超高压处理对复合果汁微生物和品质的影响

以苹果、石榴、布朗李制备复合果汁,对不同配比的复合果汁进行感官评价以确定最佳配比,并研究超高压(HHP)处理参数(处理压力、保压时间)对复合果汁微生物和品质的影响。通过感官评价确定复合果汁的最佳复配比例为m_(苹果汁)∶m_(石榴汁)∶m_(布朗李浆)=16∶3∶1。在400 MPa/5 min,500 MPa/1 min,500 MPa/3 min,500 MPa/5 min超高压处理条件下菌落总数、霉菌和酵母数均符合GB 7101-2015 《食品安全国家标准饮料》要求。与未处理组相比,HHP处理和热处理后样品的pH值、可溶性固形物含量和色泽均无显著性变化。HHP处理样品的总酚和抗坏血酸含量与热处理组样品无显著性差异,而HHP处理样品的DPPH自由基清除能力和铁还原能力显著高于热处理组样品。其中,HHP处理组DPPH自由基清除能力较热处理组高8.57%～18.10%,铁还原能力高11.50%～24.78%。HHP处理使样品的黏度上升,而热处理使样品的黏度下降。HHP处理和热处理都使样品的挥发性香气成分发生改变,而热处理后蒸煮味成分含量增加更多。与热处理相比,HHP处理对内源酶活性的钝化能力较弱,多酚氧化酶、过氧化物酶和脂肪氧化酶残存酶活分别在65.13%～76.97%,75.00%～85.42%,75.00%～85.00%范围,而热处理组为15.35%,7.29%,45.00%。     

超高压处理对复合山药泥贮藏期间品质变化的影响

该研究以山药、秋葵、猕猴桃为原料制备得到的复合山药泥为研究对象,对比分析了超高压（High Hydrostatic Pressure,HHP）处理（400 MPa/5 min,400 MPa/10 min,500 MPa/2 min）和热处理（Thermal processing,TP）（97 ℃/2 min）对复合山药泥在4 ℃下贮藏24 d中微生物、营养成分、抗氧化性、内源酶活性及粒径等品质指标的影响。结果表明,贮藏期间,HHP能很好地抑制微生物生长,400 MPa/5 min和500 MPa/2 min处理样品菌落总数均小于1 lg CFU/g,且所有处理样品中均没有霉菌和酵母菌检出;相比于TP处理,HHP处理后的复合山药泥的总酚含量提高了60.66%~227.54%,因此在贮藏期间其抗氧化能力相对更强;贮藏期间,HHP组的?E显著小于TP组,24 d后TP组的?E达到了25.26,而500 MPa/2 min组仅为5.44,因此HHP处理更能维护复合果蔬泥在贮藏期间的色泽。但是,由于不能有效抑制PME的酶活,HHP处理组在贮藏期间的粒径和黏度均高于TP处理。综上,HHP处理能够满足复合果蔬泥的商业应用需求,但对内源酶活性的抑制效率不高。     

高含水率脱水猕猴桃超高压预处理工艺研究

探讨了20℃的温度下,不同压力和保压时间对猕猴桃过氧化物酶和多酚氧化酶活性的影响,研究了猕猴桃的抗坏血酸含量、叶绿素含量及色泽在600MPa的超高压下随时间的变化规律,以确定高含水率脱水猕猴桃超高压预处理的工艺条件。结果表明,20℃的温度下,600MPa的超高压保持20min,可基本钝化过氧化物酶和多酚氧化酶的活性,而猕猴桃的抗坏血酸含量、叶绿素含量及色泽得以最大程度的保留。     

