保护剂及冷休克处理对纳豆菌冻干后存活率的影响

对冷冻干燥法制备纳豆菌活菌制剂过程中保护剂及冷休克处理对纳豆菌存活率的影响进行了研究,通过单因素实验和正交实验筛选出了最佳保护剂组合:脱脂乳粉10%、麦芽糊精3%、蔗糖5%、抗坏血酸0.5%,并确定了最优冷休克处理条件:8℃处理5h.在以上两因素协同作用下,纳豆菌冻干后的存活率可达90.9%.     

纳豆菌微生态制剂加工中两种干燥方法的比较

本文比较了加工纳豆菌微生态制剂过程中真空冷冻干燥和喷雾干燥两种工艺对制剂活菌数、纳豆激酶活力及纳豆菌存活率的影响,结果表明:两种干燥方法下制剂最高活菌数分别可达1.21×109CFU/g和0.96×109CFU/g,最高存活率分别为84.71%和67.49%,最高酶活力分别为11516.58IU/g和7203.96IU/g。     

不同干燥方式对纳豆干粉品质影响

以纳豆活菌数为指标,比较真空冷冻干燥和热风干燥对纳豆中活菌数的影响,并对不同干燥方式制成的纳豆粉感官评定。试验结果表明,鲜纳豆经真空冷冻干燥12 h后,纳豆菌的存活率为35.04%,而鲜纳豆在(80~85)℃温度下烘烤6 h,纳豆菌的存活率则为100%,水分含量均保持在1.5%~3.0%。而且纳豆烘干粉比纳豆冻干粉具有更好的感官品质。因此,热风干燥的方法更适用于纳豆粉的工业化生产。     

高活性天然酵母发酵剂的优化

目的：研究标准化稳定天然酵母发酵剂的制备工艺,探究干燥工艺及保护剂对天然酵母活性的影响,并研究其贮藏活性。方法：选用多种水果制备天然酵母,研究其发酵过程并分离菌株通过ITs和16s基因测序在数据库中比对鉴定优势菌株。以干燥工艺处理后的存活率和贮藏活性为指标,通过选择干燥工艺、样品状态和保护剂配方来获得最佳方案。结果：葡萄天然酵母制备的面包具有最好的比容、孔隙度和硬度。在此基础上,以干燥存活率和贮藏活性为指标得到两种保护效果较好的配方：① 冷冻干燥优势菌种菌液,脱脂乳粉35%、麦芽糊精7.5%和海藻糖25%,干燥存活率约为93%;② 天然酵母整体喷雾干燥,脱脂乳粉35%、麦芽糊精10%和海藻糖15%,干燥存活率约为90%。结论：喷雾干燥的发酵剂贮藏活性下降较快,而冷冻干燥的发酵剂贮藏活性较强。     

肉类发酵菌种真空冷冻干燥保护剂研究进展

直投式肉用发酵剂因其具有使用方便、发酵性能优良等优势而倍受关注,但是菌粉冻干存活率低的问题一度成为阻碍肉类发酵行业发展的壁垒。真空冷冻干燥过程中加入冻干保护剂能有效避免冷冻干燥对菌种的损伤,提高存活率。从肉类发酵剂、直投式肉用发酵剂、真空冷冻干燥技术对细胞损伤机理、冷冻干燥保护剂4个方面综述了冻干保护剂在提高肉类发酵菌种冻干存活率方面的应用,以期为后续冻干保护剂的筛选提供参考。     

两种干燥方式对酸奶干制品中乳酸菌活性的影响分析

采用离心喷雾干燥和冷冻干燥两种方式干燥酸奶混料,其中乳酸菌经过微胶囊化。用稀释平板的方法检测原混料以及两种干燥产品复水后乳酸菌总数,计算复水产品中乳酸菌的存活率。比较得出两种干燥方式对原混料乳酸菌活性都有影响,存活率分别为17.1%和53.5%,冷冻干燥方式对乳酸菌的活性影响比较小。     

