百合粉添加量对面团特性及面包品质的影响

为拓宽百合的应用渠道,提高面包的营养价值,研究了百合粉添加量(0%,5%,10%,15%,20%)对面团的微观结构、糊化特性、流变学特性以及面包品质的影响。结果表明:随着百合粉添加量增大,混合粉的持油性先降低后增加,持水性显著增加(P<0.05)。添加了百合粉后,面团的糊化温度升高,回生值和峰值黏度下降,面团的弹性模量和黏性模量均呈上升趋势。百合粉的添加,破坏了面筋蛋白原本均匀致密的微观结构;使面包的硬度显著增大(P<0.05),弹性、内聚性、胶黏性、咀嚼性、回复性、比容和感官评分显著降低(P<0.05);改变了小麦面团的特性和面包的品质,在小麦粉中添加5%~10%的百合粉,能保证面包较高的感官品质。     

热烫过程中百合粉的主要营养成分、微观结构及其功能特性

为明确不同热烫方式对百合粉理化特性的影响,以卷丹百合鳞茎为原料,分别采用沸水和蒸汽热烫处理不同时间(0,20,40,60,80 s),研究百合粉的主要营养成分、表观形态、粒径分布、功能特性及其热力学特性在不同热烫过程中的变化规律。结果表明:采用沸水热烫和蒸汽热烫处理不同时间,百合粉理化特性发生显著变化。随沸水热烫时间的延长,百合淀粉含量呈先上升后下降的趋势,沸水热烫60 s淀粉含量增至最高(76.80%),蒸汽热烫致百合淀粉含量从67.33%降至52.82%,呈下降趋势;经两种热烫方式处理的蛋白质含量均先降后升。未热烫的百合粉颗粒光滑圆润,以卵圆形淀粉小颗粒为主。经两种热烫处理的淀粉小颗粒逐渐减少,百合粉中的大颗粒先膨大变粗糙,而后破碎变小。热烫处理后百合粉粒径分布主峰向右偏移。未热烫的百合粉平均粒径为16.58μm,经热烫处理的百合粉粒径随热烫时间的延长均呈现先升高后降低的趋势,其中沸水热烫40 s和蒸汽热烫60 s处理的平均粒径最大,分别为78.97μm和66.53μm。百合粉透光率随贮藏时间的延长而呈下降趋势;未热烫和不同热烫方式处理的百合粉膨胀度和溶解度均随温度的升高呈增大趋势。沸水热烫使百合粉热力学特性消失,蒸汽热烫处理致百合粉的糊化温度升高,未热烫百合粉糊化焓为5.40 J/g,经蒸汽热烫40 s时降至最低1.26 J/g,蒸汽热烫60 s时热力学特性消失。     

利用蔗渣制备膳食纤维的研究

以我国南方资源丰富的蔗渣为原料，经适当工艺加工制得的食用蔗渣纤维粉含有26．5×10－2纤维素、43×10－2半纤维素和19．5×10－2木质素，膨胀力与持水力分别是4．5ml／g与500×10－2，是一种良好的天然食用纤维粉。     

百合多糖的纯化与化学结构鉴定研究

本研究从百合水提液中分离纯化得到两种多糖LP1、LP2,得率分别为鲜百合重0.55%、0.25%,经纸层析和凝胶柱层析鉴定均为单一组分,将这两种多糖进行气相色谱和凝胶柱层析分析,结果如下:LP1由葡萄糖、甘露糖组成,比例为1:2.46,分子量为7.94×104LP2由葡萄糖、半乳糖、甘露糖、阿拉伯糖、半乳糖醛酸组成,比例为1:0.73:2.6:1.8:0.84,分子量1.815×104     

