Comparison of structural and functional properties of starches from five fruit kernels

An antioxidant composite film based on loquat seed starch incorporating resveratrol-loaded core-shell nanoparticles

A Novel bioactive food packaging film was prepared from non-grain sourced loquat seed starch (LSS) incorporated with resveratrol-loaded nanoparticles (NRs) based on a zein/pectin core-shell system, where the NRs were prepared using the anti-solvent method. The chemical constitution of the LSS was analyzed. The film was characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The physical, optical, and antioxidant properties of the films were also identified. The results showed that incorporating NRs into the films significantly increased antioxidation activity, although simultaneously decreasing light transmission, water content, and elongation at break properties. Furthermore, NRs (15 %) facilitated strong hydrogen bonding interactions with the LSS matrix, improving the barrier properties and tensile strength. The resveratrol release behavior of the composite films in ethanol solutions (10 % and 95 % in water, v/v) as a food simulant was also investigated. The LSS/NRs composite film is effective in delaying unwanted oxidation during the storage of soybean oil. In conclusion, LSS could be applied as a good film-forming matrix, and LSS films containing NRs exhibit excellent physical properties and antioxidant activity, making them ideal for convenience foods containing a grease mixture of spices and grease-class packaging.

A study focusing on the distinct fine structure of starch in mealy and waxy potatoes

In this research, we examined the fine structure of starch in three mealy and three waxy potato varieties to understand their impact on potato texture. This research revealed significant variations in starch granule morphology, particle size, crystalline structure, molecular structure, and pasting properties between the different textures. Mealy potato starch granules appeared as rounded ovoid with inconsistent particle sizes (ranging from 35.9 to 41.8 μm), whereas waxy potato starch granules exhibited sharp polygonal shapes with consistent larger sizes (42.1-49.7 μm). While both types displayed a B-type crystalline morphology, the relative crystallinity of mealy potato starch (31.28%, 38.00% and 29.07%) is higher than that of waxy potato starch (27.38% 26.68% and 26.12%) as determined by X-ray diffraction. Additionally, the mealy potato starches had lower amylopectin content, degree of branching, short-chain amylopectin content, and molecular weight, but higher trough viscosity, final viscosity, and setback value than waxy potato starches. These differences in fine structure contributed significantly to the variations in texture between mealy and waxy potato starches, highlighting potential implications for breeding programs aimed at improving specific textural attributes for targeted application in the food industry.

Longan seeds used as novel resources to prepare resistant starch: structure, properties and digestion

In the present study, the preparation of resistant starch from longan seeds was investigated, and the properties and in-vitro digestibility of this resistant starch were further determined. Longan seed resistant starch (LRSI, LRS-II, and LRS-III) was successfully prepared, by once retrogradation, twice retrogradation and combining retrogradation and debranching, respectively. All LRS groups had higher amylose content (from 422.1 to 462.4 g/kg) and increased particle size than those of longan seed starch (LSS). Meanwhile, the resistant starch exhibited a B-type crystalline structure, and showed a block, uneven and irregular microstructure. Compared with LSS group, LRS groups exhibited higher crystallinity (from 49.03 to 56.14 %), more of short-range ordered structure (DO: from 0.771 to 0.775, DD: 0.808 to 0.942), and lower molecular weight (Mw: from 2.43 to 2.81 × 105 Da). Moreover, LRS groups showed lower viscosity during gelatinization and weaker binding capability to iodine than those of LSS group. Furthermore, all LRS groups exhibited strong resistance to enzymatic hydrolysis with high content of resistant starch (from 360 to 398 g/kg) and low rate of in-vitro digestion (k: from 23.87 to 33.74, C∞: from 63.5 to 65.5). All present results suggest that longan seeds show the potential to prepare resistant starch applied in food industry.

Starch Hydrogels for Slow and Controlled-Release Fertilizers: A Review

Fertilizers are widely used to increase agricultural productivity and ensure food security. However, their excessive use negatively impacts the environment, as a large portion is lost through leaching, degradation, and evaporation. Starch-based hydrogels (SHs) offer a promising alternative to mitigate these environmental effects by enabling the controlled release of nutrients. SHs are biodegradable, non-toxic, and biocompatible, making them attractive for agricultural applications such as soil remediation and fertilizer delivery. These materials consist of crosslinked, three-dimensional networks with high water absorption capacity. Their effectiveness in nutrient delivery depends on the synthesis method, nutrient source, and environmental conditions. While the literature on SHs is growing, most studies focus on laboratory-scale production, which limits their broader application in agriculture. This review aims to consolidate current knowledge on SHs and identify research gaps to guide the development of more efficient and environmentally friendly SH-based fertilizers. It provides an overview of SH formation methods, including graft copolymerization, chemical crosslinking, and physical interactions. Additionally, the review highlights SH applications in controlled fertilizer release, discussing encapsulation capacity, large-scale production techniques, and nutrient delivery in aqueous media, soils, seeds, and plants.

Characterization and Comparison of Structure and Physicochemical Properties of Highland Barley Starch of Different Colors

Domesticated highland barley is an important starch reserve and has differently colored grains, owing to different genotype backgrounds and cultivation environments. In this study, black, purple, blue, and yellow highland barley varieties were planted under the same cultivation conditions, and their starch distribution, structural characteristics, and physicochemical properties were analyzed. The apparent amylose content was highest in the purple variety (20.26%) and lowest in the yellow variety (18.58%). The different varieties had three subgroups and A-type crystalline structures, but the particle size and relative crystallinity (25.67-27.59%) were significantly different. In addition, the weight average molecular weight (6.72 × 107 g/mol), area ratio of APs to APL (2.88), relative crystallinity (27.59%), and 1045/1022 (0.730 cm-1) of starch were higher in yellow highland barley (YHB), forming a stable particle structure and increasing the Tp and PV of its starch. A cluster heat map showed that starches from differently colored highland barley vary in fine structure, water solubility, swelling power, and thermal and pasting properties. This study provides a reference for the high-quality breeding of colored highland barley and its utilization in food and non-food industries.

