冻融处理对淀粉颗粒结构和性质影响的研究进展

淀粉是一种重要的食品工业原料,淀粉颗粒的形状,大小,直支链比例和晶型结构是决定淀粉功能的重要因素。针对淀粉在加工生产中因冻融而引起的变化,对淀粉冻融理论进行了阐述;讨论了冻融处理对淀粉理化性质如颗粒形态、结晶度、热力学和生物学性质的影响;分析了淀粉颗粒冻融特性的影响因素,为进一步研究冻融处理对淀粉的影响提供参考。     

四种常用淀粉物理性质的比较研究

主要研究了四种常用淀粉(玉米淀粉、马铃薯淀粉、木薯淀粉、小麦淀粉)的透明度、冻融稳定性、凝沉性、膨胀度及糊化特性，并进行比较。为进一步了解这四种淀粉的特性及应用，提供了理论依据。     

改性淀粉基可食性膜的制备及性能研究

以改性淀粉为成膜基材,采用溶液流延法制备可食性膜.研究了改性淀粉种类及浓度、增塑剂种类、甘油添加量、增强剂种类、普鲁兰多糖添加量对膜性能的影响.结果表明,采用羟丙基交联淀粉为基材,淀粉浓度为5 g/100 mL,增塑剂甘油添加的质量分数为30％,增强剂普鲁兰多糖添加的质量分数为淀粉质量的10％,制备的淀粉膜综合性能较好...     

氯化钠对玉米淀粉冻融稳定性的影响

对NaCl对玉米淀粉冻融稳定性的影响进行了研究。采用差示扫描量热仪(DSC)、扫描电子显微镜(SEM)和质构仪(TPA)等现代分析仪器分别研究不同摩尔浓度的NaCl对淀粉糊凝胶冻融析水率、超微结构、回生热力学特性以及质构的影响,并通过zeta电位分析仪探讨了盐离子与淀粉分子间的相互作用。结果表明:NaCl可降低玉米淀粉的析水率,减小淀粉凝胶结构的破裂;经过5次冻融后的玉米淀粉凝胶硬度和回生率均与NaCl溶液浓度呈显著负相关;NaCl的添加使得体系zeta电位下降,证明Na+与淀粉分子间存在相互作用,进而抑制冻融过程中淀粉的回生。     

单甘酯对小麦淀粉凝胶冻融稳定性的影响

为了提高小麦淀粉凝胶的冻融稳定性,研究了单硬脂酸甘油酯对小麦淀粉凝胶晶体结构、热力学特性及质构特性的影响。结果表明,X-射线衍射图显示样品中含有V-型结晶结构,说明单甘酯与淀粉结合形成了淀粉-单甘酯复合物;差示扫描量热仪测定显示,淀粉凝胶样品含有直链淀粉重结晶的熔融峰和淀粉-单甘酯复合物的熔融峰,复合物熔融焓显著小于淀粉凝胶熔融焓;经过5次冻融循环,小麦淀粉凝胶中淀粉分子发生了重结晶,淀粉凝胶的结晶度从15.37%增大至18.75%,而添加单甘酯形成复合物的淀粉凝胶结晶度从13.98%增大至17.35%;随着冻融循环增加,小麦淀粉凝胶中支链淀粉重结晶的熔融焓增加显著大于含复合物淀粉凝胶中支链淀粉重结晶的熔融焓增加,并且小麦淀粉凝胶硬度显著大于含复合物淀粉凝胶硬度。说明单甘酯与淀粉形成复合物能提高小麦淀粉凝胶的冻融稳定性。     

微波处理对可食性壳聚糖/淀粉复合膜性能的影响

以壳聚糖和淀粉为主要原料制备了可食性复合膜,考察了不同微波处理功率、处理时间对可食性复合膜性能的影响。在固定的处理时间范围内,升高微波功率,复合膜的抗张强度显著增加,断裂伸长率降低。对于固定的微波功率,膜的抗张强度随处理时间的延长而提高,但微波处理时间在30s以上时,膜表面产生气泡;处理时间在25s时,膜的外观和抗拉强度理想。     

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。     

多糖胶对木薯淀粉糊冻融稳定性影响

为揭示多糖胶与淀粉之间产生协同作用机理,采用Branbender粘度计和扫描电子显微镜探讨四种多糖胶对木薯淀粉糊性质影响.结果表明,瓜尔胶使木薯淀粉糊起始糊化温度降低,而峰值粘度、崩解值和回生值及终值粘度都有显著提高;海藻酸钠对木薯淀粉糊峰值粘度和崩解值有明显提高,并在一定程度上降低糊的起始糊化温度;魔芋胶和阿拉伯胶使...     

