Effect of acid treatment on the physicochemical and structural characteristics of starches from different botanical sources

Starch and starch derivatives (maltodextrins) are used as encapsulating materials. Starch for use as encapsulating material could be subjected to mild acid treatment. However, the granule size and organization of starch components (AM and AP) play an important role in the acid treatment. The aim of this research was to produce modified starch that might be used as encapsulate material, applying moderate acid‐treatment with 3 N sulphuric acid in a ratio 1:5 w/v for 3 h at 60°C, in starches from different granule size, evaluating their morphological, physicochemical, and structural features. Acid treatment has an effect in the AM content and the outcome was higher in starch with larger granule size. Bimodal granule size distribution was found in acid‐treated rice and maize starches. Erosion and exo‐corrosion were observed in acid‐treated starches with SEM. The XRD pattern did not change with the acid treatment, the native and acid‐treated samples showed similar crystallinity values, except rice starch. The branching degree was higher for modified potato starch, showing higher branching points, modified starches had shorter chains with increased A‐chains, and decreased B3+ chains, and the effect was higher in cereal starches; modified starches had a higher degree of retrogradation and they did not show pasting properties. The internal organization given by the granule size is an important parameter in the acid treatment of starches as it affected their physicochemical and structural features, and in the end, their functionality as encapsulate agent.     

Characteristics and application of octenyl succinic anhydride modified waxy corn starch in sausage

Native and acid‐hydrolyzed wx corn starches were modified by octenyl succinic anhydride (OSA) in aqueous slurry systems. The characteristics of the modified wx corn starches and their effects on chicken meat sausages were evaluated by means of FT‐IR, rapid visco analyser, SEM, and texture profile analysis. FT‐IR spectroscopy indicated that the ester carbonyl groups in the OSA modified native and acid‐hydrolyzed starches were characterized at 1725 cm⁻¹. The process of OSA modification could achieve starch derivatives, which had higher viscosities, better paste clarity and freeze–thaw stability than the native counterparts. Texture results showed that the hardness, springiness, cohesiveness, and chewiness of the sausage increased as OSA‐H0 was added (p < 0.05). SEM revealed that the sausages with native wx corn starch had larger and uneven pores, while it was comparatively compact for the sausages with OSA starches. The OSA modified wx corn starch offered a great potential to be used in meat products to enhance textural quality.     

Chemical composition,digestibility and emulsification properties of octenyl succinic esters of various starches

Octenyl succinate starches are commonly used as emulsifiers and texturizing agents in many food-systems. Rice, tapioca, corn, wheat and potato starches were modified with octenyl succinic anhydride (OSA) at 3% level. Structural characterization, molecular weight, starch digestibility and physical properties of starch granule stabilized emulsions were studied for modified starches. Modified potato (0.022) and wheat (0.018) starches had the highest and lowest degrees of OSA substitution, respectively. For all starches, amylose and amylopectin molecular mass was significantly (P < 0.05) lower for OSA starches. OSA modification may have hydrolyzed the small amylose and amylopectin chains, or caused rearrangement of the starch molecules. Although the starch modification improved emulsification properties, botanical source showed more influence on this parameter. Overall, botanical source had more influence on functional properties than degree of substitution. Further studies on OSA group distribution and fine molecular structure of amylopectin and relationship with functional properties will be important.     

Steady and dynamic shear rheology of starches from different oat cultivars in relation to their physicochemical and structural properties

Starches isolated from eight oat cultivars were tested for their physicochemical, structural, and rheological properties. The isolated starches had low levels of ash and nitrogen contents with amylose ranging from 21.8 to 32.3 g/100 g. The amount of water released from starch gels decreased significantly (p < 0.05) with increase in freeze thaw cycle. The scanning electron micrographs revealed the presence of polygonal to irregularly shaped starch granules. All the starches exhibited A-type X-Ray diffraction pattern typically characteristic of cereal starches. The rheological properties of pastes were well described by the Herschel-Bulkley model at a shear rate of 0–100 s^?1 (R² > 0.99). The starch pastes behaved like a pseudoplastic fluid and exhibited shear thinning fluid characteristics with values of flow behaviour index considerably less than 1. Both the storage and loss moduli of the pastes increased sharply initially and then dropped after reaching the gelatinization peak. The magnitude of the dynamic rheological parameters varied significantly (p < 0.05) between the cultivars. All the starch pastes were highly elastic than viscous as evidenced by the lower tan δ values. Structure property relationships were established between starches using principal component analysis.     