Optimization of ultrasound-assisted extraction of mango cotyledon starch: Physicochemical, structural, thermal and functional properties

Mango (Mangifera indica L.) seed, a byproduct of mango pulp and juice processing, is recognized for its abundant starch content. The advancement of the modern food industry has prompted a shift away from traditional starch extraction methods due to their environmental impact and low efficiency. The study aimed to optimize the ultrasound-assisted extraction process of starch from the cotyledons of mango seeds, employing response surface methodology with a customized optimal design and an optimal-I optimality criterion. We investigated the effects of cotyledon/water ratio, time, power, and sonication frequency on maximizing starch extraction yield. We explored the impact of ultrasound on structural, morphological, functional, and pasting properties. The maximum starch extraction yield was 50.74%. This yield was about 82.4% higher than that of conventional wet extraction. Ultrasound-assisted extraction increased starch purity and amylose content; it reduced granule size while enhancing all starch pasting properties without affecting starch's chemical structure and morphological, thermal, and functional properties. The mango cotyledon starch can be classified as medium to normal amylose content starches, exhibiting A-type polymorphs, fast-swelling, and capable of forming strong, firm, low-sticky gels. These results demonstrate the potential applications of mango residue and ultrasound technology in the food and pharmaceutical industry.

Three nonconventional starch: Comparison of physicochemical properties and in vitro digestibility

Extraction of starch from waste is also an effective way to recover resources and provide new sources of starch. In this study, starch was isolated from white kidney bean residue, chickpea residue, and tiger nut meal after protein or oil extraction, and the morphology of starch particles was observed to determine their physicochemical properties and in vitro digestibility. All these isolated starches had unique properties, among which white kidney bean starch (KBS) had a high amylose content (43.48%), and its structure was better ordered. Scanning electron microscopy revealed distinct granular morphologies for the three starches. KBS and chickpea starch (CHS) were medium-granular starches, whereas tiger nut starch was a small granular starch. Fourier transform infrared spectroscopy analysis confirmed the absence of significant differences in functional groups and chemical bonds among the three starch molecules. In vitro digestibility studies showed that CHS is more resistant to enzymatic degradation. Overall, these results will facilitate the development of products based on the separation of nonconventional starches from waste.

Effect of sulfuric acid hydrolysis on the structure and Pickering emulsifying capacity of acorn starch

The acid-hydrolyzed acorn starch samples (HAS-1, HAS-2, HAS-3, and HAS-4) were prepared from natural acorn starch (NAS) at sulfuric acid concentrations of 1, 2, 3, and 4 mol/L for 2 d. The particle characteristics and structures of HAS were investigated, and Pickering high internal phase emulsions (HIPEs) based on HAS were constructed and characterized. The results showed that with an increase in sulfuric acid concentration, the size, yield, amylose content, molecular weight, and amylopectin chain length of HAS gradually decreased. HAS retained an A-type crystal structure, and its relative crystallinity and short-range order degree gradually increased with increasing sulfuric acid concentration. Acid hydrolysis treatment improved the wettability of NAS, and its effect was positively correlated with the sulfuric acid concentration. HAS-3 and HAS-4 could stabilize the Pickering HIPEs with an oil phase volume fraction of 80% at c ≥ 1.5%. The mechanical properties of the HIPEs were positively correlated with c.

Exploring differences in the physicochemical and nutritional properties of mango flours and starches

Mangoes contain several components that are beneficial for health, in addition to being potential sources of starch for the food industry. However, a substantial amount of fruit is lost in the field because it does not meet commercial standards, resulting in food losses and environmental damage. Herein, the physicochemical properties of mango flours and starches obtained from different parts of the fruit of two cultivars were evaluated. Mango peel flours have higher levels of proteins, fibers, minerals, carotenoids, ascorbic acid, and antioxidant activity than pulp flours, in addition to a higher yellowing index and water and oil-holding capacity, and can be used as a functional flour. The pulp flours, with the higher starch content, showed characteristics that make them valuable as a potential ingredient in soft baking and gluten-free products. Mango starches have circular and oval shapes, with a bimodal distribution. All starches showed an A-type crystallinity pattern. Pulp starches showed a higher peak viscosity and breakdown, with a lower setback, and can be used as a thickening or gelling agent. The higher thermal stability of kernel starch suggests its application in sauces, baking, dairy products, and canned foods.

