Tin and Iron Content of Canned and Bottled Foods

The tin and iron content of 14 different types of canned foods and of 5 different types of bottled foods were determined. No tin was detected in most bottled foods, but tin was detected in all canned foods. Storage of foods on the shelf for 4 months or in open cans in the refrigerator for 1 wk resulted in increased amounts of tin and iron in some of the canned foods. Those foods which were packed in totally lacquered cans accumulated little tin or iron during storage; those foods which were packed in unlacquered or partially lacquered cans generally accumulated significant amounts of iron and tin during storage. The tin content of the canned foods was not statistically correlated to the pH of the foods.     

Aluminium content of beers

 The aluminium (Al) concentration in different brands of beers packaged in Al cans and glass bottles was measured at the end of the shelf-life of the beer, by the Zeeman graphite furnace atomic absorption spectrophotometry (ZGFAAS) method. The results show that in all cases a brand of beer packaged in an Al can has a higher Al content than the same brand bottled in glass. The measurements of the Al concentration in some Al-canned beers throughout 12 months of storage show that a relatively small increase of the Al concentration in beers occurs throughout storage. All these results indicate that some Al is taken up by the beer in Al cans, presumably through the slight and slow dissolution of Al from the can wall, due to some defects in the protective lacquer layer. The evaluated daily intake of Al (0.256 mg) possible through the consumption of beer was practically negligible in relation to both the total daily dietary Al intake and the tolerable daily Al intake. Thus, beers are an insignificant source of dietary Al intake and it appears that the Al intake from beers (due to the low content of Al in beers and its low bioavailability) should not be a cause for concern with regard to Al toxicity for the human body. Received: 22 April 1996     

Aluminium content of beers

 The aluminium (Al) concentration in different brands of beers packaged in Al cans and glass bottles was measured at the end of the shelf-life of the beer, by the Zeeman graphite furnace atomic absorption spectrophotometry (ZGFAAS) method. The results show that in all cases a brand of beer packaged in an Al can has a higher Al content than the same brand bottled in glass. The measurements of the Al concentration in some Al-canned beers throughout 12 months of storage show that a relatively small increase of the Al concentration in beers occurs throughout storage. All these results indicate that some Al is taken up by the beer in Al cans, presumably through the slight and slow dissolution of Al from the can wall, due to some defects in the protective lacquer layer. The evaluated daily intake of Al (0.256 mg) possible through the consumption of beer was practically negligible in relation to both the total daily dietary Al intake and the tolerable daily Al intake. Thus, beers are an insignificant source of dietary Al intake and it appears that the Al intake from beers (due to the low content of Al in beers and its low bioavailability) should not be a cause for concern with regard to Al toxicity for the human body. Received: 22 April 1996     

Changes in individual carotenoids on processing and storage of mango (Mangifera indica) slices and purée

Susceptibility of different carotenoids to degradation during thermal processing and storage of two mango cultivars was investigated. The carotenoid composition was practically maintained on processing mango (cultivar Tommy Atkins) slices. The only significant change was the increase in luteoxanthin, compatible with the conversion of 5,6- to 5,8-epoxide. More evident transformations occurred on processing mango (cultivar Golden) purée. The major pigment β-carotene decreased 13%, resulting in a corresponding reduction of the vitamin A value. Auroxanthin, not found in the fresh fruit, appeared while violaxanthin and luteoxanthin decreased. During storage of mango slices in lacquered (epoxy) or plain tin-plate cans, no appreciable loss of β-carotene was observed during 10 months. Between the tenth and fourteenth month, about 50% reduction of β-carotene occurred. The degradation continued, resulting in a total loss of 84% after 24 months. A tendency of violaxanthin to decrease, and auroxanthin to increase, during storage was also noted. β-carotene showed a greater susceptibility to degrade in bottled mango purée (18% loss after 10 months) than in the canned product. As in the case of mango slices, however, both bottled and canned purée suffered 50% loss of β-carotene after the tenth month, and a total loss of 83% after 24 months. Violaxanthin and luteoxanthin tended to decrease while auroxanthin maintained a comparatively high level throughout storage. The vitamin A values reflected the degradation trend of β-carotene, a pattern that appears to agree with a free radical mechanism.     

