Physicochemical properties,resistant starch content and enzymatic digestibility of unripe banana,edible canna,taro flours and their rice noodle products

Unripe banana, edible canna and taro flours, which have been reported to contain significant amounts of fibre, were investigated for their physicochemical properties, resistant starch (RS) content and in vitro starch digestibility, and compared with commercial high‐fibre‐modified starches from corn and tapioca. Differential scanning calorimetry showed a single endothermic peak located around 70–83 °C for the samples except the modified starches, which exhibited no transition enthalpy. The samples showed different pasting behaviours in the Rapid Visco‐Analyser (RVA) ranging from full to restricted swelling. The RS content varied from 1–26 g per 100 g dry sample, and the estimated glycaemic indices (GIs) of the samples were from 67% to 99%. Generally, samples with high RS were low in GI values. The starches produced acceptable rice noodles but with reduced rate of starch digestion and GI. The effects of the unripe banana, edible canna and taro flours on starch digestibility were either comparable or better than the commercial modified starches. These flours can substitute commercial modified starches to lower GIs of noodles and identical foods.     

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。     

谷氨酰胺转氨酶对挤压糙米粉面团蛋白特性和面条品质的影响

将挤压糙米粉(EBR)与小麦粉以1∶1(m/m)的比例混合制成面条,研究了谷氨酰胺转氨酶(TG)添加量(0.5%、1.0%和1.5%)对面条性质的影响。结果表明,TG添加后,面条中游离巯基含量减少,SDS-PAGE条带显示面条中形成了大分子质量的聚集体。随着TG的添加,面条最佳蒸煮时间增加,干物质损失率降低,吸水率升高。添加量为1.0%时,面条最佳蒸煮时间和吸水率达到最大值,蒸煮损失率达到最小值。TG添加量为0.5%时,面条的硬度、耐咀性、回复性和剪切力最大。扫描电镜结果显示,TG的添加明显增强了面条内部结构的连接与聚合,面条内部变得更加紧实,连续性增强。TG添加量为0.5%~1.0%时,挤压糙米粉面条质构品质和蒸煮品质较好。     

A Study of Some Physicochemical Properties of High‐Crystalline Tapioca Starch

Tapioca starch was partially hydrolyzed in hydrochloric acid solution at room temperature for various lengths of time to obtain high‐crystalline starches. RVA viscoamylograms of acid‐modified starches demonstrated a very low viscosity as compared to that of native tapioca starch. The relative crystallinity of native and acid‐modified tapioca starches were measured by X‐ray diffraction ranging from 39.53% to 57.75%. The native and acid‐modified tapioca starches were compressed into tablets using various compression forces. The % relative crystallinity of starch increased with the increase in hydrolysis time and the crushing strength of the tablet was also increased in line with the crystallinity while the amylose content decreased when the crystallinity increased. These results suggested that the erosion of amylose might cause the rearrangement of starch structure into a new more tightly packed form, which provided the higher crushing strength for the tablets.     

Production of high-fructose rice syrup and high-protein rice flour from broken rice

The objective of this study was to develop a process for the production of both high-fructose rice syrup and high-protein rice flour from broken rice. The rice flour was obtained from broken rice by using either a dry or wet milling method. The glucose produced from the slurry of various raw materials by treating with α-amylase and glucoamylase was compared. Results indicated that cassava and corn starch were better raw materials than rice flour. However, the filtered residue of liquefied rice slurry could be recovered as high-protein rice flour. The particle size of rice flour had a small effect on the glucose yield. The orthogonal-array table (L₂₇) method of experimental design was employed to determine optimum conditions for liquefaction. The glucose yield based on starch was 90.8±3.6% under the following optimum conditions α-amylase, 0.12%; rice flour, 20%; temperature, 96°C; time, 90 min. The filtrate from liquefied rice slurry was saccharified at 60°C with three different concentrations of glucoamylase. The higher the enzyme concentration, the shorter the time required to reach the maximum yield. After saccharification, the glucose solution was decolourised, desalted and concentrated to 40% d.s. and then isomerised to fructose at 60°C under continuous operation by using immobilised glucose isomerase packed in a column. The isomerised syrup was then purified and concentrated to 71% d.s. The final high-fructose rice syrup contained 50% glucose, 42% fructose and 3% maltose. After liquefaction, the rice slurry was centrifuged and the precipitate was dried by either spray or drum drying. The composition of these two high-protein rice flours was almost the same and the protein content was about three times as high as the raw material. There were significant differences in surface structure of rice flour and high-protein rice flours, as observed by the scanning electron microscope.     

