变性淀粉对非发酵面团冻融品质的影响

为了探究变性淀粉对非发酵面团冻融品质的影响,本研究比较了在添加马铃薯羟丙基二淀粉磷酸酯、木薯醋酸酯淀粉、木薯羟丙基淀粉与马铃薯醋酸酯淀粉后非发酵面团冻融品质的变化。结果表明：变性淀粉未能有效控制冻融面团的失水率,但冻融面团深层结合水相对含量均有所增加,凝胶能力下降,且不受变性淀粉添加量与种类的影响。冻融面团剪切力均随着变性淀粉添加量增加呈现“下降-上升”的趋势,且均低于对照组。变性淀粉添加量较少时基本能较好地改善熟面坯的质构特性,高添加量反而不利于熟面坯的质构特性。添加木薯醋酸酯淀粉不利于面团流变性的改善,而其余3 种变性淀粉在添加量较低（＜5%）时,有利于改善面团的流变特性。因此,变性淀粉在添加量较少时对非发酵面团冻融品质有一定的改良作用。     

变性淀粉对冷冻面团水分特性的影响

探讨了醋酸酯马铃薯淀粉对冷冻面团水分特性的影响。面团中分别添加不同量的醋酸酯马铃薯淀粉,利用脉冲核磁共振仪测定面团特水力。结果表明:醋酸酯马铃薯淀粉显著增加了冷冻面团持水力,且持水力随醋酸酯马铃薯淀粉添加量的增加而增大;添加量为15%时,持水力达到最大值;与淀粉面团相比,醋酸酯马铃薯淀粉面团中不可冻结水的相对面积增大,不可冻结水的弛豫时间显著降低,这表明添加醋酸酯马铃薯淀粉减弱了水分子的移动性,使面团中水分相对难冻结,减轻了面团冻结过程中的结构损伤。     

变性淀粉对冷冻面团面包品质的影响

以木薯淀粉为原料,主要研究了预糊化淀粉、羟丙基二淀粉磷酸酯和乙酰化二淀粉磷酸酯三种变性淀粉的物化特性与冻融稳定性,以及它们对冷冻面团面包比容及面包全质构的影响。实验结果表明:木薯淀粉经过不同方式的变性后,物化特性差异很大,其中,羟丙基二淀粉磷酸酯的冻融稳定性最好,预糊化淀粉的冻融稳定性最差;添加5%三种变性淀粉后均能显著延缓冷冻面团的下降趋势,并对冷冻面团面包的品质具有良好的改善作用。这一结果与变性淀粉冻融稳定性及冷冻面团面包比容变化趋势一致,进一步表明变性淀粉,尤其是羟丙基二淀粉磷酸酯可以有效抑制冷冻面团内部水分的迁移,降低冻藏过程中冰晶和重结晶的形成,从而改善冷冻面团面包的内部质构。     

两种羟丙基淀粉对速冻饺子品质影响

研究两种不同原料(马铃薯和木薯)羟丙基淀粉对面粉溶剂保持能力及速冻饺子皮烹煮损失率、色泽、水分含量和微观结构影响.结果表明,随羟丙基淀粉添加量增加,配粉对乳酸保持能力(乳酸SRC值)逐渐降低,面筋强度弱化;随马铃薯羟丙基淀粉添加量增加,配粉对水保持能力(水SRC值)升高;而木薯羟丙基淀粉对面粉水SRC值无显著影响.添加...     

醋酸酯变性淀粉对低筋面团热机械学特性的影响

将荞麦粉与小麦粉以6∶4比例混合,制成低筋粉,再将马铃薯醋酸酯淀粉及木薯醋酸酯淀粉按不同比例分别添加到低筋粉中,利用Mixolab混合仪研究两种醋酸酯变性淀粉对低筋粉形成的面团流变及糊化特性的影响.结果表明:两种醋酸酯淀粉都可显著的增强面团的强度及蒸煮稳定性(p＜0.05),木薯醋酸酯淀粉可延长面团的形成和稳定时间、减小机械弱化值,而马铃薯醋酸酯淀粉会降低面团的吸水率及热弱化值.     

