Changes in physicochemical properties of corn starch upon modifications by atmospheric pressure plasma jet

Accepted Manuscript Changes in physicochemical properties of corn starch upon modifications by atmospheric pressure plasma jet Tsung-Yen Wu, Chih-Ren Chang, Tsai-Ju Chang, Yu-Ju Chang, Ying Liew, Chi-Fai Chau PII: DOI: Reference:

S0308-8146(19)30111-6 https://doi.org/10.1016/j.foodchem.2019.01.043 FOCH 24138

To appear in:

Food Chemistry

Received Date: Revised Date: Accepted Date:

1 October 2018 19 December 2018 4 January 2019

Please cite this article as: Wu, T-Y., Chang, C-R., Chang, T-J., Chang, Y-J., Liew, Y., Chau, C-F., Changes in physicochemical properties of corn starch upon modifications by atmospheric pressure plasma jet, Food Chemistry (2019), doi: https://doi.org/10.1016/j.foodchem.2019.01.043

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Changes in physicochemical properties of corn starch upon

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modifications by atmospheric pressure plasma jet

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Tsung-Yen WUa, Chih-Ren CHANGb,c, Tsai-Ju CHANGb, Yu-Ju CHANGb, Ying LIEWb, and Chi-

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Fai CHAUb,*

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a

Agricultural Chemistry Division, Taiwan Agricultural Research Institute, Council of Agriculture,

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No.189, Zhongzheng Rd., Wufeng Dist., Taichung 41362, Taiwan

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b

Department of Food Science and Biotechnology, National Chung Hsing University, 145 Xingda

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Road, Taichung 40227, Taiwan c

Department of Traditional Chinese Medicine, Puli Branch of Taichung Veterans General Hospital, No.1, Rongguang Rd., Puli Township, Nantou County 545, Taiwan

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*Corresponding authors. Department of Food Science and Biotechnology, National Chung Hsing

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University, 145 Xingda Road, Taichung 40227, Taiwan

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E-mail address: [email protected] (C.-F. Chau)

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Telephone: +886-4-22852420

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Fax: +886-4-22876211

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Running title: Modifications of corn starch by employing atmospheric pressure plasma jet

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Abstract

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The influences of atmospheric pressure plasma jet on different physicochemical properties of

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corn starch were evaluated after treated with the plasma jet (30 min) at different strengths (400W-

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800W). Our results demonstrated that residual aging effects of plasma on starch could be eliminated

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by washing the treated samples with distilled water at a ratio of 1:30, w/v.

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treatments, significant (p < 0.05) reductions in pasting properties including peak viscosity, final

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viscosity, and setback of starch samples (up to -87.1%, -92.0%, and -93.3%, respectively) were

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observed with increasing plasma intensity.

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paste clarity of starch sample.

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etching resulted in some physical changes on starch granules.

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physicochemical properties of corn starch by employing the plasma jet treatment might be useful in

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food applications requiring starch ingredients of low viscosity and high paste clarity.

After plasma and washing

Apparently, plasma jet could increase the solubility and

Surface morphological characterization illustrated that plasma Modifications in these

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Keywords: corn starch, atmospheric pressure plasma jet, physicochemical property, starch

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modification

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1. Introduction Plasma is known as the fourth state of matter, which can be divided into high temperature and

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low temperature plasma.

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Atmospheric pressure non-thermal plasma can be generated at room temperature (290-300 K) without

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any quenching.

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applicability on some thermosensitive compounds, lower cost, and an increase in treatment efficiency

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(Nehra et al., 2008; Misra et al., 2011).

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The latter is further subdivided into thermal and non-thermal plasma.

The advantages of this non-thermal plasma in food applications might include its

Starch is one of the most widely used biopolymers in various industries, such as stabilizers and

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thickeners in food, textile, paper, and pharmaceutical industry (Thirumdas et al., 2017a).

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wider applications of starches, different chemical, physical, and enzymatic modifications were

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needed to improve their physicochemical properties (Colussi et al., 2014).

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be considered as a physical approach for starch modification. It generated different types of reactive

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species which interacted with starches and induced chemical changes to develop novel starch

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functionalities (Zhu, 2017).

