午餐肉罐头硫化黑变与容器材料选择的探讨

分析了午餐肉罐头硫化黑变的机理 ,围绕如何防止内容物与罐头内壁金属的反应 ,采用马口铁表面含铬量、镀锡量和涂料三因素三水平进行正交试验 ,样品经装罐、杀菌、保温2～ 180d后开罐评价硫化斑及硫化铁生成情况 ,通过正交试验数据分析 ,探讨对午餐肉罐头容器材料的选择     

午餐肉罐头粘罐原因和防止措施

午餐肉罐头开罐后常常出现内容物与罐身内壁及底盖相粘结、不易倒出的现象,此现象称之为粘罐。粘罐严重影响了午餐肉的商品价值,必须加以防止。产生午餐肉罐头粘罐的原因目前已基本清楚。本文结合生产实际谈几点看法并提出防止措施。 一 粘罐的原因 午餐肉罐头的主要原料是猪肉和淀粉。淀粉起填充剂和增稠剂的作用。猪肉的蛋白质中含有胶原蛋白,胶原蛋白在加热杀菌过     

猪蹄姜醋罐头杀菌工艺的优化

采用二次回归通用旋转组合设计进行试验,以杀菌效果和产品感官质量的综合评分为评价指标,优化猪蹄姜醋罐头热力杀菌的工艺并建立了杀菌数学模型。得到猪蹄姜醋罐头杀菌的最佳工艺参数:pH值4.3。封罐时罐头中心温度71℃、杀菌温度112℃、杀菌时间35min。     

热杀菌条件对金枪鱼罐头品质的影响

通过对185 g盐水浸金枪鱼罐头进行热穿透测试,以罐中心点致死率0F=8 min为目标获得110℃、116℃、119℃、121℃、124℃和127℃下的热穿透参数。得出随着杀菌温度的提高,杀菌时间可以显著减少(P0.05)。相对与110℃杀菌,采用116℃、119℃、121℃、124℃和127℃,杀菌时间可以分别减少58.94%、60.98%、71.14%、74.19%和78.46%。相同致死率下,采用较高温度杀菌可以显著减少C值(cook value)和C/F0值(P0.01)。L*值随杀菌温度的提高逐渐上升(P0.01),110℃时为58.76,127℃时为71.30。a*和b*值则呈下降趋势。硬度随杀菌温度的提高而增大(P0.05),110℃时为472.57g,127℃最大为796.03 g。挥发性盐基氮(TVB-N)值随杀菌温度的提高而减小(P0.05),110℃时为25.56 mg/kg样品,127℃时则为15.63 mg/kg样品。硫代巴比妥酸(TBA)值受杀菌温度影响显著(P0.05),在110℃最小为0.92 mg MDA/kg样品,127℃时最大为2.26 mg MDA/kg样品,反映了实验条件下,采用相对较高温度杀菌可以相对提高金枪鱼罐头的品质。     

鲣鱼罐头的变温与恒温杀菌工艺比较

基于F0=20 min的恒温杀菌工艺,本研究提出2 种具有相同F0值的不同变温杀菌工艺,并与恒温杀菌工艺进行比较。对杀菌锅和罐头冷点的温度变化进行实时监测,并记录温度变化曲线用于分析。结果显示,不同杀菌工艺具有不同的温度、时间组合和相同的F0值。较优变温杀菌工艺（105 ℃-115 ℃-120 ℃-125 ℃,每阶段持续2.5 min）与恒温杀菌工艺相比,罐头样品中鱼肉的硬度提升22.8%、弹性提升6.9%、内聚性提升20.5%;罐头样品中汤汁的浊度下降29.41%、粗蛋白含量下降48.13%;罐头样品的挥发性盐基氮值下降了20.14%。肌肉横切面扫描电子显微镜结果显示,变温杀菌工艺对鱼肉组织结构的破坏程度更小。由此可见,采用变温杀菌工艺可以减少鲣鱼罐头因杀菌造成的品质降低。     

罐头蒸汽杀菌循环冷却时间计算

基于罐头冷却内循环的新工艺,通过分析罐头杀菌冷却的传热方式及影响传热速率的因素,通过传热过程的数学描述,从而建立数值法计算方法和步骤。本文针对热传导型罐头食品进行理论计算和实验测量,以午餐肉罐头为例,计算得出午餐肉罐头准确的杀菌循环冷却时间。     

罐头杀菌冷点温度和F值测定系统的设计

在罐藏食品工业中,测定罐头冷点温度和计算杀菌F值一直是一个非常重要的问题。本设计以比奇洛杀菌理论为数学模型,开发了一套基于PC机的可编程开环数据采集系统对罐头的冷点温度进行连续采集并计算出杀菌过程中累计的F值,供在线监视或作为制定生产工艺的参考数据。系统硬件由温度传感器、数据采集仪、PC机、专用安装附件组成。温度传感器的探头被固定在冷点位置上,由数据采集仪通过RS-232串行通信方式将信号传给PC机做进一步处理。PC机的应用程序采用LabVIEW编写。该装置具备数据接收、F值计算、实时曲线绘制和数据保存的功能。实罐试验取得的测试数据表明整套系统可用来有效地演示或在线监视罐头食品杀菌过程中的温度变化。     

