Characterization of starches isolated from Mexican pulse crops: Structural, physicochemical, and rheological properties

This work aimed to characterize and compare the physicochemical properties of four pulse starches: bean, chickpea, lentil, and pea. Chemical proximate analysis, elemental composition, morphological grain characterization, crystalline structure, thermal analysis, FTIR analysis, and pasting properties were conducted. The proximate analysis shows that these starches have low fat, mineral, and protein content but high amylose values ranging from 29 to 36 % determined by colorimetry. Despite the high amylose content, the starches did not exhibit the typical behavior of an amylose-rich starch, with high peak viscosity and low breakdown and setback. It was found that this behavior was likely due to the large granule size of the ellipsoidal, spherical, and kidney-shaped granules and the high content of some minerals such as Na, Mg, K, Fe, Mn, P, and Si. The study also found that all pulse starches simultaneously contain monoclinic and hexagonal crystals, making them C-type starches. The findings were verified through the Rietveld analyses of X-ray diffraction patterns and differential scanning calorimetry, in which bimodal endothermic peaks evidenced both types of crystals being gelatinized.

Identification of a novel starch-converting GtfB enzyme from the Fructilactobacillus sanfranciscensis TMW11304 to reduce the viscoelasticity and retrogradation of tapioca starch

Starch-converting α-glucanotransferases are efficient enzymatic toolkits for the biosynthesis of diverse α-glucans, which hold vast application potential in the food industry. In this work, we identified a novel GtfB protein from Fructilactobacillus sanfranciscensis TMW11304 (FsTMW11304 GtfB) in NCBI. Although this enzyme was highly conserved in motifs I-IV with those isomalto-maltopolysaccharides (IMMPs)-producing GtfB α-glucanotransferases, it possessed distinct deletions and mutations in two crucial loops shaping the active site. Hence, unlike those GtfB enzymes, FsTMW11304 GtfB not only exhibited excellent 4,6-α-glucanotransferase activity on amylose to generate atypically low-molecular-weight IMMPs with consecutive linear (α1 → 6) linkages up to 48 %, but also held good capability towards branched substrates. Besides, compared with the control, the treatment by FsTMW11304 GtfB reduced the storage/loss modulus of granular and gelatinized tapioca starches (TS) by 12.0 %/17.9 % and 91.4 %/82.9 %, respectively, indicating that the rigidity of the gel structure was attenuated to different degrees in the two reaction systems. Furthermore, the setback viscosity observed in the gelatinized TS modified by FsTMW11304 GtfB was only 5 % of that observed in the control group, suggesting the short-term anti-retrogradation property has been substantially improved. Thus, FsTMW11304 GtfB represents a meaningful addition to the α-glucanotransferases in GH70 family, which expands the repertoire of diverse α-glucans synthesized from starch and facilitates the understanding of the structure-function relationship of the GtfB α-glucanotransferases.

Insights into the hierarchical structure and physicochemical properties of starch isolated from fermented dough

Understanding the hierarchical structure and physicochemical properties of starch isolated from fermented dough with different times (0-120 min) is valuable for improving the quality of fermented dough-based products. The results indicate that fermentation disrupted the starch granule surface and decreased the average particle size from 19.72 μm to 18.45 μm. Short-term fermentation (< 60 min) disrupted the crystalline, lamellar, short-range ordered molecular and helical structures of starch, while long-term fermentation (60-120 min) elevated the ordered degree of these structures. For example, relative crystallinity and double helix contents increased from 23.7 % to 26.8 % and 34.4 % to 37.2 %, respectively. During short-term fermentation, the structural amorphization facilitated interactions between starch molecular chains and water molecules, which increased the peak viscosity from 275.4 to 320.6 mPa·s and the swelling power from 7.99 to 8.52 g/g. In contrast, starches extracted from long-term fermented dough displayed the opposite results. Interestingly, the hardness and springiness of starch gels gradually decreased as fermentation time increased. These findings extend our understanding of the starch structure-property relationship during varied fermentation stages, potentially benefiting the production of better-fermented foods.

Impact of ultrasound treatment on the physicochemical and rheological properties of acid hydrolyzed sorghum starch

The present study aimed to evaluate the influence of ultrasonication on the physicochemical properties of native and acid-hydrolyzed white sorghum starch. Sorghum starch exhibited improved freeze-thaw stability, solubility, swelling power, and paste clarity after mild sonication. Starches sonicated at 30 % amplitude for 10 and 20 min increased the peak viscosity to 249 and 240 BU, gel firmness to 140.23 and 131.62 (g), ΔH to 13.4 and 13.1 (J/g), crystallinity to 29.51 and 29.10 (%), double helix content to 1.11 and 1.07 and degree of ordered structures to 1.16 and 1.09. The sonicated dual-treated samples (sonicated-acid hydrolyzed) exhibited reduced swelling power, peak viscosity, gelatinization temperatures and gel firmness. In contrast, the solubility, paste clarity, ΔH, percentage of crystallinity, double helix content and degree of ordered structures improved. Ultrasonic treatment made cracks and holes in the granule surface, whereas dual-treated starches were more porous and rougher, with deep depressions. All sorghum starches displayed shear-thinning behavior (n < 1). The pseudoplastic behavior and consistency indices of the starch paste decreased with increasing sonication time and amplitude. The G' was always higher than G" and tanδ was <1 for all samples, indicating a more solid/elastic behavior. The increased sonication time and amplitude, as well as the dual-treatment, caused the gel to become more susceptible to shear forces, which resulted in a decrease in G' and G" and an increase in tanδ.

Effect of addition of methionine and histidine on physicochemical and rheological characteristics of water chestnut starch as revealed by molecular dynamic simulations

The effect of addition of amino acids including methionine (Met) and histidine (His) at selected concentrations (2, 6, 10, and 15%) on the physicochemical, pasting, and rheological properties of water chestnut starch (WS) was evaluated. A higher quantity of amino acids considerably (p < 0.05) inhibited the ability of starch-amino acid blends to expand their solubility index and swelling capacity. The addition of amino acids also significantly decreased peak viscosity (952.33-540.67 cP), hot paste viscosity (917-528 cP), cold paste viscosity (1209.67-659 cP), and setback (277.67-131 cP) of WS. Addition of amino acids enhanced the stability ratio (SR) of WS. All the studied samples displayed storage moduli (G') values higher than loss moduli (G'') but rheologically weak gel characteristics. Molecular dynamics simulation studies revealed that interactions between amino acids and water greatly reduced the number of starch-water hydrogen bonds while preserving a higher number of starch-starch intramolecular interactions. This study could provide important insights for better understanding of modification of water chestnut starch functionality under the influence of amino acid residues.

The impact of different concentrations of hyaluronic acid on the pasting and microstructural properties of corn starch

Starch aging in starchy foods is a major problem affecting their quality. In order to improve the viscosity and textural properties of native starch gelatinization and retrogradation, this study investigated the effect of hyaluronic acid (HA) at different concentrations (2 %, 4 %, 6 % w/w) on the pasting and microstructure of corn starch (CS). The findings revealed that the addition of HA significantly enhanced the peak viscosity, solubility, and water-holding capacity of the CS-HA mixtures. Moreover, it reduced the pasting temperature, swelling force, and leaching of amylose. All the mixtures exhibited shear thinning and thixotropic properties. The CS-HA mixtures created a thicker pseudoplastic system with significantly enhanced shear stability. The structures of the mixtures were characterized using Fourier transform infrared spectroscopy and scanning electron microscopy. It was observed that HA effectively inhibited short-term retrogradation of starch, enhanced the interaction between CS and HA, and formed a dense honeycomb three-dimensional mesh structure. In conclusion, as a novel anionic hydrocolloid, HA holds great potential to improve the retrogradation properties of starch-based products.

