Design, characterization and digestibility of β-carotene-loaded emulsion system stabilized by whey protein with chitosan and potato starch addition

The physicochemical properties and gastrointestinal fate of β-carotene-loaded emulsions and emulsion gels were examined. The emulsion was emulsified by whey protein isolate and incorporated with chitosan, then the emulsion gels were produced by gelatinizing potato starch in the aqueous phase. The rheology properties, water distribution, and microstructure of emulsions and emulsion gels were modulated by chitosan combination. A standardized INFOGEST method was employed to track the gastrointestinal fate of emulsion systems. Significant changes in droplet size, zeta-potential, and aggregation state were detected during in vitro digestion, including simulated oral, stomach, and small intestine phases. The presence of chitosan led to a significantly reduced free fatty acids release in emulsion, whereas a slightly increasing released amount in the emulsion gel. β-carotene bioaccessibility was significantly improved by hydrogel formation and chitosan addition. These results could be used to formulate advanced emulsion systems to improve the gastrointestinal fate of hydrophobic nutraceuticals.

Fine molecular structure and digestibility changes of potato starch irradiated with electron beam and X-ray

The change of digestibility of starch irradiated with different types from the perspective of fine structure is not well understood. In this work, the change of internal structure, molecular weight and chain-length distribution, helical structure, lamellar structure, fractal structure and digestibility of native and treated potato starch with electron beam and X-ray was analyzed. Two irradiations caused the destruction of internal structure, the disappearance of growth rings and increase of pores. Irradiation degraded starch to produce short chains and to decrease molecular weight. Irradiation increased double helical content and the thickness and peak area of lamellar structure, resulting in the reorganization of amylopectin and increase of structure order degree. The protected glycosidic linkages increased starch resistance to hydrolase attack, thereby enhancing the anti-digestibility of irradiated starch. Pearson correlation matrix also verified the above-mentioned results. Moreover, X-ray more increased the anti-digestibility of starch by enhancing ability to change fine structure.

GBSS mutations in an SBE mutated background restore the potato starch granule morphology and produce ordered granules despite differences to native molecular structure

Potato starch with mutations in starch branching enzyme genes (SBEI, SBEII) and granule-bound starch synthase gene (GBSS) was characterized for molecular and thermal properties. Mutations in GBSS were here stacked to a previously developed SBEI and SBEII mutation line. Additionally, mutations in the GBSS gene alone were induced in the wild-type variety for comparison. The parental line with mutations in the SBE genes showed a ∼ 40 % increase in amylose content compared with the wild-type. Mutations in GBSS-SBEI-SBEII produced non-waxy, low-amylose lines compared with the wild-type. An exception was a line with one remaining GBSS wild-type allele, which displayed ∼80 % higher amylose content than wild-type. Stacked mutations in GBSS in the SBEI-SBEII parental line caused alterations in amylopectin chain length distribution and building block size categories of whole starch. Correlations between size categories of building blocks and unit chains of amylopectin were observed. Starch in GBSS-SBEI-SBEII mutational lines had elevated peak temperature of gelatinization, which was positively correlated with large building blocks.

Effect of pre-treatments and frying conditions on the formation of starch-lipid complex in potato starch chips during deep-frying process

This study examined the influence of various pretreatment methods, frying durations, and temperatures, as well as the type of frying oil, on the formation and structure of starch-lipid complexes in fried potato chips. Potato starch was processed into dough, sliced, and subjected to deep frying following various pretreatments. Structural analysis showed that steaming as a pretreatment facilitated the generation of V-type starch-lipid complexes, whereas resistant starch type III (RS3) materialized in the desiccated samples instead of the anticipated complexes. The rate of starch-lipid complex formation initially surged but subsequently declined as treatment time increased. A reduction in treatment temperature from 190 °C to 170 °C was conducive to complex formation. Moreover, the maximum relative crystallinity (19.74 %) and ΔH value (7.76 J/g) were recorded for potato starch slices pretreated by steaming and frying in palm oil. Rapeseed oil, which is rich in unsaturated fatty acids (89.98 %), inhibits complex formation. The study concludes that pretreatment methods exert a substantial effect on the formation of starch-lipid complexes and that extended frying duration and elevated temperature may reduce this formation. Oils with longer-chain fatty acids and a lower degree of unsaturation were favorable for complex formation.

Potato starch/naringenin complexes for high-stability Pickering emulsions: Structure, properties, and emulsion stabilization mechanism

In this study, potato starch (PS)/naringenin (NAR) complex was prepared, and its properties and emulsification behavior were evaluated. The experimental results demonstrated that NAR successfully formed a complex with PS molecules through hydrogen bonds and other non-covalent interactions. The emulsifying capacity (ROV) of PS/NAR complex with 16 % composite ratio was 0.9999, which was higher than PS (ROV = 0.3329) (p < 0.05). Based on particle property analysis and molecular dynamics simulation, the mechanism of improving the emulsification performance might be the action of the benzene ring of NAR and intermolecular hydrogen bonding. In addition, the stability of the Pickering emulsions with PS/NAR complexes as emulgators was significantly improved. The emulsifying and rheological behavior of starch-based Pickering emulsions could be adjusted by changing the proportion of the complexes. Results demonstrated that the PS/NAR complexes might be a prospective stabilizer of Pickering emulsions based on starch material and might expand the use of PS in edible products.

Bioinformatics and functional selection of GH77 4-α-glucanotransferases for potato starch modification

4-α-glucanotransferases (4αGTs, EC 2.4.1.25) from glycoside hydrolase family 77 (GH77) catalyze chain elongation of starch amylopectin chains and can be utilized to structurally modify starch to tailor its gelation properties. The potential relationship between the structural design of 4αGTs and functional starch modification is unknown. Here, family GH77 was mined in silico for enzyme candidates based on sub-grouping guided by Conserved Unique Peptide Patterns (CUPP) bioinformatics categorization. From + 12,000 protein sequences a representative set of 27 4αGTs, representing four different domain architectures, different bacterial origins and diverse CUPP groups, was selected for heterologous expression and further study. Most of the enzymes catalyzed starch modification, but their efficacies varied substantially. Five of the 4αGTs were characterized in detail, and their action was compared to that of the industrial benchmark enzyme, Tt4αGT (CUPP 77_1.2), from Thermus thermophilus. Reaction optima of the five 4αGTs ranged from ∼40-60 °C and pH 7.3-9.0. Several were stable for a minimum 4 h at 70 °C. Domain architecture type A proteins, consisting only of a catalytic domain, had high thermal stability and high starch modification ability. All five novel 4αGTs (and Tt4αGT) induced enhanced gelling of potato starch. One, At4αGT from Azospirillum thermophilum (CUPP 77_2.4), displayed distinct starch modifying abilities, whereas T24αGT from Thermus sp. 2.9 (CUPP 77_1.2) modified the starch similarly to Tt4αGT, but slightly more effectively. T24αGT and At4αGT are thus interesting candidates for industrial starch modification. A model is proposed to explain the link between the 4αGT induced molecular modifications and macroscopic starch gelation.