静电喷雾干燥微囊化乳双歧杆菌BL03

静电喷雾干燥是新型微囊化益生菌的方法。该文研究了静电喷雾干燥乳双歧杆菌BL03保护剂和微囊化工艺,通过单因素和正交试验,优化得到保护剂组成为海藻糖14%,亚麻酸10%,CaHPO 46%,β-环糊精11%(均为质量分数),最佳静电喷雾微囊化工艺进风温度80℃,物料泵流量30 r/min,静电压25 kV,存活率高达89.26%。乳双歧杆菌BL03菌粉扫描电镜图片显示,静电喷雾干燥微囊化包埋效果最好,包埋率高达93.3%。比较静电喷雾干燥、常规干燥和乳化冷冻干燥3种微囊化方法,静电喷雾干燥模拟胃液作用2 h,存活率超过80%;模拟肠液作用4 h,存活率达到75%;25℃下储存12个月,活菌数存活率超过70%,均明显优于常规干燥和乳化冷冻干燥,说明静电喷雾干燥微囊化方法适合包埋乳双歧杆菌。     

干燥方式对紫薯全粉水合特性及抗氧化能力的影响

以紫薯"万紫56"为原料,研究了热风干燥、冷冻干燥、微波干燥和喷雾干燥对其全粉的水合特性及抗氧化能力的影响。结果表明,冷冻干燥制备紫薯全粉的持水性和复水性均高于热风干燥、微波干燥和喷雾干燥,但溶水力最差。干燥使紫薯全粉中花色苷损失了27.64%~52.66%,冷冻干燥和喷雾干燥紫薯粉中花色苷的保留量最大,并显著(p0.05)高于其他两种干燥方式;喷雾干燥制备紫薯粉的DPPH自由基清除力及还原力最强,而冷冻干燥紫薯粉的脂质过氧化抑制力最强。     

真空冷冻干燥与喷雾干燥长双歧杆菌的工艺比较研究

为有效延长双歧杆菌的保存期和耐受性,利用真空冷冻干燥及喷雾干燥法制备活性菌粉。研究两种干燥方法的工艺参数,并对干燥得到的活性菌粉性能进行比较。真空冷冻干燥法制备的长双歧杆菌活性菌粉的活菌数为7.98×109CFU/g、存活率90.9%、含水量3.8%,4℃保藏90d后活菌数为2.5×108CFU/g,菌粉的水溶性好;喷雾干燥法制备的活性菌粉的活菌数为4.4×109CFU/g、存活率82.2%、包埋率71.9%、含水量5.6%,4℃保藏90d后活菌数为4×108CFU/g,菌粉在水中的溶解时间较长。真空冷冻干燥成本较高、操作时间长、菌粉的保藏期较短;而喷雾干燥工艺简单、生产成本低、工作效率高,包埋的菌粉保藏期较长。     

不同干燥方式对酸菜粉品质及抗氧化性能的影响

实验考察了在冷冻干燥、喷雾干燥、真空干燥、微波真空干燥、热风干燥及挤压膨化等干燥方式下酸菜粉的物理特性、营养特性及抗氧化特性的变化。结果表明:冷冻干燥酸菜粉中乳酸含量、游离氨基酸含量最高,比热风干燥高48.39%,45.45%;挤压膨化处理后酸菜粉可溶性膳食纤维含量最高,比热风干燥高64.21%;喷雾干燥制作的酸菜粉冲调性最好,比热风干燥高32.39%;喷雾干燥和真空冷冻干燥制得的酸菜粉流动性较好,休止角分别比热风干燥小25.51%,23.14%;真空冷冻干燥的容重最小,比热风干燥低31.17%;冷冻干燥处理粉的堆积密度最小,比热风干燥低42.31%;冷冻干燥水合能力最高,挤压膨化处理的酸菜粉吸油能力最高,分别比热风干燥高61.61%,77.14%;冷冻干燥无论对羟基自由基清除率还是脂质过氧化物抑制率的影响均最小。     