黄皮原浆超高压和热杀菌的比较分析

以黄皮原浆为研究对象,分别用超高压(Highhydrostaticpressure,HHP)和热处理(heattreatment,HT)进行杀菌,比较处理前后及4℃贮藏期间黄皮原浆各理化指标的变化。贮藏期结束时超高压组和热处理组菌落总数分别为67.36、43.49CFU/m L,表明黄皮原浆超高压600 MPa/5 min的杀菌能力与热处理85℃/30 min相当;pH、可滴定酸(TA)、可溶性固形物含量(TSS)在两种处理前后及贮藏期间均无显著(p0.05)变化;两种处理后的总酚、抗坏血酸和抗氧化能力在贮藏期间均呈下降趋势,贮藏期间超高压组总酚、抗坏血酸分别下降了11.71%、9.45%,热处理组下降了19.61%、18.92%,说明超高压能更好的保留黄皮原浆中总酚和抗坏血酸含量,减少抗氧化能力的损失;热处理使黄皮原浆中果胶含量提高了23.15%,而超高压处理对果胶含量无显著影响,但能更好的保留原浆贮藏过程中果胶含量;黄皮原浆中有机酸主要为酒石酸、苹果酸、柠檬酸,且酒石酸含量最高,为13.95mg/g,热处理组对有机酸的影响小于超高压组。研究结果为超高压和热处理应用于黄皮原浆加工提供理论依据。     

超高压处理对奶油干酪功能特性及其应用的影响

以奶油干酪为研究对象,探究超高压(high hydrostatic pressure, HHP)室温(25℃)下,不同压力(200,300,400,500 MPa)保压10 min对奶油干酪功能特性(涂抹性、出油性、融化性)的影响,根据探究结果将最适压力处理过的奶油干酪制成芝士蛋糕,探究超高压处理对其感官品质的影响。结果显示：当HHP压力为300 MPa时,其涂抹性和出油性发生显著性变化(P<0.05),分别提高了33.8%和12.8%。当HHP压力≥300 MPa时,干酪表现出更优的融化性,确定HHP处理的最适压力为300 MPa。将经300 MPa/10 min处理的奶油干酪用于制作芝士蛋糕,结果表明,经HHP处理的干酪有较高的感官评分,其制作出的芝士蛋糕的感官喜好度也较高。     

速冻毛豆漂烫工艺

研究了毛豆的不同漂烫工艺,试找出最佳漂烫方式,通过对过氧化物酶失活率、蛋白质、抗坏血酸、叶绿素含量的变化及感官评定等来衡量微波处理、声热处理和热水漂烫对毛豆品质的影响.试验结果表明,声热处理1 min能有效地钝化过氧化物酶,减少蛋白质、抗坏血酸和叶绿素的损失,同时提高了毛豆的感官品质.     

超高压与热处理对荔枝汁品质影响的研究

对比分析了热处理和高压处理达到商业杀菌要求的基础上分别对荔枝汁感官品质的影响,同时探讨分析处理后果汁理化性质和感官品质的变化。结果表明,热处理和高压处理均使果汁总糖含量增加,而总酸含量有所下降,超高压处理后果汁总酸含量相对下降更大。不同杀菌方式处理后果汁中可溶性固形物变化不显著(P>0.05),超高压处理(450MPa,5min)能显著降低单宁的含量,从感官评价角度看,超高压杀菌处理后果汁品质相对于热处理效果更佳,当超高压达到450MPa,保压5min处理后的果汁样品总体评价优于其他条件处理的果汁样品。     

超高压与重组果胶甲酯酶抑制剂联合应用对鲜榨橙汁果胶甲酯酶活性及品质的影响

为了探究超高压与重组果胶甲酯酶抑制剂(recombinant pectin methylesterase inhibitor,rPMEI)联合处理对鲜榨橙汁中果胶甲酯酶(pectin methylesterase,PME)活性及品质的影响,研究了超高压(400、500和600 MPa,5 min,20 ℃)与重组果胶甲酯酶抑制剂对橙汁微生物、PME酶活、色泽和V_C含量的影响。结果表明:超高压处理条件为500 MPa/5 min,rPMEI添加浓度为0.06 mg/mL时,橙汁中的菌落总数、霉菌与酵母菌数均能达到农业行业标准《NY/T 434-2016绿色食品、果蔬汁饮料》所规定的要求,同时PME被完全钝化;橙汁色泽变化显著小于热处理组(ΔE*=1.22<2.26);V_C保留率为85.1%,显著高于热处理组(保留率=8.33%)。     