国产柑橘罐头感官品质和营养成分分析

目的建立国产柑橘罐头加工品质档案,为企业生产及消费者挑选更优质的柑橘罐头提供参考。方法通过苯酚-硫酸法、3,5-二硝基水杨酸比色法、比色法、分光光度法等对国产柑橘罐头感官品质和营养成分进行分析。结果马口铁的柑橘罐头较玻璃瓶和软包装Vc和黄酮含量高;浙江省产柑橘罐头不完整瓣数比例低,为5.02%,总糖含量较高;河北省产柑橘罐头Vc和类胡萝卜素含量高,分别为43.70、20.78 mg/100 g;包装容量为300～400g的柑橘罐头不完整瓣数比例较低,为10.33%,感官品质较佳;贮藏期较短柑橘罐头较贮藏期较长柑橘罐头可溶性固形物比例高,Vc、黄酮和类胡萝卜素含量高。结论马口铁柑橘罐头对易氧化营养成分的保存率优于玻璃瓶和高阻隔软包装。贮藏时间越短,柑橘罐头感官品质和营养成分损失越少。     

Corrosion behaviour of tinplate cans in contact with tomato purée and protective (inhibiting) substances

The dissolution of iron and tin from tinplate cans filled with tomato purée (pH 4.34) and dioctyl sebacate oil (DOS), essential onion oil (EOO) or potassium nitrate was studied using atomic absorption spectroscopy (AAS), while nitrate was determined using high-performance liquid chromatography (HPLC). The maximum values found in cans were up to 284 mg kg^?1 for tin and 513 mg kg^?1 for iron at elevated storage temperature. Results indicated that the addition of EOO to tomato purée prevents the corrosion process in the case of tin, where concentrations were lowered from 223 to 28 mg kg^?1 for cans with DOS oil and EOO at 20°C, respectively (inhibition rate of 87%). On the other hand, the presence of EOO enhanced the corrosion process for iron increasing the concentration from 15 to 46 mg kg^?1 during 7 months of storage, although this value did not exceed maximum permitted value (50 mg kg^?1). In cans with tomato purée and potassium nitrate, dissolution of tin started after 30 (36°C) and 60 (20°C) days of storage as a consequence of nitrate action, which act as a corrosion accelerator. Since the addition of EOO improves the taste of canned tomato purée, its potential use as a corrosion inhibitor would be of interest.     

Lead in alcoholic beverages

Following the finding that blood lead concentrations in middle-aged men were positively associated with alcohol consumption, the Royal Commission on Environmental Pollution recommended that information on lead in alcoholic beverages be obtained. The results reported here were obtained in response to the Royal Commission's request. About 90% of canned and bottled beers contained less than or equal to 10 micrograms/l of lead, whereas nearly half the draught beers sampled contained greater than 10 micrograms/l and 4% contained greater than 100 micrograms/l. Opening the cans and bottles and pouring the contents into a glass had no significant effect on the lead concentration in the beer. All wines sampled directly from the bottle, that is without pouring, contained less than 250 micrograms/l of lead. However the lead concentration in some wines contained in lead-capped bottles increased significantly when the wine was poured from the bottle, in one instance the increment was 1890 micrograms/l. It is concluded that consumption of beer containing 50 micrograms/l of lead could make a substantial contribution to blood lead concentrations in man. Consumption of 1 l/day of wine containing 150 micrograms/l of lead could also make a major contribution to blood lead concentrations. Lead contamination of wine when it is poured from a bottle, which had been lead-capped, can sometimes greatly increase lead concentrations in the wine.     

Sensory assessment of the shelf life of carbonated soft drinks

Six commercial soft drinks, in glass bottles and aluminium cans, were stored at 0.6°C and ambient temperature and assessed by a consumer-type sensory panel every 3 months for 2 years. While there was evidence of deterioration with storage, more so at ambient temperature than at 0.6°C, all drinks were still considered satisfactory at the conclusion of the trial.     

Analysis of fruit juice by atomic absorption spectrophotometry. I. The determination of iron and tin in canned juice

Atomic absorption spectrophotometry has been used to compare the concentrations of iron and tin in canned fruit juice with those in juice not stored in cans. No significant difference was found in the level of iron, but the amount of tin was considerably higher in canned samples. The determination is rapid, and no ashing procedure is required.     

马口铁包装水果罐头中锡的浓度变化和形态分布研究

目的 研究马口铁包装水果罐头中锡的浓度变化和形态分布。方法 采用电感耦合等离子体串联质谱法(inductively coupled plasma tandem mass spectrometry, ICP-MS/MS)测定马口铁包装水果罐头的锡含量,并分析锡浓度随储存时间、加热次数的变化特点;采用高效液相色谱电感耦合等离子体串联质谱法(high performance liquid chromatography-inductively coupled plasma tandem mass spectrometry, HPLC-ICP-MS/MS)测定并分析罐头中锡的形态分布。结果 镀锡马口铁包装水果罐头中锡含量在生产日期3个月内为27.17~183.81 mg/kg,生产日期12个月时为54.56~265.44 mg/kg,锡浓度随储存时间、加热次数而明显增加,溶出锡为无机形态,以二价锡Sn[II]为主,未检测到锡的有机形态。结论 马口铁包装水果罐头中锡随储存时间和加热次数而大量增加,但都以无机锡的形态存在,因吸收利用率低,毒性较低;尽量选择靠近生产日期的产品,且不要罐内加热食用。     

