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1.
冻干水饺复水性不理想是限制其应用的主要原因,利用真空冷冻干燥技术对水饺进行了冻干实验,以复水比和感官评价为指标,研究了升华干燥温度、升华干燥时间和解吸干燥温度、解吸干燥时间以及添加剂对冻干水饺复水性和感官指标的影响。实验表明:冻干温度在-45℃,添加剂量0.35%时,冻干水饺的品质和复水性较好;并确定了较佳冻干条件:预冻温度-45℃,升华干燥阶段进行20 h后转入解吸干燥阶段,并持续6 h,此时冻干水饺复水比为1.92,感官指标为72;而添加剂为0.35%时复水比为2.68,感官指标为86。  相似文献   

2.
真空冷冻和热风干燥对蓝莓品质的影响   总被引:6,自引:0,他引:6  
研究真空冷冻干燥和热风干燥处理对蓝莓品质的影响。采用电阻法测定蓝莓的共晶点和共熔点,并绘制了蓝莓冻干曲线;从干燥后蓝莓的微观结构、复水比、色泽、质构、VC、总花色苷和总酚等指标比较真空冷冻和热风干燥蓝莓产品的品质。结果表明:蓝莓的共晶点为-33℃,共熔点为-30℃;真空冷冻干燥蓝莓复水性好,且果实中VC、总花色苷和总酚的含量分别为5.52 mg/100 g、1.55 mg/g和3.55 mg/g,显著高于热风干燥的产品。因此,真空冷冻干燥在保持蓝莓复水性、感官品质和活性成分等方面比热风干燥具有明显优势。  相似文献   

3.
猕猴桃片真空冷冻干燥工艺研究   总被引:1,自引:0,他引:1  
采用均匀实验设计,以切片厚度、解析时物料表面温度和干燥仓压力作为实验因素,以Vc损失率、叶绿素损失率和冻干时间作为冻干指标,并对猕猴桃片真空冷冻干燥过程进行优化,得到最佳工艺参数为:干燥仓压力45Pa,解析时物料表面温度44℃,切片厚度7mm,最佳工艺条件下Vc和叶绿素损失率分别为5.30%和39.30%,冻干时间为25.41h.  相似文献   

4.
该试验以香蕉和花生为原料对香蕉的护色、干燥方法及香蕉花生酱的加工工艺进行了研究。试验结果表明:香蕉去皮后,用0.2%柠檬酸 0.01%维生素C溶液浸泡10min护色、打浆,在75℃下热风干燥60min,得到香蕉粉,香蕉花生酱的最佳配方为花生酱73%、香蕉粉15%、单甘酯2%、蔗糖5%、植物油5%;香蕉花生酱适宜的杀菌条件为121℃,16min。  相似文献   

5.
为了满足我军对军用食品营养和品质的特殊需求,文中采用真空冷冻干燥技术对营养价值较高的胡萝卜进行加工,并对其冻干工艺参数进行研究。复水性能的好坏和颜色的变化是衡量冻干食品品质最重要的指标,文中研究了干燥过程中对复水性有较大影响的冷冻温度和加热温度。通过对胡萝卜冻干产品的冻干曲线,感官及复水率进行比较得出:冷冻过程决定冻干物料中的冰晶形成速度和大小,胡萝卜所需冷冻温度为—40℃左右,时间大约为2h;加热过程决定冻干物料中冰晶的升华,加热板温度设置为—20℃30min、0℃3h、20℃2 h、50℃3h4个梯度,所得产品品质最佳。  相似文献   

6.
猕猴桃果浆真空冷冻干燥工艺优化研究   总被引:5,自引:0,他引:5  
以猕猴桃果浆冻干过程中VC、叶绿素损失率和冻干时间为指标,对真空冷冻干燥过程进行优化,得到的最佳工艺参数为:物料解吸时的表面最高温度48℃,升华初始干燥仓压力26Pa,装料厚度7mm。最佳工艺条件下,VC、叶绿素的损失率预报值分别为6%和38%,冻干时间为18h。  相似文献   

7.
真空冷冻干燥对牡蛎品质的影响   总被引:1,自引:0,他引:1       下载免费PDF全文
我国牡蛎产量丰富,除部分鲜销外很多加工为干制品,然而传统牡蛎干制品复水性差、产品附加值低。为了得到高品质的牡蛎干制品,本研究对牡蛎进行真空冷冻干燥加工,并对冻干加工牡蛎的复水性、质构和蛋白、脂肪及部分滋味成分含量的变化情况进行探讨。研究结果表明:牡蛎的共晶点和共熔点温度分别为-25℃和-17.5℃,牡蛎在-30℃~-35℃条件下预冻2 h,在冷阱温度达到-40℃后在真空度20 Pa条件下干燥15 h得到干品;与对照产品(市售蚝干)相比,冻干牡蛎复水性较好,其在20 min即可复水完全,复水比为3.68;冻干牡蛎的质构也优于对照,除脂肪含量较低外,蛋白质和几种滋味成分含量也均高于对照。由此可见,真空冻干燥不仅可以减少牡蛎干制时的蛋白损失,且能够较好保持质构和原有风味,可以用于高品质牡蛎干制品的加工。  相似文献   

