Extrusion cooking properties of white and coloured rice varieties with different amylose content

Five white and coloured rice varieties with different AM contents (long grain rice: 34%, Thai Jasmine rice: 15%, glutinous rice: 7%, red rice: 18% and black rice: 5%) were pregelatinised using a twin‐screw extruder at a barrel temperature of 150°C and two levels of feed moisture (12 and 16%). The correlation of AM content to water absorption index (WAI), water solubility index (WSI), starting viscosity, hot viscosity and final viscosity of the five rice extrudates were determined. Total anthocyanin content (TAC), total phenolic content (TPC) and antioxidant activity of extrudates were analysed by spectrophotometric methods. AM content was positively correlated to WAI and final viscosity. High AM content of the rice varieties resulted in high WAI and high final viscosity of extrudates. In addition, higher feed moisture content (16%) increased WAI and pasting properties of rice extrudates, but decreased WSI. Extrusion cooking reduced TAC, TPC and antioxidant properties, but the remaining values were high enough to suggest a further use for (functional) food production.     

鹰嘴豆、饭豆、绿豆淀粉性质的比较

以鹰嘴豆、饭豆、绿豆淀粉为对象,研究了不同豆类淀粉的糊化性、膨胀度、溶解度、淀粉-碘复合物的可见光谱、淀粉糊的透明度、冻融稳定性、凝沉性以及沉降体积等性质。结果表明:绿豆淀粉的成糊温度和峰黏度最高,而鹰嘴豆淀粉的热糊稳定性和冷糊稳定性最好;3种淀粉的膨胀度和溶解度均随温度的升高而增加,并且淀粉碘复合物可见光光谱的最大吸收波长都在620 nm左右。绿豆淀粉糊的透明度、冻融稳定性和凝沉性最好,沉降体积最大。     

三种杂豆淀粉理化特性的比较

以豇豆(Vigna unguiculata (L.) Walp.)、小黑芸豆(Phaseolus vulgaris L.)和小扁豆(Lens culinaris M.)为材料,采用湿磨法提取淀粉,以马铃薯淀粉和玉米淀粉作对照,对淀粉理化性质进行比较研究。结果表明,豇豆、小黑芸豆和小扁豆淀粉颗粒多为肾形,少数圆形,且偏光十字明显,表观直链淀粉含量分别为34.98%、45.35% 和37.24%。3 种淀粉的膨胀度和溶解度均随温度升高而增加,起糊温度在72.9～77.0℃之间,小黑芸豆淀粉起糊温度最高,峰值黏度、破损值、最终黏度和回生值最低。豇豆淀粉糊化特性与小黑芸豆淀粉相反,起糊温度较低,峰值黏度、破损值、最终黏度和回生值最高。3 种豆类淀粉To、Tp 和Tc 具有显著性差异,但焓值差异不显著,焓值大小顺序为小扁豆淀粉＞豇豆淀粉＞小黑芸豆淀粉。     

复配粉理化性质与米线质构性质关系的研究

将粳米粉与绿豆淀粉按照一定比例进行混合,得到粳米粉和绿豆淀粉的复配粉体系,并测定了复配粉体系的溶胀性质、糊化性质、凝胶质构性质和拉伸性质,研究了复配米粉体系的拉伸性质与米线质构性质的关系。结果表明:随着绿豆淀粉添加量比例的增加,复配米粉体系的总直链淀粉含量、可溶性直链淀粉含量和不溶性直链淀粉含量明显增加,峰值黏度、谷值黏度、末值黏度、硬度也显著性增加,咀嚼性、拉伸强度和表观弹性模量显著增加,85℃下的溶解度和膨润力显著上升;糊化温度显著降低;衰减值和回生值分别比粳米粉高了33.73 RVU和50.60 RVU;与单一体系相比,由复配粉体系制成的米线呈现较好的硬度、弹性、韧性、蒸煮性和物理性质。当绿豆淀粉∶粳米粉为1∶1时,其制得的米粉的质构性质最好。     

