渗透方式对真空冷冻干燥芒果细胞结构及品质的影响

为探索渗透方式对冻干芒果细胞结构及品质的影响,本实验以玉芒为原料,在环境温度（20、30 ℃）下采用蔗糖固态渗透（SSD）、液态渗透（LOD）方式处理芒果后再进行真空冷冻干燥,通过测定渗透方式处理后芒果鲜样可溶性固形物、细胞形态以及分析冻干芒果的弹性模量、孔隙度、细胞壁结构、色泽以及V_C、总酚、β-胡萝卜素保留率指标的变化。结果表明:固态渗透芒果可溶性固形物增加量高于液态渗透,液态渗透处理的芒果细胞形态与鲜样（CK）无明显差异,固态渗透随蔗糖添加量的增加可溶性固形物含量和细胞形态皱缩程度增加;固态渗透减少细胞间孔隙度提高芒果弹性模量;傅里叶变换红外光谱结果表明O-H的伸缩震动吸收峰,随着蔗糖添加量的增加,吸收峰强度逐渐增加;低蔗糖固态渗透有利于维持芒果色泽;在环境温度20和30 ℃条件下固态渗透处理的真空冷冻芒果V_C和总酚的保留率高于液态渗透,其中固态渗透SSD20的V_C和总酚保留率最高分别为37.75%、33.37%;固态渗透SSD20处理的真空冷冻芒果的β-胡萝卜素保留率高于液态渗透LOD30,但固态渗透随蔗糖添加量的增加,β-胡萝卜素的保留率逐渐下降。本研究结果发现低蔗糖固态渗透可以有效提高真空冷冻芒果的综合品质,为改善芒果干燥制品品质提供理论参考。     

不同渗透方式对芒果脱水效率和品质的影响

为了比较在夏季（30 ℃）和冬季（20 ℃）生产环境下不同渗透方式在芒果脱水效率和品质上的差异,本文以失水率、固增率、水分有效扩散系数、可溶性固形物扩散系数、V_C和总酚保留率以及三态水转化为考察指标,探究固态渗透（SSD）和液态渗透（LOD）对糖渍芒果脱水效率和品质的影响。结果表明,固态渗透的脱水效率以及营养物质保留率高于液态渗透;在糖渍48 h后,在环境温度20 ℃下SSD40（蔗糖:芒果(w/w)=4:10）的失水率和固增率最大为49%和5.11%,SSD20（蔗糖:芒果(w/w)=2:10）的V_C和总酚保留率最高为47.43%和43.66%;在环境温度30 ℃下,SSD40的失水率和固增率最大为57.41%和6.36%,SSD20的V_C、总酚保留率最高为43.79%和42.43%。渗透过程改变了芒果样品中水的结合状态,自由度高的水分向自由度低的方向迁移。本文研究结果将为果干类产品固态渗透预处理技术的应用提供理论参考。     

超声辅助不同小分子糖渗透处理后真空冷冻干燥油柑的品质比较

该研究评价了超声辅助五种小分子糖渗透处理后冻干油柑的理化特性及体外抗氧化活性。结果表明：相比对照组,经超声辅助渗糖处理的油柑水分损失率、固形物增加率升高;冻干油柑内部孔隙更加致密,硬度显著提高、脆度基本保持,复水性下降;低聚异麦芽糖处理组的吸湿率（18.25%）低于对照组（22.54%）;葡萄糖和麦芽糖处理组的冻干油柑色差ΔE小,分别为2.73和1.71,即颜色保留率高;低聚麦芽糖和蔗糖对冻干油柑的风味强化效果较好;蔗糖、葡萄糖和麦芽糖处理组的冻干油柑可滴定酸含量较低;与对照组玻璃化转变温度（Tg=43.66 ℃）相比,麦芽糖处理组的Tg 升高到45.53 ℃,其他处理组则显著降低了样品的Tg ;除木糖醇处理组（9.44 mg/g）外,不同超声渗糖处理组的总酚保留率均较高;蔗糖和低聚异麦芽糖渗透处理可有效保持冻干油柑的体外抗氧化能力。总的来说,超声辅助蔗糖和低异聚麦芽糖渗透处理的冻干油柑品质较好,其中低异聚麦芽糖可作为一种蔗糖替代品用于开发功能性冻干油柑。     

