Recipient Organization
KANSAS STATE UNIV
(N/A)
MANHATTAN,KS 66506
Performing Department
Grain Science And Industry
Non Technical Summary
Whole grain contains the entire kernel components, including endosperm, bran, and germ and is excellent sources of many essential nutrients (e.g., dietary fiber, proteins, vitamins, minerals, antioxidants, phytochemicals). Diets rich in whole grains are associated with a reduced risk of coronary heart disease, cardiovascular disease, type 2 diabetes, obesity, and certain cancers (Aune et al. 2016). The 2015-2020 Dietary Guidelines recommend at least half of daily grain foods as whole grains (≥ 3-ounce of the equivalent/day), but most Americans still favor refined grain foods over whole grain products. It is estimated that only 10 to 12% population consumes the recommend amount of whole grains. Barriers to whole grain consumption include product availability, palatability, appearance, cost, shelf life, convenience, etc. (Marquart et al. 2013).Wheat products are among the most important whole grain source, but we are still facing several major challenges to deliver quality whole wheat foods. Whole wheat flour production accounted for only 5% of U.S. flour production in 2016. Sophisticated and standardized whole wheat milling technologies need to be developed and established. Shelf-life of whole wheat flour is much shorter than refined flour, caused by lipid degradation and other enzymatic and non-enzymatic reactions during storage. The formulation and processing of whole grain products differ from refined flour products and could be more challenging due to the presence of bran and germ components. For example, whole wheat flour dough is stickier than refined flour dough, which limits its processing efficiency in industrial bakery production. Most consumers still prefer refined flour products over whole grain products, such as bread, partly because of the distinct sensory attributes like grittiness, firmer texture, slightly bitter taste, dark color, etc., of whole wheat products. The underlying mechanisms responsible for the detrimental effects of bran and germ on whole grain products are lacking. Frozen dough and other bake-off products (e.g., pre-proofed frozen dough, pre-baked bread) have been fast growing bakery segments due to manufacturing and economic advantages; however, little research information is available on the formulation, storage stability, and quality of whole grain bake-off applications. Hence, there is an urgent need for cereal scientists and food industries to develop feasible solutions to overcome these barriers and fill the gaps in order to deliver palatable, convenient, and healthy whole grain products that meet consumer's needs and ultimately increase whole grain consumption.This project will address some challenges of whole grain wheat products, particularly focusing on improving whole wheat flour storage-stability, dough rheological properties, and bread texture, developing whole wheat frozen doughs, understanding fundamental salt functions in whole wheat products, and improving the antioxidant potential of whole wheat bread. Our research will contribute both foundational knowledge and applied information to other cereal scientists and food industries in the field for the development of superior whole grain products. It will provide new insights on delivering quality whole grain products with sensory, quality, nutrition, and health advantages that consumers will like and ultimately increase whole grain consumptions to meet the Dietary Guidelines recommendations. Ph.D. and MS graduate students, undergraduate researchers and postdoc will be trained through this project to obtain advanced knowledge and gain hands-on research skills in cereal food chemistry.
Animal Health Component
20%
Research Effort Categories
Basic
70%
Applied
20%
Developmental
10%
Goals / Objectives
Our long-term goal is to deliver whole wheat flours with better storage stability and develop healthy whole grain bakery products with superior quality that meet American's sensory and health needs. The objectives of this project are to:1. Improve storage stability of whole wheat flours through novel treatments (e.g., high pressure, pulsed electric field, ultrasound) (project#1). Whole wheat flour contains more enzymes and lipids than refined flour, and therefore, deteriorates much faster during storage. Shelf-life of whole wheat flour is around 3-9 months, while refined flour could be stable for 9-15 months after milling (Doblado-Maldonado et al. 2012). Lipid degradation is the predominant cause of whole flour deterioration, which usually starts with hydrolytic rancidity catalyzed by lipase, and followed by enzymatic- and auto-oxidation. Therefore, inactivation of lipase is a major approach to improve whole wheat flour storage stability. A number of heat processing (e.g., dry heat, steam, microwave treatment) has been found effective in inhibiting lipase activity (Rose et al. 2008); however, thermal treatment may increase lipid autoxidation and decrease flour functionality. Novel food processing technologies like high pressure, ultrasound, and pulsed electric field could inactivate many enzymes without significant increase of temperature. We hypothesize that lipase could be inactivated through these treatments to improve whole wheat flour shelf-life while flour functionality could be retained. The sub-objectives of this project are to: 1) study the effect of high pressure, ultrasound, or pulsed electric field treatment of whole wheat flours or brans on lipase activity; 2) study