不同杀菌方式对即食胡萝卜片品质影响的比较分析

本研究将胡萝卜片为代表的中式菜肴半成品(即食胡萝卜片)作为研究对象,研究不同杀菌方式对即食胡萝卜片品质的影响,采用电子舌技术结合感官评价分别对未杀菌胡萝卜片和经巴氏杀菌、超高压杀菌(High hydrostatic Pressure,HHP)、热辅助超高压杀菌(pressure-assisted thermal sterilization,PATS)处理的即食胡萝卜片及贮藏期间(4℃,60 d)的品质进行了对比分析。试验结果表明:主成分分析(principal component analysis,PCA)和线性判别分析(linear discriminant analysis,LDA)结合电子舌技术能将不同贮藏时间不同杀菌方式的胡萝卜有效地区分开,并且可以观察不同样品的品质差异,三种杀菌方式相比较,在15 d内HHP杀菌即食胡萝卜片的品质最好且与未杀菌组品质接近;感官评价结果显示,HHP处理能最大限度地保持胡萝卜的色、香、味、形,感官品质与不杀菌胡萝卜片接近。综上,在贮藏初期,HHP杀菌较PATS和巴氏杀菌能够更好地保持胡萝卜的品质。     

高静压技术对豆浆中脂肪氧合酶的钝化效果及其动力学分析

研究了高静压技术(HHP)对豆浆中脂肪氧合酶(LOX)活性的钝化作用,并进行失活动力学分析。结果表明:HHP处理能显著钝化豆浆中LOX活性。用300～600MPa压力处理5～20min,对LOX活性有显著的钝化效果(P<0.05),并且随处理压力和处理时间的增加,酶的失活率提高。当压力500MPa,保压时间0min时也有一定的钝化LOX效果;当压力600MPa处理10min以上,豆浆LOX活性被完全抑制。用500MPa处理5min,可以达到与传统巴氏杀菌相同的钝酶效果(P>0.05)。HHP技术钝化豆浆LOX的过程可用一级动力学模型拟合(R2>0.900)。随着压力的升高和处理时间的延长,k值逐渐升高,D值逐渐减小;动力学参数ZP和Va分别为125.94MPa和-45.290cm3/mol。HHP技术在钝化豆浆中脂肪氧合酶活性方面比传统巴氏杀菌彻底,效果更好。其在改善豆浆品质方面具有良好的应用前景。     

High hydrostatic pressure treatment and storage of carrot and tomato juices: Antioxidant activity and microbial safety

The application of high hydrostatic pressure (HHP) (250 MPa, 35 °C for 15 min) and thermal treatment (80 °C for 1 min) reduced the microbial load of carrot and tomato juices to undetectable levels. Different combinations of HHP did not cause a significant change in the ascorbic acid content of either juice (P > 0.05). Both heat treatments (60 °C for 5–15 min and 80 °C for 1 min) resulted in a significant loss (P < 0.05) in the free‐radical scavenging activity as compared to untreated samples. HHP‐treated juices showed a small loss of antioxidants (below 10%) during storage. The ascorbic acid content of pressurized tomato and carrot juices remained over 70 and 45% after 30 days of storage, respectively. However, heat treatment caused a rapid decrease to 16–20%. Colour changes were minor (ΔE = 10) for pressurised juices but for heat‐pasteurised samples it was more intense and higher as a result of insufficient antioxidant activity. HHP treatment (250 MPa, 35 °C for 15 min) led to a better product with regard to anti‐radical scavenging capacity, ascorbic acid content and sensory properties (colour, pH) of the tomato and carrot juices compared to conventional pasteurisation. Therefore, HHP can be recommended not only for industrial production but also for safe storage of fresh juices, such as tomato and carrot, even at elevated storage temperatures (25 °C). Copyright © 2007 Society of Chemical Industry     

Effect of high hydrostatic pressure and temperature on carrot peroxidase inactivation

The combined effects of pressure and temperature on the activity of carrot peroxidase (POD) were investigated in the pressure range 0.1–600 MPa and the temperature range 25–45 °C. At lower pressures (<396 MPa), carrot POD stability increased compared to unpressurized samples. Inactivation of 91% was obtained at 600 MPa and 45 °C. High hydrostatic pressure (HHP) combined with temperature treatment enhanced the inactivation of carrot POD. Regeneration of POD activity with the combined HHP and temperature treatments followed first order kinetics at 25, 35 and 40 °C. Regeneration was not observed at 506 MPa and 45 °C. HHP had no significant effect on the loss of vitamin C or on protein content. HHP combined with mild heat treatment was found to be better than the thermal treatment at high temperatures for inactivation of POD in carrot processing.     

