不同储藏时间米糠制备膳食纤维对米粉糊化和凝胶性质的影响

将米糠储藏0、1、3、5、10 d后制备的米糠不溶性膳食纤维(rice bran insoluble dietary fiber,RBIDF)添加到米粉中,研究不同储藏时间米糠制备的RBIDF对米粉糊化和凝胶性质的影响。结果表明,当RBIDF添加量相同时,随着米糠储藏时间的延长,米粉的峰值黏度呈先上升后略微下降的趋势,在米糠储藏第5天时达到最大值,回生值逐渐上升,峰值时间和糊化温度先下降后上升,分别在米糠储藏5 d和3 d达到最小值;储能模量在米粉凝胶形成阶段和米粉凝胶形成后阶段都呈上升趋势,损耗角正切在米粉凝胶形成后阶段先减小后增大,在米糠储藏5 d达到最小值;硬度、回复性、胶着性、咀嚼度先增大后减小,黏附性先减小后增大,均在米糠储藏3 d达到极值。相关性分析结果表明,米糠毛油酸值与米粉的峰值黏度呈显著(P 0. 05)正相关,与峰值时间和糊化温度呈极显著(P 0. 01)负相关,与回生值和米糠储藏时间呈极显著(P 0. 01)正相关。     

Adding Rice Starch to Hard Wheat Flour for Improving its Dough Properties and Baking Quality

Results show that the addition of rice starch to hard wheat flour improves the dough properties and baking quality as demonstrated by the tests and the readings of Farinograph, Extensograph and Amylograph as well as increases the reducing sugars, acidity and the volume of the produced bread. Experiments proved that best results were observed when rice starch was added to hard wheat flour at 6 to 8%.     

裸燕麦米和燕麦粉加工所得麸皮中β-葡聚糖和酚酸的分布

选取具有代表性的裸燕麦品种,分析燕麦麸皮和胚乳所占的比例和微观结构特征;同时分析β-葡聚糖和酚酸在燕麦麸皮（果皮、种皮＋糊粉层）和胚乳中的分布,并验证了现有燕麦米和燕麦粉主流加工方式的适宜程度。结果表明,在所选裸燕麦品种中,β-葡聚糖均富集在麸皮中,质量分数达8.57%,约是胚乳中含量的4.5?倍;麸皮中p-香豆酸和阿魏酸的含量分别达0.099?mg/g和1.00?mg/g,分别是胚乳中相应含量的24?倍和48?倍;在麸皮中,果皮中p-香豆酸和阿魏酸含量分别约为种皮＋糊粉层中的13?倍和2.7?倍。研磨制燕麦米所得第2道麸皮中,β-葡聚糖质量分数平均为1.7%,远小于麸皮中的平均含量,加工程度适宜;而燕麦制粉所得第4道和第5道麸皮,β-葡聚糖质量分数达6.73%和7.80%,接近糊粉层中β-葡聚糖含量,加工过度。综上可知,利用分析燕麦加工所得麸皮中葡聚糖和酚酸含量,可初步判定燕麦米和燕麦粉的加工程度,为其加工提供技术支撑。     

Effect of Wheat Bran,Coarse Wheat Flour,and Rice Flour on the Instrumental Texture of Cookies

Abstract

The effect of replacing wheat flour with wheat bran (0–10%), coarse wheat flour (0–20%) or with rice flour (0–20%) on the quality of cookies was studied. The cookie dough was subjected to Instrumental Texture Profile Analysis in order to determine dough cohesiveness and adhesiveness. After baking spread factor, puncture force and fracture strength of the cookies was also determined. The control dough had cohesiveness and adhesiveness values of 0.279 and 13.6 N s whereas control cookies had puncture force and fracture strength of 90.84 N and 100.16 N. Wheat bran increased dough cohesiveness and adhesiveness whereas coarse wheat flour had the opposite effect. Increasing levels of rice flour decreased cohesiveness but increased adhesiveness. Wheat bran and rice flour lowered the spread factor where as coarse wheat flour increased spread factor. Coarse wheat flour and rice flour lowered the fracture strength where as wheat bran increased fracture strength. Sensory evaluation revealed that increasing levels of wheat bran lowered the overall acceptability whereas rice flour and coarse wheat flour improved sensory scores.     

Functional Properties of Dry Milled Fractions From Wild Oats (Avena fatua L.)