普鲁兰多糖对绿豆淀粉功能特性的影响

以资源丰富的绿豆淀粉为基材,按照不同比例与普鲁兰多糖共混,对混合物的功能特性进行了研究。结果表明:普鲁兰多糖可以降低绿豆淀粉的峰黏度、谷黏度、终黏度、稀懈值和回凝值,并且在一定范围内,这种变化随着普鲁兰多糖质量分数的增加而增大。另外,普鲁兰多糖的添加提高了绿豆淀粉的糊化温度,使其糊化受到抑制作用,且当普鲁兰多糖与绿豆淀粉的质量比达到2∶5时,这种抑制作用开始达到极显著水平。少量添加普鲁兰多糖后,绿豆淀粉老化的焓变值大大降低,但当普鲁兰多糖与绿豆淀粉的比例大于1∶6时这种抑制作用变缓。普鲁兰多糖可以增强绿豆淀粉的硬度、黏着性、弹性和胶凝性,而逐渐减小其黏聚性。     

挤压改性绿豆粉对小麦粉加工及其面条品质特性的影响

研究了添加挤压改性绿豆粉对挤压改性绿豆-小麦混合粉粉质特性、面团流变特性和所制备面条品质的影响。首先采用双螺杆挤压机处理绿豆粉,随后将挤压改性绿豆粉以不同添加量(10%~60%)添至小麦粉中,制备面条。然后采用粉质拉伸仪、RVA黏度仪、流变和质构仪对混合粉的粉特性、面团流变性能以及面条的质构特性进行分析。结果表明,随着挤压改性绿豆粉添加量的增加,绿豆-小麦混合粉面团的形成时间、稳定时间、粉质质量指数急剧下降,混合粉的粉质特性明显降低,且与小麦粉相比,混合粉的起始糊化温度、峰值黏度、谷值黏度、最终黏度、崩解值及回生值呈明显的下降趋势;随着挤压改性绿豆粉添加量的增加,混合粉面团的G'和G″降低,面团的网络结构受到破坏;对于挤压改性绿豆-小麦混合面条,随着挤压改性绿豆粉添加量的增加(<40%时),其干物质吸水率和损失率有所提高,蒸煮面条的硬度、弹性、胶粘性、咀嚼性和回复性有所降低,综合感官评分降低,当挤压改性绿豆粉添加量≤ 20%时,整体可接受度接近小麦面条。最后分析三者之间的相关性发现,挤压改性绿豆粉的添加量、挤压改性绿豆-小麦混合粉的粉质特性、黏度特性与其制作面条的品质有明显的相关性。综上所述,挤压改性绿豆粉的添加改变了小麦面团的特性和面条的品质,其添加量不宜超过20%。     

蛹虫草复合谷物杂粮膨化产品的工艺优化及糊化特性

目的：采用双螺杆挤压工艺制备蛹虫草复合谷物杂粮膨化产品,并研究蛹虫草对谷物杂粮膨化产品淀粉糊化特性的影响。方法：以大米粉、糯米粉、薏米粉、红豆粉、黄豆粉、蛹虫草粉为原料,按照一定比例混合制成蛹虫草复合谷物杂粮粉进行挤压膨化实验,并在单因素试验的基础上,选择物料水分含量、螺杆转速、进料速率、挤压温度为影响因素,产品径向膨化率、糊化度、水分含量、吸水性和水溶性指数为指标,设计正交试验,用极差分析法优化出蛹虫草复合谷物杂粮膨化产品的最佳工艺,并利用快速黏度仪测定谷物杂粮膨化产品和蛹虫草复合谷物杂粮膨化产品的淀粉糊化特性。结果：蛹虫草复合谷物杂粮膨化产品的最优工艺参数为物料水分含量16%、螺杆转速180 r/min、机筒的5 段挤压温度80-90-120-140-165 ℃、进料速率15 r/min,此时蛹虫草复合谷物杂粮膨化产品的径向膨化率、糊化度、水分含量、水溶性和吸水性指数分别为3.015、84.32%、6.11%、29.65%、416.39%;与谷物杂粮膨化产品相比,蛹虫草复合谷物杂粮膨化产品峰值黏度、保持黏度、最终黏度、回生值显著下降。结论：蛹虫草复合谷物杂粮膨化产品挤压工艺可行,添加蛹虫草能够显著降低谷物杂粮膨化产品的糊化特征值,并抑制其淀粉分子的回生或重排。     

