Silver and Gold Nanoparticles Embedded in Potato Starch Gel Films

Facile and environmentally friendly method of the preparation of silver and gold nanoparticles embedded in potato starch matrix (Sp) was developed. UVVIS spectroscopy, transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectra confirmed formation of ball shaped Ag and Au nanoparticles situated within the polysaccharide template. EDS spectra confirm presence of silver and gold nanocrystals in the obtained composites. Differential scanning calorimetry (DSC) showed that Sp/Au composite started to decompose earlier. The decomposition is slower and two-step, in contrast to Sp and Sp/Ag. NanoAg accelerates carbonization. Molecular weights of polysaccharide chains of the matrix were estimated with the size exclusion chromatography coupled with multiangle laser light scattering and refractometric detectors (HPSEC-MALLS-RI). Formation of nanosilver containing composites led to partial depolymerisation of polysaccharides from the amylose fraction. In the case of nanogold we observed depolymerisation of polysaccharide chains from both fractions.

Synthesis and Characterization of Hydrogels Based on Potato Starch/Poly(vinyl Alcohol)/N,N′-Methylenebisacrylamide

Several hydrogels were synthesized by free-radical polymerization in an aqueous medium based on potato starch(PS),poly(vinyl alcohol)(PVA),and N,N′-Methylenebisacrylamide(MBAm),being possible to study these hydrogels as a function of the proportion of components incorporated.In this way,the products generated from the synthesis were characterized by swelling and deswelling kinetics,the first swelling being verified with Schott and statistical models,allowing to contrast the proximity between the experimental and theoretical behavior.Additionally,water retention in soil(R%),spectroscopy(FTIR),morphological(SEM),and thermal(TGA and DSC)analysis allowing to know the intrinsic characteristics of the material,increasing in general terms the knowledge of this type of material.In this context,it was possible to verify the characteristics and effectiveness of the synthesis and crosslinking of the main components.The experimental results obtained show that the synthesized hydrogels present representative swellings consistent with kinetic and statistical models,optimal thermal stability depending on the amount of crosslinker,and excellent water retention in environments such as soil,presenting it as an excellent alternative to be used in agro-industrial applications in an eco-friendly way.

Rheological and Thermal Properties of Potato Starch

Particle size, rheological and thermal properties of potato starch from Yunnan province of China was in-vestigated. The particle size ranges from 0.429-102.3 um determined by laser light-scatter. The major flow type of 6 w/v% potato starch was shear-thinning fluid even the shear rate up to 800·s-1, and the gel formed by 6 w/v% potato starch fell to weak gel for its little difference between G' and G'', high dependence on frequency and low value of G'(Pa). The hardness and cohesiveness of potato starch gel were 31.3 g and 131.9 g·s, respectively. The thermal properties of potato starch were also determined by DSC at the starch:water=3:1. The To, Tp, and ΔH of potato starch were 62.23℃,67.31℃, and 2.22 J·g-1.

Mechanochemical degradation of potato starch paste under ultrasonic irradiation

In the paper, changes in the molecular weight, the intrinsic viscosity and the polydispersity (molecular mass distribution) of treated potato starch paste were studied under different ultrasonic conditions which include irradiation time, ultrasonic intensity, potato starch paste concentration, and distance from probe tip on the degradation of potato starch paste. Intrinsic viscosity of potato starch paste was determined following the ASTM (American Society for Testing and Materials) standard practice for dilute solution viscosity of polymers. Molecular mass and polydispersity of potato starch paste were measured on GPC (Gel Permeation Chromatography). The results showed that the average molecular mass and the intrinsic viscosity of starch strongly depended on irradiation time. Degradation increased with prolonged ultrasonic irradiation time, and the increase of ultrasonic intensity could accelerate the degradation, resulting in a faster degradation rate, a lower limiting value and a higher degradation extent. Starch samples were degraded faster in dilute solutions than in concentrated solutions. The molecular mass and the intrinsic viscosity of starch increased with the increase of distance from probe tip. Our results also showed that the polydispersity decreased with ultrasonic irradiation under all ultrasonic conditions. Ultrasonic degradation of potato starch paste occured based on the mechanism of molecular relaxation of starch paste. In the initial stage, ultrasonic degradation of potato starch paste was a random process, and the molecular mass distribution was broad. After that, ultrasonic degradation of potato starch paste changed to a nonrandom process, and the molecular mass distribution became narrower. Finally, molecular mass distribution tended toward a saturation value.