Using waste biomass to produce 3D-printed artificial biodegradable structures for coastal ecosystem restoration

The loss of ecosystem functions and services caused by rapidly declining coastal marine ecosystems, including corals and bivalve reefs and wetlands, around the world has sparked significant interest in interdisciplinary methods to restore these ecologically and socially important ecosystems. In recent years, 3D-printed artificial biodegradable structures that mimic natural life stages or habitat have emerged as a promising method for coastal marine restoration. The effectiveness of this method relies on the availability of low-cost biodegradable printing polymers and the development of 3D-printed biomimetic structures that efficiently support the growth of plant and sessile animal species without harming the surrounding ecosystem. In this context, we present the potential and pathway for utilizing low-cost biodegradable biopolymers from waste biomass as printing materials to fabricate 3D-printed biodegradable artificial structures for restoring coastal marine ecosystems. Various waste biomass sources can be used to produce inexpensive biopolymers, particularly those with the higher mechanical rigidity required for 3D-printed artificial structures intended to restore marine ecosystems. Advancements in 3D printing methods, as well as biopolymer modifications and blending to address challenges like biopolymer solubility, rheology, chemical composition, crystallinity, plasticity, and heat stability, have enabled the fabrication of robust structures. The ability of 3D-printed structures to support species colonization and protection was found to be greatly influenced by their biopolymer type, surface topography, structure design, and complexity. Considering limited studies on biodegradability and the effect of biodegradation products on marine ecosystems, we highlight the need for investigating the biodegradability of biopolymers in marine conditions as well as the ecotoxicity of the degraded products. Finally, we present the challenges, considerations, and future perspectives for designing tunable biomimetic 3D-printed artificial biodegradable structures from waste biomass biopolymers for large-scale coastal marine restoration.

A new source of starchy flour: Physicochemical and nutritional properties of starchy kiwifruit flour

The physicochemical and nutritional properties of three starchy kiwifruit flour (SKF) were systematically studied. The results revealed that the total starch content of SKF was 66.63-80.42%. SKF showed a B-type crystal structure with a grain size between 7.08 and 9.02 μm. In comparison to corn starch and potato starch, SKF possessed a lower pH (3.43-4.28), transparency (0.68-1.11%) and setback value (0.20-1.73 Pa·s) and a higher swelling power (9.42-15.02 g/g) and hot paste viscosity (1.73-2.10 Pa·s). Moreover, SFK was rich in protein and various mineral elements. It also contained high levels of total phenolics and exhibited a strong antioxidant capacity. The resistant starch content in SKF was as high as 67.19-73.22%, and the rapidly digestible starch content was remarkably lower than that of corn and potato starch. Overall, these unique physicochemical properties of SKF, coupled with its nutritional benefits, give it a good development potential in the food industry.

Effect of partial substitution of wheat flour with kiwi starch on dough rheology, microstructure, the quality attributes and shelf life of Chinese steamed bread

Chinese steamed bread (CSB), a conventional high-GI staple food, with a short shelf life and a single flavor. In this work, 10-20 % kiwi starch (KS) was used to substitute wheat flour for the production of CSB and the effects of different substitution ratios on the quality and shelf life of mixed flour, dough, and CSB were explored. The results showed that the substitution of KS could improve the water binding capacity of mixed flour and lead to easier pasting in the system, lower the cooking power consumption, increase and improve the viscoelasticity and gas holding capacity of the dough, and make the microstructure more compact and uniform. As the substitution ratio increased, the reduction in protein content within the system further affected the formation of the gluten network, leading to a significant decrease in the CSB's specific volume and cohesiveness, whereas the chewiness and hardness were significantly improved. Meanwhile, KS substitution significantly reduced the starch hydrolysis rate and estimated glycemic index of CSB. 10 % KS substitution enriched the aroma and color of CSB, improved its internal organizational structure, and became more popular among consumers. A substitution ratio of 15-20 % was beneficial for extending the shelf life of CSB.

Characteristics of physicochemical properties, structure and in vitro digestibility of seed starches from five loquat cultivars

Starch plays a pivotal role in food and other industries, necessitating the exploration of new starch sources to cater the substantial requirement. This study delved into the variations in the physicochemical properties, structure attributes and in vitro digestibility of seed starches extracted from five distinct loquat cultivars (Eriobotrya japonica L.). The starch extraction yield of loquat seeds was found to be 45.2 % as an average. Loquat seed starches were designated as having high-amylose starch (>50 %). The starch granules exhibited similar shapes, but granular size significantly varied across the cultivars. Loquat starches presented a C-type crystalline pattern with relative crystallinity from 17.14 % to 21.06 %. The short-range ordered structure of the starches differed with loquat cultivars. The swelling power, solubility and amylose leaching of loquat starches increased with increasing temperature, significantly varying among different cultivars. Gelatinization parameters exhibited significant variations among the loquat starches. Different loquat starches exhibited pronounced variations in paste clarity, water and oil absorption capacity. Marked differences were detected in proportions of rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS) across the five cultivars, with RS being particularly prominent fraction with an average of 84.30 %. These compressive findings offer valuable insights into the potential application of loquat seed starches in the formulation of foods and various industrial products.

Ultrasound-assisted acid/enzymatic hydrolysis preparation of loquat kernel porous starch: A carrier with efficient palladium loading capacity

Porous starch, with excellent renewal and thermodynamic stability characteristics, could be utilized as a novel carrier for metals. In this research, starch was obtained from wasted loquat kernel (LKS) and converted into loquat kernel porous starch (LKPS) through ultrasound-assisted acid/enzymatic hydrolysis. Then, LKS and LKPS were utilized for loading with palladium. The porous structures of LKPS were evaluated by the results of water/oil absorption rate and N2 adsorption analysis, and the physicochemical properties of LKPS and starch@Pd were analyzed by FT-IR, XRD, SEM-EDS, ICP-OES, and DSC-TAG. LKPS prepared by the synergistic method formed a better porous structure. Its specific surface area was 2.65 times that of LKS, and the water/oil absorption capabilities were considerably improved to 152.28 % and 129.59 %, respectively. XRD patterns showed that the presence of diffraction peaks at 39.7° and 47.1°, indicating successful palladium loading onto LKPS. The EDS and ICP-OES results revealed that the palladium loading capacity of LKPS was superior to that of LKS, with a significantly increased loading ratio of 2.08 %. In addition, LKPS@Pd exhibited excellent thermal stability, with a temperature range of 310-320 °C. Therefore, LKPS was a palladium carrier with highly efficient loading ratio, and LKPS@Pd had promising properties as a competent catalyst.