Dependence of Thermodynamic Characteristics of Amylose‐Lipid Complex Dissociation on a Variety of Wheat

Native wheat starch contains amylose‐lipid complexes (AMLs) that are formed both upon biosynthesis of native starch and upon heating of starch slurries at gelatinization temperature and above. These complexes have a detrimental impact on physicochemical properties of starch, because they reduce water binding by starch granules and retard their swelling. An objective of the presented work was to analyze the chemical composition of wheat starch and characterize the thermodynamics of gelatinization of different wheat starches and to evaluate the stability of AMLs derived from these starches with the aid of differential scanning calorimetry (DSC). Grains of eight wheat varieties were used throughout the studies. The gelatinization behavior of the eight wheat varieties examined was similar. The lowest temperature of the onset of gelatinization (T_k = 57.07°C) was found for the Jawa variety, and the highest (T_k = 60.58°C) for the Torka variety. Enthalpy of gelatinization (ΔH_k) of the examined wheat starch preparations ranged from 9.14 J/g (Sakwa) to 11.95 J/g (Elena). Temperature and enthalpy of AMLs dissociation depended on wheat starch variety. During the first heating the temperature of the minimum of the endotherm (T_d) ranged from 98.41°C to 100.5°C. During the second heating, the minimum was at slightly higher temperatures, varying from 102.02°C to 104.08°C. Enthalpies of AML dissociation (ΔH_d) varied from 1.45 J/g to 2.14 J/g during the first heating. During the second heating the enthalpy values were slightly lower (1.26 J/g to 1.68 J/g). Enthalpies of AML reassociation ranged from 1.29 J/g to 1.72 J/g during the first cooling, and from 1.17 J/g to 1.63 J/g during the second cooling. A correlation was found between the amount of lipids and AML content.     

A Calorimetric Study of the Interaction between Waxy Maize Starch and Lipid

There is considerable debate on the definition and measurement of the amount of amylose in starch and whether hydrophobic ligands can form a complex with amylopectin. One method for amylose determination is through the measurement of amylose‐lipid complexation using differential scanning calorimetry (DSC), with the assumption that amylopectin cannot form such a complex. As the sensitivity and methodologies used for DSC improves, the validity of this assumption needs to be tested once again. For the experimental work, α‐L ‐lysophosphatidylcholine (LPC, 10% of starch dry weight) was used as the complexing agent and waxy maize starch. Optimisation of the DSC included changing the heating rate from 10ºC/min to 40ºC/min, which resulted in a higher sensitivity enabling the recording of an endotherm associated with the dissociation of a starch‐LPC complex. The observation of the endothermic formation of such complex could only be achieved when a microcalorimeter, which analyses a much larger sample than a standard calorimeter (190 mg of dry starch compared to 13 mg) was used. There are two possible interpretations for these observations: Either waxy maize starch contains traces of amylose (~ 0.5‐0.7%) and the DSC is sufficiently sensitive to detect these amounts or the α‐1,6 glucan long branches of waxy maize starch bind linear aliphatic compounds.     

Retrogradation of partially gelatinised potato starch prepared by ball milling

This study was performed to evaluate the effect of partial gelatinisation on the retrogradation of modified potato starch. The partially gelatinised starches with gelatinisation degree at mean levels of 22.47%, 49.18%, 76.80% and 86.19% were prepared by ball milling (0.5, 1.5, 3 and 10 h). The thermal properties and crystal structure of retrograded starch were examined during 21 days of refrigerated storage at 4 °C. Retrograded starch with high initial gelatinisation degree (86.19%) showed higher retrogradation enthalpy of 6.12 ± 0.18 J g^?1 and lower onset temperature of 45.41 ± 0.24 °C than sample with low gelatinisation degree (22.47%) where the results were 1.32 ± 0.18 J g^?1 and 54.05 ± 0.03 °C, respectively. During storage, two peaks in the X‐ray diffractograms for starch with high gelatinisation degree appeared and increased rapidly, while the peaks for starch with low gelatinisation degree increased slowly. These results suggest that a certain amount of remainder crystals presented in partially gelatinised starch impeded the retrogradation.     

挤压温度和物料水分对糙米粉中损伤淀粉及面条品质影响

在不同挤压温度和物料水分条件下将糙米粉挤压膨化,并将挤压膨化糙米粉与小麦粉的混合粉(1∶1,w/w)制成糙米面条,系统研究了挤压温度和物料水分对挤压糙米粉中损伤淀粉含量和糙米面条品质的影响,同时分析了损伤淀粉含量与面条品质的相关性。结果显示:随着物料水分的增加,糙米粉中损伤淀粉的含量显著减少,物料水分25%时损伤淀粉含量UCDc值达到最低14.9;随着挤压温度升高,糙米粉损伤淀粉含量先减少后增加,温度120℃时损伤淀粉含量UCDc值达到最低14.9;相关性分析结果显示,随着损伤淀粉含量的增加,面条蒸煮损失明显增大,坚实度、硬度和耐咀性降低,面条整体品质下降。挤压温度120℃、物料水分25%、损伤淀粉含量UCDc值为14.9,糙米面条品质相对较好。      

