酯化蜡质玉米淀粉对糯米粉团冷冻特性的影响

目的评价酯化蜡质玉米淀粉和预糊化酯化蜡质玉米淀粉对糯米粉团冷冻特性的影响。方法测定酯化蜡质玉米淀粉与预糊化酯化蜡质玉米淀粉的冻融稳定性;分别往糯米粉中添加1%、2%、3%、4%(m:m)4个比例的酯化蜡质玉米淀粉和预糊化酯化蜡质玉米淀粉制作速冻糯米粉团,检测速冻糯米粉团的失水率、裂口率、煮熟时间、糊汤率、感官评价等指标。结果预糊化酯化蜡质玉米淀粉与酯化蜡质玉米淀粉均具有良好的冻融稳定性,能有效降低速冻糯米粉团的失水率和裂口率,同时改善速冻糯米粉团的蒸煮和食味品质;预糊化酯化蜡质玉米淀粉在改善糯米粉团冷冻特性斱面效果更优,但两者差距不大,当预糊化酯化蜡质玉米淀粉的添加量为1%时,速冻糯米粉团的失水率为11.8%,裂口率为22.5%,煮熟时间为229 s,吸光度为0.823,感官及外观评分分别为79.3分、23.1分。结论添加1%预糊化酯化蜡质玉米淀粉制成的糯米粉团冷冻特性最好。     

Effect of Retrograded Waxy Corn Starch on Bread Staling

Waxy corn starch pastes (10%) were stored at 5 °C for up to 35 days, and the powder specimens of retrograded starches thus obtained were added to wheat flour for bread baking at a level of 5%. The effect of retrograded starch on the staling of bread was determined. The loaf which contained retrograded waxy corn starch, which was prepared by storing the 10% paste at 5 °C for 7 days, showed an increase in specific volume and the results of the sensory evaluation showed that it was very acceptable. During the storage of bread, the increase in firmness and decrease in degree of gelatinization were suppressed by adding retrograded waxy corn starch. The moisture content of bread crumbs did not relate to firmness. Added retrograded waxy corn starch decreased the final viscosity of flour. The crystalline region of retrograded waxy corn starch used for bread baking included longer chains from amylopectin which in raw starch occurred in the amorphous region.     

糯玉米淀粉对水饺皮品质的影响

为探究糯玉米淀粉对水饺皮品质的影响,研究不同糯玉米淀粉的添加量对生水饺皮色泽、强韧性、可冻结水的含量、微观结构及对冷冻前后水饺皮蒸煮品质的影响。结果表明：在生水饺皮的品质方面,添加糯玉米淀粉可显著提高生水饺皮亮度、强韧性、淀粉的结合程度并降低可冻结水的含量;在冷冻水饺皮的蒸煮品质方面,添加糯玉米淀粉可显著缩短水饺皮的蒸煮时间、降低蒸煮损失、提高剪切硬度并改善感官品质等,其中冷冻后的水饺皮面汤的透明度、蒸煮损失以及水饺皮的剪切硬度和咀嚼性优于未冷冻的水饺皮。因此,添加4%～6%的糯玉米淀粉可有效改善冷冻水饺皮的品质,为糯玉米淀粉在食品行业中的应用提供理论基础。     

Starch Cooking with Limited Water as Affected by Zein and Guar Gum

DSC (Differential Scanning Calorimetry) peak temperature of starch was decreased by adding zein, but was increased by adding guar gum. Adding zein increased the initial rate of starch cooking, but adding guar gum decreased it. Kinetic studies were carried out at 115, 125, and 135°C. At25°C, zein absorbed less water than waxy corn starch, especially at water activities >0.6 where guar gum absorbed more water than starch. The strong binding of water by guar gum increased DSC-peak-temperature and decreased the initial rate of starch cooking. The relatively weak binding of water by zein decreased DSC peak temperature and increased the initial rate of starch cooking. Although water sorption data at cooking temperatures are difficult to measure, the kinetic data at these temperatures and DSC data could be used to supplement the sorption data.     