A Comprehensive Review of Pea (Pisum sativum L.): Chemical Composition, Processing, Health Benefits, and Food Applications

Pisum sativum L., commonly referred to as dry, green, or field pea, is one of the most common legumes that is popular and economically important. Due to its richness in a variety of nutritional and bioactive ingredients, the consumption of pea has been suggested to be associated with a wide range of health benefits, and there has been increasing focus on its potential as a functional food. However, there have been limited literature reviews concerning the bioactive compounds, health-promoting effects, and potential applications of pea up to now. This review, therefore, summarizes the literature from the last ten years regarding the chemical composition, physicochemical properties, processing, health benefits, and potential applications of pea. Whole peas are rich in macronutrients, including proteins, starches, dietary fiber, and non-starch polysaccharides. In addition, polyphenols, especially flavonoids and phenolic acids, are important bioactive ingredients that are mainly distributed in the pea coats. Anti-nutritional factors, such as phytic acid, lectin, and trypsin inhibitors, may hinder nutrient absorption. Whole pea seeds can be processed by different techniques such as drying, milling, soaking, and cooking to improve their functional properties. In addition, physicochemical and functional properties of pea starches and pea proteins can be improved by chemical, physical, enzymatic, and combined modification methods. Owing to the multiple bioactive ingredients in peas, the pea and its products exhibit various health benefits, such as antioxidant, anti-inflammatory, antimicrobial, anti-renal fibrosis, and regulation of metabolic syndrome effects. Peas have been processed into various products such as pea beverages, germinated pea products, pea flour-incorporated products, pea-based meat alternatives, and encapsulation and packing materials. Furthermore, recommendations are also provided on how to better utilize peas to promote their development as a sustainable and functional grain. Pea and its components can be further developed into more valuable and nutritious products.

Loquat seed starch - Emerging source of non-conventional starch: Structure, properties, and novel applications

Recently, non-conventional sources of starch have attracted attention due to their potential to provide cost-effective alternatives to traditional starch. Among non-conventional starches, loquat (Eriobotrya japonica) seed starch is an emerging source of starch consisting of the amount of starch (nearly 20 %). Due to its unique structure, functional properties, and novel applications, it could be utilized as a potential ingredient. Interestingly, this starch has similar properties as commercial starches including high amylose content, small granule size, and high viscosity and heat stability, making it an attractive option for various food applications. Therefore, this review mainly covers the fundamental understanding of the valorization of loquat seeds by extracting the starch using different isolation methods, with preferable structural, morphological, and functional properties. Different isolation and modification methods (wet milling, acid, neutral and alkaline) are effectively used to obtain higher amounts of starch are revealed. Moreover, insight into various analytical techniques including scanning electron microscopy, differential scanning calorimetry, and X-ray diffraction used to characterize the molecular structure of the starch are discussed. In addition, the effect of shear rate and temperature on rheological attributes with solubility index, swelling power, and color is revealed. Besides, this starch contains bioactive compounds that have shown a positive impact on the enhancement of the shelf-life of the fruits. Overall, loquat seed starches have the potential to provide sustainable and cost-effective alternatives to traditional starch sources and can lead to novel applications in the food industry. Further research is needed to optimize processing techniques and develop value-added products that can be produced at a large scale. However, there is relatively limited published scientific evidence on the structural and morphological characteristics of loquat seed starch. Thus, in this review, we focused on different isolation techniques of loquat seed starch, its structural and functional characteristics, along with potential applications.

Effect of environment and variety on the physicochemical properties of Tartary buckwheat starch

BACKGROUND

Starch is a major nutrient in the human diet and has been widely used as an ingredient in many food and non-food applications. However, the research on the quality characteristics of Tartary buckwheat is lagging behind, and there is a lack of high-quality special varieties, which makes it difficult to become a popular food. The physicochemical properties of Tartary buckwheat starch may be affected by different environments and varieties, and the stability of planted varieties in different regions is also an important issue in current research.

RESULTS

The average amylose content and pasting properties of Dingxi Tartary buckwheat were lower, while the solubility, transparency, relative crystallinity and gelatinization enthalpy were higher compared with the other two regions, and there were significant differences between different varieties. All samples showed typical A-type structure, and the starch short-range order structure changed slightly. Amylose content, solubility, transparency, granule size distribution, pasting properties and thermal properties were significantly affected by environment and variety.

CONCLUSION

When choosing high-quality special varieties and products for processing, it contributes to select different buckwheat varieties and planting areas based on various objectives by understanding the effects of environment and varieties on the physicochemical properties of Tartary buckwheat starch. In this study, the four varieties planted in Dingxi and the two varieties in Zhaojue were easy to digest, and the differences of pasting properties and thermal properties are helpful to improve the application of Tartary buckwheat starch in the food industry. © 2023 Society of Chemical Industry.

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.

