Cause of bisphenol A migration from cans for drinks and assessment of improved cans

In the previous investigation, we found that some cans for coffee and black tea drinks released large amounts of bisphenol A (BPA) into their contents. Equivalent cans were obtained and the cause of BPA migration was investigated. Equivalent cans A, B and D contained high levels of BPA in the side seam, in the bottom, and in the bottom and the side seam, respectively, while can C contained some level of BPA in the body, which has a large area, therefore, all of them contained high amounts of BPA in their coatings. In the migration test, there was no BPA migration from the cans into water at 60 and 95 degrees C for 30 min, into 20% ethanol at 60 degrees C for 30 min, or into n-heptane at 25 degrees C for 60 min. However, at 120 degrees C for 30 min, equivalent cans released 35-124 ng/mL BPA into the water. The total migration was similar to the total residues of BPA in the can coating and was close to the total amount of BPA in the drinks. Thus, BPA migration from the can coating requires heating to more than 105 degrees C, which is the glass transition temperature of the epoxy resin. Improved cans which contained less than 1/10 as much BPA as the equivalent cans showed very low migration levels, i.e., 3-6 ng/mL.     

Migration of bisphenol A (BPA) from can coatings into a fatty-food simulant and tuna fish.

The effect of heat processing, storage time and temperature on the migration of bisphenol A (BPA) from organosol and epoxy can coatings to a fatty-food simulant and tuna was determined. Analyses of BPA were performed by RP-HPLC with fluorescence detection. Four migration experiments, performed between 2000 and 2003, using cans with organosol, epoxy and a combination of both types of coatings were performed under different processing conditions and storage times. Migration levels as high as 646.5 microg kg(-1) BPA from an organosol coating of tuna fish cans were found using a fatty-food simulant following the heat processing of the simulant-filled cans. Levels ranging from 11.3 to 138.4 microg kg(-1) BPA from tuna cans coated with an epoxy resin migrated to the fatty-food simulant during 1 year at 25 degrees C. Levels of BPA migration into a fatty-food simulant from thermally processed and stored tuna cans coated with a combination of organosol and epoxy resins and from vegetable cans coated with an epoxy resin were below the limit of quantitation of 10.0 microg kg(-1). Migration of BPA to tuna ranged from <7.1 to 105.4 microg kg(-1) during long-term storage at 25 degrees C. BPA levels in tuna cans purchased from three local supermarkets ranged from <7.1 to 102.7 microg kg(-1). The highest migration levels were found following heat processing at temperatures as high as 121 degrees C and at times as long as 90 min. Coatings from different can batches can give different levels of BPA migration. The migration levels of BPA found in this work are below the present European Union migration limit, except the 646.5 microg kg(-1) found after the commercial heating process was applied to the simulant-filled cans coated with the organosol resin.     

Migration of bisphenol A from can coatings—effects of damage, storage conditions and heating

Bisphenol A (BPA) is an important monomer used in the manufacture of epoxy resins for internal food can linings. Experiments were conducted to investigate the effects of different storage conditions and can damage on the migration of BPA to foods. These experiments were conducted in a systematic fashion by filling empty epoxyphenolic coated cans with four foods: soup, minced beef, evaporated milk and carrots and a food simulant (10% ethanol). Filled cans of each food type or simulant were then sealed and processed using appropriate conditions, before storage at three different temperatures: 5°C, 20°C and 40°C. For each of the storage regimes, 50% of the cans were dented to establish if this would lead to increased BPA migration. Cans were removed from these stocks at intervals of 1, 3 and 9 months storage at 5°C and 20°C or 10 days, 1 and 3 months at 40°C. Some initial problems of heterogeneity between samples was overcome by determining the amount of BPA in food as well as in the can lining. It was found that 80-100% of the total BPA present in the coating had migrated to foods directly after can processing by pilot plant filling with food or simulant, sealing and sterilization. This level was not changed by extended storage (up to 9 months) or can damage, indicating most migration was occurring during the can processing step. There was no noticeable difference, in this respect, between the different foods or the food simulant. Analysis of control samples (foods fortified with ∼0.1 mg kg^-1 BPA and contained in Schott bottles) showed that BPA was stable under both processing and storage. Experiments were also conducted to investigate the potential effects, on the migration of BPA from can coatings, of cooking or heating foods in the can prior to consumption. Food cans were purchased and the food either cooked or heated in the can. BPA was analysed prior to and after the heating/cooking process. It was concluded from the results that there were no appreciable differences in the BPA level before and after cooking or heating.     

