硒元素对黑木耳深层发酵的影响

为了获得富硒黑木耳菌丝,提高黑木耳菌丝的产量,改善黑木耳菌丝的品质,以亚硒酸钠作为硒源,用不同碳源有机物和氮源有机物进行黑木耳的深层发酵,研究pH值和温度对黑木耳深层发酵的影响。实验结果表明,黑木耳菌丝生长的最佳条件为：葡萄糖作碳源,豆饼粉作氮源,pH5.3,温度28℃。在此最佳条件下加入不同浓度的亚硒酸钠溶液进行培养,通过测定黑木耳菌丝的生物量,粗多糖含量和硒吸收率,表明亚硒酸钠浓度在60mg/kg以下时可提高黑木耳菌丝产量;在60～100mg/kg之间时会降低黑木耳菌丝产量;而在60mg/kg时,硒的吸收率达到最高。     

超声波协同果胶酶提取黑木耳粗多糖

采用超声波协同果胶酶提取黑木耳粗多糖,先加入底物质量分数1%的果胶酶,在pH=5.0,50℃酶解2 h,对黑木耳进行预处理。再通过正交试验,得到超声波辅助提取黑木耳粗多糖的最佳工艺条件为:超声波功率400 W,超声波时间7 min,料液比1∶80(g/mL),浸提温度90℃,浸提时间2 h,在此条件下得到黑木耳粗多糖提取率为19.84%。在相同条件下,该提取率高于热水直接浸提法和超声波辅助热水提取法得到黑木耳粗多糖的提取率。实验表明,采用超声波协同果胶酶提取黑木耳粗多糖是可行的。     

黑木耳多糖提取工艺条件的研究

黑木耳多糖是黑木耳子实体中的重要活性物质,除具有一般的生化性质外,还具有调节免疫功能、抗血栓、抑菌、降血糖、抗溃疡、抗肝炎和抗突变、降血脂和促进血清蛋白生物合成等多种功效。为优化黑木耳多糖的提取工艺,本文在单因素试验结果的基础上,选择料液比、提取温度、提取时间为自变量,黑木耳多糖的得率为响应值,研究各自变量交互作用及其对黑木耳多糖得率的影响,确定了黑木耳多糖提取的最佳条件为:提取温度60℃、料液比为1∶40、提取时间为2.5h,在此最佳提取条件下,黑木耳多糖的得率达到5.12%。对提取的黑木耳多糖的营养成分进行了分析,所制备的多糖以大分子多糖为主,还含有一定量的蛋白质、水分、还原糖及灰分,为一种粗多糖。     

黑木耳胶质对豌豆淀粉黏度和质构性质的影响

以黑木耳为原料,采用RVA和质构仪分别测定了黑木耳全粉、黑木耳多糖及黑木耳胶质对豌豆淀粉糊化黏度和质构的影响,发现黑木耳胶质对豌豆淀粉的影响效果明显好于黑木耳全粉和黑木耳多糖;然后与卡拉胶和明胶进行了比较并测定了溶解度和溶胀度.研究结果表明:添加8％黑木耳胶质的淀粉糊峰值黏度、谷值黏度、末值黏度和衰减值均显著提高,分别达到819、568、861、250 RVU,约是原淀粉的3倍;与添加卡拉胶和明胶相比,添加黑木耳胶质对提高豌豆淀粉糊黏度效果更明显,且添加黑木耳胶质的豌豆淀粉凝胶硬度、回复力和内聚力均较高;黑木耳胶质的添加使得豌豆淀粉的溶解度降低,并显著提高了豌豆淀粉的溶胀度.     

超声波提取黑木耳多糖及其体外抗凝血活性

通过单因素,正交试验对黑木耳超声波提取优化,经过离子交换层析柱纯化,对多糖组分抗凝血活性的初步研究。粗多糖提取最佳工艺条件为,超声频率为70 k Hz、料液比为1∶30(g∶m L)、超声时间为15 min、超声温度为70℃,黑木耳粗多糖得率为6.15%。粗多糖经阴离子交换柱DEAE Sepharose CL-6B分级纯化得4个组分AAP-1、AAP-2、AAP-3、AAP-4。活化部分凝血活酶时间(APTT)初步表明,黑木耳多糖组分AAP-2、AAP-3具有抗凝血活性。     

青椒香辣酱护绿护脆工艺的研究

实验对青椒香辣酱护绿护脆工艺进行研究,通过正交试验确定最佳工艺条件:护脆处理:0.35%CaCl2和0.5%海藻酸钠中浸泡青椒10 min;护绿处理:0.3%柠檬酸和0.5%异Vc钠溶液,65℃水浴25 min;炒制条件:100℃,5 min;杀菌条件:90℃杀菌10 min.     

黑木耳多糖的提取工艺

研究黑木耳多糖的提取工艺,以多糖得率为考察指标,在单因素试验结果的基础上,进行正交试验设计,考察液料比、时间、温度对多糖得率的影响.结果表明,温度是影响粗多糖得率的重要因素,水提法的最佳工艺为:液料比70(mL:g),提取时间4h,温度100 ℃,提取2次,pH为7.0.此条件下黑木耳多糖得率为32.24%,多糖含量为64.23%.     