Rheological properties of sweet potato starch before and after denaturalization

Based on the sweet potato starch,cationic starch,acetic starch and cationic-acetic compoundedly modified starch were made through chemical denaturalization.The above three kinds of static rheological parameter and dynamic rheological parameter were measured,respectively.The experimental result reveals that the thermal stability of starchy viscosity increases after chemical denaturalization.Under the condition of identical shearing rate,the shear stress of cationic-acetic ester compoundedly modified sweet potato starch paste is the largest among these kinds of sweet potato starch.This attributes to a phenomenon of shearing thinning.Furthermore,raw sweet potato starch has a larger gel intensity than that of modified starch.

Sweet Potato Starch as a Carbon Source for Growth and Glucoamylase Production from <i>Aspergillus niger</i>

A mesophilic strain of Aspergillus niger isolated from cassava effluent samples produced extracellular glucoamylase in submerged culture containing 2% (w/v) soluble or sweet potato starch. On soluble starch medium the maximum glucoamylase activity in the culture filtrate was 9.40 U/mg compared to 8.24 U/mg on sweet potato starch culture filtrate. The mycelial dry weight for both media was 494 and 418 mg respectively. The maximum glucoamylase activity was obtained at a growth temperature of 40&deg;C and pH 4.5. The implication is that the bioprocess of utilizing sweet potato starch in the culture is attractive due to its relatively cheaper availability in Nigeria, making it even more favorable when economics is considered.

Effects of Light Radiation Absoption on the Resistance of Sweet Potato Starch-Based Bioplastics

The strength of starch-based bioplastics is a challenge, we tried to overcome this limitation by using electromagnetic radiation in the visible range. Synthetically obtained retrograde bioplastics were subjected to radiation from an Edison-type incandescent lamp. A cross-linked network is obtained within the bioplastic matrix considerably attenuating the usual hygroscopicity of starch and increasing the ability to resist rupture. After this positive behavior, the bioplastics were colored in order to optimize the action of light radiation. The results show a stronger and more compact bioplastic. The green-colored bioplastics show the best performance in the optimization of the resistance.

Characterization and Expression Analysis of Starch Branching Enzymes in Sweet Potato

Spatial and temporal expression patterns of Sbel and Sbe2 that encode starch branching enzyme （SBE） Ⅰ and Ⅱ, respectively, in sweet potato （Ipomoea batatas L.） were analyzed. Expression of both genes in Escherichia coli indicate that both genes encoded active SBE. Analysis with real-time quantitative polymerase chain reaction technique indicates that IbSbel mRNA was expressed at very low levels in leaves but was the predominant isoform in tuberous root while the reverse case was found for lbSbe2. The expression pattern of IbSbel, closely resembles that of AGPase S, a gene coding for one of the subunits ofADP-glucose pyrophosphorylase, which is the key regulatory enzyme in the starch biosynthetic pathway. Western analysis detected at least two isoforms of SBE I in tuberous roots, those two isoforms showed adverse expression patterns with the development of the tuberous roots. Expression of the two IbSbe genes exhibited a diurnal rhythm during a 12-h cycle when fed a continuous solution of sucrose. Abscisic acid （ABA） was aother potent inducer of IbSbe expression, but bypassed the semidian oscillator.

