云南小粒种咖啡热风干燥特性及其数学模型

以云南小粒种咖啡为原料,探究小粒种咖啡热风干燥特性及最佳数学模型,为咖啡热风干燥工艺提供参考。对小粒种咖啡湿豆进行热风干燥,用正交试验的方法研究其在不同热风温度、风速、铺装厚度和搅拌转速下的热风干燥特性,比较10种数学模型在热风干燥特性中的适用性。结果表明：热风风速在干燥实验中对传热传质有催进作用;搅拌可加快热传递提高热效率,减少干燥时间;铺装厚度主要影响干燥用时,铺装厚度与干燥速率变化成反比;咖啡干燥以降速干燥为主,无明显恒速干燥阶段,热风温度对热风干燥的干燥特性影响最大;对正交试验进行极差、方差分析可知,温度40℃,风速1 m/s,搅拌转速2 r/min为最优热风干燥方案,最佳数学模型为Logarithmic模型,热风温度、热风风速与搅拌转速3个因素对热风干燥总时长影响的极差值为19、6.67、5.5,3个因素在95%置信区间下P值为0.011、0.082、0.391。主次顺序为热风温度A>热风风速B>搅拌转速C;由评价指标R²、SSE、残差均方及对比实验数据与常用干燥模型进行非线性回归拟合分析,结果显示Logarithmic模型拟合度最好,其中R²为0.986444、SSE为0.021734、残差均方为0.002075。该数学模型可预测云南小粒种咖啡湿豆的热风干燥特性曲线,也为实际的生产与加工提供依据和参考。     

油莎豆主要营养成分及生理功能研究进展

油莎豆（Cyperus esculentus L.）,又称虎坚果,沙草科莎草属多年生草本植物。油莎豆具有适应性广、生长期短、生物量大、含油量高等优势特性。油莎豆茎叶可做青贮饲料,块茎可生吃或熟吃,此外,油莎豆还可用来榨油,榨油后的油饼可用来做饲料。因此油莎豆作为一种集粮、油、牧、饲于一体的新兴农作物,具有较高的经济价值和开发潜力。为了深入了解油莎豆,促进油莎豆资源的高值化利用和研究,本文综述了油莎豆中油脂、蛋白和多糖等主要营养成分的研究进展,详细阐述了油莎豆降血脂、降血糖、抗氧化和保肝等生理功能,并就其市场规模和科学研究前景进行了展望。     

不同热风干燥温度对高良姜片品质特性的影响

为明确热风干燥温度对高良姜片品质特性的影响,以高良姜为原料,分别对60、70、80、90 ℃条件下干燥获得的高良姜片的干燥时间、色泽、总酚、总黄酮和挥发性成分进行了比较分析.结果表明:高良姜片的干燥时间随温度升高而减小,60℃时干燥时间为29h,90℃时缩短为11h;高良姜片L*值随温度的升高而增大,a*值和b*值则整...     

香草兰豆荚不同干燥方法的比较研究

对热风干燥和冷冻干燥处理香草兰样品的干燥效果进行比较,结果表明热风干燥的干燥速率随温度的增加而增加,冷冻干燥的干燥速率介于40和50℃热风干燥的速率之间。电子鼻分析结果表明,与40、50和60℃热风干燥相比,相同干燥时间条件下,冷冻干燥能更好的保留香草兰原有风味,同时冷冻干燥处理的香草兰样品具有更强的香气强度。     

绿茶低温真空与热风联合干燥新工艺研究

为提高烘干绿茶的品质,特别是保证得到绿茶绿润的干茶色泽,对绿茶的干燥工艺进行了探索.对揉捻后的绿茶采用低温真空与热风联合干燥,以传统的热风干燥和真空冷冻干燥为对照,对不同干燥方法绿茶中叶绿素、茶多酚、氨基酸等有效成分保留程度、绿茶感官品质以及能耗等指标进行综合评价.结果表明:联合干燥工艺绿茶的外形、香气、叶底得分均比传统热风干燥的高,特别是在外形色泽上有明显优势;同时,其综合品质也高于冷冻真空干燥工艺的品质;联合干燥工艺能耗介于热风干燥与冷冻真空干燥之间.     

