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1.
采用中压快速制备型色谱-高效体积排阻色谱技术,探索了煎炸次数对大豆油及薯条表面所吸附油脂中极性化合物总量(total polar compounds,TPC)及其组分的影响。结果表明,煎炸薯条后剩余的大豆油中的TPC总量随着煎炸次数的增加而是逐渐增加,而薯条表面所吸附油脂中的TPC含量也随之逐渐增加;同时,煎炸次数的增加,显著改变了极性组分氧化甘油三酯寡聚物(oxidized triglyceride oligomers,TGO)、氧化甘油三酯二聚物(oxidized triglyceride dimers,TGD)、氧化甘油三酯单体(oxidized triglyceride monomers,ox-TG)在大豆油中的分布,而甘油二酯(diacylglycerols,DG)的含量增加缓慢,游离脂肪酸和甾醇(free fatty acids and sterols,FFAsterols)和其他未知小分子化合物的含量呈现波动性变化。煎炸次数严重影响了大豆油和薯条表面所吸附油脂中的TPC及其组分分布,也在一定程度上影响了薯条的健康价值。  相似文献   

2.
Effects of frying and microwave heating on the decomposition of benzoyl peroxides (BPO) in flour were studied. First, BPO and its main decomposition product, benzoic acid (BA), were extracted from different flour products by ultrasonication in ethanol. Next, three samples of commercial flour, two fried foods, and two microwave foods were analyzed by high performance liquid chromatography (HPLC) and mass spectrum (MS). Results revealed that the BPO content decreased after frying and microwave heating treatments. Furthermore, the existence of biphenyl in fried food was successfully verified by HPLC‐MS. Biphenyl that decomposed from BPO may be one source of toxicity in fried foods. In contrast to fried food, new components made through the special heating module were not found in microwave food.  相似文献   

3.
煎炸油中产生的极性成分对食品微观结构和质构的影响   总被引：5，自引：2，他引：5  
研究了煎炸油中产生的极性成分对食品微观结构和质构的影响。用硅胶柱色谱和高效体积排阻色谱测定了极性成分和聚合物含量变化，油炸食品穿孔力和微观结构的变化分别用质构仪和显微镜进行测定和观察。结果表明随着油炸时间延长，极性成分、聚合物含量呈线性增加且二者间也呈线性关系,油炸食品的微观结构越来越差,食品穿孔力虽没有明显变化，但其剪切系数(Kp)有增加而压缩系数(Ka)有减小的趋势。油脂中的极性成分严重影响了食品的微观结构，也在一定程度上影响了食品的Ka、Kp值，但还不能完全通过Ka、Kp的变化来表示油品质对食品质构的影响。  相似文献   

4.
Emissions of low molecular weight aldehydes (LMWAs) from deep-frying of extra virgin olive oil, olive oil, and canola oil (control) were investigated at two temperatures, 180 and 240 degrees C, for 15 and 7 h, respectively. The oil fumes were collected in Tedlar bags and then analyzed by gas chromatography-mass spectrometry. Seven alkanals (C2-C7 and C9), eight 2-alkenals (C3-C10), and 2,4-heptadienal were found in the fumes of all three cooking oils. The generation rates of these aldehydes were found to be dependent on heating temperature, showing significant increases with increases in temperature. The LMWA emissions from both kinds of olive oils were very similar and were lower than those observed from canola oil under similar conditions. These results suggest that frying in any type of olive oil, independent of its commercial category, will effectively decrease the generation of volatile aldehydes in the exhaust. This fact is important because less expensive refined olive oil is usually used for deep-frying operations, whereas extra virgin olive oil is usually used as salad dressing.  相似文献   

5.
油炸藕片含油量快速预测及微观结构的三维重建   总被引：1，自引：1，他引：0  
以油炸藕片为研究对象,首先利用高光谱图像技术(hyperspectral imaging technology,HSIT)结合联合区间偏最小二乘(synergy interval partial least squares,si PLS)和净分析物法(net analyze signal,NAS)提取油炸藕片的光谱信息,建立快速预测模型,并计算每个像素点的油含量值,将其表面油分布可视化;然后利用激光共聚焦显微镜(confocal laser scanning microscopy,CLSM)观察油在细胞中的分布,并扫描藕片Z轴方向序列图片进行微观结构的三维重建。结果显示,优选4个子区间,依据NAS法挖掘同油相关的NAS信号NAsk,建模后其预测集相关系数和均方根误差分别为0.819和0.682 mg/g,表明HSIT可快速预测油炸藕片含油量并可视化表面油分布。经CLSM扫描并图像三维重建后观察,油主要分布在细胞表面、边缘、细胞间隙以及破碎细胞内,且细胞的形状、大小均发生了很大的变化,可观察其内部油分布。结果表明,该研究可为油分布提供有效手段,并依据微观结构的变化为减少含油量提供科学的理论依据。  相似文献   