When processed into groats, wild oats provided meal, bran and flour fractions which contained 22, 28 and 18% protein, respectively. While nitrogen solubilities were low due to the steam treatments used to inactivate lipase, water hydration capacities of the wild oat products were high. Oil absorption characteristics of the bran were more than twice those of the flour but oil emulsions formed with wild oat products were poor. Starch contents of the meals and flours were 55 and 70%, respectively, and their Visco/Amylograph curves were characterized by low initial pasting temperatures, high peak viscosities at 95°C and setback values that were intermediate to those of corn flour.     

Dough properties and breadmaking qualities of whole waxy wheat flour and effects of additional enzymes

BACKGROUND: Waxy wheat, a new kind of genetically back‐crossed wheat, was applied to make whole bread in this study. Dough properties and bread quality of the whole waxy wheat flour, which was milled from 100% whole grains containing bran and germ, were determined. RESULTS: Whole waxy wheat had lower protein and lipid contents but higher dietary fiber content than whole regular wheat flour. Pasting temperature and viscosity of the whole waxy wheat flour were significantly lower than those of the whole regular wheat. However, the white wheat flour milled from wheat grains with 48% recovery had significantly higher peak viscosity than the whole waxy wheat. Bread made from the whole waxy wheat flour was significantly softer than that from the whole regular wheat flour during storage. However, bread made from whole waxy wheat had significantly lower specific volume than that from the white waxy flour because of the high amount of dietary fiber. Addition of cellulase increased paste viscosity, lowered dough mixing properties and reduced the firmness of the bread. The addition of pentosanase also increased paste viscosity, lowered dough mixing properties, improved loaf volume of bread but increased the firmness of breadcrumbs, while the addition of α‐amylase only increased final viscosity of flour and did not affect dough properties and bread qualities of whole waxy wheat flour. CONCLUSION: As a result, waxy wheat shows superior properties for making whole breads. Additional enzymes are also necessary to improve bread quality and nutritive values of whole waxy bread. Copyright © 2007 Society of Chemical Industry     

添加挤压米糠粉对面包粉流变学特性影响的研究

米糠中含有多种营养成分,对人体具有重要的营养及保健功能,但其会影响食品的品质,需改性加工后方可适量添加到食品中。将挤压改性加工后的米糠粉以不同比例添加到面包粉中形成混合粉,并测试了混合粉的粉质及拉伸特性,以探讨米糠对面包粉品质的影响。结果表明:米糠的添加对面包粉的品质具有一定程度的影响,添加量越高影响越大,并通过米糠面包的物性测试对上述结果进行了验证,最终确定了适宜制作面包的挤压米糠粉添加量为15%。     

Investigation of Dry‐Heated Hard and Soft Wheat Flour

The Amylograph profile of dry‐heated (120°C, 120 min) wheat flour showed a drastic change, i.e. an earlier onset time and higher peak viscosity than that of a control. However, no difference in the size of the starch granules was observed between dry‐heated and normal starch at every temperature. Wheat flour was fractionated with acetic acid, and the separated prime starch (PS) and tailings (T) fractions were dry‐heated at 120°C for 30, 60, 90, and 120 min, respectively. There was almost no difference in the RVA and DSC profiles between PS and dry‐heated PS, and T and dry‐heated T fractions, i.e., dry heating of wheat flour did not change the structures of starch that would be related to onset time and peak viscosity in the Amylograph profile. We thus excluded the water solubles (WS) fractions from control and dry‐heated wheat flour, but the effect of dry heating on the Amylograph profile was not lost. Next, the gluten (G) fraction was excluded following WS fraction from these wheat flours, and Amylograph tests were performed. The Amylograph profiles in both wheat flours were almost coincidental, which showed that the G fraction in dry‐heated wheat flour caused the earlier onset time and higher peak viscosity.     

Water Holding Capacity of Hemicelluloses from Fruits, Vegetables and Wheat Bran

The water-holding capacities of freeze-dried bean, cabbage, lettuce, onion, peach, pear, pumpkin, tomato, wheat bran and their hemicelluloses were determined by the centrifugation method. Cabbage had the greatest water-holding capacity at 35.8g of water per gram of dry food; bran the lowest at 5.2g water per gram. The waterholding capacity (WHC) of the hemicelluloses from fruits and vegetables varied considerably from 3.3 g/g in beans to 12.0 g/g from cabbage. Hemicelluloses extracted from wheat bran showed a marked increase in WHC from 5.2 g/g of water per gram of‘whole’bran to 22.8 g/g for hemicellulose. This decreased to 15.3g of water bound by hemicellulose that had been extracted after chlorite delignification. WHC of hemicelluloses from wheat bran and cabbage may account for their ability to increase stool weight.     

