Impact of heat-moisture and annealing treatments on physicochemical properties and digestibility of starches from different colored sweet potato varieties

Influence of crystalline properties on starch functionalization from the perspective of various physical modifications: A review

The relationship between structural properties and functional characteristics of starch remains a hot subject among researchers. The crystalline property is a substantial characteristic of starch granules, undergoing different changes during modification techniques. These changes are closely related to the functional properties of modified starches. Physical modifications are eco-friendly techniques and are widely adopted for starch modifications. Therefore, understanding the impact of changes in crystalline properties during different physical modifications on starch functionality is the ultimate way to improve their industrial utilization. However, the existing literature still lacks the elucidation of changes in functional properties of starch in accordance with its crystalline properties during different physical treatments. Hence, this review summarizes the effects of the most important and widely used physical modifications on starch crystalline properties, highlighting the alterations in various functional properties such as hydration, pasting, gelatinization, and in vitro digestibility resulting from changes in crystalline characteristics in a single comprehensive discussion. Furthermore, the current review gives direction for envisaging the functionalization of starches based on deviations in the crystalline properties during several physical treatments.

High-Resistant Starch Based on Amylopectin Cluster via Extrusion: From the Perspective of Chain-Length Distribution and Structural Formation

Resistant starch (RS) has the advantage of reshaping gut microbiota for human metabolism and health, like glycemic control, weight loss, etc. Among them, RS3 prepared from pure starch is green and safe, but it is hard to achieve structural control. Here, we regulate the crystal structure of starch with different chain-length distributions (CLDs) via extrusion at low/high shearing levels. The change in CLDs in extruded starch was obtained, and their effects on the fine structure (Dm, dBragg, dLorentz, degree of order and double helix, degree of crystal) of RS and its physicochemical properties were investigated by SAXS, FTIR, XRD and 13C NMR analyses. The results showed that the RS content under a 250 r/min extrusion condition was the highest at 61.52%. Furthermore, the crystalline system induced by high amylopectin (amylose ≤ 4.78%) and a small amount of amylose (amylose ≥ 27.97%) was favorable for obtaining a high content of RS3-modified products under the extruding environment. The control of the moderate proportion of the A chains (DP 6-12) in the starch matrix was beneficial to the formation of RS.

Effect of microwave alone and microwave-assisted modification on the physicochemical properties of starch and its application in food

Native starch has poor stability and usually requires modification to expand its industrial application range. Commonly used methods are physical, chemical, enzymatic and compound modification. Microwave radiation, as a kind of physical method, is promising due to its uniform energy radiation, greenness, safety, non-toxicity. It can meet the demand of consumers for safe food. Microwave-assisted modification with other methods can directly or indirectly affect the structure of starch granules to obtain modified starch with high degree of substitution and low viscosity, and the modification efficiency is greatly improved. This paper reviews the effect of microwave radiation on the physicochemical properties of starch, such as granule morphology, crystallization characteristics, and gelatinization characteristics, as well as the application of microwave radiation in starch modification and starch food processing. It provides theoretical references and suggestions for the research of microwave heating modified starch and the deep processing of starchy foods.

Assessing the impact of plasma-activated water-assisted heat-moisture treatment on the extrusion-recrystallization process of hausa potato starch

The study explored the plasma-activated water (PAW)-assisted heat-moisture treatment (HMT) on the structural, physico-chemical properties, and in vitro digestibility of extrusion-recrystallized starch. Native starch of hausa potatoes underwent modification through a dual process involving PAW-assisted HMT (PHMT) followed by extrusion-recrystallization (PERH) using a twin-screw extruder. The PHMT sample showed surface roughness and etching with a significantly greater (p ≤ 0.05) RC (20.12 %) and ΔH (5.86 J/g) compared to DHMT. In contrast, PERH-induced structural damage, resulting in an irregular block structure, and altered the crystalline pattern from A to B + V-type characterized by peaks at 17.04°, 19.74°, 22°, and 23.94°. DSC analysis showed two endothermic peaks in all the extrusion-recrystallized samples, having the initial peak attributed to the melting of structured amylopectin chains and the second one linked to the melting of complexes formed during retrogradation. Dual-modified samples displayed notably increased transition temperatures (To1 74.54 and 74.17 °C, To2 122.65 and 121.49 °C), along with increased RS content (43.76 %-45.30 %). This study envisages a novel approach for RS preparation and broadens the utilization of PAW in starch modification synergistically with environmentally friendly techniques.