Effects of potato starch on the characteristics,microstructures and quality attributes of indica rice flour and instant rice noodles

The effects of partial replacement (0%–20%, w/w) of rice flour by potato starch (PS) on the physicochemical properties, microstructures, texture and in vitro digestibility of indica rice flour (IRF) and instant rice noodles (IRN) were systematically investigated. Accordingly, the addition of PS significantly increased the peak viscosity (2876.00–3221.00 mPa·s) and tan δ values (0.14–0.22) but lowered the setback values (2169.00–1036.50 mPa) of the pastes. Rice noodles with 5%–15% PS (PS and IRF at the mixing ratios of 5:95, 10:90, 15:85 and 20:80, respectively) addition exhibited modulated appearance and textural properties. The mutually exclusive phosphate groups of PS facilitated the expansion of starch granules, contributing to the formation of more compact microstructure and higher-ordered crystalline structures (confirmed by scanning electron microscope and X-ray diffraction), endowing rice noodles with better cooking and digestive attributes, and visibly increased slowly digestible starches content (26.09%–31.34%). The quality attributes of rice noodles could be accurately predicted by the physicochemical properties of rice flour referring to Pearson’s correlation analysis. The study demonstrates that the blending of PS is both an effective and economical pathway in improving the nutritional and textural properties of IRN.     

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。     

Functional and thermorheological properties of rice flour gels for gluten-free pasta applications

Based on the European Commission directives on circular economy, this work explores the functional and thermorheological properties of rice flour from broken kernels, a by-product from the rice industry, in order to evaluate its possible use in food applications, back into the value chain. Chemical and hydration properties of two rice varieties (Guiana – Indica spp, Ariete – Japonica spp) were accessed, as well as the impact of the rice variety on the texture and viscoelasticity of rice flour gels (6–26%). Both rice varieties presented statistically different physicochemical properties (protein, lipid and amylose contents), and hydration properties that support the distinct texture and rheology behaviour of gels obtained. Rheology results suggested the formation of a gel-network structure with high frequency dependence, especially at lower rice concentrations. Texture results suggest that both rice varieties could be suited for development of gluten-free products that require pre-gelatinised starch, such as pasta. The effect of gelatinised rice flour (10–25%) and gelatinised flour/rice flour ratio (40:60, 50:50, 60:40) on the physical properties and cooking quality of pasta were assessed. Better overall cooking quality and texture properties were obtained for the formulation with 20% gelatinised rice flour and 50:50 rice gel:rice flour ratio.     

Effect of pre-gelatinised high-amylose maize starch combined with Ca2+ -induced setting of alginate on the physicochemical and sensory properties of rice flour noodles

This study explored the effect of pre-gelatinised high-amylose maize starch combined with Ca²⁺ -induced setting of alginate on the physicochemical and sensory properties of rice flour noodles. Rice flour noodles were prepared by partially substituting rice flour with pre-gelatinised high-amylose maize starch in ratios of 5, 10 and 15% (wt/wt), combined with sodium alginate at 1% (wt/wt). The noodles were then immersed in a calcium chloride solution to set the alginate. Results indicated that the hydrocolloids significantly (P < 0.05) increased noodle tensile strength, hardness, water absorption and optimum cooking time while cooking loss was significantly (P < 0.05) reduced. SEM micrographs showed a denser, compact noodle structure with an increase in the matrix's continuity as a result of hydrocolloids addition. Formulated noodles also scored above average (5.91) sensory acceptability on the 7 points hedonic scale. Overall, results proved promising for the preparation of rice flour noodles with enhanced properties.     

糯米粉理化特性及与麻球品质的相关性

为提高麻球产品质量,指导麻球工业化生产合理选择糯米粉原料。以16种糯米粉原料为研究对象,测定其理化特性(直链淀粉含量、粗蛋白含量、粗脂肪含量、破损淀粉含量、糊化特性)及麻球品质特性,同时通过分析糯米粉各品质指标与麻球品质的相关性,探讨糯米粉原料特性对麻球品质的影响。结果表明,糯米粉粗蛋白含量与麻球比容、色泽、硬度指标均呈显著负相关,与麻球形状和总分均呈极显著负相关;衰减值与麻球比容得分呈显著正相关,而峰值时间、糊化温度与麻球比容呈极显著负相关,最低粘度、最终粘度、回生值与麻球的外观均呈显著负相关。因此,在选择麻球生产原料糯米粉时,应综合考虑其粗蛋白含量和糊化特性。依据本研究所用的糯米粉,得出粗蛋白含量在6.80%以下,衰减值高于1 282 c P,最低粘度低于1 526 c P,最终粘度低于1 950c P,回生值低于424 c P,峰值时间低于3.9 min,糊化温度低于76℃的原料,生产的麻球品质较好。     

