Hazard analysis and critical control points in deep‐fat frying

The Hazard Analysis and Critical Control Point (HACCP) system was applied to sunflower oils used for frying in nineteen university restaurants. Guidelines for implementation that include training personnel, flow diagram, identifying hazards, controlling hazards at critical control points (CCP's), monitoring CCP's and measure of action for exceeding limit were developed. Polar compounds were used as a measure for deteriorated sunflower oil and the values obtained from university restaurants before and after personnel training and implementation of HACCP were determined. Implementation of the guidelines produced an improvement in the quality of the frying process, and all establishments reduced their polar compound values to less than 25% by mass.     

食品安全性与HACCP

食品安全是当前世界范围内存在的重要问题 ,保证食品的安全对人类健康十分必要。HACCP体系是一种预防性的质量控制体系 ,对建立现代食品安全系统具有重要的指导意义。主要讨论目前食品安全性存在的问题 ,并介绍了HACCP体系在食品安全方面的应用     

Antioxidant efficiency of oregano in frying and storage of fried products

The effect of oregano on the oxidative stability of cottonseed oil during frying of potato chips and on the storage stability of the products was studied. The ground spice or an ethanol‐derived extract was added to the oil before frying. The results showed that both additives decreased the rates of accumulation of conjugated dienes, polar compounds, polymerized triacylglycerols, dimeric triacylglycerols and the p‐anisidine value of the frying oil, while the hydrolytic compounds were not affected. The major decrease was observed in the accumulation of polymerized and dimeric triacylglycerols. The storage stability of the produced chips was estimated by the rate of increase of the peroxide value and of the conjugated dienes in the oil absorbed by them. Both rates were depressed when oregano was added to the frying oil, with the protective action of oregano extract being considerably greater than that of ground oregano. The protective action of oregano extracts obtained by successive extractions with petroleum ether (PE), diethyl ether (EE) and ethanol (EtOH) and added to the chips after frying was also examined. The results showed that the EE and EtOH extracts were very effective against oxidative deterioration.     

Addition of ferulic acid,ethyl ferulate,and feruloylated monoacyl- and diacylglycerols to salad oils and frying oils

To determine antioxidative effects of ferulic acid and esterified ferulic acids, these compounds were added to soybean oils (SBO), which were evaluated for oxidative stability and frying stability. Additives included feruloylated MAG and DAG (FMG/FDG), ferulic acid, ethyl ferulate, and TBHQ. After frying tests with potato chips, oils were analyzed for retention of additives and polar compounds. Chips were evaluated for hexanal and rancid odor. After 15 h frying, 71% of FMG/FDG was retained, whereas 55% of ethyl ferulate was retained. TBHQ and ferulic acid levels were 6% and <1%, respectively. Frying oils with ethyl ferulate or TBHQ produced significantly less polar compounds than SBO with no additives. Chips fried in SBO with TBHQ or ferulic acid had significantly lower amounts of hexanal and significantly less rancid odor after 8 d at 60°C than other samples. Oils were also aged at 60°C, and stability was analyzed by PV, hexanal, and rancid odor. Oils with TBHQ or FMG/FDG had significantly less peroxides and hexanal, and a lower rancid odor intensity than the control. FMG/FDG inhibited deterioration at 60°C, whereas ethyl ferulate inhibited the formation of polar compounds in frying oil. Ferulic acid acted as an antioxidant in aged fried food. TBHQ inhibited oil degradation at both temperatures. Presented at the 94th AOCS Meeting & Expo, Kansas City, MO, May 4–7, 2003.     

