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.     

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.     

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.     

A Rapid Gas Chromatographic Method for the Identification of Sporeformers and Nonsporeformers in Swollen Cans of Low-Acid Foods

A rapid gas-liquid chromatographic method for the identification of sporeformers and nonsporeformers as the probable cause of swollen cans of low-acid foods was developed and evaluated. Cans of five types of food were inoculated with cultures of seven sporeforming organisms and three nonsporeformers. The supernatant from the can content was assayed on two packed columns designed for the assay of aqueous solutions of volatile free acids using flame ionization detectors. A statistical discriminant analysis was conducted on selected peak areas. Overall, 88% of 120 cans were correctly identified in the standard data set and 80% of 110 cans analyzed as unknowns. Sporeformers were detected in 62% of 30 cans inoculated with three mixtures of sporeformers and nonsporeformers.     

Can Material Influence on the Performance of Rotating Cookers

The rotational performance of ETP (electro-tin-plated) and TFS (tin-free-steel) cans was studied in pilot and commercial cookers, and in a cooker simulator. TFS cans rotated less than ETP cans in both commercial and pilot cookers. Commercial cookers showed less can rotations than corresponding pilot scale experiments. The simulator predicted an exponential decay in lethality with decreased can rpm. Polymer coated cans conditioned the cooker surface and the extent depended on contact time. Heat transfer depended on can rotation and could be predicted with a suitable correlation. The correlation was used to predict lethality performance as well as exit temperature of processed foods.     

Review: Flame sterilization

Flame sterilization is a technique of high temperature, short time processing that is applied to sealed metal cans. The technique is applicable to the processing of both high and low acid products and may be used to exhaust packs to produce a high vacuum when subsequently cooled. The factors affecting the rate of heat transfer and their influence on container requirements and product quality are discussed, together with commercial developments and prospects for flame sterilization processes.     

Storage stability of a high protein food beverage powder prepared from the Nigerian ‘red skin’ groundnut (Arachis hypogaea) protein concentrates

A high protein, groundnut-based powder reconstitutable into a milk-like beverage was packed in polyethylene bags and in lacquered tin cans, and stored at both room temperature (25 ± 2°C) and in a domestic refrigerator (5 ± 2°C) for 60 days. Storage stability was evaluated by analysing periodically for changes in physical characteristics, proximate composition, and development of browning and rancidity, and assessing moisture sorption characteristics. Protein, lipid, total soluble sugars, peroxide value, total carbonyls and extinction values of the ethanolic extract remained practically constant during storage. The isotherm curves exhibited the characteristic sigmoidal shape typical of high protein foods. There was a greater increase in density, hygroscopicity and wettability in polyethylene-packed samples at both temperatures suggesting that the lacquered tin can leads to better keeping quality for this product.     

应用于锡罐封盖的可撕式盖膜

<正> 约在150年前,生产商首次利用锡罐来包装食品。自此,人们便不断改进这种包装的形式,从而发展使用方便的封罐方式。加拿大包装公司Lawson Mardon Singen GmbH,提供可撕式封罐膜材料Alufix,这种材料曾获多个国内及国际奖项。     

Storage Changes of Fresh and Pasteurized Blue Crab Meat in Different Types of Packaging

We investigated pasteurization and storage of blue crabmeat in steel cans, aluminum cans, plastic cans, nonbarrier pouches, and barrier pouches. Fresh meat was packed in copolymer polyethylene/polypro-pylene cups, Saran® over-wrapped or vacuum skin packaged polystyrene trays, and nonbarrier pouches. Meat pasteurized in plastic and aluminum cans had better sensory and microbiological quality and longer shelf life than meat packed in steel cans. Oxygen-barrier pouches had the lowest quality and shortest shelf life. Nonbarrier pouches had product with quality similar to meat in steel cans, but with an extended shelf life. No packaging materials improved the microbiological shelf life of freshly cooked meat. Vacuum skin packaging resulted in improved sensory qualities of freshly cooked and picked meat.     

Can Fitting in Green Beans: Effect of Growing Season, Base Steel Composition, Tinplate Thickness, Can Vacuum and Storage Conditions

Spring and fall grown green beans were packed under high and low vacuum conditions in high and low residual Al, Ni, Cu, Si, S, and Mn base steel .25 and .50 electrotin plated J-enamel cans and evaluated during storage at 38°C and room temperature for pitting on and under the s deseams. Cans containing spring grown beans were more severely pitted than those of the fall pack. High residual (0.061%) Cu steel cans were more severely pitted than other treatments. The .25 electrotin plated cans were more severely pitted in high Cu residual cans, as were the low vacuum spring pack cans at 38°C storage.     

Corrosion Characteristics of Soldered Sideseam Tinplate and Welded Sideseam ECCS Plate Cans Using Organic Acid Model Systems

A model system of six organic acids and water was prepared using two pH ranges and two nitrate levels and packed in soldered sideseam tinplate and welded sideseam enameled cans. Can vacuum, Fe and Pb content were determined after 8-months storage at room temperature and at 38°C. The ECCS plate cans had lower can vacuums and lower solution Fe content than the tinplate cans. Polygalacturonic acid (PGA) was an aggressive corrosive agent in both can types. Water, PGA and malic acid solutions contained the highest concentrations of Pb.     

