酸解压热法制备玉米抗性淀粉

以玉米淀粉为原料,经盐酸水解后进行压热处理,制备玉米抗性淀粉,并确定了最佳工艺条件:淀粉糊浓度为35%、热处理时间1.5h、酸用量1.25%、酸解时间2h,抗性淀粉最高得率为22.88%.     

甘薯抗性淀粉理化性质研究

采用酶法结合超声波处理制备抗性淀粉,并分析其颗粒分布、晶体结构类型、淀粉分子结构、热特性等理化特性 结果表明,甘薯抗性淀粉颗粒分布、粒径大小、晶体结构、熔融温度明显不同于甘薯淀粉.甘薯抗性淀粉平均粒径、糊化峰值温度、终止温度大于甘薯淀粉;甘薯淀粉结晶结构表现为C型,甘薯抗性淀粉结晶结构表现为B型,酶解辅以超声波处理的方法可以制备高含量的抗性淀粉.     

板栗苞中栲胶提取工艺的研究

目的以板栗苞为原料,研究板栗苞提取栲胶的最佳工艺。方法在粉碎粒度、丙酮溶液浓度、料液比和超声功率单因素实验基础上,以栲胶提取率为响应值,设计4因素3水平的均匀实验,通过均匀设计偏最小二乘回归建模分析,得出最优指标时各个因素组合参数,并采用铬皮粉法对最优条件下提取的栲胶进行分析。结果板栗苞中栲胶提取的最佳工艺为:粉碎粒度100目,50%丙酮溶液,料液比1:18,超声功率400 W,在此条件下,栲胶提取率为31.28%,单宁含量为63.68%,p H值为3.81,总色值为22。结论以板栗苞为原料提取的栲胶达到了橡椀栲胶冷溶合格品的指标,说明板栗苞提取栲胶的工艺可行性。     

Structural and physicochemical properties of banana resistant starch from four cultivars

Resistant starches were isolated from four banana cultivars: Musa AAA Cavendish, Musa ABB Bluggoe, Musa ABB Pisan Awak, and Musa AA Pisang mas. The structural and physicochemical properties of banana resistant starches were studied. Results showed that the particle size and shape of four banana resistant starches were different. Cavendish and Bluggoe banana resistant starch had a C-type crystalline structure, whereas Pisan Awak and Pisang mas had a B-type. The water-holding capacity of Pisang mas was the maximum. The solubility of Pisan Awak and Pisang mas was higher as compared to Cavendish and Bluggoe. The transparency of Cavendish banana resistant starch was the highest. More amylose was observed in Bluggoe and Pisan Awak banana resistant starch, whereas more amylopectin was observed in Cavendish and Pisang mas banana resistant starch. The initial pasting temperatures of Cavendish and Bluggoe banana resistant starches were higher as compared to Pisan Awak and Pisang mas banana resistant starch. The peak viscosity of Cavendish banana resistant starch was the highest in these four samples. The heat stability of Bluggoe banana resistant starch was the best one in the four banana resistant starches. The retrogradation was hard in the case of Bluggoe and Pisan Awak banana resistant starch. In conclusion, the properties of the four banana resistant starch samples were not the same, indicating that these could be used in different food products.     

普鲁兰酶酶法制备玉米抗性淀粉工艺优化

以普通玉米淀粉为试验材料,采用响应面法优化普鲁兰酶酶法制备玉米抗性淀粉的工艺参数。结果表明,普鲁兰酶加量、酶解时间、老化温度以及老化时间对抗性淀粉含量均有显著影响,所建回归模型高度显著,充分反映抗性淀粉含量与各因子之间的关系。优化工艺参数为普鲁兰酶加量20 U/g,酶解时间24 h,酶解物在4℃条件下存放老化36 h,样品抗性淀粉质量分数为9.75%,相比原淀粉增幅达89.4%。电镜扫描结果显示普鲁兰酶酶法制备的玉米抗性淀粉颗粒形貌呈不规则形状,原淀粉颗粒结构形态被破坏。     

酶法制备抗性淀粉新工艺的研究

以普通玉米淀粉为原料,采用121℃20min压热--℃24h冷却的循环处理和酶解处理相结合的方法制备抗性淀粉,对压热-冷却循环次数和普鲁兰酶的添加顺序及酶作用时间进行研究.结果表明,在选定的酶用量(30U·mL-1)和酶作用温度(60℃)条件下,压热一冷却循环结合酶水解法,即糊化或老化1次后添加普鲁兰酶,可以显著提高普通玉米淀粉制备抗性淀粉的得率.并且老化1次后加入普鲁兰酶的作用效果更好.     