Effects of sugar beet pectin on the pasting, rheological, thermal, and microstructural properties of wheat starch

The effects of addition of sugar beet pectin (SBP) on the pasting, rheological, thermal, and microstructural properties of wheat starch (WS) were investigated. Results revealed that SBP addition significantly increased the peak viscosity, trough viscosity, breakdown value, final viscosity, and setback value of WS, whereas decreased the pasting temperature. SBP raised the swelling power (from 13.44 to 21.32 g/g) and endothermic enthalpy (ΔH, from 8.17 to 8.98 J/g), but decreased the transparency (from 9.70 % to 1.37 %). Regarding rheological properties, WS-SBP mixtures exhibited a pseudo-plastic behavior, and SBP enhanced the viscoelasticity, but decreased the deformability. Particle size distribution analysis confirmed that SBP promoted the swelling of WS granules. Fourier-transform infrared spectroscopy results suggested that the interactions between SBP and WS did not involve covalent bonding, and the formation of ordered structure was inhibited by SBP addition. Additionally, scanning electron microscopy observation found that the gel network of WS-SBP mixtures became more irregular, pore size gradually decreased, and the wall became thinner as the SBP concentration increased. These results indicated that SBP is a promising non-starch polysaccharide that can enhance the processing properties of WS.

Influence of oxidation, acetylation and hydrothermal treatment on structure and functionality of common buckwheat starch

The set aim of present work was to investigate the effects of acetylation, oxidation and heat moisture treatment on physicochemical, pasting, gel texture, structural, thermal and morphological properties of common buckwheat starch. Swelling power and solubility of starches reduced after modification except acetylation. Color of buckwheat starch improved after oxidation and acetylation. Paste clarity increased while syneresis reduced following modification with the exception of oxidation. Pasting properties of buckwheat starch revealed increased peak viscosity and breakdown viscosity following modification treatments. Gel texture analysis depicted increased hardness and reduced springiness, chewiness and cohesiveness for modified starches of buckwheat. Diffractograms of starches showed variation in intensity of some bands. Heat moisture treatment increased agglomeration and oxidation caused slight depression on surface of some granules. Relative crystallinity reduced following oxidation and hydrothermal treatment of starch. The gelatinization temperatures were increased in hydrothermal treated starch samples while oxidation and acetylation reduced the gelatinization temperature. The findings of this work would favor the new applications of modified starch from common buckwheat.

Lotus starch/bamboo shoot polysaccharide composite system treated via ultrasound: Pasting, gelling properties and multiscale structure

This study investigated the effects of ultrasound treatment on the physicochemical properties, digestion properties, and multiscale structure of a lotus root starch (LS) and bamboo shoot polysaccharide (BSP) composite system. It also preliminarily revealed the mechanism underlying the modification effect of ultrasound treatment. After 180-360 W ultrasound treatment, the viscosity, thixotropy, and gel viscoelasticity of the LS/BSP paste increased. However, treatment with the ultrasound power of 540 and 720 W decreased viscoelasticity. After 14 days of retrogradation, the hardness and cohesiveness of the LS/BSP gel increased under 180 and 360 W ultrasound treatment but decreased under 540 and 720 W ultrasound treatment. After 540 W ultrasound treatment, RDS content decreased by 17.2 % and resistant starch content increased by 32.5 %. After 180 min of in vitro digestion, the hydrolysis rate of LS/BSP decreased from 97.82 % to 93.13 % as the ultrasound power increased to 540 W. Ultrasound promoted the uniform dispersion of BSP in the starch paste and the movement, orientation, rearrangement, and aggregation of starch and BSP molecular chains. These effects further enhanced the interaction between BSP and starch, resulting in the formation of a dense paste structure with strong resistance to digestive enzymes. This work revealed the mechanism of the effects of ultrasound treatment on LS/BSP and found that 360-540 W ultrasound treatment could improve the physicochemical properties and digestion properties of LS/BSP.

Nutritional quality and physicochemical properties of biscuit from composite flour of wheat, African yam bean and tigernut

This study investigated the effect of the supplementation of wheat flour with flour blends of African yam bean (AYB) and tigernut for the production of biscuits and evaluated the sensory characteristics. The composite flours were of ratio 70:25:5 (TWB), 70:20:10 (ATW), 70:15:15 (BTT) for wheat: AYB: tigernut, respectively, while 100 % wheat flour served as control (WTY). The composite flour samples were analyzed for proximate, functional and pasting properties. The physical and chemical properties and sensory attributes of the developed biscuits were carried out. The moisture, protein, fat, ash, crude fiber, carbohydrate, and energy contents of the composite flour ranged from 6.63 to 8.13 %, 11.22-18.36 %, 13.27-19.15 %, 0.98-0.99 %, 3.96-7.43 %, 59.97-62.55 % and 400.89 to 410.40 Kcal/100g, respectively. The results showed that protein fat, ash and crude fiber of the biscuit were improved. The water and oil absorption capacity of composite flour was low while the pasting properties of the composite flour blends reduced as the AYB flour increased. All the composite flour blend biscuit samples possessed high essential nutrients and antioxidant potential. All the biscuits samples were accepted by the panelists, however, sample BTT (70 % wheat flour+15 % AYB flour+ 15 % tigernut flour) was most accepted in appearance, aroma, taste, crispness and overall acceptability. Therefore, biscuits from the flour blends of wheat, AYB and tigernut could be nutritionally beneficial and good for adults.

Effects of Qingke β-glucan with different molecular weights on pasting, gelation, and digestive properties of rice starch

This study aimed to investigate the impact of Qingke β-glucan (QBG) concentrations and molecular weights (MWs) on rice starch (RS). With the increasing concentrations and MWs, the pasting properties and gelatinization enthalpy of RS/QBG suspension decreasing was observed by using rheometer and differential thermal scanning analysis, respectively, which was consistent with the results of X-ray diffraction. In Infrared spectrum, QBG combined with leached amylose via hydrogen bonds, thus preventing the reaggregation of RS particles and inhibiting the short-term retrogradation of RS. The results of scanning electron microscopy and confocal laser scanning microscopy suggested that interaction between QBG and RS changed RS microstructure, reduced the leached amylose of the starch, and thus altered RS/QBG digestibility that the digestion rate of RS/QBG decreased with the incrementing QBG MWs at in vitro simulated experiments. These results provide further understanding and expand potential application to starch-based foods.

Understanding the multi-scale structure and physicochemical properties of millet starch with varied amylose content

The multi-scale structure and physicochemical properties of starch from five indigenous millet varieties were investigated and their correlations were revealed. Results showed that apparent amylose content (AAC) ranged from 12.3% to 27.4%, and as the amylose increasing, the ordered degree of starch double-helical, ordered molecular structure and crystalline structures displayed a declined trend. All millet starches showed polygonal, spherical or irregular shapes varied with size, but XIN-3 starch granules (highest AAC) presented higher granule rigidity, compactness and bulk intensity. Specifically, the ordered molecular structure (e.g., higher double-helix content, short-range ordered degree and relative crystallinity) of millet starch with low amylose limited the swelling degree of starch granules and in turn decreased the characteristic viscosity. However, rapidly digestible starch (RDS) was significantly negatively correlated with AAC and ordered molecular structure. The information obtained in this study would be significant in the rational utilization of these millet starches in food industry fields.