Structure, properties, and resistant starch content of modified rice flour prepared using dual hydrothermal treatment

In this study, modified rice flour with high resistant starch (RS) content was prepared by dual hydrothermal treatment, which combined the heat-moisture treatment with the pressure-heat treatment method. The effects of dual hydrothermal treatment on the structure and properties of modified rice flour and their relationship with RS content were further discussed. The results showed that the RS content of modified rice flour was higher than that of rice flour (RF), and dual hydrothermal treatment was more effective than single hydrothermal treatment. Adhesion and aggregation occurred between the particles of modified rice flour. Both crystallinity and short-range ordering were increased in modified rice flour compared to RF. Moreover, the modified rice flour of dual hydrothermal treatment had higher crystallinity and a more ordered short-range structure of starch, which improved RS content to a certain extent. Compared to single hydrothermal treatment, the modified rice flour of dual hydrothermal treatment had a lower viscoelasticity and a better thermal stability. Both RF and modified rice flour gels were composed mainly of free water, with minimal amounts of bound and immobile water. The study may provide a reference for the production and application of modified rice flour.

Effect of different heat-moisture treatment times on the structure, physicochemical properties and in vitro digestibility of japonica starch

Modified starch was prepared from japonica starch (JS) by heat-moisture treatments (HMT). Under the same moisture content and HMT temperature, the effects of various HMT times on the structural, properties of JS and its in vitro digestibility properties were investigated. The results showed that adhesion occurred between the particles of japonica starch after the HMT, and there were depressions on the surface. The size of the JS particles increased, the short-range ordering and relative crystallinity of the HMT-modified starch increased and gradually decreased, reaching a peak of 36.51 % at 6 h, as the HMT time was extended. The pasting indexes of HMT-modified starch decreased and then increased with the increase of the HMT time; compared with JS, the thermal stability of HMT-modified starch increased while the pasting enthalpy decreased. All the HMT-modified starches were weakly gelatinous systems and pseudoplastic fluids. Following HMT, the amount of resistant starch (RS) and slowly digested starch (SDS) grew initially before declining. The amount of RS in HMT-modified starch peaked at 24.28 % when the HMT time was 6 h. The results of this research can serve as a theoretical foundation for the creation of modified japonica starch and its use in the food industry.

Application of emerging thermal and nonthermal technologies for improving textural properties of food grains: A critical review

Emerging nonthermal and thermal food processing technologies are a better alternative to conventional thermal processing techniques because they offer high-quality, minimally processed food. Texture is important in the food industry because it encompasses several product attributes and plays a vital role in consumer acceptance. Therefore, it is imperative to analyze the extent to which these technologies influence the textural attributes of food grains. Physical forces produced by cavitation are attributed to ultrasound treatment-induced changes in the conformational and structural properties of food proteins. Pulsed electric field treatment causes polarization of starch granules, damaging the dense outer layer of starch granules and decreasing the mechanical strength of starch. Prolonged radio frequency heating results in the denaturation of proteins and gelatinization of starch, thus reducing binding tendency during cooking. Microwave energy induces rapid removal of water from the product surface, resulting in lower bulk density, low shrinkage, and a porous structure. However, evaluating the influence of these techniques on food grain texture is difficult owing to differences in their primary operation mode, operating conditions, and equipment design. To maximize the advantages of nonthermal and thermal technologies, in-depth research should be conducted on their effects on the textural properties of different food grains while ensuring the selection of appropriate operating conditions for each food grain type. This article summarizes all recent developments in these emerging processing technologies for food grains, discusses their potential applications and drawbacks, and presents prospects for future developments in food texture enhancement.

