质 量分数均升高,油炸120～180 s时降低。菲克第二定律拟合大豆纤维组、黄原胶组和乳清蛋白组水分扩散系数分别 为0.003 8、0.003 3 s－1和0.003 9 s－1;一级动力学方程拟合大豆纤维组、黄原胶组和乳清蛋白组油脂吸收的传质系数 分别为0.062、0.059 s－1和0.061 s－1。油炸30～60 s,3 组外裹糊鱼块的油脂渗透幅度差异不显著;油炸90～180 s, 乳清蛋白组油脂渗透最深,黄原胶组最浅。表明外裹糊中分别添加大豆纤维、黄原胶和乳清蛋白影响了外裹糊鱼块 深度油炸过程中的水分蒸发和油脂吸收,导致传质系数差异明显。     

调理草鱼片在不同加热方式下的品质变化

目的 比较不同加热方式下调理草鱼片的品质变化。方法 对比不同加热方式(水浴、汽蒸、油炸和微波)处理后调理草鱼片的感官、水分含量、烹饪损失率、色度值、质构、微观结构和挥发性风味物质的变化。结果 水浴和油炸加热对调理草鱼片的感官评价显著高于其他加热方式(P<0.05);水浴加热和汽蒸加热更有利于提升亮度值;汽蒸加热后的水分含量显著高于其他组别(P<0.05);不同加热方式对调理草鱼片的蒸煮损失率影响显著(P<0.05);水浴和汽蒸加热后的硬度显著低于其他组别(P<0.05);汽蒸加热后的调理草鱼片纤维组织紧致清晰,与对照组更为相近;共检测出86种挥发性风味物质,其中醛类、醇类、酮类和酸类为调理草鱼片的主要挥发性风味物质,汽蒸加热后的主要挥发性风味物质在种类和数量上优于其他加热方式。结论 不同加热方式后的调理鱼片品质差异明显,汽蒸加热更有利于调理草鱼片的加热。     

Proximate Composition, Mineral Content, and Fatty Acids of Catfish (Ictalurus punctatus, Rafinesque) for Different Seasons and Cooking Methods

The effect of conventional cooking methods and the influence of season upon proximate composition, mineral, and fatty acid profile was studied in catfish (Ictalurus punctatus, Rafinesque) fillets. Seasonal (August, December, and April purchased fillets) influences were minimal. As expected, fried catfish fillets had significantly altered (P ≤ 0.05) fatty acid profiles compared to the raw and baked fillets. All three cooking treatments resulted in significant differences (P ≤ 0.05) in proximate composition and in the levels of potassium, phosphorus, magnesium, and iron. The information presented would be useful for nutrient data banks when dietary intake of such items is of interest.     

THE EFFECTS OF SEVERAL METHODS OF FISH PREPARATION ON RESIDUES OF POLYCHLORINATED BIPHENYLS AND SENSORY CHARACTERISTICS IN STRIPED BASS

Fifty striped bass were captured in Long Island Sound. The concentration of polychlorinated biphenyls (PCBs) was determined in the fish fillets before and after baking, boiling, frying, microwaving or poaching to study possible reduction of PCB residues by these cooking procedures. The cooked portions were evaluated for sensory characteristics. PCB content was significantly reduced by cooking, but there were no significant differences in that reduction among the six cooking methods. Tasters preferred fish prepared by "oil-based" cooking methods (bake, broil, fry) as compared to "water-based" methods (microwave, poach, boil).     

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.     