Cultivation pattern affects starch structure and physicochemical properties of yam (Dioscorea persimilis)

Yam (Dioscorea spp.) is a major food source in many countries due to its tuber rich in starch (60 %-89 % of the dry weight) and various important micronutrients. Orientation Supergene Cultivation (OSC) pattern is a simple and efficient cultivation mode developed in China in recent years. However, little is known about its effect on yam tuber starch. In this study, the starchy tuber yield, starch structure and physicochemical properties were compared and analyzed in detail between OSC and Traditional Vertical Cultivation (TVC) with Dioscorea persimilis "zhugaoshu", a widely cultivated variety. The results proved that OSC significantly increased tuber yield (23.76 %-31.86 %) and commodity quality (more smooth skin) compared with TVC in three consecutive years of field experiments. Moreover, OSC increased amylopectin content, resistant starch content, granule average diameter and average degree of crystallinity by 2.7 %, 5.8 %, 14.7 % and 9.5 %, respectively, while OSC decreased starch molecular weight (Mw). These traits resulted in starch with lower thermal properties (To, Tp, Tc, ΔH_gel), but higher pasting properties (PV, TV). Our results indicated that cultivation pattern affected the yam production and starch physicochemical properties. It would not only provide a practical basis for OSC promotion, but also provide valuable information on how to guide the yam starch end use in food and non-food industries.

Effect of heat-moisture treatment on the physicochemical properties and digestibility of proso millet flour and starch

Proso millet flour (PMF) and starch (PMS) were subjected to heat-moisture treatment (HMT) at 25 % moisture content and 110 °C for 4 h. The effects of HMT on physicochemical and structural properties and in vitro digestibility of PMF and PMS were analyzed. After HMT, SEM showed aggregation and damage to the surface of starch granules, while CLSM showed proteins wrapped around the granules. The amylopectin chain length distribution (CLD) remained unchanged in PMF and PMS after HMT, indicating intact covalent bonds between glucose units. HMT decreased the swelling power, solubility, viscosity of the paste, and gelatinization enthalpy and increased the pasting temperature and gelatinization temperature of PMF and PMS. HMT changed the XRD pattern of PMF from A to A + V type starches, whereas that of PMS remained unchanged. FTIR study showed an increase in the degree of short-range molecular order of PMF and PMS after HMT. In vitro digestibility evaluation showed that the rapidly (RDS) and slowly digestible starch (SDS) contents of PMF and PMS increased, whereas the resistant starch (RS) content decreased after HMT. HMT flour and starch have suitable properties for use in a wide range of food products, from canned to frozen, as well as non-food products.

Complexation between rice starch and cellulose nanocrystal from black tea residues: Gelatinization properties and digestibility in vitro

In this work, cellulose nanocrystal (CNC) was extracted from black tea waste and its effects on the physicochemical properties of rice starch were explored. It was revealed that CNC improved the viscosity of starch during pasting and inhibited its short-term retrogradation. The addition of CNC changed the gelatinization enthalpy and improved the shear resistance, viscoelasticity, and short-range ordering of starch paste, which meant that CNC made the starch paste system more stable. The interaction of CNC with starch was analyzed using quantum chemistry methods, and it was demonstrated that the hydrogen bonds were formed between starch molecules and the hydroxyl groups of CNC. In addition, the digestibility of starch gels containing CNC was significantly decreased because CNC could dissociate and act as an inhibitor of amylase. This study further expanded the understanding of the interactions between CNC and starch during processing, which could provide a reference for the application of CNC in starch-based foods and the development of functional foods with a low glycemic index.

Ozone exposure tunes the physicochemical properties of sweet potato starch by modifying its molecular structure

Ozonation is an efficient method for improving the technical performance of some starches, but the feasibility of its use for sweet potato starch remains unknown. The effects of aqueous ozonation on the multi-scale structure and physicochemical properties of sweet potato starch were explored. Structurally, ozonation did not generate significant alterations at the granular level (size, morphology, lamellar structure, and long-range and short-range ordered structures), but led to tremendous changes at the molecular level, including converting hydroxyl groups to carbonyl and carboxyl groups and depolymerizing starch molecules. These structural changes resulted in prominent alternations in the technological performance of sweet potato starch, such as increases in water solubility and paste clarity and decreases in water absorption capacity, paste viscosity, and paste viscoelasticity. For these traits, their amplitudes of variation elevated when the ozonation time was extended and peaked at the longest ozonation time (60 min). The greatest changes in paste setback (30 min), gel hardness (30 min), and the puffing capacity of the dried starch gel (45 min) were observed at moderate ozonation times. In summary, aqueous ozonation is a new method for fabricating sweet potato starch with improved functionality.

Modification of the microstructure of tef [Eragrostis tef (Zucc.) Trotter] flour ultrasonicated at different temperatures. Impact on its techno-functional and rheological properties

Tef flour comes from a nutritionally-rich ancient grain gaining increasing interest in gluten-free market. Gluten-free sources are modified by different means to improve their functionality. Ultrasound treatment (US) alters flours' structure and leads to physically modified flours with a wider application range. The aim of the present work was to evaluate the impact of US treatments of moderate treatment time, 10 min, and high concentration of the aqueous flour dispersion, 25%, on the microstructural, starch damage, apparent amylose content, techno-functional, pasting and rheological properties of two tef flour varieties, white and brown. Temperature was varied (20, 40, 45, 50, and 55 °C) to modulate the impact of sonication. US treatments led to general particle fragmentation which markedly increased starch damage and lightness (L*) values. Apparent amylose content was higher after ultrasonication, as consequence of molecular fragmentation due to cavitation. Increased starch granules' exposed area led to enhanced interaction with water, promoting the water absorption index (WAI) and swelling power (SP) of treated flours. Pasting properties showed increased pasting temperatures as well as decreased viscometric profiles with lower breakdown viscosities, indicative of starch rearrangement improved by increasing temperature. Rheological properties indicated higher consistency in gels after US treatments, with improved ability to withstand stress and lower values of tan(δ)1 reflecting a higher solid-like behavior and higher strength of the gel. Temperature was found to be a crucial variable during US treatments, showing an improved degree of modification at higher temperatures in ultrasonicated tef flours, following the same trend in both varieties.

Genome-wide association study of quality traits and starch pasting properties of maize kernels

BACKGROUND

Starch are the main nutritional components of maize (Zea mays L.), and starch pasting properties are widely used as essential indicators for quality estimation. Based on the previous studies, various genes related to pasting properties have been identified in maize. However, the loci underlying variations in starch pasting properties in maize inbred lines remain to be identified.

RESULTS

To investigate the genetic architecture of these traits, the starch pasting properties were examined based on 292 maize inbred lines, which were genotyped with the MaizeSNP50 BeadChip composed of 55,126 evenly spaced, random SNPs. A genome-wide association study (GWAS) implemented in the software package FarmCPU was employed to identify genomic loci for the starch pasting properties. 48 SNPs were found to be associated with pasting properties. Moreover, 37 candidate genes were correlated with pasting properties. Among the candidate genes, GRMZM2G143646 and GRMZM2G166407 were associated with breakdown and final viscosity significantly, and both genes encode PPR (Pentatricopeptide repeat) protein. We used GWAS to explore candidate genes of maize starch pasting properties in this study. The identified candidate genes will be useful for further understanding of the genetic architecture of starch pasting properties in maize.