Effect of fatty acid composition of oils on flavor and stability of fried foods

Effects of fatty acid composition of frying oils on intensities of fried-food flavor and off-flavors in potato chips and french-fried potatoes were determined. Commercially processed cottonseed oil (CSO) and high-oleic sunflower oil (HOSUN) were blended to produce oils with 12 to 55% linoleic acid and 16 to 78% oleic acid. Analytical sensory panels evaluated french-fried potatoes and pilot plant-processed potato chips. Initially, both foods prepared in CSO (16% oleic/55% linoleic acid) had the highest intensities of fried-food flavor; however, this positive flavor decreased with decreasing levels of linoleic acid. 2,4-Decadienal in potato chips also decreased with decreasing linoleic acid in the oils. Frying oil stability, measured by total polar compounds (TPC), and oxidative stability of potato chips, measured by volatile compounds, showed that HOSUN (78% oleic acid) produced the lowest levels of TPC and the lowest levels of hexanal and pentanal, indicating greater frying oil stability and oxidative stability of the food. However, fresh potato chips fried in HOSUN had the lowest intensities of fried-food flavor and lowest overall flavor quality. Fried-food flavor intensity was the best indicator of overall flavor quality in fresh potato chips. Volatile compounds, TPC, and oxidative stability index directly varied with increasing oleic acid, and were therefore not directly indicative of flavor quality. No oil analysis predicted flavor stability of aged potato chips. Compositions of 16 to 42% oleic acid and 37 to 55% linoleic acid produced fresh fried-food with moderate fried food flavor intensity, good overall flavor quality, and low to moderate TPC levels (chips only). However, in aged food or food fried in deteriorated oil, compositions of 42 to 63% oleic and 23 to 37% linoleic provided the best flavor stability.     

Acrylamide in heated potato products – analytics and formation routes

Acrylamide is a highly polar, water‐soluble molecule with low, but significant volatility. Most common methods for determination of acrylamide are high performance liquid chromatography‐tandem mass spectrometry (LC‐MS‐MS), gas chromatography‐mass spectrometry (GC‐MS) after bromination, GC‐MS without and LC‐MS after derivatisation with mercaptobenzoic acid. The different clean‐up procedures used are presented and the advantages and disadvantages of the individual methods are discussed. Acrylamide is formed during food preparation if free asparagine and reducing sugars are present, water activity is low and the product temperature exceeds 100 °C. The influence of different parameters on acrylamide formation in model systems is discussed. In fried potatoes the greatest amount of acrylamide is formed from asparagine and reducing sugars. Alternative routes of formation, as for example via acrolein and acrylic acid are much less important.     

Factors affecting the concentration of acrylamide during deep‐fat frying of potatoes

The paper describes the effect of different factors influencing the concentration of acrylamide in deep‐fat fried potato products. In French fries the amount of acrylamide increased with the temperature as well as the frying time, especially at temperatures higher than 175 °C. The increase of acrylamide with the time followed a linear function, whereas a non‐linear relationship was given with the temperature of frying. As a result, a reduction of the processing temperature led to lower concentrations of acrylamide in the product. Both, oil type and silicon oil as antifoaming agents had no significant influence upon the acrylamide concentration in the food. The variety of potatoes had a strong effect on the acrylamide concentration in potato crisps and French fries. The investigation showed a significant correlation (r = 0.73) between the concentration of acrylamide and reducing sugars in raw potatoes, and no significant correlation with the asparagine concentration. The storage temperature of the raw material had an effect on the acrylamide concentration in the product. Lowering of the storage temperature from 8 to 4 °C resulted in an increase of the concentration of reducing sugars in the raw material, which led to a higher potential of acrylamide formation in the products. The experiments showed that the acrylamide concentration of French fries depended on the surface‐to‐volume ratio (SVR).     

Comparison of flavor compounds of potato chips fried in palmolein and silicone fluid

The importance of the frying oil as a heat-transfer medium and as a source of flavor precursors for the formation of potato chip flavor was investigated. Potato slices were fried in palmolein or silicone fluid, and the volatile flavor compounds of the resulting chips were isolated onto Tenax and analyzed by gas chromatography-mass spectrometry. Although the heat-transfer coefficients of the oils did not differ significantly, their temperature profiles during frying were different, probably due to greater turbulence on placing potato slices in palmolein, leading to more efficient heat transfer. Levels of Strecker aldehydes and sulfides in chips fried in the two media were not significantly different, but levels of pyrazines were significantly higher in palmolein-fried chips. Amounts of 2,4-decadienal were also significantly higher in palmolein-fried chips, but there was no significant difference in hexanal levels between the samples.     