A study of the evolution of the physicochemical and structural characteristics of olive and sunflower oils after heating at frying temperatures

The evolution of the density, viscosity, oil/water interfacial tension and structure of vegetable oils after heating at frying temperatures was studied to explore the possibility of reusing waste vegetable oils as solid agglomerants for different purposes. Commercial olive and sunflower oils were heated at 150 and 225 °C in the time interval of 1–15 days to achieve a wide range of alteration degrees. Structural changes in the oils were monitored by FT-IR and ¹H NMR. Significant variations occur in the physicochemical and structural characteristics of these oils, which may affect their agglomeration capability, when they were heated at frying temperatures for periods above two days. Under these conditions, the viscosity of the oils increased very quickly, whereas their unsaturation degree decreased noticeably. Decreases in the relative intensities of the NMR spectra signals of the unsaturation-related protons were observed, those corresponding to the diallyl protons occurring much faster. Of the two vegetable oils studied, sunflower oil was found to be more sensitive to thermal treatment, undergoing greater changes in its properties, especially in viscosity, which may show a marked increase.     

Bisphenol A (BPA) and its source in foods in Japanese markets

The determination of bisphenol A (BPA) and/or bisphenol A diglycidyl ether (BADGE) in foods sold in Japanese markets and in water leached from six epoxy resin cans with similar diameters was carried out using high-performance liquid chromatography (HPLC) with electrochemical detection (LC/ECD), LC-mass spectrometric detection (LC/MS) and LC-tandem mass spectrometric detection (LC/MS/MS). BPA concentrations were 0-842 ng g^-1 for 48 canned foods, 0-14 ng g^-1 for 23 foods in plastic containers, and 0-1 ng g^-1 for 16 foods in paper containers. No BADGE was detected in three canned foods. There was no difference in leaching concentrations of BPA into glycine buffers at pHs 8 and 11, and water. The amounts of BPA leached into water from six epoxy resin cans held at 121°C for 20 min were almost the same as the cans' contents and were much higher than the amounts leached from cans held at or below 80°C for 60 min. The amount leached depended on the type of can, but not on the amount of BADGE leached from the cans. Considerably more BPA than BADGE leached to water from six cans. Two cans whose contents had high concentrations of BPA showed no BADGE leaching even at 121°C, suggesting the different kinds of epoxy resin can linings from others. The results imply that the main source of human exposure to BPA is food from cans with linings that contain high percentages of BPA as an additive or an unforeseen contaminant.     

Heat Transfer Study on Flame Pasteurization of Liquids in Aluminum Cans

Heat transfer studies were performed in 209 × 413 aluminum cans using 1% bentonite suspension. The cans were heated in a pilot flame sterilizer. The temperature profile was practically uniform radially and axially after 4.5 min of heating. The slowest heating was experienced in the bottom (heel) of these cans. The temperature difference between the slowest heating point and the hot region over the flame decreased as the can was heated: from 15.6°C after 1 min to 6.7°C after 4.5 min of heating. The internal heat transfer coefficient at 40 rpm was measured and showed an increase with heating time.     

Stability of haem pigments in model systems and cooked meat

The stability of sheep haemoglobin and myoglobin in aqueous solution at 80, 100 and 121°C for 1 h was measured by subjecting portions of the heated solutions to electrospray mass spectrometry (ESMS). ESMS dissociates haem proteins into the globin chains and the haem moiety and, with haemoglobin, degradation of the α-(15047·5 Da) and β-(16073·3 Da) chains was observed at all heating temperatures. Under the same conditions, sheep myoglobin dissociated into the globin (16923·2 Da) and haem parts but the globin was stable and few degradation products were observed in the ESMS trace (mass range 4-20 kDa) even after 1 h at 121°C. There did seem to be limited breakdown of the globin due to loss of 170 Da. From the amino acid sequence, it is postulated that this is due to loss of GLY-LEU from the N-terminus. Methods for extracting myoglobin from raw and cooked meat were then investigated. Water was adequate for myoglobin extraction from raw meat but urea solution was required for adequate extraction of cooked meat samples. Sheep meat was heated at 80, 100 and 121°C in sealed cans, extracted and the mass profile in the range 4-20 kDa measured. Myoglobin was the major peak when samples were heated for 10, 20, 30 and 40 min. After that time, other peaks appeared although the myoglobin globin chain was still apparent. The results are discussed in relation to using myoglobin as a marker for meat speciation.     