基于相对湿度的小麦淀粉/谷朊粉混合粉失水速率的调控

为探究相对湿度对小麦淀粉/谷朊粉基制品失水速率的影响规律,为失水速率调控奠定理论基础,以小麦面条主要组分富淀粉组分(淀粉)和富蛋白质组分(谷朊粉)为模式试验材料,设计淀粉占比分别为100%,90%,50%,25%和0%的淀粉/谷朊粉混合粉。调节环境的相对湿度构建样品水分活度与环境相对湿度差值逐渐降低(22%~2%)、基本不变(22%~22%)和逐渐增加(22%~37%)3种物理模型。分析混合粉在3种模型下的失水速率。结果表明,在水分活度与相对湿度差值逐渐降低模型、基本不变模型、逐渐增加模型中,淀粉占比100%,90%,50%,25%和0%混合粉的平均失水速率分别为2.26×10-3~6.41×10-3,2.20×10-3~6.83×10-3,3.06×10-3~7.39×10-3,3.74×10-3~6.79×10-3[(mg/mg含水量)/min]和4.31×10-3~7.15×10-3[(mg/mg含水量)/min]。结论:小麦淀粉/谷朊粉混合粉的失水速率随样品水分活度与环境相对湿度差值的增加而增加;谷朊粉(0%淀粉含量)的平均失水速率高于淀粉(0%谷朊粉含量),随着淀粉占比的增加,混合粉的平均失水速率呈下降趋势。     

真空—蒸汽脉动烫漂预处理对百合

将真空—蒸汽脉动烫漂预处理技术应用于百合的烫漂预处理,研究蒸汽烫漂时间、烫漂循环次数和真空度对百合烫漂后干燥特性、水分有效扩散系数、色泽和复水比的影响。结果表明：蒸汽烫漂时间、烫漂循环次数和真空度均对烫漂后百合的干燥特性有显著性影响,当蒸汽烫漂时间30 s,烫漂循环3次,真空度90 kPa时,百合烫漂充分,提高了细胞间的通透性并抑制PPO、POD酶的活性,烫漂后在60 ℃热风下干燥,最短为11.7 h;干燥后的百合片色泽L^*值为83.65、ΔE值为5.18,接近于新鲜百合色泽;复水比最高为1.49 g/g,水分有效扩散系数最大为6.85×10^-10 m²/s;综合评分最高为0.98。     

微波烫漂预处理下百合热风干燥特性及动力学模拟

以兰州鲜百合为研究对象,将微波烫漂技术应用到百合热风干燥加工中。研究不同微波烫漂时间、微波功率和热风温度对百合干燥特性的影响,并利用Weibull分布函数对其干燥动力学曲线进行拟合、分析。结果表明:Weibull函数能够较好地拟合在不同试验条件下百合的干燥过程,百合干燥是典型的降速干燥;模型的尺度参数α与微波时间、微波功率及热风温度均相关,并且随着微波烫漂时间的增长、微波功率增大及热风温度的升高而减小;模型的形状参数β与微波时间和微波功率有关,但热风温度对β的影响较小。计算求出干燥过程中水分有效扩散系数D_eff值在3.374~5.563×10-9 m2·min-1之间,当微波烫漂时间越长、微波功率越大及热风温度越高时,其值越大。通过阿伦尼乌斯公式计算得到百合的干燥活化能E_a为23.68 kJ/（mol·K）。本研究可为百合微波烫漂-热风干燥加工提供参考。     

百合功能性因子的研究进展

介绍了百合中百合多糖、百合皂甙、仙水秋碱、酚酸甘油脂、磷脂、无机元素、百合膳食纤维等功能性因子的研究进展,尤其是在功能性因子的化学组成与结构、物化特性、生理与药理功能等方面的研究。进一步研究百合功能性因子具有重要的理论意义和实用价值。     

