Functional,digestibility, and antioxidant properties of brown and polished rice flour from traditional and new‐improved varieties grown in Sri Lanka

Sri Lankan traditional and improved rice varieties were processed into brown and polished rice flours. Samples were analyzed for AM, protein, lipid, total phenolic content, and antioxidant activity. Gelatinization and retrogradation properties were observed in the Rapid Visco Analyzer (RVA) and DSC. The AM content of the samples was high to intermediate (20 to 26%) except for one which was low (17%). Brown rice flour (BRF) samples had lower swelling power, lower RVA viscoamylograph profile, lower gel hardness, lower gelatinization enthalpy but higher gelatinization peak temperature and lower melting enthalpies of its retrograded AP relative to its corresponding polished rice flour (PRF) samples. The BRF showed a lower decrease in peak viscosity in the RVA viscoamylograph as compared to its PRF when treated with α‐amylase indicating inhibition potential. The traditional rice varieties had 68 to 86% higher total phenolic content (TPC) and 86 to 90% antioxidant activity in the BRF samples as compared to the improved varieties. A study on the antioxidant profile of the brown rice of the traditional rice varieties is being undertaken to explore their value as functional foods.     

Technological functionality of composite flours from sorghum,tapioca and cowpea

Composite flours from accessible raw materials may interest developing countries, cutting wheat import costs, bolstering domestic agriculture and boosting nutrition. Technological functionality (WHC and OHC, pasting, swelling and thermal properties) of composite tapioca, sprouted sorghum, cowpea and wheat flours (at 50%, 33% and 25% (w/w) flour basis) was evaluated. PCA revealed that, in a 50% w/w blend, sprouted sorghum and tapioca were technologically similar to wheat, and thus of interest when gluten's viscoelastic properties are not required (e.g. flatbread). Since cowpea flour can enhance nutrients, a flour from sprouted sorghum, tapioca and cowpea is preferable nutritionally and technologically, and potentially sustainable, its raw materials being available locally. Furthermore, PCA showed that composites of sprouted sorghum, tapioca, cowpea and wheat flours at 25% w/w offer a good compromise between technological and nutritional qualities, while reducing wheat imports and cassava post-harvest losses. These results may herald technologically satisfactory, nutritional, sustainable bakery products.     

Comparative Study on Functional,Rheological, Thermal,and Morphological Properties of Native and Modified Cereal Flours

Effect of extrusion on the functional, rheological, thermal, and morphological properties of the modified cereal flours from different cereals was assessed. Rice flour, wheat flour, and flour, in combination (rice: wheat, 50:50) were passed through twin screw extruder to obtain modified cereal flours at variable conditions (barrel temperature: 175 and 190°C, feed moisture: 14 and 16% and screw speed: 500 rpm). Functional properties (water absorption index, water solubility index, swelling index, and viscosity) improved in modified cereal flours as compared to the unmodified flours. Modified flours showed lower paste viscosity as compared to unmodified flours, which was a desirable property for modified flours to be utilized as a functionality ingredient in food products. Processed flours recorded higher onset (T_o), peak (T_p), and endset (T_e) temperature and showed higher enthalpy change (?H) than the raw cereal flours. Degree of gelatinization was higher in flours processed at higher barrel temperature and feed moisture. The morphological pattern of modified flours was determined by scanning electron microscopy. The starch surface of cereal flours (modified and unmodified) differed from each other with respect to their morphological pattern.     