treated whole wheat flour shelf-life; and 3) study dough rheological properties and bakery quality of treated whole wheat flours.2. Develop whole wheat doughs and bread with desired rheological properties and texture using dough improvers (e.g., hydrocolloids, emulsifiers, enzymes) (project#2). Bran and germ components in whole wheat flours interfere with gluten network formation and viscoelastic dough development during dough mixing and fermentation, leading to undesirable dough properties. Whole wheat bread usually has a smaller volume, firmer and courser (i.e., grittier) texture, and faster staling compared with refined flour bread, which prevents many consumers from consuming whole grain bread. Various dough improvers and additives, including hydrocolloids, emulsifiers, oxidizers, and/or enzymes have long been used to improve dough properties and bread quality, particularly in bakeries from refined flours and gluten-free formulas. However, much less information is available in improving whole wheat dough and bread with such additives. A fundamental understanding of the molecular-level changes in gluten and starch resulting from the interactions with hydrocolloids, emulsifiers, or enzymes is lacking. The sub-objectives of this project are to: 1) study the effect of hydrocolloids on whole wheat dough properties, gluten/starch microstructures, and bread quality; 2) study the effect of emulsifiers on whole wheat dough properties, gluten/starch microstructures, and bread quality; 3) study the effect of enzymes on whole wheat dough properties, gluten/starch microstructures, and bread quality; and 4) optimize dough formulas combining different additives for superior dough properties and bread quality.3. Develop whole wheat frozen doughs with desired storage stability and baking quality (project#3). Frozen dough is one of the fastest growing bakery segments. It has the economic advantages of centralized manufacturing and distribution process and standardization of product quality. However, frozen dough quality gradually deteriorates during storage, leading to inferior bakery texture. Many studies have been conducted to minimize quality loss of frozen dough during storage by using dough improvers and controlling processing variables. However, nearly all the previous studies are based on refined flour frozen dough, and little information is available on whole grain flour frozen dough (Bae et al. 2014). In addition, the fundamental understanding of gluten structural changes during frozen storage is lacking. The sub-objectives of this project are to: 1) study the effect of various hydrocolloids, emulsifiers, enzymes, and other dough improvers on the storage stability of whole wheat frozen doughs and optimize the formulation; 2) evaluate the baking quality of whole wheat flour frozen doughs; and 3) understand the structural changes of gluten during frozen storage.4. Improve the fundamental understanding of salt functions in whole wheat dough and bread for sodium reduction (project#4). Sodium reduction is a top health trend currently. Cereal based products contribute 35% of daily sodium intake. Reducing sodium salt in bread could be a critical step to achieve the national sodium reduction goal and ultimately improve our health and well-being. However, lack of fundamental knowledge regarding salt's functions in dough and bread has been a limiting factor in developing appropriate salt reduction strategies for bakery products. In addition, no previous studies were conducted to investigate the function of salt in whole grain wheat dough and bakeries. The sub-objectives of this project are to: 1) study the effect of salt on the physical and rheological properties of whole flour doughs and bread quality; 2) understand salt induced molecular interactions in dough and bread (particularly associated with gluten proteins) at different stages (i.e., dough development, bread-baking, bread storage); and 3) develop quality whole grain wheat bread with reduced sodium salt.5. Improve antioxidant potential of whole wheat bread through manipulated Maillard reaction (project#5). During baking of bread dough, Maillard reaction occurs between carbonyl groups of reducing carbohydrates and amino groups of proteins, peptides, and amino acids, and generates melanoidin, which are generally associated with high antioxidant activities and other health promoting benefits. Melanoidin amount and composition and antioxidant activity are affected by food system composition (e.g., content of available reducing sugars and amino groups), processing methods and parameters (e.g., processing temperature and time), pH, moisture, etc. Bread is one of the most popular bakery foods and accounts for over 35% of total bakery consumption. However, very limited information is available on the antioxidant activities of melanoidingenerated during bread baking. Moreover, the specific compounds of melanoidinresponsible for the antioxidant activity are not yet clear. Our preliminary study found that more melanoidinsare generated during baking of whole wheat flour doughs with a much stronger antioxidant activity (excluding phenolic effect) compared with refined flour dough. The sub-objectives of this project are to 1) study the effect of reducing sugars and baking conditions on melanoidin and antioxidant activity of whole wheat bread; 2) study the effect of amino acid and baking conditions on melanoidin and antioxidant activity of whole wheat bread; and 3) characterize the compositions of melanoidinand study structure-antioxidant activity relationships.
