Source: UNIVERSITY OF MISSOURI submitted to
IMPROVING FUNCTIONAL PROPERTIES OF DAIRY INGREDIENTS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0233858
Grant No.
(N/A)
Project No.
MO-HAFE0021
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Feb 1, 2013
Project End Date
Jan 31, 2018
Grant Year
(N/A)
Project Director
Vardhanabhuti, B.
Recipient Organization
UNIVERSITY OF MISSOURI
(N/A)
COLUMBIA,MO 65211
Performing Department
Food Systems & Bioengineering
Non Technical Summary
Dairy proteins such as milk protein concentrate (MPC) and whey protein isolate (WPI) as well as their by products have become the major ingredients used in foods especially in sports drinks and nutritional products. The market for the dairy ingredients has increased both domestic and international. The US is the major exporter of whey protein which was valued at almost $ 1 billion in 2012. Increase in consumption and sales of these products will benefit the dairy industry as well as the dairy farmers. Our project aims at improving the functional properties of dairy ingredients in order to increase their utilization. The first part of the project will focus on optimizing and improving the baking properties of milk protein concentrate. Currently, MPC is not used as the main foaming ingredient in bakery products due to the collapse of protein network during baking resulting in collapsed cake. Our approach is to utilize milk permeate (the by-product of MPC manufacturing) to improve baking properties of MPC. The second part of the project will focus on improving heat stability of whey protein. Formation of complexes between whey protein and polysaccharides has been shown to improve heat stability; however, most food-grade polysaccharides have high molecular weight which lead to complexes with large size. We will apply high power ultrasound to produce polysaccharides with lower molecular size. Our approach is to optimize whey protein and polysaccharide interactions that provide maximum heat stability.
Animal Health Component
(N/A)
Research Effort Categories
Basic
(N/A)
Applied
(N/A)
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
5013470100050%
5023470100050%
Goals / Objectives
Dairy proteins such as whey proteins and milk protein concentrate (MPC) have become the major ingredients used in foods and beverages due to their high nutritional values and versatile functional properties. Whey proteins are mainly used in sports beverages and nutritional bars, while MPC is mainly utilized in sports and nutrition drinks as well as processed cheeses. Improving functional properties of dairy proteins will lead to increased their utilization which will benefit the industry as well as farmers. My overall goal is to investigate the underlying molecular properties that are responsible for their functional properties and to find ways to improve their properties. One potential application of MPC is to utilize their foaming properties. Currently, egg white protein is the major ingredient used in baking products. However, due to the outbreaks of food-borne diseases related to egg products, there is an interest in alternative protein source. The first part of the project is to improve foaming properties of MPC for baking application. We will start by studying the effects of different factors on foaming properties of MPC. Then we will investigate the baking properties of MPC in angel food cake in comparison to egg white protein. Finally, we will select the conditions that provide good foaming properties (overrun and stability) and investigate the effect of milk permeate on angel food cake properties made by using MPC as foaming ingredient. The focus of the second part of the project will be on improving heat stability of whey proteins. With continuing growth in the sales of functional beverages, there is a need to develop whey protein with improved heat stability. Our approach is to utilize protein and polysaccharide electrostatic and covalent interactions. We will use high power ultrasound to decrease molecular weight of anionic polysaccharides. These polysaccharides will interact with whey proteins via electrostatic interaction at near neutral pH. By heating mixtures of whey proteins and polysaccharides, we expect to form heated soluble complexes