Physicochemical, Morphological, and Cytotoxic Properties of Brazilian Jackfruit (Artocarpus heterophyllus) Starch Scaffold Loaded with Silver Nanoparticles

Due to the physical, thermal, and biological properties of silver nanoparticles (AgNPs), as well as the biocompatibility and environmental safety of the naturally occurring polymeric component, polysaccharide-based composites containing AgNPs are a promising choice for the development of biomaterials. Starch is a low-cost, non-toxic, biocompatible, and tissue-healing natural polymer. The application of starch in various forms and its combination with metallic nanoparticles have contributed to the advancement of biomaterials. Few investigations into jackfruit starch with silver nanoparticle biocomposites exist. This research intends to explore the physicochemical, morphological, and cytotoxic properties of a Brazilian jackfruit starch-based scaffold loaded with AgNPs. The AgNPs were synthesized by chemical reduction and the scaffold was produced by gelatinization. X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM-EDS), and Fourier-transform infrared spectroscopy (FTIR) were used to study the scaffold. The findings supported the development of stable, monodispersed, and triangular AgNPs. XRD and EDS analyses demonstrated the incorporation of silver nanoparticles. AgNPs could alter the scaffold’s crystallinity, roughness, and thermal stability without affecting its chemistry or physics. Triangular anisotropic AgNPs exhibited no toxicity against L929 cells at concentrations ranging from 6.25 × 10−5 to 1 × 10−3 mol·L−1, implying that the scaffolds might have had no adverse effects on the cells. The scaffolds prepared with jackfruit starch showed greater crystallinity and thermal stability, and absence of toxicity after the incorporation of triangular AgNPs. These findings indicate that jackfruit is a promising starch source for developing biomaterials.

Ultrasound-Assisted Extraction of Mango (Mangifera indica) Kernel Starch: Chemical, Techno-Functional, and Pasting Properties

(1) Background: Starch is the main component of mango (Mangifera indica) kernel, making it an alternative to obtain an ingredient from a non-conventional source with potential application in food and other industrial applications; however, reports on the use of new extraction techniques for this material are scarce. The main objective of this research was to evaluate the effect of ultrasound-assisted extraction (UAE) on the yield, chemical, techno-functional, rheological, and pasting properties of starch isolated from a non-conventional source such as a mango kernel. (2) Methods: Different power sonication conditions (120, 300, and 480 W) and sonication time (10, 20, and 30 min) were evaluated along with a control treatment (extracted by the wet milling method). (3) Results: Ultrasound-assisted extraction increases starch yield, with the highest values (54%) at 480 W and 20 min. A significant increase in the amylose content, water-holding capacity, oil-holding capacity, solubility, and swelling power of ultrasonically extracted starches was observed. Similarly, mango kernel starch (MKS) exhibited interesting antioxidant properties. The sol-gel transition temperature and pasting parameters, such as the breakdown viscosity (BD) and the setback viscosity (SB), decreased with ultrasound application; (4) Conclusion: indicating that ultrasound caused changes in physical, chemical, techno-functional, rheological, and pasting properties, depending on the power and time of sonication, so it can be used as an alternative starch extraction and modification technique, for example, for potential application in thermally processed food products such as baked goods, canned foods, and frozen foods.

Effects of selenium solution on the crystalline structure, pasting and rheological properties of common buckwheat starch

Selenium is an important element that affects human growth and development, and also affects the yield and quality of common buckwheat. In our study, two common buckwheat varieties were sprayed with different concentrations (0 g/hm², 5 g/hm², 20 g/hm²) of sodium selenite solution at the initial flowering period and the full flowering period, respectively, to determine the effects of selenium solution on the physicochemical properties of common buckwheat starch. With increasing selenium levels, the amylose content, peak viscosity, breakdown, relative crystallinity, pasting temperature and gelatinization enthalpy first decreased and then increased, while the transparency showed a trend of increasing and then decreasing. All samples exhibited a typical A-type pattern, while at high selenium level, the degree of short-range order of common buckwheat starches changed. From the rheological properties, it can be seen that the starch paste is dominated by elastic properties, while the low selenium treatment decreases the viscosity of the starch paste. These results showed that spraying different concentrations of selenium solutions at different periods significantly affected the physicochemical properties of common buckwheat starch.

Nitrogenous Fertilizer Levels Affect the Physicochemical Properties of Sorghum Starch

Nitrogen is a key factor affecting sorghum growth and grain quality. This experiment was designed to investigate the physicochemical properties of sorghum starch in four sorghum varieties (Liaoza 10, Liaoza 19, Jinza 31, and Jinza 34) under four nitrogen levels: 0 kg/ha urea (N1), 300 kg/ha urea as base fertilizer (N2), 300 kg/ha urea as topdressing at the jointing stage (N3), and 450 kg/ha urea as topdressing at the jointing stage (N4). The results showed that grain size and amylose content increased with increasing nitrogen fertilizer level, peaking at N3. The peak viscosity, final viscosity, gelatinization temperature, initial temperature, final temperature, and enthalpy value increased with the nitrogenous fertilizer level, peaking at N3. The application of nitrogen fertilizer at the jointing period significantly increased the above indicators. However, excess nitrogen at the jointing period (N4) can significantly reduce the above indicators, thus changing the physicochemical properties and structure of sorghum starch. Overall, nitrogen significantly affects the structure and physicochemical properties of sorghum starch.