Structural analysis of potato starch transformation during high-energy ball-milling: Oxygen and humidity content effects

High Energy Ball-Milling (HEBM) modifies starchs' granule morphology, physicochemical properties, and chemical structure. However, understanding how the HEBM changes the starch chemical structure is necessary to control these modifications. Therefore, this study aimed to investigate the changes in potato starch's long- and short-range molecular order during HEBM at different environmental conditions such as oxygen (Air) and humidity content. Due to the correlation between the starch modification and the energy supplied (Esupp) by the HEBM, Burgio's equation was used to calculate this energy. The starch transformation was followed by X-ray diffraction, Fourier Transform-Infrared Spectroscopy, and Raman spectroscopy. A Principal Component Analysis (PCA) was conducted to reduce the HEBM variables. PAC analysis demonstrated that the different oxygen-humidity conditions do not affect the HEBM of potato starch. Based on the starch chemical structure transformation correlated with Esupp during HEBM, four stages were observed: orientation, modification, mechanolysis, and over-destruction. It was identified for the first time that at low milling energy (<1.5 kJ/g, orientation stage), the glycosidic rings change their orientation, and starch-water interaction increases while the starch's organization reduces. Ergo, the potato starch could be more susceptible to chemical modifications during the first two stages.

Effects of cation valence on swelling power, solubility, pasting, gel strength characteristics of potato starch

The objective of this study was to investigate the effects of monovalent, divalent and trivalent cations on the physicochemical properties of potato starch. Cations decreased the water absorption in potato starch granules to cause lower swelling power, especially 0.02-0.04 mmol/g Fe3+ or 0.01-0.04 mmol/g Al3+, but 0.01 mmol/g trivalent cation led more amylose dissolving into the water to cause higher solubility. High concentration of divalent or trivalent cations markedly decreased the viscosity in potato starch paste during further heating and cooling, resulting in the decreases of the trough and finial viscosity, especially 0.04 mmol/g Fe3+. Higher valence of cations decreased the gel strength in potato starch, especially 0.02-0.04 mmol/g Fe3+ or Al3+. Higher valence of cations decreased the starch gel binding with the water and caused lower water holding capacity. In general, a higher valence of cations caused more changes in the physicochemical characteristics of potato starch.

The multi-scale structure changes of γ-ray irradiated potato starch to mitigate pasting/digestion properties

The comprehensive understanding of multi-scale structure of starch and how the structure regulates the pasting/digestion properties remain unclear. This work investigated the effects of γ-ray irradiation with different doses on multi-scale structure and pasting/digestion properties of potato starch. Results indicated that γ-ray at lower doses (<20 kGy) had little effect on micromorphology of starch, increased mainly the amylose content and the thickness of amorphous region while decreased crystallinity, double helix content and lamellar ordering. With the increase of dose, the internal structure of large granules was destroyed, resulting in the depolymerization of starch to form more short-chains and to reduce molecular weight. Meanwhile, amylose content decreased due to the depolymerization of amylose. The enhanced double helix content, crystallinity, lamellar ordering and structural compactness manifested the formation of the thicker and denser starch structure. These structure changes resulted in the decreased viscosity, the increased stability and anti- digestibility of paste.

Development, characterization and application of starch-based film containing polyphenols of piper betle L. waste in chicken meat storage

The current study aimed to develop a sustainable solution to extend the shelf life of chicken meat by developing starch-based functional film embedded with polyphenolic extract of waste petioles of betel leaf (BLP). The results showed that loading of the extract significantly (p < 0.05) improved flexibility, thickness, water solubility, DPPH radical scavenging activity, and UV light protection ability by enhancing intermolecular interactions among potato starch, guar gum, and the extract. The developed film showed optimum mechanical and water barrier properties at a 4% BLP extract concentration computed through TOPSIS method (A multi-criteria decision-making approach). During the shelf life study, the extract embedded film maintained the quality of chicken meat for up to 12 days at refrigerated temperature. Biodegradation time of the extract-blended films was considerably decreased to 14 days from 28 days for the native film, indicating suitable alternative to non-biodegradable film for storing the raw meat.

Physicochemical properties of different size fractions of potato starch cultivated in Highland China

Location influences the properties of potato starch. Potato starch granules cultivated in highland of China were separated into three fractions according to the sedimentation time: large- (∼81 μm, large fraction potato starch, LFPS), medium- (∼28 μm, medium fraction potato starch, MFPS), and small-size (∼15 μm, small fraction potato starch, SFPS) fractions. SFPS showed a spherical shape, MFPS showed an ellipsoid shape and LFPS showed an elongated shape. The three fractions showed the similar XRD patterns, while the relative crystallinity decreased with the decrease of granule size (LFPS 23.61%, MFPS 20.74% and SFPS 20.48%). The water solubility was positively corelated with the granule size, while the swelling power showed a negative relationship with the granule size. For the rheological properties, all the three fractions showed a shear-shinning behavior; and SFPS had the highest peak temperature. However, the MFPS showed the lowest storage modulus during the temperature sweep. The granule size didn't influence the nutritional properties of potato starch and LFPS had the highest slowly digestible starch (SDS) (83.77%) and resistant starch (RS) (13.66%) contents. Some of the properties are different from the previous studies.

Effects of zucchini polysaccharide on pasting, rheology, structural properties and in vitro digestibility of potato starch

Zucchini polysaccharide (ZP) has a unique molecular structure and a variety of biological activities. This study aimed to evaluate the effects of ZP (1, 2, 3, 4 and 5 %, w/w) on the properties of potato starch (PS), including pasting, rheological, thermodynamic, freeze-thaw stability, micro-structure, and in vitro digestibility of the ZP-PS binary system. The results showed that the appearance of ZP significantly reduced the peak, breakdown, final and setback viscosity and prolonged the pasting temperature of PS, whereas increased the trough viscosity. The tests of rheological showed that ZP had a damaging effect on PS gels. Meanwhile, the results of thermodynamic and Fourier transform infrared exhibited that the presence of ZP significantly retarded the retrogradation of PS, especially at a higher levels. The observation of the microstructure exhibited that ZP significantly altered the microscopic network structure of the PS gels, and ZP reduced the formation of the gel structure. Besides, ZP postponed the retrogradation process of PS gels. Moreover, ZP weakened the freeze-thaw stability of the PS gel. Furthermore, ZP also can decrease the digestibility and estimated glycemic index (eGI) value of PS from 86.04 % and 70.89 to 77.67 % and 65.22, respectively. Simultaneously, the addition of ZP reduced the rapidly digestible starch content (from 25.09 % to 16.59 %) and increased the slowly digestible starch (from 24.99 % to 26.77 %) and resistant starch content (from 49.92 % to 56.64 %). These results have certain guiding significance for the application of ZP in starch functional food.

Combined effect of heating temperature and content of pectin on the textural properties, rheology, and 3D printability of potato starch gel

Three-dimensional (3D) printing is one of the emerging techniques which fabricates customized foods with desired sensory characteristics. Rheological properties of 3D printing materials are vitally important in printability which govern the flowability and structural stability. Due to its unique gel-forming characteristics, potato starch has been extensively used in myriad food applications, such as 3D printing. However, little attention has been paid to the combined effect of heating temperature and pectin addition on the properties of potato starch gels. Thus, this study investigated the impact of different pectin contents (1, 1.5, and 2 %) on printability and the rheological and textural properties of potato starch gels heated at different temperatures (70, 80, and 90 °C). The gel heating temperature governs pectin-driven modifications in potato starch gels. Pectin addition increased the 3D printability, viscosity, storage modulus, hardness, gumminess, and springiness of starch gel at higher temperatures (80 °C and 90 °C). In contrast, at lower temperatures (70 °C), pectin addition decreased printability, viscosity, storage modulus, hardness, gumminess, and springiness. Therefore, the gel heating temperature influences the impact of pectin on printability, rheology, and textural properties. Accordingly, the combined effects of pectin and heating temperature should be considered in pectin-based 3D food-printing ink formulations.

