Preparation of lactic acid bacteria compound starter cultures based on pasting properties and its improvement of glutinous rice flour and dough

The effects of 5 lactic acid bacteria(LAB)fermentation on the pasting properties of glutinous rice flour were compared,and suitable fermentation strains were selected based on the changes of viscosity,setback value,and breakdown value to prepare LAB compound starter cultures.The results revealed that Latilactobacillus sakei HSD004 and Lacticaseibacillus rhamnosus HSD005 had apparent advantages in increasing the viscosity and reducing the setback and breakdown values of glutinous rice flour.In particular,the compound starter created using the two abovementioned LAB in the ratio of 3:1 had better performance than that using a single LAB in improving the pasting properties and increasing the water and oil absorption capacity of glutinous rice flour.Moreover,the gelatinization enthalpy of the fermented samples increased significantly.For frozen glutinous rice dough stored for 28 days,the viscoelasticity of frozen dough prepared by compound starter was better than that of control dough,and the freezable water content was lower than that of control dough.These results indicate that compound LAB fermentation is a promising technology in the glutinous rice-based food processing industry,which has significance for its application.

Effect of Glutinous Rice Flour on Mechanical Properties and Microstructure of Cement-based Materials

The mechanism of glutinous rice flour,a kind of natural admixture,on the hydration process,setting time,and microstructure of the Portland cement was investigated.The experimental results show that the glutinous rice flour has an obvious setting retarding effect on cement pastes.The optimal dosage of the glutinous rice flour is 3wt%.In this case,the initial and final setting time of the paste are delayed by 140 and185 min,respectively.The flexural and compressive strengths of the hardened paste are increased by 0.35%and 0.07%after 56 d of curing.The glutinous rice flour hinders the mineral dissolution process and decreases the concentration of calcium ion at the initial stage of hydration due to the complexation effect,thereby hindering the nucleation and growth of CH and C-S-H phases and prolonging the hydration process.However,C-S-H phases combine with the glutinous rice flour to contribute the bonding effect together,which compacts the microstructure of hardened cement pastes at the later hydration stage of cement pastes.Thus,in-depth investigation on the utilization of glutinous rice flour as the admixture for the Portland cement is expected to be meaningful for the control of hydration exothermic rate and setting time.

Effects of Storage Temperature on Pasting Properties of Brown Rice

[Objective] The aim of this study was to explore the effects of storage temperature on pasting properties of brown rice.[Method] Rapid viscosity analyzer was used to determine the viscosity of brown rice under different storage temperatures（30,25,20 and 15 ℃）.[Result] The peak viscosity value increased with storage time prolonging.The higher the storage temperature was,the more rapidly the increasing of peak viscosity value;different storage temperatures and storage time showed significant effects on peak viscosity value of brown rice;the difference on peak viscosity value of brown rice under different storage temperatures was significant.The hot viscosity value of brown rice stored under 30 and 25 ℃ gradually increased with the storage time prolonging;and storage time and storage temperature showed significant effects on hot viscosity value;there was extremely significant difference on hot viscosity value of brown rice under 30,25 and 20,15 ℃.The breakdown value showed a first increasing and then decreasing trend with the storage time prolonging;storage temperature and storage time had extremely significant effect on the breakdown value of brown rice;the breakdown value of brown rice among each storage temperature was extremely significant.The final viscosity of brown rice increased with storage time prolonging.The higher the temperature was,the higher the increasing rate of final viscosity;storage time and temperature showed extremely significant effect on the final viscosity of brown rice;the difference on final viscosity among different storage temperature treatments was extremely significant.The changes on setback value of brown rice under different storage temperature treatments were different with the storage time prolonging;and the storage temperature showed extremely significant effect on the setback value of brown rice.[Conclusion] The study had provided theoretical basis for the storage of brown rice.