Altering structure and enzymatic resistance of high-amylose maize starch by irradiative depolymerization and annealing with palmitic acid as V-type inclusion compound

This study explored a new physical modification approach to regulate enzymatic resistance of high-amylose starch for potentially better nutritional outcomes. High-amylose maize starch (HAMS) was subjected to chain depolymerization by electron beam irradiation (EBI), followed by inducing ordered structure through annealing in palmitic acid solution (APAS). APAS treatment significantly promotes the formation of ordered structure. Starch after the combinative modification showed up to 5.2 % increase in total crystallinity and up to 1.2 % increase in V-type fraction. The EBI-APAS modification led to increased gelatinization temperature (from 66.1 to 87.6 °C) and reduced final digested percentage under in vitro stimulated digestion conditions. The moderate extent of depolymerization resulted in higher enzymatic resistance, indicating that the extent of depolymerization is crucial in EBI-APAS modification. Pearson analysis showed a significant correlation between gelatinization onset temperature and digestion kinetic parameter (k1, rate constant of fast-phase digestion). Overall, the result suggests that ordered structures of degraded molecules induced by the combinative modification contribute to the enzymatic resistance of starch. This study sheds lights on future applications of EBI-APAS approach to regulate multi-scale structures and nutritional values of high-amylose starch.

Effects of crosslinking with sodium trimetaphosphate on structural, physicochemical, rheological and in vitro digestibility properties of purple sweet potato starch

Purple sweet potato starch (PSPS) was modified using different amounts of sodium trimetaphosphate (0, 3-12%). Phosphorus content, crosslinking (CL), and substitution levels increased after modification. CL led to gradual agglomeration with each other through adhesion, compared to 0% STMP. X-ray diffraction did not change, but crystalline properties, swelling index, and peak viscosity increased, and solubility and glycaemic index decreased after crosslinking. Crosslinking increased, leading to a decrease of greater significance at 3% CL. Resistant starch was increased from 60.51 to 83.32%. G' and G'' values for crosslinking starch samples varied from 3086.00-5507.50 Pa and 513.92-800.30 Pa, respectively, after sweep test. The flow behavior index < 1 indicates that CL starch pastes are shear-thin. Positive and negative correlations were observed between gelatinized starch enthalpy and RS and between SDS and GI, respectively. The results lay the groundwork to comprehend the properties and relationships of CLPSPS and promote its possible use in foods.

Synthesis and Functions of Resistant Starch

Resistant starch (RS) has become a popular topic of research in recent years. Most scholars believe that there are 5 types of RS. However, accumulating evidence indicates that in addition to starch-lipid complexes, which are the fifth type of RS, complexes containing starch and other substances can also be generated. The physicochemical properties and physiologic functions of these complexes are worth exploring. New physiologic functions of several original RSs are constantly being discovered. Research shows that RS can provide health improvements in many patients with chronic diseases, including diabetes and obesity, and even has potential benefits for kidney disease and colorectal cancer. Moreover, RS can alter the short-chain fatty acids and microorganisms in the gut, positively regulating the body's internal environment. Despite the increase in its market demand, RS production remains limited. Upscaling RS production is thus an urgent requirement. This paper provides detailed insights into the classification, synthesis, and efficacy of RS, serving as a starting point for the future development and applications of RS based on the current status quo.

Modification of Starches and Flours by Acetylation and Its Dual Modifications: A Review of Impact on Physicochemical Properties and Their Applications

Various modification treatments have been carried out to improve the physicochemical and functional properties of various types of starch and flour. Modification by acetylation has been widely used to improve the quality and stability of starch. This review describes the effects of acetylation modification and its dual modifications on the physicochemical properties of starch/flour and their applications. Acetylation can increase swelling power, swelling volume, water/oil absorption capacity, and retrogradation stability. The dual modification of acetylation with cross-linking or hydrothermal treatment can improve the thermal stability of starch/flour. However, the results of the modifications may vary depending on the type of starch, reagents, and processing methods. Acetylated starch can be used as an encapsulant for nanoparticles, biofilms, adhesives, fat replacers, and other products with better paste stability and clarity. A comparison of various characteristics of acetylated starches and their dual modifications is expected to be a reference for developing and applying acetylated starches/flours in various fields and products.