Interaction between potato starch and barley β-glucan and its influence on starch pasting and gelling properties

The interactions between potato starch (PtS) and barley β-glucan (BBG) were investigated by preparing PtS-BBG mixtures, and the pasting, rheological, gelling and structural properties were evaluated. Rapid viscosity analysis suggested that BBG reduced the peak and breakdown viscosity, while increasing the setback viscosity of PtS. PtS-12%BBG showed the lowest leached amylose content (12.02 ± 0.36 %). The particle size distribution pattern of PtS was not changed with the addition of BBG, and the median diameter of PtS-12%BBG (88.21 ± 0.41 μm) was smaller than that of PtS (108.10 ± 6.26 μm). Rheological results showed that PtS and PtS-BBG gels exhibited weak gel behaviors, and BBG could remarkably affect the elastic and viscous modulus of PtS gels. Textural analysis suggested that the strength and hardness of PtS gels were increased when few BBG (<6 %, w/w) was present in the system. BBG improved the freeze-thaw stability of PtS gels. Structural analysis indicated that hydrogen bonds were the main force in the PtS-BBG systems. These results indicated that BBG interacted with starch via hydrogen bonds, which delayed starch gelatinization and improved gelling properties of PtS gels. Overall, this study gained insights into starch-polysaccharide interactions and revealed the possible applications of BBG in food processing.

Regulating the physicochemical, structural characteristics and digestibility of potato starch by complexing with different phenolic acids

The effects of ferulic acid (FA), protocatechuic acid (PA), and gallic acid (GA) on the physicochemical characteristics, structural properties, and in vitro digestion of gelatinized potato starch (PS) were investigated. Rapid viscosity analysis revealed that the gelatinized viscosity parameters of PS decreased after complexing with different phenolic acids. Dynamic rheology results showed that phenolic acids could reduce the values of G' and G″ of PS-phenolic acid complexes, demonstrating that the addition of phenolic acids weakened the viscoelasticity of starch gel. Fourier-transform infrared spectra and X-ray diffraction results elucidated that phenolic acids primarily reduced the degree of short-range ordered structure of starch through non-covalent interactions. The decrease in thermal stability and the more porous microstructure of the complexes confirmed that phenolic acids could interfere with the gel structure of the starch. The addition of different phenolic acids decreased the rapidly digestible starch (RDS) content and increased the resistant starch (RS) content, with GA exhibiting the best inhibitory capacity on starch in vitro digestibility, which might be associated with the number of hydroxy groups in phenolic acids. These results revealed that phenolic acids could affect the physicochemical characteristics of PS and regulate its digestion and might be a potential choice for producing slow digestibility starch foods.

A novel efficient wet process for preparing cross-linked starch: Impact of urea on cross-linking performance

Although wet processes are promising for preparing cross-linked starch, they are currently challenged by lower cross-linking efficiency and the requirement of large amounts of salts. Herein, an efficient and greener wet process was proposed, in which the cross-linking performance between sodium hexametaphosphate (SHMP) and starch was enhanced with the aid of urea. The maximum degree of substitution (DS) of the urea-phosphorylated cross-linked starch (UPCS) was 0.040 at 35 °C, while that of the conventional phosphorylated cross-linked starch (CPCS) was 0.031 at 45 °C. Compared with CPCS, the maximum DS of UPCS was elevated by 29.03 %, but its optimum cross-linking temperature was reduced by 10 °C, indicating that the cross-linking efficiency of this novel wet process was greatly improved by urea. The structural difference between UPCS and CPCS was confirmed by using a series of techniques including 31P NMR and 13C NMR. Zeta potential results suggested that urea may promote starch cross-linking by preventing the closure of active sites through hydrophobic interactions. Due to the structural reinforcement of starch by urea, UPCS showed better thermal stability, water resistance, acid and alkali resistance, and steady shear tolerance properties. This study provides a facile wet process for the fabrication and application of cross-linked starch materials.

Biomacromolecule assembly of soy glycinin-potato starch complexes: Focus on structure, function, and applications

The effect of the cross-linking mechanism and functional properties of soy glycinin (11S)-potato starch (PS) complexes was investigated in this study. The results showed that the binding effecting and spatial network structure of 11S-PS complexes via heated-induced cross-linking were adjusted by biopolymer ratios. In particular, 11S-PS complexes with the biopolymer ratios of 2:15, had a strongest intermolecular interaction through hydrogen bonds and hydrophobic force. Moreover, 11S-PS complexes at the biopolymer ratios of 2:15 exhibited a finer three-dimensional network structure, which was used as film-forming solution to enhance the barrier performance and mitigate the exposure to the environment. In addition, the 11S-PS complexes coating was effective in moderating the loss of nutrients, thereby extending their storage life in truss tomato preservation experiments. This study provides helpful to insights into the cross-linking mechanism of the 11S-PS complexes and the potential application of food-grade biopolymer composite coatings in food preservation.

Extraction and characterization of starch from low-grade potatoes and formulation of gluten-free cookies containing modified potato starch

Potatoes are among the leading staple crops due to nutritional value and high demand. The undersized and damaged potatoes are considered low grade and mainly dumped as a waste or used in animal feed. The study aimed to extract starch from low grade potatoes, its modification to improve the starch properties and formulation of gluten free cookies using modified starch (MS). The starch was extracted from low-grade potatoes of three varieties known as Asterix, Kruda and Mosaic, using the water steeping method. The native starch (NS) was modified using lintnerization and repetitive autoclaving. MS contains high amylose content which is associated with health benefits. NS and MS were characterized for amylose content, color attributes, granular morphology, water solubility index (WSI), water absorption index (WAI), thermogravimetric analysis (TGA) and Fourier transform infrared spectrometer (FTIR) analysis. Gluten-free cookies were formulated by adding potato NS and MS. The cookies were characterized by sensory evaluation, proximate and textural analysis. The starch yield extracted from three different varieties of potatoes i.e. Asterix, Kruda, Mosaic was 11.53%, 11.32% and 11.24%, respectively. The amylose content of potato starch was significantly (p < 0.05) increased for all varieties (33.61-37.74%) after modification of NS, which was in the range of 25.71-26.60% for different potato varieties. The granules of MS were observed as amorphous structures in comparison to NS granules with smooth surfaces. The addition of MS significantly (p < 0.05) decreased the hardness of the cookies in comparison to NS. Overall, no significant difference was observed in the sensory attributes of control, NS and MS containing cookies. Therefore, in comparison to other dietary fibers, MS can be used as a functional ingredient in food products without compromising the texture and sensory attributes.