糖厂滤泥薄层干燥特性实验研究

采用薄层干燥方式研究糖厂滤泥的热风干燥特性。在标准隧道式热风干燥实验装置上通过改变热风温度、流速以及滤泥滤饼的厚度进行实验,测定滤泥的失水变化,获得干燥曲线。结果表明,滤泥滤饼厚度、热风温度和热风流速均对干燥速率有重要影响。其中滤饼厚度对干燥速率影响最大;高温高速有利于提高干燥速率,但是会降低恒速干燥的临界含水分,风速对临界含水分影响不大。最适热风温度和风速分别为90℃和8m/s。滤泥在热风温度为90℃、流速为8m/s,滤饼厚度为4mm进行干燥时,其临界含水量约为干基含水量0.33。     

不同品种花生热风干燥干后品质研究

为探究品种对花生干燥后品质变化的影响，本试验以高油酸型、高糖型和普通型花生为原料，在相同的干燥条件下研究其热风干燥干后综合品质(蛋白质、脂肪、氨基酸、脂肪酸、生育酚、硬度)和挥发性成分并分析比较不同品种间的差异。结果表明，不同品种花生干燥后各品质指标存在差异。其中，高油酸和高糖花生的粗脂肪含量存在显著性差异(P<0.05)。高油酸花生的必需氨基酸含量最高，普通花生次之，高糖花生最低。不同品种花生干燥后棕榈酸、硬脂酸、油酸、亚油酸、花生酸和山嵛酸百分含量均存在显著性差异(P<0.05)。高油酸花生和普通花生的油酸含量最高，高糖花生的亚油酸含量最高，二者含量成反比。不同品种花生中均检测出3种生育酚，高糖花生的总V_E含量显著高于普通花生和高油酸花生(P<0.05)。此外，共检测出12类81种挥发性物质，高糖花生和高油酸花生主要为醇类和烷类，普通花生主要为烷类和烯烃类。干燥过程中随着干基含水率的降低，花生壳的硬度均呈现先降低后升高的趋势，花生仁的硬度均呈现增大—减小—增大的趋势。本研究探明了不同品种花生干燥后的品质特征，为适用于不同品种花生干燥条件的选择...     

绿茶低温真空与热风联合干燥新工艺研究

为提高烘干绿茶的品质,特别是保证得到绿茶绿润的干茶色泽,对绿茶的干燥工艺进行了探索。对揉捻后的绿茶采用低温真空与热风联合干燥,以传统的热风干燥和真空冷冻干燥为对照,对不同干燥方法绿茶中叶绿素、茶多酚、氨基酸等有效成分保留程度、绿茶感官品质以及能耗等指标进行综合评价。结果表明:联合干燥工艺绿茶的外形、香气、叶底得分均比传统热风干燥的高,特别是在外形色泽上有明显优势;同时,其综合品质也高于冷冻真空干燥工艺的品质;联合干燥工艺能耗介于热风干燥与冷冻真空干燥之间。     

不同品种蓝莓干的品质比较及干燥方式的选择

以采摘自河源蓝莓种植基地的7个蓝莓品种为试材,对其采用热泵干燥的方式进行干燥处理,测定干燥前后样品的品质特性,包括可溶性糖含量、Vc含量、花青素含量以及多酚含量;比较干燥后品种之间的差异以及干燥前后的变化,以及测定了干燥后花青素对DPPH·自由基的清除能力;基于这些品质特性进行系统聚类分析,选出适合干燥的蓝莓品种,再对该品种的蓝莓进行3种不同方式的干燥,包括热泵干燥、热风干燥和真空干燥,同样进行上述品质特性测定及比较,对3种干燥方式进行简单评价。结果表明：园蓝是较适合用于干燥的蓝莓品种,真空干燥对蓝莓的营养成分有较好的保留。     

花生果微波-热风耦合干燥特性及能耗分析

为提高花生果干燥后的品质，采用脉冲间歇式-低强度微波、高强度微波以及高&低强度微波分别与热风 进行耦合干燥，研究不同干燥工艺下花生果的干燥特性、品质特性及干燥能耗情况。结果表明：采用脉冲间歇式- 高&低强度微波热风耦合的干燥工艺最佳，其中微波强度 0.95 W/g照射时间 16.7 min，微波强度 0.48 W/g照射时间 11.7 min，干燥总耗时198.3 min，可将花生果含水率从50.0%降至15.5%，并且其总能耗比低强度微波和高强度微波 分别降低了37.1%、8.6%，干燥后花生果的品质较佳。因此，脉冲间歇式-高&低强度微波热风耦合干燥工艺的研究 对花生果的减损具有重要意义。     

