Viability of Bifidobacteria Strains in Yogurt with Added Oat Beta-Glucan and Corn Starch during Cold Storage

Abstract: Probiotics must be consumed at a level of 10⁷ CFU/mL for successful colonization of the gut. In yogurts containing beneficial cultures, the survival of probiotic strains can quickly decline below this critical concentration during cold storage. We hypothesized that beta-glucan would increase the viability of bifidobacteria strains in yogurt during cold storage. Yogurts were produced containing 0.44% beta-glucan (concentrated or freeze-dried) extracted from whole oat flour and/or 1.33% modified corn starch, and bifidobacteria (B. breve or B. longum) at a concentration of at least 10⁹ CFU/mL. All yogurts were stored at 4 °C. Bifidobacteria and yogurt cultures, Streptococcus thermophilus and Lactobacillus delbureckii subsp. bulgaricus, were enumerated from undisturbed aliquots before fermentation, after fermentation, and once a week for 5 wk. S. thermophilus and L. bulgaricus maintained a concentration of at least 10⁸ CFU/mL in yogurts containing concentrated or freeze-dried beta-glucan regardless of starch addition, and in the control with no added beta-glucan or starch. Similarly, the probiotic, Bifidobacterium breve, survived above a therapeutic level in all treatments. The addition of beta-glucan prolonged the survival of Bifidobacterium longum at a concentration of at least 10⁷ CFU/mL by up to 2 wk on average beyond the control. Further, the inclusion of concentrated beta-glucan in yogurt improved survival of B. longum above 10⁷ CFU/mL by 1 wk longer than did freeze-dried beta-glucan. Study results suggest that beta-glucan has a protective effect on bifidobacteria in yogurt when stressed by low-temperature storage. Practical Application: This study suggests that beta-glucan (oat fiber) may improve bifidobacteria survival in yogurt during refrigerated storage.     

Changes in Starch and Protein on Extrusion of Corn Starch and Sunflower Protein Blends

We investigated the use of electron spin resonance spectroscopy (ESR) and the spin labelled fatty acid, 16 doxylstearic acid (16-DSA) in the study of starch and protein modification during extrusion processing of corn starch (CS), corn meal (CM), and their blends with sunflower protein isolate (SPI). Spectra due to binding of the spin probe to starch and protein were identified. Changes in spectra after extrusion of all materials indicated that: (1) ~90% of the starch was modified (gelatinized); (2) The globular protein structure was disrupted. These changes demonstrate that spin probes and ESR spectroscopy may be used to study starch and protein modification during extrusion and other food processes.     

利用蛋白质"指纹"技术鉴定加拿大啤酒大麦的品种和纯度

开发了操作简便、电泳图谱清晰、分辨率高的啤酒大麦种子醇溶蛋白SDS—PAGE电泳方法，利用Gel—Pro软件对电泳图谱进行条带分析和比较，建立了每个品种的蛋白质“指纹”，组成加拿大啤酒大麦品种标准图谱库。利用Cross Checker2．8和MEGA3软件对供试啤麦品种进行遗传聚类分析，结果与传统分类相近。进行了人工混种试验，并成功将该技术应用于公司2004年进口加拿大啤麦的品种和纯度鉴定。     

利用蛋白质“指纹”技术鉴定加拿大啤酒大麦的品种和纯度

开发了操作简便、电泳图谱清晰、分辨率高的啤酒大麦种子醇溶蛋白SDS-PAGE电泳方法,利用Gel-Pro软件对电泳图谱进行条带分析和比较,建立了每个品种的蛋白质“指纹”,组成加拿大啤酒大麦品种标准图谱库。利用CrossChecker2.8和MEGA3软件对供试啤麦品种进行遗传聚类分析,结果与传统分类相近。进行了人工混种试验,并成功将该技术应用于青岛啤酒股份有限公司2004年进口加拿大啤麦的品种和纯度鉴定。     

利用酶制剂降解烤烟烟叶中淀粉和蛋白质的研究

为探索外加酶制剂施于调制后原烟发酵过程的效果,设计了不同加酶量、作用时间、相对湿度和温度处理的方法来降解烤烟烟叶中的淀粉和蛋白质的试验。结果表明,单一施用中性蛋白酶对烤烟蛋白质的降解率不理想,综合使用α-淀粉酶、葡萄糖淀粉酶针对不同的部位均有不同的相对最佳处理组合。在各等级相对最佳条件下施加α-淀粉酶、葡萄糖淀粉酶后再喷施中性蛋白酶发酵烟叶后针对3个等级烟叶的淀粉和蛋白质有所降解,氨基酸含量均有显著提高,但还原糖含量、总氮和烟碱含量变化不明显。     