烘焙和喷雾干燥对紫米粉特性和结构的影响

研究烘焙和喷雾干燥处理对紫米粉色泽、糊化及热特性的影响。结果表明:烘焙尽管对样品的短程有序结构及蛋白质二级结构影响不显著,但由于引起淀粉颗粒部分凝胶化及膨化,样品的结晶度及峰值黏度、最终黏度、崩解值、回生值等糊化相关黏度参数和热焓值均降低,而糊化温度升高;喷雾干燥不仅降低了样品的结晶度和粒径,也引起蛋白质部分α-螺旋和β-折叠结构转变β-转角结构,进而使样品的峰值黏度、谷值黏度、最终黏度、峰值时间及糊化温度均略有升高,而崩解值和回生值及热焓值略有降低;烘焙处理紫米粉的色泽较暗淡,而喷雾干燥样品的色泽更鲜亮。总之,2种热处理方式尽管均引起紫米粉中淀粉发生部分凝胶化,但对样品的色泽和物化特性的影响效果明显不同。     

Physicochemical characterisation of corn extrudates prepared with varying levels of beetroot (Beta vulgaris) at different extrusion temperatures

This study examines the effect of beetroot powder (BRP) incorporation (0%, 5%, 10% and 15%) at different extrusion temperatures (125, 150 and 175 °C) on the physicochemical, antioxidant and sensory properties of corn grit (CG) extrudates. BRP showed higher values of total phenolic content (TPC = 9095 μg GAE g^?1) and free radical inhibition (ABTS = 6.5 μm trolox mg^?1 and DPPH = 7.9 μm trolox mg^?1) than CG (1346 μg GAE g^?1, 1.5 μm trolox mg^?1 and 2.2 μm trolox mg^?1, respectively). Pasting viscosity (peak, breakdown and final) decreased, while pasting temperature of CG increased with the level of BRP incorporation. Analyses of the extrudates showed an increase in redness, bulk density, hardness, TPC, free radical inhibition, total dietary fibre (TDF) and a decrease in water absorption index (WAI), water solubility index (WSI), expansion ratio and oil uptake with the increase in the level of BRP incorporation. On the other hand, higher extrusion temperature increased porosity, WAI, WSI, oil uptake but decreased redness, bulk density, hardness and TPC.     

Effect of ozone treatment on physicochemical properties of waxy rice flour and waxy rice starch

The effect of ozone treatment on physicochemical properties of waxy rice flour and waxy rice starch was investigated. Results showed that ozone treatment increased the pasting viscosity of waxy rice flour. Compared with untreated waxy rice flour, the peak viscosities of waxy rice flour for 0.5, 1 and 2 h of ozone treatments were increased by 27.4%, 32.8% and 45.5%, respectively. The alpha‐amylase in waxy rice flour was inactivated during the treatment. The gelatinisation temperature and enthalpy of waxy rice flour were kept unchanged after the treatment. For waxy rice starch, pasting viscosity, swelling power and molecular weight were increased after 0.5 h of treatment, but decreased as treatment time extended. The ozone treatment decreased gelatinisation temperature and enthalpy of waxy rice starch.     

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。     

Rheology and tribology properties of cereal and legume flour paste from different botanical origins

Paste made from eight types of cereal grains (low fiber containing grains [LF grains]: rice, sticky rice, black rice, and millet; and high fiber containing grains [HF grains]: wheat, buckwheat, oat, and barley), and four types of legumes (soybean, red bean, kidney bean, and mung bean), were studied in terms of particle size, rheological, and tribological properties. Sticky rice and soybean pastes showed lower yield stress, viscosity and consistency coefficient than other pastes. Most cereal pastes showed a major peak at approximately 160 µm except for oat and barley, while legume pastes showed mono modal profiles except for soybean. Tribological results showed that starch tended to develop type A friction profiles, showing a typical Stribeck curve; bran/fiber tended to develop type B profiles, showing an ascent curve with clear onset of hydrodynamic regime; protein and lipids promoted type C profiles, showing a flat plateau shaped curve. Water soluble polysaccharides in grains or legumes could improve the paste lubrication. In general, 5% of the black rice paste and sticky rice in the LF grain group, and the soybean paste in the legume group, showed a low friction coefficient (μ) in the entire entrainment speed range; barley paste and oat paste in the HF grain group showed relatively low μ at low entrainment speed (0.5 mm/s) and medium entrainment speed (5 and 10 mm/s), respectively.     

