高压二氧化碳保鲜双孢蘑菇的工艺优化

为了优化高压二氧化碳(high pressure carbon dioxide,HPCD)保鲜双孢蘑菇的工艺,在单因素实验基础上,采用响应面法分析HPCD处理压力、处理时间和处理温度对双孢蘑菇硬度和颜色的影响并对其进行优化。结果表明,HPCD保鲜双孢蘑菇的最佳工艺条件为:处理压力0.3 MPa,处理时间3 min,处理温度17℃;与对照相比,该条件HPCD处理后的双孢蘑菇可以更好的保持其硬度和颜色,低温贮藏8 d后的硬度为191.7 N(提高了18.85%),褐变指数(BI)为33.13(降低了16.80%)。因此,HPCD技术可以应用于双孢蘑菇的贮藏保鲜,具有良好的前景。     

香菇速冻前漂烫预处理工艺优化研究

本文旨在建立最大限度地保持香菇微观质构的速冻前预处理工艺.采用响应面方法研宛香菇的漂烫温度和时间对香菇品质的影响.通过中心优化组合设计得出速冻香菇最佳预处理工艺为:漂烫温度93.61℃、瀑烫时间2.32min.香菇经此漂烫预处理工艺,并于-35℃冻结7 min,解冻后透射电镜结果显示香菇微观质构良好.建立了漂烫温度、漂烫时间与过氧化物酶酶活相关性的数学模型,可充分预测瀑烫预处理对过氧化物酶酶活的影响.     

高压二氧化碳技术对叶绿素酶活性的影响研究

高压二氧化碳(High Pressure Carbon Dioxide,HPCD)技术是一种新型的非热加工技术,对食品中的微生物和内源酶有很好的杀灭效果及钝化作用。为研究此技术对酶活的影响,以叶绿素酶为研究对象,在不同温度、压强和时间条件下进行HPCD处理,测定酶活的变化,并分析55℃、30 MPa、不同处理时间条件下叶绿素酶活的恢复情况。试验结果表明:较高的温度、压强及较长的处理时间能够产生较好的钝酶效果,55℃、30 MPa处理45 min,叶绿素酶活下降94%;同时,HPCD钝化酶存在一定的可逆性,不同处理时间条件下,叶绿素酶活的恢复程度差异较大。本文可为叶绿素含量丰富的果蔬加工制品品质控制以及新型的护绿技术提供试验依据。     

超声渗透处理对香菇脱水复水性的影响

为了明确超声渗透在缩短香菇干制时间及提高复水性中的作用,本研究以鲜香菇为材料,研究了超声波功率、超声时间、渗透液浓度三个因子对香菇干制时间和复水性的影响,在单因素试验基础应用正交试验优化了香菇超声渗透工艺条件。结果表明:三因素对香菇干制时间,产品还原糖、氨基酸保留量、亮度(L*)、复水比均有影响。就干制时间而言,因素影响大小为超声波功率 > 渗透液浓度 > 超声处理时间。香菇超声渗透脱水的最适工艺条件:超声波功率为250 W、超声时间为15 min、渗透液浓度为15%。在该条件下,香菇干制时间为7.4 h,复水比为4.55。这表明,渗透结合超声可以提高香菇干燥效率和产品品质。     

脱臭紫甘蓝色素“返臭”的跟踪研究

研究紫甘蓝色素经高压二氧化碳(HPCD)技术脱臭后,在贮藏过程中能否保持稳定无异味状态。采用8 MPa、50℃下处理60min、迅速卸压(2 min)的HPCD处理对紫甘蓝色素中异味物质进行脱除。通过气质联用(GC-MS)色谱技术,对脱臭后不同贮藏时间(3、5、10、15d)内紫甘蓝色素中的异味物质进行跟踪分析。结果表明:HPCD脱臭后的紫甘蓝色素在贮藏过程中存在返臭现象。经过15d的贮藏,对异味贡献最大的含硫化合物的相对百分含量随贮藏时间的延长呈递增趋势,由1.48%增至46.61%,该色素中的核心异味物质烯丙基异硫氰酸酯(AITC)的相对百分含量由1.06%递增至31.98%,其他异味物质的含量也不断增加。     

高压CO2杀菌技术对猪肉糜中枯草芽孢的作用

通过对影响高压CO2杀菌技术(HPCD)的主要因素温度、压力、保压时间进行分析,利用正交试验,以杀灭猪肉糜中枯草芽孢的致死率为指标,对猪肉糜中枯草芽孢的杀菌条件进行优化,并优选出辅助试剂来协同HPCD进行灭菌,在此基础上,推测HPCD致死枯草芽孢的机理.结果表明:HPCD能有效杀灭枯草芽孢,3个因素对杀菌效果的影响程度为压力>保压时间>温度,最优参数组合为30MPa、40℃、保压60min,致死率可以达到3.39.添加辅助试剂的最佳杀菌方式为:既添加芽孢的萌发剂又添加天然抑菌剂,致死率可达5.16.单独添加萌发剂的效果要好于单独添加天然抑菌剂的,故猜测HPCD致死芽孢的机理为先促使芽孢萌发而后将其营养体杀死.     