利用蛋白质"指纹"技术鉴定啤酒大麦的品种和纯度

采用操作简便、分辨率高的种子醇溶蛋白SDS-PAGE电泳技术对常用澳大利亚和法国啤酒大麦进行鉴定，利用Gel-Pro软件对电泳图谱进行条带分析和比较，建立了澳大利亚和法国啤酒大麦品种的生化标准“指纹”图谱库。并对供试的啤麦品种进行遗传聚类分析，结果与传统分类相近。     

Development of a Single Kernel NIR Barley Protein Calibration and Assessment of Variation in Protein on Grain Quality

In this paper, we describe results from a preliminary experiment on the development of a near infrared reflectance (NIR) calibration for single kernel (SK) % protein content in barley. The SKNIR calibration was developed using kernels from breeding lines and commercial barley varieties with a range in protein content of 7.3% to 16.6% “as is”. The calibration model produced an R² = 0.903, while the validation set had a R² = 0.837 with a standard error of cross validation and a standard error of prediction of 0.8% for both the calibration and validation sets respectively. The calibration was then used to estimate the variation in % protein of 4,000 single kernels from a commercial variety (Gairdner at 9.3% protein) by segregating kernels into six sub‐groups (<7.8%, 7.9–8.3%, 8.4–9.0%, 9.1–9.7%, 9.8–10.4%, >10.5% “as is”). These sub‐groups then had additional grain quality tests carried out including grain size, thousand kernel weight and NIR estimates of % protein, starch, hardness and barley hot water extract (HWE). The results showed an increase in grain size, and a decrease in HWE from the low to high % protein sub‐groups. While only a single variety was used in the SKNIR protein segregation study, the results suggested SKNIR could be used to screen for the variation in grain quality traits based on variation in protein content.     

Gelation Properties and Morphology of Heat-induced Starch/Salt-soluble Protein Composites

ABSTRACT: The formation of starch (potato, corn, and rice) and ham salt-soluble protein (SSP) composite during heating was studied using thermal and rheological analysis. Measurements from differential scanning calorimetry showed that the peak temperature of starch/SSP composite was slightly lower than that of the corresponding starch. SSP exhibited an initial G' higher than zero and became a rigid structure as indicated by the decrease in tan δ after heating. The data of tan 8 δ illustrated that starch and protein transition proceeded independently. Scanning electron microscopy and light microscopy with the aid of histologic technique revealed the network and distribution of starch and protein in starch/SSP composite.     

种植密度和播期对周麦18碳氮转运、籽粒淀粉及蛋白质含量的影响

在大田条件下,研究了不同种植密度和播期对冬小麦品种周麦18干物质和氮素积累转运及其籽粒产量和品质的影响.结果表明,不同播期各密度处理开花期和成熟期单茎干物质和氮素积累量均随播种密度降低而增加(150×104株/hm2>225×104株/hm2>300×104株/hm2),晚播相应降低了单茎干物质和氮素积累量及穗部积累量.正常播期低密度(150×104株/hm2)和晚播中等密度(225×104株/hm2)提高了成熟期营养器官总的干物质和氮素积累量,增加了营养器官花前贮藏干物质总转运量及其对籽粒重的贡献率.正常播期中低密度(150×104株/hm2和225×104株/hm2)和晚播中高密度(225×104株/hm2和300×104株/hm2)处理相应提高了籽粒淀粉、蛋白质含量与产量及籽粒产量,保证了小麦籽粒产量和品质同步提高.因此,晚播小麦通过适当增加播种密度,可以改善植株的碳氮代谢状况,提高籽粒产量.本试验条件下,偏多穗型晚播小麦兼顾高产和优质的正常播期和晚播小麦适宜播种密度分别为:150～225×104株/hm2、225～300×104株/hm2.     

