特色香蕉类型‘美食蕉’品种果肉中淀粉与矿物质在后熟期的变化

目的：以新选育的抗枯萎病特色香蕉栽培类型‘美食蕉’（Plantain）品种（‘美食蕉1号’、‘美食蕉2号’）为研究对象,比较其与鲜食香蕉栽培类型‘香牙蕉’（Cavendish）品种（‘中蕉8号’）在后熟期间果肉中淀粉质量分数和矿物质含量的变化,以期为美食蕉品种资源的利用提供参考。方法：采用比色卡和色差仪进行成熟度分析,通过抗性淀粉质量分数测定和光学显微镜观察进行淀粉物理性质的研究,此外,使用发射光谱仪测定果肉矿物质元素含量。结果：催熟前‘美食蕉1号’和‘美食蕉2号’抗性淀粉质量分数占总淀粉质量分数比例均比‘中蕉8号’高26%左右,三者分别为74.99%、75.23%、48.64%;后熟过程中,三者的总淀粉和抗性淀粉质量分数均随着催熟时间的延长而降低;‘美食蕉1号’和‘美食蕉2号’的香蕉粉颗粒均呈长椭圆形,‘中蕉8号’的香蕉粉颗粒多呈不规则状,后熟期间3 种香蕉粉的颗粒数目逐渐减少;催熟后,‘美食蕉1号’和‘美食蕉2号’的果肉硬度比‘中蕉8号’大,其果皮炭疽病斑的形成也较晚;‘中蕉8号’果肉中的K含量高于‘美食蕉1号’和‘美食蕉2号’,然而‘美食蕉’果肉在后熟期可较多地保留K元素。结论：‘美食蕉’在香蕉深加工和健康食品开发方面具有更广阔的应用前景。     

UHT Milk Processing—Effect on Process Energy Requirements

Energy requirements for processing milk using a free falling film steam infusion ultra-high temperature (UHT) sterilization process and a high temperature-short time (HTST) pasteurization process were determined and compared. Product flow rate was 2500 kg/hr. Milk to milk regeneration was used with both processes. UHT process temperatures were 138, 143, 149, and 154°C. The energy requirements for the UHT and HTST processes ranged between 573 and 667 kJ/kg milk and 217 and 228 kJ/kg milk, respectively. Although the UHT process consumed between 345 and 450 W/kg milk additional energy in the plant, the UHT sterilization of milk has been estimated to result in a net energy savings of 547 - 652 kJ/kg milk because the product does not require post-processing refrigeration.     

预处理对红薯丁变温压差膨化干燥的影响

研究糖渍、冷冻、水分3种不同预处理方式对红薯丁变温压差膨化干燥产品含水率、色泽、膨化度、硬度和脆度的影响。结果表明,适当程度的糖渍预处理使物料加速失水,对物料色泽和外形的保持有显著的作用;低温预处理有利于膨化干燥产品膨化度、硬度和脆度的提高;适度的水分含量有利于产品膨化度和色泽品质的提高。     

不同预处理方式对苹果片真空冻结特性的影响

为了解预处理对苹果真空冻结过程特性的影响,采用冻融、热烫、超声波与未预处理4种预处理措施,进行苹果片真空冻结试验,分析各组在失水率、温度、组织内水分状态以及细胞结构等方面的差异。结果表明:4组苹果片40 min真空冻结失水率分别为46.48、27.49、24.80和22.92%,冻融组失水率明显高于其他3组(p0.05),热烫组与未处理组也有显著性差异(p0.05),超声组与未处理组无显著差异(p0.05);苹果片真空冻结过程分为降压闪发段、冰晶生成段和深层冻结段3个阶段,4组冻结终温依次为-30.40℃、-27.42℃、-26.84℃与-26.50℃;冻融和热烫处理使苹果片LF-NMR自由水横向弛豫时间T23峰位向左明显偏移,组织内自由水束缚力增强;冻融和热烫预处理对真空冻结前、后的苹果片细胞组织结构形态的破坏影响程度均高于其他2组;4组物料真空冻结特性所表现出来的差异性主要是由于物料组织结构产生不同程度破坏影响所致。     

Effect of Pretreatments on Quality Characteristics of Dehydrated Ivy Gourd (Coccinia indica L.)

Ivy gourd (Coccinia indica L.) is an important tropical vegetable cultivated in India. It belongs to the Cucurbitaceae family and is attributed with neutraceutical properties such as hypoglycemic effect and contained a fair amount of ascorbic acid. The effect of blanching and different pretreatments on the quality characteristics of dehydrated ivy gourd slices was optimized. The treated ivy gourd slices were dehydrated in a cross flow hot air drier at 50 ± 1 °C to a final moisture content of 4.6%. The dehydration ratio of dried ivy gourd slices ranged from 17.1:1 to 18.7:1. Ivy gourd slices blanched at 98 °C in water, dipped in 0.2% potassium metabisulphite (K₂S₂O₅) solution and dried at 50 ± 1 °C for 5–6 h resulted in best product. Dehydrated ivy gourd slices obtained from the optimized treatment had good color, texture with rehydration ratio of 1:8.6. Equilibrium relative humidity of dehydrated slices was 34.18% with an initial moisture content of 4.6% at 28 ± 1 °C. Dehydrated slices were packed in low density polyethylene (LDPE) and metallized polyester polyethylene (MPP) pouches and stored at room temperature (27–35 °C) for 6 months. The dehydrated slices were analyzed for changes in physicochemical composition and sensory quality characteristic such as color and appearance, texture and overall quality during storage. Dehydrated ivy gourd slices remained acceptable during storage of 4 and 6 months in LDPE and MPP pouches, respectively, at room temperature.     