Physicochemical property changes in germinated brown rice flour from different storage periods of paddy rice

This study revealed that the storage duration (2, 4, 6, 8, 10 and 12 months) of paddy rice and pH (3 and 6.8) of steeping water during germination were significantly influenced the physicochemical properties of germinated brown rice flour (GBRF). GBRF obtained at pH 3 vs. 6.8 provided the highest both reducing sugar content and free gamma‐aminobutyric acid (GABA) content (99.8 vs. 54.2 mg per 100 g flour respectively) as the paddy rice was stored for 8 months. The peak viscosity of GBRF obtained at pH 3 and 6.8 exhibited the lower values than that of non‐GBRF throughout the storage. From the principal component analysis, reducing sugar had a positive correlation with α‐amylase activity whereas a negative correlation was found with peak viscosity. GBRF from paddy rice stored for 8 months and germinated at pH 3 possessed the highest free GABA content, 50 times of the non‐GBRF, which can be further utilised in functional and healthy foods.     

Physicochemical and organoleptic characteristics of seasoned beef patties with added glutinous rice flour

This study was conducted to determine if glutinous rice flour (GRF) could be a functional food additive to potentially replace corn starch (CS), soy protein isolate (SPI) and/or sodium tripolyphosphate (STPP) to improve the physicochemical and organoleptic characteristics of seasoned beef patties. GRF had a lower cook loss among the treatment groups due to an increase in fat and moisture retentions (p<0.05). GRF lowered texture profile values for hardness, gumminess, springiness, and chewiness (p<0.05) of the patties, which are generally beneficial for this product. The beef patties with GRF were juicier and more tender than the control and other treatments (p<0.05). Hedonic scores for juiciness, tenderness and overall acceptability were the highest for the beef patties with 1 and 3% GRFs, suggesting that GRF may be an effective functional ingredient to improve the textural quality of seasoned beef patties.     

膨化糙米粉添加量对面条特性的影响

将两种不同挤压条件制得的膨化糙米粉分别以0、10%、20%、30%、40%和50%的比例添加到小麦粉中,研究糙米粉添加量对面条蒸煮品质和质构性质的影响。结果表明,随着挤压膨化糙米粉(EBR)添加量的增加,面条干物质吸水率显著降低(P0.05),干物质损失率增加,干面条的折断强度先升高后降低,熟面条硬度、耐咀性、弹性等质构参数降低。添加由物料水分30%、挤压温度80℃、螺杆转速220 r/min条件下挤压制备的膨化糙米粉的面条干物质吸水率高而损失率相对较小,同时面条的硬度、咀嚼性以及弹性要高于添加由物料水分25%、挤压温度120℃、螺杆转速220 r/min条件下挤压制备的膨化糙米粉的面条。     

Physicochemical, mechanical and thermal properties of brown rice grain with various moisture contents

The effects of moisture content on the mechanical and thermal properties of either a short‐grain variety (Akitakomachi) or two long‐grain varieties (Delta and L201) of brown rice were studied. Total starch contents of the three varieties were comparable, but the amylose content of L201 was significantly higher than that of the other two varieties. The maximum compressive strength of brown rice grain was much higher than the maximum tensile strength. L201 showed the highest maximum compressive and tensile strengths. The phase transition temperatures (glass transition temperature T_g and melting temperature T_m) were examined by differential scanning calorimetry. The T_g and T_m for L201 were higher than those for Delta and Akitakomachi. The maximum compressive strength, maximum tensile strength, T_g and T_m for the three varieties of brown rice grains decreased with increasing moisture content. The T_g of individual brown rice kernels decreased from 53 to 22 °C as moisture content increased from 12 to 25% wet basis. A statistical model was calculated by using linear regression to describe the change in T_g in terms of moisture content.     

Physicochemical properties of rice flour as affected by alkaline soaking and washing treatments

Effects of alkaline [NaOH, saturated Ca(OH)₂ and/or limewater] soaking and subsequent washing (with water vs. without washing) treatments on physicochemical properties of rice flour were investigated. Alkaline soaking treatment generally caused a loss of granule angularity but some birefringence was observed for unwashed alkali-soaked flour granules. After soaking, protein content of the flours significantly (P < 0.05) decreased but swelling power significantly (P < 0.05) increased compared to the control (soaked in water). The washed flours had lower protein content than unwashed flours (3.77–6.87% vs. 5.26–7.87%). The NaOH-soaking treatment yielded higher swelling power and solubility, respectively, for unwashed and washed flours. Alkaline soaking increased breakdown but decreased pasting temperature, trough viscosity, final viscosity and setback of the paste compared to the control. Compared to the control, hardness of soaked flour paste was lower due to lower final viscosity and setback. Overall, physicochemical properties of rice flour could be modified by alkali-soaking and washing treatments.