薯类淀粉对兔肉肉糜流变性质和凝胶特性的影响

探讨木薯淀粉、甘薯淀粉和马铃薯淀粉对兔肉肉糜流变性质和凝胶特性的影响,研究了不同淀粉添加量时,兔肉肉糜弹性模量G'、质构特性、凝胶强度、保水性和色泽的变化规律。结果表明:升温过程中,兔肉肉糜的弹性模量G'经历了3个阶段的变化。首先在40~50℃,G'缓慢上升,接着在50~57℃,G'急剧下降,然后在57~80℃,G'快速上升,之后趋于稳定。降温过程中,G'逐渐升高。淀粉对兔肉肉糜在升温和降温过程中弹性模量的变化影响显著。添加淀粉能增加兔肉肉糜凝胶的硬度、胶着性和咀嚼性,降低其内聚性,而弹性则呈现先上升后下降的趋势。添加淀粉能增加兔肉肉糜的凝胶强度、持水性,同时降低压力失水率,同一添加量时,马铃薯淀粉对改善兔肉肉糜凝胶的品质、增加肉糜凝胶保水性的效果最好。添加淀粉能增加肉糜凝胶的亮度值和白度值,降低肉糜凝胶的黄度值,但淀粉的种类和添加量对兔肉肉糜凝胶的色泽影响不显著。3种薯类淀粉中,马铃薯淀粉的应用效果最好。     

薯类淀粉糊在超声场中凝胶质构特性研究

以木薯淀粉、红薯淀粉以及马铃薯淀粉为研究对象,研究了不同浓度、不同超声场作用时间、功率和温度对淀粉糊凝胶质构特性的影响。结果表明,在相同浓度下,马铃薯淀粉糊凝胶强度、压缩功和黏附性显著高于木薯淀粉和红薯淀粉。3种薯类淀粉糊经超声场作用后,淀粉糊质构特性发生显著变化,凝胶强度均呈降低趋势。超声波处理能有效改变薯类淀粉糊质构特性,超声作用对不同薯类淀粉糊的影响存在显著差异。     

7种特色根茎类淀粉的流变与凝胶特性研究

为拓宽中国南方特色根茎类淀粉的应用途径,选取了木薯淀粉为对照,对淮山淀粉和香芋淀粉等根茎类淀粉的糊化、流变和凝胶特性进行了比较研究。结果表明,不同作物间淀粉的流变与凝胶特性差异显著,而不同作物品种间差异相对较小。各淀粉均在69.77～84.37℃时开始糊化,淮山淀粉和香芋淀粉的糊化温度、峰值时间均大于木薯淀粉。木薯淀粉的崩解值高于淮山淀粉和香芋淀粉。7种根茎类淀粉的弹性模量和黏性模量均随频率增加而增加,且损耗角正切值(tanδ)1,表现出典型的弱凝胶动态流变学图谱。香芋淀粉和木薯淀粉的凝胶强度、硬度、胶黏性相近,且显著低于淮山淀粉。木薯淀粉凝胶的弹性、内聚性均大于淮山淀粉和香芋淀粉。     

马铃薯淀粉和豌豆淀粉复配体系的流变与凝胶特性研究

以马铃薯淀粉和豌豆淀粉按照一定的比例进行复配,采用动态流变仪和质构仪测定复配体系的糊化、流变特性及凝胶强度。结果表明:复配体系的糊化温度随着马铃薯淀粉比例的增大而有所下降,由70.1℃降低到64.6℃;在淀粉质量分数为6%的体系中,马铃薯淀粉和豌豆淀粉的比例为1∶5和1∶11时复配体系的弹性模量G′较大(分别为810.1 Pa和814.7 Pa),而在比例为1∶3或1∶5时复配体系的粘性模量G″较大(分别为41.0 Pa和41.6 Pa);马铃薯淀粉和豌豆淀粉的比例为1∶5和1∶11时复配体系的Tanδ较小,此配比的两个复配体系具有较好的凝胶形成能力,且凝胶强度较大(98.5~100.1 g)。      

马铃薯淀粉和豌豆淀粉复配体系的流变与凝胶特性研究

以马铃薯淀粉和豌豆淀粉按照一定的比例进行复配,采用动态流变仪和质构仪测定复配体系的糊化、流变特性及凝胶强度。结果表明:复配体系的糊化温度随着马铃薯淀粉比例的增大而有所下降,由70.1℃降低到64.6℃;在淀粉质量分数为6%的体系中,马铃薯淀粉和豌豆淀粉的比例为1∶5和1∶11时复配体系的弹性模量G′较大(分别为810.1 Pa和814.7 Pa),而在比例为1∶3或1∶5时复配体系的粘性模量G″较大(分别为41.0 Pa和41.6 Pa);马铃薯淀粉和豌豆淀粉的比例为1∶5和1∶11时复配体系的Tanδ较小,此配比的两个复配体系具有较好的凝胶形成能力,且凝胶强度较大(98.5~100.1 g)。     