The role of corks in oxidative spoilage of white wines

The permeability of corks to oxygen was examined by comparing the level of browning and the concentration of the antioxidants, free and total sulfur dioxide and ascorbic and erythorbic acids in wines bottled and sealed with two cork types and stored in an atmosphere of either nitrogen, oxygen or air. Three different batches of corks that had been treated with peroxide during processing, representing one cork type, and a batch of corks that had been treated with chlorine during processing representing the second cork type, were taken for the study. In bottled wines stoppered with one of the peroxide-treated corks (Cork A), there was a higher level of browning and a greater loss of the antioxidants in those wines in bottles stored under oxygen and air than that in the wines in bottles stored under nitrogen, indicating that corks of this batch were permeable to oxygen. There was no significant difference in the loss of ascorbic and erythorbic acid or the level of browning from bottled wines stored under the three gases and sealed with the chlorine-treated corks (Cork C). For the other two peroxide-treated corks (Corks B and D), there was no significant difference in the level of browning or loss of the antioxidants from bottled wines stored under the three gases and sealed with Cork B, nor was there a significant difference in the level of browning or loss of free or total sulfur dioxide from bottled wines stored under the three gases and sealed with Cork D. From comparative data, it was evident that oxidation of the wines sealed with Corks B and D was due to compounds in the corks rather than oxygen permeation through the corks, or oxygen ingress at bottling. Because the bottles of wine selected for this study were from batches that had already exhibited sporadic oxidation, the results found are indicative, but not necessarily representative, of the properties of all peroxide- and chlorine-treated cork types used in the wine industry.     

肉类罐头食品中双酚A二缩水甘油醚及其衍生物的迁移

本实验应用高效液相色谱-电喷雾串联质谱法分析检测肉类罐头食品中双酚A二缩水甘油醚(BADGE)及其衍生物的残留,重点研究了肉类罐头中的内容物、存储时间(6个月、9个月、12个月)以及存储温度(4、20、100℃)对双酚A二缩水甘油醚(BADGE)及其衍生物的迁移量的影响,单因素方差分析(One-way ANOVA)检验实验结果表明,不同内容物罐头中从内壁涂层迁移至样品的BADGE及其衍生物存在显著性差异(p<0.05),Student-Newman-Keuls法检验表明存储12个月后目标化合物的迁移量与6个月、9个月存在显著性差异,存储温度为4、20℃时化合物迁移量没有显著差异,但是罐头加热到100℃后目标化合物迁移量是最大的。     

Aluminium in foodstuffs and diets in Sweden.

The levels of aluminium have been determined in a number of individual foodstuffs on the Swedish market and in 24 h duplicate diets collected by women living in the Stockholm area. The results show that the levels in most foods are very low and that the level in vegetables can vary by a factor 10. Beverages from aluminium cans were found to have aluminium levels not markedly different from those in glass bottles. Based on the results of the analysis of individual foods, the average Swedish daily diet was calculated to contain about 0.6 mg aluminium, whereas the mean content of the collected duplicate diets was 13 mg. A cake made from a mix containing aluminium phosphate in the baking soda was identified as the most important contributor of aluminium to the duplicate diets. Tea and aluminium utensils were estimated to increase the aluminium content of the diets by approximately 4 and 2 mg/day, respectively. The results also indicate that a considerable amount of aluminium must be introduced from other sources.     

Investigation of fish product–metal container interaction using scanning electron microscopy–X-ray microanalysis

Scanning electron microscopy (SEM) and X-ray microanalysis (EDS) were used to investigate metal can discoloration and lacquer adhesion failure in enameled food cans containing tuna in vegetable oil and octopus in brine, respectively. Black and brown spots on the internal surface of the can body were caused by the formation of FeS and SnS, respectively. The source of metal can discoloration was traced to inadequate lacquering of the tin plated steel, exposing both tin and iron to sulfur containing amino acids originating from the tuna product. Enamel adhesion failure in canned octopus was also traced to local defects in the lacquer coating enabling both NaCl and citric acid contained in the brine to cause enamel blisters on the can body leading to lacquer peeling and in turn to local detinning and steel corrosion. The first defect known as “sulfide staining” is harmless to human health and does not usually affect the product. The second defect may cause extensive detinning and steel corrosion possibly affecting the safety of the canned product. This postulation is supported by iron and tin concentrations both in the product and liquid medium carried out by atomic absorption spectroscopy.     