6.
To determine the effects of gamma-tocopherol on the stability of fried food, potato chips were fried in triolein with 0, 100, or 400 ppm gamma-tocopherol. Potato chips, sampled at 1, 3, and 6 h of frying time, were aged for 0, 2, and 4 days at 60 degrees C and then evaluated for odor attributes by sensory analysis and for volatile compounds by purge-and-trap gas chromatography-mass spectrometry. Oil sampled after 1, 3, and 6 h of frying time from the fryer was evaluated for total polar compounds and retention of gamma-tocopherol. Oil extracted from the potato chips was also analyzed for residual gamma-tocopherol. gamma-Tocopherol disappeared rapidly, with only slight amounts of the original 100 ppm level detectable after the triolein was used for frying. gamma-Tocopherol significantly inhibited polar compound production in the triolein. Results showed that gamma-tocopherol inhibited the oxidation of the fried food even when only very low levels of retained gamma-tocopherol were present in the frying oil or potato chips. Nonanal formation was inhibited by gamma-tocopherol in aged potato chips. Odor analysis of the aged potato chips showed that samples with 0 ppm gamma-tocopherol had a rancid odor after being aged for 4 days. Potato chips with 400 ppm gamma-tocopherol had no rancid odors; however, as the level of gamma-tocopherol decreased in the triolein and in the potato chips, a weak plastic odor characteristic of oxidized triolein was detected.  相似文献   

7.
The effect of superheated steam treatment on the oxidative stability of lipids in packaged Zousoon (pork bundles) was investigated. The aroma quality of Zousoon samples was evaluated by sensory analysis and chromatographic analysis of volatiles. Results of this study indicated that oxidation of lipids occurred in pan-fried Zousoon after prolonged storage. Significant amounts of highly volatile compounds such as formaldehyde, acetaldehyde, acetone, and hexanal in Zousoon were identified by a modified method of cysteamine derivatization followed by gas chromatography-mass spectrometry (GC-MS) analysis. Superheated steam was found to be effective in suppressing lipid oxidation in canned Zousoon as compared with Zousoon fried by the conventional method in a frying pan. The superheated steam-fried samples had relatively low thiobarbituric acid reactive substance (TBARS) and peroxide (POV) values before and after storage, whereas samples prepared by pan frying had relatively high TBARS and POV values before and after storage. Superheated steam-fried Zousoon had superior lipid stability to that prepared by the conventional pan-frying method.  相似文献   

8.
A recently developed HPTLC/UV-FLD method was compared to the routinely used HPLC/UV-FLD method for the quantification of heterocyclic aromatic amines (HAA) formed at trace levels during the heating process of meat. For formation of these process contaminants under normal cooking conditions, beef patties were fried in a double-contact grill at 230 degrees C for five different frying times and extracted by solid-phase extraction. The HAAs most frequently found, that is, 2-amino-1-methyl-6-phenylimidazo[4,5- b]pyridine (PhIP), 2-amino-3,8-dimethylimidazo[4,5- f]quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5- f]quinoxaline (4,8-DiMeIQx), 9 H-pyrido[3,4- b]indole (norharman), and 1-methyl-9 H-pyrido[3,4- b]indole (harman), were quantified by two chromatographic methods, which were orthogonal to each other (normal versus reversed phase system). Both methods showed a similar performance and good correlation of the results ( R (2) between 0.8875 and 0.9751). The comparison of running costs and run time in routine analysis proved HPTLC/UV-FLD to be more economical (factor of 3) and faster (factor of 4) due to its capability of parallel chromatography. The HAA findings calculated by standard addition increased with the heating time from <1 to 33 microg/kg related to 3-6 min of frying time. The precision (RSD) was between 7 and 49% (HPTLC) and between 5 and 38% (HPLC) at these very low HAA levels formed.  相似文献   