Variations in the Multilevel Structure, Gelatinization and Digestibility of Litchi Seed Starches from Different Varieties

Litchi seed starches from six varieties, as compared with maize starch, were studied for their multilevel structures, thermal and digestion properties to understand the distinct feather of each variety and provide guidance for their utilization in multi-industries. The results showed different varieties of litchi seed starch shared similar appearances with granules in oval shape and with a smooth surface. Starch granules of all the varieties exhibited typical bimodal size distributions consisting of small (<40 μm) and large granules (40−110 μm), although their relative proportions were largely dependent on variety. Huaizhi had the largest D50 value, whilst Guiwei showed the lowest. All the litchi seed starches had A-type crystalline with relative crystallinity varying from 20.67% (Huaizhi) to 26.76% (Guiwei). Similarly, the semi-crystalline structure varied apparently with variety. As to the chain-length distribution, only slight differences were observed among varieties, except Huaizhi displayed apparently higher amylose content (34.3%) and Guiwei showed the lowest (23.6%). Significant differences were also present in the gelatinization properties. Huaizhi seed starch showed significantly higher gelatinization temperatures and lower enthalpy change than the others. The digestibility of cooked litchi seed starches was only slightly different among varieties, suggesting variety is not the most critical factor regulating the digestibility of cooked litchi seed starch.

Development and performance evaluation of hand-operated mango seed decorticator

Mango seed kernel, a by-product of mango fruit can be consumed as the safe food if properly processed. A hand operated mango seed decorticator was developed to substitute the unhygienic and unsafe existing method. The device consisted of four major sections such as frame support, feeding unit, sliding unit and decorticating unit. Provisions were made to position the seeds inside the seed holder and the splitting blades to penetrate and break open the stony endocarp along the cleavage. The performance of the machine was evaluated and was compared to that of traditional method. The device resulted in higher whole kernel recovery (85.95 ± 1.53%), decortication capacity (1.92 ± 0.04 kg h^-1) than traditional method with 58.37 ± 1.76% and 1.10 ± 0.09 kg h^-1, respectively. Traditional method incurred higher material loss with broken kernels making them unsafe for consumption if not processed quickly. Statistical analysis also indicated that the efficacy of traditional method was dependent on personal skill as there was operational variability in the data set with higher coefficient of variation. Therefore, the developed mango seed decorticator is expected to assist in utilization of mango kernel as safe food as well as to reduce the drudgery of the operation.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-021-05256-5.

Standardization of process protocol for isolation of starch from mango kernel and its characterization

BACKGROUND

The major by-products of mango processing are the seeds, which represent approximately 15-20% of the fruit. The process protocol for isolation of starch from mango kernel was standardized based on starch yield, starch purity and colour values using centrifugation and chemical method. Optimized starches obtained from both methods were further investigated for estimation of functional properties and were characterized through Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, differential scanning calorimetry and pasting properties analysis.

RESULTS

The slurry making of mango kernels with a solid-to-water ratio of 1:3 at a centrifugation frequency of 3 times was found to be the best among all the experimental combinations (solid-to-water proportion (1:2, 1:3 and 1:4, w/v) and centrifugation frequency (2, 3 and 4 times)) with a starch yield of 48.43 ± 1.08% and purity of 76.46 ± 0.83%. In the chemical method of starch isolation (washing was done with 0.1 mol L^-1 NaOH and 0.1 mol L^-1 HCl at three levels each), the sample treated with 60% (w/v) 0.1 mol L^-1 NaOH and 10% (w/v) 0.1 mol L^-1 HCl resulted in 36.50 ± 0.58% starch yield with a purity of 92.03 ± 0.87%. Among the functional properties, the chemically isolated starch showed significantly higher paste clarity (45.79 ± 2.36%) than starch obtained using the centrifugation process (12.50 ± 1.57%). The chemically isolated starch also exhibited better colour attributes, which were very close to those of laboratory-grade starch.

CONCLUSION

Detailed characterization studies inferred that both the starches possessed good functional, structural and thermal properties, indicating suitability for food and non-food applications. © 2021 Society of Chemical Industry.

Agricultural crop waste materials - A potential reservoir of molecules

Crop wastes are one of the agricultural wastes generated during the production and processing of food materials. Their generation is the other side of developmental activities. They are now becoming an alarming source of environmental pollution, leading to an unhealthy society. There is an urgent need to develop robust methods to utilize these types of wastes into beneficial compounds or materials. Many works are successfully done in these areas, and several strategies have been developed to produce biochemicals from biological wastes. In other words, value addition has been done to the crop waste materials. The chemicals like carbohydrates, minerals, proteins, and other compounds have been isolated from various crop residues. In this context, this article covers an overview of the crop wastes, chemicals isolated from them, their extraction methods, and the way forward to get the valuable chemicals.

Understanding how different modification processes affect the physiochemical, functional, thermal, morphological structures and digestibility of cardaba banana starch

In this study, starch was isolated from cardaba banana starch and was subjected to modification by heat-moisture treatment, citric acid, octenyl succinic anhydride, and sodium hexametaphosphate. Both the native and modified cardaba banana starches were examined for chemical, functional, pasting, thermal, morphological, structural, and antioxidant properties, as well as in vitro starch digestibility. Modification significantly influenced the properties of the cardaba banana starch. Cross-linking treatment improved the water, oil absorption, alkaline hydration capacity, swelling power, solubility and paste clarity of the starch. The final viscosity of the banana starch paste was increased alongside succinic anhydride modification which in turn enhanced the suitability of the starch in the production of high viscous products. Both FTIR spectra and X-ray diffractograms confirmed the starch had a C-type starch which was not affected by modification. Modification led to a decrease in relative crystallinity of the starch with succinylation having the maximum effect. The starch fractions; both SDS and RS significantly increased due to modification while the hydrolysis and glycemic index of the starch were significantly decreased by chemical modification. In conclusion, both physical and chemical modification of cardaba banana starch produced a starch that can serve as functional food or functional food ingredients.