响应面法优化黑木耳多糖酸奶工艺

目的 优化黑木耳多糖酸奶的生产工艺。方法 采用超声波辅助酶法提取黑木耳多糖,以黑木耳多糖和生牛乳为原料,保加利亚乳杆菌、嗜热链球菌为发酵剂,进行黑木耳多糖酸奶最佳工艺的研究,以感官评价为指标,采用单因素实验探究黑木耳多糖添加量、接种量及发酵时间对黑木耳多糖酸奶的影响,进一步通过响应面实验对黑木耳多糖酸奶工艺进行优化,并对酸奶品质进行评价。结果 确定了黑木耳多糖酸奶的最佳工艺条件:黑木耳多糖添加量0.15%,接种量3%,发酵时间4 h。在最优工艺条件下生产出的黑木耳多糖酸奶的感官评分达(91.26±0.05)分,与预测值接近,最终产品感官指标、理化指标及微生物指标均符合国家标准要求。结论 本研究开发出了一种比普通酸奶具有更高营养价值和保健功效的新型酸奶产品。     

黑木耳多糖的酶法提取、纯化及性质研究

本文以双酶法提取黑木耳粗多糖,利用DEAE-Cellulose 52和Sepharose CL-4B柱层析对其进行纯化,以Sephadex G-100凝胶柱层析测定了多糖的分子量。结果表明黑木耳多糖含有两个主要组分APE Ⅰ和APE Ⅱ,分子量分别为31.7×104和18.3×104,均为非淀粉类多糖,不含单糖、蛋白质、核酸及多酚类物质。     

黑木耳超微粉多糖相对分子质量分布及降血脂功能研究

采用酸法对黑木耳粗粉和超微粉多糖进行分离提取。研究了超微粉粗多糖DEAE-Cellul ose52离子交换层析的分离纯化工艺。样品分出两个峰,将超微粉与两个组分收集后浓缩,采用HPLC法分析多糖组成及相对分子质量分布,并做黑木耳超微粉多糖与粗粉多糖的降血脂功能动物试验。结果表明,最佳分离条件为:洗脱液浓度0.25mol/L,流速200s/mL,上样质量浓度3.5mg/mL。黑木耳经超微粉碎后多糖相对分子质量降低明显;相对于未经超微粉碎获得的粗多糖,超微粉碎后得到的多糖具有更明显的降血脂作用。     

两种海藻酸钠基凝胶的溶胀和质构性能

壳聚糖、果胶和海藻酸钠是天然多糖,具有良好的生物相容性和生物可降解性等优点。以CaCl_2为交联剂制备壳聚糖-海藻酸钠水凝胶和果胶-海藻酸钠水凝胶,研究Ca Cl2浓度、多糖质量比(壳聚糖与海藻酸钠、果胶与海藻酸钠)和交联温度对水凝胶在模拟人体胃肠道环境(pH 1.2胃、pH 6.8小肠、pH 7.4结肠缓冲溶液)中溶胀性能的影响。当壳聚糖或果胶和海藻酸钠质量比为1.25∶1、CaCl_2浓度为0.09 mol/L、温度为60℃时,制备的水凝胶在pH 1.2溶液中溶胀率最小,在pH 6.8和pH 7.4溶液中溶胀率较大;结果表明所制备水凝胶具有pH值敏感性。此外,在优化条件下水凝胶具有较好的质构性能。     

Quality of french fried potatoes as influenced by coating with hydrocolloids

Potato french fries were coated with a combination of calcium chloride and either pectin or sodium alginate at different levels. The best treatment was selected for the second coating with different hydrocolloids. Qualities of single- and double-coated french fries were evaluated. Potato french fries coated with sodium alginate as a first coating had less oil reduction and less quality than those coated with pectin. Single-coated french fries with a combination of 0.5% calcium chloride and 5% pectin had the highest reduction of oil content as well as the highest moisture content. Also, coated french fries at these levels exhibited higher red and yellow colours and were firmer than the control. Coated french fries with 0.5% calcium chloride and 5% pectin had higher sensory scores for all attributes compared to the control. French fries coated with carboxy methyl cellulose (CMC) as a second layer were more effective than those coated with pectin or sodium alginate in reducing the oil content. The incorporation of CMC at 1.5% level as a second layer reduced the oil content by 54%; however, the single coating with 0.5% calcium chloride and 5% pectin reduced the oil content by 40%. Double-coated french fries had higher moisture contents and firmer structures than the single coated french fries. Increasing the level of the hydrocolloid forming the second coating up to 1.5% resulted in non-significant differences in the sensory scores for all attributes. Scanning electron microscope photographs indicated that the single- or double-coating process was effective in protecting the cellular structure of potato tissues from the damage produced during deep-fat frying. ©     

海藻酸钠/纳米TiO2复合涂膜对采后番木瓜果实软化及细胞壁降解影响

为探究海藻酸钠/纳米TiO2(sodium alginate/nano-TiO2,SA/TiO2)复合涂膜处理抑制采后番木瓜果实软化的作用机理,以"日升10号"番木瓜为试材,采用SA/TiO2复合涂膜处理,研究采后番木瓜果实硬度、细胞壁组分含量和细胞壁水解酶活性的变化规律.结果表明,SA/TiO2复合涂膜处理能有效地抑...     