羟丙基交联木薯淀粉对面团特性及挂面品质的影响

研究了羟丙基交联木薯淀粉对面团特性及挂面品质的影响,结果表明,羟丙基交联木薯淀粉可有效改善面团的面筋特性、粉质、拉伸和糊化特性,使面团的吸水率增大,提高糊化黏度和峰值时间,降低糊化温度、回生值和衰减值;添加0％～ 1.2％的羟丙基交联木薯淀粉可有效提高面团的面筋指数、稳定时间、拉伸能量、延伸度和拉伸阻力,降低弱化度;添加0％～0.8％的羟丙基交联木薯淀粉可有效延长面团的形成时间;添加羟丙基交联木薯淀粉可提高挂面的白度和亮度,增加挂面的弹性、硬度,改善挂面的烹煮品质;添加0％～1.2％的羟丙基交联木薯淀粉可有效改善生挂面的断裂强度,提高感官品质.综合分析,在本试验条件下,确定羟丙基交联木薯淀粉的最佳添加量为1.2％.     

亚麻多糖对薯类改性淀粉糊化特性和冻融稳定性的影响

利用快速黏度分析法、质构分析法、冻融循环等方法探讨自然条件下食盐、糖、酸或碱等环境中亚麻多糖对3种薯类改性淀粉糊化特性及冻融稳定性的影响。试验结果表明:自然条件下,亚麻多糖显著增强马铃薯醋酸酯淀粉、木薯醋酸酯淀粉、木薯羟丙基二磷酸酯淀粉的膨胀力,降低热稳定性,使木薯羟丙基二磷酸酯淀粉的凝胶结构更加紧密,提高木薯羟丙基二磷酸酯淀粉的冻融稳定性。在盐、糖环境中,亚麻多糖均能增强马铃薯醋酸酯淀粉、木薯醋酸酯淀粉、木薯羟丙基二磷酸酯淀粉的膨胀力,降低热稳定性,提高冻融稳定性。亚麻多糖可提高薯类改性淀粉在酸性或碱性条件下的膨胀力,改善薯类改性淀粉在酸性条件下的冻融稳定性。     

羟丙基木薯淀粉对冷冻鱼丸水分特性的影响

在鱼丸中添加羟丙基木薯淀粉,以不添加淀粉和添加木薯原淀粉为对照和对比,用真空烘干法、核磁共振和差示扫描量热为研究方法,研究羟丙基木薯淀粉对冷冻鱼丸中水分特性的影响。结果表明,淀粉糊化膨胀后填充到鱼丸肌原纤维蛋白网格中,有利于束缚鱼丸中的结合水和束缚水,降低水分的移动性,同时提高了鱼丸的总水分含量,而减少了冻融过程的水分损失。羟丙基淀粉分子中羟丙基基团的引入会阻止其本身的联接,同时增强淀粉分子无定型区的吸水能力,进而增强淀粉颗粒的水合作用和膨胀度,因此相对于添加原淀粉,添加羟丙基木薯淀粉的鱼丸有更好的保水性和束缚性。此外,差示扫描量热表明,鱼丸中添加羟丙基木薯淀粉有利于冷冻时冰晶的分布均匀和细小,减少低温给鱼丸带来的破坏作用和鱼丸解冻后汁液的流失。     

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。     

变性淀粉影响冷冻春卷皮品质的研究

比较系统地分析了变性淀粉的种类及添加量对冷冻春卷皮的加工及感官品质的影响。结果表明:以面浆的黏度为评价依据时,β-环状糊精、羟丙基二淀粉磷酸酯、预糊化淀粉和醋酸酯淀粉的最适添加量分别为1%、1.5%、2%和5%;这4种变性淀粉均可改善春卷皮的冻藏失水率,其中1%的β-环状糊精效果最好;变性淀粉在面浆中的应用可以明显改善春卷皮的硬度及拉伸特性。变性淀粉可明显降低春卷皮的可冻结水的含量。从感官评价的角度看,1%的β-环状糊精可显著改善春卷皮的表皮色泽和外部形状。     