Effect of the Addition of Common Bean (Phaseolus vulgaris L.) Flour on the In Vitro Digestibility of Starch and Undigestible Carbohydrates in Spaghetti

Abstract: Spaghetti is considered to be a slowly digestible starch food, a feature ruled by the particular physical properties of the product. Several studies have been reported to increase nutritional value of spaghetti, using legumes. We have studied the addition of common bean flour on the starch in vitro digestibility. Spaghetti was prepared with semolina and different concentrations of common bean flour (0%, 15%, 30%, and 45%, w/w). Proximate analysis, optimal cooking time, and cooking loss were estimated in crude spaghetti. Total, available, and resistant starches, indigestible fractions, and in vitro starch hydrolysis kinetics were accomplished in cooked spaghetti. Pasta with 30% and 45% of common bean flour showed higher values of protein. Particularly, the lowest cooking time was observed for composite spaghetti with 45% of common bean flour. There was a significant increase in cooking loss when common bean flour in the composite was added. Composite spaghetti samples with increasing common bean flour showed decreasing values of total starch but an important increase in the resistant starch (RS) level and indigestible insoluble fraction values. Plain pasta made with semolina showed the highest enzymatic hydrolysis rate, which decreased when common bean flour was added to the spaghetti. Spaghetti with a higher level of common bean flour was more slowly available, which may have positive implications for human health.     

Morphology of starch in surimi gels

 The purpose of this work was to study the changes undergone by starch during heat-induced surimi gel preparation either with or without added egg white, and their effects on the structure of gels using light and scanning electron microscopy. Gels were made from SA-grade Alaska pollack (Theragra chalcogramma) surimi with: (1) salt (3%, w/w); (2) salt and waxy corn starch (3% and 5%, respectively w/w); or (3) salt, waxy corn starch and egg white (3%, 5% and 5%, respectively, w/w). Final moisture was adjusted to 73% or 83%. The gels were prepared by prior setting (40°C, 30 min, followed by 90°C, 30 min) or cooking (90°C, 30 min). The prepared gel was frozen and stored at –20°C (±1°C) until analysis. Samples were observed by light and scanning electron microscopy. The results show that the starch granules alter according to the processing conditions, with the predominance of crystalline or amorphous morphology depending upon the availability of heat and water. Large cavities formed in the protein gel matrix during setting can trap water; as a result, water availability is limited for starch to swell and gelatinize even in the high-moisture gel. Received: 13 March 1997     

Synergistic Action of α-Amylase and Glucoamylase on Raw Corn

Optimum ratio of glucoamylase to α-amylase for synergistic hydrolysis of starch in corn flour was 1.8 AGU/1.0 KNU. The rate of hydrolysis of starch in dry milled corn was faster than that of waxy maize starch and wet processed corn. Hydrolysis of the starch in dry milled corn was the most efficient compared with that of wet milled, corn steeped in water or NaOH.     

蜡质玉米粉的糊化特性研究

为了解蜡质玉米粉及其不同制粉方法对糊化特性的影响,测定了干磨、湿磨、挤压制蜡质玉米粉以及蜡质玉米淀粉、糯米粉的溶胀度和RVA参数。结果表明:蜡质玉米粉糊化进程中溶胀度高,水合能力强,具有较高的糊化参数。不同品种蜡质玉米粉的破损值、谷值、峰值和终黏度的变异程度较大,蜡质玉米粉的峰值与谷值、终粘度和回生值、谷值与回生值、谷值与终粘度、终粘度与回生值均呈极显著正相关。湿法制粉糊化进程中水合能力强,主要RVA参数显著高于干法制粉和挤压制粉,具备很强的成糊能力和黏滞性,干法制粉成糊后稳定较好,抗老化性较强,挤压制粉的糊化进程不明显。     

Effect of Moisture Content on the Thermomechanical Behavior of Concentrated Waxy Cornstarch–Water Preparations— A Comparison with Wheat Starch

ABSTRACT: The rheological behavior of waxy cornstarch preparations at intermediate moisture contents (30 to 60% w/w) was studied by dynamic mechanical thermal analysis (DMTA). Differential scanning calorimetry (DSC) and electron spin resonance (ESR) experiments were also performed in parallel. The results were compared to those obtained previously for wheat starch. DMTA results evidenced a critical moisture content (between 50 and 55%) for waxy cornstarch that delimited a radical change in the rheological behavior both at room temperature and during heating. This critical water content was around 45% for wheat starch.     