9.
The addition of spinach (Spinacia oleracea) powder in flour dough as a natural antioxidant was investigated, and oxidation of frying oil and the lipid in fried products during frying was also studied. Flour dough with spinach powder was rolled into sheets of 0.1 cm thickness and then cut into squares to be fried. Each frying was performed in 160 degrees C soybean oil for 1 min, repeated every 20 min for 20 h. Fried samples were analyzed immediately or after being stored at 60 degrees C for 12 days under dark. The lipid content of fried dough was lower in samples with the addition of spinach powder. Spinach in the dough decreased accumulation of the polar compounds in soybean oil during frying but had little effect on the fried dough. It also reduced conjugated diene and aldehyde formation in the lipid of fried dough during storage. Improvement in lipid oxidative stability, presumably due to pigments in spinach, was more noticeable in the fried products during storage than in the frying oil.  相似文献   

10.
Starch is often added to batters to improve the texture and appearance of fried food products. However, comparisons of commercially available starches in terms of batter characteristics are rare. In this study, various corn starches, native or modified, were mixed with wheat flour (20% dry solids basis), and the physical properties of the batters after deep-fat frying were examined. Native corn starches of different amylose contents (high-amylose, normal, and waxy) and chemically modified corn starches (oxidized and cross-linked) were tested. The batter was prepared by adding water to the starch-flour mixtures (42% solids) and deep-fat frying at 180°C for 30 sec. The texture of the fried batter was analyzed using a texture analyzer (TA) with a Kramer shear cell. The pasting viscosity profile of the starch-flour mixtures (7% solids in water) was also measured with a Rapid Visco Analyser. When the native corn starches of different amylose contents were compared, the crispness (peak number before breakage) and hardness (maximum peak force) measured using the instrument were positively correlated with the amylose content in starches but negatively correlated with the residual moisture content of the fried batters. The peak viscosity and breakdown in viscosity profiles of the starch-flour mixtures were also negatively correlated with crispness. The use of high-amylose corn starch was effective not only in increasing the crispness, but also in reducing the oil uptake. However, the fried batter containing high-amylose starch was denser and harder than the batter containing normal starch. Among the modified starches tested, oxidized (0.4% active Cl2) and cross-linked (4% 99:1 mixture of STMP and STPP) starches showed improvements in the overall properties of the fried batters. With excessive oxidizations (>0.4% Cl2), however, the crispness was reduced.  相似文献   

11.
Sorghum (Sorghum bicolor (L.) Moench) grain was boiled or autoclaved in alkali, washed, drained, and dried into shelf-stable half-products (pellets). The pellets were deep-fat fried to produce a crunchy snack product. Effects of cooking time, drying method (pellet moisture content), and sorghum cultivar on unfried and fried pellets were evaluated. Increasing the alkaline cooking time from 30 to 60 min decreased the yield of the pellets from 96 to 84% (on a dry weight basis). Cooked sorghum dried at room temperature (24°C) for 18 hr, followed by oven-drying at 50°C for an additional 18 hr, produced pellets with a low moisture content (≤5%), that required a higher frying temperature (≥220°C). However, cooked sorghum dried at room temperature for 18 hr followed by oven-drying at 50°C for 5 hr produced pellets with 9% moisture and a lighterdensity highly acceptable product when fried at 220°C. Fat content of fried pellets averaged 18%. The optimum method for producing a light, crunchy, fried product was cooking for 60 min, drying to 9% moisture, and frying at 220°C. ATx631*Tx436, the hardest endosperm-texture sorghum used in the study, had the highest unfried and fried pellet yields. Dorado, an intermediate-to-soft endosperm-texture sorghum, and ATx Arg-1*Tx2907, a waxy sorghum, had lower yields. The fried pellets produced from Dorado and waxy sorghum (ATxArg-1*Tx2907) were more expanded than those produced from ATx631*Tx436.  相似文献   

12.
Three liquid chromatographic (LC) methods employing amperometric detection were compared with the collaboratively studied FDA optimized Monier-Williams distillation method for the determination of total sulfite in 5 food types. The foods included lemon juice, white wine, instant mashed potatoes, golden raisins, and onion flakes. Two of the LC methods (one employing headspace sampling and the other direct injection) used ion-exchange chromatography with a basic mobile phase (pH about 10.8) and a glassy carbon electrode; the third (employing direct injection) used ion-exclusion chromatography with an acidic mobile phase (pH about 2) and a platinum electrode. All 4 methods produced similar results for the wine, lemon juice, and raisins. Results were different for instant mashed potatoes and onion flakes. The headspace-LC method and direct ion-exclusion LC method, both of which employed an alkaline sample extraction, yielded significantly higher values for sulfite in instant potatoes than did the other 2 methods. A large interfering peak with both direct LC methods prevented quantitation of sulfite in the onion flakes. All methods can detect sulfite as low as about 1 microgram/g in 4 of 5 food types examined.  相似文献   

