Morphological, physico-chemical and functional properties of underutilized starches in China

Structure and properties of Quercus robur acorn starch extracted by pulsed electric field technology

Pulsed electric field (PEF) technology was used to extract starch from Q. robur flours using low-intensity electric fields (0 and 0.1 kV/cm) and study the impact of PEF on the structure and properties of acorn starch concerning commercial starch. PEF technology is an advantageous method for starch extraction than the aqueous steeping from an industrial perspective since reduces extraction time and allows for continuous processing of larger suspension volumes. PEF technology preserved the amylose and amylopectin contents, hydrogen bonds, and diffraction patterns, as well as the starch native properties. Hence, PEF could be used to obtain native starches, but future studies should verify its economic viability. Acorn starches have lower damaged starch content, gelatinization temperatures, enthalpies, improved pseudoplastic behavior, reduced in-vitro digestibility, and lower resistance to deformation compared to commercial corn starch. The higher solubility and swelling power of acorn starches up to 80 °C make them a suitable food additive in fermented yogurt and milk products and thus help to value acorn and acorn starches. Hence, acorns can be used to obtain native starches, a food ingredient with a wide range of food and non-food usage, using PEF.

Physicochemical, thermal, pasting, morphological, functional and bioactive binding characteristics of starches of different oat varieties of North-Western Himalayas

Starches were isolated from five oat varieties (SFO-1, SFO-3, Sabzar, SKO-20 and SKO-96) grown in North-Western Himalayas of India. Moisture content of the varieties ranged from 9.25 ± 0.09 to 13.21 ± 0.11 %, indicating their shelf-stability. Results suggested >90 % purity of starches as was evident from values of ash, proteins, and lipids. Amylose content results showed that all starches fall within category of intermediate-amylose starches. Lambdamax, blue value and OD620/550 were found significantly (p ≤ 0.05) higher in SKO-20. Sabzar exhibited higher starch hydrolysis percentage of 85.16 % whereas, lowest was observed in SKO-20 (78.12 %). Degree of syneresis was higher in SKO-20 however, its freeze-thaw stability was lesser. Wide peak in FTIR spectra at 3320 cm-1 confirms nature of starches. SKO-20 exhibited significantly higher onset gelatinization temperature (65.19 ± 1.06 °C) and enthalpy (15.78 ± 0.15 J/g) whereas, Sabzar exhibited lowest enthalpy. Pasting characteristics indicated lowest and highest final viscosity in SKO-20 (341.30 ± 2.11 mPas) and SKO-96 (1470 ± 4.56 mPas), respectively. SEM results indicated irregular and polygonal shape of starches with size <10 μm. SKO-20 exhibited lowest disintegration time of 2.08 ± 0.01 min and Sabzar showed highest (3.31 ± 0.07 min). SKO-20 released more curcumin (71.28 %) whereas, Sabzar released less. This suggests that SKO-20 could be used as better excipient for delivery of curcumin at target site.

Modification of Acorn Starch Structure and Properties by High Hydrostatic Pressure

Despite being rich in starch, over half of acorn production is undervalued. High hydrostatic pressure was used to modify the properties of Q. pyrenaica (0.1 and 460 MPa for 20 min) and Q. robur (0.1 and 333 MPa for 17.4 min) acorn starches to obtain high-valued ingredients. Pressure significantly altered the span distribution and heterogeneity of the acorn starch granules depending on the species, but their morphology was unaffected. Pressurization increased the amylose/amylopectin ratio and damaged starch contents, but the effect was more prominent in Q. pyrenaica than in Q. robur. However, the polymorphism, relative crystallinity, gelatinization temperatures, and enthalpies were preserved. The pressure effect on the starch properties depended on the property and species. The solubility, swelling power, and acorn gels' resistance towards deformation for both species decreased after pressurization. For Q. pyrenaica starch, the in vitro digestibility increased, but the pseudoplastic behavior decreased after pressurization. No differences were seen for Q. robur. Regarding the commercial starch, acorn starches had lower gelatinization temperatures and enthalpies, lower in vitro digestibility, lower resistance towards deformation, superior pseudoplastic behavior, and overall higher solubility and swelling power until 80 °C. This encourages the usage of acorn starches as a new food ingredient.

Insight into the Effects of Drying Methods on Lanzhou Lily Rehydration

This study investigated the effects of drying methods (hot air drying (HAD), microwave vacuum drying (MVD), and vacuum freeze drying (VFD)) on the rehydration performance (RP) of dried Lanzhou lily scales (LLS). Rehydration rate and water migration showed that MVD had the best RP, followed by VFD, while HAD had the worst. The results of additional morphology observation using scanning electron microscopy (SEM) and micro X-ray computed tomography (CT) imaging showed that both MVD and VFD created more channels in more porous structures, which facilitated their better RP than that by HAD. The results also revealed the spatial structure diversity (including pores, channels size, and internal network) of each dried Lanzhou lily scale group. In addition, studies analyzed how drying techniques affected the physiochemical properties of lily starch, including its water solubility, pasting profiles, and starch particle morphology. The findings indicated that when MVD was in operation, partial gelatinization in lily starch was brought about by thermal effects, allowing MVDS crystals to change from B-type to V-type and causing MVDS to have better water absorption ability. Consequently, despite the fact that MVD's desiccated lilies have a lower porous structure and thinner channels than VFD's, MVD has a higher RP than VFD.

