Does High Hydrostatic Pressure Affect Fruit Esters?

The effect of high hydrostatic pressure on ester formation and hydrolysis was studied. Six esters and the corresponding carboxylic acids and alcohols were subjected to high-pressure treatments of 400 and 800 MPa under three different pH conditions (namely, buffer solutions of pH 4, 6 and 8). The selected compounds were dissolved into buffer solutions, subjected to the pressure treatment and then extracted using dichloromethane. The analysis and quantification were carried out by gas chromatography with flame ionization as detector. High pressure appeared to have no effect on ester formation or hydrolysis under the investigated conditions. In all cases, a small decrease at the levels of carboxylic acids and esters was observed without any evidence of further reaction. This decrease, referred to as decomposition, depended on pressure and pH conditions. Ester decomposition was minimised when a high-pressure treatment of 400 MPa in basic conditions (pH 8) was applied. Carboxylic acid decomposition was minimal in basic conditions and it was independent of the pressure applied.     

超高压处理对胡萝卜压差膨化效果的影响

该文以膨化后产品的脆度和色泽为指标,通过对压力、保压时间和温度及其交互作用影响因素的试验分析,探究超高压处理对胡萝卜膨化效果的影响,确定胡萝卜压差膨化超高压前处理工艺参数.研究结果表明:超高压处理压力和保压时间对产品脆度和色差值的影响较为显著,而温度对胡萝卜膨化效果影响不显著.超高压压力和保压时间对胡萝卜脆度和色差值的...     

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。     

Influence of pre-treatments on microbial load of stored dehydrated onion slices

Onions slices were pre-treated in potassium meta-bisulphite (KMS) and sodium chloride with different concentration levels to study the microbial load of tray and greenhouse-dried onion slices up to 6 months of storage. Data were analysed as per procedure of one-way classified anova using DMRT of AgRes statistical package for bacteria, yeast, fungi and Lactobacilli . Results revealed that in almost all samples, permissible levels of bacteria [18.33 × 10¹ colony-forming units (CFU) per gram], yeast (ND), fungi (0.5 × 10¹ CFU g⁻¹) and Lactobacilli (0.25 × 10¹ CFU g⁻¹) were observed after 5 months of storage. All the samples were also found to be free from Escherichia coli and no Mac Conkey growth was noticed. Onion slices pre-treated in 0.25% and 0.50% KMS and dried in tray and greenhouse, respectively, were found best after 6 months of storage period.     

Effects of high hydrostatic pressure on the physicochemical and emulsifying properties of sweet potato protein

The influence of high hydrostatic pressure (HHP) treatment on the physicochemical and emulsifying properties of sweet potato protein (SPP) at various concentrations, e.g. 2%, 4% and 6% (w/v, SPP‐2, SPP‐4 and SPP‐6), was investigated. Significant differences in hydrophobicity, enthalpy of denaturation and solubility were observed (P < 0.05). Emulsifying activity indexes (EAI) of SPP‐2 and SPP‐6 increased at 400 MPa, whereas EAI of all SPP significantly decreased at 600 MPa (P < 0.05). Emulsion stability (ESI) was significantly decreased for SPP‐2 and SPP‐6, while increase in ESI was observed for SPP‐4 above 200 MPa (P < 0.05). SPP‐2 emulsions showed sharp decrease in apparent viscosity with pressure increase, while pseudo plastic flow behaviour was not changed for all of emulsions. Sporamins A and B were well‐adsorbed in pressurised emulsion without displacement. These results suggest that HHP treatment could be used to modify the physicochemical and emulsifying properties of SPP.     