兰州百合粉的研制

以兰州百合为原料,通过兰州百合干法制粉、湿法制粉和喷雾干燥制粉工艺的对比研究,确定兰州百合适宜采用干法制粉工艺,干法制粉百合护色液最佳配方为异VC钠0.5%,柠檬酸0.10%,食盐2%;又对百合粉复配工艺进行研究,确定百合粉复配的较优条件为:百合粉45%、稳定剂1.0%、蔗糖18%,增香剂0.8%,食盐0.5%,麦芽糊精34.7%。本研究为兰州百合粉工业化生产提供了可靠工艺参数。     

热发光萤石的稀土元素分析

对中国发现的不同颜色、具热发光性与不具热发光性萤石的稀土元素特征进行了对比研究。结果表明,具热发光性绿色萤石的Y(33.7×10-6～57.5×10-6)、Ce(17.1×10-6～53.1×10-6)、La(11.30×10-6～9.46×10-6)、Nd(7.17×10-6～8.87×10-6)、Dy(4.34×10-6～7.00×10-6)、Gd(2.37×10-6～5.12×10-6)相对富集,具热发光性紫色萤石的这6种稀土元素相对亏损,这也许是其发光性相对较弱的原因,而不具热发光性萤石的这6种稀土元素的质量分数相当低。     

Lily Starch—An Underutilized and Non-Conventional Source: Properties and Applications

Lily belongs to the genus Lilium of the family Liliaceae. Starch is the main component of lily bulbs which accounts for 53–69% of their dry weight. Lily starch (LS) has B-type X-ray diffraction characterized by a peak at 5.6°, 17°, 22°, and 24°. The swelling and solubility of the LS are significantly higher than rice and corn starches. The gelatinization temperatures of the LS are much lower than maize but higher than wheat and potato starches. The pasting temperature, peak, breakdown, and setback viscosities of lily starches are falling within the range; 66.1–72.7 °C, 1409–3940 cP, 88–1206 cP, and 445–1952 cP, respectively. The range for initial temperature, gelatinization temperature range, and enthalpy for lily starches is also 56.5–64.0 °C, 3.8–10.3 °C, and 3.9–13.9 J g⁻¹, respectively. This review focuses on the recent advances in the understanding of the composition, structure, and properties of lily starches. Furthermore, the limited modification associated with lily starches is also discussed. There is a bold attempt to compare the properties of lily starch with that of the commercial starches of corn and potato.     

Pasting,thermal, gel texture,resistant starch and colour properties of unripe banana flour from 10 desert banana varieties cultivated in South Africa

Unripe banana flour is a potential commercial ingredient in various food products for increased resistant starch and reduced gluten contents. In the present study, the pasting (rapid visco-analysis), gel texture (penetration test), thermal (differential scanning calorimetry), colour (tri-stimulus colour indices) and the resistant starch properties of unripe banana flour produced from different dessert banana varieties (n?=?10) cultivated in South Africa, were analysed and juxtaposed to wheat and maize flour. The functional properties varied significantly (p?≤?0.05) between banana varieties, and from wheat and maize flours, to various extents. Selected functional property ranges of unripe banana, wheat and maize flours, respectively included; flour colour index (63.16–76.42, 77.34 and 80.96), paste viscosity (405.5–556.6, 124.7 and 115.6 RVU), gelatinization temperature (64.67–71.21, 71.11 and 69.95?°C), gel firmness (7.24–11.44?×?10^??2 N, 3.49?×?10^??2 N and 6.56?×?10^??2 N) and resistant starch content (19.9–47.4, 2.8 and 2.2% w/w). Multivariate analysis (principle component analysis) showed that the unripe banana flours from different varieties were distinguished from each other based on the pasting temperature. The unripe banana flours were distinguished from both wheat and maize flour based on breakdown and peak paste viscosities. The breakdown viscosity was the most positively related measure to the resistant starch content with a linear regression R-squared value of 0.898, indicating a significant role played by granule structure in resistance to enzymatic hydrolysis. The present research demonstrates that selection of appropriate dessert banana variety is important when replacing staple flours (wheat and maize) with unripe dessert banana flour as a functional ingredient.     

