雪莲果超声波辅助渗透脱水工艺参数的优化

以渗透脱水温度、时间、蔗糖质量分数、超声波功率和处理时间为因素,以失水率(water loss,WL)和固形物增加率(sugar gain,SG)为指标,通过单因素试验,研究雪莲果的渗透脱水工艺参数。以渗透脱水温度、时间、蔗糖质量分数、超声波处理时间为因素,以WL、SG和二者比值(WL/SG)为指标,通过二次回归正交旋转组合试验设计建立雪莲果超声波辅助渗透脱水过程中各响应值(WL、SG和WL/SG)与各因素之间的回归方程,并得到超声波辅助渗透脱水的最优工艺参数。结果表明,超声波辅助处理可显著提高雪莲果渗透脱水效果;影响WL的因素主次顺序是温度＞时间＞蔗糖质量分数＞超声波处理时间;影响SG的因素主次顺序依次是渗透脱水时间＞超声波处理时间＞温度＞蔗糖质量分数;影响SG/WL的因素主次顺序是渗透脱水时间＞蔗糖质量分数＞超声波处理时间＞温度。雪莲果超声波辅助渗透脱水的最佳工艺参数为渗透脱水温度41℃、时间1.7h、蔗糖质量分数60.18%、超声波处理时间35min。在此组合参数条件下,SG/WL平均值为0.059。     

超声波强化菠萝渗透脱水工艺

研究超声波强化菠萝渗透脱水的工艺过程。结果表明超声波强化菠萝渗透脱水的优化工艺条件：超声波频率中(48.1kHz)、超声波功率300W、糖液质量分数60%、糖液温度60℃、超声波作用时间40min,在此工艺条件下菠萝脱水率可达到41.41%。超声波强化技术能提高菠萝渗透脱水过程中的传质速率,缩短脱水时间。     

黑加仑整果微波辅助渗透脱水工艺研究

为解决微波膨化过程中黑加仑果含水率过高易爆裂、口感酸涩等问题,提出微波辅助渗透脱水新工艺。运用响应曲面法,研究微波功率、白利度、微波作用次数和渗透时间对失水率、固形物增加率和膨化率的影响,优化出黑加仑整果微波辅助渗透脱水工艺:微波功率800 W、白利度70°Brix、微波作用次数4次、渗透时间8 h,此时可得到43.67%的失水率、13.00%的固形物增加率和126.92%的膨化率。渗透过程中白利度、渗透时间、微波作用次数增加,失水率、固形物增加率和膨化率随之增加。微波功率增加,失水率、固形物增加率和膨化率先减小后增加。研究结果可以为表皮渗透性差的小浆果整果的渗透脱水工艺提供参考。     

低糖紫薯果脯微波真空渗糖工艺优化

以紫薯为试材研究微波渗糖过程中微波功率、微波处理时间、真空度、液料比和明胶添加量对低糖紫薯果脯渗糖效果的影响。以果脯中还原糖含量为指标,采用响应面法对微波真空渗糖工艺进行优化。结果表明:经冷冻预处理紫薯,以液料比71(g/g)在混合糖液(糖液组成为质量分数20%麦芽糖与20%蔗糖,以355的质量比混合,明胶质量分数1%)中进行微波渗糖,微波功率560 W、渗糖时间7 min和真空度0.05 MPa。在该条件下制得的紫薯果脯中还原糖含量达3.60 mg/g,花色苷保留率达93%,品质较好。     

黑莓渗糖过程中水分和溶质扩散的数学模型

以黑莓-白糖固液体系为研究对象,研究了黑莓在不同条件糖溶液中的渗透脱水规律,得出了渗糖过程中水分和溶质扩散的数学模型。渗透液的质量分数选取40%、50%、60%,溶液的温度选取30、40、50℃,糖溶液和黑莓的质量比为10∶1,渗透脱水时间为0~5 h。利用AZUARA等提出的双组分系统数学模型得到了每种实验条件下黑莓样品最终渗透平衡状态时的失水率和固形物增加率,结果表明,在一定实验条件范围内,黑莓脱水率和固形物增加率均随渗透液浓度、渗透时间和溶液温度的增大而增大;同时使用菲克第二定律估算了每种试验条件下水分和糖的有效扩散系数,上述渗透条件下水分和糖的有效扩散系数分别在1.77×10~(-9)~2.10×10~(-9)m~2/s和1.36×10~(-9)~1.60×10~(-9)m~2/s范围内。     

