热处理对新鲜椰肉贮藏特性的影响

针对新鲜椰肉在贮藏过程中极易发生腐败变质的问题，研究不同热处理条件对椰肉贮藏特性的影响，筛选最佳的热处理条件。结果表明，60 ℃、25 min热处理结合低温贮藏，能够有效延缓椰肉的腐败变质，显著降低贮藏过程中椰肉的菌落总数、pH值以及内部脂肪的酸价和过氧化值，同时该热处理条件不会对其质构特性产生影响，椰肉的硬度与对照组无显著性差异。     

不同处理对椰肉贮藏期间酶活性的影响

为明确椰肉中酶活性的影响因素,有针对性地控制酶的活动,研究低温、巴氏、80℃烘干、超高温及微波处理对椰肉贮藏期内中脂肪酶(LPS)、过氧化物酶(POD)和多酚氧化酶(PPO)活性的影响。结果表明：-25℃、低温、巴氏、80℃烘干、超高温和微波处理均对椰肉中的LPS、PPO和POD活性有一定抑制作用。对椰肉进行6 d以内的短期贮藏时,80℃烘干处理对脂肪酶、过氧化物酶和多酚氧化酶抑制作用明显;而对椰肉进行6～12 d长期贮藏时,超高温处理效果显著。通过对新鲜椰肉进行不同的处理,可以达到抑制椰肉内酶活性,提高椰肉品质的目的。     

响应面优化大豆乳状液冷冻微波解冻破乳工艺研究

针对大豆水酶法提油过程中产生乳状液难以破乳的问题,在单因素实验的基础上,选取冷冻温度、冷冻时间、微波解冻温度、微波解冻功率和微波解冻时间5个因素为自变量,以乳状液中油脂回收率为响应值,通过SAS9.2进行响应面实验设计。结果表明,最佳条件为:冷冻温度-16.9℃,冷冻时间17.5h,微波解冻温度62.4℃,微波解冻功率666.5W,微波解冻时间10.5min。在此最佳条件下,响应面有最优值为(96.89±1.43)%。采用显微成像观察法分析了水酶法提取工艺形成的乳状液中脂肪球分布情况,通过比对发现冷冻微波解冻破乳后脂肪球粒径明显增大,油脂更易释放。     

红碎茶的摩擦特性

茶叶摩擦性能的研究在制茶工程中有着重要的地位。本研究报告介绍了红碎茶对各种常用茶机材料的摩擦试验方法,分析了红碎茶的含水率、粒度、法向压力、相对运动速度、材料性能和表面状况等因素对红碎茶摩擦性能的影响。研究结果表明,红碎茶对固体材料的摩擦系数随其含水率的增加和粒度的减小而增大,随法向压力的增大和相对运动速度的减小而减小。红碎茶的内摩擦系数大于红碎茶对固体材料的摩擦系数,且随其粒度和含水量的增大而增大。     

动态超高压改性芒果皮渣膳食纤维对果酱流变特性的影响

本研究以芒果皮渣为研究对象,采用动态超高压技术处理芒果皮渣膳食纤维,研究其粒度、膳食纤维含量以及添加了该膳食纤维对果酱流变特性的影响。结果表明：超高压改性提高了芒果皮渣膳食纤维的溶解性;随着压力的增大,膳食纤维粒径先增大后减小再增加,120 MPa时粒径达到18.218 μm。流变特性研究发现,芒果皮渣膳食纤维/果酱复配体系为非牛顿流体,具有假塑性流体特征;果酱粘度随着剪切速率的增大而减小,存在明显的剪切稀化现象;动态粘弹性测试结果表明,果酱复配体系的贮能模量（G′）与损耗模量（G′′）均随角频率的增加而呈上升趋势,损耗正切值也随着压力的增加而增加,在150 MPa时流体性质最明显。     

不同粒径抹茶粉体物化特性研究

以物化特性为指标,利用生产型球磨机将碾茶进行超微粉碎,得到中值粒径为117.094、60.176、40.041、30.646、25.282、21.090、19.199、14.209μm的抹茶,探究不同粒径下抹茶的物化特性。结果表明,随着粉碎时间的延长,粉体粒径逐渐减小,细胞破碎程度显著增加,但茶粉主要成分的官能团结构并未见改变;当粒度细化到一定程度后,比表面积和表面能增大,颗粒处于能量不稳定状态,易发生粘附及团聚现象;粉体的容重减小,这与粉体的孔隙率增大有关;由于茶样比表面积增大,粉体内部物质暴露,使得水分有所减少,总含水量降低;茶粉亮度逐渐升高,绿度增加;随着粉碎时间的延长,样品的茶多酚、游离氨基酸等物质含量呈现先增加后降低的趋势,抗坏血酸和EGCG等物质含量呈现减少的趋势。以上结果表明,超微粉碎过程对抹茶的物化特性总体影响显著。     