CONCLUSION

This study showed a complex regulation network about maize quality trait and starch pasting properties. It may provide some useful markers for marker assisted selection and a basis for cloning the genes behind these SNPs.

Low temperature and light combined stress after heading on starch fine structure and physicochemical properties of late-season indica rice with different grain quality in southern China

Late-season indica rice frequently encounters low temperature (LT) along with low light (LL) after heading in southern China, which deteriorates the grain quality by altering starch quality. However, the detailed effects on starch properties of these stressors remain unclear. Herein, two indica rice cultivars with good and poor grain quality were grown under control (CK), LT, and LT + LL conditions after heading and the structural and physicochemical properties of their starch were evaluated. Compared with CK, LT and LT + LL worsened thermal and pasting properties of starch in the two cultivars, mainly because they increased branch chain branching and A chain (DP ≤12), and decreased average branch chain length and crystallinity. Compared with LT, LT + LL deteriorated the pasting properties of the poor-quality cultivar, such as reducing breakdown (BD), final and peak viscosity, which mainly owing to decreasing the starch branching and crystallinity degrees, and increasing the small starch granules (d < 10 μm). Gelatinization enthalpy and BD both had significant and positive correlations with amylose content, the ratio of amylose and amylopectin, B3 chain and crystallinity. Taken together, these results suggest that LT and LT + LL during grain filling can deteriorate the physicochemical properties of starch in late-season indica rice cultivars by disrupting starch multilevel structure, especially upon LT + LL. In particular, while poor-quality cultivar had poorer physicochemical properties, the good-quality cultivar had poorer thermal properties under LT + LL.

Structural, physicochemical and rheological properties of starches isolated from banana varieties (Musa spp.)

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High starch content in green banana can be extracted for industry and avoid waste.

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Banana starch from Tanzania was rich in amylose and resistant starch.

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Banana starch paste presented great structural stability.

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Banana starch had potential to produce edible films and replace chemical binder.

Banana starches were isolated from five banana varieties in Tanzania to analyze the proximate composition, structure, physicochemical and rheological properties. The amylose content of banana starches was 29.92 ± 0.17 %–39.50 ± 0.08 % and the resistant starch content of cooked banana starches ranged from 44.74 ± 1.72 % to 55.43 ± 1.52 %. Banana starch granules presented irregular shapes with particle size of 21.73 to 24.67 μm and showed B-type or C-type crystalline patterns with crystallinity of 36.69 % to 41.83 %. The solubility and the swelling power were 2.5 ± 0.42 %–4.4 ± 0.57 % and 11.27 ± 0.04 %–12.48 ± 0.71 %, respectively. Mzuzu and Malindi starches possessed lower gelatinization temperature. The high gelatinization peak viscosity (2248 ± 67–2897 ± 71 cP), low breakdown (556 ± 7–960 ± 41 cP) and low setback (583 ± 29–864 ± 118 cP) indicated banana starch could replace chemically cross-linked starch for applications that require stable viscosity. The rheological analysis showed that banana starches exhibited shear thinning behavior and had great processing adaptability. The results all above will provide basic data for the development and utilization of banana starch.

Physical modification of maize starch by gelatinizations and cold storage

The effects of gelatinization at three selected temperatures (DSC characteristic peaks temperature: TO, TP, and TC) and subsequent cold storage (CS) treatment on structural characteristics, pasting, and rheological properties of maize starch (MS) were investigated. The pasting, rheological properties of MS was changed with the increase of gelatinization temperature from TO to TC, but were not further significantly changed if the gelatinization temperature was higher than TC. Pasting and thermal properties analysis suggested that gelatinization at TC (TC treatment) significantly increased the gelatinization and pasting temperature of MS. Moreover, TC treatment decreased breakdown viscosity by 8.49 times and setback viscosity by 2.53 times. Dynamic rheological measurements revealed that the TC treatment caused the lower G' and G" of MS, and decreased the thickening coefficient by 55.17 %. These results indicated that TC treatment could enhance the thermal stability properties of MS, inhibiting the shear and short-term retrogradation, the shear-thinning behavior of MS. Interestingly, the CS treatment further inhibited the shear and short-term retrogradation and the shear-thinning behavior of MS. The leaked starch molecules aggregate to form a harder structure after gelatinization and starch molecules were further aggregated after CS treatment, these all were hypothesized to be responsible for these results.

Rice starch multi-level structure and functional relationships

Starch from 15 different rice genotypes with amylose content (AC) ranging 1.5%-30.6% were investigated for relationships between structures and properties. For parameters related to the granular level, the most important relationships were found for AC, average chain lengths (ACL) of the amylopectin (AP) fb₁ chains having a length of DP 13-24, crystallinity, and the thickness of the crystalline (d_c) and the amorphous lamellae (d_a) of the starch granule. AC and d_c were negatively correlated with the peak gelatinization temperature (T_p), thermal enthalpy (ΔH), and peak viscosity (PV), but positively correlated with swelling power. ACL_fb1 and d_a, as compared to AC and d_c, had the opposite effects on these parameters, demonstrating important roles of specific molecular and lamellar structures on the starch granular stability. For the gelatinized systems, increasing ACL_fb1 decreased retrogradation, while AC increased retrogradation by increasing the resistant starch (RS) content, storage modulus (G'), and setback (SB).

Development changes in multi-scale structure and functional properties of waxy corn starch at different stages of kernel growth

Waxy corn starch is widely used in food and papermaking industries due to its unique properties. In this work, the structural and functional properties of starch isolated from waxy corn at different stages of kernel growth were investigated and their relationships were clarified. The results showed that with kernel growth, the surface of starch granules became smooth gradually, and the inner growth rings and the porous structure grew and became clear. Meanwhile, the weight-average molecular mass (M_w), root mean square radius (R_g), and average particle size increased while the amylose content decreased, which should account for the decreased pasting temperature (from 71.37 to 67.44 °C) and increased peak viscosity (1574.2 to 1883.1 cp) and breakdown value observed. Besides, the contents of slowly digestible starch (SDS) and resistant starch (RS) in waxy corn starch decreased significantly (from 44.01% to 40.88% and from 16.73% to 9.80%, respectively, p < 0.05) due to decreases in the double helix content, crystallinity, and structural order, and increases in the semi-crystalline lamellae thickness and the amorphous content. This research provides basic data for the rational utilization of waxy corn starch at different stages of kernel growth.

Infrared heating under optimized conditions enhanced the pasting and swelling behaviour of cowpea starch

Native starches are not suitable for industrial use and must be modified for improved functionality. In this study, the effect of moisture preconditioning and infrared heating time on physicochemical properties of cowpea starch was investigated using a two-factor central composite rotatable design. Factors (moisture levels:10-40 g/100 g starch and infrared heating time:10-60 min) with their corresponding α mid-point values resulted in 13 experimental runs. Selected functional and pasting properties were determined as response variables. Starch samples produced under optimized conditions were compared with corn starch and their physicochemical properties determined. Except for pasting temperature, cowpea starch prepared using the optimal conditions (moisture: 46.21 g/100 g starch, dry basis and heating time of 32.88 min) had higher functional and pasting properties compared with the native cowpea starch. Infrared heating significantly reduced the gelatinization temperatures of cowpea starch but did not significantly change that of the corn starch. The crystallinity and double-helical order structure of moisture conditioned cowpea starch also reduced after modification. Cowpea starch showed a bigger granule size, higher swelling power but lower water absorption capacities and pasting properties compared with the control. The infrared heating process is a novel and promising modification method for improving the swelling properties of starch.

