Combined effect of gamma-irradiation and conventional cooking onAeromonas hydrophila in meatball

Irradiation combined with a conventional cooking procedure was applied to meatball and the effects on bacterial load and inoculatedAeromonas hydrophila were determined. Meatball samples were irradiated by using a⁶⁰Co source at the dose levels of 0, 0.30,0.75,1.50,2.50 kGy and cold stored at 4±1°C for 7 days. Bacterial load and the count ofA. hydrophila decreased when the irradiation dose level increased. A minimum inhibition effect was found at the dose of 0.30 kGy. Irradiation in combination with a conventional cooking procedure was found to be more effective in reducingA. hydrophila and the bacterial load in meatball. This study indicated that a dose of 0.75 kGy was sufficient to destroy approximately 10⁴ cfu/g ofA. hydrophila in meatball.     

Effect of cooking procedures on tylosin residues in chicken meatball

Most information about drug residues is related to their concentrations in raw products. The objective of this study was to assess the effects of various microwave and boiling treatments on the stability of different concentrations of tylosin in chicken meatballs. The chicken meatball samples (75 g) were prepared and fortified by 3 concentrations of tylosin (100, 200 and 300 μg kg^?1) and were cooked by boiling (100 °C for 10, 20, 30 min) and microwave procedure (power 450 W for 1, 1.5 and 2 min). The tylosin content was measured in raw and cooked samples through the use of high performance liquid chromatography. The microwave and the boiling process significantly reduced the tylosin. In both procedures, there were negative correlations between the length of cooking time and the reduction percentage of tylosin. In addition, tylosin reduction percentage in chicken meatball cooked by boiling depended on its concentration in uncooked samples. There was a relationship between tylosin reduction percentage and the increase in the internal temperature and weight loss during the cooking process. The results of this study indicate that tylosin residues in the food are decreased during the cooking process. Thus, given that a food product is cooked to be consumed, the surveillance of data obtained from tylosin measurement in the raw tissues samples could not be considered as consumers’ exposure to tylosin via dietary intake.     

冲激技术在常规间歇蒸煮中的应用

通过介绍冲激技术在某浆厂间歇蒸煮中的应用,说明冲激程序操作是一种有效的立锅蒸煮的辅助技术,合理使用,可提高蒸煮质量和稳定生产,减少故障。     

The effect of microwave and conventional cooking on the temperature profiles and microbial flora of minced beef.

Beef mince samples were cooked to the rare, medium and well done states by microwave and conventional oven methods. The raw samples all contained large numbers of contaminating organisms and low numbers of Listeria monocytogenes were detected in the majority of samples. A substantial proportion of the contaminating flora survived in mince cooked by microwaves to the rare, medium and well done states, prior to a 30-min standing period. Listeria monocytogenes survived in all samples cooked by microwaves to the rare state, prior to the standing period and was still present in one of three after the standing period. It was also detected in one of three samples cooked to medium prior to a standing period. This organism was not detected in mince cooked by conventional oven methods. In all the samples cooked by microwaves with a standing period and samples cooked to rare and medium by conventional oven, survival of some of the microflora occurred. The survival rate decreased with the severity of the cooking treatment.     

香味调料在烹饪中的作用

烹饪加工中常需加香味调料,用以改善或增加菜点的香气,或掩盖原料中的不良气味。烹饪中使用的都是植物性天然香味调料。不同的香味调料使用的民有所不同,所用形态也有所差异。使用香味调料时应根据不同的 同的质量要求和工艺过程来选择,以求获得最佳的风味效果。     

蒸煮助剂对稻麦草亚硫酸钾蒸煮的作用

研究了新型蒸煮助剂磷酸钾和常规蒸煮助剂蒽醌、CT-1在稻麦草的亚硫酸钾蒸煮中的作用.实验结果表明磷酸钾对稻草和麦草亚硫酸钾蒸煮具有不同程度降低纸浆硬度的作用.蒽醌对于麦草亚硫酸钾法蒸煮有显著作用.而蒽醌和CT-1对于稻草亚硫酸钾法蒸煮没有起到明显作用.     

魔芋胶在低脂猪肉丸中的应用研究

魔芋胶是一种优质的膳食纤维和功能性食品胶,为降低猪肉丸中的脂肪含量,改善其食用品质,本实验采用单因素分析法及正交实验设计,用质构仪测定猪肉丸的四个重要质构指标:硬度、弹性、黏聚性和耐咀性,并以此为基础确定综合质构指标,向猪肉丸中添加魔芋胶,研究其对肉丸品质的影响。结果表明,添加质量分数为2%的魔芋胶,不会影响肉丸的质构品质,并且可以降低脂肪含量。最终确定猪肉丸中优化的添加物量为:魔芋胶2g/100g猪肉,淀粉16g/100g猪肉,碱[Ca(OH)2]0.48g/100g猪肉。      