Isolation, fractionation and characterization of melanin-like pigments from chestnut (Castanea mollissima) shells

Melanins are known as versatile biopolymers, but the utilizations are restricted by their poor solubilities. Therefore, well soluble ones or their analogs are much desired. In this article, a new procedure was developed for fractionation of the pigments isolated from chestnut (Castanea mollissima) shells, and 3 fractions (Fr. 1, Fr. 2, and Fr. 3) were obtained. The solubilities of all the fractions in waters of different pH and in common organic solvents were studied. The physicochemical properties of the fractions were characterized for the first time on the basis of combined chemical analyses and spectroscopic methods including ultraviolet-visible (UV-Vis), Fourier transform infrared (FT-IR), electron spin resonance (ESR), and solid-state (13)C nuclear magnetic resonance ((13)C-NMR). All the fractions could be bleached by NaOCl and H(2)O(2) and give a positive reaction for polyphenols, which are usually used as typical tests for allomelanins. Their UV-Vis, FT-IR, and ESR spectra resembled those of synthetic and some natural melanins. Elemental data and quantitative analyses of (13)C-NMR spectra revealed that pigment-bound proteins and polysaccharides were the most abundant in Fr. 1, while Fr. 2 was presented with the highest aromaticity. PRACTICAL APPLICATION: We provided a new, simple, and inexpensive method to fractionate the melanin-like pigments from chestnut shells. This technique can be used to produce natural melanin-like food colorants with different solubilities from chestnut shells.     

水杨酸处理对板栗冷藏品质及呼吸强度的影响

为探索水杨酸(SA)处理对板栗贮藏品质的影响,以镇安红栗为实验材料,采用不同浓度(10、50、100μmol.L-1)水杨酸水浴处理3d,于0±1℃条件下贮藏,对板栗贮藏过程中的腐烂率、呼吸强度、水分含量、淀粉、可溶性糖、可溶性蛋白质和VC含量变化进行研究。结果表明,SA水浴处理可以极显著降低板栗在贮藏中的腐烂率。10、50μmol.L-1的SA水浴处理能降低板栗贮藏后期呼吸强度,较好保持板栗在贮藏期间的水分、可溶性糖和VC的含量,降低淀粉的降解速率;10μmol.L-1的SA较好保持了可溶性蛋白质含量。因此,10μmol.L-1和50μmol.L-1的SA可以在一定程度上延缓板栗品质的下降。     

Production and physicochemical properties of resistant starch from hydrolysed wrinkled pea starch

The content and physicochemical properties of resistant starches (RS) from wrinkled pea starch obtained by different molecular mass reduction processes were evaluated. Native and gelatinised starches were submitted to acid hydrolysis (2 m HCl for 2.5 h) or enzymic hydrolysis (pullulanase, 40 U g^?1 for 10 h), followed by hydrothermal treatment (autoclaving at 121 °C for 30 min), refrigeration (4 °C for 24 h) and lyophilisation. Native starch showed RS and total dietary fibre contents of 39.8% and 14.3%, respectively, while processed ones showed values from 38.5% to 54.6% and from 22.9% to 37.1%, respectively. From these, the highest contents were among acid‐modified starches. Processed starches showed endotherms between 144 and 166 °C, owing to the amylose retrogradation. Native and processed starches showed low viscosity, which is inversely proportional to the RS concentration in samples. The heat treatment promoted an increase in the water absorption index. The pea starch is a good source for obtaining resistant starch by acid hydrolysis.     

Structural and physicochemical characterization of RS prepared using hydrolysis and heat treatments of chickpea starch

The aim of this study was to evaluate the production and the structural and physicochemical properties of RS obtained by molecular mass reduction (enzyme or acid) and hydrothermal treatment of chickpea starch. Native and gelatinized starch were submitted to acid (2 M HCl for 2.5 h) or enzymatic hydrolysis (pullulanase, 40 U/g per 10 h), autoclaved (121°C/30 min), stored under refrigeration (4°C/24 h), and lyophilized. The hydrolysis of starch increased the RS content from 16% to values between 20 and 32%, and the enzymatic treatment of the gelatinized starch was the most efficient. RS showed an increase in water absorption and water solubility indexes due to hydrolytic and thermal process. The processes for obtaining RS changed the crystallinity pattern from C to B. Hydrolysis treatments caused an increase in relative crystallinity due to the greater retrogradation caused by the reduction in MW. RS obtained from hydrolysis showed a reduction in viscosity, indicating the rupture of molecules. The viscosity seemed to be inversely proportional to the RS content in the sample.     