Structural characteristics of tamarind seed polysaccharides treated by high-pressure homogenization and their effects on physicochemical properties of corn starch

In this work, structural characteristics of TSPs treated by high-pressure homogenization (HPH) and their effects on physicochemical properties of corn starch were analyzed. HPH induced monosaccharides change, Gal/Glc ratio decrease from 0.32 to 0.25, and molecular weight (M_w) decrease from 10.55 to 4.47 × 10⁵ Da through damaging glycosidic linkages in the backbone and side-chain of TSPs. Furthermore, 90 MPa homogenized TSP (higher Gal removal) showed inhibitory effects on starch paste retrogradation, and TSPs with a lower M_w (homogenized at 60 and 90 MPa) could limit water precipitation during the long-term storage. Moreover, M_w and Gal/Glc ratio were the major factors for the determined effects of TSPs on physicochemical properties of corn starch. The results could provide new insights into the relationship between TSP structure and their effects on the physicochemical properties of starch.

Impact of Extrusion Temperature on In Vitro Digestibility and Pasting Properties of Pea Flour

Pea flour was extruded at 50, 70, and 90 °C. The in vitro digestibility and characteristics of native and extruded pea flour were investigated. The in vitro starch digestibility (IVSD) and in vitro protein digestibility (IVPD) of the extruded pea flour were higher than those of the native pea flour and increased with increasing extrusion temperature from 50 to 90 °C. The rapidly digestible starch increased to 28.34% at 90 °C, the highest slowly digestible starch (SDS) content was 22.70% at 50 °C, and resistant starch content decreased to 4.71% at 90 °C. The IVPD increased from 80.94% relative to the native pea flour to 90.21% at 90 °C. Improved swelling power enabled the extruded pea flour to exhibit better performance and higher breakdown viscosity and lower setback viscosity than the native pea flour demonstrated that extrusion reduced the thermal stability and retrogradation tendency. Increasing extrusion temperatures greatly reduced the relative crystallinity (based on X-ray diffraction analysis) from 32.69% relative to the native pea flour to 9.76% at 90 °C. Extrusion treatment also reduced β-sheet content (based on Fourier transform infrared spectroscopy analysis) from 36.40% relative to the native pea flour to 31.79% at 90 °C. IVPD and IVSD improved, and the SDS content increased at 50 °C and 70 °C, thereby indicating that extruded pea flour can be applied to healthy food products.

Dual modification of achira (Canna indica L) starch and the effect on its physicochemical properties for possible food applications

The aim of this study was to evaluate the effect of acid hydrolysis and succination upon single and a combination of both of them as a dual modification on the morphological, structural, thermal, and pasting profile of the achira starch in order to expand its potential food applications. The surface of achira starch granules was eroded with acid hydrolysis, while the succination resulted in the formation of pores or cavities, having a slight impact on the crystallinity and the gelatinization enthalpy. Succinated starch presented the lowest transition temperatures (To = 60.29 °C, Tp = 65.03 °C and Te = 69.86 °C) compared to other starches in this study. The succination increased the final viscosity (3808 cp) when compared with the native starch (3114 cp), while acid hydrolysis resulted in a decreased value (735 cp). These are desirable properties for its possible use as an additive in bakery industry processes.

Impact of ultra-fine milling and air classification on biochemical and techno-functional characteristics of wheat and rye bran

Dry milling and air classification were applied to produce three different ingredients from wheat and rye brans. Dried and pin disc-milled brans having particle size medians of 89-131 µm were air classified to produce protein- and soluble dietary fibre-enriched hybrid ingredients (median particle size 7-9 µm) and additionally brans were ultra-finely milled (median particle size 17-19 µm). The samples were characterised in regard to their composition and techno-functional properties. In air classification, protein content increased from 16.4 and 14.7% to 30.9 and 30.7% for wheat and rye brans, which corresponded to protein separation efficiencies of 18.0 and 26.9%, respectively. Concurrently, the ratio between soluble and insoluble dietary fibre increased from 0.22 to 0.85 for wheat and from 0.56 to 1.75 for rye bran. The protein- and soluble dietary fibre-enriched wheat bran fraction showed improved protein solubility at alkaline pH when compared to pin disc- and ultra-finely-milled wheat bran, whereas less difference between the wheat ingredients was observed at native and acidic pH. The protein- and soluble dietary fibre-enriched rye bran fraction exhibited lower solubility than the pin disc- or ultra-finely-milled rye brans at all the studied pH-values. Ultra-fine milling alone decreased protein solubility and increased damaged starch content when compared to the pin disc-milled brans. Both protein enrichment and ultra-fine milling improved colloidal stability in comparison to the pin disc-milled raw materials. The lowest water and oil binding capacities were obtained for the protein-enriched fractions. Ultrasound-assisted emulsification of the protein- and soluble dietary fibre-enriched fractions and the ultra-finely-milled brans revealed no major differences in the visual quality or stability of the emulsions. The results suggest that modification of the techno-functional properties of cereal brans may be acquired via both air classification and ultra-fine milling.

Water irrigation management affects starch structure and physicochemical properties of indica rice with different grain quality

The effects of water irrigation management including conventional irrigation (CK), constant flooding irrigation (CFI) and alternate wetting and drying (AWD) on starch structure and physicochemical properties of two indica rice cultivars with good- and poor-quality were evaluated in the field condition with two years. The results showed that AWD could significantly increase peak viscosity, breakdown and gelatinization temperature, decreased setback and gelatinization enthalpy in two indica rice cultivars. However, starch granule size and amylopectin chain length distribution were differed the trends in the rice cultivars and treatments. AWD reduced starch granules size and amylopectin short chain, especially for large starch granules, but increased medium and long chain, which might contribute to better thermal stability and pasting viscosity for good-quality cultivar. Our study indicated that water irrigation management affected starch structure and physicochemical properties of indica rice starch, and would provide favorable information for improvement of rice starch in food industry.

Effects of potassium sulfate on swelling, gelatinizing and pasting properties of three rice starches from different sources

This study evaluates the effects of potassium sulfate (K₂SO₄) on the swelling, gelatinization, and pasting properties of indica rice starch (IRS), japonica rice starch (JRS), and waxy rice starch (WRS). As a result, the gelatinization temperatures (T_p), swelling capacities, and pasting viscosities of rice starches in water followed the order of WRS > JRS > IRS, showing positive correlations to amylopectin content and molecular weight. At K₂SO₄ concentration of 0.05-0.6 M, T_p increased by 10-13 ℃ due to a more compact structure of starch granules resulting from increased interactions of starch chains with K⁺. However, the swelling capacity decreased with increasing K₂SO₄ concentration and followed the order of WRS < JRS < IRS, which decreased sharply from 27.3 to 2.5 g/g for WRS. K₂SO₄ dramatically reduced the pasting viscosity of starch pastes due to the decreased swelling capacity. This study provides the scientific basis for rice starch processing with K₂SO₄.