酱汁鲍鱼硬罐头杀菌工艺及流变学性质研究

目的：确定酱汁鲍鱼硬罐头最佳杀菌工艺,以保证产品安全性及最大限度地保留其营养价值,并进一步描述产品流变特性,为其质量客观评价提供一定的理论依据。方法：通过考察不同杀菌条件(不同F值)对罐头主要品质指标的影响确定最佳杀菌工艺;通过应力松弛试验测定鲍鱼流变特性;通过静态及动态流变试验测定酱汁流变特性。结果：不同杀菌条件对罐头主要品质指标产生明显影响,罐头最佳杀菌工艺为12min-12min-12min/121℃(F121.1℃=3.6min);鲍鱼流变(应力松弛)特性可用二元Maxwell模型很好的描述;酱汁属于非牛顿流体,显示出一定的黏弹性及弱凝胶性质,其流变特性可用Cross方程很好的描述。结论：以F值为指导所确定的罐头最佳杀菌工艺能保证产品安全性并最大限度地保留其营养价值;所描述的产品流变特性可为其质量客观评价提供一定的理论依据。     

基于COMSOL Multiphysics的金枪鱼罐头热杀菌过程数值模拟

以COMSOL Multiphysics软件为基础,建立纯传导和固液混合两种模型来模拟金枪鱼罐头的热杀菌过程。通过无线温度传感器检测热杀菌过程中130 g金枪鱼与55 g,4%Na Cl卤水罐头中心温度的变化,结果发现:固液混合模型的预测结果与试验数据十分吻合,而纯传导模型明显低估了罐内温度传递。在此基础上,用固液混合模型模拟工业杀菌条件(10 min-60 min-10 min/116℃)下金枪鱼罐头内的温度分布、速度分布及致死率值,结果发现最慢加热区(SHZ)位于罐高的22.9%~50%之间,最慢冷却区(SCZ)位于罐高的50%~81%处。在升温和降温阶段,罐内液体流速可达4.41 mm/s。杀菌结束时罐内最大与最小致死率值相差4.93 min,而中心点致死率与最小致死率相差很小。本文建立的模型可为金枪鱼罐头的热杀菌优化提供参考。     

罐头杀菌泠点温度和F值测定系统的设计

在罐藏食品工业中，测定罐头冷点温度和计算杀菌F值一直是一个非常重要的问题。本设计以比奇洛杀菌理论为数学模型，开发了一套基于PC机的可编程开环数据采集系统对罐头的冷点温度进行连续采集并计算出杀菌过程中累计的F值，供在线监视或作为制定生产工艺的参考数据。系统硬件由温度传感器、数据采集仪、PC机、专用安装附件组成。温度传感器的探头被固定在冷点位置上，由数据采集仪通过RS-232串行通信方式将信号传给PC机做进一步处理。PC机的应用程序采用LabVIEW编写。该装置具备数据接收、F值计算、实时曲线绘制和数据保存的功能。实罐试验取得的测试数据表明整套系统可用来有效地演示或在线监视罐头食品杀菌过程中的温度变化。     

Changes in free amino acids content in albacore (Thunnus alalunga) muscle during thermal processing

The effects of cooking and sterilization at several temperatures on the free amino acids (FAA) content in albacore (Thunnus alalunga) muscle were studied during the processing of canned tuna. FAAs were derivatized with o-phthalaldehyde, separated on a C18 column by HPLC and detected by both fluorescence and ultra-violet detectors. After cooking the loss of FAAs was not significant. However, in the final product sterilized at 115 degrees C and 110 degrees C (throughout the whole process) there were significant losses with regard to the start material, but not at 118 degrees C (all temperatures leading to the same lethal F-value). The influence of the thermal process time at 115 degrees C was evaluated for 60 and 100 min. Significant losses were found between both canned products (approximately 25%) and between the raw fish and the final product (approximately 12% and approximately 34%, process time 60 and 100 min, respectively). The determination of the content of FAA present in canned albacore may be a useful indication of the severity of the thermal processing.     