of the biopolymers that are more heat stable. By using ultrasound-treated polysaccharides, we could investigate the effect of molecular size, and by using polysaccharides with different charge density, the effect of charge can be determined. Another approach is to form covalent conjugate of WPI and anionic polysaccharide (with or without ultrasound treatments). By combining the covalent and electrostatic interaction, we expect to create complexes with much improved in heat stability and possibly other functional properties. Specific objectives: 1. Determine factors affecting foaming properties of MPC. 2. Determine the effect of MPC on replacing egg white protein in angel food cake 3. Determine the effect of milk permeate on baking properties of milk protein concentrates in angel food cake. 4. Determine the effect of high power ultrasound on heat stability and other functional properties of whey protein and polysaccharide complexes. 5. Determine the effect of high power ultrasound on heat stability and other functional properties of whey protein and polysaccharide covalent conjugate.
Project Methods
I. Improving foaming properties of MPC. MPC solutions will be prepared at 10-15% protein, pH (5.5 - 7.5), salt types and concentrations (NaCl or CaCl2 at 0 - 200 mM), and under no heat or pre-heating. Egg white protein (EWP) solution will be prepared at 10% protein at pH 7.0. Interfacial properties of the protein solutions will be determined using a rheometer. Foam will be generated by whipping protein solutions with a KitchenAid mixer. Foaming properties before cake batter preparation will be evaluated by measuring the overrun, drainage half-life, and foam viscoelasticity. For angel food cake, conditions that produce good foaming properties will be selected. Foams will be generated from protein solutions (200 mL) and dry materials (flour, powdered sugar, milk permeate, and gums) will be gently mixed into the foams. The amount of flour will be 66 g for all treatments. Sugar content will range from 0 - 128 g/mL protein solution. Milk permeate will range from 0 - 20 g. Gums used will be xanthan gum, guar gum, maltodextrin, and inulin. The amount of gum will range from 0 - 1 g. The batter will be baked. By varying protein concentration, pH, salt type and concentration and heating, we will be able to determine how different factors affect foaming properties of MPC (Objective 1). By varying the ratio of MPC and EWP, we will be able to compare MPC and EWP as well as how sugar affects the baking properties of both proteins (objective 2). We expect milk permeate to prevent the cake from collapsing. The relationship between milk permeate concentration, batter rheological properties and cake properties will be established (objective 3). II. Improving heat stability of whey protein. Whey protein isolate (WPI) having > 90% protein will be used. Pectins having ranges of negatively charge will be used in order to investigate the effect of charge interaction. Pectin stock solutions will be made and subjected to high power ultrasound (1000 W) for 0, 30, 60, and 90 min. The change in particle size distribution and zeta potential will be recorded. Stock WPI solution (15% protein) will be prepared. In order to test heat stability, appropriate amount of WPI and polysaccharide stock solutions will be mixed such that the final mixtures contain 3-7% protein, 0-1% polysaccharide, 0-100 mM NaCl or 0-20 mM CaCl2 at pH 6-7. The mixtures will be heated and characterized as followed. Particle size, turbidity, rheological properties, and zeta potential will be measured. In a separate set of study, WPI and polysaccharides (with and without ultrasound treatments) will be mixed to a 0:0 to 20:1 protein:pectin ratios. The solutions will be adjusted to pH 6 to 7 and freeze dried. The dried powders will be subjected to Maillard reaction by incubating at 60 or 85oC for 2, 6, 12, 24, and 48 h. This will result in conjugation of WPI and pectin. The resulting conjugates will be characterized as previously described. At the end of this study, we should be able to determine the best approach to improve heat stability of whey protein. We should be able to establish the optimum conditions for complex formation either via covalent or electrostatic.

