Native Potato Research Articles

Bioactive Compounds and Sensory Quality in Chips of Native Potato Clones (Solanum tuberosum spp. andigena) Grown in the High Andean Region of PERU.

Native potatoes (Solanum tuberosum spp. andigena) have diverse pigments and are cultivated in Peru's high Andean regions; they are characterized by containing bioactive compounds that prevent various degenerative diseases. The study aimed to evaluate the physicochemical and sensory quality in chips of native potato clones grown at 3496 m altitude, for which the potatoes were cut into slices and fried in extra virgin olive oil at 180 °C for 200 s. This was determined by proximal analysis, reducing sugars, minerals, color, antioxidant capacity (AC), total phenolic compounds (TPC), and anthocyanins in fresh and chips; an instrumental characterization by FTIR and SEM and sensory tests were also performed. The native potatoes presented low moisture and reduced sugar contents; when frying, their bioactive properties improved, increasing AC, TPC, and trace elements, such as K, Mg, Ca, P, Fe, and Zn. To conclude, fresh clones have high yields in the field and are an essential source of nutrients and bioactive; the salt-free chips of clone B presented better physicochemical properties and greater sensory acceptance, closely followed by clone A. Both clones could be used as raw material by food companies that produce snacks to benefit high Andean agricultural producers.

Nanoencapsulation of Phenolic Extracts from Native Potato Clones (Solanum tuberosum spp. andigena) by Spray Drying.

Native potato clones grown in Peru contain bioactive compounds beneficial to human health. This study aimed to optimize the spray-drying nanoencapsulation of native potato phenolic extracts utilizing a central composite design and response surface methodology, obtaining the optimal treatment to an inlet temperature of 120 °C and an airflow of 141 L/h in the nano spray dryer B-90, which allowed maximizing the yield of encapsulation, antioxidant capacity (DPPH), encapsulation efficiency (EE), total phenolic compounds, and total flavonoids; on the other hand, it allowed minimizing hygroscopicity, water activity (Aw), and moisture. Instrumental characterization of the nanocapsules was also carried out, observing a gain in lightness, reddening of the color, and spherical nanoparticles of heterogeneous size (133.09-165.13 nm) with a negative ζ potential. Thermal, infrared, and morphological analyses confirmed the encapsulation of the core in the wall materials. Furthermore, an in vitro release study of phenolic compounds in an aqueous solution achieved a maximum value of 9.86 mg GAE/g after 12 h. Finally, the obtained nanocapsules could be used in the food and pharmaceutical industry.

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.

Multimetal removal in aqueous medium using a potato starch/nopal mucilage copolymer: A study of adsorption kinetics and isotherms

In reducing heavy metals from water for direct or indirect consumption, various synthetic materials have been used; there is a tendency to use natural, biodegradable, and environmentally friendly materials. The aim was to elaborate copolymers with native potato starch and cactus mucilage and evaluate water's multimetal removal capacity. The copolymer was characterized, and the kinetics and adsorption isotherms were evaluated. The copolymers presented high solubility for nopal mucilage levels of 5% w/w, with particle size in aqueous solution less than 422.83 nm, zero charge point around pH 5.5, and potential ζ between −16.72 and −29.80 mV; FTIR analysis showed the predominance of anionic groups with chelating capacity. Multimetal adsorption was from 102.20 to 151.43 mg/g, with affinity in the order Pb > As > Al > Hg > Cr, being higher at pH 6 (p-value<0.05). Kinetic data were fitted to the PSFO, PSSO, and Elovich models with R2>0.994, X2<16.098, ARE<34.038, and random residual dispersion, indicating a chemisorption process. The adsorption isotherms were adjusted to the Langmuir, Freundlich, and Redlich-Peterson models with R2>0.863, whose parameters are related to the ionic radius of the metals, with favorable adsorption and a heterogeneous surface of the copolymer. The mean adsorption energy was found between 0.05 and 0.23 kJ/mol. The use of native potato starch and cactus mucilage allows the formulation of copolymers with high multimetal adsorption potential in aqueous systems.

Evaluation of the multiplication of three native potato (Solanum sp.) varieties for the conservation of native species

Evaluation of the multiplication of three native potato (Solanum sp.) varieties for the conservation of native species

Microencapsulation of Propolis and Honey Using Mixtures of Maltodextrin/Tara Gum and Modified Native Potato Starch/Tara Gum.