Effects of annealing temperature and time on the structural and physicochemical properties of sweet potato flour hydrogels

The physicochemical properties of sweet potato flour (SPF) can be modified by annealing. Native SPF was annealed in deionized water at a flour-to-water ratio of 1:3 (w/v) and temperatures of 50, 55, 60, or 65 °C for either 12 or 24 h. Annealed SPF maintained the A-type crystalline region and displayed increased relative crystallinity, increased pasting temperature, and decreased breakdown. SPF gels showed enhanced hardness together with better springiness when SPF was annealed at low temperature/long time or high temperature/short time. Annealed SPF hydrogel sheets contained larger, more uniform, and smoother pores than native ones. Noticeably, hydrogel sheets made of SPF annealed at 50 °C for 24 h exhibited advanced fracture strain from 93% to 176%. Overall, this work showed that annealing could modulate the characteristics of SPR hydrogels, which may widen the extent of applications in food industries. However, the annealing conditions need to be optimized.

Starch-based controlled release fertilizers: A review

Starch, as a widely available renewable resource, has the potential to be used in the production of controlled-release fertilizers (CRFs) that support sustainable agriculture. These CRFs can be formed by incorporating nutrients through coating or absorption, or by chemically modifying the starch to enhance its ability to carry and interact with nutrients. This review examines the various methods of creating starch-based CRFs, including coating, chemical modification, and grafting with other polymers. In addition, the mechanisms of controlled release in starch-based CRFs are discussed. Overall, the potential benefits of using starch-based CRFs in terms of resource efficiency and environmental protection are highlighted.

Heat-induced amorphous aggregates assembly of soy protein modulate in vitro digestibility of potato starch

This research focused on the characteristics of amorphous aggregates derived from soy protein (SPAA), and their effects on the structural, physicochemical, and digestive properties of potato starch (PS). The SPAA induced by different heating temperatures at pH 7.0 formed an inhomogeneous spherical structure. The presence of SPAA could improve the degree of short-range order of starch, increase thermal stability, reduce pasting viscosity and breakdown, and setback viscosity values of PS. For the PS complexed with SPAAs under simulated cooking conditions, the fraction of digested starch at 300 min (C₃₀₀) decreased by 6-14 %, and rapid digestible starch content (RDS) decreased by 18-25 %, while the slowly digestible starch (SDS) and resistant starch (RS) increased by 0.4-3 % and 15-23 %, respectively. The SPAA at higher temperature treatment (SPAA₁₃₀) reduced digestive rate coefficient (k) values more significantly than SPAA at a lower temperature (SPAA₇₀, SPAA₉₀, SPAA₁₁₀). And the SPAA had no inhibitory effect on α-amylase. The results of this study would significantly contribute to expanding the theoretical information about protein regulation in starch digestion and promoting the development of healthy foods with digestion-resistant properties.

Use of maltodextrin, sweet potato flour, pectin and gelatin as wall material for microencapsulating Lactiplantibacillus plantarum by spray drying: Thermal resistance, in vitro release behavior, storage stability and physicochemical properties

Different plant products and co-products have been studied as wall materials for the microencapsulation of probiotics due to the need for new lost-cost, abundant, and natural materials. In this study, microparticles were developed by spray drying using different combinations of conventional materials such as maltodextrin, pectin, gelatin, and agar-agar with unconventional materials such as sweet potato flour to microencapsulate Lactiplantibacillus plantarum. The microparticles obtained were evaluated for encapsulation efficiency, thermal resistance, and rupture test. The most resistant microparticles were characterized and evaluated for probiotic viability during storage and survival to in vitro gastrointestinal conditions. Microparticles A (10 % maltodextrin, 5 % sweet potato flour, and 1 % pectin) and B (10 % maltodextrin, 4 % sweet potato flour, and 2 % gelatin) showed high thermal resistance (>59 %) and survival in acidic conditions (>80 %). L. plantarum in microparticles A and B remained viable with counts > 6 log CFU.g^-1 for 45 days at 8 °C and -18 °C and resisted in vitro gastrointestinal conditions after processing with counts of 8.38 and 9.10 log CFU.g^-1, respectively. Therefore, the selected microparticles have great potential for application in different products in the food industry, as they promote the protection and distribution of probiotic microorganisms.

