A novel enzyme cross-linked gelation method for preparing food globular protein-based transparent hydrogel

In this work, a novel two-step method for preparing food globular protein-based hydrogel with transparent appearance and stable network was described. First, soy glycinin dispersion (6% w/v) was heated at 95 °C for 30 min in order to obtain partial unfolding conformation and expose more residues for the following enzymatic cross-linking. An anionic polysaccharide, dextran sulfate (DS), was added before glycinin was heated, forming highly charged complexes with glycinin and maintaining the transparency of the dispersion. Microbial transglutaminase (MTGase) was introduced for gelation, creating a covalent network. Transparent cold-set hydrogels could be obtained when the weight ratio of DS to glycinin was over 1/200. It was found that larger amounts of DS and lower ionic strength were favorable for increasing the transparency of the gels. At pH 7.0, effects of DS amounts and ionic strength on the rheological and mechanical properties of the hydrogels were investigated. Hydrogels with distinctive textural properties could be obtained by different combinations of DS amount and ionic strength. Scanning electron microscopy observation indicated that the addition of DS could promote the formation of regular and stable gel network.     

锐孔-凝固浴法制备大蒜油微胶囊的工艺

文章主要研究了锐孔-凝固浴法制备大蒜油微胶囊的工艺过程和方法。试验以大蒜油为芯材,以海藻酸钠为壁材,氯化钙为固化液,探讨了海藻酸钠浓度、芯材与壁材比例、乳化剂浓度、氯化钙浓度及乳化温度等影响成型的主要因素。通过三元二次回归正交实验确定了制备大蒜油微胶囊的最佳工艺条件,并对最佳工艺条件下制备的微胶囊进行包埋率的测定。结果表明:锐孔法制作大蒜油微胶囊的最佳工艺条件为壁材海藻酸钠的浓度为1.4%,芯材大蒜油与壁材的配比为3.8:1,乳化剂的浓度为0.3%,乳化温度为65℃,凝固浴氯化钙的浓度为2%;包埋率可以达到77.21%。     

自组装多肽水凝胶包埋大蒜精油的控释研究

研究Fmoc–F自组装多肽水凝胶对大蒜精油的包埋作用、控释特性和稳定作用。结果表明:该水凝胶对大蒜精油的包埋率可达到97.07%;当p H≥6.5时,包埋大蒜精油后的水凝胶结构分解率不高于12.17%,可提高大蒜精油的稳定性;当5p H6.5时,凝胶结构部分分解;当p H≤5.0时,凝胶结构迅速分解,快速释放大蒜精油抑制大肠杆菌的生长;感官评价表明Fmoc–F水凝胶可显著掩盖大蒜精油的不良气味。     

Microencapsulation of flaxseed oil in flaxseed protein and flaxseed gum complex coacervates

Flaxseed oil, a rich source of omega-3 fatty acids, was microencapsulated in a novel matrix formed by complex coacervation between flaxseed protein isolate (FPI) and flaxseed gum (FG). This matrix was crosslinking with glutaraldehyde. Liquid microcapsules with three core (oil)-to-wall ratios (1:2, 1:3 and 1:4) were prepared and spray-dried or freeze-dried to produce powders. The microencapsulation efficiency, surface oil, morphology and oxidative stability of these microcapsules were determined. The spray-dried solid microcapsules had higher oil microencapsulation efficiency, lower surface oil content, smoother surface morphology and higher oxidation stability than the freeze-dried microcapsules. The highest microencapsulation efficiency obtained in spray-dried microcapsules was 87% with a surface oil of 2.78% at core-to-wall ratio 1:4 and oil load 20%. The oxidation stability obtained from spray-dried microcapsules at core-to-wall ratio of 1:4 was nearly double that of the unencapsulated flaxseed oil.     

酶法脱除亚麻籽胶的工艺研究

采用酶法脱除亚麻籽胶,并考察了酶的种类、酶解温度、酶解时间、pH值、酶加入量、总料液比对亚麻籽胶脱除效果的影响。通过单因素和正交试验确定了酶解脱除亚麻籽胶的最佳工艺条件:酶制剂为果胶酶、温度55℃、时间4h、pH值为3.5、酶加入量为100u/g、总料液比为1:6,该条件下亚麻籽的脱胶量可以达到9.53g。     

Optimization and release characteristics of catechin-loaded calcium pectinate beads by internal gelation

Food Science and Biotechnology - The aim of this study was to optimize the composition of catechin-loaded calcium pectinate gel (CPG) beads formed using internal gelation and to evaluate the...     