苦荞-小麦混合粉流变学特性及烘焙特性研究

该文对苦荞小麦混合粉粉质特性、拉伸特性进行系统研究。随着苦荞粉比例增加,形成时间、稳定时间缩短,弱化度上升,评价值下降,拉伸参数均呈下降趋势;且苦荞粉比例越大,下降幅度越大。另外,面包烘焙实验表明,苦荞添加量为10％和20％时,苦荞面包尚有较好烘焙特性,添加量增至30％时,烘焙特性显著下降,添加量达40％或50％时,烘焙特性极差。     

绿豆-小麦混合粉的流变学和热力学特性研究

以小麦粉、绿豆粉为原料,研究绿豆-小麦混合粉面团的形成特性、流变学特性、热力学特性,为绿豆小麦粉复合食品的加工及品质控制提供参考。结果表明,添加绿豆粉对绿豆-小麦混合粉的物性有显著影响;随着绿豆粉添加量的增加,混合粉面团的吸水率、形成时间、稳定时间、评价值降低、弱化值增加;最大拉伸阻力、延伸度降低;热焓呈非线性降低,糊化温度增加;储能模量、损耗模量减小,黏弹性降低。     

板栗－小麦混合粉的流变学和热力学特性

以板栗全粉和小麦粉为原料,研究板栗-小麦混合粉面团的粉质特性、糊化特性、流变学特性和热力学特性。结果表明,添加板栗全粉对板栗-小麦混合粉的性质影响显著。随着板栗全粉添加量的增大,混合粉面团的粉质特性和糊化特性降低,糊化温度增加,热焓值减小;湿面筋含量、面筋指数、储能模量和损耗模量降低,说明加入板栗全粉使面团筋力减弱,抑制了淀粉的糊化过程,降低了面团的黏弹性。     

大豆粉-平菇粉-麦粉为基料的面条配方优化

通过研究平菇粉和大豆粉、小麦粉对面团热机械特性的影响,优化预混粉配方。首先,以平菇粉、大豆粉和小麦粉为原料,利用Mixolab混合实验仪研究添加平菇粉、大豆粉、食用胶及食盐对面团热机械特性的影响,优化混合粉的配方。接着,利用Mixolab的剖面图模式和测定面条的蒸煮特性验证混合粉的面条加工适性。结果表明:混合粉各成分的添加比列为平菇粉10%、大豆粉5.4%、食盐3%、黄原胶0.28%、魔芋胶0.12%、小麦粉81.2%。此混合粉的吸水率（由63.7%增加到72.3%）和稳定时间（由4.31 min增加到4.74 min）相对于未添加食盐和食用胶的混合粉有所提高。由此混合粉制备的面条其蛋白质、膳食纤维、赖氨酸含量分别增加了2.9 g/100 g、0.41 g/100 g、1.8 mg/g。因此,利用Mixolab可以优化混合粉的配方,并且优化的混合粉除在满足产品加工特性的基础上也较大程度地提高了面条的营养品质。     

Physicochemical,antioxidant properties and in vitro digestibility of wheat–purple rice flour mixtures

The physicochemical characteristics, antioxidant properties and in vitro digestibility of high‐antioxidant content flours made from different combinations of Thai purple rice flour and refined wheat flour from 25%, 50% to 75% (w/w) were investigated and these were compared with whole flour from purple rice and refined wheat flour. The increase in substitution levels of purple rice flour affected all the functional properties of flours, at the same time the levels of dietary fibre, protein digestibility and antioxidant compositions were also changed. The purple rice flour exerted a particularly strong effect on starch digestibility as the purple rice increased to 50% in the mixture. Moreover, purple rice flour showed lower amounts of rapidly digested starch (RDS), whereas slowly digested starch (SDS) of whole flour from purple rice and 75% substitution purple rice flour was found to be the highest for all samples. The in vitro starch digestibility of all samples also showed a positive correlation between dietary fibre and antioxidant compounds. Overall, the addition of purple rice flour improved the final nutritional properties, notably a lower predicted glycaemic index, and a higher antioxidant potential, which are two important nutritional properties for human health.     

