Laboratory tests on the elimination of the pinewood nematode (Bursaphelenchus xylophilus) in Pinus pinaster wood by high pressure

The efficacy of high pressure processing, a non-thermal phytosanitary treatment, to eliminate Bursaphelenchus xylophilus in Pinus pinaster wood was evaluated. Infected wood sections and chips were exposed to high pressure processing for 5 min at 5, 15 and 30 MPa. Live nematodes were observed in wood sections and chips treated at 5 and 15 MPa but at 30 MPa no nematodes were detected. The results revealed that high pressure processing was successful in eliminating B. xylophilus from wood materials.     

Energy efficiency and drying rates during vacuum microwave drying of wood

The application of vacuum-microwave drying can dramatically decrease drying times in comparison to conventional kiln drying. Instead of thermal energy for the conventional drying, electric energy is used for heating the material in microwave drying. To investigate the energy efficiency specimens of beech, maple and spruce wood were dried in a semi-industrial and a laboratory vacuum-microwave kiln. Both allowed measurement of the energy consumption during the process. In addition, a continuous monitoring of the weight loss was possible in the laboratory kiln. In the first experiments energy input was controlled manually. To avoid material degradation the process was controlled by measurement of wood surface temperature in further experiments. Energy efficiencies of up to 80% were reached depending on the moisture content of the samples and wood species. Drying rates depended additionally on mass specific energy input. For beech drying rates between 1.0 and 4.5%/min were reached. The period of fairly constant drying rate extended to values below the fibre saturation point. The wood was in most cases free of checks and always free of colour changes because of the short process duration and the absence of oxygen.     

真空浸渍在果蔬加工中的应用

真空浸渍(VI)是将真空技术引入传统的浸渍过程的一种新技术,它能快速地将外部溶液渗入到动、植物组织的结构中,从而改变食品的组分.真空浸渍在果蔬加工中可以有广泛的应用,并有它特殊的优点.本文介绍了果蔬真空浸渍过程中的主要影响因素,总结了该技术近年来用于果蔬加工业的重要进展,最后对真空浸溃技术的应用前景进行了展望.     

压缩预处理中压缩速率对杨木浸注性能的影响研究

以杨木为研究对象,利用压缩预处理的方法,选用0.5mm/min、1mm/min、3mm/min、5mm/min和10mm/min五种压缩速率将木材压缩到压缩率60%,研究其对浸注性能的影响.结果表明:不同的压缩速率均可以有效提高木材的浸注效率,但综合浸注量、恢复率及力学性能各方面因素考虑,3mm/min为最佳的压缩浸注速率     

Experimental determination of the dynamics of vacuum impregnation of apples

ABSTRACT:  Vacuum impregnation (VI) is a food processing method by which air and native solution are removed from porous spaces within a food and replaced by an external solution. In this study, an experimental device based on a previous design was built, including some modifications, in order to investigate the dynamics of the VI process. The device measured the net force exerted by a food sample submitted to the VI process using a load cell. The influence of the vacuum level and sample geometry was well quantified by the experimental procedure and the modified equipment using apple samples (Fuji var.) as a food model. The results indicated that the experimental device proposed in this study, together with the suggested procedure, is a useful tool to investigate the dynamics of VI processes. It is robust and versatile, and has the advantage of not requiring the determination of the water evaporated during the VI process in a separate experiment, which represents an increase in the accuracy of the results.     

Optimizing the schedule for CCA impregnation treatment of rubber wood

could be achieved by using concentrations of the CCA solution of 2–4%, depending on moisture content and thickness of the wood. Also, it was found that the penetration and distribution of chemicals in the treated wood were throughout uniform. Chemical analysis revealed that the distribution of the constituents (copper, chromium and arsenic) of CCA in the treated timber conformed to the desired ratio. This study presents an economical and energy saving schedule for the treatment of rubber wood with CCA preservative. The applicability of the economical schedule developed was tested in two commercial scale treatment units and found suitable.     