To explore

Plasma technology could

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Interactions between plasma and starch would modify starch molecules through several

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mechanisms, such as cross-linking, depolymerization, and plasma etching (Morent et al., 2011).

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Different reactive species generated by plasma might lead to alterations in structures or some

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physicochemical parameters (e.g. swelling, solubility, and viscosity) of starch molecules.

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effects of plasma treatment on starches depended on several factors, including apparatus types,

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treatment conditions (feed gas, power input, and exposure time), and also the type and composition

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of starch (Zhu, 2017).

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The

In view of the advantages like simple construction, easy adoption, and high handling efficiency,

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the uses of atmospheric pressure air plasma jet has been exploited in a diversity of food research.

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this study, corn starch samples were treated with gases produced by an air plasma jet at different

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strengths.

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and compared.

In

Changes in different physicochemical properties of the treated samples were evaluated Potential applications of the air plasma jet on the modifications of corn starch were 3

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also discussed.

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2. Materials and methods

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2.1. Air plasma jet treatment

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A schematic diagram of the experimental setup is shown in Figure 1.

In this study, the input

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powers for generating cold plasma were 400W, 600W, and 800W.

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contained 73% amylopectin and 27% amylose was purchased from Sigma-Aldrich, Co. (St. Louis,

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MO, USA).

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height of 476 mm) filled with plasma gases generated from air plasma jet (SAP003X, Creating Nano

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Technologies, Inc., Taiwan) and held for 30 min.

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the treated starch samples were immediately washed with distilled water at different ratios (1:15 and

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1:30, w/v) to eliminate the residual aging effects of plasma on starch.

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centrifuged at 4000×g for 5 min and then dried in an oven at 40°C for 24 h.

Corn starch (S-4126) which

This native corn starch was placed in a reaction chamber (diameter of 295 mm and

After reacted with plasma gases in the chamber,

The starch suspension was

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To determine a proper starch-to-water ratio for washing to cease the residual aging effect of

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plasma, changes in the viscosity of treated samples were analyzed at days 0, 1, and 7 according to the

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methods as described by Wu et al. (2018) with slight modifications.

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referred to the sample analysis conducted immediately after washing and drying.

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referred to the analyses of washed samples after a storage for 24 hours and 7 days, respectively.

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set of controlled observations was also performed on the starch samples without washing after the

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plasma treatment.

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2.2. Determination of pasting properties

More specifically, day 0 Day 1 and day 7 A

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Pasting properties of corn starch samples were determined by the methods described by Wu et

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al. (2018) with slight modifications, and measured with a Rapid Visco Analyser (Model RVA-Super

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3, Newport Scientific Pty Ltd., NSW, Australia), which was controlled by the Thermocline software

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(version 2.3, Newport Scientific Pty Ltd., NSW, Australia).

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mL of distilled water in a canister.

Starch sample (3 g) was mixed with 25

The mixture was equilibrated at 50°C for 1 min, heated to 95°C 4

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at a rate of 12.2°C per min.

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50°C at a rate of 11.8°C per min and maintained at 50°C for 2 min.

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viscosity during pasting), trough viscosity (minimum viscosity at 95°C), breakdown (difference

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between the peak viscosity and trough viscosity), final viscosity, setback (difference between the final

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viscosity and trough viscosity) and pasting temperature were recorded.

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expressed by centipoise (cP).

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2.3. Determination of swelling power and water soluble index

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Sample was then held at 95°C for 2.5 min, followed by a cooling to

The units of viscosity were

The swelling power and water soluble index of starch samples were determined by the methods

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described by Li and Yeh (2001) with slight modifications.

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at 95°C for 30 min with intermittent shaking.

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an iced water bath.

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supernatant was dried in an air oven at 100°C to constant weight (W1).

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The peak viscosity (maximum

Starch suspension (2%, w/v) was heated

The suspension was cooled to room temperature in

After centrifuged at 8000×g for 20 min, the precipitate was weighed (WS).

The water soluble index and

swelling power were calculated using the following equations:

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Water soluble index (%) = [W1/weight of starch sample] × 100

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Swelling power (g/g) = WS/[weight of starch sample × (100% - water soluble index%)]

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The

2.4. Determination of starch paste clarity

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Clarity of starch paste was determined according to the methods of Wongsagonsup et al. (2014).