THE AROMA OF CANNED BEEF: PROCESSING AND FORMULATION ASPECTS

The influence of processing techniques and formulations on chemical and sensory aroma properties has been studied with the purpose of finding ways to improve the flavor of canned meat. HTST-sterilization, "aseptic" canning and sterilization in various packaging materials including flexible pouches have been investigated. It was found that "aseptic" canning and, especially, HTST-sterilization had a pronounced positive effect on aroma, in the latter case for samples packed in thin layers (flexible pouches). It was shown that addition of e.g., fumarate or maleate in small amounts (0.06–0.15%) before sterilization decreased the concentrations of hydrogen sulfide and mercaptans, and the additions of certain amino acids, e.g., arginine, decreased the concentrations of the aldehydes. Both types of ingredients resulted in an improved aroma. Storage changes have also been investigated. It was found that there was a tendency towards a more accelerated change in flexible pouches compared with rigid cans.     

食品金属罐中14种双酚类物质迁移量的同时测定及杀菌过程对其迁移的影响

为了调查国内食品金属罐中双酚类物质的迁移水平,本文建立了同时测定食品金属罐中14种双酚类物质迁移量的高效液相色谱法,并研究了杀菌过程对双酚类物质迁移的影响及食品金属罐中双酚类物质的迁移规律.结果表明,14种双酚类物质在4种食品模拟物(4％体积乙酸、10％体积乙醇、50％体积乙醇和异辛烷)中线性关系良好,加标回收率为83...     

Linear Model for Predicting Transient Temperature during Sterilization of a Food Product

The thermal behavior of a conductive canned food during retorting was represented using an input-output linear system, with a finite order N, and a time-delay. The input of the system was the retort temperature, the output was the temperature at the thermal center of the can. This model was applied for a typical sterilization process composed of two isothermal steps. The can internal temperature was expressed as a sum of N exponential terms in which appeared the constant holding retort temperatures, the come-up and come-down times and N pairs of heat penetration parameters identified in a preliminary experiment. The model was tested on a potato mash packed in metal cans processed in a vertical still retort. Temperatures estimated by the model agreed closely with those measured during thermal processing.     

食用菌罐头商业无菌BacT/ALERT3D系统快速检测方法的研究

目的:探索和研究一种快速的罐头商业无菌检验方法。方法:对BacT/ALERT 3D系统在罐头商业无菌检验中的特异性、灵敏度和适用性进行评估,建立了罐头商业无菌仪器检验方法并与传统罐头商业无菌检验方法进行比较。结果:表明该方法检测结果可靠,简便、快速、灵敏,全部检测过程可在3d内完成。结论:BacT/ALERT 3D微生物检测系统适用于食用菌罐头商业无菌的检测。     

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。     

Lead, chromium, tin, iron and cadmium in foods in welded cans

The levels of lead, chromium, tin, iron and cadmium in fruit and vegetables in welded tinplate cans were determined by atomic absorption spectrophotometry. The levels found were compared with those in foods in soldered tinplate cans and fresh foods. The results show that the lead levels in foods in welded cans were much lower than those in similar foods in soldered cans. Foods in unlacquered welded cans contain much more lead, chromium and tin than foods in lacquered welded cans. The cadmium and iron levels in canned fruit and vegetables in welded cans were similar to those found in the corresponding fresh foods.     

THE TBA METHOD AS AN INDEX OF OXIDATION OF THERMALLY PRESERVED TURKEY MEAT IN PLASTIC TRAYS AND CANS

Thiobarbituric acid (TBA) determinations of malondialdehyde (MDA) in thermally preserved red turkey meat packed in high barrier plastic trays and in cans, were carried out as a function of product layer and storage temperature (15, 25 and 35C). Several types of plastic trays, with different oxygen permeabilities, were evaluated. In the most permeable plastic trays the product in the surface layer reached maximum TBA values at all storage temperatures after a certain storage period, followed by their decrease. In the higher barrier trays and in the cans, the TBA values decreased continuously with time. The peak TBA values, observed in the least barrier plastic trays declined with storage temperature. In the inner product layers, the TBA values decreased during storage in all types of packages and at all temperatures. The reduction in TBA values can be explained by the disappearance of TBA reacting substances (TBARS). The extent of TBARS disappearance was greater in the absence of oxygen than in its presence. The results of this study indicate that TBA determinations are not a reliable indicator for quality deterioration during storage of thermally treated meat products in plastic packages.     

基于Fluent的黄桃罐头杀菌过程数值模拟及其形状优化

探究食品罐头杀菌作业中的升温过程,研究现有罐头包装尺寸变化对提升杀菌效率及节能降耗的影响程度。使用ANSYS Fluent软件进行流场及温度场进行仿真分析,通过试验验证模拟的可靠性。在此基础上改进黄桃罐头的瓶体形状,提升杀菌效率。结果表明:试验结果与模拟结果升温趋势一致,最大误差为3.5°。罐头底部直径大小与罐内最高流速呈负相关,150 s时,罐头底部直径越小,罐内液体最高流速越高。相同高度与容积条件下,缩小底部直径可以提高杀菌效率,底部直径为52.5 mm的罐头杀菌效果最好,与圆柱罐头相比效率提升10.26%。通过ANSYS Fluent可以准确模拟食品罐头在杀菌过程中的温度场变化。