复凝聚法鼠李糖乳杆菌微胶囊工艺优化及储藏稳定性

为提高鼠李糖乳杆菌在贮藏过程中的稳定性,以明胶、阿拉伯胶为壁材,采用复凝聚法制备鼠李糖乳杆菌微胶囊。研究以湿态微胶囊的包埋率为指标,考察pH、壁材浓度、转速和菌添加量对复凝聚法微胶囊制备的影响,在单因素试验的基础上进行正交试验,优化最佳工艺。将最优条件下的湿微胶囊进行喷雾干燥和真空冷冻干燥,并在不同水分活度和不同温度条件下研究了喷雾干燥和真空冷冻干燥鼠李糖乳杆菌微胶囊的储藏稳定性。结果表明,pH 3.75、壁材浓度1.5%、转速200 r/min、菌添加量109 CFU,此条件下制备的鼠李糖乳杆菌微胶囊包埋率最高,为93.21%;复凝聚法制备的鼠李糖乳杆菌湿微胶囊干燥后,每克真空冷冻干燥微胶囊的活菌数比喷雾干燥微胶囊高1.9个对数值;储藏时水分活度越低,温度越低,鼠李糖乳杆菌微胶囊的储藏性越好;与喷雾干燥微胶囊相比,储藏时真空冷冻干燥微胶囊在高水分活度下较稳定,且在不同水分活度、不同温度条件下的活性均高于喷雾干燥微胶囊。因此复凝聚法制备的鼠李糖乳杆菌微胶囊真空冷冻干燥后能更好的保护鼠李糖乳杆菌,延长其储藏期。     

喷雾干燥虾夷扇贝粉中3 种添加剂用量的预测模型

为防止虾夷扇贝粉喷雾干燥过程引起氨基酸等热敏性成分的损害,本实验采用3 种食品添加剂对氨基酸进行包埋。以虾夷扇贝匀浆后加入中性蛋白酶和木瓜蛋白酶水解,在水解液中加入不同配比的β- 环糊精、变性淀粉和CMC,研究添加剂配比对虾夷扇贝粉氨基酸保留率的影响。结果表明：当在虾夷扇贝水解液中加入25.61%β- 环糊精、25.52% 变性淀粉和2.96%CMC 时,控制喷雾干燥机进口温度125℃、出口温度80℃、进风量0.9m3/min 喷雾干燥得到的虾夷扇贝粉氨基酸保留率为56.43%,比对照氨基酸保留率提高了18.81%。通过Box-Benhnken 中心组合试验设计和响应面分析,得到氨基酸保留率Y 对β- 环糊精(X1)、变性淀粉(X2)、CMC(X3)的回归模型,该模型能预测氨基酸保留率,为虾夷扇贝粉的工业化生产提供参考。     

Chemical and microbial evaluation of Egyptian dried egg white prepared by different techniques

Egg white was dehydrated (pan drying, spray drying) without and with glucose removal (using bacteria, yeast and enzyme). Although, moisture, protein and ether extract percentage in spray dried samples were, in general, in the same range as the imported Swiss made spray dried sample (as standard), yet the least moisture percentage was found in samples in which sugar was removed by yeast. The standard sample had the best solubility (99.79%). followed by the spray dried sample desugarized by yeast (99.67%). Samples in which Streptococcus lactis was used gave the highest percentage of insoluble matter (4.24%). Pan dried and spray dried samples were similar in solubility. The total microbial counts were found to decrease in egg white after drying (max. 4.9 × 10 org. in prepared samples, zero in the standard). Salmonella was absent in all dried samples. There are variations in the type of protein fractions of liquid egg white when the enzyme treatment or controlled bacterial fermentation were used. When yeast fermentation was used a decrease in some protein fractions was noticed in comparison with the nondesugarized sample. The dehydrated egg white proteins indicate that there was no difference between the different techniques applied for glucose removal, between drying methods and between prepared samples and imported one; 5 fractions were obtained in each sample.     