超声辅助渗透处理对冷冻干燥双孢蘑菇冻干效率和品质的影响

为了在生产高品质冷冻干燥产品的同时进一步降低干燥过程中的能耗与成本,选取双孢蘑菇为研究对象,以冷冻和冷冻干燥过程中双孢蘑菇的共晶点、共熔点、冻干温度及冻干产品的质构、微观结构、色泽和营养品质为考察指标,研究普通渗透和超声辅助渗透处理对冷冻干燥双孢蘑菇冻干效率和品质的影响。结果表明,与新鲜样品相比,经超声辅助渗透处理45 min后,样品冷冻时间和冷冻干燥时间分别缩短了21.24%和28.62%,并且其冻干产品的可滴定酸、总蛋白质以及多酚等营养物质的保留率高于普通渗透120 min处理组。此外,与普通渗透120 min处理组相比,超声辅助渗透45 min处理组冻干样品复水比、硬度更高,其微观结构更加接近于未经渗透处理的冻干样品。     

富硒纳豆芽孢杆菌发酵鹰嘴豆风味物质和活性成分研究

为了评价富硒纳豆芽孢杆菌发酵鹰嘴豆风味和活性成分,本文主要研究了富硒纳豆芽孢杆菌固态和液态发酵鹰嘴豆所产生的挥发性物质、游离氨基酸及其他活性物质组成和含量。结果表明,纳豆芽孢杆菌液态发酵鹰嘴豆（L-SD1）的主要挥发性成分是2 -甲基丁酸和3 -甲基丁酸,纳豆芽孢杆菌固态发酵鹰嘴豆（G-SD1）、富硒纳豆芽孢杆菌液态发酵（L-Se-SD1）及固态发酵鹰嘴豆（G-Se-SD1）的最主要挥发性成分均为2,5-二甲基吡嗪。液态发酵比固态发酵所产生的挥发性物质种类较多,富硒对主要挥发性物质的种类和相对含量影响较大（p<0.05）。采用氨基酸自动分析仪法检测出L-SD1、L-Se-SD1、G-SD1和G-Se-SD1中均含有16种氨基酸,包括7种人体必需氨基酸和9种其他氨基酸,且苦味氨基酸含量均最高。不同发酵方式对氨基酸种类影响无差异;液态发酵比固态发酵产生的总游离氨基酸含量高。富硒纳豆芽孢杆菌液态发酵鹰嘴豆总黄酮含量为(1.91±0.02）mg/mL,维生素K2含量为(755.7±0.11）μg/100g,卵磷脂含量为(2.41±0.03）%,相比于未富硒组,分别提高了80.2%,81.6%,10.6%。本研究有利于对鹰嘴豆纳豆的营养成分和风味物质进行评估。     

不同渗透方式对芒果脱水效率和品质的影响

糖渍是一种高效的食品预脱水方法,有关糖液浸渍法(液态渗透)已有大量研究,而关于固体糖干法糖渍(固态渗透)研究较少.为了比较这两种渗透方式的差异,利用菲克方程进行传质动力学分析以及相关指标测定,研究固态渗透和液态渗透对糖渍芒果脱水效率和品质的影响.结果表明:固态渗透SSD30处理组(m(蔗糖):m(芒果)=3:10)与液...     

发酵方法对普洱茶茶褐素样品组成的影响

采用水提醇沉法从塔宾曲霉液态发酵普洱茶粉和传统固态发酵工艺所产普洱熟茶中提取茶褐素。应用居里点热裂解气相色谱-质谱联用技术及比色法研究液态发酵茶褐素样品和固态发酵茶褐素样品的化学组分。结果显示,液态发酵样品中的茶褐素、总多酚、总黄酮、总儿茶素和氨基酸显著高于固态发酵样品（P＜0.05）;液态发酵样品中的总糖、多糖、茶黄素显著低于固态发酵样品（P＜0.05）;液态发酵样品与固态发酵样品的蛋白质含量差异不显著（P＞0.05）。在不同居里点热裂解温度下,固态发酵样品与液态发酵样品的裂解产物分别有12?种（380?℃）和9?种共同成分（600?℃）,两者在不同温度下的裂解产物中,酚类种类最多,含量最高的化合物是咖啡因。     

预冻及蔗糖浸渍方法对冻干苹果片品质的影响

[目的]探究真空冻结和常压冻结两种预冻方法以及预冻前浸渍蔗糖、冻干中间浸渍蔗糖两种浸渍方法对冻干苹果片品质的影响。[方法]将冻干工艺分为无蔗糖浸渍真空预冻（VFFD）、无蔗糖浸渍常压预冻（CFFD）、蔗糖前浸渍真空预冻（BSVFFD）、蔗糖中间浸渍真空预冻（MSVFFD）、蔗糖前浸渍常压预冻（BSCFFD）和蔗糖中间浸渍常压预冻（MSCFFD）6组,分析各组苹果片冻干样品的主要品质指标。[结果]MSVFFD组样品色泽ΔL^*相对较低,Δa^*和ΔE相对较高,更偏深红色;蔗糖浸渍显著提高了冻干样品的产出率,其中MSVFFD组和MSCFFD组的最高,BSVFFD组和BSCFFD组的次之,未浸糖对照组的最低（P<0.05）;蔗糖浸渍显著降低了冻干样品的形变率,浸糖处理组的形变率未见显著差异,但显著低于未浸糖的对照组（P<0.05）;蔗糖浸渍显著提高了冻干样品的穿刺硬度和做功,其中MSVFFD组的最高,未浸糖的对照组的最低,真空冻结组硬度高于常压冻结组,中间浸渍组硬度高于前浸渍组（P<0.05）;MSVFFD组和MSCFFD组的吸湿率最低,CFFD组的吸湿率明显高于其他组（P<0.05）。[结论]真空冻结和中间浸糖方法更有助于改善冻干苹果片品质,其中MSVFFD组赋予冻干产品较佳的综合品质。     