薯类淀粉与卡拉胶共混体系特性及其对肌原纤维蛋白凝胶特性的影响

为研究薯类淀粉与亲水性胶体(卡拉胶)之间的相互作用机理及其对肌原纤维蛋白的流变与质构的影响,以马铃薯淀粉、红薯淀粉、木薯淀粉以及混合淀粉(木薯:红薯:马铃薯=1:1:1)为原料与卡拉胶进行不同比例复配,测定卡拉胶对薯类淀粉静态流变、凝胶质构、冻融稳定性以及热力学回生特性的影响。静态流变学实验表明,薯类淀粉与卡拉胶共混体系属非牛顿流体,具假塑性流体特征,卡拉胶的加入增大了体系的表观黏度,在配比为8:2时达到最大。冻融稳定性实验表明,卡拉胶添加量越大,体系析水率越小,冻融稳定性越好;随冻融循环次数的增加,析水率变大。此外,淀粉与卡拉胶配比为9:1时,淀粉的回生率最小。将薯类淀粉/卡拉胶共混体系应用到鸡胸肉肌原纤维蛋白中发现,淀粉、卡拉胶/肌原纤维蛋白共混体系具明显剪切稀化现象,淀粉与卡拉胶的加入增强了肌原纤维蛋白触变性和表观黏度,改善了凝胶质构特性,使得体系的硬度、弹性、粘聚性和咀嚼度都得到了提升。本研究为促进薯类淀粉在肉制品中的应用,及薯类淀粉的开发利用提供一定理论依据。     

酸改性淀粉流变特性及凝胶化性质的研究

本文比较研究了几种不同原淀粉及改性淀粉的流变特性及凝胶化性质，包括：淀粉糊性质的研究，温度、浓度、PH对淀粉糊表观粘度的影响，淀粉凝胶强度及凝胺质构的研究等。结果表明：酸踟性淀粉具有低粘度、高浓度下稳定的凝肢性、并具有良好的咀嚼性和弹性，可以在食品工业中广泛应用的一种良好的食品胶凝剂。     

表观直链淀粉含量对小麦淀粉凝胶流变特性影响的研究

探讨表观直链淀粉在小麦淀粉凝胶的流变学特性中的作用,寻找表观直链淀粉含量与流变特性参数间的相关性。运用动态流变仪对9种不同品种小麦淀粉的糊化和短期回生进行分析,找出流变特性参数,并运用SPSS分析其相关性。在表观直链淀粉含量相差较大的情况下,结合糯小麦淀粉来考察,直链淀粉对于升温、降温、时间扫描和频率扫描等过程的流变特性有着重要的影响;当直链含量相差较小时,在8个普通小麦品种间,直链淀粉对与降温过程和凝胶形成强度有着决定性的影响。在整个短期回生过程中,表观直链淀粉含量直接决定凝胶的流变特性,但是在表征流变特性上有一定的局限性。     

淀粉纳米颗粒在不同增塑剂中的糊化与流变特性研究

本文以蜡质玉米淀粉为原料,经普鲁兰酶酶解脱支,短直链淀粉重结晶制取淀粉纳米颗粒(SNPs)。采用差示扫描量热仪(DSC)和动态流变仪,探究了不同浓度SNPs在甘油、山梨糖醇、葡萄糖水溶液中的热特性、回生特性以及流变特性的变化规律。DSC测试表明,添加山梨糖醇、葡萄糖和甘油溶液(其与水比例为1:1)后,SNPs的起始糊化温度分别增加了10.85℃、10.96℃和15.02℃,SNPs的终止糊化温度分别增加了9.29℃、9.17℃、12.40℃。回生结果表明,增塑剂会抑制SNPs的回生。随着浓度增加,SNPs在增塑剂体系中储能模量明显增加,且损耗模量大于储能模量,凝胶性增强。20%SNPs在山梨糖醇溶液和甘油溶液中的储能模量是10 Pa·s左右,而在葡萄糖溶液中大于1000 Pa·s,在葡萄糖溶液中损耗模量在100~500 Pa·s,说明SNPs葡萄糖水溶液具有更强的凝胶性。本文为SNPs在不同增塑剂中制备可降解膜提供理论依据。     

马铃薯淀粉糊化及凝胶特性研究

采用快速黏度分析仪(rapid viscosity analyzier,RVA)测定淀粉浓度、pH、蔗糖、柠檬酸、卡拉胶等对马铃薯淀粉糊化特性和凝胶特性的影响.结果表明:随着淀粉浓度的增加,马铃薯淀粉糊的热稳定性和凝沉性变差,凝胶性增强,容易回生;在pH 7时马铃薯淀粉的热稳定性、凝沉性和凝胶性较差,马铃薯淀粉不易回生;添加蔗糖、卡拉胶、明矾、食盐或苯甲酸钠,马铃薯淀粉的热稳定性、凝沉性、凝胶性增强;添加柠檬酸后马铃薯淀粉的热稳定性和凝沉性增强,凝胶性减弱.     