Resistant starch from sweet potatoes: Recent advancements and applications in the food sector

In tropical and subtropical areas, tuber and root crops are staple foods and a key source of energy. Sweet potato (SP) is currently regarded as one of the world's top ten foods because of its diverse sizes, shapes, color, and health benefits. The resistant starch (RS) content of SP is substantial. It is predicted to become the cheapest item in the food industry due to its extensive variety, food stability, emulsifier and fat substitution capabilities, and as filler. As a result, interest in SP-sourced RS has recently increased. Due to their unique nutritional and functional qualities, novelty has become a popular research focus in recent years. This review will summarize the current understanding of SP starch components and their impact on the technological and physicochemical properties of produced starch for commercial viability. The importance of sweet potato RS in addressing future RS demand sustainability is emphasized. SPs are a viable alternative to tubers as a sustainable raw material for RS production. It has an advantage over tubers because of its intrinsic nutritional value and climatic endurance. Thermal, chemical, and enzymatic treatments are effective RS manufacturing procedures. The adaptability of sweet potato RS allows for a wide range of food applications.

Effects of different altitudes on the structure and properties of potato starch

The main element influencing the quality of potato starch is the environment. To investigate the effects of different altitude cultivation locations on the molecular structure and physicochemical properties of starch, two potato varieties, Jiusen No.1 B1 and Qingshu No.9 B2, were planted in three different altitude zones: A1 at low altitude (Chongzhou 450 m), A2 at middle altitude (Xichang 2800 m), and A3 at high altitude (Litang 3650 m). The results showed that the average volume, number, surface area diameter, average branched polymerization degree, crystallinity, and gelatinization temperature of two potato granules in high altitude areas were significantly lower than those in middle and low altitude areas were, and the gelatinization performance of potato starch was affected according to the correlation of starch structure characteristics. Potato starch with more short-branched chains and less long branched chains resulted in a lower gelatinization temperature in high altitude areas. The results showed that Jiusen No. 1 and Qingshu No. 9 were mainly affected by accumulated radiation and accumulated rainfall in Litang, a high altitude area, and by effective accumulated temperature in Xichang, a middle altitude area. This study quantified the influence of meteorological factors on the main starch quality of potato tubers. The results can be used as a theoretical basis for the scientific planting of high-quality potatoes.

Effects of Heat-Moisture Treatment on the Digestibility and Physicochemical Properties of Waxy and Normal Potato Starches

Heat-moisture treatment (HMT) is a safe, environmentally friendly starch modification method that reduces the digestibility of starch and changes its physicochemical properties while maintaining its granular state. Normal potato starch (NPS) and waxy potato starch (WPS) were subjected to HMT at different temperatures. Due to erosion by high-temperature water vapor, both starches developed indentations and cracks after HMT. Changes were not evident in the amylose content since the interaction between the starch molecules affected the complexation of amylose and iodine. HMT increased pasting temperature of NPS from 64.37 °C to 91.25 °C and WPS from 68.06 °C to 74.44 °C. The peak viscosity of NPS decreased from 504 BU to 105 BU and WPS decreased from 384 BU to 334 BU. The crystallinity of NPS decreased from 33.0% to 24.6% and WPS decreased from 35.4% to 29.5%. While the enthalpy values of the NPS declined from 15.74 (J/g) to 6.75 (J/g) and WPS declined from 14.68 (J/g) to 8.31 (J/g) at 120 °C. The solubility and swelling power of NPS decreased while that of WPS increased at 95 °C. Due to the lack of amylose in WPS, at the same HMT processing temperature, the reduction in peak viscosity of treated WPS compared to that of native starch was smaller than that of NPS. The resistant starch (RS) content of NPS after HMT at 120 °C was 73.0%. The slowly digestible starch (SDS) content of WPS after HMT at 110 °C was 37.6%.

A Mini Review of Physicochemical Properties of Starch and Flour by Using Hydrothermal Treatment

Starch and flour from various plants have been widely used for sundry applications, especially in the food and chemical industries. However, native starch and flour have several weaknesses, especially in functional, pasting, and physicochemical properties. The quality of native starch and flour can be improved by a modification process. The type of modification that is safe, easy, and efficient is physical modification using hydrothermal treatment techniques, including heat moisture treatment (HMT) and annealing (ANN). This review discusses the hydrothermal modifications of starch and flour, especially from various tubers and cereals. The discussion is mainly on its effect on five parameters, namely functional properties, morphology, pasting properties, crystallinity, and thermal properties. Modification of HMT and ANN, in general, can improve the functional properties, causing cracking of the granule surface, stable viscosity to heat, increasing crystallinity, and increasing gelatinization temperature. However, some modifications of starch and flour by HMT and ANN had no effect on several parameters or even had the opposite effect. The summary of the various studies reviewed can be a reference for the development of hydrothermal-modified starch and flour applications for various industries.