Pasting properties by near-infrared re flectance analysis of whole grain paddy rice samples

A rapid predictive method based on near-infrared re flectance spectroscopy(NIRS)of paddy rice was developed to measure the pasting properties of rice.The paddy rice samples were scanned by a near-infrared re flectance spectrometer in the wavelength region of 1400–2400 nm and preprocessed by mathematical pretreatments prior to pasting properties analysis using a rapid visco-analyzer(RVA).The results indicated that the developed models of setback(SB),peak viscosity(PV),breakdown(BD)and consistency(CS)provided good prediction results with relatively high correlation coe±cients(0.81–0.96).In addition,the validity of the calibration models was statistically tested.Standard error of prediction(SEPT) and bias were small enough without any significance at 95% confidence interval.Nonetheless,this study proved that the use of NIRS for predicting pasting properties was feasible in paddy rice and could be applied in commercial trade and research.

Synthesis and paste properties of octenyl succinic anhydride modified early Indica rice starch

Octenyl succinic anhydride （OSA） modified early Indica rice starch was prepared in aqueous slurry systems using response surface methodology. The paste properties of the OSA starch were also investigated. Results indicated that the suitable parameters for the preparation of OSA starch from early Indica rice starch were as follows： reaction period 4 h, reaction temperature 33.4℃, pH of reaction system 8.4, concentration of starch slurry 36.8% （in proportion to water, w/w）, amount of OSA 3% （in proportion to starch, w/w）. The degree of substitution was 0.0188 and the reaction efficiency was 81.0%. The results of paste properties showed that with increased OSA modification, the starch derivatives had higher paste clarity, decreased retrogradation and better freeze-thaw stability.

Effects of Polishing on Proximate Composition,Physico-Chemical Characteristics,Mineral Composition and Antioxidant Properties of Pigmented Rice

The effects of polishing on proximate compositions,physico-chemical characteristics,mineral compositions and antioxidant properties of the rice flours obtained from three different pigmented rice varieties(Chak-hao Angangba,Chak-hao Amubi and Chak-hao Poireiton) were investigated.The rice varieties were significantly(P < 0.05) different in the contents of the test characteristics.Lipids,ash,minerals,phytochemicals(phenolic acids and flavonoids) and 2,2-diphenyl-1-picrylhydrazyl(DPPH) activity of rice flours were decreased after polishing(9% degree of milling),while amylose content and lightness were increased.X-ray diffraction pattern of rice flours exhibited A-type crystalline pattern with reflections at 15.1o,17.1o,18.2o and 23.0o.Pasting properties and transition temperatures were decreased after polishing treatment.Polishing resulted in changes in the crystallinity,enthalpy and morphology of rice flours.

Effect of Soaking Temperature on Physical and Functional Properties of Parboiled Rice Cultivars Grown in Temperate Region of India

The physical and functional properties of seven parboiled rice cultivars (Jehlum, K-332, Koshar, Pusa-3, SKAU-345, SKAU-382 and SR-1) were investigated at different soaking temperatures of 60℃, 70℃ and 80℃ and it was compared with the brown raw rice of the respective cultivars. Parboiling was observed to decrease L* value and increase a* and b* values. The hardness of rice was significantly increased after parboiling and varied among the cultivars with the highest in Jehlum. Parboiling resulted in the decrease of pasting parameters with the increase in soaking temperature from 60℃ to 80℃. The pasting characteristics of parboiled rice sample showed the typical behaviour having high initial viscosity, but lower peak viscosity in comparison to raw rice. The water absorption index and water solubility indices were subsequently increased with the increase in soaking temperature.

中国古代糯稻的功用

糯稻在今天是小宗作物,在古代却有着重要而广泛的用途。在自然属性层面,熟糯米的优异理化性质使其成为理想的酿料、食物、粘合剂及药物,糯禾则因抗逆性强而成为一种先锋作物;在社会属性层面,糯米的神圣文化内涵又使其成为必需的祭品、礼品和标志物。梳理古代糯稻的功用对理解古代糯稻的栽培和加工颇有裨益。