超声波辅助提取紫薯多糖工艺优化的研究

为了研究超声波辅助提取紫薯多糖的最佳工艺,在超声波频率60Hz下,考察超声波功率、提取温度、提取时间、液料比等4个单因素对紫薯多糖得率影响的基础上,采用响应面分析法对紫薯多糖的超声波辅助提取工艺进行优化。结果表明,紫薯多糖超声波辅助提取的最佳工艺条件为:超声波功率270W、提取温度44℃、提取时间84min、液料比46:1(m L/g),在此条件下,多糖得率为8.45%~8.75%,与理论预测值一致。与传统热水浸提法、超高压辅助提取法相比,采用超声波法的紫薯多糖得率分别提高了341.03%和46.01%。这表明,超声波辅助提取工艺可以有效地提取紫薯多糖。     

超声波法提取紫薯茎叶中总黄酮的工艺优化

以紫薯茎叶为实验材料,采用超声波辅助溶剂法提取其中的总黄酮,考察液料比、提取时间、提取温度、超声功率和乙醇体积分数对紫薯茎叶中总黄酮得率的影响。基于单因素实验,选取四个主要影响因素液料比、超声时间、超声功率、乙醇浓度,应用Box-Behnken响应面实验设计法优化工艺条件。研究表明,紫薯茎叶中总黄酮的最佳提取工艺条件是:液料比18:1 (mL/g)、提取时间50 min、超声功率200 W、乙醇体积分数75%,总黄酮实际得率为3.46%,与预测值3.51%相接近,研究结果为总黄酮的高效提取及紫薯茎叶的综合利用提供了参考。     

樱桃番茄真空渗透预脱水工艺优化

以苏龙一号樱桃番茄作为试材,通过比较烫漂划线、针刺、划线、超声波预处理方法,确定了烫漂划线作为真空渗透预脱水的预处理方法。在该基础上,运用单因素试验研究了真空度、糖液浓度、渗透温度、渗透时间对樱桃番茄渗透预脱水效果的影响,进而确定真空度为0.080MPa,并应用响应曲面法优化其它参数,得出樱桃番茄真空渗透预脱水的最佳工艺条件为:糖度50°Brix、温度53.37℃、时间4.88h,该条件下樱桃番茄失水率与固形物增加率比值最大,为7.24。     

响应面法优化紫薯花色苷超声波辅助提取工艺及其稳定性研究

以紫薯为原料、酸化乙醇为提取剂,超声波辅助提取紫薯中植物化学物花色苷。在单因素基础上采用响应面法优化紫薯花色苷提取工艺条件,结果表明:超声波辅助提取紫薯花色苷最优工艺条件为:超声波功率270 W、超声波时间40 min、液料比29:1 mL/g、乙醇浓度64%,在此条件下花色苷含量为0.356 mg/g。稳定性试验研究表明:紫薯花色苷不耐高温,在光照、碱性、抗坏血酸等条件下稳定性较差,但在葡萄糖溶液中稳定性较高。     

微波超声波组合提取猴头菇多糖工艺优化及其抗氧化活性

通过单因素试验分别考察粉碎粒度、料液体积质量比、提取温度、提取时间、微波功率和超声波功率对猴头菇多糖提取得率的影响,确定各因素的适宜水平。在单因素试验基础上,应用Box-Behnken试验设计和响应面分析法,探讨料液体积质量比、提取温度、提取时间和超声波功率对提取猴头菇多糖得率的影响。响应面优化结果表明,微波超声波组合提取猴头菇多糖的最优工艺为:粉碎粒度20目、液料体积质量比20 mL/g、提取温度74℃、提取时间16 min、微波功率200 W、超声波功率1 052 W。在最优工艺条件下,多糖得率为6.44%,非常接近预测值,说明所以优化的提取工艺参数可靠。体外抗氧化活性结果表明,微波超声波组合提取的猴头菇多糖抗氧化活性较高,对羟基自由基、DPPH自由基和超氧阴离子自由基清除作用显著,可以作为一种良好的天然抗氧化剂。     