干燥方式对不同接枝度的大豆分离蛋白-麦芽糊精聚合物性质影响

以大豆分离蛋白(SPI)和麦芽糊精(MD)为原料制备不同接枝度的SPI-MD聚合物,研究比较喷雾干燥和冷冻干燥两种处理方式对不同接枝度下的SPI-MD聚合物性质的影响,如溶解度、疏水性、持水性、乳化性、乳化稳定性及起泡性、泡沫稳定性等的影响。实验表明,喷雾干燥样品的溶解性,表面疏水性和乳化性高于冷冻干燥样品;冷冻干燥样品则具有较好的持水性。另外,两种干燥样品的乳化稳定性非常接近。不同接枝度的两种干燥样品起泡性差异较大,且泡沫稳定性都相对较差。     

Manufacture of jameed using a spray drying process: a preliminary study

Jameed powder was manufactured using a controlled fermentation with a yogurt starter followed by spray drying. The composition and physical properties of the spray dried jameed were analysed and compared with local sun dried jameed. It was found that the moisture content of the spray dried jameed was lower than that of the sun dried product. In addition, the dispersibility of the spray dried jameed was higher and the average particle size was smaller; wettability, bulk density and colour were comparable between the two products.     

干燥方式对蛋清蛋白理化性质和功能特性的影响

为探究干燥方式对蛋清蛋白（egg white protein,EWP）功能特性的影响及其内在机理,分别通过喷雾干燥与真空冷冻干燥制备蛋清蛋白粉,并对其蛋白结构、理化性质与功能特性进行研究。结果表明,与蛋清液（EWP-C）相比,喷雾干燥使蛋清蛋白（EWP-P）的内源性荧光强度降低,表面疏水性和表面游离巯基含量增大。傅里叶变换红外光谱分析显示,EWP-P的α-螺旋、β-折叠和β-转角分别为16.30%、25.72%和40.23%,冷冻干燥蛋清蛋白（EWP-D）分别为20.43%、24.32%和35.69%。不同pH下,EWP-D的溶解度均高于EWP-P,表面张力小于EWP-P。此外,EWP-P的接触角为99.62°,高于EWP-D（接触角为65.97°）,表明喷雾干燥能显著提高蛋白的疏水性（P<0.05）。EWP-D在不同pH下的乳化性、乳化稳定性以及起泡性均大于EWP-P,但起泡稳定性更小,这与EWP-D较高的溶解性与较低的表明疏水性有关。荧光倒置显微镜及激光共聚焦扫描显微镜分析表明EWP-D乳液的微粒更小,分布更均匀,其稳定性高于EWP-P。综上,喷雾干燥蛋清蛋白的β-折叠结构较多,表面游离巯基含量和表面疏水性较高,具有较好的凝胶性;冷冻干燥蛋清蛋白的表面疏水性较小,且表面张力小、溶解度大,具有更好的乳化能力与起泡性。     

The influence of additives and drying methods on quality attributes of fish protein powder made from saithe (Pollachius virens)

BACKGROUND: Fish protein powder (FPP) is used in the food industry for developing formulated food products. This study investigates the feasibility of increasing the value of saithe (Pollachius virens) by producing a functional FPP. Quality attributes of spray and freeze‐dried saithe surimi containing lyoprotectants were studied. A freeze‐dried saithe surimi without lyoprotectants was also prepared as a control sample. RESULTS: The amount of protein, moisture, fat and carbohydrate in the FPPs were 745–928, 39–58, 21–32 and 10–151 g kg^?1. Quality attributes of FPPs were influenced by the two drying methods and lyoprotectants. The highest level of lipid oxidation was found in the control and the second highest in the spray‐dried FPP. The spray‐dried fish protein had the lowest viscosity among all FPPs. Gel‐forming ability of samples with lyoprotectants was higher than that of the control. Water‐binding capacity, emulsion properties and solubility of the freeze‐dried fish protein containing lyoprotectants were significantly higher than spray‐dried and control samples. However, functional properties of spray‐dried FPP were higher than the control sample. CONCLUSION: It is feasible to develop value‐added FPP from saithe surimi using spray‐ and freeze‐drying processes, but freeze‐dried FPP containing lyoprotectant had superior functional properties and stability compared with spray‐dried sample. Both products might be used as functional protein ingredients in various food systems. Copyright © 2010 Society of Chemical Industry     