蜡质玉米淀粉对糯米粉及速冻汤圆品质的影响

将蜡质玉米淀粉添加于糯米粉中制作速冻汤圆,考察蜡质玉米淀粉对糯米粉及速冻汤圆品质的影响.结果显示:蜡质玉米淀粉的添加能提高糯米粉的透明度,升高沉降值,同时降低糯米粉的峰值黏度和崩解值.蜡质玉米淀粉添加于糯米粉中制作速冻汤圆,使汤圆的高径比有所降低,冷冻失水率上升.加有蜡质玉米淀粉的速冻汤圆煮制后汤的透明度提高,质构特性...     

Effect of cooking time and ingredients on the performance of different starches in white sauces

The effect of white sauce ingredients and increased cooking time at 90 °C on the degree of gelatinization of corn, waxy corn, rice, potato and modified waxy corn starches was studied. The changes in pasting properties, linear viscoelastic properties, and microstructure were determined. In all the native starches in water, a longer cooking time at 90 °C caused greater starch granule swelling and more leaching of solubilized starch polymers into the intergranular space. These effects were more noticeable in the waxy corn and potato starches. The potato starch was the most affected, with complete disruption of the starch granules after 300 s at 90 °C. The microstructural changes which transformed a system characterized by starch granules dispersed in a continuous phase (amylose/amylopectin matrix) into a system with an increase in the continuous phase and a decrease in starch granules were associated with a decrease in system viscoelasticity. The elastic moduli were higher in the sauce than in the starch in water system. However, with the exception of potato starch, the white sauce showed lower viscoelasticity than the starch in water system. The white sauce ingredients decreased the effect of cooking time on the starch gelatinization process, particularly in potato starch.     

Rapid Visco-Analyzer (RVA) Pasting Profiles of Wheat,Corn, Waxy Corn,Tapioca and Amaranth Starches (A. hypochondriacus and A cruentus) in the Presence of Konjac Flour,Gellan, Guar,Xanthan and Locust Bean Gums

The Rapid Visco-Analyzer (RVA) 20min test was used to study the effects of different levels of konjac flour, guar, gellan, xanthan and locust bean gums on starch cooking properties. Wheat, corn, waxy corn, tapioca and A. hypochondriacus and A. cruentus starches were affected to different degrees by different levels of the gums. Peak viscosity increased at the higher gum concentrations, especially with locust bean gum at the 0.4 g level. The increase in viscosity was more pronounced with wheat and corn starches than with waxy corn and tapioca starches which consist mostly of highly branched amylopectin thus preventing close physical association between molecules. Amaranth starches showed much lower viscosity with all the gums than the other starches. Peak viscosity, time to reach the peak and maximum setback viscosity were affected by the gums. The increase in viscosity of starch/hydrocolloid systems is due to the release of amy-lose and low molecular weight amylopectin which promotes the formation of polymer complexes and significantly adds to the viscosity of the system.     