Iron and tin content of canned fruit juices and nectars

A survey of the iron and tin content of twelve different types of canned fruit juices and nectars revealed that, of the 122 cans examined, 23 (or 18·9%) contianed iron in excess of 15 mg kg^?1 and 16 (or 13·1%) contained tin in excess of 250 mg kg^?1. Apple juice and tomato juice were found to contain particularly high levels of iron, the maximum level recorded being 42·6 mg kg^?1. Mango juice and orange juice exhibited significant non-compliance with recommended Codex tolerance limits for tin. Statistical analysis showed that, at the 5% probability level, the mean iron contents of products packed in completely unlacquered and end-lacquered cans were not significantly different from each other, but were significantly lower than the mean iron content of products packed in fully lacquered cans. The mean tin content fell in the order unlacquered > end-lacquered > fully lacquered cans.     

Effect of Heat Processing on the Texture Profile of Canned and Retort Pouch Packed Oil Sardine (Sardinella longiceps) in Oil Medium

ABSTRACT: Sardine in oil was canned at 3 different Lethality values (F₀ 5,7, and 9) in retort pouches and aluminum cans in stationary retort. Process time calculations were done mathematically to find out the actual process time. Sardine in oil processed in retort pouches had a lower process time compared with aluminum cans for each F₀ value. Instrumental texture analysis was done using a food texture analyzer to study the effect of thermal processing on the texture of thermally processed sardine in oil in aluminum cans and retort pouches. As the F₀ value and cook value increased in both the retort pouches and aluminum cans, the textural properties showed a decreasing trend. Hardness of the product canned in both aluminum cans and retort pouches decreased with increase in F₀ values.     

COLOR OF PROCESSED SWEET POTATOES: EFFECTS OF CAN TYPE

Sweet potatoes packed in four types of enamel-lined cans were darker in color and less attractive than those packed in tin-coated cans. The differences in color among can types was more pronounced after opening the canned product and exposure to air for an hour. The tin content of the product from the tin-coated cans was much greater than that from the enamel-lined cans. The brighter color of the product from the tin-coated cans is assumed to result from the substitution of tin for iron or other metals in the complex formed in the pheno-lase reactions.     

Contamination of bottled waters with antimony leaching from polyethylene terephthalate (PET) increases upon storage

Antimony concentrations were determined in 132 brands of bottled water from 28 countries. Two of the brands were at or above the maximum allowable Sb concentration for drinking water in Japan (2 microg/L). Elevated concentrations of Sb in bottled waters are due mainly to the Sb2O3 used as the catalyst in the manufacture of polyethylene terephthalate (PET(E)). The leaching of Sb from PET(E) bottles shows variable reactivity. In 14 brands of bottled water from Canada, Sb concentrations increased on average 19% during 6 months storage at room temperature, but 48 brands of water from 11 European countries increased on average 90% under identical conditions. A mineral water from France in PET(E), purchased in Germany, yielded 725 ng/L when first tested, but 1510 ng/L when it was stored for 6 months at room temperature; the same brand of water, purchased in Hong Kong, yielded 1990 ng/L Sb. Pristine groundwater containing 1.7+/-0.4 ng/L Sb (n = 6) yielded 26.6+/-2.3 ng/L Sb (n = 3) after storage in PET(E) bottles from Canada for 6 months versus 281+/-38 ng/L Sb (n = 3) in PET(E) bottles from Germany. Tap water bottled commercially in PET(E) in December 2005 contained 450+/-56 ng/L Sb (n = 3) versus 70.3+/-0.3 ng/L Sb (n = 3) when sampled from a household faucet in the same village (Bammental, Germany), and 25.7+/-1.5 ng/L Sb (n = 3) from a local artesian flow.     

Effects of Acidified Processing and Storage on Proteins and Lipids in Mung Bean Sprouts

Fresh mung bean sprouts contained 5.3g protein/100g fresh weight which decreased slightly on blanching and on bottling and canning. Storage of bottled seedlings for 6 months at 35°C caused the largest loss in total protein. The protein contained the essential amino acids tryptophan, valine, leucine, phenylalanine, arginine, lysine and histidine. Total lipids of fresh mung bean sprouts were 350 mg/100g fresh weight and were not greatly affected by blanching nor by canning or bottling. When the bottled seedlings were stored at 10°C and at RT, the canned seedlings at RT, there was some effect on total lipids in that only bottled seedlings at 35°C showed a significant decrease in lipids. After storage at the three temperatures there were increases in glycolipids and decreases in phospholipids, due mainly to increases in monogalactosyldiglyceride and decreases in phosphatidic acid respectively.