Effect of Pullulanase Debranching Time Combined with Autoclaving on the Structural, Physicochemical Properties, and In Vitro Digestibility of Purple Sweet Potato Starch

The effects of pullulanase debranching combined with autoclaving (PDA) at various debranching times (0 h, 5 h, 10 h, 15 h, 20 h, and 25 h) and 121 °C/20 min of autoclave treatment on the structural and physicochemical characteristics of purple sweet potato (Jinshu No.17) starch were investigated. The results indicated that the native starch (NS) was polygonal, round, and bell-shaped with smooth surfaces. After debranching treatment, the surface of the starch samples became rough and irregular. The molecular weight became smaller after treatments. X-ray diffraction C-type pattern was transformed into a B-type structure in treated samples with increased relative crystallinity. ¹³C NMR indicated an increased propensity for double helix formation and new shift at C1, 3, 5 region compared to NS. The apparent amylose content was 21.53% in the NS. As the swelling power decreased, the percentage of soluble solids increased and different thermal properties were observed. A higher yield of the resistant starch (RS) was observed in all treated starch except PDA 25 h. The findings of our study reveal that a combination of pullulanase debranching time (15 h) and autoclaving (121 °C for 20 min) is a great technique that can be used to produce a higher amount of resistant starch in the Jinshu No.17 starch.

Establishment of a quality evaluation system of sweet potato starch using multivariate statistics

Background

The quality of starch greatly affects the quality of processed products. There are many indexes for quality evaluation of starch. Currently, amylose content is considered the chief index in the quality evaluation of sweet potato starch, which is entirely based on tradition (experience) method. The existing evaluation standards lack quality evaluation standards for sweet potato starch.

Purpose

To screen reasonable evaluation indexes of sweet potato starch, and establish a scientific and systematic evaluation system of sweet potato starch.

Methods

Twenty-two components and quality indexes of sweet potato starch were measured. The evaluation indexes of sweet potato starch were screened based on a statistical description, correlation analysis, and principal component analysis (PCA), and a quality evaluation model of sweet potato starch for brewing was established based on analytic hierarchy process. The calculated values of the model were verified by linear fitting with standardized sensory evaluation values.

Results

The coefficient of variation of total starch content (%), amylose content (%), amylopectin content (%), L* value, ΔE, water absorption capacity (g/g), and pasting temperature was less than 6%, while the coefficient of variation of other indexes was larger. In addition, there were different degrees of correlation among the indexes. PCA was used to identify interrelated variables, and the first six principal components together account for 82.26% of the total variability. Then, seven core indexes — setback (cp), rate of regression (%), ratio of amylose to amylopectin (%), gel strength (kgf/cm2), a* value, ash content (%), and solubility (%) — were selected from the six principal components according to the load value of the rotation matrix. These seven core indexes replaced the original 22 indexes to simplify the evaluation of sweet potato starch. The quality evaluation model of sweet potato starch was Y = 0.034X2 + 0.321X6 + 0.141X8 + 0.08X17 + 0.023X19 + 0.08X21 + 0.321X22.

Conclusion

The comprehensive evaluation system of sweet potato starch can accurately predict the quality of sweet potato starch. The development of such a system is of great significance to the post-harvest processing of high-starch sweet potato and the breeding of high-quality and high-starch sweet potato varieties.

Effect of annealing using plasma-activated water on the structure and properties of wheat flour

In this study, wheat flour (WF) was modified by annealing (ANN) using plasma-activated water (PAW) for the first time. Compared with WF and DW-WF, the results of scanning electron microscopy (SEM) and particle-size analysis showed that the granule structure of wheat starch in PAW-WF was slightly damaged, and the particle size of PAW-WF was significantly reduced. The results of X-ray diffraction and Fourier transforming infrared spectroscopy indicated that PAW-ANN could reduce the long-range and short-range order degrees of wheat starch and change the secondary structure of the protein in WF, in which the content of random coils and α-helices was significantly increased. In addition, the analysis of solubility, viscosity, and dynamic rheological properties showed that PAW-ANN improved the solubility and gel properties of WF and decreased its viscosity properties and short-term regeneration. PAW-ANN, as a green modification technology, has the potential for further application in WF modification, as well as in the production of flour products.