Progress 02/01/13 to 01/31/18

Outputs
Target Audience:Academia and food science professionals. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?One PhD and 3 MS students were trained during the project. Each had at least one published manuscript. In addition, three undergraduate students were trained. All had one poster presentation at professional meeting. List of students is listed. How have the results been disseminated to communities of interest?The results of this project were disseminated to community of interest through following ways: (i) publications of abstracts followed by oral or poster presentations at various international and national conferences, (ii) delivering invited presentation and communicating with industry. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Impact Dairy proteins are the major ingredients used in foods and beverages.The US is the major exporter of whey protein with value over $1 billion yearly.Increase in utilization and sale of these products will benefit the dairy and food industry as well as dairy farmers.Thiscan be accomplished by technologies that improve functional properties of dairy proteins so that they can be utilized in a wider range of applications.This research has developed whey protein-based ingredients that have improved foaming properties and emulsification properties.In addition, the study also identified factors that lead to improved foaming properties of milk protein ingredient. Objectives 1.Determine factors affecting foaming properties of milk protein concentrate (MPC). Calcium chloride and/or sodium citrate were mixed with MPC solutions and pH was adjusted such that the final solutions contained 5% w/w protein, 0-20 mM CaCl2and 0-40 mM citrate at pH 7.0. Foaming properties were determined by measuring overrun and drainage ½ life. Physical properties of pre-foam solutions, including solubility, turbidity, and particle size were measured.Foam rheology was determined using a controlled- strain and rate rheometer.Results showed that addition of 20 mM CaCl2caused a reduction in overrun (P < 0.05) but no significant effect on foam stability. Either with or without of CaCl2, increasing citrate concentration significantly increased the overrun (P < 0.05) and drainage ½ life of MPC foams. However,higher citrate concentration (40 mM) only showed improvement in overrun but a decrease in drainage ½ life. Enhanced overrun corresponded to a reduction in particle size and turbidity and an increase in solubility of pre-foam solutions. Pre-foam solutions with CaCl2exhibited higher interfacial viscosity and interfacial elastic modulus, while the presence of citrate reduced interfacial viscosity and interfacial elastic modulus. These results indicated that through appropriate concentrations and combination of salts the foaming properties of MPC could be optimized. Key outcome: New knowledge in foaming properties of MPC was presented. This could lead to increased utilization of MPC. Objective 2. Determine the effect of MPC on replacing egg white protein in angel food cake. Objective 3. Determine the effect of milk permeate on baking properties of milk protein concentrates in angel food cake. Foam of egg white protein isolate (EWI) and preheated (55oC) MPC solutions at different ratios were preparedin a KitchenAid mixer.Results showed that foam overrun and drainage significantly decreased with 20% EWI replacement. No change in overrun was observed with increasing MPC ratio (P> 0.05) while drainage increased. Similar trend was observed with yield stress of cake batter. When used in angel food cake, replacing 20% EWI did not significantly affect cake volume, chewiness or gumminess (P> 0.05) though hardness decreased by 12% and springiness increased by 14%. At 40% replacement cake volume significantly decreased and continued to decrease at higher %MPC. Largest changes in TPA attributes were observed at 40% replacement. At higher MPC ratios, the cakes were too dense such that hardness and gumminess started to increase.Addition of milk permeate at 2.5 to 5% by mixing in with flour and sugar could lead to improved cake volume. Key outcome: We presented baking properties of MPC and the approach to maximize their uses in bakery products. Objective 4. Determine foaming properties of WPI and polysaccharide heated complexes. The first research towards this objective was to compare foaming properties mixed WPI and λ-carrageenan (λC) in different systems. Three WPI and λC systems were prepared: 1) heated WPI and λC soluble complex (h-CPX), (2) heated WPI with added λC (pWPI+λC), and (3) unheated WPI with λC. Results showed that both h-CPX and pWPI+λC foams showed improved overrun and stability (P < 0.05) compared to unheated WPI at similar λC concentrations. At 0.025% λC, h-CPX foams were significantly more stablecompared to pWPI+λC foams. Foam rheology results showed that both h-CPX and pWPI+λC foams were more elastic than unheated WPI foams. CLSM analysis revealed that h-CPX foams were composed of smaller bubbles and showed slower rate of disproportionation compared to pWPI+λC foams, corresponding to foam stability results. We also investigated the use of WPI and polysaccharide heated complexes in aerated dairy gels. Results showed that overrun of aerated gelsignificantly decreased as polysaccharide concentration increased due to increased viscosity which limited air incorporation. Increased concentration was significantly related to increased stability (P < 0.001) which could be due to increased viscosity of the pre-foam solutions limiting the mobility of the air bubbles. Charge density played an important role on stability. Plot of drainage against solution viscosity revealed that drainage was lowest in samples with high charge density pectin (LM-12). Aerated gels with guar gum (no charge) did not show improvement to stability even at highest guar concentration. Key outcomes:Heated WPI and polysaccharide complexes can be developed with significant improvement in foaming properties.Two manuscripts were published. Objective 5.Determine acid-induced gelation properties of heated WPI-polysaccharides complexes. We investigated the effect of charge density (pectins), molecular weight (carboxymethylcellulose) and concentration of polysaccharides, as well as pH. Results showed that acid-induced gels made by heated soluble complexes at pH 7.0 had significantly improved gel strength than the traditional heated WPI with added pectin gels (polymer/pectin gels). Pectin with high charge density led to gels with higher water holding capacity. The enhanced electrostatic interactions between whey proteins and pectin during heating led to finer gel microstructure formation with less porosity and smoother gel network. For the study using CMC with varying molecular weight, our study concluded that the effect of molecular weight was less significant. Key outcomes:Our studies indicated that, under optimum preparation conditions, heated WPI and polysaccharide soluble complex can be used as novel ingredients in cold-gelation applications such as yogurt.Three manuscripts were published. Objective 6. Determine the emulsification properties of heated WPI and pectin complexes We found that heated WPI-pectin complexes also had improved emulsification properties. Biopolymer ratio and heating conditions influenced the properties of the ingredients; thus, their emulsification properties can be optimized for various types of emulsions (e.g., different oil content). Heated complexes showed similar emulsifying properties as synthetic emulsifiers but the emulsions stabilized by the heated complexes were significantly more stable. Key outcome: Heated complexes can be used as emulsifier and stabilizer in clean label applications. It should be noted that, originally, objectives 4 and 5 aimed at investigating the effect of ultrasound on functional properties of protein and polysaccharide complexes.Our preliminary results showed that ultrasonic treatment may not lead to significant change. Thus, objectives 4 and 5 have been restated and results described as shown above.