四种大麦间泡沫蛋白质含量差异的比较

本实验建立了从麦芽中提取泡沫蛋白的便捷方法,并利用考马斯亮蓝法(Bradford 法)和SDS-PAGE 电泳技术进行定量分析,直观地检测和比较了四种大麦和麦芽中泡沫蛋白质的含量、组分和各组分的相对含量及其变化情况,可为评估大麦和麦芽质量以及预测啤酒泡沫的品质提供借鉴。     

小麦籽粒淀粉品质与蛋白质品质关系的初步研究

通过测定32个小麦品种籽粒的11个淀粉品质性状及10个蛋白质品质性状，分析了各性状之间的简单相关关系。结果表明：直链淀粉含量与清蛋白含量显著正相关，与支链淀粉含量、膨胀势、高峰粘度、衰减值、粗蛋白含量、醇溶蛋白含量、谷蛋白大聚合体含量、沉降值显著负相关；支链淀粉含量与糊化温度显著负相关，与沉降值、面筋指数显著正相关；膨胀势、高峰粘度、低谷粘度、最后粘度两两间极显著正相关；衰减值与醇溶蛋白含量、谷蛋白大聚合体含量、沉降值，糊化温度与球蛋白含量呈显著正相关；回生值与面筋含量，峰值时间与沉降值显著负相关。文章还分析了淀粉品质和蛋白质品质与蒸煮类食品品质的关系。     

大麦发芽过程中内源激素对大麦蛋白组分及蛋白酶活力影响

选用进口大麦Gairdner和国产大麦甘啤二号,分析比较了两种大麦发芽过程中赤霉素、生长素和脱落酸等内源激素含量的变化。结果表明,3种激素在两种大麦发芽过程中均呈现出随发芽时间上下波动的趋势,且两种大麦在发芽过程中各激素含量的变化规律基本一致,同时探讨促进生长激素和抑制生长激素的比例对大麦发芽过程中蛋白酶活力的影响。实验结果表明,随着促进生长激素和抑制生长激素比例的升高,两种大麦发芽时蛋白酶活力均有较大幅度的增长,加速了大麦发芽过程中醇溶蛋白含量的降低及热稳定蛋白的释放。     

四倍体大麦嫩叶中SOD CAT和可溶性蛋白质含量分析

比较研究了3个四倍体大麦品种和1个二倍体大麦品种的不同叶龄嫩叶中的出汁率、超氧化物歧化酶（SOD）、过氧化氢酶（CAT）两种自由基清除酶活性和可溶性蛋白质含量,结果表明,四倍体大麦嫩叶与二倍体大麦出汁率相当,但含有比二倍体大麦更丰富的SOD、CAT及可溶性蛋白质,可作为制备大麦嫩叶汁粉的优质原料。     

板栗冷藏和沙藏处理中蛋白质、水分、糖和淀粉含量的变化

测定冷藏和沙藏两种贮藏方式不同贮藏期板栗的蛋白质、还原糖、淀粉和水分的含量,结果表明：两种贮藏方式对板栗的蛋白质含量的变化有显著性影响,对还原糖、淀粉和水分的变化影响不显著;各个贮藏期中蛋白质和水分的变化不显著,淀粉和还原糖的变化显著.     

添加淀粉和蛋白质对挂面力学特性的影响

通过向小麦粉中分别添加玉米淀粉、红薯淀粉、马铃薯淀粉以及大豆分离蛋白,制作挂面并对挂面的弹性模量、抗弯能力进行分析.结果表明:无论添加何种淀粉,挂面的弹性模量都会随添加量的增大而减小;添加大豆分离蛋白能使挂面弹性模量明显上升,若添加量超过0.6％弹性模量会有所回落但仍明显高于对照组.添加3种淀粉和大豆分离蛋白都会使挂面的抗弯能力下降.用断裂应力评价挂面抗弯能力比使用端部轴向位移量可靠度更高.综合考虑挂面的弹性模量及抗弯能力,挂面中玉米淀粉、马铃薯淀粉、红薯淀粉以及大豆分离蛋白的添加量分别不宜超过10％、5％、5％和0.8％.     

磨粉方式对苦荞粉粉质特性及体外消化特性的影响

选用超微、石磨、钢磨、湿磨4种磨粉方式对苦荞籽粒进行磨粉,分析比较苦荞粉破损淀粉含量、粒径分布、微观结构、水合特性、冻融稳定性、黏度特性等粉质特性并采用酶解法模拟体外淀粉消化测定不同时间点的总淀粉水解率。研究结果显示:磨粉方式对苦荞粉粉质特性及体外消化特性影响差异显著,其中超微粉碎能显著减小苦荞粉粒径大小(D[4,3]=32.09μm),提高其亮度值(L=88.92)以及淀粉对酶的敏感度;湿磨粉淀粉颗粒形态完整,破损淀粉质量分数最低,为4.25%,冻融稳定性好,回生值低(3 732 cP),不易老化;石磨粉粉糊衰减值低,粉糊热稳定性好,淀粉水解缓慢;刚磨粉对各项指标的影响均不突出。不同磨粉方式对苦荞粉的影响不一,超微粉是一种理想的苦荞深加工食品原料,湿磨粉则适合冷冻食品加工,石磨粉更适合慢消化食品加工,而刚磨粉适合与普通食品用粉。     