Ethanolic extracts of propolis and bee honey contain substances beneficial to human health. Mixtures of wall materials were compared in spray-drying microencapsulation of ethanolic extracts of propolis and bee honey rich in bioactive compounds. Maltodextrin and tara gum were used to obtain microencapsulates A, and modified native potato starch and tara gum were used for microencapsulates B. High values of phenolic compounds, flavonoids, and antioxidant capacity were obtained in microcapsules A and B, and the results obtained in terms of encapsulation efficiency, yield, hygroscopicity, solubility, moisture, Aw, bulk density, and color were typical of the spray-drying process. On the other hand, spherical and elliptical microparticles of sizes between 7.83 and 53.7 µm with light and medium stability were observed. Thermogravimetric properties were similar in both microencapsulates; total organic carbon, SEM-EDS, and FTIR analyses corroborated the encapsulation. X-ray diffractogram exhibited amorphous structures, and the release kinetics of phenolic compounds presented high values from 8.13 to 12.58 mg GAE/g between 7 and 13 h. Finally, modified potato starch is a better encapsulant than maltodextrin because it has better core protection and controlled release of the encapsulated bioactive compounds.

Клейстеризація картопляного крохмалю способом in vitro за надмірного вмісту води. 1. Кінетика процесу в ізотермічних умовах

The wide use of starches in the food industry determines their comprehensive study over many years. One of the key problems that need to be solved for the improvement of food technologies in which starch is used is the definition of the basic laws of the kinetics of the gelatinization process of starches. The purpose of this work was to determine the kinetic parameters of the gelatinization process of native potato starch with excessive water content in the reaction mixture (the modulus is 10 g/l) and to select the appropriate kinetic model. It was found that the kinetics of the gelatinization process of native potato starch is described by the Kruger-Ziegler equation. It is shown that the dependence of the rate constant of the gelatinization process on the temperature in Arrhenius coordinates has the shape of a convex curve. It can be assumed that at a temperature below 70 °С the process proceeds in the kinetic region with the limiting stage of the chemical reaction at the interface of the phases and when the temperature increases then transition to the diffusion region occurs. It is assumed that the essence of the specified chemical reaction means the formation or destruction of hydrogen bonds during the interaction between water molecules and amylose. The values of the imaginary activation energy of the gelatinization process calculated from experimental data are 191.3 kJ/mol in the temperature range of 60—70 °С and 22.2 kJ/mol in the temperature range of 80—90 °С. The high values of the activation energy at a temperature below 70 °С can be explained by the energy spent on breaking hydrogen bonds between the OH groups of amylose macromolecules. It is proposed to intensify the process of gelatinization of starch by increasing the temperature and using a catalyst at temperatures below 70 °С. If the process is carried out in the area of high temperatures, then its intensification can be achieved by grinding starch granules and increasing the mixing speed of the starch suspension.

Biochemical characteristics and potential application of a thermostable starch branching enzyme from Bacillus licheniformis

Slowly digestible starch (SDS) has attracted increasing attention for its function of preventing metabolic diseases. Based on transglycosylation, starch branching enzymes (1,4-α-glucan branching enzymes, GBEs, EC 2.4.1.18) can be used to regulate the digestibility of starch. In this study, a GBE gene from Bacillus licheniformis (bl-GBE) was cloned, expressed, purified, and characterized. Sequence analysis and structural modeling showed that bl-GBE belong to the glycoside hydrolase 13 (GH13) family, with which its active site residues were conserved. The bl-GBE was highly active at 80 °C and a pH range of 7.5–9.0, and retained 90% of enzyme activity at 70 °C for 16 h. bl-GBE also showed high substrate specificity (80.88 U/mg) on potato starch. The stability and the changes of the secondary structure of bl-GBE at different temperature were determined by circular dichroism (CD) spectroscopy. The CD data showed a loss of 20% of the enzyme activity at high temperatures (80 °C), due to the decreased content of the α -helix in the secondary structure. Furthermore, potato starch treated with bl-GBE (300 U/g starch) showed remarkable increase in stability, solubility, and significant reduction viscosity. Meanwhile, the slowly digestible starch content of bl-GBE modified potato starch increased by 53.03% compared with native potato starch. Our results demonstrated the potential applications of thermophilic bl-GBE in food industries.