Optimization of starch extraction from Amorphophallus paeoniifolius corms using response surface methodology (RSM) and artificial neural network (ANN) for improving yield with tenable chemical attributes

The development of the extraction process for improving the starch yield from unconventional plants is emerging as a topic of interest. In this respect, the present work aimed to optimize the starch extraction from the corms of elephant foot yam (Amorphophallus paeoniifolius) with the help of response surface methodology (RSM) and artificial neural network (ANN). The RSM model performed better than the ANN in predicting the starch yield with higher precision. In this connection, this study for the first time reports the significant improvement of starch yield from A. paeoniifolius (51.76 g/100 g of the corm dry weight). The extracted starch samples based on yield - high (APHS), medium (APMS), and low (APLS) exhibited a variable granule size (7.17-14.14 μm) along with low ash content, moisture content, protein, and free amino acid indicating purity and desirability. The FTIR analysis also confirmed the chemical composition and purity of the starch samples. Moreover, the XRD analysis showed the prevalence of C-type starch (2θ = 14.303°). Based on other physicochemical, biochemical, functional, and pasting properties, the three starch samples showed more or less similar characteristics thereby indicating the sustentation of beneficial attributes of starch molecules irrespective of the variation in extraction parameters.

Heat-moisture modified blue wheat starch: Physicochemical properties modulated by its multi-scale structure

Blue wheat starch was modified by heat-moisture treatment (HMT) with varying moisture contents (MCs). Changes in physicochemical properties were evaluated on the basis of its multi-scale structure. Following HMTs with MC below 30 %, the starch remained brighter and presented total phenolics content up to 0.20 mg/g. As treating MC increased, structural disruptions became more pronounced, which were characterized by crystallinity loss, lamellae's loosening, hydrogen bonding breakage, and debranching. Furthermore, HMTs decreased the proportion of external A chains of amylopectin. Concomitantly, modified starches showed progressively increased transition temperatures but decreased enthalpy values. Despite the swelling power decrease, HMTs with MC of 15 % showed markedly higher peak viscosity than control, as a result of the more compact semi-crystalline lamellae and homogenous electron distribution. Besides, all HMT-starches showed lowered breakdown and setback. This novel modified starch would be promising ingredients for modulating the viscoelasticity of healthy anti-staling staple foods.

Current trends in the preparation, characterization and applications of oat starch - A review

Worldwide consumption of oats is gaining popularity due to its composition and multifunctional benefits of individual components. Oat starch being the major component accounts up to 60% of the dry weight of kernel, possess small granule size and high lipid content. Properties of starch substantially affect the quality of the product. Modification and characterization of starch is important for their specific applications that increase the utilization of oat starch. Different modification techniques greatly affect the functional, pasting, gelatinisation, textural, rheological, retrogradation properties and enzymatic digestibility of oat starches in comparison to native starch. Modified oat starch competes against other abundant and inexpensive cereal starches (rice and corn) that are available in modified forms in the market. This review summarises the current knowledge of physicochemical, morphological, pasting, functional, rheological and gelatinization properties, developments in the extraction and modification (physical, chemical and enzymatic) and applications of oat starch. Thus, this review will upgrade the scientific basis on oat starch being a unique source of starch for variety of applications.

Crosslinked starch-coated cellulosic papers as alternative food-packaging materials

In general, during the production of cellulosic materials for food-packaging applications, lignin and other amorphous components are usually removed via the pulping and multilevel bleaching process to entirely separate them from the fiber.

Insights into the correlations between the size of starch at nano- to microscale and its functional properties based on asymmetrical flow field-flow fractionation

In this study, the starches were isolated from three botanical sources (i.e., rice, sweet potato, and lotus seed). The size distributions of starch granules and molecules were determined by asymmetrical flow field-flow fractionation (AF4), and compared with those measured from optical microscopy (OM) and dynamic light scattering (DLS). Furthermore, the starches were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). AF4 coupled online with UV-visible, multiangle light scattering (MALS), and differential refractive index (dRI) detectors (AF4-UV-MALS-dRI) was employed for the investigation of the digestion and retrogradation properties of starches. Meanwhile, the relationships between the size of starch at nano- to microscale and its functional properties (i.e., digestibility, retrogradation, and thermal properties) were studied by Pearson correlation analysis. AF4-UV-MALS-dRI was proved to be a rapid and gentle method for the separation and size characterization of starches at both micro- and nano-molecule levels. Moreover, it was demonstrated that AF4-UV-MALS-dRI is a useful tool for the monitoring of the digestion and retrogradation properties of starches. The results suggested that the sizes of starch granules and molecules were to some extent correlated with their thermal properties and digestibility, but not with retrogradation property.