HIGH HYDROSTATIC PRESSURE PROCESSING OF PEACH PUREE WITH AND WITHOUT ANTIBROWNING AGENTS

High hydrostatic pressure (HHP) (103 to 517 MPa) was applied for selected times (5 to 25 min) on peach puree with and without the addition of antibrowning agents (1000 ppm ascorbic acid or 300 ppm cysteine). Polyphenoloxidase (PPO) activity was assessed before and after HHP processing. Peach purees were stored at 3C for 13 days and then at 22C for 15 additional days. A z_p value of 224 MPa, in a range from 207 to 517 MPa of pressure, was obtained for peach puree without the addition of antibrowning agents. PPO activation at 103, 207 and 310 MPa or inhibition at 414 and 517 MPa was observed in peach purees containing added ascorbic acid. More than 50% inactivation of PPO was observed after adding cysteine to the peach puree and 99% inhibition was observed after 517 MPa of pressure at the experimental times. The higher the pressure treatment and the longer the treatment time for inactivating PPO, the less the discoloration of the peach puree with and without antibrowning agents during storage at low temperatures.     

Polyphenoloxidase Activity and Color of Blanched and High Hydrostatic Pressure Treated Banana Puree

The effects of blanching and high hydrostatic pressure (HHP) treatments on natural flora evolution, polyphenoloxidase (PPO) activity and color of banana puree adjusted to pH 3.4 and water activity (a_w) of 0.97 were evaluated during 15 days storage at 25°C. Standard plate as well as yeast and mold counts of HHP treated purees were <10 CFU/g throughout storage. Blanching time was found to affect (P<0.05) puree color. HHP treatments retained the initial color of the banana purees. Longer browning induction times and slower browning rates were observed when a longer blanching time was combined with a 689 MPa pressure treatment. A residual PPO activity < 5% was observed in the puree when a 7 min blanch was followed by HHP treatment at 689 MPa for 10 min.     

Effect of high hydrostatic pressure on the quality-related properties of carrot and spinach

This study was designed to evaluate the potential effectiveness of high hydrostatic pressure (HHP) on the changes in quality-related properties of carrot and spinach as measured by ascorbic acid, carotenoids, phenols, flavonoids, microstructure, enzyme activity, and antioxidant activity. Better retention of ascorbic acid and carotenoids was observed at the carrots and spinaches treated at 100, 300, and 500 MPa for 20 min compared to the thermal processing. The color differences were noticeable at the carrot treated at 500 MPa (ΔE=3.5) and the spinach treated at 100 MPa (ΔE=3.6). The least residual peroxidase (POD) activity was 16.6% at the carrot at 300 MPa. The residual polyphenoloxidase (PPO) activities were decreased in carrot (15.1-6.9%) and spinach (31.1–21.3%) and the amounts of phenols flavonoids were increased with increasing pressure levels, leading to the enhanced antioxidant activity. Therefore, the HHP could be used as an alternative for improving quality of vegetables.

     

超高压对菠菜浆贮藏期间颜色变化的影响

为探究超高压技术（HHP）处理菠菜浆的颜色品质在不同贮藏条件下的变化规律,对HHP处理样品的CIEL’a’6’颜色进行测定。结果表明,HHP处理菠菜浆在处理后和贮藏期与传统热处理菠菜浆相比其颜色品质更好。在4~C下进行贮藏,HHP处理样品的一a‘值和h。值均显著高于热处理样品,并且在贮藏期阀基本保持不变;￡_’值在HHP处理后显著增加,在贮藏过程中亦基本保持不变,色泽更为明亮。在27。C下进行贮藏,HHP处理样品的一a’值和h。值均显著高于热处理和未处理样品,并在贮藏期间呈下降趋势;上’值在贮藏过程中呈现曲折上升的趋势。因此,HHP处理菠菜浆的表观绿色在冷藏和室温贮藏条件下均要好于传统热处理。HHP处理可以在一定程度上保持绿色菠菜浆的颜色品质,减缓其颜色品质的劣变。     

Influence of sonication and high hydrostatic pressure on the quality of carrot juice