Effect of environmental parameters on growth kinetics of Bacillus cereus (ATCC 7004) after mild heat treatment

The influence of temperature (10 to 50 degrees C), initial pH (4.0 to 6.0) and sodium chloride concentration (0.5 to 3.0%) on the growth in nutrient broth and in meat extract of Bacillus cereus after mild heat treatment (90 degrees C--10 min) was determined. B. cereus spores survived after heating and they were able to germinate and grow in both media when post-treatment conditions were favourable. Heated B. cereus did not grow at 10 and 50 degrees C or in a medium with pH 4.0. Decreasing pH values and increasing levels of sodium chloride decreased growth rate and increased the lag phase of B. cereus. pH 4.5 was unable to prevent the growth of heated spores in a meat substrate with 0.5% NaCl at 12 degrees C. The combination of pH /=1.0% and temperatures /=60 degrees C could control heated B. cereus ATCC 7004 growth.     

常规加热和微波加热对两种植物油维生素E含量的影响

目的 研究常规加热和微波加热两种加热方式对植物油中维生素E的8种异构体的影响。方法 大豆油、棕榈油进行常规加热和微波加热后, 用异辛烷进行超声提取, 最后用正相高压液相色谱法测定。结果 两种加热方式都会使植物油中维生素E的含量降低, 其中微波加热对维生素E的影响更大。结论 加热时间过长会影响植物油的品质, 同时也能通过对植物油中维生素E的检测推论该植物油是否经过加热处理。     

皂化-冷冻-萃取法研究加热或长期放置对植物油中短链脂肪酸含量的影响

为研究加热或长期放置对植物油中短链脂肪酸含量的影响,采用皂化-冷冻-萃取法分离除去植物油中的高级脂肪酸等干扰成分,采用气相色谱法(GC-FID)对植物油加热或长期放置后的短链脂肪酸含量进行了分析测定。结果表明:长期放置及加热的植物油中均检出了己酸、庚酸、辛酸3种短链脂肪酸,而正常植物油中未检出;短链脂肪酸含量随植物油加热温度升高、放置时间延长增加,其存在可用于表征植物油发生了氧化劣变;此外,反复加热及水洗不能去除这些短链脂肪酸,因而短链脂肪酸有望作为植物油品质评价的辅助指标。     

植物油种类对聚氯乙烯中环氧大豆油迁移的影响研究

目的 为探究植物油种类对聚氯乙烯(PVC)中环氧大豆油(ESBO)迁移的影响。方法 本文利用气相色谱-质谱联用法对PVC中ESBO向不同植物油中的迁移量进行表征。结果 该方法对所研究的植物油都适用,并可对5 mg/kg - 100 mg/kg浓度范围内的ESBO进行准确定量,平均回收率在93.0% - 107.3%之间,相对标准偏差(RSD%)为1.0% - 6.6%。迁移试验结果显示,ESBO在不同植物油中的迁移趋势相同,即为当迁移时间相同时,迁移量随着迁移温度的增加而增加;迁移温度相同时,迁移量随着迁移时间的增加先增大后达到平衡。当迁移温度为20 _^oC和40 _^oC时,达到迁移平衡需要15天左右;当迁移温度为60 _^oC时,达到迁移平衡需要20天左右。从迁移量数值上来看,ESBO在橄榄油中的迁移能力较椰子油中的小,但是与玉米油、芝麻油、菜籽油和大豆油中的相当。结论 除了迁移试验温度和时间外,植物油种类对ESBO的迁移也有着重要影响,以橄榄油为食品模拟物并不能完全代表ESBO在其他植物油中的迁移。     