13.
Fate of fumonisins during the production of fried tortilla chips.   总被引：4，自引：0，他引：4  
The fate of fumonisin B(1) (FB(1)), a mycotoxin found in corn, during the commercial manufacture of fried tortilla chips was studied. FB(1) and hydrolyzed FB(1) (HFB(1)) concentrations in four lots of corn and in the masa, other intermediates, liquid and waste byproducts, and fried chips were determined by HPLC. FB(1) concentrations in the masa and chips were reduced significantly, up to 80% in the fried chips, compared to that in the raw corn. HFB(1) was also found in the masa and chips, but at low concentrations compared to FB(1). LC-MS analyses corroborated HPLC findings and further showed the presence of partially hydrolyzed FB(1) (PHFB(1)), which, like HFB(1), was formed during the nixtamalization (cooking/steeping the corn in alkaline water to make masa) step and found predominantly in the cooking/steeping liquid and solid waste. No significant amounts of N-(carboxymethyl)-FB(1) or N-(1-deoxy-D-fructos-1-yl)-FB(1), indicative of fumonisin-sugar adduct formation, were found. Thus, FB(1) is removed from corn and diverted into liquid and waste byproducts during the commercial production of fried tortilla chips. Nixtamalization and rinsing are the critical steps, whereas grinding, sheeting, baking, and frying the masa had little effect.  相似文献   

14.
Genotoxic heterocyclic amines (HAs) are formed via the Maillard reaction and free radical reaction mechanisms when meat or fish is cooked at usual cooking conditions. In this paper, the effect of the addition of red wine was tested to study if it interferes in HA formation. Fried chicken breast was the food item chosen, and three different red wines, characterized in terms of grape varieties, free amino acids, antioxidant properties, and metallic composition, were used to marinate meat prior to the heating process. Unmarinated samples and samples marinated with an ethanol-water mixture provided reference HA levels. The frying experiments were performed under well-controlled temperature and time conditions. The samples were analyzed for HA content using solid-phase extraction and LC-MS/MS. DMIP, PhIP, MeIQx, 4,8-DiMeIQx, IFP, TMIP, harman, and norharman were identified in fried chicken breast. Red wine marinades were found to reduce the formation of some of the HAs formed. PhIP, with a reduction of up to 88%, was the most minimized amine, although the formation of harman was enhanced.  相似文献   

15.
The effect of the type of frying culinary fat (olive oil, sunflower oil, butter, and pig lard) on volatile compounds isolated from fried pork loin chops (m. Longissimus dorsi) was measured by SPME-GC-MS. Frying modified the fatty acid composition of lipids from pork loin chops, which tended to be similar to that of the culinary fat used to fry. Volatile compounds formed from the oxidation of fatty acids increased, such as aldehydes, ketones, alcohols, and hydrocarbons. Besides, each culinary fat used modified the volatile profiles in fried meat differently. Sunflower oil-fried pork loin chops presented the highest aldehyde aliphatic content, probably due to their highest content of polyunsaturated acids. Hexanal, the most abundant aldehyde in fried samples, presented the most elevated content in sunflower oil-fried pork loin chops. In addition, these samples presented more heterocyclic compounds from the Maillard reaction than other fried samples. Volatiles detected in olive oil-fried pork loin chops were mainly lipid-derived compounds such as pentan-1-ol, hexanal, hept-2-enal, nonanal, decanal, benzaldehyde, and nonan-2-one. Butter-fried pork loins were abundant in ketones with a high number of carbons (heptan-2-one, nonan-2-one, undecan-2-one, tridecanone, and heptadecan-2-one). Pig lard-fried pork loin chops presented some Strecker aldehydes isolated in only these samples, such as 2-methylbutanal and 3-(methylthio)propanal, and a sulfur compound (dimethyl disulfide) related to Strecker aldehydes.  相似文献   

