Whole wheat bread: Effect of bran fractions on dough and end-product quality

Consumption of whole-wheat based products is encouraged due to their important nutritional elements that benefit human health. However, the use of whole-wheat flour is limited because of the poor processing and end-product quality. Bran was postulated as the major problem in whole wheat breadmaking. In this study, four major bran components including lipids, extractable phenolics (EP), hydrolysable phenolics (HP), and fiber were evaluated for their specific functionality in flour, dough and bread baking. The experiment was done by reconstitution approach using the 2⁴ factorial experimental layout. Fiber was identified as a main component to have highly significant (P < 0.05) and negative influence on most breadmaking characteristics. Although HP had positive effect on farinograph stability, it was identified as another main factor that negatively impacted the oven spring and bread loaf volume. Bran oil and EP seemed to be detrimental to most breadmaking characteristics. Overall, statistical analysis indicates that influence of the four bran components are highly complex. The bran components demonstrate multi-way interactions in regards to their influence on dough and bread-making characteristics. Particularly, Fiber appeared to have a high degree of interaction with other bran components and notably influenced the functionality of those components in whole wheat bread-making.     

淀粉酶提取小米米糠蛋白的工艺研究

[目的]探究小米米糠蛋白的提取工艺.[方法]以小米米糠为原料,先测定其营养成分,然后制备脱脂米糠,利用淀粉酶对小米米糠酶解处理进行米糠蛋白的提取,通过单因素试验对提取条件进行筛选.[结果]试验得到小米米糠蛋白的最佳提取工艺条件为:最佳料液比1∶10 g/ml,淀粉酶用量20 U/g,最佳反应时间2h,最佳反应温度60℃.[结论]研究可为小米米糠蛋白的提取提供理论依据.     

水稻种子中脂解酶活性的初步研究

 以粳稻H129为材料，对稻米的脂解酶进行了研究。水稻脂解酶主要位于胚芽及盾片部分，它含有数种性质不同的同功酶；灭菌与不灭菌水稻脂解酶活性的变化曲线不一致；与前人的研究结论相反，未萌发或休眠的米糖部分未检测出脂解酶活性。     

Effect of the addition of bran fractions on bread properties

High fibre breads were produced adding durum wheat bran fractions of different composition and particle size. Fresh products were characterized for texture, crumb grain, volume, colour, water status (water activity, moisture content, frozen water content, ¹H molecular mobility).     

适用于西瓜砧木育苗的菌糠基质筛选

以4 种菌糠为复合育苗基质对西瓜砧木进行育苗试验,考察各菌糠品种应用于西瓜砧木育苗的适用性,筛选出适用西瓜砧木育苗的菌糠品种。试验选取海鲜菇、杏鲍菇、金针菇以及茶树菇菌糠分别与蛭石混合配制成复合育苗基质,测定各基质的理化性状并进行西瓜砧木育苗试验。结果表明：杏鲍菇和金针菇菌糠容重相对较小,总孔隙度相对较少;海鲜菇、茶树菇菌糠育苗效果优于杏鲍菇和金针菇处理;海鲜菇菌糠:蛭石=4:1、茶树菇菌糠:蛭石=1:1 基质处理西瓜砧木壮苗指数达0.36、0.37,显著高于对照的草炭:蛭石=2:1处理。建议选择海鲜菇、茶树菇菌糠进行西瓜砧木育苗复合基质的进一步研发。     

Distribution and composition of phytosterols and steryl ferulates in wheat grain and bran fractions

Phytosterols and steryl ferulates are bioactive compounds accumulating in the bran and germ of wheat. However, little is known regarding their localisation and composition in the bran layers of the kernel. The aim of this study was to determine the distribution of phytosterols and steryl ferulates in the wheat grain and in the different layers of bran. The wheat fractions, produced by conventional debranning, aleurone separation and a novel electrostatic process, were analysed for phytosterol contents using GC–FID and for steryl ferulate contents using HPLC–UV. The compounds were identified by GC– and LC–MS. Phytosterols and steryl ferulates were concentrated in the bran layers. The steryl ferulates were accumulated in the intermediate layers, whereas the phytosterols were more evenly distributed in the intermediate layers and aleurone cell contents. The phytosterol composition varied within the wheat kernel, while the steryl ferulate composition was similar in different fractions. Sitosterol and campestanyl ferulate were the main compounds. The highest levels of phytosterols (up to 2117 μg/g) and steryl ferulates (up to 703 μg/g) were found in the pearling, aleurone and certain bran fractions. The phytosterol-rich fractions could be utilised in cereal foods to enhance the intake of health-promoting compounds from natural sources.     