Maillard Reaction Products as Encapsulants for Fish Oil Powders

The use of Maillard reaction products for encapsulation of fish oil was investigated. Fish oil was emulsified with heated aqueous mixtures comprising a protein source (Na caseinate, whey protein isolate, soy protein isolate, or skim milk powder) and carbohydrates (glucose, dried glucose syrup, oligosaccharide) and spray‐dried for the production of 50% oil powders. The extent of the Maillard reaction was monitored using L*, a*, b* values and absorbance at 465 nm. Encapsulation efficiency was gauged by measurement of solvent‐extractable fat and the oxidative stability of the fish oil powder, which was determined by assessment of headspace propanal after storage of powders at 35 °C for 4 wk. Increasing the heat treatment (60 °C to 100 °C for 30 to 90 min) of sodium caseinate‐glucose‐glucose syrup mixtures increased Maillard browning but did not change their encapsulation efficiency. The encapsulation efficiency of all heated sodium caseinate‐glucose‐glucose syrup mixtures was high, as indicated by the low solvent‐extractable fat in powder (<2% powder, w/w). However, increasing the severity of the heat treatment of the sodium caseinate‐glucose‐glucose syrup mixtures reduced the susceptibility of the fish oil powder to oxidation. The increased protection afforded to fish oil in powders by increasing the temperature‐time treatment of protein‐carbohydrate mixtures before emulsification and drying was observed irrespective of the protein (sodium caseinate, whey protein isolate, soy protein isolate, or skim milk powder) and carbohydrate (glucose, glucose/dried glucose syrup, or oligosaccharide/dried glucose syrup) sources used in the formulation. Maillard reaction products produced by heat treatment of aqueous protein‐carbohydrate mixtures were effective for protecting microencapsulated fish oil and other oils (evening primrose oil, milk fat) from oxidation.     

Effect of heating oils and fats in containers of different materials on their trans fatty acid content

BACKGROUND: The nature of the container material and temperature employed for deep‐frying can have an influence on the development of trans fatty acids (TFAs) in the fat used. The present study was undertaken to determine the effect of heating vegetable oils and partially hydrogenated vegetable fats with different initial TFA content in stainless steel, Hindalium (an aluminium alloy), cast iron and glass containers. Ground nut oil (oil 1), refined, bleached and deodorised (RBD) palmolein (oil 2) and two partially hydrogenated vegetable oils with low (fat 1) and high (fat 2) TFA content were uniformly heated at 175–185 °C over a period of 12 h. RESULTS: An increase in TFA content to 20 g kg^?1 was observed in oil 2 in the cast iron container, while a decrease in TFA content of 20–30 g kg^?1 was observed in fat 2 in all containers. The heating process of fats and oils also led to an increase in Butyro refractometer reading and colour values. CONCLUSION: This study showed that the TFA 18:1t content of oil 1, oil 2 and fat 1 increased with repeated or prolonged heating. The cast iron container showed the highest increase in TFA 18:1t for RBD palmolein (oil 2). The amount of linoleic acid trans isomers formed in the heating process was negligible. Fat 2 with high initial TFA content showed a decrease in TFA 18:1 and 18:2 on heating in all containers. Oils heated in glass and stainless steel containers showed less TFA 18:1t formation. Copyright © 2012 Society of Chemical Industry     

Simulation of migration from a multi-layer laminated film intended for retort foods

Migration from multi-layer laminated film pouches intended for retort foods was investigated through HPLC analysis with a fluorescence detector, and measurements of residue on evaporation, consumption of potassium permanganate and total organic carbon. HPLC analysis revealed that the levels of migrants in oil and the water which were heated in the pouches (121 degrees C, 30 min) were ten times of those in the corresponding official simulants under the official conditions; n-heptane (25 degrees C, 60 min), and water (95 degrees C, 30 min). Bisphenol A diglycidyl ether and related compounds were found in the oil and the water heated in the pouches, as well as in the simulants. These compounds were thought to have been present in the adhesive between the laminated films, and migrated through the food-contact film of the package. Consumption of potassium permanganate and residue on evaporation of the heated water were ten times of those of the water simulant, while the total organic carbon level of the heated water was several-hold greater than that of the water simulant. In addition, migrant levels per surface area of the pouch were one-fourth of the concentrations per content volume of the pouch. Since compliance with the legal limits is evaluated based on the concentration per surface area, real migration into foods would be underestimated by a factor of another four.     

Antiyeast Activity of Heated Garlic in the Absence of Alliinase Enzyme Action

Garlic heated to 121 °C was found to strongly inhibit the growth of yeasts, but not that of bacteria. The potency and stability of the antiyeast activity of heated garlic were compared with those of fresh garlic, garlic oil, and allyl isothiocyanate. The inhibitory activity of heated garlic was stable, and the minimum inhibitory concentration did not change for up to 30 d at 37 °C. The antiyeast activity of heated garlic was not influenced by pH. Alliin heated in distilled water showed an antiyeast activity pattern similar to that of heated garlic, suggesting that the compound(s) thermally generated from alliin are the principal antiyeast compound(s) of heated garlic. The antiyeast activity was increased as time of heating increased up to 45 min at 121 °C, and the activity did not change when garlic was further heated for up to 120 min.     