米粉质构特性与稻米理化性状的关系

【目的】探明决定米粉稻品种米粉质构特性的关键稻米理化性状指标,为优质米粉专用稻品种的选育提供理论依据。【方法】以5个米粉稻品种(广陆矮4号、中嘉早17、湘早籼24号、中早39、株两优729)为材料,于2020-2022年早季和晚季在湖南浏阳进行大田试验。【结果】米粉稻在不同年份和季节种植,加工出的米粉质构特性差异均达显著水平(P<0.01)。米粉硬度、弹性、咀嚼性、内聚性和回复性变化范围分别为1651~4083 g、0.860~0.922、1295~2685 g、0.760~0.858、0.532~0.633。相关分析表明,米粉硬度和咀嚼性与稻米理化性状相关不显著。米粉弹性与总淀粉和直链淀粉含量呈显著正相关(P<0.01),与消减值呈显著负相关(P<0.05)。【结论】米粉稻存在适宜种植的气候条件。总淀粉、直链淀粉含量和消减值是决定米粉稻品种米粉质构特性的关键指标。总淀粉和直链淀粉含量高,消减值低的米粉稻品种加工出的米粉弹性好。

木糖醇对糯米粉理化性质及汤圆品质的影响

将不同添加量(0%~25%)的木糖醇添加至糯米粉中构建木糖醇-糯米粉共混体系,探讨木糖醇对糯米粉的糊化特性、热力学特性、凝胶质构、流变学特性和消化特性等性质以及对其制成的汤圆品质的影响。结果表明:木糖醇的添加使共混体系的糊化温度、峰值黏度和终值黏度有所提高,体系的短程有序程度降低,体系表现为假塑性流体,具有剪切稀化行为。与对照组相比,木糖醇添加量为10%时,共混体系的回生值和凝胶硬度最小,分别为405 cP和14.952 g,体系抗性淀粉含量为29.88%,表现出较好的抗回生性。但高浓度木糖醇(15%~25%)促进体系发生短期回生,增加其回生值和弹性。另外,木糖醇的添加显著降低了汤圆的冻藏水分损失率和汤汁透过率,其中添加10%的木糖醇制成的汤圆具有更高的硬度、弹性、回复性以及咀嚼性,食用品质最好。本研究为木糖醇改善糯米粉品质以及糯米粉产品开发提供参考。

抛光色选工艺过程对香稻米2-AP含量和糊化特性的影响

抛光色选工序是生产食用大米的重要步骤,会影响稻米品质和香气2-乙酰基-1-吡咯啉(2-AP)含量。以香稻品种19香和软华优金丝为材料,研究了工业生产中抛光色选工艺过程对香米2-AP含量和糊化特性的影响。结果表明,在稻米抛光阶段增加抛光色选程序会导致19香和软华优金丝2-AP含量分别损失51.66%和38.10%,蛋白质含量分别降低7.31%和1.49%,水分含量、淀粉峰值黏度、最低黏度、最终黏度和消减值都有上升,而回冷值降低。

脱乙酰魔芋葡甘露聚糖对挤压熟化米粉品质的影响

为探究脱乙酰魔芋葡甘露聚糖(deacetylated konjac glucomannan,DKGM)改善挤压熟化米粉品质的机制,该研究考察不同脱乙酰度DKGM(0%、27.62%、47.62%、59.81%、76.19%)对米粉糊化及流变性质、蒸煮品质、质构特性的影响,并通过X射线衍射、傅里叶变换红外光谱、扫描电镜探究其作用机理。结果表明,DKGM能显著缩短米粉的最佳蒸煮时间,降低断条率,增加透光率。其中适度脱乙酰的DKGM(47.62%)使米粉的蒸煮损失率由9.59%降至5.00%,硬度由1544.79 g降至1158.00 g。而高脱乙酰度DKGM(76.19%)组米粉蒸煮损失率仅比纯大米粉组降低了1.07%。X射线衍射分析表明DKGM能够抑制淀粉的重结晶,延缓老化。扫描电镜观察发现,添加DKGM使米粉具有更均匀的网络结构,但当DKGM脱乙酰度超过59.81%时,米粉结构变得松散。因此,添加适度脱乙酰的DKGM(47.62%)能够显著改善米粉蒸煮品质及质构特性。该研究可为DKGM在米制品中的应用提供理论依据,拓宽了魔芋葡甘露聚糖在食品加工中的应用。