Selective extraction and quantitative analysis of non-starch and starch lipids from wheat flour.

Wheat flour non-starch lipids (lipids not bound to starch) were quantitatively extracted with water-saturated n-butanol (WSB), benzene-ethanol-water (10:10:1, by vol.) or ethanol-diethyl ether-water (2:2:1, by vol.) in 10min at 20 °C. Starch lipids (lipids bound to starch) were subsequently extracted with WSB at 90–100 °C. Carotenoid pigments were quantitatively extracted with the non-starch lipids. There was no significant hydrolysis of esterified fatty acids and no detectable autoxidation of unsaturated acids in the hot solvent extracts. Non-starch and starch lipids from a high grade spring wheat flour and three grades of winter wheat flour were separated by thin-layer chromatography and quantified as fatty acid methyl esters (FAME) by gas-liquid chromatography (g.l.c.) using heptadecanoic acid (or its methyl ester) as internal standard. Total flour and starch lipids after acid hydrolysis were also converted to FAME for quantitation by g.l.c. Non-starch lipids consisted of 59–63% non-polar (neutral) lipids, 22–27% polar glycolipids and 13–16% phospholipids. Steryl esters, triglycerides, and all the diacyl galactosylglycerides and phosphoglycerides were present only in non-starch lipids. Starch lipids consisted of 6–9% non-polar (neutral) lipids (mostly free fatty acids), 3–5 % polar glycolipids and 86–91 % phospholipids (mostly lysophosphatidyl choline). Starch lipids were almost exclusively monoacyl lipids. Factors are given for converting weight of FAME into weight of original lipid for all individual lipid classes in wheat which contain O-acyl groups. Factors for total lipids are: total starch lipids = FAME × 1.70, total non-starch lipids = FAME × 1.20, and total flour (non-starch + starch) lipids = FAME × 1.32. Similar factors could be used to convert weight of lipids obtained by conventional acid hydrolysis methods into weight of unhydrolysed lipids. Phospholipid contents are given by: total starch phospholipids = P × 16.51, total non-starch phospholipids = P × 23.90, total flour phospholipids = P × 17.91.     

Utilization of germinated ancient wheat (Emmer and Einkorn) flours to improve functional and nutritional properties of bread

Germinated and untreated ancient (Einkorn and Emmer) and modern (Esperia) wheat flours (0, 5, 10, 15 and 20%) were used in bread dough to improve functional and nutritional properties of bread according to (3 × 2 × 5) x 2 factorial design. Utilization of wheat varieties in the germinated form increased the ash, total dietary fiber (TDF), total yellow pigment (TYP), total phenolic content (TPC), antioxidant activities, Ca, Fe and Mg content of bread, and also the most increments in those values (except TYP) were observed in Emmer flour usage. Germinated wheat flour decreased the mean phytic acid contents of bread samples from 313.32 mg/100 g to 291.81 mg/100 g compared to untreated wheat flour. The use of ancient wheat flour (einkorn and emmer) gave lower bread volume compared to modern bread wheat flour. The use of germinated wheat flour decreased the crust and crumb L* values of the breads but increased the a* and b* values. As a result, increasing ratios of germinated ancient wheat flour increased the functional component and nutritional value of the bread, and at the same time, its usage at low ratio contributed positively to the technological quality of the bread.     

Some properties of polyphenol oxidase from lily

A study of crude polyphenol oxidase (PPO) from lily bulbs was carried out to provide information useful for guiding food processing operations. Optimum pH for the enzyme activity in the presence of catechol, were 4.0 and 7.0 at room temperature(approximately 20 °C) and the enzyme was stable in the pH range from 5.0 to 6.5 at 4 °C for 10 h. Its optimum temperature was 40 °C and the heat inactivation of the enzyme followed first‐order kinetics. Lily PPO possessed a diphenolase activity toward catechol, catechin and gallic acid; catechin was the best substrate for the enzyme considering the V_max/K_m ratio. The most effective enzyme inhibitor was sodium sulphite, although ascorbic acid, l ‐cysteine and thiourea were also effective inhibitors at high concentration. But NaCl and citric acid were poor inhibitors of the enzyme. Data generated by this study might help to better prevent lily bulbs browning.     

