超高压技术在淀粉改性中的应用

综述了超高压作用对淀粉的糊化特性、淀粉糊的流变学特性、糊化动力学及结晶结构变化等方面的影响,讨论了超高压作用下可能发生淀粉的化学变性,指出应用超高压技术对淀粉进行改性并提高其功能特性的研究具有重要的理论和实用价值。     

氯化钠对玉米淀粉超高压改性的影响

分别用0．5％、1％和5％的NaCl溶液配成5％（W：V）的玉米淀粉悬浮液，在600MPa压力下处理5min，应用偏光显微镜和x．射线衍射仪进行分析测定。结果表明：随着NaCl溶液浓度的增加，玉米淀粉的结晶结构被破坏的程度降低．结晶度增大；5％的NaCl溶液能有效抑制玉米淀粉在超高压作用下的糊化作用。     

Nonthermal starch hydrolysis using ultra high pressure: I. Effects of acids and starch concentrations

Corn starches with 2 mol/l hydrochloric acid (HCl), 2 mol/l sulfuric acid (H₂SO₄) and 2 mol/l oxalic acid (C₂H₂O₄) were pressurized at 600 MPa for 30 min. Corn starch with C₂H₂O₄ formed a gel after ultra-high-pressure (UHP) treatment. Corn starch with HCl showed partial disintegration but starch with H₂SO₄ maintained its shape. Corn starch with HCl showed higher (0.42-0.47) degree of hydrolysis compared to starch with C₂H₂O₄ (about 0.14) and H₂SO₄ (0.13-0.14) regardless of increasing starch concentration up to 20 g/100 g sample. Main component of starch hydrolysate was maltose for HCl and oligosaccharides for H₂SO₄ and C₂H₂O₄. Crystallinity of starch with HCl decreased with decreasing starch concentration as observed by both differential scanning calorimetry (DSC) and X-ray diffraction. Therefore, UHP can be used for nonthermal starch hydrolysis and HCl would be a good catalyst for UHP starch hydrolysis compared to H₂SO₄ and C₂H₂O₄. This work provides a potential of nonthermal UHP processing for new starch hydrolysis method.     

超高压处理对鲜牛奶主要品质影响

为考察超高压处理对鲜牛奶主要品质的影响,在室温条件下对鲜乳施加不同时间以及不同压力的处理,分析测定鲜乳经过超高压作用后其中残留细菌、霉菌和酵母菌的数目,研究了超高压杀菌对鲜乳中这几种微生物致死率的影响和高压对牛奶主要品质的影响。结果表明:压力越高,杀菌效果越好;在同样压力下延长受压时间并不一定能提高灭菌效果。压力处理后牛奶的pH值变化不大,L值会减小。     

石斛多糖超高压提取工艺条件的优化

采用超高压方法提取铁皮石斛中的多糖成分.在单因素实验的基础上,选取压力、时间、粉碎度和固液比(g∶mL)4个影响因素,以石斛多糖为指标,通过正交试验优化超高压方法提取石斛多糖的工艺条件.结果表明,将石斛粉碎到80目后,按固液比1∶20,采用300 MPa的压力提取6 min后,石斛多糖的得率达到19.27%.这表明超高压方法是一有效的提取石斛多糖的方法.     

超高压辅助制备醋酸酯淀粉结构性质研究

以玉米淀粉为原料,乙酸酐为反应试剂,NaCl为反应介质,采用超高压辅助制备醋酸酯淀粉,利用光学显微、X-射线衍射、快速黏度分析技术对醋酸酯淀粉结构性质进行分析。研究表明,颗粒态醋酸酯淀粉结晶类型与原淀粉相同,当处理压力为600 MPa时淀粉糊化,颗粒结构被破坏,A型结晶向V型结晶转换,但糊化并不利于醋酸酯淀粉取代度的增加。适量NaCl的添加有利于超高压处理时淀粉颗粒态的维持,因而有效提高了醋酸酯淀粉的取代度。当NaCl溶液浓度为1.0%、乙酸酐添加量为2.0%、压力为400MPa时,所制备的醋酸酯淀粉取代度达到最大值(0.090),且表现出较高的峰值黏度(400.00cP)。     

天然淀粉的超高压糊化压力研究

在悬浮液浓度为5%(w/v),温度为(20±2)℃时,对8种不同淀粉进行高压处理5 min使淀粉发生糊化,采用X射线衍射测试技术得到了各种淀粉完全糊化的压力:小麦淀粉和木薯淀粉约为500 MPa,玉米淀粉、荸荠淀粉、糯小麦淀粉和糯米淀粉均为550 MPa,糯玉米淀粉约为650 MPa,马铃薯淀粉为750 MPa.     