Comparison of microwave irradiation and conventional thermal heating on volatile profiles and degree of oxidation in corn oil

Volatile profiles and degree of oxidation in corn oils after microwave treatment for 50 min were compared to oils with conventional heating at 180°C for 4 h. Oil microwaved for 10 and 50 min showed a similar degree of oxidation compared to the oil heated at 180°C for 1 and 3 h, respectively, based on the primary and secondary oxidation products. However, the total volatile contents of 50 min-microwaved oil were significantly lower than that of corn oil heated for 1 h at 180°C (P < 0.05). Microwave treatment accelerated the rates of lipid oxidation by 4.6 times compared to 180°C thermal oxidation. Relatively short treatment with microwave irradiation may not provide sufficient time to generate volatiles from oil. Microwaved corn oil for 50 min had higher contents of hexanal and t-2-heptenal and lower contents of 2,4-decadienal and nonanal than the oils heated at 180°C for 3 h. Reactive oxygen species may be involved in volatile formation in microwave-irradiated oils.     

INSTABILITY OF SODIUM NITRITE IN A CHEMICALLY DEFINED MICROBIOLOGICAL MEDIUM

Mixtures of sodium nitrite, amino acids and ascorbic acid at pH 6.3 or 7.2 were filter sterilized or heated for various times at 121°C. Samples were analyzed for nitrite concentration immediately after treatment and after storage at 37 or 43°C. Heating the complete medium for 15 min at 121°C reduced the nitrite concentration by 30–50% independent of the initial nitrite concentration. Storage of complete filter sterilized medium at 43°C for 18–24 hr resulted in 50–65% loss of nitrite while in heat sterilized medium the loss was as great as 90%. None of the 19 amino acids stored individually with sodium nitrite at 37°C for up to 4 hr affected the nitrite concentration, whereas ascorbic acid resulted in total disappearance of nitrite. During heating at 121°C of the 19 amino acids only cystine resulted in any significant nitrite loss after 15 min of treatment while ascorbic acid effected total nitrite disappearance after 5 min. The defined medium containing nitrite demonstrated inhibitory activity against seven strains of Clostridium perfringens.     

微波对特种植物油品质的影响

对菜籽油、芝麻油、玉米油 3种特种植物油进行微波加热和常规加热处理 ,与不加热时的样品进行比较 ,并通过检测其酸价和过氧化值 ,研究了微波加热对其品质的影响 ,同时也探讨了油脂中添加VE 对其加热品质的影响     

OIL POINT PRESSURE OF SOYBEAN

The effects of processing conditions such as preheating moisture content (6, 8.3, 10 and 12%‐wet basis), heating temperature (70, 85, 100 and 115C) and heating time (15, 20, 25 and 30 min) on the oil point pressure of soybean seed was investigated. It was observed that increase in preheating moisture content from 6.0% to 12.0% (wet basis) increases the oil point pressure. The oil point pressure was found to decrease with increase in temperature and heating time from 70C to 115Cand 15 min to 30 min, respectively. It was also observed that increase in the moisture content during expression (postheating moisture content) from 2.6 to 11.6% increases the oil point pressure and the relationship can adequately be represented by a linear model. The postheating moisture content is affected by the initial moisture content, the heating temperature and heating time; therefore these factors affect the oil point pressure. The oil point pressure values obtained in the study were between 10.4 MPa (for sample at a moisture content of 6.0% heated at 115Cfor 30 min) and 17.2 MPa (for sample at a moisture content of 12.0% heated at 70C for 15 min).     

Simulation of migration from internal can coatings

Migration from can-coatings into retorted canned food simulants (canned oil and water, 121 degrees C, 30 min) was investigated through HPLC with a fluorescence detector and evaporative light scattering detector, and by measurements of residue on evaporation and consumption of potassium permanganate. HPLC analysis revealed that migration into the canned oil was hundreds of times more than that into n-heptane (25 degrees C, 60 min, the official test conditions according to the Japanese Food Sanitation Law), whereas it was similar to the migration into isooctane-butyl acetate mixtures (60 degrees C, 60 min), and that migration into the canned water was several times more than that into water (95 degrees C, 30 min, the official test conditions). Residue on evaporation for the n-heptane extract was several-fold lower than 30 ppm (the official limit), whereas that for the isooctane-butyl acetate mixtures exceeded 30 ppm. Consumption of potassium permanganate for the canned water was 30 times higher than that for the water extract (95 degrees C, 30 min). The official test conditions for can-coatings, in particular the use of n-heptane as an oil simulant, were suggested to lead to substantial underestimation of migration into canned food.