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Starch paste solution (1%, w/v) was prepared by heating starch sample in distilled water at 95°C for

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30 min, shaken thoroughly every 5 min, followed by a cooling to room temperature.

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of light transmittance (%T) at 650 nm was determined spectrophotometrically against distilled water.

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2.5. Morphological characterization

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The percentage

Optical and polarized light micrographs of corn starch samples were determined by Nikon

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microscope (Optiphot 2-Pol, Nikon, Tokyo, Japan) equipped with a polarizer.

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micrographs were taken with a tabletop scanning electron microscope (SEM; TM-1000, Hitachi,

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Tokyo, Japan).

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sputter coated with gold powder (at 2 mbar for 3 minutes) prior to SEM observation.

Scanning electron

Samples were mounted on a specimen holder using double-sided sticky tape and

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2.6. Statistical analysis Experimental results were statistically analyzed using the SPSS statistics program (version 20.0;

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SPSS, Armonk, NY, USA).

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multiple range test to compare mean values.

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0.05.

Analysis of variance (ANOVA) was performed using Duncan’s Statistical significance difference was defined at p <

The data presented are means of three replicates.

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3. Results and discussion

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3.1. Plasma treatment

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Aging effects and its subsequent surface modification were common phenomenon in polymers

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after plasma treatment.

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polymers over the storage period were usual.

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plasma oxidation and surface adaptation.

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Hasnain, 2014; Thirumdas et al., 2017a) which involved a continuous reaction of high-energy active

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substances (residual free radicals) produced by plasma and atmospheric oxygen.

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induce the formation of reactive oxygen and nitrogen species, as well as many unstable polar

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functional groups on the polymer surface.

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would be diminished due to the alteration in interfacial properties by a mechanism called surface

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adaptation (Siow et al. 2006).

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Changes in chemical compositions and characteristics of the treated The aging effect was basically attributed to post-

Oxidation was in fact a depolymerization process (Ali &

Plasma might

However, it was interesting that these functional groups

In Figure 2, the corn starch samples were first treated by the highest output (800W) of the power

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supply.

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(day 0), RVA analyses showed that the viscosity of treated samples dropped dramatically after the

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first 24 hours (day 1) and even became null after 7 days of storage.

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in viscosity was partly attributed to the aging effects of the residual reactive species being trapped in

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the treated starch samples as well as the instability of polar functional groups.

As compared with the initial viscosity measured immediately after the plasma treatment

It was inferred that the decrease

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In this study, the treated samples were washed with distilled water at different ratios with the

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purpose to remove the residual reactive species generated by the air plasma jet since the reactive 6

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species formed during plasma treatment dissolved readily in water (Thirumdas et al., 2018).

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3 (A) illustrates that washing the samples with distilled water at a ratio of 1:15 (w/v) could slightly

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mitigate the instability and reduction of viscosity during storage.

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the samples with a relatively larger amount of distilled water (at 1:30, w/v) was more effective in

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resolving the loss in viscosity and improving the stability of the plasma-treated samples.

Figure

As shown in Figure 3 (B), washing

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On the basis of these findings, the starch samples to be used in the other experiments of this

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study would be prepared by reacting with plasma at different strengths (400W, 600W, and 800W),

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followed by washing with an optimal amount of distilled water (at 1:30, w/v) and drying for further

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uses.

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3.2. Pasting properties

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Table 1 summarizes the pasting properties of native corn starch (control) and the other starch

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samples after the plasma treatment and subsequent washing.

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final viscosity of the starch samples decreased significantly (p < 0.05) with an increase in plasma

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intensity.

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dropping from 3181 cP (native) to 2793 cP (400W).

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significant reduction (p < 0.05) of viscosity down to 1451 cP (-54.4%) and 410 cP (-87.1%),

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respectively, were observed.

Peak viscosity, trough viscosity, and

With the plasma intensity at 400W, peak viscosity decreased (p < 0.05) by -12.2%, At higher intensities (600W and 800W), a more

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After the plasma treatment at different strengths (400-800W), trough viscosity was found to

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decrease significantly (p < 0.05) from 2055 cP (native sample) to 141-1466 cP (ranging from -26.7%

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to -93.1%).