Development of starch-based amorphous CoOx self-supporting carbon aerogel electrocatalyst for hydrogen evolution

Hydrogen energy is turning into a major research topic in this complex and changing world. In recent years, more and more research has been done on transition metal oxides and biomass composites. In this study, potato starch and amorphous cobalt oxide were assembled into carbon aerogel by sol-gel method and high-temperature annealing (CoOx/PSCA). The connected porous structure of the carbon aerogel is conducive to HER mass transfer, and its structure can avoid the agglomeration of transition metals. It also has great mechanical properties and can be directly used as a self-supporting catalyst for electrolysis with 1 M KOH for hydrogen evolution, which showed excellent HER activity and yielded the effective current density of 10 mA cm^-2 at 100 mV overpotential. Electrocatalytic experiments further showed that the better performance of CoOx/PSCA for HER can be attributed to the high electrical conductivity of carbon and the synergistic effect of unsaturated catalytic sites on the amorphous CoOx cluster. The catalyst comes from a wide range of sources, is easy to produce, and has good long-term stability, so it can be used in large-scale production. This paper provides a simple and easy method to make biomass-based transition metal oxide composites for electrolyzing water to produce hydrogen.

Effect of low temperature extrusion-modified potato starch addition on properties of whole wheat dough and texture of whole wheat youtiao

In this study, low temperature extrusion-modified potato starch (MPS) was added to improve properties of whole wheat dough and textural quality of resulted youtiao. Extrusion temperature (60, 90 ℃) and barrel moisture content (30, 42 and 54%) were set as test variables. The results suggested that the low temperature extrusion processing caused moderate gelatinization and improved gel-forming properties of potato starch. MPS addition decreased the setback by up to 46%, and enhanced the viscoelasticity of whole wheat dough significantly. Compared to the whole wheat-based youtiao, the addition of 10% MPS decreased the hardness by up to 72%, and increased the springiness and specific volume by 32% and 22%, respectively. The addition of MPS prepared at lower extrusion temperature (60 ℃) and moderate moisture content (42%) resulted in the optimum textural qualities of whole wheat youtiao. This study will help better understand the role of MPS in whole wheat-based food product.

The effect of thiolation process with l-cysteine on amylolysis efficiency of starch-cysteine conjugate by α-amylase

l-Cysteine (l-Cys) pre-treatment at two concentrations (150 mg/kg; PC1 and 300 mg/kg; PC2) on potato starch was conducted to produce starch-cysteine conjugates. Afterward, the effect of α-amylase on starch digestibility of potato native (PE) and starch-cysteine conjugates (PC1E and PC2E) were examined. Thiolation not only damaged starch according to the formation of pore and blister-like spots on the surface of starch granules, but also provided the functional group to immobilize α-amylase. Starch-cysteine conjugates showed a significantly greater degree of hydrolysis 24.1 % (PC1E) and 36.5 % (PC2E) in comparison with (16.8 %; PE). Destroying the granules integrity were accompanied with decreased crystallinity from 37.7 % to 33.1 % (PC1), 31.1 % (PC2), 27.6 % (PC1E) and 22.4 % (PC2E) with increasing thiol content (%) on surface from 2.3 %; PC1 to 3.4 %; PC2. The ratio of 1047/1022 cm^{- 1} reduced from 1.112 (native potato starch) to 0.974 (PC1E) and 0.867 (PC2E) after being subjected to α-amylase. Additionally, substantially low pasting viscosities (determined by RVA) along with the thermal properties (determined by DSC) of starch-cysteine conjugates treated with α-amylase could confirm the degradation of molecular structures containing low swelling power.

Development of intelligent and active potato starch films based on purple corn cob extract and molle essential oil

The present study aims to develop of an active and "intelligent" film that uses potato starch as a polymeric matrix, anthocyanins from purple corn cob as a natural dye, and molle essential oil as an antibacterial compound. The color of anthocyanin solutions is pH-dependent, and the developed films shows a visual color change from red to brown after immersion in solutions with pH values ranging from 2 to 12. SEM and FTIR analyses suggested that anthocyanins have favorable dispersibility and good compatibility with the starch-glycerol matrix. The study found that both anthocyanins and molle essential oil significantly enhanced the ultraviolet-visible light barrier performance; moreover, tensile strength, elongation at break, and elastic modulus reached values of 3.21 MPa, 62.16 %, and 12.87 MPa, respectively. The biodegradation rate in vegetal compost also accelerated during the three-week period, achieving a weight loss of 95 %. Moreover, the film presented an inhibition halo for Escherichia coli, indicating its antibacterial activity. The results suggest that the developed film has the potential to be used as food-packaging material.

Characterizing digestibility of potato starch with cations by SEM, X-ray, LF-NMR, FTIR

Cations can combine with starch and alter its physicochemical characteristics. The addition of cations may influence the in vitro digestion of potato starch. Scanning electron microscopy, X-ray diffraction, low-field nuclear magnetic resonance, and Fourier transform infrared spectroscopy were used to measure the microstructure, relative crystallinity, water distribution, and interaction of potato starch with cations and characterize its digestibility. The results showed that all cations decreased rapidly digestible starch (RDS) at a low concentration but increased the RDS with the addition of cations, especially trivalent cations. However, the resistant starch (RS) had the opposite trend. All cations increased the relative crystallinity of potato starch, except Ca²⁺. Fe³⁺, and Al³⁺ markedly decreased the mobility and hydrogen bonds in potato starch. In general, the addition of cations influenced the retrogradation of potato starch, resulting in a change in its digestibility.

Structural characterization of potato starch modified by a 4,6-α-glucanotransferase B from Lactobacillus reuteri E81

The recent reports have revealed that increase in amount of α-1,6 linkages by modification of potato starch with enzyme (glycosyltransferases) treatment gains slowly digestible properties to the starch; however, the formation of new α-1,6-glycosidic linkages diminish the thermal resistance of the starch granules. In this study, a putative GtfB-E81, (a 4,6-α-glucanotransferase-4,6-αGT) from L. reuteri E81 was firstly used to produce a short length of α-1,6 linkages. NMR results revealed that external short chains mostly comprised of 1-6 glucosyl units were newly produced in potato starch, and the α-1,6 linkage ratio was significantly increased from 2.9 % to 36.8 %, suggesting that this novel GtfB-E81 might have potentially an efficient transferase activity. In our study, native and GtfB-E81 modified starches showed fundamental similarities with respect to their molecular properties and treatment of native potato starch with GtfB-E81 did not remarkably change thermal stability of the potato starch, which seems to be very prominent for the food industry given the significantly decreased thermal stability results obtained for the enzyme modified starches reported in the literature. Therefore, the results of this study should open up emerging perspectives for regulating slowly digestible characteristics of potato starch in future studies without a significant change in the molecular, thermal, and crystallographic properties.

Comparative investigation of the effects of electron beam and X-ray irradiation on potato starch: Structure and functional properties

Electron beam (particle radiation) and X-ray (electromagnetic radiation) without radioisotope in the application of material modification have received increasing attention in the last decade. To clarify the effect of electron beam and X-ray on the morphology, crystalline structure and functional properties of starch, potato starch was irradiated using electron beam and X-ray at 2, 5, 10, 20 and 30 kGy, respectively. Electron beam and X-ray treatment increased the amylose content of starch. The surface morphology of starch did not change at lower doses (< 5 kGy), but starch granules were aggregated with the increase of doses. All treatments decreased crystallinity, viscosity and swelling power but increased solubility and stability properties. The effects of electron beam and X-ray on the starch had a similar trend. Unlike X-ray, electron beam destructed the crystallinity of starch to a lesser extent, thereby increasing thermal stability and freeze-thaw stability. Furthermore, X-ray irradiation at higher doses (> 10 kGy) resulted in outstanding anti-retrogradation properties of starch compared with electron beam treatment. Thus, particle and electromagnetic irradiation displayed an excellent ability to modify starch with respective specific characteristics, which expands the potential application of these irradiations in the starch industry.