海藻酸钠包埋法固定硝基还原假单胞菌的研究

目的优化海藻酸钠和CaCl_2对硝基还原假单胞菌SP.001细胞的固定化条件。方法以海藻酸钠为载体,通过包埋法固定化谷氨酰胺酶,通过单因素实验和正交实验对固定化细胞制备条件进行优化。结果单因素实验中,当海藻酸钠和CaCl_2的浓度分别为4%和3%、酶液量与海藻酸钠的体积比为1:2、固定化时间为3 h时,包埋效果最好,测得固定化细胞回收率较高,可达80.5%。通过正交实验得出最佳组合为:酶液量与海藻酸钠体积比1:3,固定化时间3 h,海藻酸钠浓度4%,CaCl_2浓度3%,固定化细胞回收率达到85.78%。结论本研究优化了海藻酸钠包埋法固定硝基还原假单胞菌的条件,并对固定化细胞的性质进行探讨,为硝基还原假单胞菌所产的谷氨酰胺酶的固定化和应用提供参考。     

低温红肠在天然可食性膜包装条件下的货架寿命研究

以壳聚糖、海藻酸钠、大豆分离蛋白为原料制备天然可食性膜,通过测定可食性膜的水溶性、透明度、膜的厚度筛选出贮藏低温肉制品最优的可食性膜,并通过测定不同贮藏期低温红肠的感官评价、细菌总数、脂肪氧化值(TBARS)、H2S等指标研究可食性对低温肉制品货架期的影响,结果表明:低温红肠制品用1组(2%壳聚糖+1%冰乙酸)、2组(...     

Interactions in Protein/Polysaccharide/Calcium Gels

Protein-polysaccharide-calcium gels were prepared using combinations of crude myofibrillar protein, whey protein concentrate, sodium alginate, methylcellulose, low methoxyl pectin, carrageenan and CaCl. The nature of the interactions taking place in the gels and the effect of freezing or heating on viscosities and water losses were investigated. In most cases the stability of the gels was increased by freezing and lowered by heating. Myofibrillar protein with added whey protein concentrate formed stronger gels with the polysaccharide gums than did the myofibrillar protein extract alone. With the exception of methylcellulose gels, electrostatic interactions seemed to be the main forces involved in the formation and stability of the gels.     

Effect of microencapsulation on survival of Lactobacillus plantarum in simulated gastrointestinal conditions, refrigeration, and yogurt

In the present research the survival of free and microencapsulated cells of a new strain of Lactobacillus plantarum BL011 under stress conditions was tested in sodium alginate or pectin, coated with sodium alginate or chitosan. Results for the simulated gastrointestinal medium (SGT) showed no change in viability of cells in relation to the control. However, the simulated gastric medium (GM) drastically reduced the viability under the tested conditions, with no significant differences between free and immobilized cells. Under refrigerated storage viability of immobilized cells were greatly enhanced compared to the free microorganisms, and the treatments showing the lowest loss of viability were those of 4% (w/v) pectin, 3% (w/v) sodium alginate coated with chitosan and a mixture of 2% (w/v) sodium alginate and 2% (w/v) pectin, respectively. Loss of viability of immobilized L. plantarum in 3% alginate coated with chitosan in yogurt was of 0.55 log cycles during 38 days of storage. The results of this study suggest the efficiency of immobilization techniques to increase the survival of lactobacilli in yogurt under refrigerated storage.     

海藻酸-聚乙烯醇二元膜的结构表征与性能研究

由海藻酸钠和聚乙烯醇的水溶液共混,在3%的CaCl2水溶液中凝固,然后用1%的HCl水溶液处理,成功制得海藻酸/聚乙烯醇共混膜.采用红外光谱、X-射线衍射、原子吸收光谱和扣描电镜对共混膜进行了结构表征,并对共混膜的透光率、吸水率、保水率、力学性能、水蒸气透过率等方面进行了测试.结果表明,共混膜中海藻酸与聚乙烯醇分子间存在着强的相互作用及良好的相容性,其中Ca2+交联作用和海藻酸与聚乙烯醇分子间作用力、氢键等强的相互作用使共混膜理化性能得到了显著改善.     

复配胶体对长保质期面包用耐烘焙果味酱品质的影响

研究了可用于长保质期面包夹心耐烘焙果味酱的胶体,通过正交试验探讨了复配胶体对耐烘焙果味酱感官、质构、保水性及含耐烘焙果味酱面包品质的影响。结果表明,以低甲氧基果胶0.5%、褐藻酸钠0.3%、羧甲基纤维素钠0.3%或褐藻酸钠0.3%、羧甲基纤维素钠0.3%,可生产出酱体均匀细腻、流散性适宜、耐烘烤,与长保质期面包配合可保存3个月的耐烘焙果味酱。