Tenderness and collagen composition of beef semitendinosus roasts cooked by conventional convective cooking and modeled, multi-stage, convective cooking

Beef semitendinosus roasts were cooked in a forced-air convection oven using conventional or modeled, multi-stage cooking. Conventional cooking was defined as cooking at 163°C to a core endpoint of 65°C. The model method was developed using a finite difference heat and mass transfer model optimized for a three-stage cooking process that included preheating, holding, and finishing. Model cooking resulted in lower (P<0.05) Warner–Bratlzer peak shear force values than conventional cooking (3.3 vs 4.7 kg). Collagen total unaltered fraction was lower (44 vs 55%, P=0.05) and enzyme labile fraction was higher (56 vs 45%, P<0.05) in the model-cooked samples than in conventionally cooked samples. The three-stage cooking process results in a more tender product without adversely affecting product yield.     

Comparison of the effects of microwave cooking and conventional cooking methods on the composition of fatty acids and fat quality indicators in herring

The aim of this study was to examine the changes which occur under the influence of different heating methods in the compositions of fatty acids and selected fat quality indicators in fillets of herring. The results that are compared herein were obtained via conventional culinary techniques and using microwave radiation. Culinary processes like boiling, grilling and frying, whether done conventionally or with a microwave oven, did not lead to a reduction in the n-3 polyunsaturated fatty acids (PUFAs) fraction of the total fatty acids, indicating that these fatty acids have a high durability and a low susceptibility to thermal oxidative processes. The culinary processes used in this study also had an insignificant influence on the fat quality indicators--the peroxide and anisidine value. The fat quality indicators in herring, both after conventional and microwave heating, differ little, and indicate a low content of primary and secondary products of oxidation.     

Phenolic compounds in tomatoes. Natural variations and effect of gamma-irradiation

A method for determination of p-hydroxybenzaldehyde, p-coumaric acid, ferulic acid, rutin and naringenin in tomatoes based on HPLC with coulometric electrode array detection was developed. After lyophilisation and extraction the compounds were separated isocratically (acetonitrile/buffer: 14:86, v:v, or acetonitrile/buffer: 27:73, v:v, flow rate: 0.8 ml/min) on reversed phase columns (LiChrospher 60 RP select B or Spherisorb ODS2) and detected at 16 respectively 10 working electrodes set at potentials between +50 and +750 mV against palladium reference electrodes. The natural content of these components showed a strong variation between different varieties, harvests and degrees of maturity. Gamma-irradiation reduced the concentration of the phenolic compounds markedly in all tomato samples investigated, however, this change was smaller than the naturally occurring differences. The irradiation products vanillin and eriodictyol, identified in standard solutions, could not be found in irradiated tomatoes.     

The antioxidant capacity and polyphenol content of organic and conventional retail vegetables after domestic cooking

Vegetable consumption is associated with health benefits. Organic foods are thought to have higher contents of antioxidant substances. The objective of this work is to quantify soluble and hydrolyzable polyphenols, ascorbic acid, and the antioxidant capacity of fresh conventional and organic retail vegetables (potato, carrot, onion, broccoli, and white cabbage) while evaluating the effect of boiling, microwaving, and steaming on these parameters. The recovery rate for soluble and hydrolyzable polyphenols was variable according to the vegetable analyzed. However, soluble polyphenols resulted in lower recovery rates than did hydrolyzable phenolics after cooking. Organic vegetables showed higher sensitivity to heat processing than did conventionally grown vegetables. In general, cooking was found to lead to reductions in the antioxidant capacity for most vegetables, with small differences between the cooking methods applied. Even with the alterations in their content, polyphenols showed a positive correlation with antioxidant capacity in raw and cooked vegetables from both types of agriculture.     

胡萝卜豪猪肉丸子的开发研制

为加大对豪猪开发利用力度,满足人们生活需要,特进行胡萝卜豪猪肉丸子试制。实验表明:将豪猪肉用五倍清水漂洗三次,豪猪肉:猪肥膘肉=5∶4,用盐量为3%,淀粉用量20%,胡萝卜用量12%,在10～15℃下擂溃30min,成型后在95～100℃下加热熟化20min即可得到味美、色佳、弹性良好的胡萝卜豪猪肉丸子制品。     

用碱量对烧碱法麦草浆蒸煮的影响

麦草原料制浆的主要方法是烧碱法,烧碱在蒸煮过程中起着脱除木素的作用,粗浆硬度一般随着用碱量的提高而降低。为了深度脱木素,一味地提高用碱量是否会使木素的含量和粗浆硬度一直降低下去？通过研究证明,烧碱的作用是有限的,当用碱量提高到一定程度时,粗浆硬度曲线下降的趋势变得非常平缓,脱木素非常困难,几乎成一直线。     