Investigation of the mixing ratio of quince seed gum, potato starch and gellan gum on the properties of the resulting film by Mixture Design

In this study, the impact of three different biopolymers, namely, quince seed gum, potato starch and gellan gum, at levels of zero to three, on optimizing the biodegradable film was investigated. In order to prepare the mixed edible film, the textural properties of the films, water vapor permeability, water-solubility, transparency, thickness, color parameters, acid solubility and microstructure of the made films were investigated. Numerical optimization of method variables was performed based on the maximum Young's modulus and minimum solubility in water, minimum solubility in acid and minimum water vapor permeability by mixed design, using the Design-Expert software. The results showed that the increase of the quince seed gum directly affected the Young's modulus, tensile strength, elongation to break, solubility in acid, and a* and b* values. However, the rise of the potato starch and gellan gum levels increased the thickness, solubility in water, water vapor permeability, transparency, L* value and Young's modulus, tensile strength, elongation to break, solubility in acid and a* and b* values. The optimal conditions for the production of the biodegradable edible film were selected at the levels of 1.623 %, 1.637 % and 0 % for quince seed gum, potato starch and gellan gum, respectively. The results of scanning electron microscopy showed that the film had more uniformity, coherence and smoothness, as compared to other films studied. The results of this study, thus, showed that there was no statistically significant difference between the predicted and laboratory results (p < 0.05), indicating the good fit of the model designed for producing a quince seed gum/potato starch/gellan gum composite film.

The effect rules of MgCl2 and NaCl on the properties of potato starch: The inflection point phenomenon

The effects of MgCl₂ and NaCl concentrations on potato starch were analysed. With an increase in MgCl₂ and NaCl concentrations from 0 to 4 mol/L, the gelatinisation properties, crystalline properties, and sedimentation rate of potato starch all showed a trend of rising first and then falling (or falling first and then rising). The inflection points of the effect trends were observed at 0.5 mol/L. This inflection point phenomenon was further analysed. At higher salt concentrations, starch granules were found to absorb external ions. These ions enhance the hydration of starch molecules and promote starch gelatinisation. When NaCl and MgCl₂ concentrations were increased from 0 to 4 mol/L, the starch hydration strength increased 52.09 and 65.41 times, respectively. At lower salt concentrations, the ions that naturally exist in starch granules seep out of the granules. The exudation of these ions may cause a certain degree of damage to the native structure of starch granules.

Integrated design of micro-fibrous food with multi-materials fabricated by uniaxial 3D printing

Owing to the interest in sustainable foods, a new approach known as 3D food printing is being employed to make fibrous foods for meat and fish substitutes. In this study, we developed a filament structure with a multi-material ink comprising fish surimi-based ink (SI) and plant-based ink (PI), using single-nozzle printing and steaming. PI and an SI + PI mix collapsed after printing owing to their low shear modulus, although both PI and SI showed gel-like rheological behaviors. However, unlike the control, the objects printed with two and four columns per filament remained stable and fiberized after steaming. Each SI and PI sample gelatinized irreversibly at approximately 50 °C. The different rheological values of these inks after cooling resulted in relatively strong (PI) and weak (SI) fibers, which constructed a filament matrix. A cutting test demonstrated that the transverse strength of the fibrous structure of the printed objects was higher than the longitudinal strength, in contrast to that of the control. The degree of texturization increased with the fiber thickness based on the column number or nozzle size. Thus, we successfully designed a fibrous system using printing and post-processing and substantially broadened the application opportunities for creating fibril matrices for sustainable food analogs.

Relationship among gelatinization, retrogradation behavior, and impedance characteristics of potato starch

In this study, the physicochemical properties of potato starch from different varieties were investigated. Furthermore, the relationships among gelatinization, retrogradation behavior, and impedance characteristics of potato starch gels were evaluated by texture analysis, low-field nuclear magnetic resonance spectroscopy, and electrical impedance spectroscopy. The results indicated amylose content was positively correlated with setback viscosity, and negatively correlated with T_o and ΔH. In addition, impedance values of potato starch gels differed in a frequency-dependent manner. Notably, higher frequencies resulted in low diffusion of ions in prepared gels, which combined with the concentration of mobile ions in free water, led to a gradual decrease in impedance module. Compared with phase values, impedance module showed high correlation with gelatinization parameters (T_o, T_p, and T_c) and viscosity parameters (peak temperature and setback viscosity), more notably at frequencies below 100 Hz. In this context, the electric current flowed through mobile ions that interacted with bound water attached to the starch molecules at lower voltage frequencies, and were repressed by the formation of an ordered and compact gel network during retrogradation. Collectively, these results indicate that impedance spectroscopy can be potentially used as an efficient and reliable method to predict gelatinization and retrogradation behavior of potato starch.

Properties of potato starch as influenced by microwave, ultrasonication, alcoholic-alkali and pre-gelatinization treatments

The present study was framed to develop modified potato starch by various physical (microwave treatment, ultrasonication, pre-gelatinization) and chemical (alcohol-alkali) methods. Both native and modified starches were characterized on the basis of physicochemical, functional, and morphological attributes. Compared to native potato starch, modified starches exhibited improved water absorption capacity and water solubility index. The particle size of the starches was found to be in the range of 10.01-10.36 μm with negative zeta potential values. FTIR results revealed that modification in the peaks is attributed to the change in the structural configuration and re-organization of the microstructure between molecules of the starch during the treatments. The results of X-ray diffraction suggested that the typical peaks varied to a little extent with modifications and relative crystallinity was decreased for all treated starches. SEM Micrographs revealed the complete structural changes and irregularities in pre-gelatinized and chemically modified starches, whereas other modification methods maintained the structural integrity of starch granules. An increase in pasting temperature of modified starches represented a higher resistance to swelling and rupture, whereas rheologically, starches exhibited non-newtonian behavior with the shear-thinning property. Thus, the characteristics of modified starches will assist in the selection of potato starch for better applications in the food industry.

Starch biocomposites based on cellulose microfibers and nanocrystals extracted from alfa fibers (Stipa tenacissima)

Cellulose-based biopolymers have emerged as one of the most promising components to produce sustainable composites as a potential substitutes to fossil-based materials. Herein, the aim of this study is to investigate the reinforcing effect of cellulose microfibers (CMFs) and cellulose nanocrystals (CNCs), extracted from alfa fibers (Stipa tenacissima), on the properties of starch biopolymer extracted from potato. The as-extracted CMFs (D = 5.94 ± 0.96 μm), CNCs (D = 14.29 ± 2.53 nm) and starch were firstly characterized in terms of their physicochemical properties. Afterwards, CMFs and CNCs were separately dispersed in starch at different concentrations, and their reinforcing effects as well as the chemical, thermal, transparency and mechanical properties of the resulted starch-based films were evaluated. Thus, CMFs and CNCs incorporation into starch resulted in a minor impact on the films thermal stability, while a considerable impact on the transparency property was observed. In terms of mechanical properties, the addition of up to 20 wt% CMFs reduced the film's elongation but drastically increased its stiffness by 300 %. On the other hand, in the case of CNCs, a loading of 10 wt% was found to be the most effective in increasing film stiffness (by 57 %), while increasing the loading up to 20 wt% CNCs enhanced the film's ductility (strain-to-failure) by 52 %. This study showed that introduction of cellulosic fibers having different sizes into starch can produce biocomposite materials with a wide range of properties for food packaging application.