预处理对热风干燥番茄粉理化性质的影响研究

考察预处理方法对不同温度下热风干燥番茄粉理化性质的影响。预处理方法包括醇滤、水滤和糊精助滤,并以无任何添加物直接过滤的样品作对照。样品经预处理后,置于一定温度下强制对流干燥至规定含水量,粉碎后得番茄粉,分别测定所得番茄粉的番茄红素含量、堆密度、分散时间、复水比、吸湿性和颜色。实验结果表明,番茄粉的理化性质与预处理方法有密切关系,醇滤预处理所得番茄粉的品质最好,其次是水滤,而糊精助滤与直滤相差不大。在65℃下干燥时,醇滤样品的番茄红素含量是直滤样品的1.43倍,提高了176.34μg/g;堆密度从0.44g/mL降低到0.33g/mL,分散时间由52s减小至23s,复水比由原来的7.6倍增加到10.3倍,吸湿性由1.9%增加至3.1%;粉末L*值由48.13增加至53.55。证明醇滤预处理可明显提高番茄粉中番茄红素的含量,减小其堆密度和分散时间,增大复水比和吸湿性,且番茄粉的颜色更加亮丽。     

Foam-Mat Drying of Plantain and Cooking Banana (<Emphasis Type="Italic">Musa</Emphasis> spp.)

Foaming, reconstitution, and sensory attributes of foam-mat-dried plantain and cooking banana were investigated. Plantain and cooking banana pastes mixed with different concentrations (0.005%, 0.01%, 0.015%, and 0.02%) of glyceryl monostearate (GMS) were whipped, and the resulting foams were air dried at 60°C, 70°C, and 80°C. Physical, chemical, and sensory properties of fresh and reconstituted paste from plantain and cooking bananas were determined. Higher GMS concentration and longer whipping time resulted in lower foam densities. Generally, cooking banana foams showed lower foam density compared to plantain foam. Lower drying temperatures and concentration of GMS resulted in longer drying time. pH (4.41–4.80), titratable acidity (0.06–0.08), and water absorption capacity (56.75–64.02%) of the reconstituted pastes varied with commodity, drying temperature, and %GMS concentration. Fresh and reconstituted pastes showed comparable physical and chemical attributes, while the taste and sensory attributes of fresh plantain and cooking banana pastes were significantly (p < 0.05) better than those of reconstituted pastes.     

微波干燥温度分布对胡萝卜干燥特性与品质的影响

为提升胡萝卜的干燥品质,减少局部过热和过分干燥问题,采用多物理场仿真与微波干燥试验,研究胡萝卜微波干燥中旋转运动与不同微波缓苏时间对温度分布、干燥特性、品质（色差、复水比、VC含量、感官评价）的影响。结果表明：水分比的模拟值与试验值的RMSE<5%,模型有效模拟了胡萝卜微波干燥热质传递的过程。旋转样品的温度均匀度指标λ较不旋转减至0.092,干制品品质及其均匀性显著提高,其中色差值标准差减到0.18。R1/4（旋转条件下加热20 s缓苏60 s）条件下胡萝卜样品温度分布区间为65～75℃,色差、VC含量均为最优。采用旋转与1/4的缓苏时间的干燥条件较优。本研究成果为胡萝卜微波干燥应用提供理论参考依据。     

雪莲果热泵干燥特性及品质研究

研究雪莲果样品厚度、装料量、干燥温度、风速和旁通比对雪莲果热泵干燥特性及质量变化的影响。结果表明：雪莲果干燥速率随着样品厚度和装料量的增加而降低,随着干燥温度和风速的升高而增加。雪莲果热泵干燥过程绝大部分以降速干燥为主伴随相对较短时间的恒速干燥,而有些干燥速率曲线只存在降速干燥阶段。综合考虑单位能耗除湿率、色泽差异、收缩率、复水比,雪莲果热泵干燥最适参数范围：样品厚度2～4 mm、装料量1～2 kg/m2、干燥温度25～35 ℃、风速1.5～2.0 m/s。而旁通比对雪莲果热泵干燥进程影响不显著。     