Effect of Sprouting on Proteins and Starch in Quinoa (Chenopodium quinoa Willd.)

This study aims at understanding the relation among sprouting time (from 12 up to 72 h), changes in protein and starch components, and flour functionality in quinoa. Changes related to the activity of sprouting-related proteases were observed after 48 h of sprouting in all protein fractions. Progressive proteolysis resulted in relevant modification in the organization of quinoa storage proteins, with a concomitant increase in the availability of physiologically relevant metals such as copper and zinc. Changes in the protein profile upon sprouting resulted in improved foam stability, but in impaired foaming capacity. The increased levels of amylolytic enzymes upon sprouting also made starch less prompt to gelatinize upon heating. Consequently, starch re-association in a more ordered structure upon cooling was less effective, resulting in low setback viscosity. The nature and the intensity of these modifications suggest various possibilities as for using flour from sprouted quinoa as an ingredient in the formulation of baked products.

Evaluation of pasting and gelling properties of commercial flours under high heating temperatures using Rapid Visco Analyzer 4800

In this study, pasting and gelling behaviors of flours were investigated at heating temperatures of 95-140 °C. Overall, both peak and breakdown viscosities of the flours were positively correlated with starch contents (p < 0.01) but inversely correlated with protein (p < 0.01) and fiber contents (p < 0.05) at 95-140 °C. When the heating temperature increased, pasting temperatures and peak viscosities of most waxy and normal flours largely remained the same, but their holding strengths and final viscosities gradually decreased. However, pulse and high-amylose maize flours required a holding temperature above 95 °C to achieve the highest peak and final viscosities. Normal maize and pulse flours formed hard gels after cooking at 120 °C, and high-amylose maize flour developed the firmest gel after cooking at 140 °C. Chemical compositions, particle sizes, and thermal properties of the studied flours influenced their pasting and gelling properties to certain levels under the different heating temperatures.

Pulsed electric field assisted modification of octenyl succinylated potato starch and its influence on pasting properties

The physicochemical properties and structural changes of potato starch esterified with octenyl succinic anhydride (OSA) assisted with pulsed electric field (PEF) were investigated. Results showed that PEF treatment during esterification resulted in a significant modification of pasting properties. The pasting temperature at 2-6 kV/cm reduced by 7.6-15.1 °C for PEF-assisted OSA starches but only by 3 °C for OSA modified starch without PEF treatment as compared to that of native starch. PEF-assisted esterification could reduce the reaction time and improve the reaction efficiency over the control by 6.1-39.1 %. A novel schematic model on structure-functionality relationship for PEF-assisted OSA modified starch was proposed. Structural disorganizations of starch induced lower pasting temperature and paste viscosity. The results suggest that PEF could be a potential eco-friendly and cost-effective physical technique to prepare starch products with desired paste behaviors and to broaden its application area especially in papermaking and textile industries.

Effect of fats and oils on pasting and textural properties of wheat flour

Effects of fats and oils on pasting and textural properties of soft and hard wheat flours were investigated. Fats and oils significantly diminished peak viscosity, trough, breakdown, setback, final viscosity and escalated the pasting temperature. Effects on pasting properties were found more noticeable for soft wheat flour. Pasting properties of soft and hard wheat flour were significantly affected by coconut oil and hydrogenated fat. Texture analyser results divulged that fats and oils decreased the flour gel hardness, adhesiveness, gumminess and chewiness of flour gel of both varieties, whereas gel springiness was improved. Textural properties of wheat flour gels of both soft and hard wheat varieties were influenced most extensively by groundnut oil.

Pasting, viscoelastic and rheological characterization of gluten free (cereals, legume and underutilized) flours with reference to wheat flour

In this study, the rheological properties of dough prepared from gluten free flours (rice, sorghum, moong, water chestnut and unripe banana) and wheat dough were determined. Pasting properties and viscoelastic properties were analyzed using rheometer and dough rheology experiment was performed on texture analyzer. Water chestnut flour exhibited highest peak viscocity (22.6 Pa s), trough viscosity (12.1), breakdown viscosity (10.5 Pa s) and final viscosity (14.92 Pa s) than others while unripe banana flour showed highest setback viscosity (4.54 Pa s). Pasting temperature was found to be highest for sorghum followed by wheat and others. The highest elastic (G') and loss (G″) module were obtained for moong flour. Wheat and gluten free flours were found to exhibit thixotropic effect. Moong flour dough was found to be the stickiest (dough stickiness 57.83 g) followed by WCF, UBF, wheat, rice and sorghum. Similar trend was observed for dough strength. These flours can be proved as key materials for the gluten-free products market and can provide additional inexpensive advantage to the food processing industry.

Relationship between structure and physicochemical properties of ginkgo starches from seven cultivars

The structures and physicochemical properties of ginkgo starches from seven cultivars were investigated and their relationships analyzed. The ginkgo starches had oval or irregular shapes, size distributions with a unimodal peak, and an A-type crystal pattern. The fine structures, crystalline structures, and physicochemical properties varied significantly among these ginkgo starches. Pearson correlation analysis and a PCA loading plot indicated that amylopectin A-chains and amylose had negative effects on the IR ratio, I_max, and D, while amylopectin B-chains had a clear positive effect on the relative crystallinity. Furthermore, the amylopectin short B1-chains and long B-chains contributed amorphous and single-helix structures, respectively. The thermal properties of the ginkgo starches were mainly influenced by the amylopectin B-chains and I_max, while the pasting properties were mainly influenced by amylopectin B-chains and helical structures. These results indicated that the starch fine structures and crystalline structures had significant effects on the physicochemical properties.

Modification of the functional properties of hard-to-cook cowpea seed flours and cooked prepared pastes by γ-irradiation

Cowpeas are an inexpensive source of quality protein but their utilisation is limited by long seed cooking time. This is exacerbated by development of the hard-to-cook (HTC) defect, which also adversely affects starch and protein functionality. Gamma-irradiation can eliminate cowpea seed insect infestation and affects seed functional properties, including reducing cooking time. Hence, the potential of γ-irradiation to modify the starch- and protein-related functionalities of HTC cowpeas was investigated. Gamma-irradiation at approximately 11 kGy was applied to the seeds of two cowpea varieties, differing in HTC susceptibility, where HTC had been induced by high-temperature, high-humidity (HTHH) storage. HTHH storage increased flour pasting peak viscosity by up to 40% in the less susceptible variety and by more than 100% in the more susceptible variety. Gamma-irradiation at least completely reversed this effect, due to starch depolymerisation and debranching. Gamma-irradiation also positively impacted on some protein-related properties adversely affected by HTC; partially reversing the reduction in flour and cooked paste nitrogen solubility index of the HTC-susceptible cowpea, as a result of protein depolymerisation. The multiple benefits of γ-irradiation: disinfection, cooking time reduction and reversing some adverse effects of HTC on functional properties could make it a viable process for improving HTC cowpea quality.