Physicochemical,functional and antioxidant properties of flour from pearl millet varieties grown in India

Indian pearl millet varieties were selected, milled to flour and studied for their proximate composition, hunter color, functional, and antioxidant properties. Proximate composition and hunter color values differed significantly (p < 0.05) among varieties. Hunter L* value was found the highest for HHB-223 flour whereas a*, b* and ΔE was the highest for W-445 flour. Flours also showed significant variations in their total phenolic content (TPC), total flavonoids content (TFC), antioxidant activity (DPPH) and metal chelating activity. Variety GHB-732 showed the highest values for TPC (3137 µg GAE/g) and DPPH (46.7 %) activity. TFC was, however, found the highest for HC-10 (2484 µg CE/g) variety. Several significant correlations were observed among different flour properties as revealed by both pearson correlations and principal component analysis. Formulation of chapatti resulted in decrease in TPC, TFC, DPPH values when compared to its flour. However, reverse was observed for metal chelating activity.     

Rice flour — A functional ingredient for premium crabstick

This study was performed to evaluate rice flour as a functional ingredient for premium crabstick and develop a commercially viable recipe. Physicochemical properties of crabstick pastes with 42% surimi, with various rice flour concentrations (0, 1, 3, and 5%), and other ingredients were evaluated. The physical properties were measured during refrigeration and frozen storage. Rice flour measured at various concentrations (5 to 40% in water) using a DSC demonstrated similar patterns with an endothermic peak at around 63.5°C. During refrigerated storage, the strength of gels increased gradually, while cohesiveness stayed mostly unchanged. During frozen storage, water retention ability (WRA) gradually decreased as freeze-thaw (F/T) cycles were extended, however the water reduction was minimized as rice flour concentration increased. The optimum level was 1% rice flour concentration for chilled and frozen crabstick. Two crabstick samples (control and 1% rice flour) demonstrated no difference in strength and cohesiveness.     

魔芋粉湿法微粉碎机械力化学效应研究

研究湿法微粉碎对魔芋粉产生的机械力化学效应。结果发现 ,经湿法微粉碎处理 ,魔芋粉的粒径由原精粉的 87 47%以上不能通过 12 0目筛变为 95 5 4%以上能通过 12 0目筛 ,魔芋粉颗粒形态由椭球形异细胞变成不规则的微小碎片 ,但颗粒总体粒度和形态较为均一 ;经湿法微粉碎处理后 ,魔芋粉葡甘聚糖重均分子质量由 1 5 6× 10 6u下降为 0 83× 10 6u ,魔芋粉色度得到一定改善 ,充分溶胀时间由 2 40min缩短为 60min ,溶胶粘度由 2 94Pa·s提高为 8 2 8Pa·s ;凝胶强度由 5 1 3 0Pa增强为 5 8 94Pa。     

Functional Properties of Raw and Heat Processed Cowpea (Vigna unguiculata, Walp) Flour

The functional properties, gelation, water and oil absorption, emulsification, foaming and protein solubility of raw and heat processed cowpea flour were determined. The effects of pH and NaCl concentration on some of these functional properties were also investigated. Protein solubility vs pH profile showed minimal solubility at pH 4. Water and oil absorption capacities of raw flour were 2.4 g/g and 2.9 g/g, respectively, while heat processed flour gave 3.6 g/g and 3.2 g/g, respectively. Addition of NaCl up to 0.4% improved the emulsification capacity of raw flour while a decrease was observed in the heat processed flour after 0.2%. Least gelation concentration of raw flour was found to be 16% and heat processed flour, 18%.