大豆分离蛋白、淀粉、卡拉胶对鸡肉肠硬度的影响

研究大豆分离蛋白、淀粉、卡拉胶对鸡肉肠硬度的影响。采用中心组合设计的方法,建立二次多项式回归方程的预测模型。结果显示:大豆分离蛋白能极显著提高鸡肉肠的硬度(p<0.01),淀粉、卡拉胶则影响不显著(p>0.05)。得出硬度预测方程,并优化得到最佳组合:大豆分离蛋白7.28%、淀粉10.11%、卡拉胶0.44%条件下鸡肉肠有最大硬度737.232 g。     

核磁共振波谱法分析淀粉中含有的蛋白质和脂肪

淀粉、蛋白质和脂肪由于结构复杂使解析其结构非常繁琐和困难,致使对各种淀粉中含有的蛋白质、脂肪的深入研究受限。随着高分辨核磁共振波谱(NMR)技术飞速发展,它在淀粉的结构研究中发挥了日益重要的作用。综述了淀粉、蛋白质和脂肪一维核磁共振(1HNMR,13CNMR)的特征和应用核磁共振波谱法分析淀粉中含有的蛋白质、脂肪。     

豆类种子中的内肽酶在植物蛋白与淀粉生产中的应用研究

因可供食品用的蛋白酶制剂种类少、价格高,限制了酶法加工技术发展。植物生理学证明:种子中存在着种类繁多的酶,应该研究其工业利用的可能性。我们确定豆类、油料种子中内肽酶工业利用为研究方向,已发现许多有价值的现象并开发了几项新工艺、新技术。主要有:(1)发现几种快速激活种子内肽酶的方法,证明种子内肽酶的直接工业利用是可实现的。并发现内肽酶活化过程与动物消化蛋白酶活化过程是相似的。(2)发现热灭活的种籽内肽酶可再次活化,为利用高温豆粕及植物蛋白改性提供了理论基础。这一性质具有理论研究和广泛的工业利用价值。(3)豆奶生产:现行方法原理是灭活脂肪氧化酶,需要快速烘干、破碎、风选脱皮、热碱水灭酶、真空脱味等工艺过程脱除豆味、添加油脂并均质乳化(提高smooth感,去除chalkiness)工艺过程和设备复杂,利用大豆肽酶可以同时完成以上工艺过程,设备只比豆浆生产线多一台酶反应器。(4)利用大豆内肽酶法可以改变大豆蛋白的功能,如豆奶粉、大豆分离蛋白等产品的溶解性,并可以使大豆蛋白改为亲油型或乳化型。(5)微生物发酵法生产豆类淀粉在我国有1400年历史,只有这种淀粉可生产粉丝,多年来研究者都在研究微生物的作用。我们发明利用豆类内肽酶生产淀粉的新工艺方法,淀粉特性同于微生物法,而且可回收豆类分离蛋白。(6)大豆分离蛋白的工业生产是使用碱提酸沉的化学方法,利用豆类内肽酶可以直接生产豆类分离蛋白,內肽酶被活化后可以完成植物蛋白的溶解和沉淀过程,,并且可以实现连续反应,提高了生产效率并简化了设备。种子内肽酶这一新的研究方向可产生更多理论研究课题和开发更多新技术,新产品。前景是广阔的。     

Comparison of the GFFF and LALLS Methods for the Measurement of Starch Granule Size Distribution in Spring Barley Caryopses

A newly developed method GFFF (Gravitational Field‐Flow Fractionation) and the well known method LALLS (Low Angle Laser Light Scattering) were used to assess starch granule size distribution of ten varieties of spring barley. As a distribution criterion, the ratio of starch granule content larger than 8 μm (type A) and smaller than 8 μm (type B) was chosen. Both methods divided the observed set in a similar way. Varieties Akcent, Forum and Atribut formed a variety set with the highest ratio of large and small starch granules. Varieties Scarlet and Kompakt had intermediate ratios. The remaining five varieties Amulet, Novum, Olbram, Tolar and Krona had the lowest ratios of large and small starch granules. Statistical analysis showed that there was a highly significant correlation between the GFFF and LALLS methods.