樱桃番茄渗透预处理热风干燥特性研究

为了提高干制品的营养保留率和品质,进行了渗透预处理联合热风干燥的工艺路线的实验研究。以樱桃番茄为例,分别对不同浓度(50%,70%)蔗糖溶液常压渗透以及真空渗透处理后热风干燥的干燥时间、干燥速率、样品体积比、Vc保留率、硬度、颜色等参数分别进行测定和比较。结果表明:渗透预处理可以除去新鲜樱桃番茄中的大部分自由水,从而减少其热风干燥时间,使产品在高温中的暴露时间减少,从而缩短整体干制时间、提高干制效率及营养品质。经渗透预处理的樱桃番茄干制产品的体积比和Vc保留率要比直接热风干燥的产品增加,而硬度大大下降;其中经浓度为50蔗糖溶液真空渗透预处理后干燥产品的体积比、Vc保留率以及硬度是直接70℃热风干燥的1.72、2.26和0.12倍;而且产品的色泽更加接近新鲜原料,使产品的口感和感官品质更好。研究表明,渗透预处理联合热风干燥是1种很有发展前景的制干工艺。     

Everzol ED深三原色活性染料环保特性

探讨了Everzol ED深三原色环保活性染料染色织物的浮色可洗性、洗涤液色度及总COD值,并对其节水节能减排效率进行评价.结果表明,与常规MCT/MCT及VS/MCT活性染料相比,该染料具有高效节能降耗减排特性,可实现节水、节能约40%,节约染料60%,节省促染盐20%～30%;可减少染色车间的排污量约40%,染后织物洗涤液的总COD值及色度可分别降低60%.     

不同组合渗透与冷冻前处理对蓝莓干燥品质的影响

为研究渗透、冷冻前处理对食品干燥品质的影响,同时为改善产品品质提供理论支撑和技术指导,以蓝莓为研究对象,在对样品进行相同干燥处理(热风,30 h,60℃)前,进行不同组合模式的渗透(海藻糖、氯化钙、蔗糖)和冷冻-解冻(液氮-80℃,室温)前处理,以干果的脱水速率、含水量、色泽、质构、总糖、抗氧化活性物质等作为评价指标进...     

Headspace volatile compounds during osmotic dehydration of strawberries (cv Camarosa): Influence of osmotic solution composition and processing time

The influence of the type of sugar in the osmotic solution and of the time of processing on the volatile compounds of strawberries was studied, in order to optimize the technique as a pre-treatment to further processing. Strawberries of cultivar ‘Camarosa’, cut into 1 cm thick slices, were subjected to osmotic dehydration at 30 °C for 1, 2, 4 and 6 h using either 60% (w/w) sucrose or 60% (w/w) sorbitol solutions. Volatile compounds of fresh and processed strawberry slices were analyzed by static headspace—gas chromatography. Osmotic treatments provoked a loss in volatile compounds due to the migration, mainly of esters, into the osmotic media. The variations in the volatile pattern depended on both time of treatment and type of osmotic solution. The greater changes occurred after 2 h in sucrose; with a promotion of fermentative volatiles (acetaldehyde, ethyl acetate), and a decrease in the other volatiles. Using sorbitol as osmotic agent, the major variations in the volatile pattern occurred after 4 h of osmosis, and the fermentative process was less important than in sucrose, as sorbitol could be less effective in forming a peripheral layer at the fruit surface and/in reducing tissue porosity.     