Some properties of potatoes and their starches II. Morphological,thermal and rheological properties of starches

The physico-chemical, morphological, thermal and rheological properties of the starches separated from different potato cultivars (Kufri Jyoti, Kufri Badshah and Pukhraj) were studied. The starches separated from the mealier cultivars (Kufri Jyoti and Kufri Badshah) showed lower transition temperatures (T_o; T_p and T_c), peak height indices (PHI), and higher gelatinization temperature range (R) and enthalpies of gelatinization (ΔH_gel) than the starch from the least mealy cultivar (Pukhraj). Swelling power, solubility, amylose content and transmittance values were observed to be higher for Kufri Jyoti and Kufri Badshah potato starches, while turbidity values were lower for these starches. The rheological properties of starches, measured using a dynamic rheometer, showed significant variation in the peak G′, G″ and peak tan δ values. Kufri Badshah and Kufri Jyoti starches showed higher peak G′, G″ and lower peak tan δ values than Pukhraj starch during heating and cooling cycles. Kufri Jyoti and Kufri Badshah starches showed higher breakdown in G′ than starch from the Pukhraj potato cultivar. The large-sized granules of the starches from Kufri Badshah and Kufri Jyoti appeared to be associated with higher values of peak G′ and G″ and consistency coefficient. Starch from the least mealy cultivar (Pukhraj) showed higher retrogradation, which increased progressively during storage at 4 °C for 120 h.     

Comparison of rheological properties of native and pregelatinized potato starches

Rheological properties of native potato starch (NPS) and pregelatinized potato starch (PPS) were investigated under steady and dynamic shear conditions at 20°C and 60°C. The consistency index, apparent viscosity, and yield stress values of PPS were much lower than those of NPS. The flow behavior of PPS is more temperaturedependent. Dynamic moduli (G′ and G″) and complex viscosity of PPS were much lower than those of NPS, while tan δ values of PPS were in the range of 2.30–3.50 (tan δ>1), indicating that PPS is more viscous than elastic. Rheological properties of NPS are strongly influenced by pregelatinization.     

A comparison between the physico-chemical properties of tuber and cereal starches

Biofilms based on waxy maize and cassava starches (cereal and tuber starch, respectively), plasticized with glycerol were characterized through their crystallinity, dynamic-mechanical behavior (DMA), thermal degradation (TGA), moisture content and water vapor permeability (WVP). X-ray diffraction experiments show that both materials were mainly amorphous, with the waxy starch presenting a discreetly A-type X-ray pattern. Microscopic investigation of the cryo-fractured surfaces supported this observation. The glass transition of the glycerol-rich phase (measured by DMA) occurs at higher temperatures for cassava than for waxy maize starch, suggesting that the dispersion level of glycerol is higher in the former. TGA showed that maize starch has a slightly higher thermal stability than cassava starch, while glycerol interacts more strongly with the last one. The WVP was 18% higher in the case of the cassava starch film.     

Relationship between physicochemical and rheological properties of starches from Indian wheat lines

Starches from nine Indian wheat lines were evaluated to study the relationships between physicochemical and rheological properties. Large granules (>15 μm) were present in the highest proportion followed by medium (5–15 μm) and small granules (<5 μm). Amylose content ranged between 27.4 and 37.2%. Starch with the highest proportion of large granules (68.9%) showed higher values of G′_peak (576 Pa) and G′_final (432 Pa). Amylose content showed positive relationships with retrogradation, gel firmness, gumminess and adhesiveness while negative with springiness. Cooked starch pastes with the highest amylose content (37.2%) had higher ΔH_ret (0.88 J g^?1), G′_ret (361 Pa), adhesiveness (1.48 Ns), firmness (0.45 N) gumminess (0.22 N) and the lowest springiness (0.88). Amylose–lipid complex (AML) dissociation showed negative relations with swelling power, G′_peak, G′_breakdown and breakdown viscosity (r = ?0.779, ?0.66, ?0.771 & ?0.775, respectively, P < 0.05) while positive relationship with pasting temperature (r = 0.775, P < 0.05).     