Micellar properties of OSA starch and interaction with xanthan gum in aqueous solution

Octenyl succinate (OSA) modified starches are used, as emulsifiers and stabilizers, in many food, cosmetics and pharmaceutical products. The aim of this study was to determine critical micellar concentration (CMC) of two different octenyl succinate modified waxy corn starches at 25 °C, and to examine possibility of their interactions with xanthan gum in aqueous solution. The CMC was determined by viscometry, conductometry, surface tension and dye solubilization. The CMC values for two OSA starches (OS1 and OS2) varied from 0.050 to 0.088 g/100 cm³ and from 0.041 to 0.081 g/100 cm³ respectively, depending on applied technique. The same techniques were used for investigation of the interactions between OSA starch and xanthan gum. The addition of xanthan gum decreases the specific viscosity and increases surface tension and the CMC values compared to the single OSA starch solutions.     

Functional characterisation of potato starch modified by specific in planta alteration of the amylopectin branching and phosphate substitution

Potato starch was modified in planta by antisense of the starch branching enzyme I (SBE I), and the starch branching enzyme II (SBE II) both simultaneously and individually generating B group starches. Another group of starches, G group starches, was generated by over expression of the E. coli glycogen branching enzyme (E. coli glgB). The content of covalently esterified phosphate increased in the B group starches and decreased in the G group starches. The content of phosphate correlated with length of debranched amylopectin chains measured by HPAEC-PAD, and with gelatinisation mid temperature (T_m) and change in enthalpy (ΔH) measured by differential scanning calorimetry (DSC). Freeze/thaw stability measured by ¹H pulse-NMR and cohesiveness measured by texture profile analysis (TPA) was in the same range in all starch samples, whereas gel hardness was inversely correlated to phosphate content. No correlations between the pasting properties measured by rapid visco analysis (RVA), gel strength (G′) measured by small deformation oscillation testing or any structural parameter could be revealed. The data set was mined using multivariate statistics. Based on this data starch samples could be separated into the two groups B and G, in accordance with their original transformation strategy.     

Starch Gelation Process Observed by FT-IR/ATR Spectrometry with Multivariate Data Analysis

For directly observing changes related to the gelation process of starch, IR spectra of starch in water while heating were obtained using FT-IR/ATR spectrometry. Relationships between gelation and spectral changes were examined using factor analysis, evolving factor analysis (EFA) and three-way principal component analysis (PCA). Absorption at 3300 and 1610 cm^-1 decreased with temperature but absorption at 1000 cm^-1 increased. The factor score plot patterns of amylose, amylopectin and rice starches were similar but those of potato and corn starches were unique. EFA indicated variances relating to changes caused in starch and water as different factors. Loadings of the starch component 2 in three-way PCA correlated with starch granule sizes.     

One-Dimensional Nuclear Magnetic Resonance Studies of Starch and Starch Products

The use of one-dimensional Nuclear Magnetic Resonance (NMR) spectroscopy as applied to structural studies of starch, starch products and glycogen is reviewed. Proton, carbon-13 and phosphorus-31 NMR spectra of a range of starches and starch products are described. These spectra, particularly carbon-13 NMR spectra, permit one to obtain structural information regarding these molecules. From the proton NMR spectra, which can be obtained with greater sensitivity, it is possible to determine the DP (degree of polymerization, the average number of glucose units per molecule) and the degree of branching (the proportion of glucose units which are (1→6) linked) without recourse to chemical or enzymatic methods. Moreover, the anomer distribution of the reducing sugars can be determined by ¹H or ¹³C NMR. Finally, some examples of the application of NMR to follow the time course of enzymatic digestion and sugar anomerization are discussed, as is the solid-state NMR of starch and glycogen. The phosphorus-31 NMR spectra provide information about the nature of the phosphate groups in potato starch.     

