提取方法对挤压文冠果油品质和贮藏变化的影响

研究不同提取方法对挤压过的文冠果仁中提取的油脂理化性质和提取率的影响,以及贮藏过程中酸价、MDA的变化。研究表明超声波辅助浸提法为文冠果油提取的最佳方法,其提取条件为:文冠果经挤压处理后,以石油醚为提取溶剂,超声波处理1.5 h(温度65℃)后在85℃浸提6.5 h。提取的文冠果油品质较好,且宜贮藏。     

Glass transition and state diagram for freeze-dried Agaricus bisporus

Sorption isotherms and state diagram of freeze-dried Agaricus bisporus were developed to further investigate the connection between the two distinct criteria of food stability. Sorption isotherms of freeze-dried A. bisporus were determined by the gravimetric method and the data were modeled by GAB model. The GAB monolayer moisture content was calculated to be 6.2 g/100 g (d.b.). The glass transition temperature of freeze-dried A. bisporus was determined by differential scanning calorimetry. The state diagram was composed of the freezing curve and glass transition line, which were fitted according to Clausius–Clapeyron model and Gordon–Taylor model, respectively. The state diagram yielded maximally-freeze-concentrated solutes at 0.704 solids with the characteristic temperature of glass formation being −77.9 °C. The state diagram and sorption isotherms of freeze-dried A. bisporus are useful in evaluating the storage stability as a function of temperature and moisture content as well as optimizing drying and freezing conditions.     

牛至精油微胶囊的制备、表征及在杏贮藏期的抑菌效果

为进一步开发植物精油在果蔬采后抑菌保鲜中的应用,本实验以牛至精油为芯材,以明胶、阿拉伯胶为壁材,采用复凝聚法,通过工艺优化制备了牛至精油微胶囊,并通过扫描电子显微镜、傅里叶变换红外光谱、热重分析和差示扫描量热分析进一步表征了其理化特性和缓释性能,最后评估了不同施用剂量的牛至精油微胶囊在杏果实采后贮藏中的抑菌效果及其对腐烂率和抗病相关酶活力的影响。结果表明：牛至精油微胶囊制备最优工艺条件为芯材和壁材质量比1∶1、壁材质量比（明胶、阿拉伯胶质量比）1∶1、反应温度45 ℃、反应时间30 min,在此工艺条件下制备的牛至精油微胶囊包埋率为83.65%,载油率为74.36%,平均粒径为147 μm;与单一牛至精油（纯度为98%）相比,牛至精油微胶囊具有更好的球形和规则表面结构,保持了更高的热稳定性,并具备了缓释特性;其中,4%（以果实质量计）的牛至精油微胶囊处理降低了杏果实在贮藏期间的菌落总数、霉菌总数和腐烂率,并提高了杏果实贮藏期间过氧化物酶、L-苯丙氨酸氨解酶、β-1,3-葡聚糖酶、过氧化氢酶和几丁质酶活性,降低了杏果实贮藏期内的多酚氧化酶活性。该结果为开发基于植物精油的缓释抑菌剂提供了新思路。     

高温、高湿和光照对特殊医用配方食品流变特性的影响

为确定特殊医用配方食品在高温、高湿、光照条件下的流变性变化,以豌豆肽为原料进行影响因素(高温、高湿、光照)试验、加速试验、长期试验,揭示环境因素对特殊医用配方食品黏性、弹性与流变性质的影响。特殊医用配方食品在高温下5 d之后食用安全性降低;在高湿条件下放置10 d左右的医用食品,其食用安全性相对于放置5 d左右的医用食品安全性要高;在光照条件下5 d之后食用安全性降低。由此可见,温度、湿度、光照对特殊医用配方的食用有很大影响。在加速试验及长期试验中,医用食品最佳保质期时间应控制在2~5个月。文章为具有广阔发展前景的特殊医用食品的开发、食用条件及储存条件提供理论数据和指导依据。     

Differentiation of Spanish paprika from Protected Designation of Origin based on color measurements and pattern recognition

A method based on the measurement of color is proposed to differentiate paprika samples from different geographical origin. ASTA scale and coordinates in the CIELAB color space were obtained from UV–Vis spectra of acetone extracts of samples. Samples of sweet, hot/sweet and hot paprika from the two recognized Spanish Protected Designation of Origin, Murcia and Extremadura, were analyzed. Two strategies were considered with the aim of building classification models. The first used the computed color parameters as input data, whilst the second used the scores of the samples obtained after applying principal component analysis to reduce the dimensionality of the data matrix from the absorbance spectrum. The developed pattern recognition models were based on linear discriminant analysis, support vector machines and multilayer perceptron artificial neural networks. In both considered strategies, the best results were obtained in the case of artificial neural networks, with classification efficiencies ranging from 92% to 95% for the different varieties of paprika.     