普洱茶贮藏过程中主要化学成分含量及感官品质变化的研究

将成品普洱茶在不同条件下贮藏,分析其茶多酚、可溶性糖和氨基酸含量的变化和感官品质的变化,结果表明:贮藏时茶叶含水量和周围环境温度升高,最佳品质出现时间提前,55℃/12%的处理最佳品质出现在贮藏45天左右,37℃/9%的处理最佳品质出现在贮藏135天左右,处理后感官品质明显优于对照。茶多酚、可溶性糖随着贮藏时间延长、贮藏温度提高而下降,且茶叶含水量高者下降幅度大。氨基酸随着贮藏时间延长、贮藏温度提高而下降,但与茶叶含水量相关性不大。     

温度胁迫下宝莲灯的生理及光合特性

以两年生宝莲灯苗为试验材料,利用植物培养箱对宝莲灯植株进行温度处理,研究不同温度对宝莲灯叶片生理及光合特性的影响。结果表明：与对照相比,高温胁迫下宝莲灯叶片的相对电导率、过氧化氢酶（CAT）活性及可溶性蛋白、游离脯氨酸（Pro）、丙二醛（MDA）含量随着温度的升高呈不同程度的增加,而叶绿素含量显著减少,过氧化物酶（POD）、超氧化物歧化酶（SOD）活性呈下降趋势;低温胁迫下相对电导率、Pro、MDA含量随着温度的下降呈上升趋势,可溶性蛋白、叶绿素含量、过氧化氢酶（CAT）活性下降趋势不明显,POD、SOD活性显著降低;随着温度的升高或降低,宝莲灯叶片的光合速率（P_n）、气孔导度（G_s）、水分利用率（WUE）均呈下降趋势,而胞间CO₂浓度（C_i）呈先降低后升高;蒸腾速率（T_r）却随着温度的下降而降低。高温胁迫引起的相对电导率、MDA含量的变化幅度明显小于低温胁迫,而POD、SOD活性高于低温胁迫。说明高、低温胁迫均抑制了宝莲灯的光合作用,宝莲灯对低温胁迫相对较敏感。研究结果对宝莲灯的栽培管理具有指导意义。     

温度与土壤水分对玉米种子萌发及幼苗生长特性的影响

以沈单16、豫玉22为试验材料,研究不同温度、土壤水分对玉米种子萌发及幼苗生长特性的影响.结果表明,随温度与土壤水分的下降种子发芽势、发芽率均呈降低趋势.温度与土壤水分对幼苗生长各指标的影响不同,玉米芽鞘长、幼苗长、贮藏物质转运率和叶绿素含量均随温度与土壤含水量的降低而减小;过氧化物酶活性、脯氨酸含量呈先增加后降低的趋势.在环境温度低于15℃恒温条件下,玉米种子发芽率迅速降低,土壤含水量低于10％时种子不能正常萌发;在15℃及以下低温,土壤含水量低于10％时玉米幼苗生长受到抑制.持续性低温、干旱胁迫不利于玉米种子的正常萌发与幼苗的生长.     

水分处理与耐旱性不同的小麦光合特性及物质运转

本研究表明,小麦群体光合速率和旗叶光合速率均随土壤水分减少而降低,但抗旱性强的旱地品种降低的幅度小,而抗旱性差的水浇地品种降低的幅度大;地上部营养器官贮藏性物质在开花后向籽粒的转移率随土壤水分减少而升高,对粒一的贡献越大,且旱地品种转移率比水浇地品种低。因此,认为提高小麦籽粒产量在水分充足条件下应以促进营养器官贮藏性物质向籽粒运转,提高物质生产的经济转化效率为主;而在水分亏缺条件下就以防止器官的早     

亚麻籽-火麻仁植物乳制备工艺对其稳定性和营养成分的影响研究

为提升富含ω-3功能油脂的系列油料作物在植物乳饮品中的应用,基于亚麻籽和火麻仁的营养特性,以亚麻籽、火麻仁为主要原料,探究了剪切粉碎时间（1~9 min）及火麻仁添加量（1/2~1/6）对亚麻籽-火麻仁植物乳（FHPM）的稳定性和营养成分溶出等的影响,对最优组（剪切粉碎3 min,火麻仁∶亚麻籽=1∶5）所得植物乳的营养素与风味物质组成进行剖析。结果表明,随着剪切粉碎时间增加,植物乳的自稳定性逐渐下降,大于3 min时明显分层,有絮凝现象。研究1~3 min的粉碎时间对营养的影响,发现剪切时间对蛋白质、油脂、膳食纤维、总酚、木酚素的溶出均有显著影响;且随着植物乳中火麻仁所占比例提高,蛋白质和油脂的含量明显提高,但植物乳的自稳定性显著下降,表明植物乳的稳定性与植物乳体系黏度、粒径、电位、颗粒组成等理化特性有关。最优组所得亚麻籽-火麻仁植物乳粒径为4.53 μm,电位为-32.15 mV,固形物含量为5.17 g/100 mL,蛋白质含量为1.32 g/100 g,脂肪含量为3.45 g/100 g,膳食纤维含量为0.47 g/100 g,碳水化合物含量为0.57 g/100 g;植物乳具有合适的表观黏度,可在无外源稳定剂条件下4℃稳定储藏21 d。分析显示该植物乳含有小分子酮类、醛类、醇类等,呈现果味、花香味等良好风味;含有合理的氨基酸和脂肪酸组成。     