Comparison of physicochemical properties and digestibility of sweet potato starch after two modifications of microwave alone and microwave-assisted L-malic acid

The effects of microwave alone (MA) and microwave-assisted L-malic acid (MLA) on the physicochemical properties, structural and digestibility of sweet potato starch were investigated. The results showed that the swelling power, lightness (L^⁎) and whiteness index (WI), gelatinization enthalpy of starch decreased by MA and MLA treatment. The starch treated by MLA showed a new characteristic absorption peak at near 1735 cm^-1 in the measurement of FT-IR, while the starch treated with MA showed no new characteristic peak. The relative crystallinity of starch modified by MSE and MA decreased, but it still retained A-type crystal structure. Scanning electron microscopy showed that the surface destruction of MSE-modified starch was greater than that of starch modified by MA. MLA increased the content of resistant starch (RS), while MA reduced the content of resistant starch (RS). The relative crystallinity and gelatinization enthalpy of continuous 60 s treatment were lower than those of discontinuous 60 s treatment. These results indicated that MLA had a greater effect on the physicochemical properties, structural and digestibility of starch than MA. Starch modified by MLA can be added to foods as a low-carbohydrate ingredient, and the starch treated by MA is suitable for foods with low swelling, such as noodles.

Sweet Potato (Ipomoea batatas L.) Phenotypes: From Agroindustry to Health Effects

Sweet potato (SP; Ipomoea batatas (L.) Lam) is an edible tuber native to America and the sixth most important food crop worldwide. China leads its production in a global market of USD 45 trillion. SP domesticated varieties differ in specific phenotypic/genotypic traits, yet all of them are rich in sugars, slow digestible/resistant starch, vitamins, minerals, bioactive proteins and lipids, carotenoids, polyphenols, ascorbic acid, alkaloids, coumarins, and saponins, in a genotype-dependent manner. Individually or synergistically, SP’s phytochemicals help to prevent many illnesses, including certain types of cancers and cardiovascular disorders. These and other topics, including the production and market diversification of raw SP and its products, and SP’s starch as a functional ingredient, are briefly discussed in this review.

Dual Modification of Sago Starch via Heat Moisture Treatment and Octenyl Succinylation to Improve Starch Hydrophobicity

To elucidate the pretreatment of a heat moisture treatment that could increase the DS and hydrophobicity of OSA starch, the effect of the moisture level of the HMT process on the physicochemical properties was investigated. The higher moisture content (MC) in the HMT process led to a decreasing degree of crystallinity and gelatinization enthalpy and also produced surface damage and cracking of the granules. HMT pretreatment with the right moisture content resulted in OSA starch with the maximum DS value and reaction efficiency. Pre-treatment HMT at 25% MC (HMT-25) followed by OSA esterification exhibited the highest DS value (0.0086) and reaction efficiency (35.86%). H25-OSA starch has been shown to have good water resistance (OAC 1.03%, WVP 4.92 × 10-5 g/s m Pa, water contact angle 88.43°), and conversely, has a high cold water solubility (8.44%). Based on FTIR, there were two new peaks at 1729 and 1568 cm-1 of the HMT-OSA starch, which proved that the hydroxyl group of the HMT starch molecule had been substituted with the carbonyl and carboxyl ester groups of OSA.

Pressure moisture treatment and hydro-thermal treatment of starch

Starch is often subjected to denaturation treatment to improve its useful properties and eliminate its shortcomings. Various methods have been developed to produce modified starches with different properties and for a variety of uses. Because physically modified starch can be produced without chemical substances or biological agents, the modification method is very simple and inexpensive, and the resulting material can be used as clean label starch. Among these physical modification technologies, heat moisture treatment (HMT) is a universally valid technology, but little is known about pressure moisture treatment (PMT)-related technology. Physical modification of starch using PMT results in new functions and value-added characteristics required by industry, and PMT has the potential to produce starch with new functions. In this paper, PMT-related technologies for physically modified starch, the difference between PMT and the hydro-thermal treatment, and clean label starch manufacturing using HMT and PMT were investigated.