烫漂温度及空气炸时间对鲶鱼鱼皮品质的影响

为了解烫漂温度及空气炸时间对鲶鱼鱼皮品质的影响,本文研究了50、70、90 ℃烫漂后鲶鱼鱼皮的蒸煮损失率和热稳定性,在烫漂的基础上分别炸制2、4、6、8、10、12 min后对其水分、脂肪、脆度、横向弛豫时间（T₂）进行了测定,并对不同烫漂温度及其空气炸12 min的鱼皮微观结构进行了分析。结果表明:70 ℃烫漂的鱼皮蒸煮损失率为2.15%,热稳定性温度分别为121.97、146.88 ℃,在空气炸12 min时水分含量为2.89%,脂肪含量为10.85%,形变距离为0.13 mm;相比较50 ℃和90 ℃,70 ℃烫漂的鱼皮,蒸煮损失率适中,热稳定性较好,在空气炸12 min时,水分含量最低,形变距离最小,脂肪含量较低,结构均匀平整。由此可见,70 ℃烫漂下的空气炸鱼皮整体更利于后期产品的开发。     

添加成分对外裹糊流变性能及外裹糊鱼块油炸过程油脂渗透的影响

将分别添加黄原胶（0.4%）、大豆纤维（2%）、乳清蛋白（4%）的外裹糊制作油炸外裹糊鱼块,通过测定外裹糊的黏性模量（G”）和弹性模量（G’）以及油炸外裹糊鱼块的水分和油脂含量、微观结构、苏丹红染色水平和油脂分布,探讨添加成分对外裹糊流变性能及外裹糊鱼块深度油炸过程油脂渗透的影响。结果显示：4 种外裹糊（包括对照组,即外裹糊中未添加黄原胶、大豆纤维或乳清蛋白）的G”值和G’值随温度升高先减小后增大,最后趋于稳定,黄原胶组外裹糊的G”值和G’值最大。油炸后黄原胶组的外壳结构紧密,鱼块孔隙小且数量少,具有较高的水分含量和较低的油脂含量。苏丹红染色幅度最大的是对照组,油脂已通过外壳渗入鱼块;黄原胶组染色幅度最小,只出现在外壳中。油脂主要分布在外壳孔隙周围,黄原胶组的荧光强度最低,其次是乳清蛋白组和大豆纤维组,对照组的荧光强度最高。研究结果表明外裹糊中分别添加黄原胶、大豆纤维、乳清蛋白明显影响了外裹糊的流变性能,抑制了外裹糊鱼块深度油炸过程的油脂渗透。     

Effect of precooking and polyphosphate treatment on the quality of catfish fillets cooked in pouch in boiling water

Cooking or reheating food in a vacuum‐sealed bag has been a common method of preparing vegetables, meats and poultry products. However, there are very few examples of vacuum‐sealed bags designed for cooking catfish fillets. The objective was to examine properties of raw frozen and precooked frozen catfish fillets that were cooked in a vacuum‐sealed pouch in boiling water. The effect of a commercial polyphosphate blend (IQF) on product properties was also evaluated. Sample analyses included weight loss, proximate content, colour (CIE L*a*b*), pH, mechanical texture and lipid peroxidation (TBARS) measurements. Both raw frozen and precooked frozen IQF fillets showed a significantly lower per cent moisture loss after cooking, of less than 2.7% relative to the fillets without polyphosphate (6.2–7.4%). Colour analysis showed a significantly higher b*(C) (yellowness) value for fillets without polyphosphate. Similar texture properties were observed between cooking treatments, with a harder texture (~1.3–1.7 times) determined for fillets without polyphosphate.     

预熟制对油炸猪肉丸品质的影响

探讨煮制、蒸制和微波3 种预熟制处理的加入对油炸猪肉丸品质的影响。以直接160 ℃油炸6 min的猪肉丸为对照,测定经过煮制、蒸制和微波预熟制加热处理10 min后160 ℃油炸2 min的猪肉丸的品质指标。结果表明：与对照组相比,煮制和微波预熟制显著影响油炸猪肉丸的色泽（P＜0.05）,蒸制处理对肉丸色泽影响不显著（P＞0.05）;不同预熟制处理对油炸猪肉丸的弹性和内聚性没有显著影响（P＞0.05）;微波预熟制后油炸猪肉丸的含水率和脂肪含量均显著下降（P＜0.05）,而煮制后油炸的猪肉丸含水率和脂肪含量均显著上升 （P＜0.05）,蒸制后油炸的猪肉丸含水率和脂肪含量变化不显著（P＞0.05）;经感官评定,煮制后油炸猪肉丸感官评分显著降低（P＜0.05）,蒸制和微波预熟制对油炸肉丸感官评分无显著影响（P＞0.05）。微波预熟制可用于生产低脂肪含量油炸制品。     