Spaghetti cooking quality of waxy and non‐waxy durum wheats and blends

Quality attributes of waxy durum wheat (Triticum turgidum L), milled semolina and cooked spaghetti were examined and compared with those of two non‐waxy durum cultivars. With the exception of kernel hardness, wheat quality characteristics were similar for both waxy and non‐waxy durum. Compared with average values obtained for durum wheat grown in North Dakota (USA) during the crop year 2000, the values obtained for the wheat used in this study were equal or better for most parameters evaluated. Semolina extraction for all samples was lower than the 2000 average of 62.6%. The waxy lines had higher ash, lower speck count, similar protein quantity, lower wet gluten and stronger mixograph curves than the non‐waxy cultivars. Waxy durum semolina had higher lipid content, starch damage, stirring number and flour swelling values. Spaghetti made from waxy durum semolina had shorter cooking time, similar cooking loss and cooked weight and lower firmness values, which would be unacceptable by most standards. Spaghetti made from blends containing 20–80% waxy durum semolina were evaluated. Cooking time and firmness decreased and cooking loss increased as the amount of waxy semolina increased. Acceptable spaghetti was obtained using 20–40% waxy semolina blends, depending on the quality of the non‐waxy blending material. Copyright © 2004 Society of Chemical Industry     

Kinetics of Phase Transition of Waxy Corn Starch at Extrusion Temperatures and Moisture Contents

Thermal energy effect on the phase transition of a waxy corn starch, Amioca, with different amount of water was evaluated by using differential scanning calorimetry. For water content less than 40% (w/ w), the kinetics of the conversion of starch followed the pseudo-zeroth order. An activation energy of 33.78 kcal/mol for 80% Amioca and that of 44.25 kcal/mol for 75% Amioca in the Amioca-water system were obtained from the Arrhenius relation. A useful correlation between the rate constant of conversion and a nondimensional temperature parameter, T/T_p, was found from various sources and with various moisture contents.     

Wheat batter physical properties as influenced by starch/flour types and egg contents

Batter liquid–solid phase interactions can play a critical role in determining the functionality, including adherence, appearance and texture of end use coated product. Batter chemical composition is a key factor affecting batter characteristics. The effect of substituting wheat flour with fractions of rice flour, native corn starch, modified waxy corn starch, tapioca starch and lupine flour ranging from 26 to 56% of the solid phase and egg levels ranging from 6 to 35% of the liquid phase on the rheological properties of batter systems was studied. Results indicated that lupine flour had the greatest water holding capacity (WHC) ranging from 93.9 to 119.3% of various lupine flour percent to egg levels used. Flow behaviour index of batter flour treatments ranged from 0.91 to 1.87; values that were significantly (P?<?0.05) greater than a 100% control wheat flour. Consistency coefficient of treatments ranged from 0.01 to 0.37 mPa sⁿ; values that were significantly lower than wheat flour (i.e., 5 mPa sⁿ). Egg level used in this study had minimal effect on treatment rheological properties. The changes in WHC and viscoelastic properties of treatments were attributed to changes in protein and fibre contents and structure as a result of replacing wheat flour with starch/flour. Protein–starch–lipid matrix formation and variation in water absorption kinetics of treatments most probably wrought batter functionality. The increase in pasting properties with the increase in starch/flour contribution suggested an increased contribution of starch in forming a net effect of batter treatments pasting viscosities. Results of this study provide vital information for the potential use of starch types to enhance the rheological properties of coating applications including adhesion and water holding capacity of substituted batter treatment.     

Extracted Lipids and Carbohydrates During Washing and Boiling of Milled Rice

Washing and cooking of waxy and nonwaxy milled rice and rice flour resulted in extraction of lipids, and carbohydrates, principally starch and nonstarch polysaccharides. Lipids, nonstarch polysaccharides and amylose contributed to hardening of waxy rice (IR 29) starch gel consistency in H₂O. Lipids extracted were mainly nonstarch lipids, principally free fatty acids. Nonstarch polysaccharides extracted in cold water were rich in glucose, galactose and arabinose, but those extracted in hot water were mainly glucans. Hot water extractable starch was more in waxy than in nonwaxy rice but complexed less with IR 29 amylopectin.     