超高压对牛乳清蛋白水解影响的研究进展

主要综述了国内外关于超高压处理对牛乳清蛋白水解及其产物功能特性影响的研究进展,并展望了超高压处理在酶法制备乳清蛋白生物活性肽方面的应用前景。      

超高压对大豆蛋白结构和功能性质影响研究进展

超高压技术被誉为当今世界十大尖端科技之一,它仅引发氢键等非共价键变化来改变大豆蛋白等生物大分子的结构,从而使其功能特性发生变化。本文主要针对超高压对大豆蛋白的结构特性,溶解性、凝胶性和乳化性等功能特性的影响进行综述。并对超高压在大豆蛋白的应用研究领域进行了展望。     

冰温真空干燥压力对猕猴桃切片干燥品质的影响

以去皮的猕猴桃切片为试材,利用冰温真空干燥技术对其进行脱水处理,研究不同干燥压力(150、350、550 Pa)对猕猴桃切片的干燥速率及干燥后品质的影响。结果表明,冰温真空干燥技术可以最大限度的降低营养物质的损失。干燥压力为350 Pa时的干制品品质最好,猕猴桃切片的失水率和糖度分别为70.6%和24.5%,而复水比、V_C含量、色差值分别为4.75、110 mg/(100 g)和20.35。表明冰温真空干燥技术具有良好的应用前景。      

超声处理对类PSE鸡肉分离蛋白结构和乳化特性的影响

碱溶酸沉法得到的类苍白松软渗水（pale, soft and exudative,PSE）鸡肉分离蛋白功能特性较差,研究不同超声功率（0、150、300、450 W）对类PSE鸡肉分离蛋白（以下简称类PSE分离蛋白）结构和乳化特性的影响及其相关性。结果表明：随着超声功率的增加,类PSE分离蛋白的粒径和ζ电位绝对值显著降低（P＜0.05）,粒径分布逐渐从双峰分布转变为单峰分布;十二烷基硫酸钠-聚丙烯酰胺凝胶电泳显示蛋白组成成分没有发生明显变化,而肌球蛋白重链和肌动蛋白的条带强度总体上增强;圆二色谱显示α-螺旋和无规卷曲相对含量增加,β-折叠和β-转角相对含量降低;自由巯基含量、表面疏水性和荧光强度明显增加;通过扫描电子显微镜进一步证实超声处理改变了分离蛋白的结构,并且减小分离蛋白尺寸;超声处理后,类PSE分离蛋白溶解性、乳化活性和乳化稳定性显著提高（P＜0.05）;同时,相关性分析和主成分分析结果表明,超声处理后类PSE分离蛋白乳化特性的提高与其结构的改变存在高度相关性。综上,超声处理能够改变类PSE分离蛋白的结构并提高其乳化特性,为类PSE鸡肉深加工提供一定的参考依据。     

Effect of high hydrostatic pressure to sweet potato flour on dough properties and characteristics of sweet potato‐wheat bread

The effect of high hydrostatic pressure (HHP, 100–400 MPa) for 20 min at 25 °C to sweet potato flour (SPF) on dough properties and characteristics of sweet potato‐wheat bread was investigated. The particle size of SPF after HHP was decreased significantly. The obvious rupture was observed in granules of SPF after HHP at 300 and 400 MPa by scanning electron microscopy (SEM). After HHP, significant differences on endothermic peak temperatures (T_P) of SPF were observed by differential scanning calorimetric (DSC), of which the enthalpy change (ΔH) had a slight increase, expect that at 200 MPa. Gas retention of dough with SPF after HHP increased markedly from 1199 (0.1 MPa) to 1246 ml (100 MPa). Specific loaf volume of bread with SPF at 400 MPa was increased significantly, while the hardness and chewiness were reduced. Thus, SPF treated with HHP at 400 MPa could be potentially used in wheat bread production.     

高静压酯化木薯淀粉结构及其理化性质的研究

研究将淀粉的酯化改性在高静压的协同作用下进行。选择木薯淀粉为原料,压力水平300、450及600 MPa,以醋酸酐为酯化剂,合成高静压酯化木薯淀粉。借助偏光显微镜、傅里叶红外光谱仪、粘度计、可见光分光光度计等分析手段,对其结构及理化性质进行系统研究。结果表明,红外光谱显示在1700 cm-1左右形成酯键,随着压力的升高偏光十字并没有明显的变化,说明形成的酯键使淀粉颗粒的晶体结构更加稳定,即使在600 MPa的高压下,淀粉颗粒的结构也不会明显的破裂。高静压协同酯化木薯淀粉的稳定性降低,抗酸性增强,变性淀粉相对原木薯淀粉而言抗老化性明显。450 MPa较300、600 MPa压力水平的冷、热粘度差值最大,其差值为27.56 m Pa·s。以上说明变性淀粉可以在造纸、纺织和化工等领域拥有更广阔的应用前景。     

