Enzymatic modifications of pea protein and its application in protein-cassava and corn starch gels

The interactions between starch and proteins during processing influence pasting and rheological properties of starch and produce modifications on starch gel structure. Enzymatic modifications have been proposed for overcoming the limitations of using proteins as food ingredients. This work aimed to study the impact of native and enzymatically modified pea proteins on the properties of protein-starch (from cassava or corn) gels. Pea protein isolate (PPI) was incubated with endopeptidase (AL) or microbial transglutaminase (TG). Pasting profile, rheological behaviour and water retention capacity of protein-starch gels were analyzed. Protein (native and enzymatically modified) incorporation increased the viscosity of both corn and cassava starches during gel preparation. However, the hydrolyzed protein reduced drastically the increment of viscosity of protein-starch gels. The addition of PPI led to corn starch network that shifted from an elastic-like nature to a more viscous-like, whereas the opposite effect was observed in cassava gel network. TG- and AL-treated proteins led to a decrease of both G′ and G″ moduli of protein-starch gels, and AL-treated proteins showed the highest decrease on these parameters. Hydrolyzed proteins also favoured the syneresis of the protein-corn starch gel, whereas crosslinked proteins tended to reduce it. Enzymatic modifications of pea proteins affected significantly pasting and rheological properties of protein-starch gels.     

Supramolecular structure of A- and B-type granules of wheat starch

The supramolecular structure of the A- and B-type granules of wheat starch was compared. Polarized light microscopy, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) were used to study the granular, crystalline, and short-range structures. The A- and B-type granules displayed a typical A-type crystalline structure with the degrees of crystallinity of 31.95% and 29.38% respectively. In addition, the B-type granules had some V-type crystallites. The nanostructure and fractals were characterized by small angle X-ray scattering (SAXS), which showed that the average thickness of the lamellae of the A-type granules was larger, while the B-type granules possessed a higher degree of ordering in the lamellar regions. A second order reflection was found in both A- and B-type granules, which was proposed due to the crystalline lamellae of the semicrystalline lamellae. The A- and B-type granules had mass and surface fractal structures respectively.     

冷冻条件下绿豆抗老化的应用技术研究

为了抑制绿豆在冷冻条件下老化变硬而导致的口感品质下降,本课题以新鲜绿豆为原料,经过纤维素酶酶解处理,通过正交试验,研究了不同酶解条件对绿豆抗老化性质的影响。结果表明,用纤维素酶处理绿豆粒,将组成绿豆细胞壁的纤维素骨架逐级降解,进而破坏细胞壁的骨架结构,有利于糖分子渗入到绿豆内部,从而延缓分子链的迁移速率,降低淀粉回生速率。在pH5、酶解温度50℃,添加0.1%的纤维素酶,酶解80min时得到的绿豆粒,经过50%蔗糖溶液煮制1h后,绿豆粒抗老化能力最强,其口感风味最佳。     

高交联木薯淀粉非糊化特征研究

研究了以三偏磷酸钠为交联剂制备非糊化的高交联木薯淀粉的方法,测定了反应的取代度和布拉班德粘度曲线,提出高交联木薯淀粉与原淀粉颗粒不同,在沸水中只发生轻微溶胀,呈非糊化颗粒态。     

湿热处理法制备慢消化淀粉及其性质研究

以蜡质玉米淀粉为原料,采用湿热处理法制备慢消化淀粉,并研究了其性质。研究出湿热处理制备慢消化淀粉的优化工艺为:淀粉体系的水分含量35%(w/w),温度120℃,时间为10h,慢消化淀粉含量达9.25%。扫描电镜照片显示,湿热处理后淀粉颗粒表面出现了裂纹和凹坑,淀粉糊化温度升高,峰值粘度降低。     

The effect of concentration and botanical source on the gelation and retrogradation of starch

The changes in shear modulus of pea, wheat, maize and potato starch gels with time, at concentrations between 10 and 40% w/w, were followed. In this range, the cooling of gelatinised dispersions of starch resulted in turbid, elastic gels. The initial rate of development of stiffness of the gels followed the order: pea>maize>wheat>potato, and was related to the amount of amylose solubilised during gelatinisation. The initial gelation was not reversed on heating to 100° C. There was also a long-term increase in gel stiffness, which was thermally reversible. This long-term increase, linked to a crystallisation involving amylopectin, followed the order: pea>potato>maize>wheat. With increasing starch concentration this latter process becomes more important.     