腊肉真空腌制工艺条件的优化

以猪脊背肉为原料,研究了真空腌制工艺中真空压力、腌制液浓度、原料质量和真空腌制时间4个因素对其真空腌制速率的影响。单因素实验及正交实验结果表明,腊肉真空腌制的最佳条件为:真空压力86kPa、腌制液浓度25%、原料质量125g、真空腌制时间5h,方差分析结果显示该最佳工艺与其他各组工艺存在着极显著差异。     

Optimizing the schedule for CCA impregnation treatment of rubber wood

3 could be achieved by using concentrations of the CCA solution of 2–4%, depending on moisture content and thickness of the wood. Also, it was found that the penetration and distribution of chemicals in the treated wood were throughout uniform. Chemical analysis revealed that the distribution of the constituents (copper, chromium and arsenic) of CCA in the treated timber conformed to the desired ratio. This study presents an economical and energy saving schedule for the treatment of rubber wood with CCA preservative. The applicability of the economical schedule developed was tested in two commercial scale treatment units and found suitable.     

Application of high hydrostatic pressure to eliminate Listeria monocytogenes from fresh pork sausage.

Ground pork patties were inoculated separately with 10(9) CFU/g each of three strains of Listeria monocytogenes obtained from the National Animal Disease Center (NADC). Inoculated patties were packaged under vacuum and treated at 414 megapascals (60,000 lb/in2) for up to 60 min by high hydrostatic pressure (HHP). Survivors were determined by surface plating onto modified Oxford agar and trypticase soy agar with yeast extract, as well as by the most probable number method using Listeria enrichment broth. Average D values ranged from 1.89 to 4.17 min, depending on the strain, with the most virulent strain (reported by the NADC) having the highest D value. We tested the usefulness of applying a mild heat treatment at 50 degrees C, simultaneously with HHP, to lower these values. Average D values ranged from 0.37 to 0.63 min, depending on the strain. Thus, a 10-log10 reduction could be achieved even in the most pressure-resistant strain of L. monocytogenes by a 6-min application of heat and HHP. Shelf life studies were also conducted, with spoilage levels reached after 5 days of storage at 4 degrees C for controls versus 28 days for treated samples. Sensory evaluation of uninoculated grilled patties showed that panelists could not distinguish between those treated by heat and HHP and untreated controls (P<0.05). Thus, treatment by HHP in combination with mild heating can be used successfully to produce safer, longer-lasting fresh pork without affecting quality.     

Kinematic characterization of the pressure-dependent PCM impregnation process for radiata pine wood samples

This paper reports on the properties of Pinus radiata wood impregnated with an organic phase change material (O-PCM). The tests are aimed at characterizing the kinetics of impregnation (rates, flows, and fronts) and the thermophysical properties (thermal conductivity and specific heat). In particular, a paraffin type O-PCM (octadecane) is used to impregnate dry radiata pine wood in the tangential flow direction at four manometric pressures (0, 1, 2, and 3 bar) and constant temperature of 50 °C. The wood is sapwood from 12-year old P. radiata growing in the Bío-Bío region and dimensioned according to Chilean standard for treated wood sample extraction. The results show that it is viable to impregnate P. radiata wood with O-PCM to improve its thermophysical properties with the purpose of passive conditioning.     

Comparison of vacuum impregnation and soaking techniques for addition of the probiotic Lactobacillus acidophilus to minimally processed melon

This study aimed to evaluate the vacuum impregnation (VI) and soaking methods in the addition of Lactobacillus acidophilusLA‐3 to minimally processed melon (MPM). The melons were washed, sanitised in chlorine solution (200 mg L^?1), peeled and cutted into cubes. Lactobacillus acidophilusLA‐3 (1.4 × 10¹⁰ CFU g^?1) were added to the MPM through both techniques. The L. acidophilusLA‐3 count in MPM was similar to those commonly found in dairy products having probiotic claim, but VI was more efficient than soaking in maintaining the viability (8.61 and 7.98 Log CFU g^?1, respectively). The pH, acidity and soluble solids were not affected by probiotic culture and the incorporation technique; however, the VI affected the firmness of fruit. The MPM was within Brazilian standards for their microbiological characteristics. MPM may be used as a carrier of probiotic bacteria, being one more alternative for individuals who consume probiotic products.     

