Phase transition of cross-linked and hydroxypropylated corn (Zea mays L.) starches

Research Progress in Modifications, Bioactivities, and Applications of Medicine and Food Homologous Plant Starch

Starchy foods are an essential part of people's daily diet. Starch is the primary substance used by plants to store carbohydrates, and it is the primary source of energy for humans and animals. In China, a variety of plants, including edible medicinal plants, such as Pueraria root, yam tuber and coix seed, are rich in starch. However, limited by their inherent properties, kudzu starch and other starches are not suitable for the modern food industry. Natural starch is frequently altered by physical, chemical, or biological means to give it superior qualities to natural starch as it frequently cannot satisfy the demands of industrial manufacturing. Therefore, the deep processing market of modified starch and its products has a great potential. This paper reviews the modification methods which can provide excellent functional, rheological, and processing characteristics for these starches that can be used to improve the physical and chemical properties, texture properties, and edible qualities. This will provide a comprehensive reference for the modification and application of starch from medicinal and edible plants.

Effect of Molar Substitution on the Properties of γ-Hydroxypropyl Starch

A new type of hydroxyalkyl starch, γ-hydroxypropyl starch (γ-HPS), was prepared by etherification of alkali-activated starch with 3-chloropropanol. The reaction efficiency, morphological change, thermodynamic and apparent viscosity properties, and other physicochemical characteristics were described. The molar substitution (MS) of modified whole starch was determined to be 0.008, 0.017, 0.053, 0.106, and 0.178, with a ratio of 5%, 15%, 25%, 35%, and 45% 3-chloropropanol to starch (v/w), respectively. Compared to native starch, the granular size and shape and the X-ray diffraction pattern of γ-HPS are not very different. For low-substituted γ-HPS, the implications may be less evident. Thermal stability measurements by means of thermogravimetric analyses and differential scanning calorimetry (TGA-DSC) proved that thermal stability was reduced and water retaining capacity was increased after hydroxypropylation. Furthermore, the findings also showed that the solubility, light transmittance, and retrogradation of γ-HPS pastes could be improved by etherification. The greater the MS of the γ-HPS, the more its freeze–thaw stability and acid resistivity increased. In this study, we provide relevant information for the application of γ-HPS in food and non-food industries.

Nutritional and functional properties changes during facultative submerged fermentation of gadung (Dioscorea hispida Dennst) tuber flour using Lactobacillus plantarum

This work aims to examine the influence of flour concentrations (5%–25% w/v), inoculum loading (2.5%–15% v/v), and fermentation time (0–144 h) on the nutritional and functional properties of gadung (Dioscorea hispida Dennst) tuber flour. The flour was microbiologically treated through facultative submerged fermentation using Lactobacillus plantarum. The carbohydrate, lipid, protein, fiber and ash contents were reduced by fermentation, while moisture content was increased. In general, the swelling power and the solubility of fermented flour were below those of the native flour. Carboxyl group content increased with fermentation time, whereas no clear trend was found for carbonyl group. The amylose content of the fermented flour was larger than that of the native flour, which most probably was due to the depolymerization of amylopectin branches to form new amylose-like molecules. The best fermentation conditions were flour concentration of 10% (w/v), inoculum loading of 5% (v/v), and fermentation for 48 h.

Surface Modification Mechanism of Cross-Linking and Acetylation, and Their Influence on Characteristics of High Amylose Corn Starch

Through dual modification of high amylose corn starch (HACS), the surface modification mechanism of cross-linking and acetylation was mainly studied, and their effect on the physicochemical properties of HACS was further investigated. The variation in surface hydroxyl numbers showed that the influence of acetylation on the structure of particles was obviously different from cross-linking. Cross-linking was carried out only on the granule surface, whereas acetylation was finished not only on the surface but also in the interior of grains. Cross-linking could unevenly produce many micropores on the particle surface. The destruction level of HACS granules caused by acetylation was greater than that of cross-linking according to XRD. The surface hydroxyl groups were not distributed evenly on HACS particles. Cross-linking did not improve the freeze-thaw stability of HACS, but acetylation could improve its freeze-thaw stability. The variation in the blue value caused by cross-linking was more than by acetylation.

PRACTICAL APPLICATION

The surface modification mechanism of cross-linking and acetylation will provide the theoretical basis for industrial production of cross-linked starch, acetylated starch, and cross-linked acetylated starch. For the surface modification, the cross-linking degree was better evaluated by the surface hydroxyl group numbers than the conventional sedimentation volume method. The development of cross-linked acetylated high amylose corn starch as a new additive will further enlarge the application of high amylose corn starch in food, textile, medicine, and so on.

Preparation of Cross-Linked High Amylose Corn-Starch and Its Effects on Self-Reinforced Starch Films

Incorporation of biodegradable self-reinforced starch composite to starch film is a promising method to improve the mechanical property of the film. In this study, cross-linked starch with different degree of cross-linking level was used as matrix to reinforce in the starch film. The thermal properties and mechanical properties of the cross-linked starch were investigated by differential scanning calorimetory (DSC), thermogravimetric analysis (TGA) and Instron tensile testing respectively. It was found that the cross-linking level greatly impact on the thermal properties of the cross-linked starch. The gelatinization temperature of starch increased with the increasing level of cross-linking modification. In addition, the cross-linking modification showed a positive effect on the mechanical properties of the starch films when the cross-linking level was controlled at a certain range.

Recent Advances in Techniques for Starch Esters and the Applications: A Review

Esterification is one of the most important methods to alter the structure of starch granules and improve its applications. Conventionally, starch esters are prepared by conventional or dual modification techniques, which have the disadvantages of being expensive, have regent overdoses, and are time-consuming. In addition, the degree of substitution (DS) is often considered as the primary factor in view of its contribution to estimate substituted groups of starch esters. In order to improve the detection accuracy and production efficiency, different detection techniques, including titration, nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analysis/infrared spectroscopy (TGA/IR) and headspace gas chromatography (HS-GC), have been developed for DS. This paper gives a comprehensive overview on the recent advances in DS analysis and starch esterification techniques. Additionally, the advantages, limitations, some perspectives on future trends of these techniques and the applications of their derivatives in the food industry are also presented.

Effect of cross-linking degree on selected properties of retrograded starch adipate

The aim of this study was to determine the effects of the concentration of paste used to produce retrograded starch, and esterification degree, on selected properties of the resultant distarch adipate. Starch paste was prepared from native potato starch (1, 4, 10, 18 or 30 g/100g), frozen, defrosted and dried. Thus produced preparations of retrograded starch were cross-linked with various doses of a cross-linking agent (0.125, 0.25, 0.5, 1.0 or 2.0 ml per 100g of starch). Properties of the produced adipates depended on both the concentration of paste used to produce retrograded starch and the degree of substitution with adipic acid residues. Solubility in water and swelling power of the cross-linked preparations of retrograded starch, as well as pasting temperature and viscosity of produced pastes, all decreased along with the increasing degree of substitution with adipic acid residues.