微波真空干燥对铁皮石斛品质特性影响的研究

本研究以新鲜铁皮石斛为原料,采用微波真空干燥方法干燥,通过测定铁皮石斛的多糖含量、色泽、多酚氧化酶（PPO）、水分分布状态、组成氨基酸以及多酚的DPPH?和?OH清除率,研究微波真空干燥对铁皮石斛品质特性的影响。结果表明：相比于新鲜样品,当微波强度为9 W/g,干燥后样品的多糖含量最高可达52.21%;氨基酸分析仪分析结果表明,微波真空干燥后铁皮石斛的总游离氨基酸和风味氨基酸含量显著提高。在微波强度9 、12 、15 W/g下,微波真空干燥的铁皮石斛的PPO活性分别在干燥16、12、6 min后不再存在,表明微波真空干燥能够在较短时间内钝化铁皮石斛的PPO活性,且微波强度越大时间越短。干燥过程的非酶促褐变主要由Maillard反应引起。低场核磁共振结果表明,自由水驰豫时间T₂₃和A₂₃均显著降低。自由基清除能力研究结果表明,铁皮石斛多酚仍具有较强的羟基自由基清除能力。通过观察干燥后样品的微观结构发现,随着微波功率密度的增大,样品孔状结构受到更严重破坏,微波强度越大,铁皮石斛的复水特性越好。     

Side-effects of botanical insecticides derived from Meliaceae on coccinellid predators of the date palm scale

Bioassays were conducted in Mauritania to determine the toxicity of botanical insecticides from the tree Melia volkensii Gürke (Meliaceae) to ladybird predators (Coleoptera: Coccinellidae) of the date palm scale, Parlatoria planchardi Targ. (Homoptera: Diaspididae). M. volkensii seed extract was formulated in neem oil or a mixture of neem and maize oil. Three preparations were tested on Chilocorus bipustulatus L. var. iranensis, an introduced species, and one on the indigenous Pharoscymnus anchorago F., a species already used in previous bioassays. Fourth instar larvae were exposed for 2 days to treated scale-infested date palm leaves. The botanical insecticides were toxic to C. bipustulatus. Median lethal application rates (LR₅₀s) were close to the recommended application rate of 1 l/ha. In contrast, P. anchorago showed no increased mortality at this rate. Hazard quotients (application rate divided by the LR₅₀) were generally less than 2, suggesting a low risk for both species. However, risk mitigation measures are recommended when using oil formulations because the threshold value for C. bipustulatus, the more susceptible of the two ladybird species, would be exceeded at higher dose rates or when conducting multiple applications. Sublethal effects included an extension of the larval stage and morphogenetic defects. These effects were again more pronounced in C. bipustulatus than in P. anchorago.     

荔枝果实干制加工的热烫和无硫护色工艺

荔枝是我国南方一种重要的热带、亚热带水果,具有较高的营养价值和商业潜力.然而,在高温高湿季节,采后荔枝果实极易发生腐烂变质、果皮褐变、病原菌侵染等品质劣变现象.因此,荔枝果实除鲜食外,常被加工成不同的商业产品,特别是荔枝果干.干制荔枝由于干制加工时间较长,易发生果皮褐变,导致其外观色泽、产品质量和风味丧失,最终限制荔枝...     

Effect of blanching and drying methods on the nutritional and sensory quality of leafy vegetables

The nutrient retention and sensory quality factors of vegetables blanched by two methods and solar-dried or dried in the cabinet dryer were evaluated. The type and conditions of the blanching treatment prior to drying affect the retention of ascorbic acid, carotene, and ash in the dried vegetables. The sun-dried vegetables had inferior colour, texture and accpetibility compared to the vegetables dried in the cabinet dryer. There were significant differences in the rehydration and drying ratio of the dried vegetables. The implications of the blanching and drying processes for an effective preservation technique are discussed.     