Rheological Properties of Short Doughs at Small Deformation

The rheological properties of short doughs of various composition were determined in dynamic shear experiments at small deformation. Regardless of composition, the linear region was very limited; beyond it significant structure breakdown occurred. Furthermore, an increase in storage modulus was invariably observed in time-sweep experiments. In addition to oscillatory experiments, conductimetry was used to evaluate short doughs with different fat types and fat content. Short doughs showed differences in mechanical spectra and in conductivity, depending on fat content and fat type. These results are considered in terms of the structure of short doughs. It is concluded that short doughs are bicontinuous systems; reducing the fat content or changing its rheological properties relative to those of the non-fat phase results in fat-dispersed systems. At small deformation, the rheological properties of the non-fat phase are largely determined by flour/starch particles.     

超微粉碎对工夫红茶物化特性的影响

以物化性质为指标,将工夫红茶超微粉碎成平均粒度为26.116、9.612、4.338、3.742、3.328μm的超微红茶粉,探究超微粉碎对其物化性质的影响。结果表明,随着超微红茶粉粒度减小,堆密度、膨胀力和持水能力变小,休止角和滑角逐渐增大,茶粉流动性变差;色度的L值和b值逐渐增大,表明超微粉碎对工夫红茶色泽有提升作用。内含成分检测结果显示,随着超微红茶粉粒度减小,水浸出物含量、氨基酸含量及可溶性糖的含量明显提高,但是茶多酚、茶色素和粗纤维的含量呈逐渐降低的趋势,推测其原因在于超微粉碎破坏了茶叶中以纤维素为主体的细胞壁结构,粗纤维受到破坏,从而内含成分更容易暴露出来,而多酚类物质不稳定,容易被氧化,因此茶多酚和茶色素的含量才会有降低的趋势。     

不同品牌椰子汁质量的研究

为了更好地了解市售椰子汁的质量状况,本实验以市场上常见的20种不同品牌的椰子汁为样品,通过测量这20个样品的脂肪含量、可溶性固形物含量、蛋白质含量、酸价以及色差,分析了市售椰子汁的质量状况。结果发现:脂肪、可溶性固形物、蛋白质含量达到国家标准QB/T 2300-2006规定的均有19个样品;被测样品的酸价均值为0.86 mg/g,个别样品酸价较大,色差值(Lab值)的变化揭示了椰子汁在颜色上的差异。     

热处理对椰子水过氧化物酶和多酚氧化酶活力及色泽变化的影响

研究热处理对新鲜椰子水过氧化物酶(Peroxidase,简称POD)和多酚氧化酶(Polyphenol oxidase,简称PPO)相对酶活力和色泽变化影响,探讨椰子水酶活力与其色泽的相关性。结果表明,随着热处理温度升高或时间的延长,椰子水的POD和PPO相对酶活力均随之降低,其中90℃和95℃热处理4 min后,可分别使POD和PPO的活力降低90%以上。随着热处理温度的升高,椰子水的色泽随之加深;椰子水的PPO和POD相对酶活力与色泽加深程度呈负相关关系,且具有一定的显著性。该结果可为后续研究椰子水色变控制技术提供一定的理论基础。     

Effect of particle size and addition level of wheat bran on quality of dry white Chinese noodles

Wheat bran is one of the major dietary fiber sources widely used in the food industry in order to produce fiber-rich foods. The effects of particle size and addition level of wheat bran on the quality of flour and of dry white Chinese noodles (DWCN) were investigated. Results suggested that increasing wheat bran concentration and particle size decreased midline peak value (MPV). However, the MTxW and MPT increased as particle size increased. Peak viscosity, trough, final viscosity, area of viscosity, breakdown, and setback of blends decreased significantly with increasing bran levels from 5% to 20%, but there were no significant differences in the impact of particle size on pasting properties. For the 5% and 10% addition levels, there was no distinct effect in breaking strength of the noodles when bran size was 0.21 mm and 0.53 mm. Hardness, gumminess and chewiness of cooked DWCN showed a downtrend with increasing addition levels and particle size, while adhesiveness showed uptrend. The total score of DWCN showed a downtrend with increasing of addition level and particle size. For the 5% bran level, the scores of cooked DWCN were more than 83 when wheat bran particle size was 0.21 mm and 0.53 mm. By using 5–10% fine bran or using 5% medium bran in wheat flour, it is possible to satisfactorily produce fiber-rich DWCN.     