Optimization of ultrasonic-assisted enzymatic extraction of kiwi starch and evaluation of its structural, physicochemical, and functional characteristics

A new ultrasound-assisted enzymatic extraction (UAEE) method of starch from kiwifruit was established and optimized using response surface methodology (RSM). Under optimal conditions (the pectinase-to-cellulase-to-papain ratio = 1:2:1 g/kg, solid/liquid ratio = 1:6.68, extraction pH = 5.23, ultrasound power = 300 W, and extraction temperature = 52 °C), the kiwi starch (KS) yield was about 4.25%, and the starch content of KS was 873.23 mg/g. Compared to other extraction methods, UAEE can obtain KS with high yield and purity with a shorter extraction time and less solvent and enzyme. The extracted KS has a low gelatinization enthalpy (8.02 J/g) and a high peak viscosity (7933 cP), with obvious particle properties and low adhesion. In addition, KS is rich in polyphenols, has strong antioxidant activity, and has higher contents of amylose starch (30.74%) and resistant starch (60.18%). This study established a novel and highly efficient method for KS extraction and suggest several possible applications for KS in the food industry.

Resistant Starch Contents of Starch Isolated from Black Longan Seeds

A large quantity of longan fruits (Dimocarpus longan Lour.) produced annually are processed into many products, one of which is black longan, from which the dried, dark-brown meat has been used medicinally in traditional medicine, while the starch-containing seeds are discarded. In this study, starch samples (BLGSs) were isolated from seeds of black longan fruits prepared using varied conditions. The in vitro digestibility was determined in comparison with those extracted from fresh (FLGS) and dried (DLGS) seeds. Scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR) spectroscopy were employed to evaluate the starch properties. The results showed that the yields of FLGS, DLGS, and BLGSs were 20%, 23%, and 16-22% w/w, respectively. SEM images showed starch granules of mixed shapes, with sizes up to 15 µm in all samples. XRD patterns confirmed an A-type crystallinity for FLGS and DLGS, with strong refraction peaks at 2θ = 15°, 17°, 18°, and 23°, while BLGSs also showed detectable peaks at 2θ = 10° and 21°, which suggested V-type structures. Thermal properties corroborated the changes by showing increases in peak gelatinization temperature (Tp) and enthalpy energy (ΔH) in BLGSs. The paste viscosity of BLGSs (5% w/w) decreased by 20-58% from that of FLGS. The FTIR peak ratio at 1045/1022 and 1022/995 cm-1 also indicated an increase in ordered structure in BLGSs compared to FLGS. The significant increase in the amounts of slowly digestible starch (SDS) and resistant starch (RS) in BLGSs compared to FLGS, especially at a prolonged incubation time of 20 (4.2×) and 30 days (4.1×), was proposed to be due to the heat-induced formation of starch inclusion with other components inside the seed during the black longan production process. Thus, black longan seed could be a new source of starch, with increased RS content, for potential use in the food and related industries.

Characterization of underutilized root starches from eight varieties of ramie (Boehmeria nivea) grown in China

Ramie root is an underutilized starch source. In this study, eight ramie varieties were investigated for starch properties. Starch content ranged from 18.6% to 50.1% in dry root. Starches from different varieties showed similar morphology including ellipsoidal, spherical and truncated granules with size D[4,3] from 10.1 to 14.1 μm. Starch had amylose content from 20.8% to 28.5%. All ramie varieties had B-type starches with relative crystallinity from 24.8% to 27.1%, ordered degree from 0.724 to 0.897 and lamellar thickness from 9.1 to 9.6 nm. Starches had gelatinization peak temperature from 70.5 to 73.8 °C and enthalpy from 14.9 to 15.8 J/g. Starches had swelling power and water solubility from 27.9 to 31.9 g/g and from 11.7% to 15.5%, respectively, at 95 °C, and exhibited different pasting properties with breakdown viscosity from 36 to 377 mPa s and setback viscosities from 1295 to 1863 mPa s. Starch pastes exhibited pseudoplastic behavior and different rheological properties. Native, gelatinized and retrograded starches had resistant starch from 81.7% to 83.9%, from 1.7% to 5.1% and from 5.6% to 13.3%, respectively. The eight varieties were divided into 3 groups according to starch properties. This study is helpful for selecting suitable ramie variety as starch source.

Rheological, thermal, and structural properties of high-pressure treated Litchi (Litchi chinensis) kernel starch

Starch isolated from litchi kernel was subjected to high-pressure (HP) treatment at selected pressures (300, 450 and 600 MPa) for 10 min, and evaluated for its rheological, morphological, thermal and structural properties. The amylose content of native litchi kernel starch (LKS) was 17.4%, which increased significantly upon pressurization. The temperature sweep test of the untreated starch sample resulted in the peak G' and G″ values of 3417 and 283 Pa, respectively, and those values decreased after pressurization. Oscillatory rheological measurements showed the frequency dependency of tested starch pastes. Furthermore, the mechanical rigidity of the starch pastes improved with pressure treatment. Morphological studies revealed that starch granule structure remained intact after pressurization; however, pressure >450 MPa resulted in surface roughness and small cavities. HP treatment significantly influenced thermal properties of LKS, in particular at 450 and 600 MPa, where a significant drop in the transition temperatures and enthalpy values were recorded. The HP-treated starch samples exhibited distinct X-ray diffraction pattern of native LKS i.e. the blend of A- and B-type allomorphs with a predominating A-type crystalline structure. Upon pressure treatment, the disappearance of 2θ peak at 5.6° and significant changes in peak intensities confirmed the structural change in the starch matrix.

