Characterization of the flow behaviour of sausage emulsions with a simple tube viscometer

A specially designed tube viscometer was used to measure apparent viscosity during flow of Bologna type sausage emulsions moving through a pipe. Emulsions varied in fat content (from 21.8 to 44.3%) and in moisture/protein ratio (from 3.7 to 5.6), and the effects of added sodium chloride, sodium diphosphate, starch and blood plasma were investigated in a 36% fat, 3.7 moisture/protein emulsion.
The shear stresses determined as a function of shear rate were fitted by a power law. Yield stress of the emulsions was negligible relative to the applied stress. However, inspection of the flow profiles indicated that considerable slip of the sausage emulsion occurred at the pipe wall. Both emulsion flow and slip contribute to overall flow behaviour, so a kind of effective viscosity is determined. Intrinsic rheological properties and wall slip will both be affected by the composition of the sausage emulsion.     

European intercomparison on electron spin resonance identification of irradiated foodstuffs

The results of a co-trial organized by the Community Bureau of Reference on the use of Electron Spin Resonance spectroscopy for the identification of irradiated food in 21 laboratories are presented. The trial was qualitative on beef and trout bones, sardine scales, pistachio nut shells, dried grapes, and papaya, and quantitative on poultry bones. There was no difficulty in identifying irradiated meat bones, dried grapes, and papaya. In the case of fish bones there is a need for further kinetic study on different species. Identification of irradiation in pistachio nuts is more complicated and additional research is needed before further trials. All laboratories were able to distinguish between chicken bones irradiated at 1 to 3 kGy or 7 to 10 kGy although there was a partial overlap between the results.     

Conservation en congélation et réfrigération de la viande hachée de boeuf et de porc: évolution de la flore microbienne et des propriétés physico-chimiques en cours de stockage

The minced meat market in Belgium is growing steadily; its share of the market has increased from 10 to 30% in three years. However, the mincing of meat can produce intense microbiol proliferation and thus cause food putrification.Any changes occurring in meat, especially minced meat, are essentially of microbial origin, hence refrigeration is particularly important. With chilling, minimum temperatures must be maintained (0±1°C), since only temperatures below +3°C avoid any health risk linked with the growth of pathogens and production of toxins. Under chilled conditions the storage use of minced meat is four to five days. With freezing, temperatures of about - 18°C are needed to avoid the growth of bacteria, yeasts and mould. At this temperature micro-organisms are progressively rendered inactive, but destruction is never total. The kinetics of reducing micro-organism populations depends on the nature of the micro-organisms, the storage temperature (reduction is more intense at − 12°C that at − 18°C or at − 30°C) and the freezing rate (micro-organisms are better able to resist rapid freezing than slow freezing). One years storage at − 18°C will destroy 90 to 99% of the micro-organisms which were initially present in the product. Nevertheless, the chilled storage (+4°C) of thawed minced meat must not exceed three days.The physico-chemical evolution of cold stored minced meat is explained. In chilled storage, the onset of flavour defects can be related to the measurement of volatile nitrogen. In frozen storage, the crystallisation of the water causes cellular breakdown. The role of packaging is important in avoiding superficial freeze-drying which is accompanied by browning. In addition, fatty matter can deteriorate by oxidation even at freezing temperatures. The degree of alteration of fats can be appreciated by the acidity index and peroxide index (showing that it is undesirable to store minced pork at − 18°C for more than nine months).Use of a partial vacuum or modified atmosphere in combination with impermeable packaging will prolong the storage life of minced meat provided that the initial contamination is as low as possible and the maintenance of the cold chain is strictly respected.

Résumé

Le marché de la viande hachée progresse en Europe, du fait de plusieurs facteurs socio-économiques. Le hachage diminue considérablement la durée de conservation de la viande; sa consommation peut être dangereuse.L'article analyse les points suivants: emballage, réfrigération et congélation (notamment vitesse de congélation), température et durée de conservation, atmosphères modifiées et leur influence sur les propriétés physico-chimiques de la viande et sur le comportement microbien.     

火锅虾滑肠加工工艺研究

研究一种火锅虾滑肠的制作过程及工艺.通过单因素试验确定了影响火锅虾滑肠品质的主要因素及最佳水平范围.通过正交试验确定了主要影响因素的最佳配比:新鲜虾肉添加量为40％、金线鱼鱼糜添加量为14％、木薯变性淀粉添加量为2％、斩拌时间为6min,在此添加量及工艺条件下,生产出的产品经火锅水煮,结构及风味表现最佳.     