苯胺生产过程的危险分析与安全对策

苯胺作为重要的有机化工中间体,其安全生产具有一定的典型性.本文介绍了苯胺生产的工艺流程,对其生产过程中的介质危险、过程危险及装置危险,结合事故案例进行剖析,提出了保障苯胺装置安全生产的具体措施.     

球罐开罐检验分析及球罐的安全质量控制

通过对兴平化肥厂 6 0 0m3 液氨球罐历次全面定期检验中发现的缺陷分析 ,指出了球罐主要缺陷及其产生的条件和机理 ,从制造工艺控制、运行中介质有害物质的控制及水压试验等几方面 ,论述了球罐质量控制的问题 ,提出了预防主要危害缺陷的方法     

Cyclohexa‐3,5‐diene‐1,2‐trans‐diols – Synthesis and Application in Target‐Oriented Syntheses

An exhaustive overview of the field of cyclohexa‐3,5‐diene‐1,2‐trans‐diols is given. Early and recent methods for the formation of the compounds are reviewed and the various syntheses in which the title compounds have been applied are presented. Special emphasis is given to naturally occurring epoxides, which have been the dominant target molecules since the 1970s. Finally, recent advances in biotechnology are highlighted; with the increased availability of the enantiomerically pure cyclohexa‐3,5‐diene‐1,2‐trans‐diols, new synthetic endeavours were initiated.     

Content of trans,trans‐2,4‐decadienal in deep‐fried and pan‐fried potatoes

Trans,trans‐2,4‐decadienal is a by‐product of frying oil that is also transferred to fried food. This aldehyde has been found and quantified both in frying oils and fumes generated during frying. Furthermore, it has been reported that 2,4‐decadienal has cytotoxic and genotoxic effects and promotes LDL oxidation. In the present work trans,trans‐2,4‐decadienal was detected directly in fried potatoes (french‐fries). Moreover, the influence of frying conditions (deep‐frying, pan‐frying), the oil type (olive oil, sunflower oil, cottonseed oil, palm oil and a vegetable shortening) and the degree of thermal deterioration (eight successive frying sessions without replenishment) on the production of 2,4‐decadienal in oil and potatoes was studied. The isolation of the aldehyde was performed by methanol extraction, while the identification and quantification was performed by RP‐HPLC. The quantity of trans,trans‐2,4‐decadienal produced during successive pan‐frying demonstrated a peak at the third and fourth frying session. The highest concentration of trans,trans‐2,4‐decadienal was detected in potatoes fried in sunflower oil, and the lowest in olive oil. The quantity of trans,trans‐2,4‐decadienal in fried potatoes decreased during successive deep‐frying at the seventh frying session or remained stable, except for cottonseed oil. The quantity of trans,trans‐2,4‐decadienal in fried potatoes was considered to be dependent on the oil used, on the frying process and, to a lesser extent, on the oil deterioration. In all cases tested, the highest concentration of trans,trans‐2,4‐decadienal was detected during deep‐frying. The unsaturation degree of the frying oil was considered to promote the formation of trans,trans‐2,4‐decadienal. Considering the quantity of 2,4‐decadienal found in french‐fries and in the respective frying medium, direct quantification of 2,4‐decadienal is required in order to make an estimation of intake from french‐fries.     

化工工艺设计中安全风险识别及控制

在分析化工工艺设计流程及产生工艺风险因素的基础上,提出了化工工艺设计中安全风险识别及控制的必要性和对策建议,对提升化工项目生产安全水平具有积极的现实意义。     

Use optimization of natural antioxidants in refined, bleached, and deodorized palm olein during repeated deep-fat frying using response surface methodology