甜玉米速冻前热烫工艺研究

对甜玉米速冻前热烫工艺进行了研究,通过PPO、POD等酶活性、可溶性糖和Vc等指标的检测分析和感官评价,探讨了水煮热烫处理、蒸气热烫处理和微波热烫处理等热烫处理方式、热烫处理时间等因素对速冻甜玉米品质的影响。试验结果表明,适宜的热烫处理工艺(蒸气热烫20min)能减少可溶性糖和Vc的损失,同时钝化PPO和POD酶活性,提高速冻甜玉米的品质。     

烹饪用香菇醪糟汁的研制

以香菇和糯米为主要原料,采用发酵法研制烹饪用香菇醪糟汁,通过单因素试验确定香菇添加量、药酒添加量、接种量、发酵温度为影响因素,以感官评分为评价指标,采用正交试验对工艺条件进行优化。结果表明:烹饪用香菇醪糟汁最佳工艺条件为酒曲添加量0.4g/100g、发酵时间6天、发酵温度24℃、香菇添加量30g/100g。     

香菇鸡肉酱加工工艺研究

文章介绍了香菇鸡肉酱的制作工艺与操作要点,以香菇、鸡肉为主要原料,考察了制酱过程中香菇和鸡肉配比、食用油添加量、豆瓣酱添加量以及炒制时间等因素对肉酱感官品质的影响,结合单因素试验和正交试验设计,对香菇鸡肉酱的加工工艺进行了优化。结果表明:香菇鸡肉酱的最佳加工工艺为香菇、鸡肉丁配比7∶3,食用油和豆瓣酱添加量分别占香菇鸡肉丁的30%和85%,炒制6min。在此配方工艺条件下,香菇鸡肉酱色泽油亮,口感风味最佳。     

香菇中酚类物质的微波提取工艺的研究

采用微波提取技术对香菇中的酚类物质进行提取,并通过单因素和正交试验对其提取工艺进行了优化。结果表明,最佳提取工艺为:乙醇体积浓度60%,微波功率400 W,微波时间30 s,料液比1∶25,此条件下香菇中酚类物质的提取率为9.24%。     

高压二氧化碳对冷却猪肉品质的影响

高压二氧化碳(high pressure carbon dioxide,HPCD)在肉制品中的杀菌效果显著,应用潜力巨大。但是,目前关于HPCD对肉类食品品质影响的研究几乎没有。因此,本研究针对HPCD处理对冷却猪肉色度、嫩度、水分损失和储藏期TBA值的影响展开研究,这对HPCD处理在生产中的实际应用具有一定借鉴意义。     

高压二氧化碳和超高压对多酚氧化酶和果胶甲酯酶结构的影响

为考察高压二氧化碳(HPCD)和超高压技术钝化多酚氧化酶(PPO)和果胶甲酯酶(PE)活性的机理,采用SDS-PAGE电泳、红外光谱和荧光光谱对处理前后酶蛋白的结构进行比较研究。结果表明：经过不同压强HPCD处理和超高压处理60min后,PPO和PE的活性均随着处理压强的增大而逐渐降低。SDS-PAGE电泳分析显示处理后酶蛋白的肽链不发生断裂,但红外光谱和荧光光谱分析显示酶蛋白的二级和三级结构均发生变化。因此,HPCD和超高压技术通过改变PPO和PE酶蛋白的结构达到钝化酶活性的目的。     

A comparative study of inactivation of peach polyphenol oxidase and carrot polyphenol oxidase induced by high‐pressure carbon dioxide

The inactivation of polyphenol oxidase (PPO) in peach juice and PPO in carrot juice was investigated by high‐pressure carbon dioxide (HPCD), and their inactivation kinetics was analysed and compared. The temperature was 35–55 °C, the pressure was 5–15 MPa under HPCD condition. Results showed that HPCD enhanced the inactivation effect of the temperature on the two PPOs. The inactivation kinetics of peach PPO was well fitted to a first‐order kinetic model, of carrot PPO to a fraction‐conversion model as a function of temperatures or pressures. Susceptibility of the rate constant k of peach PPO was not altered and of carrot PPO was lessened to the temperature, but the susceptibility of the rate constant k of peach PPO and carrot PPO to the pressure was not changed when the pressure was >8 or 12 MPa, indicating the presence of a threshold pressure.     

Membrane permeabilization and cellular death of Escherichia coli, Listeria monocytogenes and Saccharomyces cerevisiae as induced by high pressure carbon dioxide treatment

In this study, the relationship between (irreversible) membrane permeabilization and loss of viability in Escherichia coli, Listeria monocytogenes and Saccharomyces cerevisiae cells subjected to high pressure carbon dioxide (HPCD) treatment at different process conditions including temperature (35–45 °C), pressure (10.5–21.0 MPa) and treatment time (0–60 min) was examined. Loss of membrane integrity was measured as increased uptake of the fluorescent dye propidium iodide (PI) with spectrofluorometry, while cell inactivation was determined by viable cell count. Uptake of PI by all three strains indicated that membrane damage is involved in the mechanism of HPCD inactivation of vegetative cells. The extent of membrane permeabilization and cellular death increased with the severity of the HPCD treatment. The resistance of the three tested organisms to HPCD treatment changed as a function of treatment time, leading to significant tailing in the survival curves, and was dependent on pressure and temperature. The results in this study also indicated a HPCD-induced damage on nucleic acids during cell inactivation. Transmission electron microscopy showed that HPCD treatment had a profound effect on the intracellular organization of the micro-organisms and influenced the permeability of the bacterial cells by introducing pores in the cell wall.     