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to -92.0% for the treated samples) was also noted.

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observed.

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starch sample prepared with plasma at 800W had the lowest viscosity.

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depolymerization are competitive reactions during plasma treatment (Wongsagonsup et al., 2014).

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It was inferred that the plasma reactive species might weaken bond strengths or even break down the

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bonds of starch molecules.

A remarkable decline in final viscosity from 3459 cP (native) to 277-2489 cP (-28.0% No apparent changes in pasting temperature were

Overall, the higher the plasma intensity, the lower the viscosity.

Table 1 shows that

In fact, cross-linking and

Destabilization of starch paste or granule resulted from molecular 7

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depolymerization and granular corrosion could lead to a viscosity reduction (Zhu, 2017). In parallel to the changes in viscosity, a reducing trend in the breakdown values was observed as

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the plasma intensity increased.

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ability to resist heating and shear stress during cooking (Adebowale et al., 2005).

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starch samples with lower breakdown values, especially of those being prepared at 800W, presented

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a better ability to withstand heating and shear stress.

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Starch samples with lower breakdown values indicated their greater It implied that the

Setback signified the degree of amylose re-association and the retrogradation tendency of starch

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paste (Charles et al., 2004; Zaidul et al., 2007).

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decreased tendency towards retrogradation.

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but plunged (p < 0.05) to 1024 cP (-27.1% at 400W), 391 cP (-72.2% at 600W), and 136 cP (-93.3%

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at 800W) after the plasma treatments.

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procedures, which was plasma treatment followed by washing, contributed to an improvement in

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paste-cooling stability and reduced retrogradation of corn starch.

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In general, starch with lower setback value had a

The setback of the native sample was 1404 cP initially,

The above results demonstrated that the sample preparation

Thus, it could be concluded that plasma treatment tended to decrease corn starch paste viscosity

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and retrogradation.

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nitrogen and helium glow-plasma would reduce the viscosity, breakdown, and setback of potato

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starch during pasting process.

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due to the destruction of starch structure and facilitated leaching of amylose molecules after applying

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another type of plasma has also been reported (Thirumdas et al., 2017b).

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treatment on starch pasting properties were therefore associated with different starch variety, plasma

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types, and treatment conditions, which included feed gas, input power, and reaction time (Thirumdas

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et al., 2017a; Zhu, 2017).

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3.3. Swelling power and water soluble index

Some similar observations reported by Zhang et al. (2015) have suggested that

In contrast, an elevation in granule swelling, solubility, and viscosity

The influences of plasma

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Swelling powers and water soluble indexes of different starch samples are shown in Table 2.

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No apparent changes in swelling power were observed between the native starch (19.14 g/g) and the

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other three plasma-treated samples (19.22-19.35 g/g). 8

The water soluble indexes of treated starch

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samples at different plasma intensities (25.34-50.70%) were about 1.3- to 2.6-fold higher (p < 0.05)

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than that of the native starch (19.46%), in particular that a 800W intensity brought about the highest

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water solubility.

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species would increase the solubility (Bie et al., 2015).

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was observed on corn starch treated by corona electrical discharge plasma (Nemtanu & Minea, 2006).

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3.4. Starch paste clarity

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The molecular degradation and oxidation of starch resulted from active plasma However, an opposite trend in solubility

As shown in Table 2, the clarity value of native corn starch was 15.7%.

Corn starch samples

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that underwent plasma treatments (at 400-800W) had significantly higher clarity values (17.95-

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29.63%), which were approximately 1.14- to 1.89-fold increase against the control.

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with the trends reported by Thirumdas et al. (2017b), the results revealed that these treatments would

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improve the starch paste clarity. Depolymerization was one of the underlying causes of the increase

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in dispersion and solubility during gelatinization, and this ended up in a raise in the clarity

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(Wongsagonsup et al., 2014).

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hydroxyl groups or more hydrogen bonds to the surrounding water molecules (Nemtanu &

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Brasoveanu, 2010).

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In agreement

Improved clarity might also be attributed to an increased exposure of

Starch clarity plays a pivotal role in food industry application, especially jelly or jelly-related

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products.