大米多孔淀粉及大米多孔酯化淀粉吸附特性的研究

研究大米多孔淀粉和大米多孔酯化淀粉对次甲基蓝的吸附特性,分析酶解时间和取代度对淀粉吸附次甲基蓝的影响,在此基础上建立了大米多孔淀粉和大米多孔酯化淀粉的吸附速率方程。结果表明,大米多孔淀粉吸附次甲基蓝的最佳浓度为25×10-5mol/L,大米多孔淀粉和大米多孔酯化淀粉对次甲基蓝的饱和吸附量分别为4.88mg/g和5.97mg/g。与大米原淀粉相比,大米多孔淀粉和大米多孔酯化淀粉对次甲基蓝的吸附量得到明显提升,其中大米多孔酯化淀粉的吸附量更大。     

Thermal, microstructural and textural characterisation of gelatinised corn, cassava and yam starch blends

The functional properties of mixtures of maize, cassava and yam starches and their relationships with microstructural characteristics were investigated. Experiments were performed following the simplex‐centroid design with internal points and restrictions (upper limit) for yam starch proportion. The statistical model used (Scheffé canonical equation) was a powerful tool to predict the pastes behaviour within the limits of the experimental area. Polynomials with second level interactions were applied to obtain the surface response. Viscoelastic attributes of mixtures differed from those of individual starches. As shown by differential scanning calorimetry and microscopical observations, physical properties of the mixtures depended on the type of networks obtained. These networks varied upon yam, corn and cassava starch proportions as each one has a particular characteristic: gelatinisation temperature, granule size, swelling capacity and amylose/amylopectin ratio among others.     

糖化酶法制备微孔淀粉工艺条件的研究

采用糖化酶对玉米淀粉进行部分降解制备微孔淀粉，通过对淀粉得率、比容积和吸油率的考察和扫描电镜观察，研究微孔淀粉质量随不同酶浓度和处理时间的变化规律，并采用正交实验方法优化温度、pH和钙离子浓度等微孔淀粉制备的工艺条件。     

凝固剂及凝固条件对大豆蛋白胶凝性质的影响

以大豆蛋白的凝胶强度、持水性、凝固速率这3个胶凝特性为主要指标,测定了包括蛋白浓度、热处理温度和时间、凝固剂种类和添加量、pH值、离子强度在内的这些因素对上述胶凝性质的影响,并确定了最优凝固工艺条件:质量浓度60g/L的SPI溶液经95℃热处理15min后,分别以质量分数0.4%熟石膏(CaSO4·1/2H2O)和质量分数0.28%葡萄糖酸内酯(GDL)作为凝固剂,保温30min后,冷却至室温;最佳离子强度为0.01mol/L(NaCl)。     

玉米淀粉颗粒冻融特性影响因素及机制研究进展

玉米淀粉是一种供应稳定、价格低廉,广泛应用于焙烤食品、医药及食品工业等领域的重要原材料。综述了玉米淀粉变性方法现状,详细分析了玉米淀粉颗粒冻融特性的影响因素,探讨了玉米淀粉颗粒冻融变性机制,玉米淀粉颗粒冻融变性机制可能是冰晶微机械破坏力和水分迁移渗透压力共同作用的结果。     

颗粒冷水可溶淀粉制备技术研究

研究了采用乙醇-碱溶液处理方法制备颗粒冷水可溶淀粉的工艺技术。以溶解度和粘度作为评价指标，通过正交试验和响应面分析，得出制备颗粒冷水可溶淀粉的工艺中反应温度与乙醇浓度对溶解度影响显著，反应温度、碱用量、乙醇浓度及反应温度与碱用量、碱用量与乙醇用量的交互作用对粘度影响显著。     

Microstructures of starch granule,starch digestibilities and predicted glycaemic index of common bean mutants in Taiwan

In this study, the microstructure of starch granule and in vitro starch digestibility were compared in de‐coated seeds of common bean variety Hwachia and its NaN₃‐induced mutants. Significant differences in starch granule size (between 17.92 and 27.00 μm), total starch content (between 436.5 and 456.8 mg per seed) and resistant starch content (between 51.6 and 203.3 mg per seed) were found among mutants. Both boiling and autoclaving decreased resistant starch content in processed common beans. Significant difference in predicted gylcaemic index (pGI) (between 48.82 and 64.55%) for processed beans also existed among mutants. However, 96 h of 4 °C storage increased resistant starch content in processed common beans, possibly resulted from starch retrogradation during storage. Mutants SA‐05, SA‐08 and SA‐31, which have smaller seed weight and lower pGI (average of 50.08%) compared to Hwachia (pGI of 57.05%), can be used to produce common bean based low GI dietary carbohydrate.     