莴笋渗透脱水有效扩散系数研究

以葡萄糖溶液浓度(10%～40%)和温度(35～65℃)为影响因素,研究了莴笋渗透脱水的动力学过程。分别使用Azuara模型和Fick第二扩散定律计算出了平衡时刻的失水率、固形物增加率以及相应的水分和固形物有效扩散系数。设计了均匀实验,通过曲面拟合的方法得到了水分、固形物有效扩散系数与因素的回归方程。结果表明:失水率随着葡萄糖溶液浓度增加而增大,但随着温度的升高而降低;固形物增加率随着溶液浓度和温度的增加而增加。Azuara模型可用来预测失水率和固形物增加率,通过曲面拟合得到的有效扩散系数回归方程拟合性较高。有效扩散系数反映了失水率和固形物增加率达到平衡时刻的快慢程度。     

Evaluation of Mass Exchange During Osmotic Dehydration of Plum Using Response Surface Methodology

Water loss (WL), solid gain (SG), weight reduction (WR) and shrinkage were quantitatively investigated during osmotic dehydration of plum using response surface methodology with the sucrose concentration (30–60g/100 g sample), temperature of sucrose solution (40–60°C) and immersion time (60–240 min). Experiments were designed according to Central Composite Rotatable Design with these three factors. For each response, second order polynomial models were developed using multiple linear regression analysis. With respect to water loss, solid gain, weight reduction and shrinkage, both linear and quadratic effects of four variables were found to be significant. In most cases, an increase of sucrose concentration, temperature and immersion time increased WL, SG, WR and shrinkage, except the increasing of immersion time for osmotic treatment has no effect on shrinkage. It was found that immersion time and temperature were the most significant factors affecting the WL during osmotic dehydration of plum followed by concentration of sucrose solution. This was also true for WR. Effect of temperature and time were more pronounced for SG than the concentration of sucrose solution.     

Optimisation of osmotic dehydration of carrot cubes in sucrose-salt solutions using response surface methodology

Osmotic dehydration of carrot cubes in ternary solution of water, sucrose and sodium chloride at different solution concentrations, temperatures and process durations were analysed for water loss and solute gain during osmotic dehydration. The osmotically pre-treated carrot cubes were further dehydrated in a cabinet dryer at 65 °C and were then rehydrated in water at ambient temperature of water for 10–12 h and were analysed for rehydration ratio, shrinkage and overall acceptability after rehydration. The process was optimised for maximum water loss, rehydration ratio and overall acceptability of the rehydrated product, and for minimum solute gain and shrinkage of rehydrated product by response surface methodology. The optimum conditions of various process parameters are 50°B+10% w/v aqueous sodium chloride concentration, 46.5 °C solution temperature and 180 min process duration.     

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。     

Evaluation of Factors Influencing Microwave Osmotic Dehydration of Apples Under Continuous Flow Medium Spray (MWODS) Conditions

Microwave osmotic dehydration under continuous flow medium spray (MWODS) conditions is an innovative concept with high potential for enhancing moisture loss as well as improving product quality. Quantification of mass transfer kinetics under different processing conditions is important for managing and optimizing the osmotic dehydration process. A response surface methodology was used for evaluating and quantifying the moisture loss and solids gain kinetics of apples during the MWODS process. Experiments were designed according to a central composite rotatable design with all independent variables included at five levels (sucrose concentration, 33.3–66.8°Brix; medium temperature, 33.3–66.8 °C; medium flow rate, 2,120–3,480 ml/min; and medium contact time, 5–55 min). The process responses were moisture loss (ML), solids gain (SG), and weight reduction (WR) and were related to process variables using second-order polynomial regression models. The lack of fit was not significant (p?>?0.05) for any of the developed models. For ML, SG, and WR, the medium contact time was the most significant factor during the MWODS process followed by medium temperature and sucrose concentration. The effect of medium flow rate was only significant with moisture loss and weight reduction. The quantity of ML, SG, or WR achieved over a 30 min treatment time was chosen as the drying rate. These rates were shown to be responsive to the osmotic treatments increasing with sucrose concentration, medium flow rate, and medium temperature.     