8.
采用真空-红外联合干燥,研究不同干燥条件下猕猴桃片干燥特性,并建立干燥数学模型。实验结果表明:猕猴桃片的真空-红外联合干燥全过程分为加速、恒速干燥和降速干燥3个阶段,而物料失水过程主要发生在恒速阶段,其水分有效扩散系数值在3.91×10-9~7.79×10-9m2/s之间,并随着红外功率、装载量和真空度的增大而增大。通过R2、χ2和RMSE等拟合优度评价指标对各种干燥模型进行评价发现,Page模型最适于描述和预测其干燥过程,该研究为开发新型猕猴桃干制品等提供技术依据。  相似文献   

9.
为研究不同干燥方法对脱水菠菜理化特性的影响。将样品分别采用热风干燥,微波干燥,真空干燥,微波-真空干燥进行干燥处理,分别测定干燥后叶绿素保存率、维生素C保存率、产品的复水性和质构特性。结果表明,微波-真空干燥脱水菠菜不仅叶绿素保存率和维生素C保存率高,产品的复水性好、质构特性好,而且干燥时间短,是一种较好的脱水菠菜制备方法。  相似文献   

10.
以新鲜牛脏器(肝、心、肚、肺)为对象,以干品率为评定指标,研究真空冷冻干燥技术对牛脏器的冻干效果,在单因素试验的基础上,采用正交优化试验对影响牛脏器冻干效果的物料厚度、真空度、干燥时间3个因子进行了优化。结果表明:各因素对干品率的影响大小顺序依次为干燥时间、真空度、物料厚度;最佳冻干参数为干燥时间20 h、真空度20 Pa、物料厚度3 mm。冻干牛脏器水分含量为6.44%,复水比为5.41,复水后牛脏器外形饱满、富有弹性,且未失去其特有的风味,可直接食用。  相似文献   

11.
不同干燥方式对香蕉产品品质的影响   总被引:1,自引:0,他引:1  
李宝玉 《食品科学》2016,37(15):100-106
为了对比普通热风干燥、真空冷冻干燥、传统油炸干燥、真空干燥、真空微波干燥、变温压差膨化干燥6种不同的干燥方式对香蕉干燥产品营养成分、微观结构、感官品质、风味成分、生产周期的影响。采用理化分析技术检测营养成分含量;扫描电子显微镜观察微观结构;固相微萃取气相色谱-质谱联用技术分析检测风味成分;评分法进行感官评价、变异系数综合评价。结果表明:6种不同干燥方式下香蕉产品营养成分变化显著,变温压差膨化干燥和真空冷冻干燥可较好保留产品各种营养成分;电子显微镜扫描显示变温压差膨化干燥产品细胞空隙最大,感官评分最高;固相微萃取气相色谱-质谱联用分析结果表明6种不同干燥方式下香蕉产品生成了不同种类风味物质和特有风味成分,变温压差膨化干燥和真空冷冻干燥能较好地保留鲜香蕉中的酯类物质。干燥方式综合评价结果为:真空冷冻干燥变温压差膨化干燥传统油炸干燥真空干燥真空微波干燥普通热风干燥。但真空冷冻干燥投资大,生产周期长;变温压差膨化干燥微观细胞结构空隙最大,赋予产品疏松多孔结构。综合考量产品营养成分、感官评分、风味物质、微观结构、生产周期五类评价指标得出,变温压差膨化干燥加工技术适用于香蕉干制品的生产加工。  相似文献   

12.
Lowbush blueberries have been processed by freeze dry, forced air, vacuum oven, and micro-convection methods to a moisture content of 16-25%. The drying effect on the product quality was evaluated. There were no significant differences in vitamin A and niacin retention except freeze dried berries had higher vitamin C retention. No significant differences occurred in retention of mineral content except higher sodium and lower magnesium were found in the micro-convection and freeze dry methods, respectively. Freeze dried and vacuum dried blueberries had higher soluble solids retention and were darker and redder than forced air or micro-convection dried berries. Freeze dried berries were found to have highest rehydration ratio and lowest bulk density.  相似文献   

