热和高静压杀菌对糟卤虾仁货架期及品质的影响北大核心CSCD

为研究热和高静压杀菌对糟卤虾仁品质和货架期的影响,分别采用热和高静压(HHP)方法对糟卤虾仁样品进行处理。根据样品微生物菌落总数随着杀菌时间的变化曲线,确定较优的热和高静压杀菌条件分别为85℃、20min和550MPa、10min。通过理化指标和感官评价对杀菌处理后的样品品质进行评价。结果表明,贮藏过程中,热和高静压杀菌组样品的pH值和水分含量均无显著变化;贮藏30d后,热和HHP杀菌组的综合评分均低于对照组,但是HHP杀菌组样品在形态、色泽、软硬度等方面均优于热杀菌组;贮藏90d后,HHP杀菌组样品的微生物菌落总数达到2.5×104 cfu/g,接近行业标准的上限(3.0×104 cfu/g),远高于热处理组(70cfu/g),相应地,HHP杀菌组的TVB-N值也高于热处理组。     

热和高静压杀菌对糟卤虾仁货架期及品质的影响

为研究热和高静压杀菌对糟卤虾仁品质和货架期的影响,分别采用热和高静压(HHP)方法对糟卤虾仁样品进行处理。根据样品微生物菌落总数随着杀菌时间的变化曲线,确定较优的热和高静压杀菌条件分别为85℃、20min和550MPa、10min。通过理化指标和感官评价对杀菌处理后的样品品质进行评价。结果表明,贮藏过程中,热和高静压杀菌组样品的pH值和水分含量均无显著变化;贮藏30d后,热和HHP杀菌组的综合评分均低于对照组,但是HHP杀菌组样品在形态、色泽、软硬度等方面均优于热杀菌组;贮藏90d后,HHP杀菌组样品的微生物菌落总数达到2.5×104 cfu/g,接近行业标准的上限(3.0×104 cfu/g),远高于热处理组(70cfu/g),相应地,HHP杀菌组的TVB-N值也高于热处理组。     

超高压联合其他保鲜技术在水产品中应用的研究进展

水产品捕捞后,由于微生物与内源酶的作用,在脂肪氧化等其他因素的影响下,感官品质下降,采用适当的处理手段可以延缓其劣变。超高压技术具有压力传递均匀、杀菌效果好、灭酶彻底等特点,能保全食品加工前的色泽、香味及各类营养成分,同时还可以赋予食品新的口感,具有低能耗、高效率、无二次污染、操作简便等优点。在介绍超高压处理技术主要优缺点、工作原理与作用机制的基础上,阐述了该技术在水产品灭菌、钝酶与加工改性等方面的应用研究进展,提出超高压处理可联合物理、化学及生物保鲜技术提升作用效果,并对超高压技术在水产品中的发展前景予以展望。     

应用SRCD和FTIR分析超高压处理对蘑菇多酚氧化酶二级结构的影响

应用同步辐射紫外真空圆二色光谱(SRCD)、傅里叶变换红外光谱(FTIR)和荧光光谱研究了超高压(HHP)处理对蘑菇多酚氧化酶(PPO)二级结构和三级结构的影响。HHP处理使蘑菇PPO的α-螺旋含量明显减少,二级结构发生改变。通过SRCD光谱和FTIR光谱分析得出的未处理或HHP处理蘑菇PPO的二级结构含量均存在一定的差异,这种差异可能是由于测量温度、酶液浓度和分析方法等多种因素造成的。荧光光谱表明,HHP处理后,蘑菇PPO溶液荧光光谱的强度降低,最大发射峰发生了红移,表明HHP处理改变了蘑菇PPO分子的三级结构。     

物理技术在食品贮藏与果蔬保鲜中的应用

将物理技术应用于食品果蔬的杀菌保鲜，为食品贮藏与保鲜工作开辟了一条新的途径，大量实验表明应用辐射场、静电场、高压脉冲电场、微波等物理技术处理食品果蔬可在不破坏食品的营养结构与原有风味的基础上起到杀虫、灭菌、防腐保鲜的作用。文章综述了近年来物理技术在食品杀菌与保鲜方面取得的研究与应用发展，并对其未来的发展方向作了初步展望。     