Potato starch films by incorporating tea polyphenol and MgO nanoparticles with enhanced physical, functional and preserved properties

Due to the massive environmental pollution caused by synthetic plastic packaging accumulation and contemporary necessities of food packaging materials, the biodegradable and multifunctional bionanocomposite films based on potato starch (PS) incorporating tea polyphenol (TP) and MgO nanoparticles (MgO-NPs) were successfully fabricated by the solution casting method, and their physical and functional properties and application in fruits preservation were systematically investigated. Incorporation of TP and MgO-NPs improved the films' tensile strength, UV light-blocking, hydrophobicity and thermal stability, and decreased their moisture content (from 14.02 % to 11.21 %), water solubility (from 19.57 % to 16.56 %), and water vapor permeability (from 17.32 to 9.07 × 10^-11 g∙m^-1∙s^-1∙Pa^-1). Moreover, the PS/TP/MgO-NPs films exhibited strong antioxidant activity, and remarkable antibacterial activity against Escherichia coli and Staphylococcus aureus with the diameter of inhibition zone of 25.60 mm and 27.50 mm, respectively. SEM, ATR-FTIR and XRD analyses indicated the TP and MgO-NPs were dispersed homogeneously in the PS matrix, and identified the molecular interactions of hydrogen bond, hydrophobic interaction and electrostatic attraction. Biodegradability assessment showed that all the films were rapidly decomposed within ~20 days under simulated environmental conditions. Compared to control, the PS/TP/MgO-NPs film-forming solution coatings were capable of maintaining fruit quality by reducing the change in weight loss, firmness and total soluble solids. Overall, these results suggested that the multifunctional bionanocomposite films could be a potential approach for developing sustainable active food packaging.

Degradable and stretchable bio-based strain sensor for human motion detection

In recent years, flexible strain sensors have attracted considerable attention for the great application potential in the emerging fields of wearable devices, electronic skin and health monitoring. However, most of flexible strain sensors are nondegradable, and the produced numerous electronic wastes after uselessness will seriously threaten environment and ecology. Herein, we propose a new strategy to fabricate degradable and stretchable bio-based strain sensor using candle soot (CS) particles to construct conductive pathways and chitosan, potato starch (PS), and polyvinyl alcohol (PVA) to form stretchable matrix in the presence of Fe³⁺ ions. Owing to the formation of multiple hydrogen bonding constructed by chitosan, PS and PVA as well as coordination bonding by Fe³⁺ ions, the obtained strain sensor showed high elongation at break up to 200% and good fatigue resistance. Furthermore, the firm embedding of the CS particles into the surface of the stretchable matrix endowed the strain sensor with steady sensitivity (gauge factors of 1.49 at 0-60% strain and 2.71 at 60-100% strain), fast response (0.22 s) and good repeatability even after 1000 stretching-releasing cycles. In addition, the strain sensor was successfully applied to detect various human motions including finger and wrist bending, swallowing and pronunciation. Interestingly, after connecting to an Arduino microcontroller circuit with a Bluetooth module, the strain sensor was able to wirelessly detect real-time movements of index finger joints. Different from most previously reported sensors, the prepared strain sensor in this work was completely degraded in 2 wt% CH₃COOH solution at 90 °C only within 10 min, thus effectively avoiding the production of electrical waste after the updating and upgrading of the sensors. The findings conceivably stand out as a new methodology to prepare environmental-friendly sensors in the field of flexible electronics, which is very beneficial for the sustainable development of environment and society.

Exploration of the process and mechanism of magnesium chloride induced starch gelatinization

As a new starch gelatinization method, salt induced gelatinization can not only reduce energy consumption but also impart special physicochemical properties to starch gel. In this study, the process and mechanism of MgCl₂ induced starch gelatinization were explored. The results showed that, potato starch could be gelatinized after a treatment of 4 mol/L MgCl₂ for 3 h. The gelatinization started with the slight damage of outer shells, then the internal molecules leached out through the cracks or holes to form gel, finally the outer shells disintegrated. During the gelatinization process, the viscosity and granule size gradually increased after 0.5 h, while the original crystallinity disappeared rapidly in 0.5 h. Besides, MgCl₂ significantly increased the electrostatic interaction, then made starch molecules closer to each other and become denser, which may have close relationship with the appearance of the cracks and the disappearance of crystallization. Moreover, MgCl₂ enhanced the hydration and increased the binding free energy of starch molecules, then promoted starch gelatinization and accelerated the destruction of starch structure, which may be the critical factors of the starch gelatinization induced by MgCl₂. The results will provide reference for the research and application of salt induced gelatinization.

Study of the water sorption and barrier performances of potato starch nano-biocomposites based on halloysite nanotubes

The barrier performances, in terms of water vapor sorption properties, gas and water barrier performances were analyzed on different starch-based nano-biocomposites. These multiphase systems were elaborated by melt blending starch and halloysite nanotubes at different contents with different plasticizers (glycerol, sorbitol and a mix of both polyols). The influence of the composition was investigated onto the structure, morphology, water sorption and barrier performances. As recently reported, halloysite nanoclay is a promising clay to enhance the properties of plasticized starch matrix. The barrier performances of nanofilled starch-based films were examined through gas and water permeabilities, diffusivity and water affinity. Glycerol-plasticized starch films give fine and more homogeneous nanofiller dispersion with good interfacial interactions, compared to sorbitol ones (alone or mixed), due to stronger and more stable hydrogen bonds. Tortuosity effects linked to the halloysite nanotubes were evidenced by gas transfer analysis, and exacerbated by the good interactions at interfaces and the resulting good filler dispersion. The influence of morphology and interfacial interactions towards water affinity was highlighted by moisture barrier properties. This was a key factor on the reduction of water diffusion and uptake with nanoclay content. A preferential water transfer was observed as a function of a plasticizer type in relation with the phenomenon of water plasticization in the nanocomposite systems.

Potato starch altered the rheological, printing, and melting properties of 3D-printable fat analogs based on inulin emulsion-filled gels

Plant-based oil inks that imitate the texture and melting behavior of traditional animal fats using 3D printing have been developed. The influence of the incorporation of potato starch and the type of oil on rheology and meltability was investigated. The results showed that the dynamic modulus and hardness of fat analogs increased, whereas fat analog meltability decreased with an increase in potato starch content. Coconut oil and soybean oil-containing fat analogs incorporated with proper potato starch levels exhibited good printability and similar meltability to commercial beef and pork fats. The addition of potato starch suppressed fat analog meltability as it disrupted the inulin matrix. Fat analogs containing coconut oil could be texturized at temperatures lower than those required for their soybean oil counterparts. The fat analogs were solid at room temperature, demonstrated good printability, and imitated the melting behavior of fat contained in real meat throughout the cooking process.