银杏-籼米粉特性及其挤压粉丝的品质研究

为了加大银杏果的利用率,将银杏粉和籼米粉按照一定比例混合并制作挤压米粉丝。研究了银杏粉添加对米粉糊化特性、流变特性、凝胶质构和微观结构等理化特性的影响。利用挤压加工技术生产挤压银杏米粉丝,研究了银杏粉添加对挤压粉丝蒸煮特性、质构特性以及色泽等品质特性的影响。结果表明,随着银杏粉添加量的增加,样品糊化后的凝胶呈现出较多大小、均匀程度不同的孔状结构。与原籼米粉相比,混合粉的峰值黏度、最低黏度、崩解值、回生值、弹性模量、黏性模量、凝胶强度随银杏粉添加量的增加而降低,糊化温度略有升高;随着银杏粉添加量的增加,挤压米粉丝的蒸煮时间、蒸煮损失和断条率分别从22. 23 min、6. 93%、4. 44%增至24. 27 min、15. 29%、13. 33%,挤压米粉丝的硬度、弹性和咀嚼度分别从3 469 g、0. 96、1 866 g下降至2 529 g、0. 84、1 068 g。但银杏粉添加量在30%以内,银杏米粉丝仍具有可接受的品质。     

Cooperative Test on Amylography of Milled-Rice Flour for Pasting Viscosity and Starch Gelatinization Temperature

An ICC cooperative test on Amylograph viscosity of milled-rice flour involving 11 laboratories and 4 contrasting rice samples was undertaken to determine the reproducibility of the method. The highest contribution to total variance was from sample followed by laboratory and then sample x laboratory. Only 2 of 9 laboratories showed similar peak viscosities on the samples, only 3 of 8 laboratories had similar cooked paste final viscosities, but none of 7 laboratories had similar cooled paste final viscosities using preground flour and a common method. Use of individual mills to prepare flour for the common method and use of laboratory method with preground flours increased variance due to laboratory and reduced the contribution of sample. Final gelatinization temperature of starch may be readily estimated from the apparent temperature of 20 BU intercept of the Amylograph curve of 20% preground paste from the results of 5 laboratories with 700 g · cm cartridge.     

Effect of milling on colour and nutritional properties of rice

Brown rice (long-grain variety Puntal) was abrasively milled (0–100 s) to various degrees of milling (DOM, 0–25%). The non-linear relationship between milling time and DOM indicated a variability in hardness within the different rice fractions. The hardness of the bran layers increased from outer to inner bran layers, while the different endosperm fractions were of comparable hardness. The colour parameters L^*, a^* and b^* and extinction measurements of water-saturated butanol extracts of flour, from rice with different DOM, indicated that bran contained much more yellow and red pigment than endosperm. The levels of yellow and red pigment decreased from the surface of the brown rice to the middle endosperm (DOM = 15%). Once bran (DOM = 9%) and outer endosperm (additional DOM = 6%) were removed, the yellowness and redness of the middle endosperm of the raw rice remained constant, indicating that the pigments were uniformly distributed in the middle endosperm. Cooking of rice containing residual bran layers (DOM < 9%) increased rice brightness (L^*) and decreased its redness (a^*) and yellowness (b^*), as expected from a dilution effect resulting from the uptake of water, as well as from leaching of pigments in the cooking water and diffusion of bran pigments to the endosperm. Cooking of rices with DOM > 9% resulted in products of constant brightness and redness but with yellowness which decreased as a function of DOM. Proteins, minerals and starch were not uniformly distributed in the brown rice kernel. The endosperm (DOM > 9%), contained most of the rice kernel proteins (84.2%), and proteins were mostly concentrated in the outer endosperm (9% < DOM < 15%). Bran (0% < DOM < 9%) contained most of the minerals (61.0%), and starch (84.6%) was concentrated in the core endosperm fraction (DOM 25%).     