高静压对菠菜类囊体膜叶绿素和蛋白光谱特性的影响

研究了100、250和500MPa高静压(High Hydrostatic Pressure,HHP)处理对菠菜类囊体膜叶绿素浓度、可溶性蛋白浓度、叶绿素室温吸收光谱、叶绿素发射和激发荧光光谱、蛋白荧光光谱的影响。结果表明,同热处理的菠菜相比,HHP处理的菠菜类囊体膜能保持较高的叶绿素和可溶性蛋白浓度,较高的叶绿素室温吸收光谱、叶绿素发射和激发荧光光谱、蛋白荧光光谱能力,并且在100和250MPa时效果更加显著。另外,HHP处理后的菠菜类囊体膜仍能保持光系统Ⅱ捕光和被激发的能力,同时蛋白荧光光谱的变化也反应出HHP处理后类囊体膜蛋白组分的变化。由此推断,HHP保持绿色蔬菜的颜色品质可能与类囊体膜功能特性的维持有关。     

超高压杀菌机制研究进展

 食品中微生物是导致食品品质降低的重要因素之一,超高压作为一种灭菌方式已取得了显著的效果。介绍了超高压杀菌基本原理,着重分析了超高压对微生物细胞形态结构、代谢、遗传物质等造成的影响,并展望了超高压在食品工业中的应用前景。     

西瓜汁的超高压杀菌效果研究

 研究了西瓜汁常温超高压处理后的微生物存活量与杀菌压力、脉动施压之间的关系,并用VITEK 32型细菌鉴定仪对耐压菌种进行了鉴别。实验杀菌压力范围在100~500 MPa之间、保压时间为10 min、以“加压—保压（10 min）—卸压－停顿（5 min）”为一个脉动施压循环,对西瓜汁样品进行多次循环高压处理。结果表明：在30 ℃、处理压力达到或超过400 MPa时,西瓜汁中微生物含量达到国家食品卫生标准要求;随着脉动施压次数的增加,微生物存活量减少;西瓜汁中残存耐压菌以革兰氏阳性菌为主,达70%,此外还残存有少量革兰氏阴性菌和霉菌。     

高压脉冲电场技术在液体食品杀菌中的应用

利用高压脉冲电场技术对液体食品进行杀菌，可以在不破坏食品的营养结构与原有风味的基础上起到杀菌保鲜作用，本文介绍了杀菌装置的基本结构、杀菌机理、影响杀菌效果的基本因素和存在的关键问题。     

近红外光谱技术在微生物检测中的应用进展

近红外光谱作为一种无损检测技术被广泛应用于农业、制药、食品等领域的多组分品质快速监测。微生物的快速准确检测,在临床诊断、制药和食品加工等领域一直是一个难题。微生物菌体细胞壁、细胞膜及细胞内生物大分子和水的近红外光谱具有高度特异性,因此可以使用近红外光谱快速识别和分类不同的微生物。通过对相关文献的归纳整理与分析提炼,对近红外光谱技术在微生物检测中的研究进展做综述。对微生物的基本知识和近红外光谱技术鉴定微生物的基本原理进行了介绍,并重点综述了近红外光谱技术在微生物分类、食源性微生物检测和成像微生物检测等方面的国内外研究进展,最后对近红外光谱技术目前存在的问题和未来的应用前景进行了展望,以期为今后在微生物检测领域更好地利用近红外光谱提供参考。     

The variability of times to detect growth from individual Clostridium botulinum type E endospores is differentially affected by high pressure treatments

High pressure thermal (HPT) processing is a candidate technology for the production of safe and stable food. However, little is known about the effect of HPT or high hydrostatic pressure (HHP) treatments at ambient temperature on the variability of times to detect growth from individual spores. We investigated this effect by treating Clostridium botulinum type E spores with HHP (200–600?MPa, 20°C) and HPT (600?MPa, 80°C and 800?MPa, 60°C). Our results indicate that the mean detection times increase and the frequency distribution shifts toward longer times when HHP treatment intensity is increased. HPT treatments result in a highly scattered distribution. In contrast, pressure levels ≤300?MPa decrease detection times and heterogeneity of their distribution, which could lead to an increase in the potential risk originating from C. botulinum type E spores. Data provided here could help to refine risk assessment regarding this important food intoxicator.     