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in corn starch rendered its low paste clarity.

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applications in food industry.

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could eliminate residual reactive species, and thus offer an opportunity for widening the uses of corn

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starch in food processing.

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3.5. Morphology of starch granules

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Comparing with other types of native starch, high amylose content, lipids, and proteins These characteristics of corn starch limited its

Our results suggested that washing the starch after a plasma treatment

The polarized light and SEM micrographs of native and plasma-treated corn starches are shown

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in Figure 4.

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polarized light.

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gelatinization or crystalline region destruction.

The Maltese crosses of all starch samples (treated or untreated) were clearly seen under It indicated that air plasma jet belonging to non-thermal plasma did not cause These results agreed with the findings from Zhang 9

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et al. (2015) in which potato starch underwent nitrogen glow-plasma, ending without significant

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changes in starch granule.

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As illustrated in the SEM micrographs of different corn starch samples (Figure 4), the surface

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morphology of corn starch granules had polyhedral and irregular shapes with a diameter ranging from

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4 to 20 μm.

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surface of the starch granules and no significant changes in the overall morphology were observed.

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The phenomenon of slight scratches might be generated by the high energy electron passed through

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granules during plasma treatment (Brabosa-Canovas et al., 2000).

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appearances of starch granule surfaces were affected by the plasma intensity.

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intensity, the more the surface etching.

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would worsen the surface damage on starch granules (Thirumdas et al., 2015).

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After the plasma treatments, only some slight fissures or scratches appeared on the

Figure 4 also revealed that the The higher the

In fact, it has been reported that a high plasma intensity

Formation of cavities, fissures or tiny deposits on the surface of starch granules after plasma

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treatment have also been reported by Thirumdas et al. (2017a).

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morphology changes might be subjected to various gas compositions in plasma treatment.

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plasma caused a surface corrosion while nitrogen plasma had no effect on starch granules (Zhang et

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al., 2015).

It was interesting that the surface Helium

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4. Conclusions

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In conclusion, an inference that the plasma treatment at different intensities (400-800W) initiated

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depolymerization of native corn starch, resulting in production of small molecular fragments and

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hydrophilic functional groups could be drawn from the results.

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conditions might lead to a reduction of viscosity and an increase in solubility and starch paste clarity

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of starch.

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the plasma and subsequent washing treatments might avail food applications requiring starch with

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low viscosity as well as high paste clarity and solubility.

Consequently, the aforementioned

The modifications of different physicochemical properties of corn starch by employing

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Acknowledgements

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This work was supported by the Ministry of Science and Technology of the Republic of China

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(MOST 106-2320-B-005-006-MY3) as well as the Council of Agriculture, the Republic of China

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(107AS-3.3.1-CI-C1).

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Declarations of interest

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None

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References

251

Adebowale, A. A., Sanni, L. O., & Awonorin, S. O. (2005). Effect of texture modifiers on the

252

physicochemical and sensory properties of dried fufu. Food Science and Technology

253

International, 11(5), 373-382. https://doi.org/10.1177/1082013205058531.

254

Ali, T. M., & Hasnain, A. (2014). Morphological, physicochemical, and pasting properties of

255

modified white sorghum (Sorghum bicolor) starch. International Journal of Food Properties,

256

17(3), 523-535.

257

Barbosa‐Canovas, G. V., Zhang, Q. H., Pierson, M. D., & Schaffner, D. W. (2000). High voltage arc

258

discharge.

259

3841.2000.tb00620.x.

Journal

of

food

science,

65,

80-81.

https://doi.org/10.1111/j.1750-

260

Bie, P., Pu, H., Zhang, B., Su, J., Chen, L., & Li, X. (2016). Structural characteristics and rheological

261

properties of plasma-treated starch. Innovative Food Science & Emerging Technologies, 34,

262

196-204. https://doi.org/10.1016/j.ifset.2015.11.019.

263

Charles, A. L., Chang, Y. H., Ko, W. C., Sriroth, K., & Huang, T. C. (2004). Some physical and

264

chemical properties of starch isolates of cassava genotypes. Starch‐Stärke, 56(9), 413-418.