Publications

  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Huan, Y. and Vardhanabhuti, B. Acid-induced gelation of heated soluble whey protein isolate and CMC particles. Institute of Food Technologists Annual Meeting, July 2013, Chicago, IL.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Zhang, S. and Vardhanabhuti, B. Improved Acid-induced Gelation Properties of Whey Protein by Heated Whey Protein/Pectin Soluble Complex. Institute of Food Technologists Annual Meeting, July 2013, Chicago, IL.
  • Type: Theses/Dissertations Status: Published Year Published: 2015 Citation: He, Y. 2015. Improved heat stability of whey protein isolate by glycation with inulin. Master thesis, University of Missouri.
  • Type: Theses/Dissertations Status: Published Year Published: 2014 Citation: O'Chiu, E. 2014. Application of whey protein-polysaccharide complexes in aerated dairy gels. Master thesis, University of Missouri.
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Wang, Z., Zhang, S., and Vardhanabhuti, B. 2015. Foaming Properties of Whey Protein Isolate and ?-Carrageenan Mixed Systems. J. Food Sci. 85(8): N1893-N1902.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Huan, Y., Zhang, S. Effect of CMC Molecular Weight on Acid-Induced Gelation of Heated WPI-CMC Soluble Complex. J Food Sci. 2016 Feb;81(2):N502-76
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: He, Y. and Vardhanabhuti, B. 2015. Improved heat stability of whey protein isolate by glycation with inulin. American Dairy Science Association Annual Meeting, July 2015.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Huan, Y., Zhang, S., & Vardhanabhuti, B.* 2016. Influence of the molecular weight of carboxymethylcellulose on properties and stability of whey protein-stabilized oil-in-water emulsions. Journal of Dairy Science. 99(5): 3305-3315.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: O'Chiu, E., & Vardhanabhuti, B. (2017). Aerated dairy gels stabilized by heated whey protein isolate and pectin complexes. Journal of Dairy Science, 100, 3404-3412.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Wang, Y., & Vardhanabhuti, B. (2017, June). . Improving emulsification properties of whey protein isolate by heating with pectin at near neutral pH. Presented at the American Dairy Science Association Annual Meeting, Pittsburge, PA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Kotchabhakdhi, A., & Vardhanabhuti, B. (2017, July). Formation of heated WPI-pectin complexes at pH > pI with improved emulsification properties. Presented at the IFT Annual Meeting, Las Vegas, NV.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Khumsangkla, S., & Vardhanabhuti, B. (2017, June). Formation and characterizations of heated whey protein isolate and alginate complexes. Presented at the American Dairy Science Association Annual Meeting, Pittsburge, PA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Sukkha, P., Kotchabhakdi, A., & Vardhanabhuti, B. (2017, June). Influence of heated whey protein isolate and pectin complex on properties and stability of O/W emulsions at different pH. Presented at the American Dairy Science Association Annual Meeting, Pittsburge, PA.
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Zhang, S., Hsieh, F. H., & Vardhanabhuti, B. (2014). Acid-induced gelation properties of heated whey proteinpectin soluble complex (Part I): Effect of initial pH. Food Hydrocolloids, 36, 76-84.
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Zhang, S., & Vardhanabhuti, B. (2014). Effect of initial protein concentration and pH on in vitro gastric digestion of heated whey proteins. Food chemistry, 145, 473-480.
  • Type: Theses/Dissertations Status: Published Year Published: 2014 Citation: Zhengshan Wang. FOAMING PROPERTIES OF WHEY PROTEIN ISOLATE AND LAMBDA CARRAGEENAN MIXED SYSTEMS. Master thesis, University of Missouri.
  • Type: Theses/Dissertations Status: Published Year Published: 2015 Citation: Yan Huan. APPLICATION OF SOLUBLE WHEY PROTEIN-CARBOXYMETHYLCELLULOSE COMPLEX IN EMULSION AND ACID-INDUCED GELATION. Master thesis, University of Missouri.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Wang, Z. and Vardhanabhuti, B. Foaming Properties of Whey Protein Isolate and lambda-Carrageenan Mixed Systems. Institute of Food Technologists Annual Meeting, July 2013, Chicago, IL.


Progress 10/01/17 to 01/31/18

Outputs
Target Audience: Nothing Reported Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?One graduate student was working on the project. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Impact Novel biopolymer-based ingredients with improved emulsification properties can be utilized as emulsifier in clean-label applications. Previously, we developed whey protein and pectin complexes (HCPX)with improved emulsification properties. In this reporting period, we compared the emulsification properties ofthese complexesto synthetic emulsifiers. Commercial emulsifiers used were Tween 20 (Fisher Scientific, Fair Lawn, NJ), Tween 80 (Acros Organics, Fair Lawn, NJ) and DimodanâPH 320 K-A MB (Dupont, New Century, KS). Emulsions contained 5 or 20% and 1.5 or 2% protein and were at pH 5.0 or 5.5. Results showed that though commercial emulsifiers could form emulsions with good characteristics (e.g., small droplet size with charged surface), the emulsions were less stable compared to those stabilized by the HCPX. Key outcome: HCPX could be used as emulsifier and stabilizer in food emulsion with clean label.