Mapping QTL underlying tuber starch content and plant maturity in tetraploid potato

Tuber starch content and plant maturity are two important agronomic traits of potato. To investigate the complex genetic basis of these traits in the cultivated potato, as well as the relationship between them, we developed a linkage map in a tetraploid population of 192 clones derived from the cross Longshu 8 × Zaodabai and mapped quantitative trait loci(QTL) for tuber starch content and plant maturity using data collected in three diverse environments over two years. We detected eleven QTL for tuber starch content distributed on seven chromosomes, of which four, on chromosomes I, II, and VIII, were expressed in at least three environments. For plant maturity, we identified six QTL on chromosomes II, IV,V, VII, and XI, one of which, on chromosome V, showed LOD peaks ranging from 45.2 to 62.5 cM and explained 21.6%–26.6% of phenotypic variation was expressed in five of the six environments. Because the reproducible QTL for plant maturity and tuber starch content mapped to different chromosomes and neither overlapping QTL, nor any genetic interaction between QTL were detected, we infer that tuber starch content and plant maturity are controlled by independent genetic loci. This inference supports the prospect of breeding potato for both early maturity and high starch content.

Effects of RNAi Silencing of SSIII Gene on Phosphorus Content and Characteristics of Starch in Potato Tubers

The sense and antisense fragments of the soluble starch synthase （SSII1） gene and the intron fragment of somatic embryogenesis receptor-like kinase （SERK1） gene were cloned from potato using PCR techniques. The RNAi plant expression vectors pBI-SSIII-RNAi and pBIC-SSIII-RNAi were constructed which containing fusion fragment of ＂sense fragment-intron-antisense fragment＂ driven by the constitutive expression promoter CaMV 35S and the tuber-specific expression promoter CIPP, respectively. The putative transgenic plants of potato cultivars Kexin-1 and Kexin-4 were obtained using Agrobacterium-mediated transformation method. PCR assay showed that the interference fragment of SSlll gene was integrated into potato genome. The RT-PCR analysis showed that the expression of SSlll gene was repressed apparently on the transcription level. Starch granules of the transgenic potato plants were different in morphology and became cracked in starch granule centre compared with the non-transgenic control plants. The amylose content of starch was increased by 2.68-29.05%, amylopectin to amylose ratio of starch had declined significantly, and the phosphorus content of the starch of the transgenic plants was reduced 9.94-58.36% compared with control plants. The results could provide certain foundation for improvement of potato starch quality.

Effects of Agrobacterial<i>rol</i>-Genes on the Thermodynamic and Structural Features of Starches Extracted from Potato Microtubers

Wild-type potato (Solanum tuberosum L.) plants and their transformants harboring agrobacterial rolB or rolC genes under control of the patatin class I promoter were cultured in vitro. These plants were used as a source of single-node stem cuttings. The structure of native starch in tubers formed on cuttings was determined using methods of X-ray scattering and differential scanning microcalorimetry (DSC). It was found that in starch from tubers of rolB plants the melting temperature of crystalline lamella was lower and their thickness was less than that in wild-type potato. In tubers of rolC plants starch differed from starch in wild-type plants by a higher melting temperature, reduced melting enthalpy, and a greater thickness of crystalline lamellae. The melting of starch from tubers of rolC plants proceeded as the melting of two independent crystalline structures with melting temperatures of 338.0°K and 342.8°K. Overall data show that starches of different structure can be obtained by using transgenic approach.

Coronatine Induces an Accumulation of Anthocyanin and Starch in Purple-fleshed Sweetpotato(Ipomoea batatas Lam.)