高压二氧化碳在肉品杀菌保鲜中的应用研究进展

肉及肉制品营养价值高,是人类优质蛋白质的重要来源。但是肉品在加工和流通等过程中容易受到各种来源的污染,导致肉质腐败,甚至诱发食源性疾病。高压二氧化碳（High pressure carbon dioxide, HPCD）是一种新型非热加工技术,可在相对温和的压力和温度条件下达到显著的杀菌效果。本文总结了HPCD的杀菌机制,综述了近年来国内外HPCD技术在肉品杀菌保鲜中的应用研究进展,并阐述了单一HPCD技术及其与其它方法联合处理对肉品中微生物的杀灭效果、肉品理化品质、质构特性和微生物稳定性的影响,针对当前存在的问题,对HPCD技术的发展前景进行了展望。     

Inactivation of polyphenol oxidase from frozen red raspberry (Rubus idaeus L.) by high pressure carbon dioxide treatment

The effect of high pressure carbon dioxide (HPCD) treatment on polyphenol oxidase (PPO) from frozen red raspberry (Rubus idaeus L.) was evaluated. Moreover, the inactivation kinetics of its PPO was simulated by first‐order reaction theory. The minimum of PPO residual rate was 36.6% under 30 MPa and 55 °C for 60 min by HPCD treatment, while that was 66.8% at 55 °C for 60 min by thermal treatment. Moreover, the decimal reduction time of PPO decreased rapidly after HPCD treatment, compared to that of the thermal treatment. The thermal treatment at 55 °C takes a similar time to reach 10% PPO residual rate with HPCD treatment under 30 MPa at 35 °C. One reason for the results was that activation energy of PPO reduced from 98.9 to 14.6 kJ mol^?1 after HPCD treatment. Therefore, HPCD treatment showed stronger capacity to inactivate PPO from frozen red raspberry than the thermal treatment at same temperature.     

高压CO2与超高压均质协同杀菌装置的研发

高压CO_2杀菌和超高压均质杀菌都是非常有前途的非热杀菌技术。为了进一步提升其杀菌能力,把高压CO_2杀菌与超高压均质杀菌有机地结合起来,构建一个新型的高压CO_2与超高压均质协同杀菌技术,并对其工作原理、工作特点、结构组成进行系统的阐述,搭建协同杀菌试验平台。通过酿酒酵母的杀菌试验,验证了协同杀菌系统优于单一的高压CO_2杀菌或超高压均质杀菌。     

The effect of high pressure carbon dioxide on the inactivation kinetics and structural alteration of phenylalanine ammonia-lyase from Chinese water chestnut: An investigation using multi-spectroscopy and molecular docking methods

The effect of high pressure carbon dioxide (HPCD) on the inactivation kinetic and structure of phenylalanine ammonia-lyase (PAL) from Chinese water chestnut (CWC) was studied in this paper. The inactivation kinetic of PAL treated by HPCD (1–4 MPa, 35–55 °C, and 5–60 min) were determined and fitted to the first order kinetics model with calculating kinetic parameters. As revealed by the circular dichroism spectral, the α-helix and β-turn content in secondary structure increased and the β-sheet content decreased. And the intensity of the fluorescence spectra reflecting tertiary structure decreased, together with the λ_max blue-shifted with the increasing pressure. Fluorescence and circular dichroism spectral results indicated that the conformation of PAL was altered by HPCD. The findings of particle size distribution and ζ potential showed that HPCD could cause the aggregates of PAL particles. Moreover, molecular docking indicated the interactions between small molecules (CO₂, H₂CO₃, HCO₃⁻, and CO₃²⁻) and PAL might result in a decrease in PAL activity by forming steric hindrance, preventing substrate from binding. Finally, this paper proposed a potential mechanism for inactivation of PAL by HPCD treatment, where the loss in PAL activity was correlated to changes in secondary and tertiary structure of PAL, which was induced by aggregation effect of HPCD.     

响应曲面法建立乳酸菌高压二氧化碳杀菌模型

采用三因素三水平的Box-Behnken设计,利用响应曲面法(RSM)对影响高压二氧化碳(HPCD)杀菌效果的主要因素(温度、压力和时间)进行研究,以杀灭乳酸菌的对数值为响应函数,建立了猪肉糜中乳酸菌的HPCD杀菌模型.对模型进行变异分析、决定系数分析、t值检验、共线性分析和显著性因子对杀菌效果影响的分析结果表明,采用二阶效应模式构建的模型显著性好、准确度高;显著因子时间、压力的二次方、温度-压力交互项、压力、温度对模型的重要性依次递增且其独立性可靠;温度、压力和时间均能增强HPCD对乳酸菌的杀菌效果.