Publications


    Progress 10/01/16 to 09/30/17

    Outputs
    Target Audience:The research work was mainly focused to benefit the US dairy industry and the US food industry. Research outcomes will be useful to improve the functionality of dairy and food products with clean label as well as help design food with better nutritional properties which will benefit general public. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Three graduate (MS) students and two undergraduate students have been trained in this research project. How have the results been disseminated to communities of interest?The results of this project were disseminated to community of interest through following ways: (i) peer-reviewed publications in the scientific journals (ii) publications of abstracts followed by oral or poster presentations at various international and national conferences (iii) delivering invited and keynote presentations at various workshops, Symposia and Scientific and industry conferences (iv) discussions at various industry meetings. What do you plan to do during the next reporting period to accomplish the goals?I plan to continue investigating the properties of heated WPI and polysaccharide ingredients especially in baking applications. Additionally, research results will be applied in real food applications. With continued consumers' interest inclean label products, our research will fullfill the needs for the dairy and food industry in developing the ingredients for clean label applications.

    Impacts
    What was accomplished under these goals? Heated whey protein isolate (WPI) and pectin ingredients with improved foaming and emulsification properties were developed by heating the biopolymers at near neutral pH (e.g., pH 5.5 to 7). The effects of polysaccharide types, biopolymer ratios, pH and heating were studied. Heating WPI and low methoxyl pectin at pH 7 forms ingredients that could stabilize aerated gels made with skim milk powder. These ingredients also showed improved emulsification properties compared to that of protein alone. Biopolymer ratio and heating conditions influenced the properties of the ingredients; thus, their emulsification properties can be optimized for various types of emulsions (e.g., different oil content). In conclusion, heated WPI and polysaccharide ingredients with improved functional properties can be utilized in clean label applications.

    Publications

    • Type: Journal Articles Status: Published Year Published: 2017 Citation: O'Chiu, E., & Vardhanabhuti, B. (2017). Aerated dairy gels stabilized by heated whey protein isolate and pectin complexes. Journal of Dairy Science, 100, 3404-3412.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Wang, Y., & Vardhanabhuti, B. (2017, June). . Improving emulsification properties of whey protein isolate by heating with pectin at near neutral pH. Presented at the American Dairy Science Association Annual Meeting, Pittsburge, PA.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Kotchabhakdhi, A., & Vardhanabhuti, B. (2017, July). Formation of heated WPI-pectin complexes at pH > pI with improved emulsification properties. Presented at the IFT Annual Meeting, Las Vegas, NV.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Khumsangkla, S., & Vardhanabhuti, B. (2017, June). Formation and characterizations of heated whey protein isolate and alginate complexes. Presented at the American Dairy Science Association Annual Meeting, Pittsburge, PA.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Sukkha, P., Kotchabhakdi, A., & Vardhanabhuti, B. (2017, June). Influence of heated whey protein isolate and pectin complex on properties and stability of O/W emulsions at different pH. Presented at the American Dairy Science Association Annual Meeting, Pittsburge, PA.


    Progress 10/01/15 to 09/30/16

    Outputs
    Target Audience:Food/Dairy Industry. Academia. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?One MS student was tranied on these research projects. How have the results been disseminated to communities of interest?In addition to the publications, we have previously presented the research findings at the Institute of Food Technologists Annual Meeting and the American Dairy Science Assoication Annual Meeting. What do you plan to do during the next reporting period to accomplish the goals?We will focus on other functional properties of the heated protein and polysaccharide complexes.

    Impacts
    What was accomplished under these goals? We have explored the electrostatic complexation between whey protein isolate and carboxymethyl cellulose (CMC). In acid-induced gelation application, heated whey protein and CMC soluble complex were investigated as a function of CMC molecular weight (270 k, 680 k, and 750 kDa) and concentrations (0 - 0.125%). Gel hardness increased with increasing CMC concentrations in a certain range, but decreased with higher CMC content. Gels with low CMC concentration showed homogenous microstructure and were independent of CMC molecular weight, while increasing CMC concentration led to micro-phase separation with higher CMC molecular weight showing more extensive phase separation. Gels made from heated complex formed at higher protein concentration showed improved gel hardness and water holding capacity, which was supported by the more interconnected protein network with less porosity. In emulsion application, mixed WPI-CMC at optimum biopolymer ratio had improved surface properties as well as reduced droplet flocculation and coalescence as indicated by increased negative charges and protein surface coverage as well as smaller droplet size. Increased viscosity due to nonadsorbed CMC also contributed to increased stability at high CMC concentration. High Mw CMC was more effective in enhancing surface properties and providing better stability against creaming compared to lower Mw CMC.