An optimization study on the use of oleoresin rosemary extract, sage extract, and citric acid added into refined, bleached, and deodorized (RBD) palm olein in deep-fat frying of potato chips was carried out using response surface methodology (RSM). Results showed that oleoresin rosemary extract was the most important factor affecting the sensory acceptability of potato chips. For taste and odor, its effects were highly significant (P<0.01), while for crispiness and overall acceptability, the effects were significant (P<0.05). As for sage extract, the level of this antioxidant had a highly significant (P<0.01) effect on appearance and taste and a significant effect (P<0.05) on odor and overall acceptability, but had no effect on crispiness. Although there was no significant synergistic correlation between citric acid and oleoresin rosemary extract or sage extract at the first order, its second order was significantly (P<0.05) related to taste, crispiness, and overall acceptability. An interaction between oleoresin rosemary and sage extracts also significantly (P<0.05) improved the score of overall acceptability of the potato chips. Contour maps of the sensory scores of potato chips indicated that the optimal points for appearance were achieved using 0.062% oleoresin rosemary extract, 0.066% sage extract, and 0.023% citric acid, while optimal task was achieved with 0.063% oleoresin rosemary extract, 0.075% sage extract, and 0.025% citric acid. With the same sequence of ingredients added into oil, the combinations required to achieve the optimal odor, crispiness, and overall acceptability scores were 0.058-0.046-0.026, 0.060-0.071-0.022, and 0.060-0.064-0.026%, respectively.     

Direct determination of aluminium in foods and pharmaceutical preparations by potentiometry using an AlMCM-41 modified polymeric membrane sensor

A potentiometric aluminium sensor, based on the use AlMCM-41 as a neutral carrier, in poly(vinyl chloride) (PVC) matrix, is reported. The sensor exhibits significantly enhanced selectivity toward Al³⁺ ions over the concentration range 1.0 × 10⁻⁷ to 1.0 × 10⁻¹ M with a detection limit of 8.6 × 10⁻⁸ M and a Nernstian slope of 19.5 ± 0.4 mV/decade of activity. The best performance was obtained with membrane composition 30% poly(vinyl chloride), 67% acetophenone, 3% ionophore and 2 mL tetrahydrofuran. Fast and stable response, good reproducibility and long-term stability are demonstrated. The response time of the sensor is ∼10 s and membrane could be used over a period of 3 months without any considerable divergence in potentials. Selectivity coefficients were determined by matched potential method (MPM). The AlMCM-41-based sensor is suitable for use in aqueous solution of pH 3-6. The standard electrode potentials were determined at different temperatures and used to calculate the isothermal coefficient of the electrode. It was used to determine Al³⁺ in drugs and food products.     

氯乙烯聚合安全设计与安全生产控制

介绍了聚氯乙烯装置中存在的大量危险化学品,在氯乙烯聚合安全设计中如何优化技术方案以及采取的安全可靠措施。     

Frying quality and stability of low-and ultra-low-linolenic acid soybean oils

To determine effects of very low levels of linolenic acid on frying stabilities of soybean oils, tests were conducted with 2% (low) linolenic acid soybean oil (LLSBO) and 0.8% (ultra-low) linolenic acid soybean oil (ULLSBO) in comparison with cottonseed oil (CSO). Potato chips were fried in the oils for a total of 25 h of oil use. No significant differences were found for either total polar compounds or FFA between samples of LLSBO and ULLSBO; however, CSO had significantly higher percentage of polar compounds and FFA than the soybean oils at all sampling times. Flavor evaluations of fresh and aged (1, 3, 5, and 7 wk at 25°C) potato chips showed some differences between potato chips fried in different oil types. Sensory panel judges reported that potato chips fried in ULLSBO and aged for 3 or 7 wk at 25°C had significantly lower intensities of fishy flavor than did potato chips fried in LLSBO with the same conditions. Potato chips fried in ULLSBO that had been used for 5 h and then aged 7 wk at 25°C had significantly better quality than did potato chips fried 5 h in LLSBO and aged under the same conditions. Hexanal was significantly higher in the 5-h LLSBO sample than in potato chips fried 5 h in ULLSBO. The decrease in linolenic acid from 2 to 0.8% in the oils improved flavor quality and oxidative stability of some of the potato chip samples.     

乙炔工艺系统安全控制研究与应用

通过对乙炔生产装置中出现的一些制约乙炔安全生产的异常问题进行了相关改进与处理,同时对产生的原因及综合处理方案进行了优化选择,提出合理有效的解决方案,并结合生产特点与自身的生产实际,采取经济有效的处理方案,实现了乙炔系统安全生产过程的优化与提升。