介质对超高压改性玉米淀粉的影响

分别选用浓度为5%(w/v)的蔗糖、CaCl2、Na2HPO4和NaCl溶液作为淀粉悬浮介质,在570MPa压力下对5%(w/v)的玉米淀粉悬浮液进行高压处理5min,应用偏光显微镜和X-射线衍射仪检测所得样品的结晶性能和结构变化,结果表明:介质对玉米淀粉结构的影响能力从大到小的顺序为5%蔗糖>5% Ca-Cl2>5% Na2HPO4>5% NaCl;5% CaCl2和5% NaCl可以提高处理后的淀粉的结晶度。     

超高压处理对淀粉的影响研究进展

综述超高压作用对淀粉的糊化特性、结晶结构变化、淀粉糊的流变学特性及糊化动力学等方面的影响,指出应用超高压技术对淀粉进行改性并提高其功能特性的研究具有重要的理论和实用价值。     

超高压处理对芥菜制品与生鲜猪肉杀菌效果的研究

以芥菜制品、生鲜猪肉及其经大肠杆菌、金黄色葡萄球菌和枯草芽孢杆菌人工污染的样品为对象，分别经过200MPa，10min、400MPa。10min、600MPa，5min、600MPa，10min、600MPa。15mln、600MPa，20min的超高压处理，测定处理前后的茵落总数。结果表明：试验条件的超高压处理对大肠杆菌、金黄色葡萄球菌的杀灭效果很好，残活率最大下降了8．48、5．90对数；对生鲜猪肉和芥菜制品中的微生物具有较好的杀灭效果，残活率最大下降了3．45、3．57对数。     

Effect of ultra high pressure processing on immuno-modulatory activities of the fruits of Rubus coreanus Miquel

In this study, the most optimal extraction conditions as regards to the immuno-modulatory activity of Rubus coreanus were determined to be 500 MPa with water at 60 °C for 15 min (HPE15). The extraction yield under these conditions was estimated to be 17.3%, which was higher than the yield obtained from the conventional extraction process (13.9%) with water at 100 °C (NE100). For most cases, the extract obtained under a high pressure of 500 MPa for 15 min HPE15 contained higher concentrations of the three main phenolic compounds relative to the conventional extraction procedure; catechin — 5.48 mg/L vs. 3.11 mg/L, caffeic acid — 12.34 mg/L vs. 10.14 mg/L and ferulic acid — 6.94 mg/L vs. 2.59 mg/L. It was found that the high amounts of bioactive components in HPE15 had a stronger beneficial effect on the growth of human B cell (> 20%) and NK cell (> 15%). In addition, the secretion of cytokines, IL-6 (> 10%) and TNF-α (> 12%), and NO- (> 20%) production from macrophages treated with the HPE15 extract was also higher than when the cells were treated with NE100. Based on these combined findings, we concluded that the immuno-modulatory activities of the HPE15 could be enhanced by simultaneous responses of high concentrations of key active components and their synergistic effects. These results clearly proved that high pressure treatment over the appropriate extraction time could effectively destroy the cell membrane and allow the solvents to easily penetrate into the cytoplasm, which can result in the large release of immuno-modulatory active components with less heat damage.

Industrial relevance

High pressure processing has been used for preservation purposes with no or minimal heat treatment where high temperature processing should be avoided. But, this process has not much studied yet on extracting useful compounds which are sensitive to heat from many food resources including medicinal plants even though this technology has many other advantages including a high yield and rapid extraction time within one hour without the need for thermal energy as well as with few impurities.Therefore, the results from this work about analyzing the ultra high pressure extraction process could definitely contribute to wide ranges of food industries for improving extraction yields correlated to their biological activities, which can expand this technology to process various natural resources having much nutritive and functional values as well as to overcome the mechanical limitations of manufacturing ultra high pressure extraction machines.     