米糠和麦麸膳食纤维的制备研究

探讨了米糠半纤维素和麦麸膳食纤维的提取工艺。结果表明 :( 1 )料液比 1∶1 0 ,6 0℃浸提 3h ,米糠水溶性半纤维素提取率 1 38% ;( 2 )料液比 1∶1 0 ,0 5mol/L的NaOH 2 5℃浸提 3h ,米糠碱溶性半纤维素提取率 8 86 % ;( 3) 0 6 %的NaOH ,α 淀粉酶加入量 0 4% ,70℃浸提 1 5h ,麦麸膳食纤维提取率达 6 6 2 7%。     

Physicochemical Properties of Starch of Intermediate-Amylose and Waxy Rices Differing in Grain Quality

Starches from two crops of 7 intermediate-amylose and 7 waxy milled rices differing in eating qualities were characterized. Among the nonwaxy rice starches, those of softer cooked rice had gelatinization temperature of ≥ 70°C, medium to soft gel (110 mg/2 ml) consistency, low alkali viscograph peak viscosity, and greater Amylograph breakdown and lower Amylograph setback and consistency than low gelatinization temperature starches. Among waxy starches, gels of low gelatinization temperature samples had greater freeze-thaw stability than gels of high gelatinization temperature samples. A 12% paste gave better differentiation in Amylograph viscosity than 10% paste of intermediate-amylose milled rice. Water-extractable substances that suppressed the Amylograph viscosity of milled waxy rices were lipids and polysaccharides.     

不同杂粮添加对籼米粉粉质特性及挤压米粉品质特性的影响

本文选择绿豆、荞麦、高粱、薏米四种杂粮分别添加到籼米粉中,替代比例为25%。通过快速黏度测定仪、动态流变仪、质构仪和扫描电镜,研究了杂粮添加对米粉糊化特性、流变特性、凝胶质构和微观结构等特性的影响。利用挤压重组技术生产挤压杂粮米粉,研究了杂粮添加对挤压米粉蒸煮特性、质构特性的影响。结果表明,杂粮粉与籼米粉混合后,荞麦混合粉在淀粉糊化过程中表现出最高的峰值黏度和最终黏度,分别为4241和4705 cP,而薏米混合粉峰值黏度和回生值最低,分别为2438和1369 cP;添加杂粮后的凝胶结构呈现出较多的孔状,其中荞麦粉混合凝胶的硬度和弹性值最大,分别为16.60 g和0.89;添加杂粮后,挤压米粉的膨胀率、蒸煮损失、断条率均有所增加;添加荞麦粉后米粉的质构特性接近籼米米粉,而添加薏米粉的米粉质构特征值表明挤压米粉的品质显著降低(p<0.05)。利用挤压技术开发挤压杂粮米粉不仅可以提高米粉的营养价值,同时也有助于推动传统主食食品米粉的工业化发展进程。     

挤压与汽爆麦麸添加对小麦粉糊化特性的影响

以低筋、中筋和高筋小麦粉为材料,考察原麦麸、挤压麦麸和汽爆麦麸的添加量、粒度对小麦粉糊化特性的影响。结果表明：在0.178～0.250 mm粒度范围内,随着麦麸添加量的增加,小麦粉峰值黏度、最终黏度和回生值都显著性下降（P＜0.05）,而糊化温度和糊化起始时间则呈现二次曲线增加的趋势。汽爆麦麸和挤压麦麸对于小麦粉糊化起始时间和糊化温度的提升效果明显高于原麦麸。随着原麦麸粒径的减小,中筋、高筋小麦粉的峰值黏度、最终黏度和回生值均呈现先降低再升高的变化趋势,而3 种麦麸糊化温度和糊化起始时间呈现下降趋势。在0.150～0.420 mm粒度范围内时,原麦麸的粒度对低筋小麦粉回生值的影响具有显著差异（P＜0.05）;挤压麦麸和汽爆麦麸的粒度对中筋小麦粉峰值黏度的影响无显著差异（P＞0.05）;原麦麸和汽爆麦麸的粒度对高筋小麦粉峰值黏度的影响具有显著差异（P＜0.05）。     