Comparative survival and evaluation of functional probiotic properties of spray-dried lactic acid bacteria

The effect of spray drying on the viability and retention of key probiotic properties like acid and bile tolerance and cholesterol assimilation of three probiotic lactic acid bacteria (LAB) ( Lactobacillus plantarum CFR 2191, Lactobacillus salivarius CFR 2158 and Pediococcus acidilactici CFR 2193) has been studied. More than 97% survival was exhibited by the three LAB (1% cell suspension) spray dried with maltodextrin and nonfat skimmed (NFSM) as carriers. LAB cultures spray dried with maltodextrin showed significantly greater ( P ≤  0.05) retention of functional properties than those with NFSM. The results highlight a cost-effective way of producing large quantities of selected probiotic cultures with functional properties for neutraceutical application.     

Foam-mat drying technology: A review

This article reviews various aspects of foam-mat drying such as foam-mat drying processing technique, main additives used for foam-mat drying, foam-mat drying of liquid and solid foods, quality characteristics of foam-mat dried foods, and economic and technical benefits for employing foam-mat drying. Foam-mat drying process is an alternative method that allows the removal of water from liquid materials and pureed materials. In this drying process, a liquid material is converted into foam that is stable by being whipped after adding an edible foaming agent. The stable foam is then spread out in sheet or mat and dried by using hot air (40–90°C) at atmospheric pressure. Methyl cellulose (0.25–2%), egg white (3–20%), maltodextrin (0.5–05%), and gum Arabic (2–9%) are the commonly utilized additives for the foam-mat drying process at the given range, either combined together for their effectiveness or individual effect. The foam-mat drying process is suitable for heat sensitive, viscous, and sticky products that cannot be dried using other forms of drying methods such as spray drying because of the state of product. More interest has developed for foam-mat drying because of the simplicity, cost effectiveness, high speed drying, and improved product quality it provides.     

Effects of spray drying on antioxidant capacity and anthocyanidin content of blueberry by-products

The effect of spray drying on degradation of nutraceutical components in cull blueberry extract was investigated. Samples collected before and after spray drying were tested for antioxidant capacity using oxygen radical absorbance capacity (ORAC(FL) ) and total phenolics; and for individual anthocyanidins. In Study 1, four different levels of maltodextrin (blueberry solids to maltodextrin ratios of 5: 95, 10: 90, 30: 70, and 50: 50) were spray dried a pilot-scale spray dryer. There was significantly higher retention of nutraceutical components with increased levels of maltodextrin indicating a protective effect of maltodextrin on the nutraceutical components during spray drying. In Study 2, the air inlet temperature of the spray dryer was kept constant for all runs at 150 °C, with 2 different outlet temperatures of 80 and 90 °C. The degradation of nutraceutical components was not significantly different at the 2 selected outlet temperatures. ORAC(FL) reduction for blueberry samples after spray drying was 66.3% to 69.6%. After spray drying, total phenolics reduction for blueberry was 8.2% to 17.5%. Individual anthocyanidin reduction for blueberry was 50% to 70%. The experimental spray dried powders compared favorably to commercial blueberry powders. Results of the study show that use of blueberry by-products is feasible to make a value-added powder. PRACTICAL APPLICATION: Results can be used by producers to estimate final nutraceutical content of spray-dried blueberry by-products.