16.
A sensitive liquid chromatographic method has been developed for the simultaneous determination of oxytetracycline, minocycline, tetracycline, and doxycycline in serum. A serum sample is vortex-mixed with a solution of mobile phase for tetracyclines and 2% (v/v) phosphoric acid. The mixture is filtered using a 30,000 molecular weight cutoff microseparation tube which separates high-molecular-weight solutes following low-speed centrifugation. Tetracyclines are separated from other serum components by reverse phase liquid chromatography (LC) with buffered methanol mobile phase. Ultraviolet absorbance of the column effluent is monitored at 267 nm. Concentrations as low as 0.2 micrograms/mL of tetracyclines in serum are quantitatable, with recoveries from 76.2 to 102.6% and coefficients of variation from 2.69 to 5.36%. The method has been tested in bovine, porcine, equine, caprine, ovine, canine, feline, and avian (turkey) serum.  相似文献   

17.
The aim of this work was to examine the effect of blanching or soaking in different acid solutions on the acrylamide content in potato crisps. Furthermore, the effects of a shorter frying time and a lower frying temperature combined with a postdrying were investigated. Soaking or blanching of potato slices in acidic solutions decreased the pH of potato juice and increased the extraction of amino acids and sugars. Potato crisps obtained after such pretreatments were characterized by lower acrylamide content. The most effective extraction of free amino acids and sugars as well as the largest decrease of acrylamide content (90%) in crisps was obtained when potato slices were soaked in acetic acid solution for 60 min at 20 degrees C. Shorter frying time followed by postdrying resulted in low-moisture potato crisps. Furthermore, the postdrying treatment gave a decreases in acrylamide content of approximately 70% when potato slices were fried at 185 degrees C and approximately 80% when potato slices were fried at 160 degrees C. Effective ways of decreasing acrylamide content in crisps production have been found. Crisps with low acrylamide content and good sensory quality can be obtained either by blanching in acetic acid as pretreatment or by a short frying followed by postdrying.  相似文献   

18.
In this paper the relationship between virgin olive oil (VOO) phenol compounds and the formation of acrylamide in potato crisps was investigated. The phenol compositions of 20 VOO samples were screened by LC-MS, and 4 oils, characterized by different phenol compound patterns, were selected for frying experiments. Slices of potatoes were fried at 180 degrees C for 5, 10, and 15 min, and acrylamide content was determined by LC-MS. Results demonstrated that VOO phenolic compounds are not degraded during frying, and crisp color was not significantly different among the four VOOs. Acrylamide concentration in crisps increased during frying time, but the formation was faster in the oil having the lowest concentration of phenolic compounds. Moreover, the VOO having the highest concentration of ortho-diphenolic compounds is able to efficiently inhibit acrylamide formation in crisps from mild to moderate frying conditions. It was concluded that the use of ortho-diphenolic-rich VOOs can be proposed as a reliable mitigation strategy to reduce acrylamide formation in domestic deep-frying.  相似文献   

19.
LC/MS/MS characterization of phenolic constituents in dried plums   总被引：7，自引：0，他引：7  
Dried plums are known as a healthy food in the West and used as medicine in India. They have been characterized by high concentrations of phenolic compounds, which are believed to play a crucial role in protection against various age-related diseases. Liquid chromatography/mass spectrometry/mass spectrometry (LC/MS/MS) with four different conditions was used to analyze the phytochemicals in commercial dried plums. The major components were neochlorogenic acid and cryptochlorogenic acid. Forty minor components were characterized by their MS/MS spectra and LC retention time. Six of them are novel ester isomers formed by two caffeic acids and one quinic acid. The diagnostic fragmentation patterns of different phenolics are presented on the basis of electrospray ionization (ESI) MS/MS data of components in dried plums and fourteen authentic standards.  相似文献   

20.
An aqueous slurry of gamma-irradiated sterilized dried figs was inoculated with toxigenic strains of Aspergillus flavus and Aspergillus parasiticus. During incubation at 28 degrees C, pH, fructose, glucose, and free amino acids were determined by high-performance liquid chromatography and liquid chromatography (LC)/mass spectrometry, respectively, over 13 time points (1-20 days). At the same 13 time points using a LC/time-of-flight mass spectrometry screening method, aflatoxin B 1 and other secondary metabolites were simultaneously monitored. During the course of incubation, the pH significantly decreased and aflatoxin B 1 formation correlated with a reduction in proline content for both fungi. Of the 22 free amino acids that were monitored, only proline and cystine were found to be critical in supporting aflatoxin production. Levels of fructose and glucose steadily declined during incubation, until glucose was almost exhausted after 21 days. These time-course experiments confirmed the need for carbon and nitrogen sources for aflatoxin production in dried figs, and the favorable composition of figs as a fungal growth medium.  相似文献   

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