不同杂粮淀粉物性的研究

为丰富和拓展特色杂粮深加工技术和品质控制方法,以莜麦、高粱、薏苡、小米和甜荞5种特色杂粮淀粉为对象,进行色度、粒径、直链淀粉含量、溶胀度及流变性等特性的研究。结果表明,5种淀粉L*值为94.34~97.15,符合淀粉色度要求,平均粒径分布介于1.572~16.989 μm。淀粉中直链淀粉含量为5.08%~30.97%,存在显著性差异(P<0.05)。热学特性方面,莜麦淀粉的峰值温度Tp、终止温度Tc和糊化焓△H显著低于其他淀粉(P<0.05)。淀粉溶胀性与温度有关,随温度增加而增大,95 ℃薏苡淀粉溶胀度最大为20.282 g/g,但其冻融析水率最低。流变性分析发现,5种淀粉糊均为假塑性流体,表现出剪切稀化特性。综合分析,不同种类杂粮淀粉的物理特性间存在差异性,应根据加工目的选择适合的淀粉,并为淀粉的深加工与品质控制提供理论依据和参考。     

糯小麦辛烯基琥珀酸淀粉酯的性质研究

进行了糯小麦辛烯基琥珀酸淀粉酯性质的测定,结果表明,经过OSA改性之后,糯小麦辛烯基琥珀酸淀粉酯糊的粘度、透明度、凝沉性和冻融稳定性得到显著改善。当取代度由0增加至0.0144时,淀粉糊的峰值粘度由3228.00cP增加到5309.00cP。而峰值时间却由3.4min降至2.9min。透光率由28.31%提高到69.52%,25℃下静置14d时析出水的体积由22.63mL降低为0.23mL,经过4次冻融循环后的析水率由54.25%降至3.72%。并且,蔗糖与SSOS相互作用,使淀粉糊的透明度和凝沉性增加,抗老化稳定性增强;NaCl使淀粉糊的透光率降低,凝沉性下降,淀粉糊不稳定,易于老化。     

Noodle quality affected by different cereal starches

To investigate the effects of starch characteristics on the quality of noodle making, white salted noodles (WSN) made from reconstituted flours, in which the wheat starch was substituted by different cereal starches, including waxy and non-waxy rice starches, waxy wheat starch and waxy corn starch, were prepared. The rheological properties of raw WSN were mainly influenced by the size of starch granules, where the small starch granules, such as for rice starches, exhibited high amounts of water absorption during dough preparation and a dense packing of starch granules inside a thin gluten-strand network. The rheological properties of cooked WSN were mainly dominated by the amylose content and fine structure of the amylopectin, which resulted in the differences in water absorption and cooking time required for cooked WSN.     

13C CP/MAS NMR Spectroscopy of Native and Acid Modified Starches

¹³CP/MAS NMR spectroscopic studies of some starches from cereals (wheat, maize and finger millet), pulses (green gram, chick pea), tuber (potato) and root (tapioca), and their respective acid (HCI, HNO₃) modified starches were carried out. While cereal starches exhibited a triplet signal for their anomeric carbons, pulse, tuber and root starches showed doublets. Line width changes in signals indicated that debranching in the above modified starches led to narrowing of C₆ signals (more pronounced in the case of potato and tapioca starches) and were consistent with the release of branching strains. Potato starch, both native and modified, was found to be different from other starches as inferred from the chemical shift values for their anomeric carbons and line shape. The dihedral angle (ϕ′2) calculated from chemical shift values for C₁ and conformation of dihedral angel (x) as predicted from chemical shift of C₆ are discussed with respect to structural organization.     

辛烯基琥珀酸淀粉的干法制备及其黏度性质

以木薯淀粉为原料,研究了辛烯基琥珀酸淀粉的干法制备工艺及其性质.结果表明,反应体系的碱性范围对酯化反应的影响较大,提高反应温度和延长反应时间都能增加产物取代度,但取代度增加到一定程度后趋于稳定.干法制备的辛烯基琥珀酸淀粉具有较低的糊化温度、峰值黏度和热糊黏度,糊的崩溃性减弱,冷糊稳定性有所提高,凝胶性增强.     