Combined effect of cooking (grilling and roasting) and chilling storage (with and without air) on lipid and cholesterol oxidation in chicken breast

The oxidation of the lipid fraction and cholesterol in raw and cooked chicken breast samples stored for 0 and 6 days at 4 degrees C under aerobic conditions and in vacuum packaging was studied. The multivariate statistical analysis showed significant effects of both culinary process and storage conditions on the lipid and cholesterol oxidation process, with a significant interaction between the two variables. Aerobic storage increased thiobarbituric acid reactive substances (TBA) from 0.04 to 0.06 ppm for raw samples, from 0.21 to 1.20 ppm for grilled samples, and from 0.24 to 1.62 ppm for roasted samples. During vacuum storage, only roasted samples showed significant increases in TBA. Levels of total cholesterol oxidation products (COP) remained low (2.88 to 4.35 microg/g of lipid) for all raw samples. Cooking increased COP levels to 12.85 and 11.54 microg/ g of lipid for grilled and roasted samples, respectively. Total COP and all individual COP except for cholestanetriol were significantly correlated with TBA and the peroxide index. However, the most extensive effect was attributable to the aerobic storage of cooked samples, which led to COP levels of 92.35 and 88.60 microg/g of lipid in grilled and roasted samples, respectively. Vacuum packaging did not increase COP levels for cooked samples.     

The effect of cooking on Brassica vegetables

Assessing antioxidant intake requires a food antioxidant database. However, cooking may affect antioxidant content due to antioxidant release, destruction or creation of redox-active metabolites. Here, effects of boiling, steaming and microwaving of broccoli, cauliflower, cabbage and choy-sum (Chinese cabbage) were explored by measuring antioxidant contents of raw and cooked vegetables. Cooking water was also tested. For all cooked vegetables, antioxidant content was highest in steamed > boiled > microwaved, and decreased with longer cooking time, regardless of method. All steamed vegetables had higher antioxidant contents than had matching raw vegetables. Effects were variable for boiling and microwaving. Microwaving caused greater antioxidant loss into cooking water than did boiling. Marked losses of anitoxidants occurred in microwaved cabbage and spinach. To assess food antioxidant content/intake accurately, cooking effects need detailed study. Steaming may be the cooking method of choice to release/conserve antioxidants. The cooking water is a potentially rich source of dietary antioxidants.     

家用微波炉烹制米饭对生成致癌物质丙烯酰胺的影响

建立萃取/离心分离/吸附/GC检测谷类食品中致癌物质丙烯酰胺(Am)含量的分析方法,Am的GC定量检测限为2×10-2～3×103mg/L。采用(1)常规加热、(2)常规加热 微波复热、(3)微波加热及(4)微波加热 微波复热4种模式考察了家用微波炉烹制米饭对促成Am的影响,模式(1)中Am含量为30μg/kg米饭,而模式(2)、(3)及(4)中Am含量高于模式(1)2～9倍,解释为由微波的加热特性及微波的非热效应所致。与小于1mg/kg食品的德国标准相比,该结果仍属于安全范围,但微波炉烹制米饭增加Am含量的现象应引起重视。     

The effect of cooking on the glucosinolates content in white cabbage

The effect of different cooking times on the GLS content in white cabbage (Brassica oleracea L. var. capitata f. alba) was determined. Cooking of cabbage for 5-30 min caused a gradual decrease in the GLS content. The most efficient reduction of the GLS content (by about 35%) occurred during the first minutes of cooking. As the cooking time was extended by another 5 min, each time the GLS content decreased by 10-15%. Higher losses in indole GLS, as compared to those of aliphatic ones, resulted from more efficient diffusion of those compounds to cooking water. The GLS content in cooking water, irrespective of the cooking time of white cabbage, remained rather stable, whereas the content of indole GLS was between 3.5- and 4-fold higher in comparison to that of aliphatic GLS. Taking into consideration the rate of changes in the content of particular GLS in cabbage and the GLS content in cooking water, it can be stated that glucoiberin was more thermolabile than other GLS.     

The effect of ripening and cooking temperatures on proteolysis and lipolysis in Manchego cheese

The influence of ripening temperature on proteolysis and lipolysis was studied on four lots of raw ewe's milk Manchego cheese held for 60 days at 5, 10, 15 or 20°C. Mean levels of pH 4·6, trichloroacetic acid and phosphotungstic acid soluble N in 20°C cheeses were 52%, 78% and 95% higher than the respective levels in 5°C cheeses at the end of the ripening period. Free fatty acids content after 60 days was 90% higher in 20°C cheeses than in 5°C cheeses. Significant effects of the cooking temperature of the curd (30, 36, 38 or 40°C) on pH, moisture and NaCl content were recorded, but levels of nitrogenous fractions or free fatty acids in 60-day cheeses were not affected.