Rheological behaviors and physicochemical changes of doughs reconstituted from potato starch with different sizes and gluten

The effects of different sizes of potato starch on the rheological and physiochemical properties of model doughs were investigated. Compared with those of model dough prepared from original starch, the strengths of model doughs prepared from fractionated starch were higher, which indicates that fractionated starch can positively influence the properties of doughs. Additionally, the model dough prepared using large size starch granules had higher storage modulus (G'), loss modulus (G''), and composite modulus (|G*|) values compared to those of other types of dough; it also had the highest elasticity, viscosity, and strength. This might be related to its high amylose content (20.28 ± 0.69%) and high 1045 cm^-1/1022 cm^-1 ratio (1.27 ± 0.17). The model dough (S) prepared from starch with small sizes had the highest contents of disulfide bonds (2.91 μmolg^-1), β-turn (33.92 ± 1.17%), and β-sheet (22.57 ± 0.54%); and it also had better network structure and dough stability. Thus, the stability of the S model dough was affected by phosphorus (1194.57 ± 25.32 ppm) and amylopectin (84.19 ± 1.88%) content, and, moreover, by the competition for water. Stability and network structure of dough are relative to the size distribution of starch granules. Finally, a schematic model showing the mechanism of the influence of phosphorus, sulfhydryl, and disulfide bonds in fractionated starch on the rheological properties of dough was developed.

Potato starch modified by Streptococcus thermophilus GtfB enzyme has low viscoelastic and slowly digestible properties

Potato starch with high viscosity and digestibility cannot be added into some foods. To address this issue, a novel starch-acting enzyme 4,6-α-glucosyltransferase from Streptococcus thermophilus (StGtfB) was used. StGtfB decreased the iodine affinity and the molecular weight, but increased the degree of branching of starch at a mode quite different from glycogen 1,4-α-glucan branching enzyme (GBE). StGtfB at 5 U/g substrate mainly introduced DP 1-7 into amylose (AMY) or DP 1-12 branches into amylopectin (AMP), and increased the ratio of short- to long-branches from 0.32 to 2.22 or from 0.41 to 2.50. The DP 3 branch chain was the most abundant in both StGtfB-modified AMY and StGtfB-modified AMP. The DP < 6 branch chain contents in StGtfB-modified AMY were 42.68%, much higher than those of GBE-modified AMY. StGtfB significantly decreased viscoelasticity but still kept pseudoplasticity of starch. The modifications also slowed down the glucose generation rate of products at the mammalian mucosal α-glucosidase level. The slowly digestible fraction in potato starch increased from 34.29% to 53.22% using StGtfB of 5 U/g starch. This low viscoelastic and slowly digestible potato starch had great potential with respect to low and stable postprandial blood glucose.

Expression and characterization of 1,4-α-glucan branching enzyme from Microvirga sp. MC18 and its application in the preparation of slowly digestible starch

Nutraceuticals containing modified starch with increased content of slowly-digestible starch (SDS) may reduce the prevalence of obesity, diabetes and cardiovascular diseases due to its slow digestion rate. Enzymatic methods for the preparation of modified starch have attracted increasing attention because of their low environmental impact, safety and specificity. In this study, the efficient glucan branching enzyme McGBE from Microvirga sp. MC18 was identified, and its relevant properties as well as its potential for industrial starch modification were evaluated. The purified McGBE exhibited the highest specificity for potato starch, with a maximal specific activity of 791.21 U/mg. A time-dependent increase in the content of α-1,6 linkages from 3.0 to 6.0% was observed in McGBE-modified potato starch. The proportion of shorter chains (degree of polymerization, DP < 13) increased from 29.2 to 63.29% after McGBE treatment, accompanied by a reduction of the medium length chains (DP 13-24) from 52.30 to 35.99% and longer chains (DP > 25) from 18.51 to 0.72%. The reduction of the storage modulus (G') and retrogradation enthalpy (ΔHr) of potato starch with increasing treatment time demonstrated that McGBE could inhibit the short- and long-term retrogradation of starch. Under the optimal conditions, the SDS content of McGBE-modified potato starch increased by 65.8% compared to native potato starch. These results suggest that McGBE has great application potential for the preparation of modified starch with higher SDS content that is resistant to retrogradation.

The relationship between amylopectin fine structure and the physicochemical properties of starch during potato growth

The aim of this study was to explore the relationship between the structural and functional properties of starch isolated from Atlantic potatoes at different stages of growth without the effect of varieties and growth environment. The molecular size and chain-length distribution of amylopectin significantly varied with growth. The M_w and M_n of amylopectin ranged from 2.976 × 10⁷ to 4.512 × 10⁷ g/mol and 1.275 × 10⁷ to 2.295 × 10⁷ g/mol, respectively, suggested that the polydispersity varied with growth. The average chain length of amylopectin during potato growth showed small but significant changes and ranged from DP 23.59 to 24.73. Overall, A_fp chains, A_crystal chains, and B1 chains increased with growth, and B2 and B3 chains decreased with growth. There was wide variation in starch pasting, gelatinization, retrogradation, in vitro starch digestibility, swelling power, solubility, and gel stability properties. Specifically, potato starch harvested at the earliest time had the highest resistant starch content. The variation trend of swelling power and solubility was similar, reached highest value at 42 days, were 20.38 g/g and 8.83%, respectively. Correlation analysis revealed that the physicochemical properties were significantly affected by amylopectin fine structure. The results of this study enhance our understanding of the structure-function relationship of potato starch.

Anaphylaxis due to potato starch (possibly caused by percutaneous sensitization)

An 8-year-old boy with poor control of atopic dermatitis could eat potato products such as French fries without restrictions until 21 months of age. However, he developed generalized urticaria after eating potato products at the same age. Therefore, potatoes were excluded from his diet; nevertheless, he continued to consume a very small amount of potato starch but was without symptoms until the age of 8 years. At this age, he developed anaphylaxis after consuming potato starch and required administration of intramuscular epinephrine. He tested positive for potato-specific immunoglobulin E, skin prick test, and basophil activation test. He developed severe eczema with dry skin and erosion. We later discovered that potato starch had been used for play clay at his nursery school. Although he discontinued using potato starch play clay, it remained present in his surroundings for 6 years. His potato allergy may have developed and continued to worsen as a result of making indirect contact with surfaces that had previously been exposed to the allergen. Two-dimensional Western blot analysis on potato starch revealed the presence of proteins binding to the immunoglobulin E of the patient. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis findings showed that 5 of the 6 protein bands had a similar molecular weight as that of potato proteins. Thus far, there are no reports of anaphylaxis due to potato starch. Children with atopic dermatitis or damaged skin may have sensitivity to potato starch and could develop anaphylaxis as noted in this case.

Planetary ball-mill as a versatile tool to controlled potato starch modification to broaden its industrial applications

Pure potato starch has been modified by high-energy-ball-milling as a function of energy supplied, aiming to obtain products for different possibilities of industrial application. Burgios's equation has been used to calculate the energy supplied. The effect of the milling has been followed by a characterization of the starch morphology, crystallinity, solubility, swelling, retrogradation, viscosity, apparent viscosity, functional groups, and reducing sugar concentration. The high-energy-ball-milling not only changes the physical properties but also induces the mechanolysis of potato starch, breaking the glycosidic linkages of the starch molecules. A representation of the possible mechanism of starch mechanolysis is proposed. Three stages of the transformation of potato starch through high-energy ball-milling can be identified. Each of these stages generates starch with properties that can be used in different industrial applications.