PHASE DIAGRAMS OF HYDROLYSATES WITH DIFFERENT DEGREE OF DEPOLYMERIZATION OBTAINED BASED ON CHEMICALLY MODIFIED STARCHES

Background. One of the best ways to present the relationship between phase changes and the stability of food products related to water content and temperature change is a phase diagram. The aim of the pre-sented research was to develop phase diagrams for maltodextrins obtained from native potato starch and acetylated potato starch (E14120) and distarch phosphate (E1412). For this purpose, glass transition curves and freezing curves were determined using the DSC (differential scanning calorimetry) method. As part of the research, an attempt was also made to assess the impact of modification of the original material and the degree of saccharification on the parameters that determine storage stability. Samples with different water activity were obtained by placing dried maltodextrins in an environment with different humidity. The glass transition temperature and freezing temperature were determined using DSC. The results were described using the Gordon and Taylor equation and the Chen equation, and phase diagrams were prepared. Results and conclusions. The glass transition temperature of anhydrous maltodextrins (Tgs) varied in the range of 131.4 ÷ 172.5 ºC depending on the type of modification of base starch and DE. The glass transition temperature (Tg) of all samples decreased with increasing water activity. The obtained values of the k constant of the Gordon-Taylor model ranged from 4.81 to 5.70, and the parameters of the Chen model varied from -0.334 to -0.123 (parameter B) and from 0.074 to 0.117 (parameter E). The values of unfreezable water Xw' (from 0.218 to 0.218 kg of water/kg of sample) and temperature Tm' (from -18.6 to -14.9 °C) and Tg' (from -42.1 to -22.4 °C) determined using a phase diagram for individual maltodextrin samples depended on DE and the type of modification of base starches. The research performed allows us to conclude that native and modified starch hydrolysates were characterized by different thermal proper-ties, which provides wide possibilities of their use in industrial processes.

Preparation and characterization of type 3 resistant starch by ultrasound-assisted autoclave gelatinization and its effect on steamed bread quality.

In this study, we aimed to establish an innovative and efficient preparation method of potato resistant starch (PRS). To achieve this, we prepared type 3 resistant starch (RS3) from native potato starch (PS) using an ultrasonic method combined with autoclave gelatinization and optimized by the response surface method to study the structure and properties of potato RS3 (PRS3) and its effect on the quality of steamed bread. Under optimal treatment conditions, the PRS3 content increased from 7.5% to 15.9%. Compared with PS, the B-type crystal structure of PRS3 was destroyed, and the content of hydroxyl groups was increased, but no new chemical groups were introduced. PRS3 had a rougher surface and a lower crystallinity, gelatinization temperature, viscosity, setback value, and breakdown value. The low content (5%) of PRS3 had a stable viscosity and was easily degraded by bacteria, which can improve the quality of steamed bread to a certain extent. When the PRS3 content was over 10%, it competed with the gluten protein to absorb water, which reduced the contents of β-turn and α-helix in the dough, increased the contents of β-fold, and weakened the structure of the gluten network. It also decreased the specific volume and elasticity of the steamed bread and increased the spreading rate, hardness, and chewiness. Steamed bread prepared with a flour mixture containing 5% PRS3 was similar to the presidential acceptance of control flour. In this study, a new sustainable and efficient PRS3 preparation method was established, which has certain guiding significance for the processing of Functional steamed bread with high-resistant starch.

Resistance Evaluation for Native Potato Accessions against Late Blight Disease and Potato Cyst Nematodes by Molecular Markers and Phenotypic Screening in India.

The potato originated in southern Peru and north-western Bolivia (South America). However, native accessions have also been cultivated in India for many years. Late blight, caused by the fungus Phytophthora infestans, is the most devastating potato disease, while potato cyst nematode (Globodera spp.) (PCN) is another economically significant quarantine-requiring pest in India. In this study, we have generated a new Indian native collection of 94 potato accessions collected from different parts India. These accessions were screened against late blight and potato cyst nematode resistance by using gene-based molecular markers and phenotypic screening methods. Marker assisted selection using R1 gene-specific marker CosA210 revealed a late blight resistance gene in 11 accessions. PCN resistance bands were found in 3 accessions with marker TG689141, 5 accessions with marker 57R452, and 1 accession having Gro1-4-1602 marker for G. rostochiensis (Ro1,4), while 64 accessions amplified marker HC276 indicating G. pallida (Pa2,3) resistance gene (GpaVvrn QTL). On the other hand, phenotypic screening against late blight resistance under natural epiphytic conditions (hot-spot) revealed three accessions with high resistance, while others were resistant (1 accession), moderately resistant (5 accessions), susceptible (29 accessions), and highly susceptible (56 accessions). For G. rostochiensis (golden cyst nematode) and G. pallida (white cyst nematode) resistance, accessions were grouped into highly resistant (3, 3), resistant (0, 2), moderately resistant (6, 29), susceptible (32, 30), and highly susceptible (53, 30), respectively, for the two PCN species. Collectively, we identified promising accessions with high resistance to late blight (JG-1, Kanpuria Safed, and Rangpuria), and also highly resistant to both Globodera species (Garlentic, Jeevan Jyoti, and JG-1). Our findings suggested that these accessions would be useful for late blight and PCN resistance breeding, as well as future molecular studies in potatoes.