真空浸渍技术在改善果蔬采摘后的品质特性中的应用进展

针对真空浸渍技术在改善果蔬采摘后的品质特性中的应用及作用原理,以及该技术近些年的研究现状和进展进行了详细综述,为该技术在果蔬采摘后的进一步应用研究提供了参考。     

Reduction in the pH of vegetables by vacuum impregnation: A study on pepper

A method to decrease pH value in pepper slices employing vacuum was studied. The effects of relaxation time (10, 15 and 30 min), vacuum level (200 and 400 mbar) and vacuum application period (2 and 5 min) were evaluated. Results showed that vacuum impregnation (VI) with lactic acid solution increased the acidification degree to a greater extent than processing carried out at atmospheric pressure. In particular, samples treated at 400 and 200 mbar and submitted to a relaxation period of 30 min, showed a reduction in pH ratio (RpH) from 0.929 to 0.894. Otherwise, samples submitted to conventional dipping at atmospheric pressure showed a RpH of 0.968. Vacuum level was found to be the most important variable influencing the variations in total mass and pH. Vacuum impregnation led to an increase in diffusion rate of hydrogen ions into the vegetable tissue due to the increase in contact area between acid solution and cells. Moreover, a direct correlation between pH reduction on the one hand, and vacuum application period and relaxation time on the other, was observed. Results proved that vacuum impregnation process is a useful technique to improve acidification treatments of vegetables.     

New insights into the dynamics of vacuum impregnation of plant tissues and its metabolic consequences

The complex and highly interconnected intercellular air spaces of plant tissues occupied by gas or native liquid has offered the possibility for impregnation with a wide range of compounds. In food processing, the development of vacuum impregnation has allowed a controlled way to introduce these compounds to the tissue structure aiming at modifying structural, nutritional, and/or functional properties as well as improving the processability of fruits and vegetables. In the last 10 years, more than 100 research articles have been published on the topic and significant insights had been gained including improved understanding of mechanisms for mass transfer as well as the development of new, fascinating industrial applications. In the recent years, our knowledge on these aspects has increased by bringing new exploration technologies for studying the impregnation of porous materials and plant cell physiology approaches to bear on the topic. The aim of this paper is to highlight some of these exciting advances. © 2014 Society of Chemical Industry     

Application of vacuum impregnation and CO2-laser microperforations in the potential acceleration of the pork marinating process

The marination of meat takes many hours to attain the required salt content. Vacuum impregnation (VI) and CO₂-laser microperforation have been studied to accelerate the mass transfer process and show promising results. The objective of this study was to investigate the feasibility of reducing the pork marinating time by coupling CO₂-laser microperforation and VI processes and mathematically with Fick's second law and anomalous diffusion models. Pork cylinders were microperforated and marinated with a solution containing NaCl (8% w/w) and Na₅P₃O₁₀ (0.3% w/w) at 6 °C for 60 h. The marinating process was modeled using Fick's second law and anomalous diffusion models. The marinating process coupling VI and microperforations significantly accelerated the mass transfer compared with that of the conventional salting process, reducing the marinating processing time by 47.8%. The anomalous diffusion model was better at representing and adjusting the experimental data compared than the model based on Fick's second law.Industrial applicationThe marinating of meat is a process commonly applied in the meat industry, which focuses on enhancing the flavor, tenderness and juiciness of meat. However, it is a time-consuming process. Laser microperforation is a pretreatment performed on the meat in which the laser acts as a drill, creating micropores in the meat, which coupled with vacuum impregnation can be applied to accelerate the marinating process of pork meat. Applying both technologies, it is possible to reduce the processing time by almost 48%, which can relevantly and significantly increase plant productivity.     

From biorefinery of microalgal biomass to vacuum impregnation of fruit. A multidisciplinary strategy to develop innovative food with increased nutritional properties

A multi-disciplinary approach based on the biorefinery of microalgae biomass (Chlorella sorokiniana) to remove the lipid fraction responsible of the green color and the ‘fishy’ aroma and vacuum impregnation technique to create innovative apple snacks with improved nutritional properties has been investigated. The pressure (150 mbar – 650 mbar), vacuum time (1–7 min) and relaxation time (3–13 min) were modulated by using a Box-Behnken experimental design. The filling of apple pores occurred with a maximum gaining weight of 19.5% and a reduction of porosity fraction from 15.32% to less than 5% but only the pressure and relaxation time significantly affect the level of impregnation. While the texture did not show any difference compared to fresh apples, the color of impregnated apple was affected with minor change in comparison.Industrial relevanceResults positively fuel the food chain sustainability by proposing multidisciplinary tools that combine microalgae cultivation, biorefinery and vacuum impregnation processing capable to improve the nutritional quality of fruit products. Biorefinery is proved to be an essential technology for fractionating chemical compounds from raw microalgae and improving their potential use in food industry as source of nutrient by eliminating some undesired components such as lipid fractions related to the fishy aroma. Finally, the obtained results may be used as basic protocols for the optimization of VI treatments aiming to enrich fruit product of proteins and micronutrients.     