265

https://doi.org/10.1002/star.200300226.

266

Colussi, R., Pinto, V. Z., El Halal, S. L. M., Vanier, N. L., Villanova, F. A., e Silva, R. M., ... & Dias,

267

A. R. G. (2014). Structural, morphological, and physicochemical properties of acetylated high-,

268

medium-, and low-amylose rice starches. Carbohydrate polymers, 103, 405-413.

269

https://doi.org/10.1016/j.carbpol.2013.12.070. 11

270

Li, J. Y., & Yeh, A. I. (2001). Relationships between thermal, rheological characteristics and swelling

271

power

272

https://doi.org/10.1016/S0260-8774(00)00236-3.

273 274

for

various

starches.

Journal

of

Food

Engineering,

50(3),

141-148.

Misra, N. N., Tiwari, B. K., Raghavarao, K. S. M. S., & Cullen, P. J. (2011). Nonthermal plasma inactivation of food-borne pathogens. Food Engineering Reviews, 3(3-4), 159-170.

275

Morent, R., De Geyter, N., Desmet, T., Dubruel, P., & Leys, C. (2011). Plasma surface modification

276

of biodegradable polymers: a review. Plasma processes and polymers, 8(3), 171-190.

277

https://doi.org/10.1002/ppap.201000153.

278 279

Nehra, V., Kumar, A., & Dwivedi, H. K. (2008). Atmospheric non-thermal plasma sources. International Journal of Engineering, 2(1), 53-68.

280

Nemtanu, M. R., & Minea, R. (2006, December). Functional properties of corn starch treated with

281

corona electrical discharges. In Macromolecular Symposia (Vol. 245, No. 1, pp. 525-528).

282

Weinheim: WILEY‐VCH Verlag. https://doi.org/10.1002/masy.200651375.

283 284

Nemtanu, M., & Brasoveanu, M. (2010). Functional properties of some non-conventional treated starches. In Biopolymers. InTech.

285

Siow, K. S., Britcher, L., Kumar, S., & Griesser, H. J. (2006). Plasma methods for the generation of

286

chemically reactive surfaces for biomolecule immobilization and cell colonization‐ a review.

287

Plasma processes and polymers, 3(6‐7), 392-418. https://doi.org/10.1002/ppap.200600021.

288

Thirumdas, R., Deshmukh, R. R., & Annapure, U. S. (2015). Effect of low temperature plasma

289

processing on physicochemical properties and cooking quality of basmati rice. Innovative Food

290

Science & Emerging Technologies, 31, 83-90. https://doi.org/10.1016/j.ifset.2015.08.003.

291

Thirumdas, R., Kadam, D., & Annapure, U. S. (2017a). Cold plasma: an alternative technology for

292

the starch modification. Food Biophysics, 12(1), 129-139.

293

Thirumdas, R., Trimukhe, A., Deshmukh, R. R., & Annapure, U. S. (2017b). Functional and

294

rheological properties of cold plasma treated rice starch. Carbohydrate polymers, 157, 1723-

295

1731. https://doi.org/10.1016/j.carbpol.2016.11.050. 12

296

Thirumdas, R., Kothakota, A., Annapure, U., Siliveru, K., Blundell, R., Gatt, R., & Valdramidis, V.

297

P. (2018). Plasma activated water (PAW): Chemistry, physico-chemical properties, applications

298

in food and agriculture. Trends in Food Science & Technology, 77, 21-31.

299

Wongsagonsup, R., Deeyai, P., Chaiwat, W., Horrungsiwat, S., Leejariensuk, K., Suphantharika, M.

300

Fuongfuchat, A., & Dangtip, S. (2014). Modification of tapioca starch by non-chemical route

301

using

302

https://doi.org/10.1016/j.carbpol.2013.10.089.

jet

atmospheric

argon

plasma.

Carbohydrate

polymers,

102,

790-798.

303

Wu, T. Y., Sun, N. N., & Chau, C. F. (2018). Application of corona electrical discharge plasma on

304

modifying the physicochemical properties of banana starch indigenous to Taiwan. Journal of

305

Food and Drug Analysis, 26(1), 244-251. https://doi.org/10.1016/j.jfda.2017.03.005.