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.

Physicochemical and Technofunctional Comparison of Starch from Varieties of Native Potato (Solanum Phureja) with Commercial Starches

Due to the high genetic variability of the potato, the starch can exhibit different properties of interest to the industry. With the present investigation, it is intended to know these differentiating characteristics in comparison with commercial sources that can be useful in different sectors. Therefore, the objective of this research was to establish a comparison between potato starches extracted from native varieties (Solanum phureja) with commercial potato and corn starches. A physicochemical analysis was carried out, for which characteristics such as amylose content, phosphorus, resistant starch (RS), slow digestibility starch (SDS), rapid digestibility starch (RDS), granule shape, granule size and crystallinity were evaluated. The technofunctional analysis included variables such as amylographic, thermogravimetric and differential scanning calorimetry analysis. The starches of the native varieties exhibited differential characteristics with respect to the commercial starches. Andina variety obtained the highest peak viscosity (8714 cP), followed by Ratona Blanca starch (6148 cP). In addition, these two varieties had the highest content of resistant starch (33.14±0.8) % and (28.9±0.7) % respectively), higher content of amylose (33.9 % and 35.5 % respectively), phosphorus (&gt;0,08 % for both varieties), high crystallinity and higher enthalpy values (&gt; 19 J/g for both varieties), which make them materials of potential use in different industries. The correlations presented between variables such as resistant starch (RS), enthalpy and crystallinity, showed possible differences at the structural level, which highlighted the differential characteristics of each starch.

Nitrostarch as a promising insensitive energetic biopolymer: Synthesis, characterization, and thermal decomposition kinetics

Natural polysaccharides have been outlined as one of the natural sources with more potential to obtain bio-energetic polymers through the chemical modification of their structure. In this work, nitrostarch, as an energetic nitrogen-rich polysaccharide, was successfully synthesized through the chemical modification of native potato starch . The synthesized energetic polymer and its precursor were extensively characterized using various analytical techniques and the obtained results confirm the functionalization process of the starch. In addition, its physicochemical features, molecular structure, morphology, and thermal behavior were determined using an electronic densimeter, elemental analysis, FTIR, SEM, TGA, and DSC . The sensitivity characteristics, the heat of combustion, and the heat of formation of the synthesized nitrostarch have been determined and its energetic performances were predicted using the EXPLO5 V6.04 software. Experimental results highlight promising features of the nitrostarch such as nitrogen content of 13 %, a density of 1.7365 g/cm 3 , and a detonation velocity of 7892 m/s in comparison to those of conventional nitrocellulose . In addition, the thermal decomposition kinetics of the nitrostarch have been deeply investigated as well using isoconversional kinetics analysis, and its Arrhenius parameters were derived for the first time. Finally, the obtained results demonstrated that this newly produced nitrogen-rich energetic material exhibits interesting energetic performance, which may further promote its application in explosives and high-performance propellants. In addition, this study will help to restore the forgotten interest concerning the employment of nitrostarch as a high-energy bio-polymer and to complete knowledge gaps and future trends for the industrial applications of this compound. • Nitrostarch was successfully prepared from native potato starch. • The properties of nitrostarch were compared to those of cellulose nitrate. • The synthesized nitrostarch revealed high nitrogen content, increased densities, good thermal stability, and outstanding insensitivity characteristics. • The thermal decomposition kinetics of nitrostarch has been deeply investigated and reported for the first time in the literature. • The calculated detonation parameters highlighted the interesting energetic performances of nitrostarch.

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.

Targeted hydrolysis of native potato protein: A novel workflow for obtaining hydrolysates with improved interfacial properties

Peptides and protein hydrolysates are promising alternatives to substitute chemical additives as functional food ingredients. In this study, we present a novel workflow for producing a potato protein hydrolysate with improved emulsifying and foaming properties using quantitative proteomics and bioinformatic prediction to facilitate targeted hydrolysis design. Based on previous studies, we selected 15 potent emulsifier peptides derived from abundant potato proteins as targets. Through in silico analysis, we determined that from a range of industrial proteases (Neutrase (Neut), Alcalase (Alc), Flavourzyme (Flav) and Trypsin (Tryp)), Tryp was found more likely to release peptides resembling the targets. After applying all proteases individually, hydrolysates were assayed for in vitro emulsifying and foaming properties. No direct correlation between degree of hydrolysis and interfacial properties was found. Tryp (E/S = 3%) produced a hydrolysate (DH = 5.4%) with high aqueous solubility and the highest (P < 0.05) emulsifying and foaming abilities, validating the hypothesis. Using LC-MS/MS, we identified >10,000 peptides in each hydrolysate. Peptide mapping revealed that random overlapping with known peptide emulsifiers is not sufficient to quantitatively describe hydrolysate functionality. However, validated release of targeted peptides by 3% Tryp appears to increase surface activity of the hydrolysate. Our data also suggest that terminal hydrophobic anchor domains may be important for high interfacial partitioning and activity. While modest yields and residual unhydrolyzed protein indicate room for process improvement, this work shows that bioinformatics-guided and data-driven targeted hydrolysis is a promising, interdisciplinary approach to facilitate process design for production of functional hydrolysates from alternative protein sources.