Application of ohmic heating/vacuum impregnation treatments and air drying to develop an apple snack enriched in folic acid

The changes of lifestyle and eating habits of consumers have induced a growth in the demand for functional food. The aim of this work was to study the incorporation of folic acid into apple slices by using ohmic heating (OH) and vacuum impregnation (VI) at 30, 40 and 50 °C and air drying at 50, 60 and 70 °C to obtain an apple snack that is rich in folic acid. The kinetic impregnation of folic acid, texture and color were evaluated. The impregnated samples (VI) at 40 °C and vacuum-impregnated samples with ohmic heating (VI/OH) at 50 °C presented a high content of folic acid, whereas the samples air dried at 60 °C presented an important retention of folic acid. The lowest loss of firmness and color was obtained with the VI/OH treatment at 50 °C with drying at 60 °C. Therefore, the VI/OH treatment at 50 °C followed by drying at 60 °C was determined to be the best process for creating dehydrated apple slices that are rich in folic acid.Industrial relevanceThe aim of this research was to study the incorporation of folic acid into dehydrated sliced apples by using vacuum impregnation/ohmic heating (VI/OH) treatments and air drying technologies and evaluating the mechanical and optical properties of the resulting product. Two technologies, vacuum impregnation (VI) and ohmic heating (OH) were performed at 30, 40 or 50 °C with an electric field intensity of 13 V/cm using conventional heating. The results showed that the samples impregnated of apple slices by VI and VI/OH treatments reached the highest content of folic acid. However, the samples that were dried at 60 °C after impregnation by the VI/OH treatment at 50 °C exhibited an increase in folic acid due to the electropermeabilization effect, which induces retention of folic acid and an increase in the folic acid concentration by decreasing the water content. Under the investigated conditions, the VI/OH treatment at 50 °C followed by air drying at 60 °C may be considered the best processing method to obtain an apple snack that is rich in folic acid.     

A stochastic frontier approach to study the relationship between gastrointestinal nematode infections and technical efficiency of dairy farms

The impact of gastrointestinal (GI) nematode infections in dairy farming has traditionally been assessed using partial productivity indicators. But such approaches ignore the impact of infection on the performance of the whole farm. In this study, efficiency analysis was used to study the association of the GI nematode Ostertagia ostertagi on the technical efficiency of dairy farms. Five years of accountancy data were linked to GI nematode infection data gained from a longitudinal parasitic monitoring campaign. The level of exposure to GI nematodes was based on bulk-tank milk ELISA tests, which measure the antibodies to O. ostertagi and was expressed as an optical density ratio (ODR). Two unbalanced data panels were created for the period 2006 to 2010. The first data panel contained 198 observations from the Belgian Farm Accountancy Data Network (Brussels, Belgium) and the second contained 622 observations from the Boerenbond Flemish farmers' union (Leuven, Belgium) accountancy system (Tiber Farm Accounting System). We used the stochastic frontier analysis approach and defined inefficiency effect models specified with the Cobb-Douglas and transcendental logarithmic (Translog) functional form. To assess the efficiency scores, milk production was considered as the main output variable. Six input variables were used: concentrates, roughage, pasture, number of dairy cows, animal health costs, and labor. The ODR of each individual farm served as an explanatory variable of inefficiency. An increase in the level of exposure to GI nematodes was associated with a decrease in technical efficiency. Exposure to GI nematodes constrains the productivity of pasture, health, and labor but does not cause inefficiency in the use of concentrates, roughage, and dairy cows. Lowering the level of infection in the interquartile range (0.271 ODR) was associated with an average milk production increase of 27, 19, and 9 L/cow per year for Farm Accountancy Data Network farms and 63, 49, and 23 L/cow per year for Tiber Farm Accounting System farms in the low- (0–90), medium- (90–95), and high- (95–99) efficiency score groups, respectively. The potential milk increase associated with reducing the level of infection was higher for highly efficient farms (6.7% of the total possible milk increase when becoming fully technically efficient) than for less efficient farms (3.8% of the total possible milk increase when becoming fully technically efficient).