天然橡胶微波干燥动力学模型研究

利用本课题组设计发明的微波干燥湿天然橡胶物料设备,对微生物凝固湿天然橡胶进行物料表面温度分别为358、373、388、403 K的微波干燥试验,干燥时间均为15 min,每4 s获取一组干燥过程相关数据,测试分析湿天然橡胶(微生物凝固)的微波干燥失水特性,并建立湿天然橡胶微波干燥动力学模型.结果表明,干燥温度越高,湿天然橡胶含水率下降越快;快速干燥阶段为物料干燥的主要失水阶段;湿天然橡胶微波干燥动力学模型可由多项式模型来表示.     

气调干制对龙眼肉干燥速度及干制品品质的影响

用CO2,N2气体置换干燥室空气作为干燥介质,采用自行研制的小型气调干燥机实验设备对龙眼肉的干燥进行对比实验,探讨了气调干制对龙眼肉干燥速度及干制品品质的影响。结果表明:龙眼肉采用气调干制,可显著提高干制品的Vc保存率和还原糖质量分数;在气体的O2含量降低状态下,充N2气体气调干燥具有较高的干燥速度,制品质量最好,复水率最高。      

Possible alternative utilization of Cynara spp.: II. Chemical characterization of their grain oil

The grain oils extracted from six genotypes of Cynara species: two globe artichokes (Cynara scolymus L.), two cultivated cardoons (C. cardunculus L. var. altilis DC.) and two wild cardoons (C. cardunculus L. var. sylvestris Lam.), were analysed in order to ascertain their alimentary value. Oil yield, moisture, acidity, peroxide number, UV spectrophotometry and CIE colour parameters, fatty acids, phytosterols and -tocopherol were determined by standard methods. Cynara species which are most promising in terms of quality and quantity of oil were the cardoons, especially those belonging to the wild cardoon genotypes. Triacylglycerols were the dominant constituents together with very little amounts of phospholipids and glycolipids. The high content of oleic and linoleic acids in a balanced ratio, and the low amount of free acids, peroxides, saturated and linolenic acids ensure a good alimentary quality. Distribution of phytosterols was typical of oil from grain of Asteraceae such as sunflower and safflower. Moreover the optimal -tocopherol content offers a guarantee of stability against oxidation.     

Degradation of Carotenoids in Apricot (Prunus armeniaca L.) During Drying Process

Carotenoids are natural compounds whose nutritional importance comes from the provitamin A activity of some of them and their protection against several serious human disorders. The degradation of carotenoids was investigated during apricot drying by microwave and convective hot-air at 60 and 70 °C. Seven carotenoids were identified: antheraxanthin, lutein, zeaxanthin, β-cryptoxanthin, 13-cis-β-carotene, all-trans-β-carotene and 9-cis-β-carotene; among these, all-trans-β-carotene was found to be about 50 % of total carotenoids. First-order kinetic models were found to better describe all-trans-β-carotene reduction during drying, with a degradation rate constant (k₁) that increased two folds when temperatures increased by 10 °C, in both methods. No differences were found in k₁ between apricots dried by hot air at 70 °C (k₁?=?0.0340 h^?1) and by microwave at 60 °C. The evolution of total carotenoids (117.1 mg/kg on dry basis) during drying highlighted a wider decrease (about 50 %) when microwave heating was employed, for both set temperatures. Antheraxantin was found to be the carotenoid most susceptible to heat, disappearing at 6 h during both trials with microwave as well as during convective hot-air at 70 °C. For this reason, antheraxanthin could be a useful marker for the evaluation of thermal damage due to the drying process. Also the degree of isomerization of all-trans-β-carotene could be a useful marker for the evaluation of the drying process.     

变温压差膨化技术制取花生裹衣食品的研究

以糖、面粉、米粉和变性淀粉为复配料,采用变温压差膨化技术制备花生休闲食品。通过改变膨化温度、抽空时间、抽空温度、膨化压力和停滞时间等因素,考察各因素对花生休闲食品质量品质的影响,确定了变温压差膨化的最佳工艺条件:膨化温度为100℃;膨化压力差为0.2 Mpa;停滞时间为10min;抽空温度为80℃;抽空时间为150min。结果表明,采用以上工艺条件生产的花生膨化产品的硬度比超市花生豆明显降低了69.04%,脆度增加了52.21%,酥脆可口,营养味美。