Determination of a process time for a new product: canned low acid artichoke hearts

In order to obtain a process time for canned low acid artichoke hearts, the heat resistance of Clostridium sporogenes PA 3679 in phosphate buffer (pH 7) and in artichoke puree (pH 5.2) was determined in the range of 100–118°C. D _T values in artichoke puree were determined by the most probable number and plate count methods. D _121°C values were deduced by extrapolation of the curves. An F 8.3/121 (see nomenclature section) target value of 1.8 min, equivalent to an F ₀= 2.5 min, was established considering a D _121°C value of 0.36 min for artichoke puree. The cold point for canned artichoke hearts in 1/2 kg (71.5x117 mm) cans was determined, a set of heat penetration and cooling curves were obtained and the values of the parameters ' j ' and ' f ' were found. A process time was deduced, 21.5 and 23 min of heating at 121°C, following the methods of Patashnik (1954) and Hayakawa (1970, 1974) respectively, in order to reach the F ₀ target of 2.5 min for this new canned food. This process was adequate, as the inoculated experimental pack test showed no altered cans out of 50 inoculated after 21.5 min of heating at 121°C.     

Contents of water-soluble vitamins in canned fish and seafood

Data of contents of vitamins (B1 and B2, C, PP) in production from gidrobionts is given. Is established, that the process of sterilization of canned food from gidrobionts in to container provides significant (almost twofold) decrease (reduction) of vitamins B1 [symbol: see text] B2, smaller losses of vitamin C (less than 30%) and proves to be true sufficient stability (almost on 85-90%) to action of high temperatures (120 degrees C) of vitamin PP. The canned food from sea gidrobionts represent the certain interest basically as a source of vitamin PP, and canned food "Herring smoked in oil"--vitamin B2. The canned food "Skobljanka from cucumber and fish" can be considered as a source of vitamins B2, C, PP.     

Thermophilic aerobic and facultatively anaerobic bacteria as causative agents of acidification of crab preserves

The authors studied the influence of regimen of canned crab sterilization on the viability of thermophilic aerobic and facultatively anaerobic bacteria in the product. It has been established that sterilization of canned crabs reduces contamination of the product with thermostable bacteria, although it does not ensure their complete death. During storage at a temperature of 8-10 degrees C thermophilic bacteria lose their capacity for acidification. The product can turn sour in the presence of these bacteria among the residual flora only during storage at higher temperatures.     

Effect of polythene film activated with enterocin EJ97 in combination with EDTA against Bacillus coagulans

Polythene films coated with the enterococcal bacteriocin enterocin EJ97 alone or in combination with EDTA were tested against Bacillus coagulans CECT 12. Bacteriocin activity was clearly enhanced by EDTA, as shown by viable staining and epifluorescence microscopy observation of treated cells. Activated films were tested in liquids from canned corn and canned peas inoculated with B. coagulans cell suspensions and stored at 4 °C and 20 °C for 24 h. The bacteriocin alone showed highest activity in samples stored at 4 °C, while the maximum performance of EDTA was observed at 20 °C. Films activated with a combination of both antimicrobials showed highest bactericidal activity at 4 °C. In liquid from canned corn and peas stored at 4 °C, the combined treatment reduced the concentrations of viable cells progressively over incubation time. Viable staining revealed an increase in the percentage of dead cells at 20 °C, avoiding proliferation of the bacilli. The bactericidal effect of the combined antimicrobial agents was higher in the liquid of canned peas than that of canned corn. The combined use of viable staining and classical viable cell counts allowed a better estimation of cell damage caused by the antimicrobial treatments.     

Effect of citric acid and citrate on the shelf stability of canned liver paste processed at reduced F(0) values

Citric acid and the combination of citric acid and citrate, in a few cases enriched with potassium sorbate, were tested for their stabilizing effect in a canned liver paste processed at reduced F(0) values. pH values of the rest products ranged from 5·24 to 5·76; a(w) values varied from 0·950 to 0·972. F(0) values of 0·05, 0·30 and 0·85 were applied. Before sterilization, the paste doughs were contaminated with mixtures of bacterial spores. Heated packages were challenged by incubation at 30 and 55°C for up to about 2 years. Incubated packages with the standard formulation at an F(0) of 0·05 showed the first blown cans at 30°C after 24 days. Starting from this point, at this F(0) value products with a variable, but increased, bacteriological stability were observed. At an F(0) of 0·30 a perfectly stable product at 30°C was observed after addition of 0·14% w/w citric acid only (product pH 5·69). Moreover, all tested combinations of additives at F(0) values of 0·30 and 0·85 yielded stable products at this incubation temperature. At the higher F(0) value a clear effect with respect to delaying thermophilic spoilage was observed. The effect of the application of potassium sorbate-in combination with both other additives-at F(0) values of 0·30 and 0·85 proved to be negligible.     