模糊数学评定优化方便八宝粥配方的研究

为优化方便八宝粥的制作配方,在基础配方红小豆5g、绿豆3g、花芸豆3g、莲子2g和花生仁2g条件下,以小米添加量、黑米添加量、熟化糯米粉添加量及白砂糖的添加量为感官质量影响因素,模糊感官综合评定得分为考察指标,运用L9(34)正交试验优化配方设计。结果表明:小米添加量和黑香米添加量与模糊感官评分相关关系差异极显著(p0.001),熟化糯米粉添加量和白砂糖添加量差异显著(p0.05);方便八宝粥的最佳配方为:小米添加量为25g、黑香米添加量为10g、熟化糯米粉添加量为1.5g和白砂糖添加量为3.5g,在此工艺配方条件下制作的方便八宝粥的模糊感官评定得分为95.4分。     

天津主要市售谷物的真菌污染状况调查

对天津市售大米、小米、黄米、黑米、江米、西米、泰国香米、大薏仁米、大麦仁、红豆、绿豆、大豆和玉米渣等13种市售谷物进行真菌污染调查。调查表明,市售谷物中真菌平均侵染率37.0%,其中泰国香米、小米、江米、黑米和黄豆等污染较轻,其侵染率明显低于大米、大薏仁米和红豆。米类谷物中的主要污染真菌为青霉、曲霉和交链孢霉,大豆中的优势菌为曲霉,其他豆类的优势污染菌为交链孢菌,玉米渣中主要为酵母菌和曲霉。     

Chemical,Functional and Pasting Properties of Defatted Starches from Cowpea and Soybean and Application in Stiff Porridge Preparation

The effects of defatting on the chemical, functional and pasting properties of starches from cowpea and soybean and their application in stiff porridge preparation were studied. Conventional cassava starch served as standard. Defatting of cowpea and soybean resulted in higher yield. Defatted starches also had higher amylose contents with low protein, fat and ash contents than full fat starches. In addition, defatted starches from cowpea and soybean had higher water absorption capacity, swelling power, blue value index and low bulk density, higher peak viscosity, trough, final viscosity, setback values than full fat cowpea and soybean starches while cassava starch had higher peak time and pasting temperature than the legume starches. The full fat starches from soybean and cowpea had high breakdown and low setback values than the defatted samples and control. The extensibility values of defatted starches were significantly (p ≤ 0.05) higher than full fat starches but lower than control. There was no significant (p ≥ 0.05) difference in texture and appearance of stiff porridges prepared from cowpea, soybean and cassava starches. Similarly, there was no significant (p ≥ 0.05) difference in mouldability, stickiness and overall acceptability between defatted starches and control but significantly different (p ≤ 0.05) with the full fat starches. It is therefore concluded that consumption of such stiff porridges could be beneficial to individuals requiring decreased and/or slow starch digestibility such as diabetic patients and long distance athletes since legume starches are known to have low starch digestibility.     

Thermal treatments affect the polyphenol profile and increase antioxidant capacity in five varieties of edible bean milks

We investigated the influence of two thermal treatments, steaming and boiling, on polyphenol profile and antioxidant capacity in milks from five edible bean varieties, including green mung bean milk, yellow and black soya bean milk, rice bean milk and white cow gram milk. The two thermal treatments had different influences on polyphenol profile and antioxidant capacity with steaming better than boiling in increasing total phenolic content (TPC) and antioxidant capacity in edible bean milks. In particular, steaming substantially increased soya bean isoflavone glucosides in the two soya bean milks. Bioconversion between polyphenols, the release of bound polyphenols and the induction of Maillard reaction products could contribute to the increase in TPC and antioxidant capacity in some edible bean milks. Therefore, it is recommended to steam edible bean milk for consumption, and edible bean milk containing antioxidant polyphenols can be developed into functional drinks with potential health benefits.     