    Publications

    • Type: Journal Articles Status: Published Year Published: 2016 Citation: Huan, Y., Zhang, S., & Vardhanabhuti, B.* 2016. Influence of the molecular weight of carboxymethylcellulose on properties and stability of whey protein-stabilized oil-in-water emulsions. Journal of Dairy Science. 99(5): 3305-3315.
    • Type: Journal Articles Status: Published Year Published: 2016 Citation: Huan, Y., Zhang, S., & Vardhanabhuti, B.* 2016. Effect of CMC molecular weight on acid-induced gelation of heated WPI-CMC soluble complex. Journal of Food Science. 81(2):N502.


    Progress 10/01/14 to 09/30/15

    Outputs
    Target Audience:Academic, industry professionals, consumers. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?One M.S. student worked on the project and graduated in April 2015. Two undergraduate students were trained while working on the project. How have the results been disseminated to communities of interest?Results were presented at the American Dairy Science Association Annual Meeting in July 2015. What do you plan to do during the next reporting period to accomplish the goals?Plan is to improve emulsification properties of dairy protein by interaction with anionic polysaccharides.

    Impacts
    What was accomplished under these goals? Heat stable whey protein ingredient was developed by dry-heating with inulin, a non-digestible carbohydrate with known health and technological benefits. Dry-heating conditions were optimized by varying protein and inulin ratios as well as heating conditions.Heat stability was measured by heating 6% w/w protein solutions, pH 6.0 at 85oC for 15 min and the absorbance was measured at 630 nm. Particle size, zeta potential, rheological properties, and lysine content were determined.Improved heat stability was shown by a reduction in turbidity (e.g., 62 to 95 % reduction in A630) and 36 to 74% decrease in particle size without significant change in flow behavior. Maillard reaction was also evident from an increased amount of Amadori compounds and a slight change in color. However, under controlled reaction, the loss of available amino group ranged from 3 to 18% which was considerably low. Improved heat stability of glycated WPI could be explained by increased net negative charge and increased denaturation temperature of WPI. Increased net negative charge can be due to the blockage of lysine, while increased denaturation temperature could be attributed to the alterations of secondary and tertiary structures of WPI.

    Publications

    • Type: Theses/Dissertations Status: Published Year Published: 2014 Citation: O'Chiu, E. 2014. Application of whey protein-polysaccharide complexes in aerated dairy gels. Master thesis, University of Missouri.
    • Type: Journal Articles Status: Awaiting Publication Year Published: 2015 Citation: Wang, Z., Zhang, S., and Vardhanabhuti, B. 2015. Foaming Properties of Whey Protein Isolate and ?-Carrageenan Mixed Systems. J. Food Sci. 85(8): N1893-N1902.
    • Type: Theses/Dissertations Status: Published Year Published: 2015 Citation: He, Y. 2015. Improved heat stability of whey protein isolate by glycation with inulin. Master thesis, University of Missouri.
    • Type: Journal Articles Status: Published Year Published: 2016 Citation: Yan, H., Zhang, S. Effect of CMC Molecular Weight on Acid-Induced Gelation of Heated WPI-CMC Soluble Complex. J Food Sci. 2016 Feb;81(2):N502-7.
    • Type: Conference Papers and Presentations Status: Other Year Published: 2015 Citation: He, Y. and Vardhanabhuti, B. 2015. Improved heat stability of whey protein isolate by glycation with inulin. American Dairy Science Association Annual Meeting, July 2015.


    Progress 10/01/13 to 09/30/14

    Outputs
    Target Audience: We presented at the American Dairy Science Association Annual Meeting in July 2014. Audiences were scientists and representative from the food and dairy industry as well as acadamia. Changes/Problems: Originally, we planned to investigate the effect of ultrasound on improving functional properties of protein. However, we found that after the treatment there was some undesirable aroma. This is why we have changed the plan from ultrasound treatment to dry-heating with inulin. In a separate situation, we found that the shelf-life of milk protein isolate/concentrate was short. The protein ingredients lost their solubility after less than 6 months storage. This led to inconsistant results. We decided not to continue the study on foaming properties of milk protein until we figure out how to improve solubility of the protein. With these challenges and changes, we still proceed with the same overall goal which is to improve functional properties of dairy ingredients. What opportunities for training and professional development has the project provided? There have been one Ph.D. and three Master students working on the projects. We also have undergraduate students volunteering and receiving lab training. How have the results been disseminated to communities of interest? We had three presentations at the American Dairy Science Association Annual Meeting in July 2014. Attendees were scientist and representatives from the food and dairy industry as well as acadamia. What do you plan to do during the next reporting period to accomplish the goals? We will continue to investigate different approaches to improve functional properties of dairy protein ingredients and to determine their digestion properties in the presence of other food components. Our potential plans are: 1. To investigate the effect of drying heating of whey protein with inulin on heat stability of protein. 2. To investigate the effect of fat on digestion properties of mixed dairy protein and polysaccharides. 3. To investigate the potential applications of dairy protein permeate after enzyme hydrolysis.