High-throughput screening of food additives with synergistic effects on high hydrostatic pressure inactivation of budding yeast

ABSTRACT

We focused on food additives that enhance the effect of high hydrostatic pressure (HHP) treatment for microbial inactivation. We previously isolated Saccharomyces cerevisiae ultraviolet (UV) mutant strain a1210H12 that does not cause a growth delay under specific high pressure treatment conditions. We conceived that it is possible to screen effective food additives in a high-throughput manner by combining strain a1210H12 with a viable cell count method based on liquid culture, named high-throughput microbial pressure inactivation kinetics analysis system (HT-PIKAS). Here, we analyzed the synergistic effect between food additives and HHP treatment on inactivation of strain a1210H12 using HT-PIKAS. We calculated the inactivation rate in the condition of additive only, HHP treatment only and HHP treatment with additive. As a result, four compounds, benzoic acid, sorbic acid, adipic acid and caproic acid, showed high synergistic effects with HHP treatment and could be selected from more than 30 compounds as safe food additives.     

Effect of high hydrostatic pressure and high dynamic pressure on stability and rheological properties of model oil-in-water emulsions

Both static and dynamic high pressure applications provide interesting modifications in food structures which lead to new product formulations. In this study, the effects of two different treatments, high hydrostatic pressure (HHP) and high dynamic pressure (HDP), on oil-in-water emulsions were identified and compared. Microfluidization was selected from among the HDP homogenization techniques. The performance of each process was analyzed in terms of rheological modifications and emulsion stability improvements compared with the coarse emulsions. The stability of the emulsions was determined comparatively by using an analytical photo-centrifuge device employing novel analysis technology. Whey protein isolate (WPI) in combination with a food polysaccharide (xanthan gum, guar gum or locust bean gum) were used as emulsifying and stabilizing ingredients. The effective disruption of oil droplets and the degradation of polysaccharides by the shear forces under high pressure in HDP microfluidization yielded finer emulsions with lower viscosities, leading to distinctive improvements in emulsion stability. On the other hand, improvements in stability obtained with HHP treatment were due to the thickening of the emulsions mainly induced by protein unfolding. The corresponding increases in viscosity were intensified in emulsion formulations containing higher oil content. Apart from these, HHP treatment was found to be relatively more contributive to the enhancements in viscoelastic properties.     

Sterilization of Liquid and Semi-Solid Pharmaceutical Forms Using High Pressure Technology

The aim of this study was to investigate the use of HHP (High Hydrostatic Pressure) technology as a possible alternative method for decontamination and sterilization of sensitive drugs. We demonstrated the safety of HHP treatment on several sensitive biomolecules. A 10 min. HHP treatment inactivates totally pure suspensions of P. aeruginosa , C. albicans and spores of A. niger , but S. aureus needs a longer HHP duration treatment to be totally inactivated. Endospores appear to be more baroresistant.     

Brewing characteristics of piezosensitive sake yeasts

Application of high hydrostatic pressure (HHP) treatment to food processing is expected as a non-thermal fermentation regulation technology that supresses over fermentation. However, the yeast Saccharomyces cerevisiae used for Japanese rice wine (sake) brewing shows high tolerance to HHP. Therefore, we aimed to generate pressure-sensitive (piezosensitive) sake yeast strains by mating sake with piezosensitive yeast strains to establish an HHP fermentation regulation technology and extend the shelf life of fermented foods. The results of phenotypic analyses showed that the generated yeast strains were piezosensitive and exhibited similar fermentation ability compared with the original sake yeast strain. In addition, primary properties of sake brewed using these strains, such as ethanol concentration, sake meter value and sake flavor compounds, were almost equivalent to those obtained using the sake yeast strain. These results suggest that the piezosensitive strains exhibit brewing characteristics essentially equivalent to those of the sake yeast strain.     

Thermal Control Simulation in High Pressure Treatment of Foods

High hydrostatic pressure (HHP) has become in the last few years a promising technology for food processing and preservation. Pressure treatment of foods always results in a temperature increase due to the work of compression. After compression, heat loss through the metal wall of the high-pressure vessel causes temperature gradients in the processed product. So, it is absolutely necessary to know how thermal exchanges in high-pressure treatments are produced and at what rate in order to establish the real conditions at which a given process is realised. In this paper, a modelling/simulation of the thermal exchanges taking place in a high-pressure pilot unit during different processes of pressurisation and depressurisation is presented. Good agreement between simulated and experimental values is found. This work involves an important advance in optimisation and regulation of high-pressure processes in food industry.     