HPLC外标法测定亚麻籽油中4种环肽含量的研究

以环肽标准样品定性,采用外标法定量,建立了HPLC测定亚麻籽油中环肽A、环肽C、环肽D和环肽E的方法。采用固相萃取法提取亚麻籽油中的环肽,用Diamonsil C18色谱柱,以乙腈和水为流动相梯度洗脱,柱温35℃,二极管阵列检测器在波长214 nm处进行检测,30 min内完成对4种环肽的分离检测。结果表明:该方法的线性范围为10~160μg/m L,相关系数大于等于0.999 5;环肽A、环肽C、环肽D、环肽E的平均加标回收率分别为94.62%、92.25%、84.07%和100.14%。用该方法测定不同工艺制取的亚麻籽油中环肽的含量,发现未经过精炼的亚麻籽油中环肽含量高于市售亚麻籽油的,其中,冷榨工艺比热榨工艺更能保留亚麻籽油中的环肽。     

亚麻籽油的热稳定性研究

通过加热试验,研究了亚麻籽油的热稳定性。结果表明:在高温加热条件下,亚麻籽油中α-亚麻酸含量有所降低,总反式脂肪酸的含量提高;在200℃和250℃条件下保持120 min后,亚麻籽油中α-亚麻酸的含量分别下降了6.1%和57.7%,总反式酸的含量分别为4.47%和20.89%。说明亚麻籽油作为烹调用油,烹调温度在200℃以下比较合适,加热时间不宜过长。     

Characteristics of flaxseed hull oil

Oils from two commercial flaxseed hulls extracted by six procedures were evaluated for physicochemical characteristics. Oil yield ranged from 9% to 28% depending on solvent and extraction. Lipid fractionation of crude flaxseed hull oil yielded 92.5% neutral lipids, 3.1% phospholipids, 2.4% acidic lipids and 2.1% free fatty acids. Flaxseed hull oil exhibited three thermal transitions between −35 and −13 °C with solvent dependent polymorphism. Thermal oxidation by differential scanning calorimetry (DSC) revealed three step oxidation of flaxseed hull oil with mean onset and oxidation temperatures at 121 and 150–253 °C, respectively depending on the extraction procedure. Flaxseed hull oil exhibited two-fold difference (0.6–1.2 μm Trolox equivalent/g) in antioxidant activity measured by a photochemiluminescence (PCL) assay. Supercritical CO₂ extracted the most oil with the highest antioxidant capacity of all evaluated procedures resulting in a defatted flaxseed hull containing the highest (53 mg/g) secoisolariciresinol diglucoside (SDG) level.     

Antioxidant activity of flaxseed oil

Effective concentration of antioxidants and its reactivity toward peroxil radicals (constant k7) have been measured by the chemiluminescence technique for flaxseed oil. Effective concentration of antioxidants is shown to depend on the technology of producing flaxseed oil; period of seed storage before use; and storing duration of flaxseed oil also. Minor component content of flaxseed oil, which may be the members of antioxidant pool, has been quantitatively estimated.     

提高大蒜精油提取得率的酶调控技术

报道了通过调控蒜氨酸酶活性提高大蒜精油提取得率的方法,并初步确定了提取大蒜精油的最适工艺条件。实验结果表明其提取得率较常规方法提高2倍。     

高效液相色谱法测定蒜油中大蒜素的含量

建立高效液相色谱法测定蒜油中大蒜素含量的方法。采用HPLC法ZORBAX Eclipse XDB-C18柱(4.6mm×150mm,5μm);流动相:甲醇-水-甲酸(75∶25∶0.1);流速1mL/min;检测波长225.8nm。大蒜素浓度在45.12～225.6mg/L范围内呈良好线性关系(r=0.9998),平均回收率为99.72%,RSD为0.27%(n=5)。高效液相色谱法测定蒜油中大蒜素的含量,测定方法操作简单、结果准确、重复性好。     

制取高不饱和度亚麻籽油的方法研究

以亚麻籽油为原料,采用干法分提对其进行了分离改性,进一步分离出富含高不饱和脂肪酸的亚麻籽油。研究了搅拌速率、冷却速率、养晶时间、结晶温度对亚麻籽油液态油得率、碘值的影响。得到最佳的工艺条件为:搅拌速率15 r/min,冷却速率4℃/h,养晶时间12 h,结晶温度-8℃。在最佳工艺条件下所得液态油碘值(I)为198 g/100 g,液态油得率为89.2%。通过分析样品油与成品油的脂肪酸组成、含量和0℃固体脂肪含量发现,成品油的饱和脂肪酸和固体脂肪含量较样品油明显降低。     