蛋清蛋白添加对籼米-绿豆粉粉质特性及挤压米粉丝品质特性的影响

将籼米粉、绿豆粉和蛋清蛋白粉按照一定的比例复配,开发高纤维含量的杂粮米粉丝。研究了绿豆和蛋清蛋白的添加对米粉糊化特性、流变特性以及挤压米粉丝微观结构、蒸煮特性和质构等品质特性的影响。结果显示:添加一定量的绿豆粉和蛋清蛋白粉后,混合粉的峰值黏度、最低黏度、最终黏度、回生值、弹性模量、黏性模量均逐渐下降。随着绿豆粉的添加(25%,50%),米粉的蒸煮时间、断条率、蒸煮损失和吸水率均上升,硬度降低,表明米粉的品质显著降低,由扫描电镜图可以发现,加了绿豆粉之后米粉截面变得越来越粗糙,裂纹和孔洞明显增多。但当加入7.5%的蛋清蛋白后,米粉的蒸煮时间、蒸煮损失和断条率均下降,质构特性有一定程度的改善,表明蛋清蛋白良好的凝胶特性有助于提升高纤维含量挤压米粉丝的品质。     

Efficacy of diatomaceous earth and methoprene, alone and in combination, against Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae) in rough rice

Combination treatments of diatomaceous earth (DE) (Protect-It^®) and the insect growth regulator (IGR) methoprene (Diacon^® II) were evaluated against Rhyzopertha dominica (F.), the lesser grain borer, on stored rough rice. Application rates of DE and methoprene ranged from 0 to 500 ppm and 0 to 1 ppm, respectively, in 25 treatment combinations. Tests were conducted by exposing 20 adults for 2 weeks at 32 °C and 75% relative humidity on single varieties of long-, short-, and medium-grain rough rice, removing adults, and holding the rice for 8 weeks at the same conditions to collect F₁ progeny. In the absence of methoprene, mortality of exposed adults increased as the concentration of DE increased, but even at the highest rate of 500 ppm, mortality was only 57.5±12% and 58.8±9.7% in long and medium-grain rice, respectively, and 26.3±4.7% in short-grain rice. Mortality of R. dominica exposed on short-grain rice was lower than mortality on long-and medium-grain rice at several combinations with 375 and 500 ppm DE. There was also an unexpected increase in adult mortality with the addition of methoprene so that at 1 ppm methoprene and 500 ppm DE, mortality in long-, medium-, and short-grain rice was 77.5±9.0%, 77.5±10.0%, and 58.5±3.0%, respectively. In the absence of methoprene, progeny produced on long- and short-grain rice ranged from 48.0±21.2 to 87.2±9.0, compared to 16.5±5.5 to 33.5±8.6 progeny produced on medium-grain rice. With the inclusion of methoprene there were few progeny produced in any of the treatment combinations, and the overall average was 0.6±0.3. Similarly, with no methoprene the range of insect-damaged kernels (IDK) was 5.2±2.7 to 12.2±3.1%, but with methoprene the overall average was reduced to 1.8±0.2%. While control of R. dominica was somewhat limited with DE, the differences among rice varieties seems to indicate that the specific type and possibly variety of rough rice may influence mortality and reproduction of R. dominica exposed to DE. With methoprene, progeny production was greatly suppressed regardless of DE concentration, but combining DE with methoprene would give some measure of adult control.     

米糠膳食纤维的制备与性能研究

将新鲜米糠脱脂后，分别用葡萄糖淀粉酶和木瓜蛋白酶除去淀粉和蛋白质，以4％的NaOH溶液提取半纤维素，得到10％的半纤维素A和2％的半纤维素B粗产品，多糖总量分别为86．38％和92．07％，非碱提物除木质素后，得到7％的纤维素．对它们的性能进行了分析，研究表明，在持水力、膨胀力和粘度方面，半纤维素B均优于半纤维素A及纤维素。     

Rheological properties of rice flour treated with mild solutions of citric acid

Effects of milling methods and organic acids treatments on rheological properties of rice flour were investigated. The average particle-size of wet-milled rice flour was lower and showed lower pasting temperature, peak viscosity, and storage modulus values than those of dry-milled rice flour. Wet-milled rice flour treated with citric acid showed significantly low viscosity and viscoelastic properties, as the concentration of citric acid increased, whereas wet-milled rice flour treated with acetic acid was not significantly affected by the acetic acid concentration. Rheological property of baekseolgi (Korean rice cake) made with wet-milled citric-acid-treated rice flour showed a similar trend in viscoelasticity, wherein citric acid treatment lowered the hardness of the rice. However, cohesiveness increased with increasing citric acid concentration. Overall, milling method affected the particle size, which influenced the viscosity and heat stability, whereas citric acid treatment affected the rheological properties of rice flour. These results are expected to contribute to the development of an appropriate method for rice flour application.