Changes in free amino acids content in albacore (Thunnus alalunga) muscle during thermal processing

Summary The effects of cooking and sterilization at several temperatures on the free amino acids (FAA) content in albacore (Thunnus alalunga) muscle were studied during the processing of canned tuna. FAAs were derivatized witho-phtalaldehyde, separated on a C18 column by HPLC and detected by both fluorescence and ultra-violet detectors. After cooking the loss of FAAs was not significant. However, in the final product sterilized at 115 °C and 110 °C (throughout the whole process) there were significant losses with regard to the start material, but not at 118 °C (all temperatures leading to the same lethal F-value). The influence of the thermal process time at 115 °C was evaluated for 60 and 100 min. Significant losses were found between both canned products (25%) and between the raw fish and the final product (12% and 34%, process time 60 and 100 min, respectively). The determination of the content of FAA present in canned albacore may be a useful indication of the severity of the thermal processing.

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Veränderung im Gehalt an freien Aminosäuren in Thunfischmuskel (Tunnus alalunga) während der Wärmebehandlung

Zusammenfassung Die Wirkung des Kochens und Sterilisierens bei verschiedenen Temperaturen auf den Gehalt an freien Aminosäuren (FAA) im Thunfischmuskel (Thunnus alalunga) wurde während der Herstellung von Thunfischkonserven untersucht. Die freien Aminosäuren wurden mito-Phtalaldehyd derivatisiert, auf einer C-18-Kolonne mit HPLC abgetrennt und durch Fluorescenz und UV-Detektoren nachgewiesen. Nach dem Kochen war der Verlust an FAA nicht signifikant, jedoch in dem bei 110° und 115 °C sterilisierten Endprodukt ergaben sich signifikante Verluste bezogen auf das Ausgangsmaterial, aber nicht auf das bei 118 °C erhitzte; alle Erhitzungstemperaturen führen zu demselben letalen F-Wert. Der Zeiteinfluß der Erhitzung bei 115 °C wurde bei 60 und 100 min bewertet. Signifikante Verluste sind bei beiden Dosenkonserven aufgetreten (25%) und zwischen diesen und dem Rohfisch ( 12% und 34%) bei einer Erhitzungszeit von 60 und 100 min). Die Bestimmung des FAA-Gehalts in Thunfischkonserven kann für den Nachweis der Einwandfreiheit des thermischen Prozesses sehr nützlich sein.

     

浅析HACCP在罐装凉茶生产中的应用

目的研究HACCP在以本草植物为原料生产出的罐装凉茶中的应用,确保凉茶的食品安全。方法基于HACCP体系的基本原理,对广东某著名凉茶企业进行实地调查,以罐装凉茶为研究对象,对罐装凉茶的整个生产过程制定危害评价程序,确定关键控制点,并采用相应的控制措施。结果将HACCP体系应用到罐装凉茶生产的各个环节中,本草原料验收,过滤,封口和杀菌这4个关键控制点最为重要。结论本研究建立的HACCP体系能够有效预防和控制凉茶生产过程中的食品安全问题。     

Modeling inactivation of Clostridium botulinum and vitamin destruction of non-Newtonian liquid-solid food mixtures by convective sterilization in cans

Unsteady fluid mechanics and convective heat transfer in the sterilization of canned tuna chunks immersed in a non-Newtonian fluid by a Darcy-Brinkmann-Forchheimer porous model has been studied numerically by a conjugate mathematical model. The coupled equations were solved by the Finite Volume method with the SIMPLE algorithm. The model developed related the sterilization time and temperature distribution with the kinetics of C. botulinum inactivation and the degradation of two relevant vitamins in canned tuna, riboflavin, and thiamin. Additionally, the effect of the covering liquid in the sterilization process and nutrients loss from canned tuna was investigated. The results showed that the sterilization time decreases in fluids with low viscosity, as water and brine, compared to CMC. The cases investigated had a different response to achieve complete sterility, considering the preservation of nutrients. Obtaining a balance between operating time and energy cost allows improving the process to make it more efficient.Industrial relevanceModeling of bacteria inactivation and vitamin degradation in liquid-solid food mixtures is of great interest because the extended number of relevant food processes involve heat transfer in these matrices, where is mandatory an accurate estimation of time and conditions essential for a complete sterilization process.     

即食梅香黄鱼热杀菌过程中的品质变化

为研究软包装即食梅香黄鱼在热杀菌过程中的品质变化,比较不同杀菌温度时间组合、不同喷淋水升降温速率在一定温度下杀死90%的微生物所需要的时间(F值)、热加工过程中导致食品外观特性变化的热损失值(C值)和品质指标(色泽、质构、汁液流失率)。结果表明：杀菌时间越长,F值增加越明显;杀菌温度越高,增加单位时间所带来的F值、C值的增加越明显;喷淋水升降温速率快慢相比,在达到相同F值时,所需的杀菌恒温时间是前者大于后者,前者表面C值更大,两者中心C值接近,前者C/F值也更大;高温短时杀菌色泽、质构好、汁液流失率少;喷淋水升降温速率快,汁液流失率少。在实验范围内适宜的杀菌条件为：127℃、升温速率fh＝10.99min,降温速率fc ＝12.32min。