预处理对压差闪蒸干燥丰水梨脆片品质及微观结构的影响

为研究预处理方式对丰水梨压差闪蒸干燥的影响,以丰水梨为原料,探讨热烫预处理、深冻预处理、柠檬酸浸渍预处理和果葡糖浆浸渍预处理对丰水梨干燥产品色泽、硬度、脆度、复水性、感官、可溶性固形物含量、可滴定酸含量、总糖含量、总酚含量、总黄酮含量、抗坏血酸含量和微观结构等的影响。结果表明：适当的热烫预处理有利于干燥产品感官品质的提高;深冻预处理虽有助于产品总酚和抗坏血酸的保留,但其硬度较小,膨化效果不明显;柠檬酸浸渍预处理的硬度较大,可滴定酸含量最高,口感偏酸,感官评价喜好度为中等;果葡糖浆浸渍预处理有助于增加干燥产品可溶性固形物和总糖含量,但其硬度较大,脆度较小,失去商品性质。综合比较,热烫处理是丰水梨压差闪蒸干燥较适宜的预处理方式。     

干燥方法对速食薏米粉干燥特性与品质的影响

采用微波干燥(MD)、微波对流干燥(MCD)、热风干燥(HAD)和传统烤制法(TR)4种干燥方法对高压汽蒸熟制薏米进行干燥制备速食薏米粉,考察4种干燥方法对薏米的干燥特性,并比较其对薏米粉色泽、营养成分、冲调特性和感官评价的影响。结果表明:在干燥特性方面,MCD所用时间最短,仅为26 min,其次为TR,为35 min,HAD所用时间最长,为90 min,且MCD的平均干燥速率最高。在色泽方面,选用MCD方法处理的样品颜色偏黄,更接近于新鲜薏米粉的色泽。在营养化学组分特性方面,干燥后的薏米粉中灰分、粗脂肪、蛋白质、总糖和还原糖的含量均有损失,其中MD对灰分和总糖损失最少;MCD对蛋白质和还原糖的保留最好;TR干燥后的粗脂肪含量最高为7.02 g/100 g。冲调特性方面,MCD制备的产品堆积密度最低,休止角最小,流动性最好,水合能力最高;TR制备的薏米粉的润湿下沉性和分散性时间最短,结块率和吸湿率最低。MCD 样品获得最高的感官评价分84.8分。综合评价相对HAD和TR,MCD干燥速率快、品质好。     

固定床热风干燥模式对荔枝干制特性的影响

采用固定物料位置固定热端(模式I)、变换物料位置固定热端(模式II)和固定物料位置变换热端(模式III)三种模式对荔枝果实进行固定床热风多阶段干燥,分别测定了不同物料层(A、B和C三层)物料的热风风速、温度、水分含量、干燥速率、有效扩散系数(Deff)和体积收缩率。结果表明,不同的干燥层物料的热风和温度分布不均匀。经过四阶段共26 h干燥,模式I、II和III中整体样品的水分含量分别为45.70%、42.07%和41.18%。模式I中A层物料的终水分含量为28.44%,显著低于B层和C层样品(p<0.05),Deff为1.48×10-6m2/s,显著大于B层和C层物料(p<0.05)。模式II各层间物料终水分含量和Deff差异不显著(p>0.05),干燥较均匀。模式III中A层物料的终湿基含水量和Deff与B、C层的物料的相比差异不显著(p>0.05),干燥较均匀,可实现简约操作和规模加工。     

干燥温度及氧气含量对胡萝卜气调干燥特性的影响

为探讨干燥温度及氧气含量对胡萝卜气调干燥特性的影响,进行氮气气调热风干燥实验研究。结果表明：提高干燥温度可显著缩短干燥时间;当氧气含量由20.9%降至5%,对流传质系数维持不变,而对流传热系数约增大0.5%;胡萝卜素含量随着氧气含量及干燥温度的下降而升高,氧气含量低至5%可有效减缓干燥过程中胡萝卜素的氧化降解;在40～60 ℃区间,5%及10%氧气含量条件下的总色差（ΔE）值要明显低于15%及20.9%氧气含量条件下的ΔE值,表明低氧气调热风干燥可有效保护产品色泽。因此,采用气调干燥技术有利于获得高品质的胡萝卜干燥产品。     

热风干燥和远红外干燥对草莓粉品质特性的影响

采用热风干燥和远红外干燥分别在不同温度（60、70、80 ℃）处理草莓,并对6 种草莓粉中水分含量、维生素C含量、花青素含量、多酚含量、抗氧化活性、风味物质等品质特性进行测定分析。结果表明：热风干燥60 ℃和70 ℃时所得草莓粉水分含量较低,维生素C、花青素和多酚含量较高,其中热风干燥60 ℃时草莓粉DPPH 自由基清除率较高。草莓粉中的风味物质类型主要有醇类、醛类、酮类、酸类、酯类和烃类等,其相对含量在不同的干燥方式下随温度变化也不相同。6 种草莓粉经聚类分析,在欧氏距离为10 时,可分为3 类,第一类是热风干燥60 ℃,第二类是远红外干燥70 ℃,第三类是热风干燥70 ℃、热风干燥80 ℃、远红外干燥80 ℃和远红外干燥60 ℃。综上所述,热风干燥60 ℃时所得草莓粉品质特性较佳,在实际生产中可根据具体情况选择合适的干燥方式和干燥温度。