[Objective]The objective of this research was to examine the effects of COR on anthocyanin and starch content in storage roots of two PFS genotypes,and to explore the relationships between anthocyanin synthesis and starch accumulation.[Method]A field experiment was carried out to determine the changes in yield components,yield,contents of anthocyanin and starch,activities of phenylalanine ammonia-lyase(PAL)and adenosine 5-diphosphate glucose pyrophosphorylase(AGPase)in two genotypes of PFS(Ipomoea batatas L.,var.‘Ayamurasaki’and‘Jishu18’).[Result]The application of COR significantly increased starch and anthocyanin content in storage roots of Jishu18 across developmental stages by inducing the activities of PAL and AGPase,and finally enhanced yield by promoting fresh weight of storage roots.Ayamurasaki was insensitive to treatment with COR although its PAL activity temporally increased.The starch and anthocyanin content of Aya,and the anthocyanin content of Jishu18 increased progressively across developmental stages with or without COR application,but the starch content of Jishu18increased initially,then decreased before increasing again without application of COR.Treatment with COR reduced downward trend of starch accumulation in Jishu18.Thus,the effect of COR on accumulation of anthocyanin and starch in storage roots of PFS differs according to genotypes.[Conclusion]The application of0.05μmol/L COR may increase starch and anthocyanin content in PFS genotypes with lower starch and anthocyanin content in storage roots.

不同油炸条件对挂糊肉制品品质的影响

【目的】探究油炸参数对挂糊肉制品品质的影响及淀粉糊的作用。【方法】通过改变油炸温度和油炸时间,借助质构仪、傅里叶红外光谱仪、X-射线衍射仪等仪器,研究挂糊肉制品的品质和淀粉糊的结构变化,采用皮尔逊(Pearson)相关性分析探讨淀粉糊的结构改变对挂糊肉制品品质形成的贡献。【结果】随着油炸温度的升高和油炸时间的延长,挂糊肉制品亮度值升高,红度值与黄度值降低,水分含量降低,硬度与咀嚼性无显著变化,总体感官得分逐渐上升;表面淀粉的结晶结构及分子构型遭到破坏,含油率上升,直至19.4%;包裹淀粉糊可以提高挂糊肉制品亮度值,减少水分流失,并降低油炸挂糊肉制品的硬度与咀嚼性;直至温度达到170℃或时间延长至140 s以后时,淀粉的结晶衍射峰逐渐平缓,含油率下降,水分含量进一步降低至46.13%,硬度与咀嚼性迅速升高至819.12 g和472.18 g,此时挂糊肉制品表面呈现金黄色,口感质地最为酥脆;淀粉R 1值降至最低值0.9982,结构被破坏转为无序,对肉的保护作用降低,但此时挂糊肉制品的感官得分达到最高点。【结论】马铃薯淀粉糊可以提高油炸肉制品的亮度值,增加水分含量及出品率,并降低硬度与咀嚼性,进而提高挂糊肉制品的感官评分。

改性甘薯淀粉及其在食品工业中的应用研究进展

甘薯淀粉常作为粉丝和粉条等食品加工原料,具有稳定和增稠作用。但受其固有性质的限制(如热稳定性差、淀粉糊透明度低等),难以满足现代食品工业发展的需求,而改性(如物理法、化学法、酶法及复合法等)能赋予甘薯淀粉良好的功能、流变学和加工特性(如抗老化性、淀粉糊透明度高、凝沉性小、冻融稳定性好、抗酸性和成膜性好等),可用于改善食品的物化特性、质构特性及食用品质。该文首先分析了甘薯淀粉的结构及性质,并总结了改性方法,最后概述了甘薯淀粉在食品工业(从粉丝、面制品、调味料及其他食品等方面)中的应用情况,以期为扩大甘薯淀粉资源的研究和应用提供参考。

不同品种马铃薯淀粉功能性质的相关性及主成分分析

分析黑龙江、甘肃、北京3个地区的11个马铃薯品种制备得到淀粉的水分含量、色泽、直链淀粉含量、透光率、碘蓝值、溶解度、膨胀度、胶稠度、质构特性。结果显示,不同品种各指标差异显著,直链淀粉质量分数的变化范围是10.96%~16.64%;相关性分析发现不同品种的各品质指标间存在显著的相关性,直链淀粉与淀粉提取率(r=0.4683)、膨胀度(r=0.5209)、硬度(r=-0.4721)、咀嚼性(r=-0.4496)分别呈显著的相关性。主成分分析结果显示,前4个主成分的特征根大于1,可以解释原有数据的信息,综合主成分得分,陇薯9号的综合值排名第一,荷兰薯的综合值最低。