OPTIMIZATION OF OSMOTIC DEHYDRATION PROCESS OF CARROT CUBES IN SUCROSE SOLUTION

ABSTRACT

For optimization of the osmotic dehydration process of carrot cubes in sucrose solution by response surface methodology (RSM), the experiments were conducted according to face‐centered central composite design. The independent process variables for the osmotic dehydration process were osmotic solution concentrations (45–55°Brix), temperature (35–55C) and process durations (120–240 min). Statistical analysis of results showed that all the process variables had a significant effect on all the responses at 5% level of significance (P < 0.05). The osmotic dehydration process was optimized by RSM for maximum water loss, rehydration ratio, retention of color, sensory score and minimum solute gain. The optimum process conditions were 52.5°Brix sucrose syrup concentration, 49C osmotic solution temperature and 150‐min process duration.

PRACTICAL APPLICATIONS

The process of osmotic dehydration can be used for the preparation of shelf‐stable products for the purpose of use during off‐season. The quality of preosmosed carrots is much superior to the product dehydrated with the convectional method of convective dehydration. The osmotically dehydrated carrots can be used for cooking as vegetables after rehydration or can be added directly into soups, stews or casseroles before cooking. If the product is blanched before osmotic dehydration, the process can be used successfully for the preparation of carrot candy.     

Acceleration of mass transfer rates in osmotic dehydration of elephant foot yam (Amorphophallus paeoniifolius) applying pulsed-microwave-vacuum

The elephant foot yam slices were processed with combined pulsed-microwave-vacuum osmotic drying. Osmotic dehydration at ambient (28 °C and 45% RH) was carried out using different levels of sucrose concentration (30, 40, 50 and 60% w/w), salt concentration (5, 7.5, 10 and 12.5% w/w) and dehydration time (10, 20, 30, 50, 70, 90 and 120 min). During the osmotic dehydration, pulsed microwave vacuum (15 kPa pressure, 1 W/g power density and 1.853 pulsating ratio) was maintained for 2 min over the sample and solution to enhance the mass transfer. For this purpose, the osmotic dehydration experiments were conducted in the microwave-vacuum cavity. Azuara model predicted the moisture loss and solid gain by elephant foot yam slices during osmosis. It was observed that both the moisture loss and the solid gain increased with increasing concentration of the osmotic solution. The optimum conditions found in the process were 40% w/w sucrose concentration, 6% w/w salt concentration and 70 min osmotic dehydration time, resulting in to 42.80% moisture loss (initial weight) and 14.65% solid gain (initial weight). Further, samples were dried using microwave vacuum dryer up to moisture content of 5–6% d.b. by varying microwave power density (2, 4, 6 and 8 W/g) and pulsating ratio (1.312, 1.625, 1.983 and 2.250). Page model was fitted to the data to study the microwave vacuum drying kinetics. The microwave vacuum drying at 1.625 pulsating ratio with microwave power density 4 W/g yielded a product with the highest overall acceptability score. Guggenheim, Anderson and deBoer (GAB) model was used in the study of the sorption behavior of dehydrated elephant foot yam and shelf life prediction.Industrial relevanceThe production of elephant foot yam in India and South East Asia is comparatively higher than other vegetables. Although, it is nutritious product and good source of energy, food industries are not interested to process elephant foot yam using a time consuming traditional osmotic dehydration process followed by hot air drying. Therefore, present research work was undertaken from industry suggestion to develop accelerated osmotic dehydration process for elephant foot yam using novel pulsed-microwave-vacuum combination followed by finish drying by microwave-vacuum. This research has been carried out to decrease industrial processing time, energy consumption and improving quality of the product. Industry will start adopting this new hybrid process of drying elephant foot yam on large scale.     

真空、脉冲真空、超声波对芒果渗透脱水的影响

为研究真空、脉冲真空和超声波对芒果渗透脱水动力学的影响,将大小为26mm×26mm×5mm的块状样品浸于65°Brix果葡糖浆溶液中,渗透脱水处理180min。结果表明,菲克扩散模型能很好地描述渗透脱水过程中芒果失水率和固增率的变化规律;真空、脉冲真空和超声波均促进了水分和固形物的扩散,其中超声波作用使水分扩散系数具有最大值,而真空处理导致了固形物扩散系数最高。