热重法对亚麻籽油的氧化动力学研究

本文以亚麻籽油为研究对象,研究了不同升温速率对亚麻籽油DSC曲线和TG曲线的影响,并分别根据DSC曲线和TG曲线对亚麻籽油的氧化进行了动力学求解。研究结果表明,升温速率对亚麻籽油DSC曲线和TG曲线的形状和氧化起始温度均有显著影响,利用TGA技术和DSC技术求解出的亚麻籽油氧化活化能基本一致。      

炒籽温度对压榨亚麻籽油品质的影响

采用不同温度对亚麻籽进行炒籽并压榨制油,对压榨亚麻籽油的感官品质、理化指标及营养成分进行分析,研究炒籽温度对压榨亚麻籽油品质的影响。结果表明:随着炒籽温度的升高,压榨亚麻籽油的气味从坚果芳香过渡到严重焦糊味,色泽加深,在195℃炒籽45 min时形成热榨亚麻籽油特有的浓香型风味;营养成分如VE、总酚以及甾醇含量随炒籽温度升高而逐渐减少,在255℃炒籽45 min时,3种营养成分的损失率分别为75. 7%、76. 5%和88. 9%;酸价、过氧化值、茴香胺值、K232值、K270值随炒籽温度升高而增加,且炒籽温度对压榨亚麻籽油中主要脂肪酸含量有显著影响;适当炒籽对压榨亚麻籽油的氧化稳定性是有利的;高温炒籽压榨亚麻籽油中的营养成分含量与其理化指标密切相关,进而共同影响压榨亚麻籽油的品质。     

Development of carboxymethyl chitosan hydrogel beads in alcohol-aqueous binary solvent for nutrient delivery applications

Carboxymethyl chitosan (CMCS) hydrogel beads were normally prepared from a composite formulation with other polymers, such as alginate. In present study, a novel method was developed to prepare CMCS hydrogel beads in alcohol-aqueous binary solvents. The morphology and shape of the beads were highly dependent on alcohol concentration. The most spherical hydrogel beads were obtained with 3% calcium and 30% alcohol concentration. The chemical crosslinking agent, glutaraldehyde, was needed to maintain the hydrogel integrity and morphology upon drying. Vitamin D3, a model nutrient, was encapsulated into the beads and 96.9% encapsulation efficiency was obtained. The effects of freeze-drying and room temperature drying were studied on the swelling behaviors and release properties in simulated gastrointestinal conditions. Possible mechanisms for CMCS hydrogel beads formation in binary solvents were discussed. The CMCS hydrogel beads prepared in 30% alcohol-aqueous binary solvent may be a promising delivery system for hydrophobic nutrients or drugs.     

亚麻籽油微胶囊的制备及理化性质研究

为减缓亚麻籽油中不饱和脂肪酸的氧化,该实验利用喷雾干燥技术,用大豆蛋白、麦芽糊精作为壁材,亚麻籽胶充当乳化剂,对亚麻籽油进行包裹,制备微胶囊,并对微胶囊产品进行理化指标的测定。结果表明:微胶囊产品含油率为38.03%,表面油含量为4.76%,包埋率达到87.50%,水分含量为1.30%,产品干燥,流动性好;颗粒分布均匀,基本呈球体;常温下溶解度良好;吸水性实验表明,产品易吸水,影响产品品质。     

亚麻籽油抗动脉粥样硬化作用的研究进展

研究表明ω-3脂肪酸能够降低心血管疾病的发生危险,其生物学和分子效应能够调节动脉粥样硬化的形成和发展,包括对炎症反应、血小板功能、血压、甘油三酯水平及动脉粥样斑块稳定性的调节作用。ω-3脂肪酸包括α-亚麻酸、二十碳五烯酸和二十二碳六烯酸。亚麻籽油含有丰富的多不饱和脂肪酸,是α-亚麻酸最丰富的来源之一。此外,有研究表明亚麻籽油可有效减缓动脉粥样硬化的发展。主要对亚麻籽油抗动脉粥样硬化作用的研究现状进行综述,以期为研究亚麻籽油对动脉粥样硬化的改善作用提供理论参考。     

亚麻籽低温冷榨制油工艺研究

介绍了亚麻籽及亚麻籽油的主要成分及营养功能,阐述了亚麻籽低温冷榨制油的工艺过程,并对各关键工序进行了详细说明。