Development, formulation and shelf life evaluation of baby corn soup mix from industrial by-products

The research study was conducted to utilize by-products of baby corn in the development of soup mix. Baby corn powder was obtained by drying and grinding of cut pieces of baby corn. Different formulations of soup mixes were prepared by altering the level of baby corn powder (10-40%), corn flour, salt, mango, onion, garlic, cumin, black pepper, coriander and sugar powders. Formulation 2-baby corn powder:corn flour:onion powder:garlic powder:salt:sugar:mango powder:coriander powder:cumin powder:black pepper in ratio of 20:42:2:2:10:6:15:1:1:1 was selected best on the basis of proximate, functional, pasting and sensory parameters. Soup mix was stored under ambient conditions and a declining trend was observed for antioxidant activity (67.64-48.41% DPPH inhibition), water absorption index (3.15-2.58 g/g), pH (6.81-4.15) and sensory score whereas total plate count, moisture and viscosity were found increasing after every 15 days interval. After 5 months of storage, color and sensory parameters declined. This study is valuable in promoting exploitation of by-products of baby corn by preparing soup mix that can alleviate the problem of postharvest losses and by-product utilization.

Effects of experimental warming on physicochemical properties of indica rice starch in a double rice cropping system

To evaluate the actual response of rice starch physicochemical properties to climate warming, a field warming experiment was conducted with four indica rice cultivars using free-air temperature increase (FATI) facility in a double rice cropping system. FATI facility increased rice canopy temperature by 1.4-2.1 °C during the entire growth period. The responses of starch physicochemical properties to experimental warming were basically consistent for both early and late rice. On average, experimental warming increased the starch relative crystallinity, granule average diameter, and amylopectin average chain length by 14.3%, 6.9%, and 2.4%, respectively. These resulted in starch with lower swelling power, water solubility, and pasting viscosity, but higher gelatinization temperatures and gelatinization enthalpy. Our study indicated that experimental warming affected the rice starch physicochemical properties, and would provide some useful information on how to guide the rice starch end use in food and non-food industries under climate warming.

Effects of temperature and shear on the structural, thermal and pasting properties of different potato flour

Background

The properties of potato flour will be different due to different processing parameters, which will affect their processing adaptability. In this paper, different potato flour were investigated to determine viscoelastic properties and structural transformation using thermodynamics, rheological and spectrum methods. Potato flour was prepared by drying at different temperature after soaking in citric acid, microwave and steamed respectively. The treated samples were dried by hot air and then compared with the freeze-dried potato flour. Four kinds of potato flour showed different properties after shearing at high temperature.

Results

Differential scanning calorimetry (DSC) results revealed that potato flour with low gelatinization had lower enthalpy and faster melting process than freeze-dried potato powder. RVA and texture results showed that potato flour with low gelatinization had the best retrogradation property and the stable gel. X-ray diffraction (XRD) patterns revealed that the crystalline properties of different potato flour after shearing at high temperature were the same. In addition, low gelatinization potato flour presented a crystalline structure or strong internal order. Fourier-transform infrared spectroscopy (FTIR) spectra showed that high temperature and shearing mainly caused δ-deformation of O-H in intact potato granules.

Conclusion

Freeze drying and hot air drying at low temperature made potato flour had better gel stability than microwave and steamed treatment. Hot air drying at low temperature made potato flour had good retrogradation after hot shearing, which was more conducive to the formation of hot-processed products.

Effect of low temperature on the aging characteristics of a potato starch gel

In this work, the freezing curve of a potato starch gel with different concentrations was determined. The water migration, texture, microstructure and gelatinization of a potato starch gel with 8% starch concentration were studied during aging. The results showed that the freezing characteristics of the potato starch gel with different starch concentrations were quite different. NMR results showed that the relaxation time and proportion of water with different existing states (T₂₁, T₂₂ and T₂₃) in the potato starch gel varied significantly under different aging temperatures. Under different aging temperatures, the texture characteristics and the gel strength of the starch gel were significantly different. The water retention of the gel was better under aging temperatures of 3 °C and -3 °C than for other gel samples. SEM and C-cell results showed that under aging temperatures of 3 °C and 0 °C, the formation of a gel network structure was accelerated, and the gel was relatively firm, with small and uniform pores and a larger pore area and number. The rapid viscosity analysis results showed that the peak viscosity, breakdown and setback of the vacuum freeze-dried gel powder changed differently under the aging temperatures.

Cooking, morphological, mechanical and digestion properties of cooked rice with suppression of starch branching enzymes

Kernel components and some physicochemical properties of cooked rice were investigated and compared between a popular japonica rice Wu-xiang 9915 (WX) and its transgenic line (WX-SBEI/IIb^-) with suppression of starch branching enzyme I/IIb. The starch content, especially amylopectin content, was significantly lower in WX-SBEI/IIb^- than in WX. Brown rice flour had markedly higher gelatinization temperature in WX-SBEI/IIb^- than in WX. The cooked kernels of WX-SBEI/IIb^- had significantly lower volume swelling, leached material amount and wet weight than those of WX during cooking. Starch granules in WX kernel could be gelatinized completely and gradually from the exterior to the interior of endosperm, leading to breakage of cooked kernels. However, aggregate, elongated and small starch granules in the exterior of WX-SBEI/IIb^- endosperm could not be gelatinized completely and remained their morphologies during cooking, leading to a high resistance of kernels to cooking. Brown rice flour of WX-SBEI/IIb^- had significantly lower pasting viscosities, storage modulus and loss modulus but higher loss angle tangent than that of WX. The cooked kernels of WX-SBEI/IIb^- had considerably higher hardness, springiness and cohesiveness but lower adhesiveness than those of WX. The starch in cooked kernels was more resistant to digestion in WX-SBEI/IIb^- than in WX.

Physicochemical properties of potato starches manufactured in Hokkaido factories

Potato starch is an important agricultural product in Hokkaido, the northernmost island of Japan, with output of around 0.18 million tons/year. The present investigation was conducted to evaluate the physicochemical properties of potato starch samples manufactured in 10 factories in Hokkaido. The starch samples were analyzed for pasting properties by rapid visco analyzer (RVA), gelatinization properties by differential scanning calorimetry (DSC), color components, and minerals, amylose, and resistant starch (RS) contents. The phosphorus and potassium contents of potato starches averaged 746 ppm and 681 ppm, ranging from 669 to 835 ppm and from 481 to 803 ppm, respectively. Relatively wide ranges were noted in the contents of sodium (35-134 ppm), magnesium (50-121 ppm), and calcium (34-164 ppm). RVA analysis revealed clear differences in peak viscosity (PV) and breakdown (BD) among starch samples examined. Higher contents of divalent cations, magnesium, and calcium, were associated with lower values of PV and BD, whereas the phosphorus content did not affect PV and BD. The differences in amylose content, DSC gelatinization properties and color components as well as RS content in raw starch were not large.

Impact of γ-irradiation on physicochemical characteristics, lipoxygenase activity and antioxidant properties of finger millet

In the present study, the finger millet grains were subjected to γ-irradiation at four different dosage levels: 2, 5, 10, and 15 kGy. Effect of γ-irradiation on the proximate composition, pasting properties, lipoxygenase activity, and antioxidant properties of finger millet flour was evaluated. Moisture, protein, fat, ash, and carbohydrate content of native flour was 12.96, 6.85, 2.73, 1.57, and 73.69 g/100 g, respectively. According to the results of proximate analysis, γ-irradiation significantly (p < 0.05) reduced the moisture contents and increased protein contents; however, the fat content of the irradiated flour was equal to or lower than that of the native flour. Pasting properties of the finger millet flour was reduced with the γ-irradiation. Compared with the native flour, lipoxygenase activity and malondialdehyde content decreased and radical scavenging activity, catalase, and superoxide dismutase activities increased in the irradiated flour with increasing γ-irradiation doses. Finally, the present study suggested that the γ-irradiation process improved the antioxidant enzymes and physicochemical characteristics; which could be helpful in formulating tailored made food products.