13.
水果纸是新鲜水果经过打浆、熬煮和干燥后制成的脱水干果纸状薄片小吃。干燥是最古老的食品保存方法之一,可去除水果中的水分,延迟其贮藏期限供全年食用。最常见的干燥方式包括热风干燥、真空干燥、冷冻干燥及联合干燥技术。干燥过程的能源效率和水果纸的品质是水果干燥中需考虑的重要因素。本文归纳了可用于水果纸干燥的热风干燥、冷冻干燥、真空干燥、微波干燥、红外辐射干燥和折射窗干燥的研究现状以及水果纸的预处理方法和干燥工艺对其形态、质构、营养成分的影响,旨在提高水果纸的干燥效率,最大限度地保留水果的活性成分,为今后食品行业中进一步研究水果纸的干燥加工提供参考。  相似文献   

14.
Berries are dietary plants with high antioxidant activity. The aim of this study is to investigate the protective effect of berries (strawberry, grape, and blueberry) against the acrylamide (AA)‐induced general toxicity, genotoxicity, and reproductive toxicity in mice model, respectively. Mice were treated with 50 mg/kg b.w./day AA intraperitoneal injection for 5 d after feeding control diet or diet containing freeze‐dried strawberry, grape, and blueberry powder. The results showed that AA induced a significant general toxicity, genotoxicity, and reproductive toxicity in mice. Compared with the control diet, the diets containing berries could reverse the AA‐induced alterations in liver antioxidant enzymes activities (P < 0.05). Moreover, the AA‐induced genotoxicity could be prevented by the diet containing berries. The DNA damage in the lymphocyte and liver cells and the micronucleus formation in bone marrow cell were significantly alleviated (P < 0.05). Meanwhile, the mice fed with diets containing berries showed a recovery in the sperm count, the sperm activity rate, sperm motility parameters, and the abnormal sperm rate (P < 0.05). Berry powders have remarkable intervention against the AA‐induced general toxicity, genotoxicity, reproductive toxicity. Abundant phenolics, especially anthocyanins, may contribute to the intervention.  相似文献   

15.
Fresh fruits are prone to fungal contamination in the field, during harvest, transport, marketing, and with the consumer. It is important to identify fungal contaminants in fresh fruits because some moulds can grow and produce mycotoxins on these commodities while certain yeasts and moulds can cause infections or allergies. In this study, 251 fresh fruit samples including several varieties of grapes, strawberries, blueberries, raspberries, blackberries, and various citrus fruits were surface-disinfected, incubated at room temperature for up to 14 days without supplemental media, and subsequently examined for mould and yeast growth. The level of contamination (percent of contaminated items/sample) varied depending on the type of fruit. All raspberry and blackberry samples were contaminated at levels ranging from 33% to 100%, whereas 95% of the blueberry samples supported mould growth at levels between 10% and 100% of the tested berries, and 97% of strawberry samples showed fungal growth on 33-100% of tested berries. The most common moulds isolated from these commodities were Botrytis cinerea, Rhizopus (in strawberries), Alternaria, Penicillium, Cladosporium and Fusarium followed by yeasts, Trichoderma and Aureobasidium. Thirty-five percent of the grape samples tested were contaminated and supported fungal growth; the levels of contamination ranged from 9% to 80%. The most common fungi spoiling grapes were Alternaria, B. cinerea and Cladosporium. Eighty-three percent of the citrus fruit samples showed fungal growth at levels ranging from 25% to 100% of tested fruits. The most common fungi in citrus fruits were Alternaria, Cladosporium, Penicillium, Fusarium and yeasts. Less common were Trichoderma, Geotrichum and Rhizopus.  相似文献   

16.
真空冷冻干燥能够较好地保留蓝莓中花色苷、维生素等营养功能物质,但蓝莓内部水分在真空冷冻干燥过程中难以透过表皮的致密蜡质层向外扩散,进而引发结构塌陷,导致产品存在表皮皱缩、空心、汁液流失等严重缺陷,限制了真空冷冻干燥技术在蓝莓干燥领域的应用。为改善真空冷冻干燥后的蓝莓品质,研究了Na2CO3溶液浸泡时间(3、10、30min)、削皮部位(顶部、底部、顶部和底部)、打孔数目(12、14、36孔)和划痕数目(2、8、16道)对真空冷冻干燥蓝莓干燥特性、吸湿性及质构、色泽和香气等感官品质的影响。结果表明:与未预处理的真空冷冻干燥蓝莓相比,打孔和划痕预处理均可有效避免蓝莓组织塌陷和皱缩,但Na2CO3溶液浸泡和削皮处理组品质较差;打孔(36孔)和划痕(16道)处理的真空冷冻干燥蓝莓外观及其微观结构保持完整,干燥时间分别减少6h和4h,脆度分别提高31.55%和4.06%,外观及内部结构均无明显皱缩和塌陷,色泽和香气接近新鲜蓝莓。研究旨在为真空冷冻干燥技术制备高品质蓝莓整果粒提供一定的参考依据。  相似文献   