Composition, Physicochemical Properties, and Uses of Acorn Starch

The major component of acorn is starch, which may amount up to 55% of the dry weight. Lack of systematic knowledge on acorn starch greatly hinders the further development of acorns as sustainable crops. This review aims to summarize the current knowledge of the isolation, chemical composition, physicochemical properties, and uses of acorn starches and to provide future research directions. The amylose content of the acorn starches is reported to vary in the range of 20–39%. Moisture content, lipid, ash, and protein contents of the acorn starches have been reported varying from 2.20 to 15.50%, 0.23 to 2.64%, 0.01 to 1.41%, and 0.01 to 6.7%, respectively. Thermal and pasting properties that have usually been determined using differential scanning calorimeter (DSC) and rapid viscoanalyzer (RVA) are also discussed in this article. Acorn starch has great potential for various food and nonfood applications due to the unique structural and functional features.

Physical, Chemical and Rheological Characterization of Tuber and Starch from Ceiba aesculifolia subsp. parvifolia

This work aimed to evaluate the physical, chemical and antioxidant properties of Ceiba aesculifolia subsp. parvifolia (CAP) tuber and determinate rheological, thermal, physicochemical and morphological properties of the starch extracted. The CAP tuber weight was 3.66 kg; the edible yield was 82.20%. The tuber presented a high hardness value (249 N). The content of carbohydrates (68.27%), crude fiber (15.61%) and ash (9.27%) from the isolated starch, reported in dry weight, were high. Phenolic compounds and flavonoid content of CAP tuber peel were almost 3-fold higher concerning the pulp. CAP tuber starch exhibited a pseudoplastic behavior and low viscosity at concentrations of 5-15%. Purity percentage and color parameters describe the isolated starch as high purity. Thermal characteristics indicated a higher degree of intermolecular association within the granule. Pasting properties describes starch with greater resistance to heat and shear. CAP tuber starch has X-ray diffraction patterns type A. The starch granules were observed as oval and diameters ranging from 5 to 30 µm. CAP tuber could be a good source of fiber and minerals, while its peel could be used for extracting bioactive compounds. Additionally, the starch separated from this tuber could be employed as a thickening agent in food systems requiring a low viscosity and subjected to high temperatures.

Acorn flour properties depending on the production method and laboratory baking test results: A review

Acorns, the fruit of the oak, have long been an important source of food in different cultures around the world. Despite their long culinary tradition, they have become under-appreciated. Due to their high starch content, acorns are mainly used for flour production, and acorn flour is considered as a replacement for cereal flour in a wide range of applications in food production. This study reviewed the published literature concerning acorn flour production and composition as well as the possibility of using acorn flour in the most popular flour-based products such as bread, cake, and cookies. The study also presents the advantages resulting from acorn flour incorporation to the human diet and acorn flour influence on the quality of bread and pastry products. This review found that acorn flour is characterized by a lack of gluten proteins and a high content of fiber and minerals as well as the presence of polyphenols with antioxidant properties. However, negative impact of its larger amount on the dough rheological features and product physical properties has been emphasized in many studies. The researchers recommend the incorporation of acorn flour up to a level of 15% in formulating composite flour for bread production. However, the literature data indicates that acorn flour substitution for pastry production depends on the product type and ranges from 10 to even 60%. It is also highlighted that the application of acorn flour into gluten-free products is particularly favorable from a nutritional point of view.

Morphological and physicochemical characterization of starches from underground stems of Trimezia juncifolia collected in different phenological stages

In this study, starches from underground stems of Trimezia juncifolia were evaluated during dry season (DSS), wet season (WSS) and sprouting (SS). Results evidenced that drought stress did not interfere with the yield, amylose content and degree of polymerization (DP) of amylopectin. However, the extraction yield in SS was 58% lower, being observed and increase of 7.5% in the content of amylose, and 13.5% in DP values for SS amylopectin, with a predominance of A-chains. The amount of total sugar, the starch granules size as well as solubility and swelling properties varied as function of the phenological status. Also, starch granules changed from A-type polymorph in DSS and SS to a C_A-type in WSS. Nevertheless, it was observed a crystallinity reduction from 56% in DSS to 37.1% in SS. In addition, thermograms evidenced the presence of amylose-lipid complexes, with endothermic transition temperatures being affected by drought stress and sprouting. Finally, results demonstrate that underground stems from T. juncifolia have adaptative strategies involving changes in the morphological and physicochemical properties of the starch granules.