Protein contents, physical and sensory properties of Nigerian snack foods (cake, chin-chin and puff-puff) prepared from cowpea – wheat flour blends

Some Nigerian snack foods, particularly cake, chin‐chin and puff‐puff, were prepared from blends of cowpea and wheat flours. The snack foods were evaluated for their protein content, physical and sensory characteristics. The latter included colour, flavor, texture and overall acceptability. All the snack foods showed higher protein content when compared with the 100% wheat flour based snack foods. The protein content increased with the increasing levels of cowpea flour in the blend. The physical properties of the supplemented snack foods were not adversely affected by supplementation with cowpea. Similarly, at all levels of cowpea supplementation, the sensory characteristics of the snack foods did not differ significantly (P > 0.05) from those of the 100% wheat flour based snack foods.     

香菇粉对小麦面团热机械学和动态流变学特性的影响研究

本试验通过测定不同比例的香菇粉和小麦粉混合粉的热机械学和动态流变学特性,研究香菇粉对小麦面团特性的影响。结果表明,香菇粉的添加使小麦面团的吸水率增大,面团的形成时间和稳定时间先下降后上升,相应的蛋白质弱化度先升高后降低。香菇粉的添加使小麦面团的峰值黏度和回生值均显著降低。动态流变学试验显示:香菇粉的添加使得小麦面团的黏弹特性发生了显著的变化,储能模量(G')与损失模量(G")均呈现先降低后升高的趋势。而tanδ随香菇粉比例的增大呈现了先略微升高后明显降低的趋势,表明了混合体系中分子交联的程度有所增加,弹性比例增大。     

Impact of brown foxtail millet (Setaria italica) flour on thermo-mechanical properties of flours from different rice varieties

The physical, functional and thermo-mechanical properties of rice flours prepared from long, round and medium rice grain and of foxtail millet (Setaria italica) flour were investigated. The impact of foxtail millet flour addition on the thermo-mechanical properties to the rice flours was also explored. Rice flour from long grain had higher amylose content (26.37%), while the rice flour from round grain had better hydration properties compared to the other rice flours. The dough from long grain rice flour exhibited higher starch gelatinisation temperature and cooking stability and lower starch retrogradation compared to the other investigated rice flours. Foxtail millet flour addition to the rice flours exerted a lower impact on the thermo-mechanical properties of the dough based on rice flour from long grain compared to the other investigated rice flours. These differences might be due to the differences in terms of starch properties and proximate composition of the flour samples.     

Contribution of the starch, protein, and lipid fractions to the physical, thermal, and structural properties of amaranth (Amaranthus caudatus) flour films

ABSTRACT:  Amaranth protein–lipid (PL) and protein (P) films were elaborated and compared with amaranth flour films in order to determine the contribution of the interactions between the biopolymer (starch and protein) and the lipids to the film properties. The films were made by the casting method, using the same glycerol concentration (0.9 g glycerol/100 g solution). A separation of the lipid fraction in the PL films and a polymorphic transformation of the corresponding fatty acids were observed by differential scanning calorimetry (DSC) and verified by an analysis of the microstructure by scanning electron microscopy (SEM). The flour films showed no separation of the lipid fraction, evidence that the lipids were strongly associated with the proteins and homogenously distributed throughout the starch network, contributing to the good mechanical properties when compared to the PL films and to the excellent barrier properties when compared to both the PL and P films. The protein-protein interactions also contributed to the mechanical properties of the flour films. The presence of proteins and lipids in the flour films had an important effect on film solubility, and also on the color and opacity of the films. This study showed that the flour film properties depended on the interactions formed by their polymers (starches and proteins) and by the lipid, on the distribution of these interactions within the film matrix and on the concentrations of each component in the film.     