Chemical Modifications of Normal and Waxy Potato Starches Affect Functional Properties of Aerogels.

Aerogels are of increasing interest because of their exceptionally large surface area, porous structure, and low weight. Despite the significant increase in interest in the subject of starch-based aerogels, the number of detailed studies is rather scarce, which is especially evident in the case of chemically modified derivatives. Therefore, the study aims to evaluate the physicochemical properties of aerogels from chemically modified potato starch preparations (E 1422 and E 1450) obtained both from normal and waxy starches. Aerogels were prepared through the retrogradation of starch pastes followed by the gradual replacement of water with ethyl alcohol. The obtained preparations were characterized in terms of their bulk density, oil-binding capacity, as well as the texture and rheological properties of the formed pastes. Moreover, their usefulness was evaluated in an emulsion system employing rheological and low-field NMR methods. The obtained aerogels were characterized by a lower bulk density of 0.18-0.59 g/cm3 and 5.4-6.6 times higher oil-binding capacity compared to native potato starch. The chemical modification of starch helped to further alter the functional properties of the obtained aerogels, making them more effective oil binders, emulsifiers, and stabilizers (increasing the stability from 55 to 90%), which was especially evident for E 1450 preparation. Amylose content improved the aerogel properties, as waxy preparations were characterized by worse functional properties with the only exception of improved thickening ability. The most beneficial properties for the preparation of emulsions were observed for the aerogel obtained based on E 1450 normal potato starch.

Curcumin encapsulation in capsules and fibers of potato starch by electrospraying and electrospinning: Thermal resistance and antioxidant activity

The aim of this work was to encapsulate curcumin at different concentrations in capsules and fibers of native potato starch by electrospraying and electrospinning. The best conditions for the production of capsules and fibers were obtained by varying the polymer concentration and resting time of the polymer solution. The best conditions were used for the encapsulation of curcumin. The curcumin-loaded capsules and fibers had an average diameter of 1373 nm to 1787 nm and 108 nm to 142 nm, respectively, and had a high curcumin loading capacity with values ranging from 79.01 % to 97.09 %. Curcumin encapsulated in starch capsules and fibers showed higher thermal stability at 180 °C for 2 h compared to unencapsulated curcumin. The antioxidant activity of starch fibers containing 1 % of curcumin had the greatest ability to inhibit the ABTS radical (45 % inhibition). These materials are promising for use in food or active packaging.

Biodegradable composite material based on the starch-g-vinyl acetate copolymer

A native potato starch was modififi ed with vinyl acetate by graft polymerization in alkaline medium with pH 10 in the mode of temperature change from 70 to 80°C for 4 hours. The initiator of the process was ammonium persulfate (NH4)2S2O8. The conversion of vinyl acetate was 91,5%. The chemical structure of graft copolymer (Starch:Vinyl acetate) was confifi rmed by IR-spectroscopy. Composite materials of modififi ed starch and triethyl citrate with tensile strength of 24 MPa were obtained. Under natural environmental conditions, materials undergo biodegradation of 96% in 28 days.

Effects of hot air and radiofrequency multi-stage drying for native potato flour processing: Functional and chemical characteristics

Native potato flour is one of the most promising food sources or additives to meet the increasing need for healthy food. Multi-stage drying is one of the most promising methods for potato drying, but the chemical and functional properties need to be evaluated. In this work, the soluble peptide, digestibility, enzyme activity, flavonoid, and odorants with multi-stage drying methods were studied. Results showed that high-temperature first stage (HTFs) treatment enhanced the slowly digestible starch content and Maillard reaction, but the highest effective concentration for 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radicals scavenging ratio at 50% (77.62 mg/mL), and 6.995 mg/mL of soluble peptide could be found for the 90 + 60 °C hot air dried sample. This indicated that longstanding decelerate drying stage treatment has obvious damage effects on antioxidant activity and proteins. The HTFs treatment has positive effects to enhance the drying rate and quality of native potato flour, but the second stage needs to be minimized. Moreover, radiofrequency assisted method might be a better solution.