淀粉颗粒结构体系

该文就淀粉分子、微晶和淀粉颗粒结构组成及其相互间关系进行论述。由支链淀粉分子形成无定形层和结晶层构成微晶,当低分支或链长较短分子存在于微晶时会形成缺陷微晶,常态微晶组成淀粉颗粒中硬质骨架,而缺陷微晶组成软质骨架,微晶还原端朝向颗粒脐点;依据常态微晶和缺陷微晶排列,淀粉颗粒分为同型骨架和异型骨架两种类型。     

Processing of mungbean products and its nutritional and organoleptic evaluation

Four mungbean products namely, whole fried namkeen, dehusked fried namkeen, roasted namkeen and salad were formulated using three different cultivars of mungbean viz. UPM 98‐1, Pant Mung‐5 and Pant Mung‐2 and the effect of different processing methods on texture and nutrient composition were studied. All the products were found to be acceptable by the panel. Salad was found to be the most acceptable product with overall acceptability of 8.31 out of 10 followed by dehusked fried namkeen (7.80), whole fried namkeen (7.61) and roasted namkeen (7.02). Moisture and protein content increased significantly after germination for 24 h. Fat content increased significantly for deep fried products. Total ash, crude fibre and mineral content decreased significantly after processing whereas in‐vitro iron bioavailability and in‐vitro protein digestibility increased significantly after processing. Texture analysis revealed that dehusked fried namkeen of Pant Mung‐5 and roasted namkeen of Pant Mung‐2 had maximum crispness and hardness, respectively, which are preferred attributes.     

绿豆分离蛋白的制备及其功能特性的研究

研究了绿豆蛋白浸提的最佳工艺参数及其功能特性,结果表明,绿豆蛋白浸提的最佳工艺条件是:pH值9.0、提取温度40 ℃、提取时间20 min、料水比1∶15;绿豆分离蛋白的起泡性和泡沫稳定性较好,且具有一定保水性、乳化性及乳化稳定性,但吸油性较差.     

机械活化预处理对木薯淀粉氧化产物理化性质的影响

研究机械活化预处理对木薯淀粉氧化产物理化性质的影响。采用搅拌球磨机对木薯淀粉进行机械活化,以不同活化时间的木薯淀粉为原料,CuSO4为催化剂,H2O2为氧化剂干法制备氧化淀粉,对由不同活化时间木薯淀粉制备的氧化淀粉的溶解度、表观黏度、透明度、冻融稳定性、凝沉性等性质进行研究。试验结果表明：机械活化预处理对木薯淀粉氧化产物的理化性质产生显著的影响,随着机械活化时间的延长,氧化淀粉的溶解度、透明度增大,表观黏度降低,冻融稳定性减弱,凝沉性增强。     

葛根淀粉理化性质的研究

葛根淀粉特有的保健特性使其成为近年来国内外走俏的淀粉产品。系统地研究了葛根淀粉的颗粒、糊等方面的性质,结果表明,其颗粒较小,粒径平均值为12.2mm,结晶结构为C型,直链淀粉含量为19.8%,糊化温度范围为57.5~64.7℃。葛根淀粉凝沉性比玉米淀粉弱,冷糊粘度稳定性较好,其他性质与玉米淀粉比较相似。     

非晶颗粒态玉米淀粉制备方法

系统地报道了水分散体系高温溶胀、常温碱分散体系强碱溶胀作用非晶颗粒态玉米淀粉制备方法,采用偏光显微镜对多晶态向非晶态的变化进行了确认,提出在一定条件下,高交联玉米淀粉可以由原淀粉多晶颗粒态制备成只含无定形结构的非晶颗粒态淀粉。     

淀粉糊化及其检测方法

淀粉糊在食品工业具有重要应用价值,淀粉糊性质直接影响食品品质。该文介绍淀粉糊化特性及其检测方法,详述各种检测方法在淀粉糊中应用实例,并指出其中优缺点;提出今后淀粉糊检测方法发展方向,为淀粉糊在食品工业广泛应用奠定基础。