    Impacts
    What was accomplished under these goals? In improving functional properties of dairy ingredients, the focus of our research has turned to whey protein isolate. By heating whey protein isolate with polysaccharide, heated soluble complexes/particles were formed. These complexes have shown to have improved functional properties in acid-induced gelation and foaming application. One project has identified important factors in complex formation that resulted in improved properties of acid-induced whey protein gel. The results could be applied to improve quality of high protein yogurt. In the second project, we showed that heated whey protein and carrageenan complexes can be used to improve foaming properties of protein especially foam stability. In the last project, heat whey protein-polysaccharide complexes were used to create aerated dairy gel without addition of starch. In a separate goal, we have shown that interactions between dairy protein and polysaccharide can be utilized during digestion. At certain condition, heated whey protein and anionic polysaccharide complexes form intragastric gel during digestion in in-vitro stomach model. The formation of gel implies that the two biopolymers could be used in designing food products with increased satiety or delayed blood glucose response.

    Publications

    • Type: Journal Articles Status: Published Year Published: 2014 Citation: Zhang, S., & Vardhanabhuti, B.* 2014.Acid-induced gelation properties of heated whey protein-pectin soluble complex (Part II): Effect of charge density of pectin. Food Hydrocolloids. 33, 95-103. (published)
    • Type: Journal Articles Status: Published Year Published: 2014 Citation: Zhang, S., Zhang, Z., & Vardhanabhuti, B.* 2014. Effect of charge density of polysaccharides on self-assembled intragastric gelation of whey protein/polysaccharide under simulated gastric conditions. Food Funct., 5, 1829-1838. (published)


    Progress 02/01/13 to 09/30/13

    Outputs
    Target Audience: Research results have reached the target audiences who are members of the food industry and the dairy industry. Efforts relating to lab instructions have reached graduate and undergraduate students. Efforts also reached graduate and undergraduate students during class instructions. Changes/Problems: We have expanded the study to include other functional properties of protein ingredients in order to maximize their utilization and to expand the range of products these ingredients can be applied. These changes do not change the overall goal of the project. What opportunities for training and professional development has the project provided? Training activities: Three graduate students and one undergraduate student have been trained through conducting research, taking courses towards their graduate study, as well as one-on-one discussion with the PI. Professional development: Students presented their research at the Institute of Food Technologists Annual Meeting in July 2013. They also got the chance to discuss their research with food indusrty members. How have the results been disseminated to communities of interest? Research results have been presented at the Institute of Food Technologists Annual Meeting in July 2013. Research results have also been published in peer-reviewed journals. What do you plan to do during the next reporting period to accomplish the goals? Graduate and undergraduate students will be trained to conduct research to optimize the functional properties of dairy protein ingredients in food products including bakery products, fermented dairy product, and pasta products. Students will present their research at the scientific meeting as well as publish their results in peer-reviewed journals.