超高压加工生鲜牡蛎的研究

研究了超高压处理对牡蛎的杀菌效果及其对产品感官性质的影响。研究结果表明,当超高压达到500MPa后,牡蛎达到商业无菌。600MPa处理的牡蛎在4℃冷藏21d后,总菌落数小于6个对数,仍然符合生鲜牡蛎细菌总数的要求。超高压对牡蛎中不同蛋白酶具有不同的影响。超高压处理使牡蛎的硬度、弹性、咀嚼度、粘结性和恢复力均表现出不同程度的下降,而且超高压处理对牡蛎的色泽产生了一定影响。超高压处理可引起TBA值显著升高,表明超高压引起了牡蛎中脂肪的氧化。     

超高压对胡萝卜-草莓复合汁中酶和微生物的影响

目的：为利用超高压技术加工鲜榨果汁提供依据；方法：采用超高压处理鲜榨胡萝卜-草莓复合汁，发现不同压力、保压时间对复合果汁中POD、PPO和LOX酶的活性及其微生物的致死作用不同；结果：在200，300，400，500，600MPa分别处理20min时，POD最耐压，LOX对压力最敏感，其中600MPa下POD、PPO和LOX分别失活46．15％、52％和77．24％。在400MPa、20min处理的复合汁中大肠杆菌≤3MPN／100mL，细菌总数≤10CFU／mL。     

小麦淀粉的超高压糊化研究

5%的小麦淀粉悬浮液在400MPa、450MPa、500MPa、550MPa压力下处理5min后,再经过干燥处理,所得到的样品用偏光显微镜和X-射线衍射技术对其进行测定,结果表明：经450MPa压力作用后,小麦淀粉已经发生了明显的溶胀;500MPa及其更高的压力作用后,小麦淀粉已经被完全糊化;常温下5%浓度时,小麦淀粉的糊化压力范围为400～500MPa。     

超高压对洛伐他汀生产菌株的诱变研究

为了选育出生产用的高产洛伐他汀菌种,利用超高压对土曲霉出发菌株进行诱变处理,并基于粗糙脉胞菌对洛伐他汀的生物敏感性,对菌株进行初筛,再通过HPLC法检测进行复筛.研究表明,培养3d的菌株处于对数生长期,适宜于试验;压力值为200MPa时能获得最大的诱变率.成功的选育出一株高产洛伐他汀的突变菌株,其抑菌圈直径达25.5mm,比对照高出37.8%;洛伐他汀产量达2.89mg/g,比对照高出18.9%,这一突变菌株具有挖掘潜力,并用于工业生产.     

The effect of high pressure treatment and cryotexturization on odorant mixture binding by corn,sorghum and amaranth starch

The binding extent of odorant mixtures from aqueous suspensions by native, high pressure-treated starches and starch cryotexturizates was studied using capillary gas chromatography. The materials were corn, sorghum and amaranth starches. The native and high pressure-treated (650 MPa/9 min) starches were mixed with odorants and incubated (24 h) at room temperature. To obtain the cryotexturizate-odorant product, starch gels were frozen with odorants (−24 °C), stored (48 h) and thawed. Terpene hydrocarbons were strongly bound from the mixture by all the starches analyzed. The nonpolar molecules of terpene hydrocarbons modified the nature of hydrophobic binding sites in starch which in turn affected binding affinity of alcohols, ketones and phenols to the preparations. The competition effect between odorants for the binding sites was found. The varied ability of starch preparations to bind odorants was also related to the granule morphology and alteration in their structure upon treatment used.     

响应面分析法优化超高压提取柿叶单宁的研究

在单因素实验的基础上,采用响应面分析法对柿叶单宁超高压提取工艺进行优化。以总单宁得率为指标,考察固液比、提取溶剂浓度、压力值、保压时间对得率的影响。获得最佳提取理论条件为:固液比为1:25(g:mL),溶液浓度为56.31%,压力值为222.33MPa,保压时间为3min,总单宁得率为96.19%。与溶剂提取法相比,本方法耗时短,效率高。      

超高压条件下烟叶含水率对香味成分的影响

摘要:为探讨超高压条件下烟叶含水率对香味成分的影响,将烟叶(河南产中部烤烟)在500MPa压力、25 ℃、烟叶含水率为12%～28%条件下处理20min后,利用同时蒸馏萃取和毛细管气相色谱法测定烟叶香味成分的变化,并进行了感官质量评价。结果表明:烟叶香味物质总量在烟叶水分为24%时达到最大值,然后开始下降;酮类物质的变化与香味物质总量的变化趋势相似;而β-苯乙醇、苯甲醇、丁香酚和芳樟醇等香味成分随着含水率的增加而持续增加。感官评价表明:烟叶水分为24%时品质亦最佳。超高压处理可以明显改善烟叶的内在品质,对烟叶陈化加工具有潜在的应用价值。       

高压处理过程中的压力和能量分析

利用高压均质过程作为比较,本文分析了超高压处理过程中流体的压力和能量转化,从而找出了超高压处理过程中没有引起较高温升现象的原因,为进一步理解超高压杀菌技术提供一定的理论基础。