α-环糊精对糯米淀粉凝胶特性的影响

为探究α-环糊精对糯米淀粉凝胶特性的影响。以糯米淀粉为原料,将α-环糊精(质量分数0%~10%)与糯米淀粉共混,测定淀粉凝胶的微观结构、流变特性、糊化特性、质构特性和短程有序性。结果表明:随着α-环糊精的添加,淀粉凝胶网络结构中的孔洞分布变得均匀。此外,α-环糊精的存在降低了淀粉凝胶的G′、硬度、回生值,但显著提高了凝胶的弹性和透明度。傅里叶红外结果表明,糯米淀粉的短程有序性随着α-环糊精添加量的增加而逐渐下降,α-环糊精与糯米淀粉之间并未发生化学反应。

优质籼稻变温储藏糊化特性变化规律与动力学模型

为了探究籼稻在变温储藏过程中糊化特性变化规律,为低温储粮工艺合理调控提供理论依据,研究了初始水质量分数为14.0%、14.5%、15.0%的籼稻在低温、准低温、室温储藏条件下糊化特性及食味品质变化规律,并建立了糊化参数变化的动力学模型。结果表明:随着储藏时间的延长,室温下籼稻峰值黏度、最低黏度、最终黏度和回生值的增长幅度较低温、准低温下显著,平均增幅分别为1866、1215、1572、523 cP,偏高水分样品糊化指标变化幅度相对剧烈,峰值黏度和最低黏度与食味品质的相关性更强(P<0.01),说明低温或准低温下储藏有利于延缓籼稻食味品质变化。采用零级和一级动力学模型、高斯模型和傅里叶级数对各项糊化指标进行拟合,分析比较可知,高斯模型对籼稻在不同储藏条件下峰值黏度和最低黏度变化的拟合结果最优,模型决定系数(R^(2))分别在0.668~0.942和0.687~0.906范围内,傅里叶级数对最终黏度和回生值变化的拟合结果较好,R^(2)分别在0.661~0.861和0.701~0.868范围内。

青稞粉对鲜榨米粉团糊化和流变学特性的影响及其蒸煮品质分析

为研究青稞粉对鲜榨米面团糊化和流变特性的影响,向鲜榨米粉中添加0%、10%、20%、30%、40%质量分数的青稞粉制成粉团,测定其糊化特性、流变特性和热稳特性,分析其品质变化。结果表明:添加青稞粉可以提高糊化温度,减缓加热过程中弹性模量和黏性模量剧烈波动。当青稞粉质量分数为30%时,其糊化特性最好,糊化温度达90.15℃;流变学曲线变化趋势最缓;活化能最小,即108.7 kJ/mol;热稳性模型方程为Y=104.4 exp(-108.7/8.3143 T)。

红豆糯米饼的工艺研究与品质控制

在保证食品安全的前提下,对红豆糯米饼配方进行优化,并探讨低温储藏对产品的影响。采用单因素试验对糯米面皮所需的牛奶含量、糖含量,馅料红豆沙的添加量,以及烘焙的温度和时间进行研究。应用正交试验对牛奶添加量、烘焙温度和烘焙时间进行优化。结果表明,最佳工艺参数为60 g糯米粉,白砂糖6 g、牛奶55 g、红豆沙20 g,190℃烘烤16 min。样品放置一周后,硬度、内聚性和咀嚼性测定数值均表现为上升。

Thermal and textural properties of extruded rice affect its cooking performances and the texture of the steamed extruded rice

Extruded rice has increasingly gained popularity in the market due to its convenience and acceptable texture.The objective of this study was to understand how the physicochemical,thermal,and textural properties of the extruded rice affected its cooking properties and texture of the cooked one.It was found that air trapped in the grains during extrusion reduced the transparency of extruded rice.More air trapped in the grains reduced the true density of the extruded rice,which in turn decreased the hardness of extruded rice.A looser internal structure of extruded rice grain,as indicated by the lower true density,resulted in a faster hydration and shorter optimum cooking time.Extruded rices showed two thermal-transition peaks,with peak 1 from 93.3℃ to 112.8℃ and peak 2 from 107.5℃ to 132.5℃.The increased hardness of extruded rice led to increases in its thermaltransition temperatures,longer optimum steaming time,and decreases in its water absorption and cooking loss,which resulted in an increase in the hardness and a reduction in the adhesiveness of the steamed one.This study provides insights into the key factors determining the eating quality of extruded rice,which is beneficial for food scientists in developing premium extruded rice.