超高压处理对燕麦淀粉颗粒特性、热特性及流变学特性的影响

淀粉的性质直接影响淀粉原料食品的品质。为探究超高压处理对燕麦淀粉性质的影响,将燕麦淀粉在100～600 MPa的压力下处理30 min,研究燕麦淀粉颗粒特性、质构特性、热特性及流变学特性的变化。结果表明：100～300 MPa处理后,淀粉颗粒表面变化不明显,颗粒粒径减小,400～600 MPa处理后,淀粉颗粒表面变粗糙,并发生坍塌、黏结,颗粒粒径增加;超高压处理可以显著降低淀粉凝胶的硬度、胶着度和咀嚼度,并增加淀粉凝胶的回复性、弹性和黏聚性;热力学参数表明燕麦淀粉在500 MPa和600 MPa处理后发生糊化;动态流变实验表明超高压处理使淀粉糊G’、G’’、tan δ值明显提高,且100 MPa处理后,淀粉黏弹性最好;静态流变实验表明原淀粉和超高压处理淀粉均为假塑性流体,500～600 MPa处理后,触变环面积减少,体系的剪切稳定性提高。本研究为超高压对燕麦淀粉特性的影响提供了理论依据。     

高静压对木薯淀粉理化特性及结构的影响

木薯原淀粉因存在不溶于冷水、易老化等诸多性质上的不足,极大地限制了其在食品、药品等领域的应 用。为了优化木薯淀粉的产品特性,通过对木薯淀粉进行高静压（200～600 MPa）改性处理,来优化其性质并拓 展其应用范围。结果显示高静压处理后木薯淀粉颗粒形貌发生明显变化,透光率、溶解度和膨润力均下降,老化值 增大,特别是在600 MPa改性处理后变化最明显,且失去偏光十字;此外,高静压处理后的木薯淀粉表观黏度低于木 薯原淀粉,剪切稀化现象更加明显。木薯原淀粉在经高静压处理后虽然晶型有一定的变化,但没有形成新的基团。     

高静水压和热处理对荞麦蛋白功能性质的影响

高静水压(high hydrostatic pressure,HHP)处理技术作为一种新型的非热食品加工技术,在食品加工中具有对食物营养和感官品质破坏较小等多种优势.本实验通过HHP处理与传统热处理法(heat treatment,HT)处理养麦蛋白(buckwheat protein,BWP),并测定BWP溶解性、起...     

超高压和热处理对低糖柑橘酱品质及流变特性的影响

本实验以‘九月红’脐橙、宜昌蜜橘为原料,在不添加增稠剂的情况下,分别采用超高压（500 MPa、10 min）和热处理（100℃沸水浴加热30 min）方法制备两种低糖柑橘酱,通过对理化指标、感官指标、色泽、流变特性和质构特性等的分析,探究超高压处理和热处理对低糖柑橘酱品质及流变特性的影响。结果显示,超高压和热处理均显著降低了柑橘酱的总酚含量,脐橙酱的总酚含量分别降低13.67%、7.34%,蜜橘酱则分别降低41.41%、15.32%。与未处理组相比,热处理使两种柑橘酱发生明显褐变,总色差（?E）均大于2,超高压处理则显著提高了两种柑橘酱的亮度（L*值）（P<0.05）。所有柑橘酱样品均为剪切稀化的假塑性流体,储能模量（G’）和损耗模量（G”）随振荡频率的增加而增大,呈现频率依赖性,且G’始终大于相对应的G”,表现为以弹性为主的黏弹体特征。就脐橙酱而言,在0.1～100 rad/s范围内,热处理组G’最大（757.2～4 390.5 Pa）,超高压组G’次之（375.5～2 641.5 Pa）,未处理组G’最小（177.25～973.95 Pa）;蜜橘酱数据变化趋势类似。此外,与...