Comparative Studies on Physico-Chemical Properties of Starches from Jackfruit Seed and Mung Bean

The physico-chemical properties of starch from jackfruit seed and mung bean were investigated. Jackfruit seed starch had much higher resistant starch content (26.99%) than that of mung bean starch (4.04%). Furthermore, jackfruit seed starch had a higher gelatinization temperature (T_o) that required more gelatinization energy (ΔH) compared to mung bean starch. However, mung bean starch had higher amylose content and its granules were much larger than that of jackfruit seed starch. Mung bean starch had the highest peak viscosity, breakdown, and setback whereas jackfruit seed starch had the highest pasting temperature. Amylopectin chain length of mung bean starch contained higher proportion of short chains (degrees of polymerization 6–12) but lower proportion of very long chains (degrees of polymerization > 37 ) comparing with jackfruit seed starch. The X-ray diffraction patterns showed both starches to be Type-A crystallinity. In addition, both starch gels showed higher the storage modulus (G′) than the loss modulus (G?) designating as rubber like material. However, mung bean starch gel exhibited higher G’ and less tan δ than that of jackfruit seed starch indicating much stronger of gel structure.     

不同种类淀粉与黑米粉复配体系的理化性质和分子结构特性研究

为了改善黑米粉的凝胶特性,分别将绿豆淀粉、马铃薯淀粉和玉米淀粉与黑米粉进行复配。对复配体系的糊化特性及凝胶质构特性进行测定,并结合低场核磁共振分析仪、傅里叶变换红外光谱和X射线衍射仪进一步分析复配体系的分子结构特性。结果表明：随着淀粉浓度的增加,淀粉-黑米粉复配体系的峰值黏度均显著增加,糊化时间和温度降低。绿豆淀粉和马铃薯淀粉显著增强了复配体系的持水力和膨润力,马铃薯淀粉和玉米淀粉显著降低了复配体系的溶解度。三种淀粉均可以促进复配体系凝胶网络结构的形成,改善凝胶的质构特性,包括凝胶的硬度、弹性、咀嚼性和回复性。此外,三种淀粉增强了复配体系淀粉链间的氢键相互作用,降低了凝胶的持水性,增强了体系的分子短程结构有序性和相对结晶度。上述研究表明,三种淀粉都可以改善黑米凝胶的品质,且绿豆淀粉的改善效果更佳。     

蔗糖对不同品种赤小豆淀粉性能的影响

以三种不同赤小豆淀粉为原料,通过分析添加蔗糖前后淀粉的糊化性能、热力学性能、消化性能等特性,探究蔗糖对淀粉性能的影响。结果表明：直链淀粉含量较高的珍珠红赤小豆淀粉,具有较大的粒径、较高的峰值黏度和回生值,但其糊化温度和最终黏度较低;当添加10%的蔗糖后,三种淀粉的平均粒径、峰值黏度、凝沉性和快速消化淀粉（Rapidly digestible starch,RDS）显著降低（P<0.05）,而三种淀粉的糊化温度、热焓值、回生值和衰减值却显著增加（P<0.05）;慢速消化淀粉（Slowly digestible starch,SDS）含量除珍珠红赤小豆淀粉外均显著增加（P<0.05）,淀粉凝胶性以及抗性淀粉（Resistant starch,RS）虽有下降,但不显著。蔗糖的添加促进了赤小豆淀粉的回生;抑制了淀粉的糊化、降低了抗老化性和消化性。     

Effect of high hydrostatic pressure on physicochemical, thermal and morphological properties of mung bean (Vigna radiata L.) starch

Mung bean starch-water suspension was subjected to high pressure treatment at 120, 240, 360, 480 and 600 MPa for 30 min, and changes in the structure, morphology and some physicochemical properties were investigated. Light transmittance, swelling power and solubility decreased after the high hydrostatic pressure treatment. A significant increase in the peak viscosity, trough viscosity, final viscosity, pasting temperature and setback, and decrease in breakdown viscosity with increase in pressure treatment was observed. The differential scanning calorimeter (DSC) analysis showed a decrease in gelatinization temperatures and gelatinization enthalpy upon high pressure treatments. The X-ray analysis showed that high hydrostatic pressure (HHP) treatment converted starch that displayed the C-type X-ray pattern to the B-type-like pattern. The HHP treatments altered the shape of starch granules and changed their surface appearance according to SEM analysis. HHP treatment (600 MPa, 30 min) caused a completely gelatinize of mung bean starch.