淀粉冻融稳定性的研究进展

淀粉的冻融稳定性直接影响速冻面食的品质。综述了冻融处理对淀粉理化性质和结构特征的变化及冻融稳定性的主要影响因素,对可能的作用机理进行了分析和探讨。为速冻面食的工业生产和品质优化提供了一定的理论参考。     

亚麻籽胶对糯米淀粉凝胶冻融稳定性影响

为了解亚麻籽胶对糯米淀粉凝胶冻融稳定性的影响,利用差示扫描量热仪、X-射线衍射、傅里叶变换红外光谱仪和扫描电镜测定添加不同比例亚麻籽胶的糯米淀粉凝胶经过7次冻融循环后的热力学特性、结晶性、分子结构和微观结构。结果显示,亚麻籽胶能显著降低糯米淀粉凝胶的析水率;淀粉凝胶熔融焓/糊化焓降低显示糯米淀粉凝胶老化受抑制;随着亚麻籽胶添加量增大糯米淀粉凝胶相对结晶度降低,显示亚麻籽胶抑制了淀粉凝胶的重结晶;亚麻籽胶使淀粉凝胶羟基伸缩振动峰发生较大的位移,增强分子间氢键作用力,而没有生成新的基团;添加亚麻籽胶的淀粉凝胶微观结构表面光滑平整,凹洞较小,基质较紧密。说明亚麻籽胶能提高糯米淀粉凝胶的冻融稳定性。     

Mechanical Properties, Water Vapor Permeabilities and Solubilities of Highly Carboxymethylated Starch-Based Edible Films

ABSTRACT: Tensile strength (TS), elongation (E), water vapor permeabilities (WVP) and solubilities were determined for highly carboxymethylated starch (HCMS)-based edible films plasticized with sorbitol (S), xylitol (X), mannitol (M) and glycerol (G). TS and E of HCMS-based film increased as the concentration of plasticizer S, M or × increased. TS of the HCMS-based film containing combined plasticizers were higher than those of films containing single plasticizer. The WVP of HCMS-based films seemed to decreased as the concentration of M, X or G plasticizer increased. Increasing plasticizer concentrations in HCMS-based film resulted in decreasing solubility of the films.     

Effects of pH and Salts on Physical and Mechanical Properties of Pea Starch Films

To identify the significant contribution of intermolecular hydrogen bonds of starch molecules to the film structure formation, pH of film‐forming solutions was adjusted and also various salts (NaCl, CaCl₂, CaSO₄, and K₂SO₄) were mixed into the glycerol‐plasticized pea starch film. The film made from pH 7 possessed the highest tensile strength‐at‐break (2 times) and elastic modulus (4 to 15 times) and the lowest elongation‐at‐break compared with those of the films made from acid and alkali environments. The pH 7 film also has the highest film density and the lowest total soluble matter. At the level of 0.01 to 0.1 M of CaSO₄ and 0.1 M of K₂SO₄ in a kilogram of starch, the water solubility of the film increased, while chloride salts slightly lowered the solubility. NaCl and CaSO₄ reduced water vapor permeability (WVP), while CaCl₂ slightly increased WVP at 0.01 and 0.06 M concentrations, and K₂SO₄ significantly increased WVP at 0.03 and 0.15 M. Presence of salts increased tensile strength (5 to 14 times than the control films) and elastic modulus (35 to 180 times) of starch film at 0.01 to 0.03 M of CaSO₄ and K₂SO₄. Elongation‐at‐break increased significantly as salt concentration increases to an optimal level. However, when the concentration exceeded above the optimal level, the E of starch films decreased and showed no significant difference from the control film. Overall, the addition of salts modified physical and mechanical properties of pea starch films more than pH adjustment without any salt addition.     

Physical and Mechanical Properties of High-amylose Rice and Pea Starch Films as Affected by Relative Humidity and Plasticizer

ABSTRACT: The tensile properties, water vapor permeability, oxygen permeability at different relative humidities (RH), and water solubility of edible films made of high-amylose rice starch (RS) or pea starch (PS) were measured and compared with the most commonly used edible films. Photomicrography of starch films shows amylopectin-rich gels and amylose-rich granules. The addition of glycerol into starch films made amylose-rich granules swollen and continuously dispersed between amylopectin-rich gels. Tensile strength of RS and PS films decreased when RH increased from 51% to 90%, whereas elongation-at-break (E) of both films increased when RH increased. Water vapor permeabilities of both films were similar, resulting in 130 to 150 g mm/m²/d /kPa. Oxygen permeability of RS and PS were very low (< 0.5 cm³μm/m²/d/kPa) below 40% RH, and 1.2 to 1.4 at 45% RH. Water solubility of PS film was 32.0%, which is lower than that of RS film (44.4%). Overall high-amylose rice and pea starch films possess an excellent oxygen barrier property with extremely high stretchability.     

