UNDERSTANDING CEREAL STARCH ARCHITECTURE AND ITS RELATION TO FUNCTIONAL BEHAVIOR AND IMPACT ON HUMAN HEALTH.

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1013187
• Project Start Date: Oct 1, 2017
• Project End Date: Sep 30, 2022
• Program Code: [(N/A)]- (N/A)

Recipient Organization
UNIV OF MINNESOTA
(N/A)
ST PAUL,MN 55108

Performing Department
Food Science & Nutrition

Non Technical Summary
Starch remains a subject of intense scientific scrutiny because of the structural complexity of its molecular make-up, importance in our diet, and impact on human health. Starches from cereals such as corn, wheat, rice and oats have a wide range of applications across various industries in the U.S, mainly due to their different functionalities. Starches from minor cereals such as millet also has the potential to be used in the management of type II diabetes due to their hypoglycemic properties. Understanding the structure of cereal starches is important in the development of new products and understanding their impacts on human health. The project aims at unravelling the complex molecular structure of cereal starches from corn, wheat, rice, millet and oats and how this information can be used to explain their varied behaviours in different food systems. This project will also lead to the understanding of how cereal starches with different fine structural features can be explored in the in the management of conditions such as type II diabetes.

Animal Health Component

(N/A)

Research Effort Categories

Basic

100%

Applied

(N/A)

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
502	1599	1000	100%

Knowledge Area
502 - New and Improved Food Products;

Subject Of Investigation
1599 - Grain crops, general/other;

Field Of Science
1000 - Biochemistry and biophysics;

Keywords

starch structure

human health

glycemic index

Goals / Objectives
Overall goal: To conduct a comprehensive study of the fine structure of selected cereal starches with different genetic and environmental backgrounds and relate it to their functional and glycemic attributes.Specific objectives:To investigate the physical and molecular organization of selected cereal starches from different botanical sources, genetic backgrounds and locationsTo relate the physical and molecular characteristics of cereal starches to their functional and glycemic attributes.

Project Methods
Normal and mutant corn, wheat, millet, rice and oat samples will be milled into flour using the Udy cyclone mill (Udy Corporation. Co. USA) and stored at 4°C. Starches will be extracted from the various cereals according to the method described by Annor et al., 2013 and their amylopectins fractionated using the butanol-isoamyl alchohol method decribed by Klucinec and Thompson (1998). Extacted starches will be analysed for their physical and molecularcharacteristics using the following methods:Starch granule size distributionStarch granule morphology using the scanning electron microscope (SEM)Iodine affinityThermal properties using differential scanning calorimetry (DSC)Crystallinity using wide-angle X-ray diffractionPasting properties using the Brabender micro viscoamylographRheology of cooked starch paste using the Thermo Scientific Roto Visco 1 rheometerResistant starch using the resistant starch kit from Megazyme International IrelandMolecular size distribution using gel permeation chromatography (Sepharose CL-2b and 6B)Molecular size distribution of β-limit dextrinsThe fractionated amylopectins from the starches from the different cereals will be evaluated for their fine structure using methods by Annor et al 2014 and Bertoft et al 2012. The fine structure of the starches will be determined using the anionic exchange chromatographic system coupled to a pulsed amperometric detector (HPAED-PAD). The following will be evaluated:Unit chain profileInternal chain profileClustersBuilding blocksUnit chain profiles will be determined after debranching the starches with starch debranching enzymes. Internal chains will be produced by subsequent hydrolysis of the starches with phosphorylase a and b-amylase. Clusters and building blocks will be produced by hydrolysis of the starches with a-amylase from Bacillus amyloliquefaciens.The starch hydrolysis kinetics and expected glycemic index cooked cereal samples will be evaluated using the method described by Englyst et al. (1992). Hydrolyzed starch will be classified into rapidly digestible starch (RDS), slowly digestible starch (SDS) and resistant starch (RS) (Englyst et al., 1992). The calculations will be as follows: RDS = glucose released at 20 min × 0.9; SDS = (glucose released at 120 min - glucose released at 20 min) × 0.9, and RS = total starch - (RDS + SDS). A non-linear first-order equation C=C∞ (1−e−kt), which was established by Goñi et al. (1997), will be used to describe the kinetics of hydrolysis of the samples. C is the starch hydrolyzed at a chosen time t; C∞ is the equilibrium concentration at the final time (120 min); k is the kinetic constant. The hydrolysis index (HI) will be obtained by dividing the area under the hydrolysis curve (AUC) of the samples by AUC of white bread, which serves as a reference sample, as reported by Goñi et al. (1997). The AUC will be calculated by the equation: AUC = C∞ (tf−to) - (C∞/k) [1−e−k(tf−to)], where tf is the final time and to is the initial time. The eGI will calculated by the equation: eGI = 8.198 + 0.862 *HI as described by Granfeldt et al. (1992)

Progress 10/01/19 to 09/30/20

Outputs
Target Audience:The target audiences reach during this period of reporting are consumers of foods high in carbohydrates and also food industries interested in producing starch based foods that are slowly digested Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Students were trained on the use of enzymes and High Performance Anionic Exchange Chromatography to elucidate the fine structure of starches from different botanical sources How have the results been disseminated to communities of interest?The results had been published as a thesis and we are currently in the process of publishing it in peer reviewed journals What do you plan to do during the next reporting period to accomplish the goals?We will be working more on relating the fine structure of starched to their glycemic index