Project Methods
Project#1. Improve storage stability of whole wheat flours. Fresh milled whole wheat flours and brans will be treated using high pressure, pulsed electric field, or ultrasound for different times under varied intensities. Lipase activity will be determined immediately after treatment according to (Rose and Pike 2006). Treated flours will be stored under accelerated conditions for different periods (0 to 6 months), with untreated flours used as the control. Lipid degradation products will be evaluated at different storage points using gas chromatography. Dough properties and bread baking quality of both treated and control whole flours will also be evaluated at different storage times. Dough physical and rheological properties will be determined using Mixograph, Farinograph, TA-XTPlus texture analyzer, and Malvern rheometer. Whole wheat bread will be baked according to AACC approved method 10-10.03. Bread volume, color, texture, and cell distribution will be determined using rapeseed displacement, colorimeter, TA-XTPlus texture analyzer, C-Cell image analyzer, and X-ray microtomography, respectively.Project#2. Develop superior whole wheat flour doughs and bread. Whole wheat flour will be obtained from commercial mills. Typical bakery hydrocolloids (xanthan, guar gum, sodium alginate, κ-carrageenan, hydroxy propyl methylcellulose), emulsifiers (e.g., sodium stearoyl lactylate, diacetyl tartaric acid ester of monoglycerides, lecithin, sucrose esters), and enzymes (cellulases, hemicellulases, pentosanases, laccase, lipase, amylase, xylanase) will be added to whole wheat flour at different ratios, respectively. Water absorption will be optimized through Mixograph and Farinograph. Dough properties including strength, extensibility, stickiness, and viscoelasticity will be measured using TA-XTPlus texture analyzer and Malvern rheometer. Gluten and starch microstructural changes induced by these additives will be characterized by HPLC, FTIR, UV-Vis spectrophotometer, and differential scanning calorimetry. Bread will be baked per AACC approved method 10-10.03. Bread quality will be determined similarly as previously described.Project#3. Develop whole wheat flour frozen doughs. Results from project#2 will provide important guidance on the formula of whole wheat flour frozen doughs. Doughs will different additives (hydrocolloids, emulsifiers, enzymes, oxidation agents) will be prepared, respectively. Doughs will be frozen immediately after mixing and resting, packed and stored in plastic bags at -20 °C for up to 60 days. Dough and bread properties will be evaluated similarly as previously described. Gliadin/glutenin changes during frozen dough storage will be determined using reverse-phase HPLC (HP1050 Series). Amount of free sulfhydryl and disulfide groups will be measured using VWR UV-6300PC spectrophotometer. Gluten secondary structures will be determined using PerkinElmer Spectrum 400 FT-IR/FT-NIR Spectrometer equipped with an ATR accessory. Starch gelatinization and retrogradation will be measured using TA Q200 DSC.Project#4. Fundamental understanding of salt functions and sodium reductions. Whole wheat doughs and bread with different levels of salt (0 - 2%) will be prepared. Optimal water absorption and mixing time of each dough system will be determined using Mixograph. Dough strength and extensibility and stickiness will be determined using a TA.XT Plus Texture Analyzer with different rigs. Rheological properties will be measured using Malvern rheometer. Confocal laser scanning microscopy will be used to obtain the visual distribution of gluten networks and starch particles as a function of salt. Whole wheat bread will be baked and evaluated similarly as previously described. Gluten structural properties (gliadin/glutenin, disulfide and sulfhydryl content, secondary structure, hydrophobicity, and surface charge) as a function of salt will be characterized. Reduction of sodium using salt substitutes (e.g., potassium chloride) or flavor enhancers will be tested and optimized in whole grain bread formulas.Project#5. Maillard reaction products as antioxidants in whole wheat bread. Different levels of reducing sugars (glucose, maltose, galactose, lactose, ribose, xylose, raffinose) and amino acids (lysine, alanine, tryptophan, glycine, asparagine, glutamic acid) will be added into whole wheat dough formula, respectively. Baking time and temperature will be varied to investigate their effect on melanoidin formation and antioxidant activity. Bread quality (volume, texture, cell distribution, color) will be evaluated similarly as previously described. Melanoidin will be extracted using the method described in (del Castillo, Ames and Gordon 2002) with some modifications. Amount of extracted melanoidin will be determined using VWR UV-6300PC spectrophotometer at 420 nm. Antioxidant activity will be evaluated using DPPH assay. Melanoidin will be separated into different molecular size fractions using membrane filtrations with different size cut-off limits. Chemical compositions of melanoidin will be characterized using GC-MS.