壳聚糖/微晶甾醇可食性复合膜的制备、性能及结构表征

以壳聚糖为成膜基质,添加具有抗氧化和抑菌作用的植物甾醇,采用流延法制备壳聚糖/微晶甾醇可食性复合膜,旨在赋予壳聚糖膜抗氧化活性及提高其抑菌性。当甾醇添加量分别为壳聚糖质量的0%~12%时,随着添加比例的增加,复合膜的拉伸强度和断裂伸长率逐渐下降,溶解度和溶胀度逐渐增加,水蒸气透过系数显著降低,对超氧阴离子自由基(O_2~-·)及羟自由基(·OH)的清除率显著提高,对金黄色葡萄球菌和大肠杆菌的抑菌性能明显增强;采用红外光谱、扫描电子显微镜、X射线衍射和热重分析表征了复合膜的相容性。结果表明:甾醇添加量为9%的壳聚糖/微晶甾醇可食性复合膜各项性能指标良好,且壳聚糖与甾醇分子之间形成了分子间氢键,有较强的相互作用,整个共混体系的相容性良好。     

Physical and Mechanical Properties of Pea Starch Edible Films Containing Beeswax Emulsions

ABSTRACT:  Hydrophobic beeswax emulsions were incorporated into hydrophilic starch films to modify physical, mechanical, and thermal properties of the films. Beeswax was added in the film-forming solution of high-amylose pea starch (35% to 40% amylose w/w) at the level of 0%, 10%, 20%, 30%, and 40% w/w of starch with glycerol as a plasticizer (40/60 of glycerol/starch). Addition of beeswax affected mechanical properties, significantly reducing tensile strength and elongation and increasing elastic modulus. Beeswax addition decreased water vapor permeability and increased oxygen permeability. However, the addition of hydrophobic wax particles in starch films marginally affected these physical properties below 30% beeswax in the films. Beeswax addition at the 40% concentration formed amylose–lipid complex that caused the dramatic changes of physical and thermal properties of the films.     

热处理对大豆分离蛋白可食性膜性能和结构的影响

研究热处理对大豆分离蛋白膜性能和结构的影响,90℃热处理后制得的大豆分离蛋白膜呈现出最佳机械性能和阻隔性能。同时研究热处理后蛋白的结构变化,包括二硫键数量、疏水值和二级结构。结果显示：二硫键和α- 螺旋含量与膜机械和阻隔性能呈现正相关性,而疏水值与膜机械和阻隔性能呈现负相关性。     

Physical and Mechanical Properties of Pea-Protein-based Edible Films

ABSTRACT: Edible films produced from denatured pea protein concentrate (PPC) solution possessed the strength and elasticity to resist handling. Increasing the concentration of the plasticizer (glycerol) in the film decreased tensile strength and elastic modulus, and increased elongation and water vapor permeability (WVP). Very strong and stretch-able films were obtained from 70/30 and 60/40 of PPC/glycerol composition, respectively. The low WVP value was maintained over a range of glycerol concentration from 20% to 40%, in the dry film. Film solubility was not affected significantly by the amount of the plasticizer. The physical and mechanical properties of the PPC films were comparable with those of soy protein and whey protein films.     

增塑剂甘油对甘薯淀粉膜性能的影响研究

采用甘油作为增塑剂制备甘薯淀粉膜,研究了甘油/淀粉比对甘薯淀粉膜性能的影响。结果表明:加入甘油后,淀粉糊各特征点黏度值发生不同程度的变化;随着甘油量的增加,膜的断裂伸长率和水蒸气透过率呈递增的趋势,淀粉膜的热封性能逐步得到提高,抗拉强度呈递减的趋势;随着甘油的加入,膜的透光率增大;甘油分子与淀粉分子之间有较弱的作用,在2θ=14.8°处产生了一个新的峰;淀粉颗粒的分散和分布随着甘油的加入有明显改善,淀粉膜表面变得平整;紫外老化试验表明随着甘油量的增加,延缓了淀粉膜的老化作用。当甘油/淀粉比在0.3/1~0.4/1之间时,甘油和淀粉的相容性较好,甘油对淀粉有较好的塑化效果。     

Mechanical and Thermal Characteristics of Pea Starch Films Plasticized with Monosaccharides and Polyols

Edible starch films were produced from pea starch and various plasticizers (mannose, glucose, fructose, and glycerol and sorbitol) at the ratio of 4.34, 6.50, 8.69, and 10.87 mmol plasticizer per gram of starch. After film specimens were conditioned at 50% relative humidity, mechanical properties (tensile strength, elongation, and modulus of elasticity), water vapor permeability (WVP), moisture content, and thermomechanical properties (G’ and tan8) were determined as a function of plasticizer concentration. At all concentration levels, monosaccharides (mannose, glucose, and fructose) made the starch films stronger (higher tensile strength) and more stretchable than polyols (glycerol and sorbitol), while WVP of monosaccharide‐plasticized starch films were lower than those of polyol‐plasticized starch films, especially at higher plasticizer concentration levels. Except for 4.34 mmol/g of mannose‐plasticized film, all the other films showed similar modulus of elasticity at the same plasticizer concentration. Polyol‐plasticized films had lower T than the monosaccharide‐plasticized films. Glucose‐ and sorbitol‐plasticized films needed more activation energy to go through glass transition than others. After all, research results showed that not only the polyols but also the monosaccharides were effective in plasticizing starch films. It is concluded that molecular size, configuration, total number of functional hydroxyl group of the plasticizer as well as its compatibility of the plasticizers with the polymer could affect the interactions between the plasticizers and starch molecules, and consequently the effectiveness of plasticization.