试论涪陵榨菜软实力的提升

涪陵榨菜属地理标志商标,是涪陵的重要软实力之一。认识涪陵榨菜的软实力,加大营销力度,提升涪陵榨菜的国际知名度,有利于推动涪陵榨菜健康与快速发展。文章从软实力的含义、涪陵榨菜硬实力和固有软实力的体现、提升涪陵榨菜软实力的途径与措施进行了论述。     

利用乳蛋白改善肉糜制品质量

乳蛋白是肉糜制品的优质乳化剂,它能与水和脂肪界面充分结合,形成较为稳定的水—蛋白质—脂肪系统,合理使用,可赋予成品良好的风味和口感及优良的物理性能.同时使用乳蛋白还可以尽量利用生产中的边角余料、低档肉,提高肉的利用率,降低生产成本.     

A laboratory evaluation of a novel hot water cabinet for the decontamination of sides of beef

A hot water cabinet based on an idealized distributor design for the decontamination of sides of beef is described and a laboratory evaluation of this novel cabinet is reported.
Beef sides were inoculated with E. coli and exposed to mean water temperatures at the surface tissue ( T _f) of 83.5, 74.2, 66.0 and 44.5°C for 10 or 20 s. Mean log₁₀ reductions of bacteria for 10-s exposures were 2.23, 1.40, 0.91 and 0.2. For 20 s, reductions were 2.98, 2.14, 1.17 and 0.1. There was a significant ( P < 0.05) linear relationship between log reductions and T _f which varied with exposure time. At a T _f of 83.5°C with exposure times greater than 20 s, carcass bloom was judged to be permanently and adversely affected. At shorter times or with lower temperatures this did not occur.
Evaporative heat losses were well correlated with the pressure driving force ( r = 0.89) and gravity driving force ( r = 0.92) for air interchange between the cabinet and its surrounds.
The running cost using the distributor cabinet was one-third of that of an existing spray cabinet when compared at the maximum reduction of log 1.3 (95%) achieved by the spray cabinet. An additional advantage of the distributor cabinet is its constructional simplicity.     

A critical examination of some experimental variables in the 2-thiobarbituric acid (TBA) test for lipid oxidation in meat products

By comparison of various procedures for the determination of TBARS (2-thiobarbituric-acid-reactive substances) in non-cured meat samples, it was found that a direct extraction procedure with trichloroacetic acid gave significantly higher reaction yields than a rapid Kjeltec steam distillation procedure (50 ml distillate in 2.5 min). When optimizing the distillation procedure with regard to distillation principle (heating by thermal conductivity or steam injection) and rate, the reaction yield was more affected by changes in distillation principle than by changes in distillation rate. Simple distillation (conduction heating) yielded significantly higher TBA values than steam distillation at the same distillation rate. The reproducibility of the distillation procedure was found to be about 5–10 times poorer than of the extraction procedure and, because of the high reaction yields and robustness of the extraction procedure, the use of the extraction procedure is recommended with food matrices such as non-cured meat samples with less than 14–18% fat and no artificial colorants.     

Beef Marbling and Color Score Determination by Image Processing

Sixty steaks with various degrees of marbling and color were subjected to sensory evaluation and image processing. Marbling and color scores were assigned to each steak with USDA marbling score cards and a lean color guide. Images were recorded for each steak under the same conditions as used for sensory analysis. Steak images were processed for color and marbling characteristics. Image processing effectively predicted the lean color (R²= 0.86) and marbling scores (R²= 0.84). Image processing was an effective tool for determining USDA quality attributes of fresh meat.     

Total Process Lethality as Related to Residual Catalase Activity in Cooked Chicken Breast

We investigated the effects of total process lethality on the decomposition of hydrogen peroxide, presumably due to catalase activity. Ground chicken breast meat was heated to various end-point temperatures (EPTs) in 10 heating treatments varying heating time and rate. Within each treatment, residual catalase activity was affected by the product EPT. However, samples heated to the same EPT under different treatments retained less enzymatic activity as heating time increased. Total process lethality was calculated to assess the severity of heating at each EPT under each heating condition. Residual enzymatic activity was directly related to the total lethality.