Recycling of coal fly ash for fabrication of elongated mullite rod bonded porous SiC ceramic membrane and its application in filtration

Mullite bonded SiC ceramic membranes were synthesized by a facile solid-state reaction process, using SiC, solid waste fly ash as raw materials and MoO₃ as catalyst for growth of mullite at 1000 °C. The effect of MoO₃ catalyst on mullitization reaction and mullite morphology was investigated. Different pore formers were used to enhance the porosity and to observe its effects on the permeability parameters and filtration characteristics. At room temperature Darcian (k₁) and non-Darcian (k₂) in both water and air flow were measured and clean water flux was determined. The porous SiC ceramics with addition of 5 wt.% MoO₃ exhibited a flexural strength of 38.4 MPa at porosity 36.4 vol% and showed 92% oil removal efficiency from oily wastewater. This technique, combining low-cost materials and the co-sintering at low temperature, can serve as a cost-effective method for the production of high-performance porous SiC ceramic membrnaes for filtration application.     

挤压参数对酱油渣粗纤维含量影响研究

采用挤压膨化技术对酱油渣进行预处理,研究挤压工艺参数对酱油渣中粗纤维含量的影响。在单因素试验的基础上,以挤出物粗纤维含量为考察指标,以含水量、挤压温度、螺杆转速为挤压参数,运用中心组合试验设计（CCD）对挤压酱油渣中挤压参数进行优化。结果表明,最佳挤压膨化参数为含水量32%,挤压温度为100 ℃,螺杆转速为95 r/min。在此优化条件下,挤出物粗纤维含量为19.5%,与挤压膨化前原料相比,粗纤维含量降低了31.3%。该挤压膨化技术可以提高酱油渣的利用率。     

南美白对虾肉玻璃化转变温度测定的影响因素

为准确测定南美白对虾肉的玻璃化转变温度(Tg),对影响其Tg测定的因素(包括差示扫描量热仪(DSC)测定过程中程序扫描次数、退火温度和时间、加热速率、样品湿基含水率)进行了系统研究。结果表明,含非冻结水的虾肉宜采用单扫描程序。含冻结水的虾肉冰晶体出现始、末对应的温度范围为-22℃~-53℃,在此温度范围内退火30 min,焓变ΔH先降低后增加,当ΔH达到最小值171.1 J/g时,与之对应的温度为-35℃,即为虾肉适宜的退火温度。虾肉Tg随退火时间的延长而降低,且在超过30 min后逐渐趋于稳定,因此适宜退火时间为30 min。虾肉Tg随升温速率的降低而降低,并在速率低于5℃/min后逐渐趋于恒定,适宜升温速率范围5℃/min。Tg随虾肉含水率的增加而降低,含水率25.88%时,Tg降低趋势明显;而含水率25.88%时,Tg降低幅度很小并逐渐趋于恒定。本研究结果可为南美白对虾肉DSC扫描程序的确定提供理论依据。     

黑果腺肋花楸多酚对抑郁症小鼠肠道菌群及大脑BDNF水平作用机理的探讨

该研究探讨了黑果腺肋花楸（黑果）果实、叶子的多酚调节抑郁小鼠模型的作用机理,旨在通过饮食干预达到调节抑郁的目的。注射4 mg/mL皮质酮构建小鼠抑郁症模型,采用行为实验、16S rRNA基因测序技术等对小鼠行为、肠道菌群组成与脑源性神经营养因子（brain-derived neurotrophic factor,BDNF）的变化规律等进行研究。研究表明黑果多酚提取物可以显著改善抑郁症小鼠游泳、糖水偏好等行为,可将肠道菌群多样性水平升高至18.23%;使得大脑中BDNF水平可提高81.39%。黑果多酚提取物通过调控肠道菌群、大脑BDNF途径影响抑郁小鼠行为,改善抑郁状态,从而发挥抑郁调节作用,为黑果宽渠道深度开发提供了新支撑,高值化应用提供了理论指导,为饮食调理抑郁症提供新资源,也丰富了功能性食品类型和理论。     

响应面法优化甘油酯转甲酯化条件

在反应温度、反应时间和甲醇钠用量3个单因素实验基础上,利用响应面分析法,以交酯化后样品中甘油和VE含量为评价指标,对甘油酯转甲酯化最佳条件进行了研究。结果表明,最佳反应温度73.7℃、反应时间2.1 h、甲醇钠用量0.51%(W/W)。在最佳条件下,VE保存率为90.5%,酯化率为89.4%。