Synthesis of Octenyl Succinic Derivative of Mechanically Activated Indica Rice Starch

Indica rice starch was mechanically activated by ball milling and then esterified by octenyl succinic anhydride (OSA) in aqueous slurry systems. The process of esterification was studied with respect to the time of mechanical activation, OSA/starch ratio, temperature, pH, starch slurry concentration and reaction time. The effects of these reaction conditions were evaluated on the basis of degree of substitution (DS) and reaction efficiency (RE). The results indicated that mechanical activation could enhance the reaction of OSA and starch. The DS and RE of OSA starch increased sharply when the time of mechanical activation increased from 0 h to 10 h, after which it was not significantly affected until 50h. The suitable conditions for the synthesis of OSA starch from Indica rice starch that was mechanically activated for 10 h (MAIS10) were an OSA/starch ratio 3%, temperature 35°C, pH 8.5, starch slurry concentration 12.5% and reaction time 3h. For native Indica rice starch (NIS), all conditions were identical to MAIS10 except for the starch slurry concentration of 40% and reaction time of 4 h. The maximum DS and RE of OSA‐MAIS10 (0.02037, 88.03%) was higher than that of OSA‐NIS (0.01700, 73.46%) at OSA/starch ratio 3%. The esterification of MAIS10 with OSA showed a low sensitivity to pH and a higher stability than OSA‐NIS. Scanning electron microscopy (SEM) revealed that the modified OSA starches did not show any detectable change in the morphological structural characteristics. The esterification between OSA and starch was confirmed by Fourier transform infrared (FT‐IR) spectroscopy.     

辛烯基琥珀酸淀粉酯在速冻水饺中的应用

采用黏度速测仪和分光光度计测定糯玉米淀粉和大米淀粉辛烯基琥珀酸酐改性前后糊的性质,并将其按照不同比例分别添加到面粉中,研究其对速冻水饺品质的影响。结果表明：辛烯基琥珀酸酐改性使糯玉米淀粉和大米淀粉糊的透明度提高、凝沉性降低、冻融稳定性得到改善。添加不同比例的糯玉米辛烯基琥珀酸淀粉酯和大米辛烯基琥珀酸淀粉酯可增大面粉的黏度,提高饺子皮的硬度、弹性和咀嚼性(P ＜ 0.05);其中添加5% 预糊化糯玉米辛烯基琥珀酸淀粉酯的饺子冻裂率最低,并且饺子的色泽、透明度、韧性和细腻度最好。     

Structural and some nutritional characteristics of Velvet bean (Mucuna pruriens) and Lima bean (Phaseolus lunatus) starches

Velvet bean (Mucuna pruriens) and lima bean (Phaseolus lunatus) starches were isolated from seeds and their structural characteristics evaluated using XRD, size‐exclusion chromatography and light scattering analyzes. Total starch, available starch, RS and in vitro digestibility were also determined. Structural and nutritional characteristics of Velvet bean and Lima bean starches were compared to those of commercial corn starch. The legumes starches presented a C‐type XRD pattern and crystallite sizes of 43.1 Å for velvet bean and 48.3 Å for lima bean. Lima bean starch average molar mass (4.9 × 10⁶ g/mol) was slightly higher than the velvet bean starch (3.04 × 10⁶ g/mol). Size‐exclusion chromatography indicated structural similarity between the lima bean and corn starches which differed from that of the velvet bean starch. Hydrodynamic radius (R_H) for the velvet bean and lima bean starches was 45.5 and 55 nm, respectively, and their radius of gyration (R_G) was 67.7 and 82.5 nm, respectively. Total starch content in all three starches was greater than 98%. Their complex crystalline structure provided the legume starches lower in vitro digestibility values than the corn starch. RS content in both the velvet bean starch (7.72%) and lima bean starch (5.66%) was higher than in the corn starch, essentially qualifying these polysaccharides as natural dietary fiber sources, with the associated physiologic advantages.     