Evolution of functional,thermal and pasting properties of sprouted whole durum wheat flour with sprouting time

This research investigated the evolution of functional, pasting and thermal properties of durum wheat (Triticum durum) with sprouting time. Particle size, flour and flour gel hydration properties (Water Holding Capacity (WHC), Swelling Volume (SV), Water Absorption Index (WAI), Water Solubility Index (WSI), Swelling Power (SP)), Oil Absorption Capacity (OAC), Pasting and thermal properties were evaluated on different sprouting time: 12, 24, 36, 48 and 72 h. Results showed that more than 12 h decreased significantly particle size, WHC(−14.8%), SV (−19%), SP (−14%) and WAI (−36.5%) while WSI (+383%) and OAC (+7.3%) increased. Pasting properties drastically decreased with sprouting time. DSC results showed a significant increase in onset temperature (T₀) (from 55.2 to 58.2 °C), peak temperature (T_p) (from 62.4 to 63.8 °C) while conclusion temperature T_c decreased (from 76 to 72.6 °C). Despite these changes, sprouted whole wheat flour could be suggested as an improver of some cereal products’ functionality.     

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。     

马铃薯-籼米粉特性及其挤压成型品质

为推进马铃薯主食化研究,将马铃薯全粉和籼米粉混合并通过螺杆挤压技术制备米粉。研究添加马铃薯全粉对籼米粉糊化、流变、凝胶质构、微观结构以及对米粉蒸煮、质构和色差等品质的影响。结果表明,与纯籼米粉相比,马铃薯全粉增加,混合粉糊化后的糊化特征参数、弹性模量、黏性模量、凝胶强度均降低,凝胶流动性更好,呈现较少、均匀程度相同的孔状结构,且连接较紧密。米粉的蒸煮时间、透射比亦降低,而吐浆值和断条率升高。米粉质构特征值呈降低趋势,与凝胶质构变化一致。添加20%马铃薯全粉能使米粉亮度值L显著减小,红值a显著增大;30%马铃薯全粉能使黄值b显著增大。综合各项指标,马铃薯全粉添加量在30%以内,米粉仍具有可接受的品质。     

TGase与谷朊粉添加对马铃薯全粉-小麦粉混合粉面团特性的影响

将不同量的谷氨酰胺转氨酶与谷朊粉添加到小麦面粉与马铃薯全粉混合粉（小麦面粉与马铃薯全粉之比为7:3）中,研究了混合粉的粉质特性、动态流变特性与糊化特性。结果表明,当谷氨酰胺转胺酶添加量不断增大时,混合粉面团吸水率、形成时间、稳定时间延长、弱化度逐渐减小,且弹性模量G'和粘性模量G″明显增大;峰值黏度、谷值黏度、最终黏度均逐渐增大,回生值逐渐减小;随着谷朊粉的含量增加,添加0.6 U/g谷氨酰胺转胺酶的混合粉其面团吸水率、形成时间、稳定时间、G'和G″、峰值黏度、谷值黏度、最终黏度、衰减值均逐渐增大,弱化度减小。在添加有0.6 U/g谷氨酰胺转氨酶的混合粉中添加8%的谷朊粉,混合粉面团的弱化度达到216±1.08 BU,衰减值达到534.2±54.5 cP,面团特性最佳。     

糯小麦粉添加量对配粉流变学特性及馒头品质的影响

将糯小麦粉与普通小麦粉进行梯度配粉,研究不同糯小麦粉添加量对配粉糊化黏度、粉质特性和面团流变学特性的影响;采用质构和感官评价相结合的方法评价其对馒头品质的影响,确定合适的糯小麦配粉比。结果表明：随着糯小麦粉添加量的增加,配粉的糊化温度、峰值黏度、衰减度和回生值等快速黏度分析参数均呈现下降趋势,尤其是回生值降低显著。配粉的吸水量随糯小麦粉添加量的增加逐渐增大,面团的形成时间和稳定时间缩短,粉质指数降低;但当添加量增加至25.0%时,粉质特性各指标均产生显著性改变。不同配粉面团随着醒发时间的延长,面团拉伸曲线面积、拉伸阻力和拉伸比等指标均呈现一定的增大趋势,但延伸度却随醒发时间延长而降低。糯小麦粉配粉比例对馒头的质构和感官特性具有较大影响,适宜的糯小麦粉配粉比为20.0%～30.0%,25.0%配粉比使馒头具有较好的质构,感官总评分达到最大值。