306

Zaidul, I. S. M., Norulaini, N. N., Omar, A. M., Yamauchi, H., & Noda, T. (2007). RVA analysis of

307

mixtures of wheat flour and potato, sweet potato, yam, and cassava starches. Carbohydrate

308

polymers, 69(4), 784-791. https://doi.org/10.1016/j.carbpol.2007.02.021.

309

Zhang, B., Chen, L., Li, X., Li, L., & Zhang, H. (2015). Understanding the multi-scale structure and

310

functional properties of starch modulated by glow-plasma: A structure-functionality relationship.

311

Food Hydrocolloids, 50, 228-236. https://doi.org/10.1016/j.foodhyd.2015.05.002.

312 313

Zhu,

F.

(2017).

Plasma

modification

of

starch.

https://doi.org/10.1016/j.foodchem.2017.04.024.

13

Food

chemistry,

232,

476-486.

314 315

Figure 1. Schematic diagram of the experimental setup using atmospheric pressure jet plasma as a

316

tool to modify starch characteristics.

14

100

3500 3000

Viscosity (cP)

2500 60

2000 1500

40 1000

Temperature (℃ )

80

20

500 0

0 0

317 318 319 320

2

6

4

10

8

12

Time (min) native 800W 800W-T1 Figure 2. Changes in the viscosity of native and plasma-treated (at 800W) starch samples (without 800W-T7 temperature

washing) after stored for 0-7 days.

15

321

(A) at a ratio of 1:15 w/v

322 323 324

(B) at a ratio of 1:30 w/v

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Figure 3. Effects of water washing treatment on the viscosity of plasma-treated

327

(at 800W) starch samples after stored for 0 and 7 days.

16

328

(A1) native (control)

(B1) native (control)

329 330

(A2) 400W

(B2) 400W

331 332

(A3) 600W

(B3) 600W

333 334

(A4) 800W

(B4) 800W

335 336

Figure 4. Polarized light and SEM micrographs of native and plasma-treated corn starch

337

samples.

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A1: polarized light micrographs of native corn starch; A2, A3, and A4: polarized light

339

micrographs of corn starches treated with plasma at different strengths (400W, 600W, and

340

800W, respectively); B1: SEM micrographs of native corn starch; B2, B3, and B4: SEM

341

micrographs of corn starches treated with plasma at different strengths (400W, 600W, and

342

800W, respectively). 17

343 344

Table 1. Pasting properties of native and plasma-treated corn starch samples Peak

Trough Breakdown

Treatments

viscosity

Pasting

Final

viscosity

Setback viscosity (cP)

(cP) (cP)

temperature (°C)

(cP)

(cP)

native

3181 a

2055 a

1126 b

3459 a

1404 a

76.20 a

400W

2793 b

1466 b

1327 a

2489 b

1024 b

76.75 a

600W

1451 c

581 c

870 c

972 c

391 c

76.00 a

800W

410 d

141 d

269 d

277 d

136 d

77.08 a

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Values (mean of three determinations) in the same column with different superscripts are significantly

346

different (Duncan, p < 0.05).

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347

Table 2. Swelling power, water soluble index and starch paste clarity of native and plasma-treated

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corn starch samples Treatments

Swelling power (g/g)

Water soluble index (%)

Starch paste clarity (%T)

native

19.14 ± 0.45 a

19.46 ± 1.68 a

15.70 ± 0.13 a

400W

19.35 ± 1.10 a

25.34 ± 2.46 b

17.95 ± 0.07 b

600W

19.22 ± 1.25 a

32.85 ± 2.49 c

20.17 ± 0.37 c

800W

19.23 ± 0.75 a

50.70 ± 3.80 d

29.63 ± 0.21 d

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Values (mean ± SD of three determinations) in the same column with different superscripts are

350

significantly different (Duncan, p < 0.05).

351 352

Highlights

353



Development of an effective way to remove residual aging effects caused by plasma

354



Production of low viscosity starch by atmospheric pressure plasma jet treatment

355



Improvement in paste-cooling stability and reduced retrogradation of corn starch

356



Favorable for applications requiring starch with high paste clarity and solubility

357



A fast and alternative physical approach for starch modification

358 359

19