Effects of sprouting and cooking processes on physicochemical and functional properties of moth bean (Vigna aconitifolia) seed and flour

Selected moth beans (Vigna aconitifolia) were subjected to different processes such as sprouting and cooking. Their respective flours were prepared and evaluated for their physicochemical and functional characteristics. From our study, it was observed that the ash content of raw moth bean flour was considerably higher in comparison to the sprouted and cooked moth bean flour. On the other hand, the crude lipid and fiber content of sprouted moth bean flour were remarkably higher compared to raw and cooked moth bean flour, respectively. The raw moth bean flour exhibited considerably better emulsifying activity compared to the sprouted moth bean flour. Sprouted bean flour was showing higher emulsion stability than the raw bean flours and the cooked bean flour reported zero emulsion stability. The value of foaming stability was not significantly different among raw and sprouted moth bean, but it was significantly low in cooked moth bean flour. Raw moth bean flour was found to exhibit higher gelation concentration than the sprouted and cooked flours. This study highlights the variations observed in the physicochemical and pasting characteristics of moth bean seeds (raw, sprouted and cooked) and their respective flours.

Physicochemical, thermal and structural properties of heat moisture treated common buckwheat starches

Common buckwheat starch modified by heat moisture treatment at different temperatures was analysed for functional, pasting, structural, thermal, gel textural and morphological properties. Heat moisture treatment decreased swelling power, solubility and oil absorption capacity while amplified water absorption capacity of buckwheat starch. Lower whiteness index with higher a* and b* values were observed for treated starches. Modified starches showed increased paste clarity and reduced syneresis. A declining order of paste clarity and freeze-thaw stability of native and treated starches was noticed during storage period. RVA analysis showed reduced viscosities (peak, trough, breakdown, final and setback viscosity) for hydrothermally treated starches. Increased gel hardness was observed for modified starches and starch sample treated at 85 °C produced the hardest gel. FTIR spectrums of native and treated starch samples showed peaks at similar wavenumbers. Micrographs revealed the polygonal shape of native starch granules with flat areas on surface. Increased agglomeration in heat moisture treated starch samples was noticed in scanned images of starches. X-ray diffraction analysis showed 'A' type crystalline pattern in native starch of common buckwheat and no alteration in crystalline pattern due to hydrothermal treatment was observed. Relative crystallinity of native buckwheat starch decreased during heat moisture treatment and the minimum value was recorded for starches treated at 85 °C. Differential scanning calorimetry showed raised gelatinisation temperatures (T_O, T_P and T_C) and reduced ΔH values for hydrothermal treated starches.

Kithul palm (Caryota urens) as a new source of starch: Effect of single, dual chemical modifications and annealing on the physicochemical properties and in vitro digestibility

The objective of this study was to determine the effect of physical and chemical modifications on the physicochemical and in vitro digestibility of kithul starch. Starch isolated from kithul flour (Caryota urens) was subjected to physical and chemical modifications. The starch modification was verified by the presence of functional groups using Fourier transform Infrared spectral analysis (FT-IR). X-ray Diffraction (XRD) pattern revealed that the kithul starch is A- type and the modifications did not change the crystalline pattern. However, the relative crystallinity showed significant changes. Chemical modifications increased the swelling and solubility. Pasting and thermal parameters of all modified starches showed significant changes as compared to native starch (NS). Acetylated oxidised starch (AOS) showed highest paste viscosities. Higher enthalpy of gelatinization (∆H_gel) and paste viscosity attributed to perfection and ordering of amorphous regions in annealed starch (ANS). All modifications significantly increased the resistant starch (RS) content than native starch (NS), which indicates its lower digestibility. The current study showed the single, dual chemical modifications and annealing, effectively modified the physicochemical and in vitro digestibility of kithul starch.

Quality of ready-to-eat komal chawal produced by brown rice parboiling method

Komal chawal, meaning soft rice, produced by brown rice parboiling of a low amylose rice variety chokuwa, was studied for its physical, physico-chemical, morphological and structural characteristics. The product was produced by soaking the brown rice at 60 °C for 90 min, followed by steaming and air drying to 12.0% (wb). The two steaming conditions used were: (1) open-steaming at atmospheric pressure for 20 min and (2) pressure-steaming at 1 atm (gauge) for 10 min. The three different drying temperatures used were 40, 50 and 60 °C. When soaked in water at 60 °C for 20 min the product attained a hardness value of cooked rice. The extent of changes in the kernel and flour properties as compared to the raw form were affected by the severity of the steaming condition and drying air temperature. The pressure steamed samples exhibited virtually persistent growth in paste viscosity in the profiles obtained from the rapid viscosity analyzer. X-ray diffraction analysis of flours revealed a loss of A-type pattern and formation of feeble peaks of A + V-type mixed patterns in steam-treated samples. Scanning electron photomicrographs showed the loss of the polygonal shape by starch granules during processing. The values of rehydration ratio, equilibrium moisture content for rehydration, sediment volume, extent of color change as denoted by total color difference, and the percent head rice yield were higher in pressure steamed komal chawal samples.

Assessment of physicochemical characteristics and modifications of pasting properties of different varieties of maize flour using additives

Maize cereal has potential to be used for food purpose but lack of viscoelastic behaviour that limits its use for this purpose. Therefore, present study on modification of pasting properties of maize flour using different additives was carried out. Flours of three maize varieties (PMH1, JL3459 and Buland) with and without additives (guar gum, xanthan gum, whey protein concentrate and potato starch) were analysed for physico-chemical and pasting properties. Maize (PMH1) had maximum thousand kernel weight (312.47 g), bulk density (0.80 g/ml), force to rupture (68.54 kg) and contained the highest starch (67.70%) and fat (5.08%) among the three varieties. Different levels of guar gum (0-1.0%), xanthan gum (0-1.0%), whey protein concentrate (0-15.0%) and potato starch (0-10.0%) were incorporated in flours from three maize varieties. Results showed that guar gum 1.0% (w/w basis) and xanthan gum 1.0% (w/w basis) incorporation led to the highest peak and final viscosity whereas whey protein concentrate and potato starch were not selected because of negative effect on these properties. These additives can be used as binding agent in chapati and other maize products.

The effect of different thermal modifications on slowly digestible starch and physicochemical properties of green banana flour (Musa acuminata colla)

The effect of heat moisture treatment (HMT), annealing (ANN), and dual retrogradation (DR) on functional and pasting properties, digestibility of starch components of banana flour comprising rapidly digestible starch (RDS), slowly digestible starch (SDS) and resistant starch (RS) has been investigated, using native banana flour (NBF) as a control. Crystal type, relative crystallinity and morphological changes were characterised by XRD and SEM. HMT has markedly modified the pasting properties and resulted in the highest SDS content. HMT and ANN increased the relative crystallinity but DR decreased it. HMT and DR altered XRD patterns from B to A and A + B type respectively, while ANN did not change the XRD patterns. The NBF compact granule surface remained unchanged with ANN but changed to a more porous surface with HMT and DR, thereby increasing the digestibility. Crystal type and granule morphology affected the digestibility while relative crystallinity might change the pasting point.