The effect of high hydrostatic pressure on the physiological and biochemical properties of pepper (Capsicum annuum L.) seedlings

High hydrostatic pressure is a non-thermal food processing technology, which also has several successful applications in different areas besides food processing. In this study, Capsicum annuum L. (pepper) seeds are subjected to 50, 100, 200 and 300?MPa pressure for 5?min at 25°C and the seedlings of HHP processed seeds are used to compare percentage of seed germination and biochemical properties such as chlorophyll a, b and a/b, proline content, total protein, carotenoid, malondialdehyde, glucose, fructose and phenolic compounds concentrations. As a result of the study, it was observed that there are remarkable changes in terms of biochemical properties especially for seedlings, whose seeds were pressurized at 200 and 300?MPa. More detailed studies are needed to put forward the mechanism behind the changes in biochemical properties.     

High hydrostatic pressure inactivation of Lactobacillus plantarum cells in (O/W)-emulsions is independent from cell surface hydrophobicity and lipid phase parameters

Inactivation efficiency of high hydrostatic pressure (HHP) processing of food is strongly affected by food matrix composition. We investigated effects of fat on HHP inactivation of spoilage-associated Lactobacillus (L.) plantarum strains using defined oil-in-water (O/W)-emulsion model systems. Since fat-mediated effects on HHP inactivation could be dependent on interactions between lipid phase and microbial cells, three major factors possibly influencing such interactions were considered, that is, cell surface hydrophobicity, presence and type of surfactants, and oil droplet size. Pressure tolerance varied noticeably among L. plantarum strains and was independent of cell surface hydrophobicity. We showed that HHP inactivation of all strains tended to be more effective in presence of fat. The observation in both, surfactant-stabilized and surfactant-free (O/W)-emulsion, indicates that cell surface hydrophobicity is no intrinsic pressure resistance factor. In contrast to the presence of fat per se, surfactant type and oil droplet size did not affect inactivation efficiency.     

Comparison of microbiological loads and physicochemical properties of raw milk treated with single-/multiple-cycle high hydrostatic pressure and ultraviolet-C light

The effects of ultraviolet-C radiation (UV-C, 11.8?W/m²), single-cycle and multiple-cycle high hydrostatic pressure (HHP at 200, 400 or 600?MPa) on microbial load and physicochemical quality of raw milk were evaluated. Reductions of aerobic plate count (APC) and coliform count (CC) by HHP were more than 99.9% and 98.7%, respectively. Inactivation efficiency of microorganisms increased with pressure level. At the same pressure level, two-cycle treatments caused lower APC, but did not show CC differences compared with single-cycle treatments. Reductions of APC and CC by UV-C were somewhere between 200?MPa and 400/600?MPa. Both HHP and UV-C significantly decreased lightness and increased pH, but did not change soluble solids content and thiobarbituric acid-reactive substances’ values. Two 2.5?min cycles of HHP at 600?MPa caused minimum APC and CC, and maximum conductivity. Compared with HHP, UV-C markedly increased protein oxidation and reduced darkening.     

The usage of high hydrostatic pressure (HHP) to control food-borne pathogens in hummus

ABSTRACT

With the increasing demand for fresher, higher quality, minimally processed and safer food, there is a strong necessity to develop non-thermal processing techniques. Also for hummus, which is popular all around the world. In this work, the effect of refrigerated storage on the survival of pathogens in hummus treated by high hydrostatic pressure (HHP) (500?MPa/10?min/room temperature) was evaluated. The cocktail of two Salmonella, four Listeria monocytogenes and two Escherichia coli strains was used in this study. All pathogen types were able to survive in hummus during 60 days of refrigerated storage. HHP-treated samples plated on day 0 successfully achieved a?>?5 log cfu/g reduction for all pathogen types. No residual survivors were present after 30 and 60 days in any of the HHP-treated samples. These results demonstrate that HHP may be a useful technique for the inactivation of pathogens and therefore helpful in designing non-thermal HHP conditions for pressurization of hummus.