THE EFFECT OF EDIBLE FILM ON OIL UPTAKE AND MOISTURE RETENTION OF A DEEP-FAT FRIED POULTRY PRODUCT

The recent trend in reducing the fat content in fried foods is leading to the development of low-fat products using batter and breading formulations from protein and other hydrocolloids. The functionality of many of these edible ingredients on moisture retention and fat barrier properties during deep-fat frying is not clearly understood. The objective of this study is to evaluate the effectiveness of hydroxypropyl methylcellulose edible film coating on chicken balls for moisture retention and fat reduction during deep-fat frying. Two sizes (35 and 47 mm) of uncoated and coated chicken balls were fried in peanut oil at 175C for five different frying periods ranging from 30 to 180s for small and 30 to 300s for large balls. The moisture and fat content from the surface layer and core were determined. In comparison to the control, moisture retention up to 16.4% and fat reduction up to 33.7% were observed.     

半干鲢鱼片油炸工艺研究

以鲢鱼为原料,研究油炸前鱼片含水量对油炸产品、油炸条件对鲢鱼片脱水速率、吸油率、产品质构的影响。结果表明,油炸最适条件为180℃,油炸约4.5min,产品最终水分含量在40%左右。油炸前鱼片含水量控制在65%左右,能有效降低油炸时鱼片的吸油且能得到品质较好的鱼片。     

Retention of Oxytetracycline Residues in Cooked Channel Catfish Fillets

Catfish (mean body weight 0.87 kg) treated with oxytetracycline (OTC) at 150.0 mg/kg body weight for 10 days and slaughtered 18 hr after last feeding had higher OTC residue levels than those receiving OTC at 37.5 or 75.0 mg/kg. Individual differences in feed uptake and metabolism of OTC among catfish might contribute to variability in residue. Baking and smoking at 190°C were more effective in reducing OTC residues than frying. The reduction appeared to be related to the final temperature reached and duration of cooking. Results confirmed that common cooking procedures may not completely degrade OTC in catfish fillets.     

Functionality of batters containing different starch types for deep-fat frying of chicken nuggets

The effect of various starch types (amylomaize, corn, waxymaize, pregelatinized tapioca) on quality attributes (texture, moisture content, oil content, color, coating pick up, cooking yield, volume and porosity) of deep-fat fried chicken nuggets were studied. Chicken samples, 0.04 m in diameter and 0.015 m in thickness, taken from the breast portion, were coated with batters composed of a 3:5 solid to water ratio by immersion. The solid content of batter formulations contained equal amounts of corn and wheat flour, 5.0% starch, 1.0% salt and 0.5% leavening agent. As control, batter without starch addition, was used. Samples were fried at 180°C for 3, 6, 9 and 12 minutes. Crispness and oil content of chicken nuggets increased, whereas moisture content decreased with increasing frying time. Starch addition to the formulations increased crispness of the product significantly at the last stages of frying. The highest porosity and oil content was obtained when corn starch was used. Pregelatinized tapioca starch was found to provide a product with the lowest oil content, the highest moisture content, coating pick up and volume.     

Comparison of the effects of four cooking methods on fatty acid profiles and nutritional composition of red mullet (Mullus barbatus) muscle

This study was performed to examine the effects of different cooking methods (frying, steaming, oven cooking, and microwave cooking) on proximate chemical composition, mineral contents, and fatty acids profiles of red mullet (Mullus barbatus) fillets. The frying process caused a significant increase in fat content (from 13.37±0.04 to 34.44±0.20 g/100 g d.w.) and reduced the proportion of the palmitic acid of 50.73% and saturated fatty acids of 56.9%. While, the proportion of polyunsaturated fatty acids (PUFA) increased from 4.04% of total fatty acids for raw fillet to 49.17% of total fatty acids for fried fillets. The steamed, oven-cooked, and microwave-cooked fillets showed the best proportion of fat content, PUFA, and ω-6/ω-3 ratio as compared with fried red mullet fillets. Na, Mg, and Zn contents of cooked fish fillets significantly decreased.     