Bread quality of frozen dough substituted with modified tapioca starches

Rheological properties of dough and bread quality of frozen dough-bread containing 18.4% of hydroxypropylated (HTS), acetylated (ATS), and phosphorylated cross-linked (PTS) tapioca starch with different degrees of modification and 1.6% of dried powdered gluten were compared to the same amount of native tapioca starch (NTS) or wheat flour-bread. Doughs substituted with native or modified tapioca starches had the same mixing tolerance as 100% wheat flour. The dough was frozen and stored for 1 week at −18°C, and thawed (one freeze-cycle). The amount of freezable water in the dough substituted with native or modified tapioca starches was not significantly different from that of wheat flour. Frozen dough-bread substituted with highly modified HTS (degree of substitution; DS 0.09–0.11) retarded bread staling, while lowly modified HTS (DS 0.06–0.07) or ATS (DS 0.02–0.04), and PTS (0.004–0.020% phosphoryl content) substitution fastened bread staling as compared with frozen dough-bread baked from wheat flour. The breadcrumbs containing HTS and ATS felt tacky, whereas the bread containing PTS was dry feel. HTS and ATS swelled and collapsed easily during heating, while PTS was difficult to swell and disperse as compared with NTS, therefore the gelatinization properties seemed to affect the texture of bread. Breadcrumb containing HTS showed small firmness during storage, and highly modified HTS-h (DS 0.1) was the smallest. This means highly hydroxypropylated tapioca starch significantly retards bread staling. Staling properties and texture of frozen dough-bread with various tapioca starches were the same as conventional bread baked with the same amount of tapioca starches. These results suggest that a one freeze–thaw cycle and a 1-week frozen period do not change characteristics of starch, gelatinization and retrogradation properties as compared with the conventional method, and the highly modified HTS-h is prominent anti-staling food-stuff in frozen dough.     

Effect of modified tapioca starch and xanthan gum on low temperature texture stability and dough viscoelasticity of a starch-based food gel

This work investigated the effect of modified tapioca starch and xanthan gum on dough viscoelasticity and texture stability during storage at 4 °C of starch sheets for Chinese shrimp dumplings. Hydroxypropylated starch and hydroxypropylated-crosslinked starch were used to substitute for tapioca starch in the control formulation, and xanthan gum was added to adjust the formulation. During storage, texture of the control became firmer due to amylopectin retrogradation confirmed by differential scanning calorimetry and X-ray diffraction. Conversely, gel sheets containing modified starches showed less texture change. Dough viscoelasticity of the formulations substituted by hydroxypropylated starch were much softer and easier to deform than that of the control one. Dough with hydroxypropylated-crosslinked starch was, however, stiffer and more strain-resistant. Moreover, the formulation comprising the mixture of both types of modified starches and xanthan gum gave dough viscoelasticity similar to that of the control, and provided gel sheet the least texture change. Consequently, this modified formulation could be beneficial for the application of frozen/chilled dumpling wrappers.     

Effect of Starch Modifications and Hydrocolloids on Freezable Water in Cassava Starch Systems

The effect of starch chemical modifications and hydrocolloids on the proportion of freezable water in starch gels at various moisture contents was studied. The proportion of freezable water increased with moisture content, from less than 6.1% to 84.9% (w/w) of the water fraction between 30% and 70% moisture content (wet weight basis, wwb). A transition between limited and excess water conditions was identified in the range 30‐40% moisture content (wwb), whereby the proportion of freezable water markedly increased from 6.1% to 40.4% (w/w) of the water fraction, in the case of the non‐modified starch control. At 30 and 40% moisture content (wwb), gels made of acetylated starch and hydroxypropylated starch had a significantly lower amount of freezable water than the control, in particular at 40% moisture content (wwb) the amount of freezable water was reduced from 40.4% to 15.3‐25.7% (w/w) of the water fraction. In systems with 50% moisture content (wwb) or higher, modified starches did not show a significant reduction in freezable water compared to the control. Two hydrocolloids, xanthan and carboxymethyl cellulose (CMC) used in a 40% moisture content (wwb) starch system significantly reduced freezable water from 40.4% to 23.9‐24.1% of the water fraction (w/w), at a hydrocolloid: starch ratio of 1:14 (w/w). The linear decrease in the freezable water proportion with xanthan and CMC concentration pointed to the absence of interactions between the starch and hydrocolloid fractions. Therefore, combinations of hydroxypropylated or acetylated starches and xanthan or CMC may be used to control freezable water, particularly in frozen food products with moisture contents around 40% (wwb).     

Retrogradation of Starch Mixtures Containing Rice Starch

ABSTRACT: Different starches often coexist in food systems. Starch retrogradation is the primary reason for quality deterioration of a food system during storage. This article addresses the retrogradation behaviors of several starch mixtures containing normal rice starch (NRS). Potato starch, tapioca starch, waxy corn starch, hydroxypropylated potato starch, hydroxypropylated tapioca starch, and acetylated tapioca starch were mixed with NRS. Starch suspensions were gelatinized and the relative solid content, (S′) measured by pulsed nuclear magnetic resonance, was used to characterize the retrogradation behavior of starch systems. The retrogradation behaviors of starch mixtures can be divided into two categories according to the additive or non‐additive nature of S′, for which the concept “regional moisture content” was introduced.     