Relationship between α-amylase degradation and physico-chemical properties of sweet potato starches

Six varieties of sweet potatoes, grown under identical conditions, produced starches that displayed different characteristics. Susceptibility to pancreatic α-amylase varied between starches produced by the different clones. Structural characteristics at various levels, such as ratio of major fractions, size of amylose, gelatinization temperature and granule morphology, were also different between clones. Correlating structural attributes with susceptibility led to the suggestion that granule structure, including amylopectin: amylose ratio and molecular associations, were important critical factors in the hydrolysis of sweet potato starch granules. High amylopectin content of sweet potato starch was associated with a high gelatinization temperature and correspondingly less susceptibility to α-amylase attack. The hydrolysis pattern was correlated with degree of hydrolysis. Extensive surface erosion was shown to indicate a high degree of hydrolysis, whereas less surface erosion indicated less degradation.     

Molecular and physicochemical characterisation of starches from yam,cocoyam, cassava,sweet potato and ginger produced in the Ivory Coast

Granule sizes, macromolecular features and thermal and pasting properties of starches from seven tropical sources (Florido, Kponan and Esculenta yams, cocoyam, cassava, sweet potato and ginger) were compared with those of several well‐known cereal, legume and tuber starches. The aim of the study was to characterise some non‐conventional starches with a view to possibly marketing them. Amylose content varied from 148 mg g^?1 in Esculenta starch to 354 mg g^?1 in smooth pea starch. For total starches, weight‐average molar mass (M?_w) ranged between 0.94 × 10⁸ and 1.80 × 10⁸ g mol^?1 for potato and normal maize starches respectively. Gyration radius (R?_G) varied from 157 nm for ginger starch to 209 nm for normal maize starch. Gelatinisation enthalpy (ΔH) ranged between 9.8 and 20.7 J g^?1 for wheat and Florido starches respectively. Gelatinisation peak temperature (T_g) varied from 58.1 °C for wheat starch to 87.3 °C for ginger starch. Native starch granule mean diameter ranged between 5.1 and 44.5 µm for Esculenta and potato starches respectively. Cassava and potato starches had the highest swelling power and dispersed volume fraction at all treatment temperatures, while ginger starch had the lowest. Cocoyam starch had the highest and ginger starch the lowest solubility at 85 and 95 °C. Cassava starch was the most stable under cold storage conditions. Roots and tubers such as ginger and cassava produced in the Ivory Coast are new sources of starches with very interesting properties. Thus these starches could be isolated on an industrial level in order to market them. Copyright © 2007 Society of Chemical Industry     

Behaviour of Oxidized Starches Towards Cyanoethylation

Starch of different molecular sizes brought about by oxidation of maize and rice starches were cyanoethylated under identical conditions. The degree of cyanoethylation, expressed as % N, was found to depend mainly on the molecular size of starch irrespective of its kind. As the molecular size decreases the degree of cyanoethylation increases. Cyanoethyl starches are water soluble and can be precipitated by ethanol. It was also found that the rheological properties are determined by the nitrogen content of cyanoethyl starch. When the latter acquires low nitrogen content, it exhibits non-Newtonian pseudoplastic behaviour. On the other hand, cyanoethyl starches with higher nitrogen content are characterized by non-Newtonian thixotropic. At constant rate of shear, the apparent viscosity of cyanoethyl starches is directly related to its molecular size. Storing of pastes prepared from these cyanoethyl starches for 7 d exerts considerable influence on rheological properties and apparent viscosity of these derivatives.     

The Combined Effect of Oxidation and Carbamoylethylation on the Rheological Properties of Maize and Rice Starches

The combined effect of oxidation and etherification on the molecular structure of starch was investigated. Maize and rice starches were used. Oxidation was effected using sodium hypochlorite while etherification was performed by reacting starch with acrylamide in presence of sodium hydroxide; this reaction is known as carbamoylethylation. The extent of the latter, expressed as % N, was found to increase by decreasing the molecular size of starch through oxidation. The carbamoylethyl starches so obtained could be precipitated by ethanol and they are soluble in water irrespective of the kind of starch. On the other hand, results of rheological properties indicated that they are governed mainly by the molecular size of starch. Oxidized starches with relatively high molecular size exhibit thixotropic behaviour. The degree of thixotropy decreases and changes into pseudoplasticity as the molecular size of starch decreases. The results also indicated that at constant rate of shear the apparent viscosity of carbamoylethyl starches decreases as the molecular size decreases. Furthermore, the rheological properties of carbamoylethyl starch pastes undergo considerable changes and so does the apparent viscosity when these pastes were stored for 3 days.