    Impacts
    What was accomplished under these goals? Impact Change in knowledge: New fundamental information has been generated to better understand foaming properties of milk proteins and factors affecting their interactions with polysaccharides. Change in actions: By optimizing foaming properties and gelation properties, the food industry can increase the use of dairy protein ingredients in food products. Change in conditions: Three graduate students and one undergraduate student have been trained. These scientists would be trained to be future leaders in the area of food science. This research could lead to an increase use of dairy protein ingredients in foods/beverages which will also improve nutritional qualities of the products. Accomplishments against each objective. Objective 1: Determine factors affecting foaming properties of MPC. These include protein concentration, pH, salt type and concentration, temperature, and other solutes. Activity 1: Foaming properties of milk protein concentrate. The goal of this study was to investigate the effects of calcium and sodium citrate (chelator) on foaming properties of milk protein concentrate (MPC). Calcium chloride and/or sodium citrate were mixed with MPC solutions and pH was adjusted such that the final solutions contained 5% w/w protein, 0-20 mM CaCl2 and 0-40 mM citrate at pH 7.0. Foam was generated by whipping MPC solutions in a KitchenAid mixer. Foaming properties were determined by measuring overrun and drainage ½ life. Physical properties of pre-foam solutions, including solubility, turbidity, and particle size were measured. Foam rheology was determined using a controlled- strain and rate rheometer. Foaming quality was also tested in angle food cake. Results showed that addition of 20 mM CaCl2 caused a reduction in overrun (P < 0.05) but no significant effect on foam stability. Either with or without of CaCl2, increasing citrate concentration significantly increased the overrun (P < 0.05) and drainage ½ life of MPC foams. However, samples having higher citrate concentration (40 mM) only showed improvement in overrun but a decrease in drainage ½ life. Enhanced overrun corresponded to a reduction in particle size and turbidity and an increase in solubility of pre-foam solutions. Interestingly, interfacial rheology revealed that pre-foam solutions with CaCl2 exhibited higher interfacial viscosity and interfacial elastic modulus, while the presence of citrate reduced interfacial viscosity and interfacial elastic modulus. These results indicated that appropriate concentrations and combination of salts are needed to optimize foaming properties of MPC. Activity 2: We have expanded the study to include foaming properties of whey protein. Three WPI and λC systems were prepared: 1) heated WPI and λC soluble complex (h-CPX), (2) heated WPI with added λC (pWPI+λC), and (3) unheated WPI with λC. All systems had 5 % (w/w) protein and 0, 0.005, or 0.025% (w/w) λC at pH 7. Foam was generated by beating the solution using a KitchenAid mixer. Foaming ability and foam stability were determined by measuring the overrun and drainage 1/5 life, respectively. Foam rheological properties were determined using a Kinexus Pro Rheometer, while foam microstructure was visualized by confocal laser scanning microscopy (CLSM). Both h-CPX and pWPI+λC foams showed improved overrun and stability (P < 0.05) compared to unheated WPI at similar λC concentrations. At 0.025% λC, h-CPX foams were significantly more stable (drainage 1/5 life = 135±10 min) compared to pWPI+λC foams (112±3 min). Foam rheology results showed that both h-CPX and pWPI+λC foams were more elastic than unheated WPI foams. CLSM analysis revealed that h-CPX foams were composed of smaller bubbles and showed slower rate of disproportionation compared to pWPI+λC foams, corresponding to foam stability results. Results suggest that, at optimum conditions, heated WPI-λC soluble complex have significantly enhanced foaming properties. This can be applied to various dairy-based foams as well as new product development. Activity 3: We have expanded the study to include gelation properties of whey protein. Heated WPI/pectin complex solutions (5% w/w protein and 0 – 0.1 pectin to WPI weight ratios) were formed by heating the mixtures at pH 7.0. Glucono-δ-lactone was added to induce gelation. For comparison, WPI and pectin were heated separately and then mixed together before gelation. (WPI aggregates/pectin gels). Gel characterizations included texture analysis, water holding capacity (WHC) measurement, and confocal laser scanning microscopy (CLSM) analysis. Heating WPI with pectin led to larger particles compared to heated WPI with added pectin, indicating the formation of complex or different type of aggregates. All gels formed from heated WPI/pectin soluble complex (complex gels) showed significant improvement in WHC compared to WPI aggregates/pectin gels (p < 0.05). Charge density of pectin played a dominant role in gel strength. Complex gels from highly charged pectin were stronger than WPI aggregates/pectin gels at all biopolymer ratios, with the most remarkable improvement (43% stronger) at 0.05 biopolymer ratio. CLSM analysis revealed that complex gels had smoother gel network with less phase separation. The study demonstrates the benefits of heated WPI/pectin soluble complex in enhancing the properties of acid-induced WPI gels. This can be applied to improve the quality of yogurt or to develop new shelf-stable gel-based products.

    Publications

    • Type: Journal Articles Status: Published Year Published: 2014 Citation: Zhang, S., Hsieh, F. H., & Vardhanabhuti, B. (2014). Acid-induced gelation properties of heated whey proteinpectin soluble complex (Part I): Effect of initial pH. Food Hydrocolloids, 36, 76-84.
    • Type: Journal Articles Status: Published Year Published: 2014 Citation: Zhang, S., & Vardhanabhuti, B. (2014). Effect of initial protein concentration and pH on in vitro gastric digestion of heated whey proteins. Food chemistry, 145, 473-480.
    • Type: Theses/Dissertations Status: Awaiting Publication Year Published: 2014 Citation: Zhengshan Wang. FOAMING PROPERTIES OF WHEY PROTEIN ISOLATE AND LAMBDA CARRAGEENAN MIXED SYSTEMS. Master thesis, University of Missouri.
    • Type: Theses/Dissertations Status: Awaiting Publication Year Published: 2014 Citation: Yan Huan. APPLICATION OF SOLUBLE WHEY PROTEIN-CARBOXYMETHYLCELLULOSE COMPLEX IN EMULSION AND ACID-INDUCED GELATION. Master thesis, University of Missouri.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Wang, Z. and Vardhanabhuti, B. Foaming Properties of Whey Protein Isolate and lambda-Carrageenan Mixed Systems. Institute of Food Technologists Annual Meeting, July 2013, Chicago, IL.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Yan, H. and Vardhanabhuti, B. Acid-induced gelation of heated soluble whey protein isolate and CMC particles. Institute of Food Technologists Annual Meeting, July 2013, Chicago, IL.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Zhang, S. and Vardhanabhuti, B. Improved Acid-induced Gelation Properties of Whey Protein by Heated Whey Protein/Pectin Soluble Complex. Institute of Food Technologists Annual Meeting, July 2013, Chicago, IL.