超声辅助糖液渗透处理对真空冷冻干燥桃脆片干制品品质及吸湿性的影响

为探究超声辅助糖液渗透处理对真空冷冻干燥桃脆片干制品品质及吸湿性的影响,本实验比较了白桃经4 种糖液（蔗糖、麦芽糖、葡萄糖、低聚异麦芽糖）超声辅助渗透处理后桃片的水分损失率、固形物增加率以及真空冷冻干燥后桃脆片的微观结构、质构特性（硬度、脆度）、吸湿性及玻璃化转变温度。结果表明：与对照组相比,经超声辅助糖液渗透处理的桃片水分损失率、固形物增加率提升,孔隙更加致密且细胞组织发生破裂和结构坍塌,硬度显著提高（P＜0.05）;且超声辅助糖液渗透处理可以降低桃脆片的吸湿性,在相对湿度从0梯度增加到90%的过程中,各处理组样品最终达到吸湿平衡时的质量变化率范围为55.16%～59.63%,对照组为61.43%;与对照组玻璃化转变温度（52.37 ℃）相比,超声辅助麦芽糖渗透脱水处理使桃脆片体系的玻璃化转变温度升高到64.27 ℃。综上,超声辅助糖液渗透处理对桃脆片品质产生影响的同时,也对降低桃脆片吸湿性和改变桃脆片体系玻璃化转变温度具有重要影响,本研究可为改善和提升白桃干制品品质提供技术参考。     

OSMOTIC DEHYDRATION OF MUSKMELON (CUCUMIS MELO): INFLUENCE OF BLANCHING AND SYRUP CONCENTRATION

The influence of blanching and syrup concentration on the quality parameters of osmo‐air‐dried muskmelon product was investigated. Fruit samples were dehydrated with sucrose solutions at 40, 50 and 60°Brix and the resulting products were analyzed for browning degree, ascorbic acid (AA) concentration and water activity. The values for all three parameters decreased as the syrup concentration increased. Blanching treatment before the osmotic processing had no effect on browning but caused a decrease in AA concentration. Osmotically dehydrated fruits showed no browning increase for at least 4 weeks at 2C. A decrease of about 60% in AA concentration was observed within the first 2 weeks at 10C. In contrast, AA loss was only observed after 2 weeks at 2C. The influence of storage time and temperature on AA retention was investigated by 2² factorial design. Statistical analysis of results showed that the two factors have a significant effect on AA retention. Osmotic dehydration may be an interesting alternative for processing of muskmelon as a pretreatment followed by cold storage or drying.     

Osmotic concentration of potato.

A study was conducted to determine what conditions define the equilibrium state between potato and osmosis solution for an osmosis concentration process. It was shown that at equilibrium, there is an equality of water activity and soluble solids concentration in the potato and in the osmosis solution. Rinsing the surface of the potato after osmotic concentration was shown to significantly reduce solids gain and soluble solids concentration in the potato, thus resulting in a sizeable increase in the potato water activity.
When water loss, solids gain, change of water activity and economics are considered, the optimal conditions for an equilibrium osmosis with sucrose would use a 50% solution at a solution/solids ratio of 4. Uptake of solids during sucrose-based osmosis results in 75% of the soluble solids in the equilibrated potato coming from the osmosis solution. A comparison of various osmosis solutions at a 60% total solids level shows that mixed sucrose-salt solutions give a greater decrease of water activity than the pure sucrose solution, even though the mass transport data are similar, this undoubtedly being due to the uptake of salt.
A model has been developed for calculation of osmosis mass transport data and water activity for osmotic concentration to equilibrium in sucrose solutions for the concentration range 10–70% and solutionlsolids range of 1–10. The mass transport data can be calculated with an average error < 4%. Water activity can also be predicted with good accuracy for the range of parameters normal for osmosis concentration processes. The proposed model was also able to predict osmosis mass transport data and water activity data for short, non-equilibrium osmosis times.     

超声渗透脱水-热风干燥梨的研究

超声波的空化效应及机械效应可有效增强脱水过程中物料内外的质量传递速率,因此超声波技术可用于果蔬渗透脱水的强化,而超声渗透脱水又常作为其他干燥方式的预处理以提高脱水速率。本研究以砀山梨梨片为实验材料,进行超声波渗透脱水预处理联合热风干燥研究。结果表明：提高超声功率及渗透液糖度可显著增加失重率;与直接热风干燥相比,单一的渗透脱水预处理延长总脱水时间约30～60 min;而超声渗透脱水预处理可缩短热风干燥的干燥时间40～120 min,并提高有效水分扩散系数11%～56%。因此,在热风干燥前进行超声渗透脱水预处理,可有效缩短总工艺时间,提高干燥效率。     

Rehydration and sorption properties of osmotically pretreated freeze-dried strawberries

The aim of this work was to investigate the influence of osmotic dehydration and type of osmotic solution on selected physical properties of freeze-dried strawberries. Frozen Senga Sengana strawberries were dehydrated in osmotic solution with water activity of about 0.9 (sucrose and glucose solutions and starch syrup). Osmotically dehydrated fruits were frozen and freeze-dried at heating shelf temperature of 30 °C for 24 h.