The combined effects of ultrasound (US) and high hydrostatic pressure (HHP) on enzymes, micro‐organisms, colouring pigments, total polyphenols, ascorbic acid and physicochemical properties of carrot juice were investigated. Carrot juice was treated with sonication (20 kHz, 70% amplitude) and HHP (250, 350, 450 MPa) at room temperature for 10 min. For comparison, fresh carrots were water blanched (WB) at 100 °C for 4 min and carrot juice was then extracted. As results, highest improvements in colouring pigments were observed in WB and US‐HHP450 treatments, which also completely inactivated micro‐organisms. The highest reduction in enzymes was observed in WB treatment followed by US‐HHP450. Total polyphenol contents increased significantly in US, HHP and US‐HHP treatments with the highest increase in US‐HHP450, but it decreased significantly in WB treatment. Ascorbic acid contents significantly decreased in WB and HHP450, while increased in US and US‐HHP treatments. Results indicate that US‐HHP450 treatment improves the quality of carrot juice and serves as a good alternative for blanching treatment.     

Synergistic impact of sonication and high hydrostatic pressure on microbial and enzymatic inactivation of apple juice

The combination of innovative, non-thermal technologies for the production of safe and quality fruit juices is a recent trend in food processing. The purpose of this study was to evaluate the effects of combined treatment of ultrasound (US) and high hydrostatic pressure (HHP) on enzymes (polyphenolase, peroxidase and pectinmethylesterase), microorganisms (total plate counts, yeasts and molds) and phenolic compounds (total phenols, flavonoids and flavonols) of apple juice. Moreover, its effects on ascorbic acid, antioxidant capacity and DPPH free radical scavenging activity, color values, pH, soluble solids and titratable acidity were investigated. Fresh apple juice was treated with US (25 kHz and 70% amplitude) at 20 °C for 60 min with subsequent HHP treatment at 250, 350 and 450 MPa for 10 min at room temperature. The results revealed that the combined US-HHP450 treatment caused highest inactivation of enzymes with complete inactivation of total plate counts, yeasts and molds. It also significantly improved the phenolic compounds, ascorbic acid, antioxidant capacity, DPPH free radical scavenging activity and color values. The present results suggest that the combination of US and HHP can act as a potential hurdle to produce safe and high quality apple juice with reduced enzymes and microbial activity and improved nutrition.     

Effect of high hydrostatic pressure on quality parameters of lager beer

Unpasteurized lager beer samples from a commercial brewery were treated either by high hydrostatic pressure (HHP; 200, 250, 300, 350 MPa for 3 and 5 min at 20 °C) or by conventional heat pasteurization (60 °C for 15 min). The main attributes of the beer, such as ethanol content, extract and pH, were not affected by either treatment; however HHP and heat pasteurization affected colour, chill haze, protein sensitivity and bitterness. Change in bitterness was higher in conventional heat pasteurization, but pressures up to 300 MPa had no significant affect on bitterness. Although more studies should be carried out to investigate the effects of HHP treatment on different types of lagers and ales, our results revealed that HHP could be successfully used to process beer, even at temperatures well below those required for heat pasteurization, without affecting some of the quality attributes. Copyright © 2005 Society of Chemical Industry     

Effect of high hydrostatic pressure on immunomodulatory activity of cloudy apple juice

Present study investigated the effects of high hydrostatic pressure treatment (HHP, 500 MPa/3 min/ 25°C) on bioactive compound as well as antioxidant, immunomodulatory potentials, and microbial safety of cloudy juice from ‘Fuji’ apples. HHP did not cause any significant changes in vitamin C content whereas total polyphenol content was increased. The antioxidant potentials measured by DPPH and nitric oxide (NO) radical scavenging tests were preserved by HHP, while thermal treatment reduced antioxidant potentials. NO scavenging activity was greater than DPPH scavenging activity. The immunomodulatory effect assessed by splenocyte proliferation was increased in a dose-dependent manner, and HHP preserved immunomodulatory activity of apple juice. Furthermore, HHP treated juice was microbiologically safe without any physicochemical changes during 21 days of storage at 4°C. These results demonstrated the efficacy of HHP for preserving both nutritional and immunomodulatory functional characteristics of apple juice, and alternative method for preserving as freshly squeezed for up to 21 days.