Rhizophagus irregularis and Nitrogen Fixing Azotobacter Enhances Greater Yam (Dioscorea alata) Biochemical Profile and Upholds Yield under Reduced Fertilization

Greater yam (Dioscorea alata L.) is a tropical plant with a large food reserve in its underground tubers. Cultivating the greater yam is considered an essential food security crop. Yam tuber yield and quality is decreased by poor soil fertility, heavy use of fertilizers and attack of insect pest. The heavy use of fertilizers impaired the soil structure polluted the environment, and adversely impacted human beings. We employed Rhizophagus irregularis (Arbuscular Mycorrhiza Fungus) and nitrogen fixing Azotobacter to help reduce the adverse effects of fertilisers on the plants. In this study, we applied five treatments such as (1) CF: normal with conventional package and practices, (2) 70%CF: 70% chemical fertilizer, (3) 70 %CF + RI: 70% CF + AMF (R. irregularis), (4) 70%CF + AC: 70% CF + PGPB (Azotobacter chroococum), and (5) 70%CF + RI + AC: 70% CF + R. irregularis + Azotobacter chroococum, as donated as T1, T2, T3, T4 and T5, obtained that 70%CF + RI + AC was found to be the most efficient treatment under reduce chemical fertilization for improving morphological traits and biochemical content of greater yam. Although some other treatments such as 70%CF + AC, 70%CF + RI, 70% CF and CF demonstrated considerable effects in yam compared with 70%CF: 70% chemical fertilizer.

Effect of freezing-assisted treatment on the formation of stable VII -type complex of fried sweet potato starch and its mechanism

To comprehensively understand the effect of freezing-assisted treatment on the physicochemical properties of the fried sweet potato starch, the structural changes at granular and crystalline level were investigated. The results suggested that the freezing temperature exerted a significant effect on the interactions between sweet potato starch (SPS) and fried oil. With decreasing the freezing-assisted temperature, the gelatinization enthalpy of the fried frozen SPS remarkably increased by 1.5-4.9 J·g^-1 and the transition temperatures of the second peak were elevated from 132.5°C to 136.5-141.1°C compared to that of native SPS, which suggested that more stable V_II -type starch-lipid complexes were formed during frying. This finding was consistent with the results of the X-ray diffractometer that the intensity of the diffraction peak at 20.1° for V-type complex increased sharply as the temperature decreased from 20°C to -80°C, and the corresponding relative crystallinity and R_1047/1022 values were increased from 16.5% and 0.35 to 26.4% and 0.45, respectively. The scanning electron microscopy revealed that the lower freezing-assisted temperature before frying promoted a membrane-like material covered on surfaces. The results showed that decreasing the freezing temperature promoted the formation of stable V_II -type complex during frying. PRACTICAL APPLICATION: The purpose of this study was to comprehensively understand the effect of freezing-assisted treatment on the physicochemical properties of the fried sweet potato starch. These results provided useful information and effective method for producing fried starch-based foods with low digestibility.

Modification in physicochemical, structural and digestive properties of pea starch during heat-moisture process assisted by pre- and post-treatment of ultrasound

Ultrasound is increasingly used for physicochemical modification of food systems as a green technology. Effects of heat-moisture treatment (HMT) assisted by pre- and post-treatment of ultrasound on physicochemical, structural and digestive properties of pea starch was investigated. Pea starch maintained the original morphology and C-type of crystalline after ultrasound treatment (UT), but 4 h or more of HMT and HMT assisted by UT changed the crystalline from C-type to A-type. All treatments decreased the crystallinity, molecular weight, swelling power and solubility at 70-90 °C, and elevated the content of resistant starch. Moreover, HMT assisted by pretreatment of UT was found to increase the viscosity and high-temperature stability of starch paste compared with others by the orderly combined effect of UT-induced depolymerization and HMT-induced depolymerization and rearrangement of starch chains. These results may promote the appropriate use of ultrasound in food industries and the production of starch materials for potential applications.