17.
Viscoelastic behaviour of dehydrated products during rehydration of apple, banana, carrot and potato was examined under uniaxial compression tests. Samples were dehydrated with four different drying methods: conventional, vacuum, freeze and osmotic-freeze drying and after that they were rehydrated in an air dryer at 50°C and 80% air humidity. Compression tests were performed during rehydration for various moisture contents, ranging from 0.01 to 1.5 kg/kg dry basis. The viscoelastic behaviour of dehydrated products during rehydration were examined comparing the values of the four parameters incorporated into the stress–strain model, during rehydration with those of dehydrated products. The four examined parameters: maximum stress, maximum strain, elastic parameter and viscoelastic exponent seem to show a hysteresis phenomenon. It can be concluded that dehydrated product do not keep their viscoelastic behaviour after rehydration due to structural damages that occur during drying. More specifically, freeze dried materials present the highest hysteresis after rehydration, losing their elasticity and becoming more viscous. Osmotic pretreatment seems to help freeze dried materials to keep their elastic nature, probably due to solids gain. Air and vacuum dried materials showed the smallest hysteresis tendency, keeping their viscoelastic characteristics during rehydration close to those of dried materials.  相似文献   

18.
张艳荣  吕呈蔚  刘通  甄佳美 《食品科学》2016,37(10):116-121
采用顶空固相微萃取结合气相色谱-质谱联用技术,分别对鲜姬松茸、热风恒温干燥、微波干燥、真空冷冻干燥3 种不同干燥方式的姬松茸中挥发性风味成分进行检测与分析。结果表明,鲜姬松茸、热风恒温干燥、微波干燥和真空冷冻干燥分别检测出20、50、43 种及22 种挥发性风味成分。热风恒温干燥新生成了醇、醛、酮、酚、醚类物质,对姬松茸风味的改良和增香具有一定作用;微波干燥生成醛类物质较多,使干燥后的姬松茸具有特殊的肉桂香气和类似苦杏仁的香味;真空冷冻干燥处理的姬松茸与鲜姬松茸在整体风味成分上较为接近,说明真空冷冻干燥方式能够较好的保持姬松茸原有风味。  相似文献   

19.
为了解不同干燥方法对印度块菌干后品质及微观结构的影响,本研究采用热风干燥、真空冷冻干燥方法对印度块菌进行处理,以感官品质(色泽、质构)、复水特性、营养成分(还原糖、总蛋白、维生素C、总黄酮)及微观结构为评价指标,评价干燥方法对印度块菌品质的影响,并利用低场核磁共振技术研究干燥处理期间水分的迁移率和分布。结果表明,与热风干燥比,真空冷冻干燥产品L*高,a*低,能够较好维持产品色泽,热风干燥产品褐变严重,且真空冷冻干燥产品硬度低,脆性高。真空冷冻干燥产品复水比及复水速率显著高于热风干燥产品(P<0.05),干燥10 min后,冷冻干燥复水比值为3.00,显著高于热风干燥(2.26)(P<0.05),冷冻干燥复水速率(0.30 min-1)显著高于热风干燥(0.22 min-1)(P<0.05)。与新鲜样品比,两种干燥产品中总蛋白含量无显著变化,维生素C、还原糖及总黄酮保留量显著降低(P<0.05);与热风干燥产品比,真空冷冻干燥产品维生素C、还原糖及总黄酮保留量显著高于热风干燥产品(P<0.05)。低场核磁共振分析表明,冷冻干燥组T23水分信号强度衰减速率高于热风干燥组,说明真空冷冻干燥效率更高。扫描电镜观察微观结构发现热风干燥产品细胞组织收缩、塌陷且结构很致密,真空冷冻干燥产品呈现多孔结构。综合分析,干燥对印度块菌干制品的营养及品质影响较大,真空冷冻干燥更适合印度块菌产品的干燥加工,本研究为提高印度块菌干制品加工品质提供理论依据。  相似文献   

20.
精选白参经过超声波提取,得到人参提取物。蓝莓经过榨汁、喷雾干燥制成蓝莓果汁粉。以人参提取物和蓝莓果汁粉为主要原料,淀粉、木糖醇等为辅料,以40%乙醇作为润湿剂,经压片而制成的一种新型口嚼片。通过单因素和正交试验,确定最佳工艺条件和配方。结果表明,人参提取物添加量为15%、蓝莓果汁粉添加量35%、淀粉添加量为20%、40%乙醇添加量为40%。  相似文献   

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