促进剂ZDiBC对硫化天然胶乳性能影响的研究

二异丁基二硫代氨基甲酸锌（ZDiBC）因其分子中二异丁胺的支化结构产生的空间位阻作用,使其与通用的未支化同类超促进剂相比在硫化过程中可显著降低N-亚硝基胺类物质的生成,是一种高效、制得硫化胶力学性能良好的环保型促进剂。而ZDiBC对硫化天然胶乳的胶体性能研究未见有报道。本研究采用硫磺为硫化剂,以ZDiBC为天然胶乳硫化促进剂,并与胶乳工业常用的二乙基二硫代氨基甲酸锌（ZDC）作对比研究,考察促进剂的用量、胶乳硫化温度和贮存时间对硫化天然胶乳粘度、机械稳定度、热稳定度的影响。结果表明：ZDiBC对硫化天然胶乳的粘度和机械稳定度的影响大于ZDC,对热稳定度的影响相差不大;随胶乳硫化温度的增加以ZDiBC和ZDC为促进剂的硫化胶乳粘度升高,而硫化胶乳机械稳定度和热稳定度则降低;随贮存时间的延长硫化胶乳的粘度增加,且ZDiBC为促进剂的硫化胶乳粘度增加幅度大于ZDC,硫化胶乳的机械稳定度略有增加而其热稳定度呈下降的趋势。     

Thermal,rheological properties and microstructure of hydrated gluten as influenced by antifreeze protein from oat (Avena sativa L.)

This study examined the thermal, rheological properties and microstructure of hydrated gluten as influenced by oat antifreeze protein (AsAFP). The thermal properties of fresh hydrated gluten, including the melting temperature, freezing temperature, freezable water content and glass transition temperature, were determined. For hydrated gluten samples after freeze-thaw treatment, the change in melting performance and freezable water content were analyzed. The results showed that the addition of AsAFP increased the glass transition temperature and decrease the melting enthalpy and freezable water content of fresh hydrated gluten. The supplementation of AsAFP also influenced the melting performance of hydrated gluten after freeze-thaw treatment. The rheological properties showed that the addition of AsAFP inhibited the deterioration of the rheological properties of hydrated gluten. The secondary structure of the gluten proteins changed significantly, α-helix decreased and β-sheet increased. The microstructure of the hydrated gluten demonstrated that supplementation with AsAFP may protect the gluten matrix from disruption during freeze-thaw cycles.     

New films based on triticale flour: Properties and effects of storage time

In this study, new films based on triticale flour were prepared by using the casting technique. Colour, microstructure, mechanical, physicochemical and water vapour barrier properties were determined. Triticale flour films were aged up to 60 days at 52% relative humidity and 25 °C. The influence of storage time on functional properties was also studied. All films presented high (from 84.01 to 85.21) lightness values (L*). Results showed that during storage the values of permeability of the films did not change significantly. Tensile strength, elastic modulus of Young and puncture force values increased and the percent of elongation at break decreased towards the last days of storage. Analysis of SEM images of films showed the appearance of small cracks at 60 days of storage. After 45 days of storage, triticale flour films maintained acceptable functional properties. In conclusion, films based on triticale flour showed properties that make them a substantial potential to be incorporated in food packaging applications.     

Fabrication and characterization of oat flour processed by different methods

The properties of oat flour can be manipulated by processing to suit various consumption and product development needs. In this work, three different processes typically used on oat flour, namely the extrusion, drum drying and enzyme-treatment spray drying process were evaluated with respect to how each process changes the quality of the oat flour. Results showed that the extrusion process produced oat flour with the best flow ability while the enzyme-treated spray drying process led to the lowest flowability. The color of enzyme-treated spray-drying oat flour was the brightest while the oat flours turned darker after extrusion and drum drying. In addition, drum dried oat flour had the highest capability to hold water. In terms of particle size distribution, the extruded and drum dried oat flour showed smaller particle size and the particle had less complete and irregular surfaces. On the other hand, the enzyme-treated spray-drying samples showed the best particle uniformity and sphericity. The viscosity of all the treated oat flour decreased with increasing shear rate, indicating the shear thinning behavior, and a weak gel-like behavior with very high viscosity was obtained via drum drying. The results reported here can be useful and provide a baseline to fully understand how the oat flour properties changes with different processing methods to offer a wider opportunity in using oat flour for food product fortification and design.