Microstructure and rheological properties of psyllium polysaccharide gel

The strong gelling property of psyllium polysaccharides is closely related to its health benefits and applications, such as use as a binding agent in the landscape industry. However, information about gelling properties of psyllium polysaccharides is very limited. To explore the gel properties of psyllium, the alkaline extracted gel fraction (AEG) of psyllium polysaccharides was studied in this investigation. The rheological and low-temperature electron microscopy methods including cryo-scanning electron microscopy (Cryo-SEM) and freeze-substitution for transmission electron microscopy (TEM) were used to investigate Ca²⁺ influence on the gel properties of AEG. AEG formed a weak gel with a fibrous appearance. AEG did not have a sharp melting point and exhibited no thermal hysteresis during heating and cooling procedure. The origin of this gelling behaviour was due to the fibrillar gel structure of psyllium polysaccharide. It was found that Ca²⁺ had a significant influence on the gel properties and microstructure. Elastic modulus G′ of gel increased as Ca²⁺ concentration increased. Critical strain S at first increased and then decreased as Ca²⁺ concentration increased. AEG gel became more resistant to temperature change on addition of Ca²⁺. Psyllium gel changed to aggregated gel with added Ca²⁺. The strands of gel appeared thicker and the density of the junction zone increased with increasing Ca²⁺ concentration as revealed by SEM and TEM. The changing bulk gelling properties of psyllium polysaccharide by adding Ca²⁺ was attributed to the change in gel structure.     

玉米淀粉和马铃薯淀粉共混糊化及凝胶特性的研究

本文研究了不同比例（100:0、75:25、50:50、25:70及0:100）玉米淀粉和马铃薯淀粉混合物的糊化及凝胶特性。结果表明,玉米淀粉的峰值黏度(3.07 Pa?s)、最终黏度(2.99 Pa?s)、稠度系数（11.31）及流体行为指数（0.39）均显著低于马铃薯淀粉（分别7.04 Pa?s、3.98 Pa?s、33.18和0.62）,而糊化温度（76.18℃）显著高于马铃薯淀粉（71.05 ℃）,混合物的相应值均介于2种纯淀粉之间,但并不呈线性关系,凝胶的破断力和水分子状态等参数也呈类似特征,表明2种淀粉在搅拌下加热糊化时发生了相互作用。静置状态下加热测得的凝胶化焓值呈累加效应。     

Temperature dependence of starch gel rheological properties

In an attempt to learn more about molecular mechanisms and thermodynamic preconditions of development of spatial structures of starch systems, the authors analyzed the kinetics of structuralization processes in the temperature function of the course of these processes. The method of dynamic-mechanical analysis (DMA) was employed in the performed investigations. On the basis of empirical values of G₁ and G₂, the energetic status of the gel network as well as changes in this status during the structuralization process was determined. In the state of complete hydration, the retrogradation mechanism of the examined starch systems consisted in the bundle–coil transition. This transition required a decline in the temperature of the system below temperature θ determined by the ratio of the enthalpy to entropy transition: ΔH/ΔS ≈ 322 K ≈ 49 °C. This transition is a cooperative transformation of two fragments of neighboring chains in a condition of chaotic confrontation to a state of bihelical associated molecules. The bihelical association of starch chains is the main source of stabilization of the spatial structure of starch hydrogels below the θ transition temperature.     

Functional and dynamic rheological properties of acetylated starches from two cultivars of cassava

The starches derived from two different cultivars of cassava were modified with acetic anhydride. The increase in swelling power and solubility of the cassava starch (CS) pastes treated with different acetic anhydride concentration could be attributed to easier hydration, resulting from reduction of interaction between starch chains due to the substitution. The transition temperatures (T_o, T_p and T_c) and enthalpy of gelatinisation (ΔH) of acetylated CS, were determined. The values were lower than those of native starches. Rheological properties of CS pastes (5% w/w) as a function of the degree of substitution were evaluated in dynamic shear force measurements. Magnitude of storage modulus (G′), loss modulus (G′′) and complex viscosity (Eta*) of acetylated CS pastes were determined also. Dynamic moduli (G′, G′′ and Eta*) values of acetylated sweet cultivar pastes were generally higher than those of native starch whereas the acetylated samples of the bitter cultivar were lower than those of native starch. The magnitudes of G′ were greater than those of G′′ and Eta* at all frequencies (ω). The fact that all the tan δ (ratio G′′/G′) values (0.7–0.48 and 0.25–0.44) were less than one is an indication that the samples are more elastic than viscous. The acetylated starches could find promising industrial uses in food products like Lemon curd and Mayonnaise and other non‐food applications.