沙蒿胶提高冷冻面团抗冻性及其抗冻机理的探讨

本文主要研究了沙蒿胶对冷冻面团品质的影响，并将其作用效果与刺槐豆胶进行了比较。采用拉伸仪、差示扫描量热仪、扫描电镜分别测定了空白面团（未添加任何胶体的冷冻面团）和添加沙蒿胶面团在冷冻储藏1、2、3、4w后抗拉伸性能、可冻结水含量以及微观结构的变化，同时比较了添加沙蒿胶和刺槐豆胶后上述参数的不同。结果表明：（1）随着冷冻储藏时间延长，面团的抗拉伸阻力逐渐减小，而面团的延伸性却逐渐增：赶；当冷冻储藏时间相同时，添加沙蒿胶面团的抗拉伸阻力最大，其次是添加刺槐豆胶面团的抗拉伸阻力，最差的是空白面团的抗拉伸阻力；相对应添加沙蒿胶面团的延伸性最小，其次是添加刺槐豆胶面团的延伸性，最大的是空白面团的延伸性。（2）随着冷冻储藏时间延长，面团可冻结水含量逐渐增大；在同～冷冻储藏时间时，含沙蒿胶和刺槐豆胶面团中的熔化焓均小于空白面团，其中含刺槐豆胶面团的熔化焓最小，但在冷冻储藏4w时，两者基本相同。（3）冷冻储藏2w后，含沙蒿胶和刺槐豆胶面团中面筋蛋白胶束的破坏程度均减小，而沙蒿胶的作用效果明显强于刺槐豆胶。     

木聚糖酶对冷冻面团和馒头品质的影响

本实验研究了木聚糖酶对冻藏1d、7d、14d的冷冻面团和馒头品质特性的影响;并采用差示量热扫描仪(DSC)测定了冷冻面团的可冻结水(冰)含量,讨论了木聚糖酶改善冷冻面团品质的热力学机制。研究结果表明,随着冻藏时间的延长,面团的发酵力、酵母存活率、馒头比容、抗老化能力均呈现一定的下降趋势;在相同的冻藏时间下,木聚糖酶对面团的发酵特性和馒头品质改善作用明显;木聚糖酶含量为80mg.kg_-1时,可冻结水(冰)含量最低;添加木聚糖酶后,冰晶颗粒更加细小均匀。这说明适量的木聚糖酶能够有效地降解水不溶性阿拉伯木聚糖,使更多的水分保留在面筋网络结构中,从而抑制低温面筋网络结构和酵母细胞的破坏作用,改善馒头品质。     

Effect of β‐Glucan–Rich Barley Flour Fraction on Rheology and Quality of Frozen Yeasted Dough

Research has shown that prolonged frozen storage of bread dough reduces the quality of the end product. In this study, the effect of air‐classified barley flour fraction rich in β‐glucan (approximately 25%) on rheology and quality of frozen yeasted bread dough was investigated. Wheat flour (W) was replaced by air‐classified barley flour fraction (B) at 10% without or with 1.4% vital gluten to produce β‐glucan enriched barley dough (WB) or barley dough plus gluten (WB + G). Dough products were stored at ?18 ºC for 8 wk and their rheological properties were investigated weekly. During frozen storage dough extensibility increased, while elastic and viscous moduli decreased. Differential scanning calorimeter and nuclear magnetic resonance data indicated that WB and WB + G dough products contained approximately 10% less freezable water and 9% more bound water compared to the control dough (W). β‐Glucan enriched dough also exhibited less changes in gluten network as shown by SEM photographs. The addition of air‐classified barley flour fraction at 10% in frozen dough reduced deterioration effects caused by frozen storage via minimizing water redistribution and maintaining rheological properties of frozen dough.     

Dynamic rheological properties of rice flour‐starch blends

The dynamic rheological properties of blends of rice flour (RF) with six different commercial starches (sweet potato starch, potato starch, tapioca starch, waxy corn starch, hydroxypropylated potato starch, and hydroxypropylated tapioca starch) were evaluated. The magnitudes of storage modulus (G′) of all blend samples were higher than those of loss modulus (G′′) over most of the frequency range (0.63–62.8 rad · s⁻¹). In general, the dynamic moduli results of all blend samples showed that changes in G′ values were relatively greater than changes in G″ values after adding the starches when compared to RF. tan δ (ratio of G′′/G′) values (0.21–0.22) of the RF‐potato starch and RF‐hydroxypropylated potato starch blends were much lower than those (0.25–0.33) of other blends and RF, indicating that there is a more pronounced synergistic effect on the elastic properties of RF‐starch blend systems in the presence of potato starches.