Physicochemical properties and structure of modified potato starch granules and their complex with tea polyphenols

The physicochemical, rheological properties and structure of potato starch and starch-tea polyphenols (TPs) complex modified by enzyme and alcohol was investigated in this study. Cavities on the modified starch granules and morphology change could be investigated by SEM, while significant birefringence observed in complete granules by polarizing light microscope, but disappeared in crashed starch. TPs inhibited the aggregation of amylose and retrogradation of starch-TPs complex, resulting in the decrease of gel strength, and the increase of viscosity and gelatinization stability of starch granules. Fourier transform infrared (FT-IR) spectra showed that intramolecular hydrogen bond could be formed between TPs with modified starch, and the hydrogen bond force formed by starch and TPs was stronger than that between starch molecules. X-ray diffraction (XRD) analysis revealed that three modification methods did not change the crystalline structure of starch, but new diffraction peaks appeared in the four starch-TPs complex, suggesting that the hydrogen bond was incurred by interaction between TPs and amylose to form V-type crystalline. These results demonstrated that the complex formed by TPs and native/modified potato starch could be used in food industrial applications due to the inhibition of starch retrogradation.

Enzymatic properties of an efficient glucan branching enzyme and its potential application in starch modification

Glucan branching enzymes (GBEs, EC 2.4.1.18) catalyze the formation of α-1,6-linked branch in starch, which is important for the starch modification with prospective properties. In this study, the aqGBE gene encoding an efficient glucan branching enzyme was cloned from Aquabacterium sp. strain A7-Y and successfully expressed in Escherichia coli BL21 (DE3). The specific activity of the purified recombinant enzyme rAqGBE was 2850 U/mg with potato starch as the optimal substrate, and the K_m and V_max values of rAqGBE were 1.18 mg/mL and 588.2 μmol/min/mg, respectively. Enzymological characterization showed that rAqGBE exhibits its optimal activity under the condition of 40 °C and pH 7.0, respectively, which is independent of calcium ions. Otherwise, rAqGBE-treated potato starch showed different chain length distribution compared with control, the numbers of short chains (degree of polymerization, DP < 7) and long chains (DP > 25) increased from 4.5% to 9.6% and 6.1%-15.7% after enzymatic treatment, respectively. In starch anti-ageing assay, with minimum usage of 0.8 mg rAqGBE per g starch, the rAqGBE-treated potato starch exhibited reduced retrogradation properties. Our results indicate that the branching enzyme AqGBE may therefore be a promising tool for the enzymatic modification of starch.

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.

Effects of pullulanase debranching on the properties of potato starch-lauric acid complex and potato starch-based film

The effects of different debranching time on the properties of potato starch and its films were evaluated. Potato starch granules were debranched with pullulanase for 0, 0.5, 1.0, 1.5 or 2.0 h. The effects of pullulanase debranching treatment on the chain-length distributions of amylopectin were analysed by high performance anion exchange chromatography (HPAEC), which proved that the shorter debranching treatment generated more linear chains with favourable lengths to facilitate the formation of potato starch-lauric acid complexes. The debranched starch-lipid complexes showed higher lauric acid content than that of the untreated sample. X-ray diffraction showed that the diffraction intensity of the debranched sample was stronger than that of the undebranched sample, and when the debranching time was >1.5 h, the diffraction intensity and relative crystallinity of the complexes decreased. The sample exhibited a high melting enthalpy (ΔH) under the pullulanase debranching treatment for 1.5 h. Scanning electron microscope data indicated that the surface of the composite film was flatter after the debranching treatment and that the films exhibited the lowest water vapour permeability and highest tensile strength after the treatment time for 1.5 h.

Preparation of chitosan/curcumin nanoparticles based zein and potato starch composite films for Schizothorax prenati fillet preservation

The aim of this study was to develop a zein/potato starch (PS) film based on chitosan nanoparticles incorporated with curcumin (CCN). The CCN film was characterized for encapsulation efficiency, particle size, zeta potential, polydispersity index (PDI), relative release, and DPPH radical scavenging test. Our results showed that the CCN encapsulated effectively curcumin (CUR) (84.8% ± 1.1%) and presented with high oxidation resistance and relative release efficiency. The CCN/zein/PS composite films were round, smooth, and compact. We measured and compared the mechanical properties, oxygen permeability (OP), water vapor permeability (WVP), relative release efficiency, and DPPH radical scavenging properties of the composite films of different mass ratios. We observed that the composite film had good mechanical and barrier properties. Further, we evaluated the preservative efficacy of the composite film on Schizothorax prenati fillets by measuring pH, total volatile basic nitrogen (TVB-N), thiobarbituric acid-reactive substances (TBARS), hardness, microbial counts, organoleptic characteristics, and other fillet quality parameters. The CCN/zein/PS composite film delayed physicochemical changes in the Schizothorax prenati fillets and prolonged their shelf life by up to 15 days. In conclusion, our work shows that CCN/zein/PS composite film holds promise as a potential bioactive packaging material for Schizothorax prenati fillets.

Physicochemical properties of potato starch fermented by amylolytic Lactobacillus plantarum

This study investigated the effect of fermentation by Lactobacillus plantarum CGMCC 14177 strain on physicochemical properties and morphological characteristics of potato starch. The maximum total amylase and α-amylase production of L. plantarum CGMCC 14177 were 286.8 and 208.1 U/g, respectively. Fermented granules clearly exhibited pocked and dimpled surfaces. The granule properties changed to have a 1.9% increase in relative crystallinity. Overall the starch changed to have slight increases in onset and peak temperature, but resulted decreases of conclusion temperature and enthalpy. Fermentation decreased peak viscosity and breakdown value, while increased trough viscosity, final viscosity, and setback. Further analysis showed that fermentation increased the gel hardness and chewiness of the potato starch, but made little differences in the springiness, cohesiveness and resilience. Collectively, these results provide insight on how Lactobacillus strains can be used to modify the physicochemical properties of potato starch in ways that extend its use in industrial applications.

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.

Synthesis and functional properties of gelatin/CA-starch composite film: excellent food packaging material

In this work, citric acid (CA) modified starch/gelatin composite films were prepared by mixing modified starch and gelatin in different proportions (1:0, 1:1, 1:4, 4:1 and 0:1). Blending of chemically modified starch with food grade CA and gelatin as second polymers were studied as a new and novel approach for fabrication of eco-friendly composite films with excellent packaging properties. Taking considerations of improvement in functional properties of the films, a series of starch films were derived using CA-starch and gelatin using solution casting approach. Influence of CA (0.5%, 1%, 3%, 5% and 7% w/w of total starch) on functional properties (moisture content, solubility, swelling index, moisture migration rate, moisture absorption, opacity and mechanical properties) were studied. FTIR and SEM analysis were utilized to characterize the interaction between the starch chains and surface morphology of films. Findings revealed that functional properties (aqueous solubility, swelling index, and moisture barrier properties) significantly (p < 0.05) improved as CA content increased. Composite films with CA-starch/gelatin of the ratio (4:1) revealed excellent functional properties. FTIR spectra illustrated strong interaction between the starch chains in the starch films. SEM analysis showed that gelatin exhibited good compatibility in the composite films. Therefore obtained composite films possessed a homogenious, dense and compact networks. In conclusion, CA and gelatin made better starch film properties and broadened the potential applications in the food packaging.