Adherence within biological multilayered systems: Development and application of a peel test on wheat grain peripheral tissues

The wheat grain is surrounded by a multilayered system composed of different tissues differing in their composition and mechanical properties. Up to now, these properties have been determined using classical tensile tests. However no methodology exists to evaluate the inter-tissular adherence. With this purpose, a micromechanical device adapted to wheat tissue (5 tissues with thickness varying from 2 to 55 μm) was built in order to investigate an interface of industrial interest for wheat processing (between the aleurone layer and the nucellar epidermis). Taking into account the complexity of the peel force measured, the stored elastic energy on the peel arms was estimated using tensile tests of peel arms and was found to approximate 0.15% of the total peel force at low peel rates. The energy dissipated was investigated as a function of peel test parameters (angle, curvature radius and rate), and seems to have a minimal influence when low peel rates were applied (20 μm s⁻¹). The peel test was finally used to investigate the adherence distribution around the wheat grain using samples dissected in different directions. The bottom of the grain was the least adherent region, whereas the top of the grain towards the brush was the most adherent region. Even though the interpretation of the peel force was complex, this technique could be appropriate to evaluate the adherence within natural biological tissues.     

微波辅助提取蓝、紫粒小麦麸皮中色素的研究

为了探讨微波辅助提取蓝、紫粒小麦麸皮中色素的方法,以两个蓝粒小麦品种和两个紫粒小麦品种的麸皮为原料,以酸性乙醇为浸提剂,利用格兰仕WD900I型家用微波炉,研究了微波功率、提取时间、料液比（原料与提取剂的比例）和提取剂浓度等单因素对提取率的影响,并根据单因素试验结果,设计了四因素三水平正交试验。结果表明,4个因素对酸性乙醇微波辅助提取蓝、紫粒小麦色素的影响的大小顺序均为微波功率〉提取时间〉料液比〉提取剂浓度;每次加热3瓶（每瓶20或24mL）的最佳提取条件,微波功率均为450W,加热时间均为90s（间断加热,将最高加热温度控制在≤75℃）,溶剂均为70％乙醇溶液,料液比,蓝粒为1g：10mL,紫粒为1g：12mL。     

Pulsed laser ablation: A new approach to reveal wheat outer layer properties

A new methodology based on pulsed lasers has been developed in order to estimate wheat outer layer mechanical properties without sample preparation. Laser experiments were carried out with an Argon Fluoride (λ = 193 nm) excimer laser source delivering pulses of 15 ns duration. Wheat grains from two cultivars were irradiated by single laser pulses with a quasi-uniform irradiation and two fluences (2.5 and 5 J cm⁻²). The ablation flux was characterized by environmental scanning electron microscopy before measuring the removed material on cross-sections observed by confocal scanning laser microscopy. Specific image treatment was carried out to obtain the ablation flux (amount of removed matter per pulse). Pericarp, seed coat and aleurone layer were gradually ablated under the laser conditions used in this work. Their ablation thresholds were different and could be related to tissue cohesion. Specific behaviour of seed coat layer (8 μm) could be emphasised with this technique. Pulsed laser ablation could be a potential methodology to reveal indirectly wheat grain layer cohesion.     

家蝇饲养技术研究及蝇蛆在鳖养殖中的应用

试验结果表明：以麦麸、玉米粉混合饲料及猪粪育蛆，其饲料系数分别为１６７和２９３。以猪粪育蛆，麦麸和玉米粉用量减少近８０％，育蛆成本比前者降低６０％左右。以蛆饲喂出壳一个月内的稚鳖，其平均增重量约为饲喂鸡蛋黄稚鳖的３８倍。两组试验中，稚鳖平均增重量，经Ｔ测验，差异极显著。以猪粪育蛆，并以蛆饲喂稚鳖，既处理了猪粪，减少环境污染，又提高了猪粪的经济价值，值得在养殖业中推广应用。