Physicochemical,thermal, and pasting properties of Chinese chestnut (Castanea mollissima Bl.) starches as affected by different drying methods

Starches from raw Chinese chestnut (Castanea mollissima Bl.) were isolated and dried by freeze drying and oven drying methods and the physicochemical, thermal, and the pasting properties were evaluated. Results showed that the two drying methods clearly affected the properties of the Chinese chestnut starches (CCS), both in composition, physicochemical, thermal, pasting properties, and functional characteristics. Freeze dried CCS presented the higher RS content, higher thermal properties, higher pasting values, higher solubility, lower syneresis to freezing, and thawing when compared with oven dried CCS. These properties of freeze dried CCS represented a unique starch for food ingredient usage of chestnut.     

湿热处理对板栗淀粉结构及理化性质的影响

以板栗淀粉为对象,采用湿热处理方法对板栗淀粉进行物理改性,通过控制湿热处理的时间(2~18 h)、温度(80~120℃)、含水量(10%~30%),制得不同处理条件下的板栗淀粉。随着湿热处理程度的加强,板栗淀粉的溶解度、膨胀度均减小,其中,处理温度的影响较大;湿热处理后板栗淀粉的透光率下降;板栗原淀粉颗粒的表面光滑,多数呈椭圆形、梨形等;湿热处理后,淀粉颗粒大部分保持原状,但部分颗粒表面出现轻微的凹陷和破损;X-射线衍射图谱显示虽然淀粉结晶型仍为C型,但淀粉颗粒内部有新的结构出现。     

不同板栗品种(系)抗性淀粉综合评价

对72个板栗品种(系)栗仁中总淀粉、支链淀粉、直链淀粉、抗性淀粉、以及含水量等重要性状分析的测定,为不同板栗品种(系)的利用提供参考。结果表明,不同板栗品种(系)大小、色泽、形状不同;板栗品种(系)中总淀粉的质量分数在51.33%以上,质量分数最高为‘燕秋’,高达71.21%,质量分数最低的是‘波叶-8’,为51.33%;直链淀粉中含量最高的是‘燕秋’,质量分数为18.56%,最低的是‘大兰口’,质量分数为2.43%;支链淀粉含量最高的是‘金丰’,质量分数为58.35%,最低的是‘小官10’,质量分数为35.2%。板栗中含有较高的抗性淀粉。对不同板栗品种(系)中抗性淀粉进行综合评价,抗性淀粉含量最高的品种是‘燕秋’,质量分数为22.2%;最低的是‘徐玉明道’,质量分数为3.44%。通过对不同板栗品种(系)的淀粉进行相关性分析,表明板栗栗仁中直链淀粉与支链淀粉呈极显著负相关,支链淀粉与总淀粉呈极显著正相关,抗性淀粉与直链淀粉呈显著正相关。     

Morphological,physicochemical, and pasting properties of modified water chestnut (Trapabispinosa) starch

Selected physicochemical properties of native and modified water chestnut starch (Trapabispinosa) were studied. Single- and dual-modifications were carried out by pregelatinization, acetylation and acid-thinning methods. Chemical modification created unevenness on the surface of starch granule. Swelling power, solubility, and water retention capacity were improved by all modification techniques used. The peak viscosity was reduced in all modified starches as compared to native water chestnut starch. The setback value which is an indication of retrogradation (re-association of starch molecules) tendency in the starch paste was reduced after pregelatinization and acid-thinning but increased by acetylation.     

Effect of heat-moisture treatment on the formation and physicochemical properties of resistant starch from mung bean (Phaseolus radiatus) starch

Mung bean starch was subjected to a range of heat-moisture treatments (HMT) based on different moisture contents (15%, 20%, 25%, 30%, and 35%) all heated at 120 °C for 12 h. The impact on the yields of resistant starch (RS), and the microstructure, physicochemical and functional properties of RS was investigated. Compared to raw starch, the RS content of HMT starch increased significantly, with the starch treated at 20% moisture having the highest RS content. After HMT, birefringence remained at the periphery of the granules and was absent at the center of some granules. The shape and integrity of HMT starch granules did not change but concavity was observed under scanning electronic microscopy. Apparent amylose contents of HMT starch increased and the HMT starch was dominated by high molecular weight fraction. Both the native and HMT starches showed A-type X-ray diffraction pattern. Relative crystallinity increased after HMT. The gelatinization temperatures (To, Tp, and Tc), gelatinization temperature range (Tc–To) and enthalpies of gelatinization (ΔH) increased significantly in HMT starch compared to native starch. The solubility increased but swelling power decreased in HMT starches. This study clearly shows that the HMT exhibited thermal stability and resistance to enzymatic hydrolysis owing to stronger interactions of starch chains in granule.