转谷氨酰胺酶对米粉、米面团和米面包的改良

为改善米面包品质,揭示转谷氨酰胺酶(TG酶)对米粉、米面团和米面包品质的影响及各指标之间的联系,对添加不同质量分数TG酶的米粉的粉质特性和糊化特性,米面团的水分分布、流变特性和发酵特性,以及米面包的比容、气孔和质构等指标进行了测定。结果表明,0.60%TG酶能够改善米粉的粉质特性和糊化特性,将米粉的稳定时间提高至8.00±0.77 min,峰值粘度(PV)、谷值粘度(VV)和最终粘度(FV)分别提升为5801.00±30.41、3805.67±76.14和5836.33±106.17 cP,降低米粉的衰减值(BD)和回生值(SB)等糊化参数至1990.00±128.11和1991.67±34.08 cP;同时TG酶增加米面团中水分结合的紧密程度,改善米面团的流变特性和发酵特性,将S_(21)升至9.24%±13.07%和将T_(21)和T_(22)分别降至1.40±1.80和30.45±2.28 ms,Hm提高至8.60±0.11 mm;孔隙率提高至50.51%±0.90%,降低米面包的硬度、胶粘性和咀嚼性,提高米面包的弹性,改良米面包的质构。相关性分析表明,T_(23)和形成时间呈负相关,Hm与C3、C3~C2和VV呈正相关,与BD和SB呈负相关,咀嚼性和C1呈正相关,比容与FV和PV呈正相关。实验结果说明,TG酶可以改善米粉、米面团和米面包的品质,且改良的各指标间存在不同程度的相关性。

富硒锌重组米挤压工艺优化及糊化特性研究

以糙米粉为原料,通过加入L-硒-甲基硒代半胱氨酸和L-乳酸锌2种营养强化剂制备全谷物挤压重组米。在单因素试验的基础上通过响应面法优化重组米的挤压工艺,并对重组米的糊化特性进行分析。结果表明:最优工艺为挤压温度92℃、螺杆转速180 r/min、物料水分含量28%、原料粒度0.20 mm,此条件下制备的重组米平均综合得分为80.1842±0.5312;重组米糊化特性的各项指标均低于大米、留胚米和糙米;重组米中硒含量为(182.2208±6.6253)μg/kg,锌含量为(15.4589±2.2260)mg/kg。

预处理-低温挤压对留胚米粉理化性质的影响

以留胚米为原料,焙炒预糊化粉碎后,在挤压机螺杆转速100 r/min,水分含量30%,挤压温度50~90℃的条件下对留胚米粉进行挤压。研究在预糊化-低温挤压过程中不同的挤压温度对留胚米粉理化性质的影响。结果表明:随着挤压温度的升高,留胚米粉的糊化度逐步提高;淀粉、脂肪、蛋白质、γ-氨基丁酸(GABA)含量均有所下降,而当温度超过70℃后,可溶性膳食纤维含量显著(P<0.05)升高;留胚米粉的吸水性指数显著下降(P<0.05),水溶性指数、膨胀势有所上升;总色差?E增大;粒径显著增大(P<0.05);差示扫描量热仪分析发现留胚米粉的起始温度(T_(0))、峰值温度(T_(P))和终止温度(T_(C))逐渐升高,吸热焓由1.14 J/g下降至0.82 J/g,糊化程度逐步增加;傅里叶红外光谱分析表明,在所有挤压温度下留胚米粉的淀粉结构中并未产生新的基团或化学键。上述结果显示,预糊化-低温挤压对留胚米粉的理化特征具有显著影响,适宜的挤压温度减少了营养成分的损失。