湿热处理对红薯淀粉特性的影响

为了研究湿热处理对红薯淀粉理化和结构等特性的影响,以五种红薯淀粉为实验对象,测定并分析湿热处理后淀粉溶解度、膨润力、持水力、透光率、凝沉性等理化特性的变化情况,进而探明湿热处理对不同初始含水量红薯淀粉吸水特性及晶体结构的影响规律。结果表明,经湿热处理后红薯淀粉的溶解度、膨润力、凝沉性与透光率均较原淀粉降低,持水力均增强,且五种红薯淀粉均呈现相同趋势,说明红薯品种与湿热处理对淀粉性质的影响规律无显著相关性。经湿热处理后红薯淀粉未见新的衍射特征峰,晶体类型仍为C型,而衍射强度和结晶度降低。湿热处理淀粉吸水达到平衡所需要时间较原淀粉短,且饱和吸水量较原淀粉有减小的趋势。利用Peleg模型方程模拟湿热处理后红薯淀粉的吸水规律,并计算出浸泡动力学吸水常数K1和K2,确定了淀粉的吸水动力学方程,可预测湿热处理后红薯淀粉在浸泡过程中的水分含量。

魔芋凉粉的配方及工艺优化

选用红薯淀粉和魔芋粉为主要原料,以感官评分及质构参数为实验指标,通过单因素试验考察红薯淀粉添加量、魔芋粉添加量、加热温度、加热时间对产品感官及质构的影响,并选择正交试验来优化魔芋凉粉的配方及工艺.结果表明,产品的最佳配方为(以产品质量计):红薯淀粉16 g/100g、魔芋粉0.5 g/100g、纯净水83.5 mL;最佳工艺条件为:加热温度为100℃、加热时间为11 min.该条件下制备的凉粉产品质地细腻,表明光滑,弹性好,不粘牙,质构特性较好,综合评分为87.4分.

4种植物源性成分多重real-time PCR检测方法的建立及其在食用淀粉中的应用

建立一种可同时快速检测红薯、木薯、马铃薯、玉米源性成分的多重实时聚合酶链式反应(real-time polymerase chain reaction,real-time PCR)方法。分别以红薯g3pdh基因、木薯g3pdh基因、马铃薯UGPase基因、玉米zSSIIb基因为靶基因设计特异性引物和TaqMan探针,以18S rRNA基因为内参基因,建立多重real-time PCR方法,开展方法学验证,并对不同掺入比例模拟样品和实际淀粉样品进行检测。结果显示,该方法具有高通量、特异性强、灵敏度高等优点。与15种非目标源性均无交叉反应;对目标DNA的检测灵敏度可达到3×10^(-3) ng/μL,且具有良好的线性关系和扩增效率;对淀粉样品的检出限可达0.1%,对50份实际样品进行检测,结果与参比方法一致,说明建立的多重real-time PCR法可用于食用淀粉种类掺假鉴别检测。

含紫薯花青素的槟榔芋淀粉薄膜性能及其应用

开发含紫薯花青素(PSPA)并可生物降解的槟榔芋淀粉薄膜(TSF),并研究其光学性能、厚度、含水率、水溶性、颜色、总酚含量、抗氧化活性、红外光谱和微观结构等性能,初步探讨TSF对鲜切莴笋、鱼肉和猪肉储存过程中新鲜度的指示作用。研究表明TSF的紫外-可见光谱和PSPA溶液的光谱变化规律是一致的,表明PSPA与槟榔芋淀粉具有良好的成膜机制。TSF厚度适中,含水率为39.17%,水溶性为36.93%;TSF的DPPH清除率达到94%,表明TSF的抗氧化活性高。将TSF应用于鲜切莴笋、鱼肉和猪肉的新鲜度监测,TSF先呈现淡紫色,随着时间推移,鲜切莴笋、鱼肉和猪肉逐渐腐败变质,48 h后,TSF在莴笋中呈现蓝紫色、猪肉中呈现浅绿色、鱼肉中呈现淡黄色。