高直链玉米淀粉添加对挤压荞麦面条结构、蒸煮品质及消化特性的影响

制备挤压荞麦面条,研究不同添加量（10%、20%、25%、30%）的高直链玉米淀粉（m/m,基于全粉）对挤压荞麦面条结构、蒸煮品质及消化特性的影响。结果表明,随着高直链玉米淀粉添加量的增加,挤压面条直径减小,糊化度降低。X射线衍射结果表明添加高直链玉米淀粉后,面条除了V型结晶峰外还存在未完全糊化的直链淀粉的典型B型峰。热力学性质结果也表明直链淀粉发生部分糊化。添加高直链玉米淀粉后,面条色泽变浅变亮,最佳蒸煮时间缩短,蒸煮损失率由9.90%增加到12.43%。当高直链玉米淀粉添加量为25%时,面条开始出现断条。面条硬度由2 105.709 g显著增加至3 680.401 g,弹性由0.961降低至0.866。扫描电镜结果表明,随着高直链玉米淀粉添加量的增加,致密的面条结构逐渐出现裂纹,且面条截面有较多未完全糊化的淀粉颗粒。淀粉体外消化实验表明,随着高直链玉米淀粉添加量的增加,淀粉水解率逐渐下降,预计血糖指数减小,抗性淀粉含量增加。当高直链玉米淀粉添加量为30%时,挤压荞麦面条的预计血糖指数从74.28降至66.31,抗性淀粉含量从34.43%增加至47.86%。     

变性淀粉对速冻水饺质量的影响

分析不同原料(蜡质玉米淀粉、木薯淀粉和马铃薯淀粉)制备的羟丙基淀粉的性能,并将羟丙基蜡质玉米淀粉,羟丙基木薯淀粉和羟丙基马铃薯淀粉分别添加到面粉中,研究其对速冻水饺品质的影响。实验表明:变性淀粉添加量为3%～4%(以面粉干基计),面团含水量为44%～45%时,速冻水饺的冷藏稳定性最好。其中添加羟丙基蜡质玉米淀粉在减少速冻水饺的冻裂率,改善速冻水饺的透明度、光泽和色泽方面效果最明显。     

The effect of extrusion cooking using different water feed rates on the quality of ready-to-eat snacks made from food by-products

The effect of different levels of feed moisture (12–17%) during extrusion cooking, using a co-rotating twin-screw extruder on selected nutritional and physical properties of extruded products was investigated. Four different formulations were used based on wheat flour and corn starch with the addition of 10% brewer’s spent grain (BSG) and red cabbage (RC) trimming reducing the flour and starch. The samples were: wheat flour + BSG (WBSG), corn starch + BSG (CBSG), wheat flour + red cabbage (WRC) and corn starch + red cabbage (CRC). Process conditions utilised were: constant feed rate of 25 kg/h, screw speed 200 rpm and barrel temperature of 80 and 120 °C. The results indicated that increasing the water feed to 15% increased the level of total dietary fibre (TDF) in all the extrudates while extrusion processing increased the level of TDF in WBSG, CBSG and CRC but decreased in WRC products. Extrusion cooking increased the level of total antioxidant capacity (TAC) and total phenolic compounds (TPC) in WRC and CRC. In addition to water feed level affecting the TDF of the extrudates, also affected were the expansion ratio, bulk density, hardness, WSI, SME and colour. The protein level of the products and hardness of extrudates were related to the different formulations.     

Some Properties of Amaranthus paniculatas (Rajgeera) Starch Pastes

The lysine rich high protein seeds of A. paniculatas (Rajgeera) are reported to contain 50–60% of waxy starch, concentrated in the endosperm. However its food related properties are comparatively unknown. In the present work, paste viscosity, paste clarity, freeze-thaw stability and effect of shear on the viscosity of A. paniculatas starch paste have been studied and compared to corn starch. Also included are the stability of Rajgeera starch paste under pressure cooking (30 min, 15 lb pressure) and acidic conditions (pH 6.98—1.76). Rajgeera starch was found to have a higher paste viscosity, lower paste clarity and high freeze-thaw stability than corn starch. Both Rajgeera and corn starch underwent thinning on being subjected to mechanical shear. Rajgeera starch withstood pressure cooking conditions admirably, but was found to be sensitive to acidic conditions.