Physicochemical properties of a new starch from ramie (Boehmeria nivea) root

A new starch was isolated from ramie root, and its physicochemical properties were investigated. Ramie dry root contained 45.9% starch. Starch had truncated, ellipsoidal, and spherical granule shapes with size from 7 to 30 μm and D[4,3] about 14.1 μm. Starch contained 38.9% apparent amylose content and 22.4% true amylose content, exhibited B-type crystallinity, and had 26.6% relative crystallinity, 0.82 ordered degree, and 9.2 nm lamellar thickness. Starch had 71.8 °C gelatinization peak temperature and 15.6 J/g gelatinization enthalpy, and exhibited 31.4 g/g swelling power and 17.1% water solubility at 95 °C. Starch had peak, hot, breakdown, final, and setback viscosities at 3048, 2768, 279, 4165, and 1397 mPa s, respectively, and showed peak time at 4.36 min and pasting temperature at 75.0 °C. The native, gelatinized, and retrograded starches contained 15.1%, 94.0%, and 86.5% rapidly digestible starch and 83.3%, 4.0%, and 10.7% resistant starch, respectively. Compared with potato and rice starches, ramie starch was somewhat similar to potato starch but significantly different from rice starch in starch component, crystalline structure, and functional properties. Therefore, ramie starch exhibited the potential to be used as a thickening agent, resistant-digesting food additive, and alternative to potato starch in food and nonfood industries.

Antimicrobial Activity and GC-MS Profile of Copaiba Oil for Incorporation into Xanthosoma mafaffa Schott Starch-Based Films

The present study evaluated the effect of the incorporation of copaiba oil, in direct and in microencapsulated form, into films based on Xanthosoma mafaffa Schott starch. Initially, the characterization of copaiba oil by gas chromatograph coupled with mass spectrometry (GC-MS) and its antimicrobial activity against gram-positive and gram-negative bacteria was performed. The films were produced by the casting technique and characterized in relation to physical, chemical, structural, and antimicrobial activity. Sesquiterpenes, mainly β-caryophyllene, were the predominant compounds in copaiba oil, showing antimicrobial activity against B. subtilis and S. aureus. The films showed forming capacity, however, was observed a decrease in solubility and revealed an increase in hydrophobic characteristics. However, the oil reduced the tensile strength and elongation, while the microcapsules did not influence the mechanical properties in comparison to the control film. From microstructure analysis, changes in the films roughness and surface were observed after the addition of oil both directly and in microencapsulated form. Films incorporated with microparticles were able to inhibit the gram-positive bacteria tested, forming inhibition zones, indicating that the encapsulation of copaiba oil was more efficient for protecting bioactive compounds from the oil, suggesting the possible application of mangarito starch-based films incorporated with copaiba oil as biodegradable packaging.

Structural, pasting and thermal properties of common buckwheat (Fagopyrum esculentum Moench) starches affected by molecular structure

Common buckwheat starch (CBS) has extensive using value in the human diet. In this study, the molecular structure and physicochemical properties of CBS isolated from five cultivars collected from three regions of China were studied. Variations in molecular structure, crystalline structure, complexity, water solubility (WS), swelling power (SP), pasting properties, and thermal characteristics were recorded among the starches. The CBS had both similarities and differences in its properties by comparison with maize starch (MS) and potato starch (PS). The average molecular weight (M_W) and amylopectin average chain length (ACL) of CBS ranged from 3.86 × 10⁷ g/mol to 4.68 × 10⁷ g/mol and from 21.29% to 22.68%, respectively. CBS and MS were divided into one subgroup and showed typical A diffraction patterns, while PS was divided into two subgroups and exhibited a typical B polymorphic pattern. The WS and SP of all the starches significantly increased with increasing temperature and had great variation at 70 °C and 90 °C. Pearson's correlation analysis showed that the molecular structure of starches greatly affected the physicochemical properties. This study revealed that the physicochemical properties of CBS could be affected by the molecular structures.

Effect of Pretreatment Methods on Enzymatic Kinetics of Ungelatinized Cassava Flour Hydrolysis

The energy-saving glucose production process from starchy sources was developed by replacing high-temperature, liquid-phase by low-temperature, solid-phase. Therefore, the enzymatic hydrolysis under gelatinization temperature at very high gravity (≥300 g.L−1) of starchy substrates presents as an emerging technology. This study focused on the hydrolysis kinetics of cassava flour affected by different pretreatment methods. Cassava flour (dried, milled) was prepared in acetate buffer (pH 4.2) with starch concentration ranging from 10–30% (w/w). The mash was then pre-treated by three different methods for 30 min using heating (30, 40, 50 °C), enzyme (Viscozyme L 0.1% w/w) and microwave (3 × 20 s at 800 W). The suspension was then hydrolyzed with Stargen 002 (0.2% w/w) at 30 °C for 48 h. The enzyme adsorption kinetics was described by the Langmuir isotherm equation. The pretreatments at 50 °C and with enzyme resulted in the highest efficiency with the hydrolysis yield ranging from 76–79% after 48 h. The hydrolysis yield decreased to 67% (using microwave), 66% (at 45 °C), 61% (at 40 °C) and 59% (at 30 °C). The linear relationship between enzyme adsorption and produced glucose was demonstrated. The kinetics of glucose production was fitted by an empirical equation (analogy with Michaelis-Menten model) and allowed predicting the maximum hydrolysis yield.