EFFECTS OF COOKING CONDITIONS AND POST-PREPARATION PROCEDURES ON THE QUALITY OF BATTERED FISH PORTIONS

The effects of different cooking conditions and postpreparation handling on quality of battered fish portions for fast food services were investigated. As the frying temperature increased from 300 to 400°F (149–204°C), the cooking time of battered fish portions decreased from 276 to 202 s. Crude lipid content in the batter decreased as the temperature of the frying oil increased. Holding times (10, 20 min) affected crude lipid contents of the batter depending on the cooking temperature and were lower than an unheld product. Crude lipid contents in the fish fillets were generally higher after frying by 2–3%. The crude lipid uptake by the batter coating differed significantly for the three frying shortenings (partially hydrogenated soybean, V-S oil; animal fat-vegetable blend, A-V Fat; and vegetable-palm oil blend, V-P oil;) compared in this study. This finding contrasts with previously published results. The amount of crude lipid uptake by the fish varied with shortening type and holding times. No consistent trend was observed to occur. Peroxide values increased after 3 days in the V-S Oil and A-V Fat. Flavor scores on battered fish portions cooked in V-S Oil, V-P Oil, and A-V Fat were not statistically different immediately after cooking and after holding for 10- +20-min on the first day. By the second day, differences were observed among the three shortenings. Both shortening type and postpreparation holding times affected the perceived greasiness.     

Effects of Four Cooking Methods on the Proximate, Mineral and Fatty Acid Composition of Fish Fillets

The effects of baking, broiling, deep frying and cooking in a microwave oven on the proximate, mineral and fatty acid composition of grouper (Epinephelus morio), red snapper (Lutjanus campechanus), Florida pompano (Trachinotus carolinus) and Spanish mackerel (Scomberomorus maculatus) were determined. The lipid content of low fat species was not significantly changed by cooking, but lipid was lost from fatty fillets during cooking. The fatty acid composition of all fillets was not significantly changed by baking, broiling or microwave cooking. Deep fried fillets absorbed the major fatty acids in the cooking medium, and as the fillet lipid content increased the extent of absorption of fatty acids from the cooking medium decreased. Sodium, potassium and magnesium levels were decreased when low fat species were cooked, but these minerals were not lost when raw fillets containing higher lipid levels were cooked. Cooking did not significantly affect the concentration of the microelements, zinc, copper, iron and manganese.     

热加工方式对香菇营养特性和抗氧化活性的影响

为探索科学合理的香菇热处理方式,采用水煮、微波、汽蒸、高温高压、油炸5 种加工方式对香菇进行热处理,通过营养成分含量测定、体外模拟胃肠消化实验以及抗氧化活性分析,研究不同热加工方式对香菇营养特性、生物利用度和抗氧化活性的影响。结果表明,水煮、油炸和微波处理总体显著降低了香菇中多糖、总膳食纤维、蛋白质、总酚含量以及1,1-二苯基-2-三硝基苯肼自由基清除率和还原力（P＜0.05）,而汽蒸和高温高压处理对上述指标总体无显著影响或略有提高。水煮使香菇麦角甾醇的含量升高30.22%,而油炸导致其降低24.00%,微波、汽蒸和高温高压处理对其无显著影响。5 种热加工方式总体都能显著提高香菇中多糖、蛋白质和总酚的生物利用度（P＜0.05）,热加工后的香菇蛋白质含量与其生物利用度呈极显著负相关（P＜0.01）,而多糖和总酚含量与其生物利用度无显著相关性（P＞0.05）。热加工后香菇抗氧化活性与其多糖、总膳食纤维和总酚含量呈显著正相关（P＜0.05或P＜0.01）。总体来看,汽蒸和高温高压处理有利于香菇营养成分和抗氧化活性的保留和提高。本研究为科学合理地加工、烹饪、食用香菇及其他食用菌提供了一定的参考。