Impacts
What was accomplished under these goals? The molecular characteristics and amylopectin unit and internal chain profiles of two yellow pea starches (P1 and P2) with significantly different pasting and gelatinization properties were analyzed to investigate the relationship between their functional properties and starch structure. P1 had lower peak, final and setback viscosities but a higher pasting temperature compared to P2. P1 granules gelatinized at higher temperature, but the enthalpy of gelatinization was lower than for P2. Granules from both samples had a unimodal size-distribution averaging 25.4 and 26.5 µm for P1 and P2, respectively. Starches exhibited the typical C-type crystal allomorph with relative crystallinity of 29.8 and 37.5% for P1 and P2, respectively, which correlated with a lower amylose content in P1 granules. The amylopectin components exhibited similar amounts of super-long chains (7.1%) and similar unit chain profiles, but significant differences were observed in their internal chains. P1 with lower pasting viscosities had significantly shorter internal chain lengths, while P2 with lower gelatinization temperature had less A-chains and more of all B-chain categories. The large difference in amylose content and the significantly different internal chain profiles of amylopectin could explain the differences of their functional properties

Publications

• Type: Theses/Dissertations Status: Accepted Year Published: 2020 Citation: Not cited yet

Progress 10/01/18 to 09/30/19

Outputs
Target Audience:The target audience for this research during this reporting audience is the food industry related to starch modification. During this period we investigated how starches from difference botanical sources could be modified with non conventional methods such as Cold Plasma Technology and Chemical Gelatinization and how it affects the functional properties of starches Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?The results have been published in a peer reviewerd journal and also as a thesis at the University of Minnesota Library What do you plan to do during the next reporting period to accomplish the goals?We plan to investigate the effects of Plasma Activated water on the functional and unit cchain profiles of normal, waxy and high amylose starches

Impacts
What was accomplished under these goals? For both objectives, we were able to document the chemical and physical changes that occur when starches from different botanical sources are modified with cold plasma technology and chemical gelatinization. When we treated waxy potato, rice and corn starches with radio frequency cold plasma, we found that final viscosities for all three starches significantly decreased after plasma treatment.Resistant starch significantly increased in waxy maize and potato starch after plasma treatment.Possible formation of V-type single helices was observed in waxy maize and rice as indicated by NMR. Starch damage increased significantly after plasma treatment in waxy potato and maize.

Publications

• Type: Journal Articles Status: Published Year Published: 2019 Citation: Okyere, Akua Yeboah, Eric Bertoft, and George Amponsah Annor. "Modification of cereal and tuber waxy starches with radio frequency cold plasma and its effects on waxy starch properties." Carbohydrate polymers 223 (2019): 115075.

Progress 10/01/17 to 09/30/18

Outputs
Target Audience:This research has been targeted at the food industry involved in the use of starch in various food applications. Results generated on the fine structural characterization of starches has enabled the food industry to better understand the impact of starch structure on its functional uses in foods. Have been working closely witn Cargill Inc and ADM on this project Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Findings from this project was presented at the Annual meeting of the American Association of cereal Chemist by the students involved How have the results been disseminated to communities of interest?Findings from this project was presented at the Annual meeting of the American Association of cereal Chemist What do you plan to do during the next reporting period to accomplish the goals?Work will be done to understnd how cereal starched can be modified using non-thermal methods

Impacts
What was accomplished under these goals? Intermediate wheatgrass (IWG) (Thinopyrum intermedium) is an environmentally sustainable perennial crop with potential food applications. This study investigated the starch hydrolysis kinetics of IWG grown in Roseau (IWG-RS) and Rosemount (IWG-RM), Minnesota, USA and its effects on the unit chain profile of its resistant starch (RS) fraction. Hard red wheat (HRW) and Jasmine rice (JR) were compared to the IWG samples. Cooked flour and extracted starches were hydrolyzed with a mixture of pancreatic alpha amylase and amyloglucosidase, and their rapidly (RDS), slowly (SDS) digestible and resistant (RS) starch on starch basis determined. Expected glycemic index (eGI) and chemical composition of samples were also determined. Molecular size distribution and unit chain profiles of the RS fraction of raw starches after enzymatic hydrolysis were determined with gel permeation chromatography and high-performance anion-exchange chromatography respectively. IWG flour had significantly lower total starch, higher RS, lower RDS and higher lipid contents compared to JR and HRW. RDS of samples ranged from 20.7 to 27.3% and 30.5 to 35.2 % for samples respectively. JR flour had the highest eGI (49.2), with IWG-RM recording the lowest (40.6). Significant differences were observed in the glucan chain lengths of the RS starch fraction. JR had the shortest average chain length (DP = 4.75) compared to HRW (DP 7.46), IWG-RS (DP=5.72) and IWG-RM (DP 4.85). IWG flour had slower starch hydrolysis kinetics compared to JR and HRW flour. The resistant starch fraction of the samples consisted mostly of long chains. The glucan chain length of IWG RS fraction was also significantly affected by location.

Publications

• Type: Journal Articles Status: Submitted Year Published: 2019 Citation: N/A