Progress 10/01/10 to 09/30/13
Outputs
Target Audience: The target audience is owners of small vineyards and wineries, researchers and students in food and nutritional sciences, consumers, particularly underserved populations who are searching for affordable health promoting foods. Three internship opportunities for undergraduate students in 2012 and 2013 summer; presentation in Family and Consumer Sciences Department graduate seminar course; presentation in the seminar series of School of Agricultural and Environmental Sciences, North Carolina A&T State University. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Six undergraduate students, one graduate student and two lab technicians were financially supported and technically trained through this project. Each of them is now able to complete a task independently. How have the results been disseminated to communities of interest? The results were shared with vineyard/winery owners that collaborated with PI, presented in the seminar series organized by the School of Agricultural and Environmental Sciences and graduate seminar course in Family and Consumer Sciences Department, and presented in different conferences. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
From 10/01/2010-09/31/2011, the proximate composition, fiber content and polyphenol composition of skin, seeds and stems of the dry Muscadine Nobel and Cabernet Sauvignon pomace from NC winery were determined, and the effects of drying methods on the changes of total polyphenol (TP), total anthocyanin(TA) and total flavonoids (TF) were evaluated. Objectives 1 and 2 were met. Results show that grape pomace (GP) was rich in dietary fiber and polyphenol but lower in protein content. Grape seeds contained 10-14% oil that is rich in polyphenol and unsaturated fatty acids. Over 50% of GP dry weight was insoluble dietary fiber. Therefore, grape pomace has potential to serve as a source of dietary fiber rich in polyphenols for functional food development. Depending on the purpose of application, whole pomace or a specific part of pomace may be used. From 10/01/2011-09/31/2012, protein-polyphenol interaction, protective effects of food proteins on polyphenols, and the feasibility of grape pomace in bread making were studied. Objective 3 and part of objective 5 were met. Results: Dehydration of GP at room temperature for one week and at 70C in vacuum oven resulted in significant loss of polyphenols in skins of GP compared to freeze dry. Some food showed protective effects on extracted GP polyphenols, this may increase the stability of those polyphenols during thermal processing of foods. GP also showed great feasibility and potential to serve as a functional food ingredient in bread making to deliver health promoting polyphenols and dietary fiber to consumers. The development of functional food products using GP will add value to this agricultural by-product and will finally benefit grape farmers. From 10/01/2012-09/31/2013, the effects of GP polyphenol extract (GPPE) on the in vitro digestibility of macronutrients was studied and the safety of consuming GP was studied using young rat model. Findings: GPPE significantly reduced the digestibility of starch and lipid without obvious impact on the in vitro digestion of protein. Substituting up to 30% of starch in the diet with GP did not impact the growth performance of young rats, but improved the blood lipid profile. Expressions of genes responsible for the fatty acid synthesis and lipid hydrolysis/metabolism in liver were moderately down regulated by GP diet. Therefore, GP has anti-obesity properties.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Jianmei Yu and Mohamed Ahmedna (2013). Functional Components of Grape Pomace: Their Compositions, Biological Properties and Potential Applications (an invited review). International Journal of Food Science and Technology, 48 (2): 221-237.
- Type:
Book Chapters
Status:
Published
Year Published:
2013
Citation:
Jianmei Yu and Ivy Smith. Thermal stability of major classes of polyphenols in skins, seeds and stems of grape pomace. 2013. In book Grapes, Production, Phenolic Composition and Potential Biomedical Effects . Nova Science Publishers, Inc.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2012
Citation:
Ji S, Luo Z and Yu J. Impacts of food proteins on the thermal stability of polyphenols extracted from Muscadine grape pomace. ACS Southeast Regional Meeting, November 14-17, 2012, Raleigh, NC.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Yu J and Smith I. Comparison of Fatty Acid Composition and Antioxidant Contents of Grape Seed Oils from Some Grape Cultivars Grown in North Carolina. The 17th ARD symposium, April 6-10, 2013, Jacksonville, FL.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
McMillan A, Smith I, Lucas D and Yu J. Dietary Fiber and Polyphenol Composition of Grape Pomaces from Four Grape Cultivars Grown in North Carolina. The 17th ARD symposium, April 6-10, 2013, Jacksonville, FL.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Smith I, McMillan A, Lucas D and Yu J. Fortification of wheat bread with grape pomace for promotional health benefits from polyphenols and dietary fiber. IFT Annual Meeting, July 13-16, 2013, Chicago, IL.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Yu J and Ji S. In vitro Evaluation of Grape Pomace Extract on the Digestibility of Macronutrients. IFT Annual Meeting, July 13-16, 2013, Chicago, IL.
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Progress 01/01/12 to 12/31/12
Outputs
OUTPUTS: Objectives to be addressed during this reporting period are to evaluate the impacts of the interaction between grape pomace (GP) polyphenols and major food ingredients on the heat stability of Muscadine polyphenols because heat stability of polyphenols determines their bioavailability and bioactivities in processed food, and to develop functional food products using grape pomace. Data from these objectives will guide product formulation and provide information about the consumer preferences for bread modified with GP. Interactions between food proteins and polyphenol and their protective effects on the thermal stability of grape pomace polyphenols were studied using casein, a whey protein isolate, a soy protein isolate, and egg white protein. Results indicate that some food proteins interacted with grape polyphenol to form a precipitate. The strongest interaction occurred with egg white protein, followed by soy protein and whey protein. The degree of protection is in the order of casein>egg white protein>soy protein. Whey protein isolates did not show a protective effect on total anthocyanins. In the case of flavonoids, proteins form significant amount of insoluble complexes with GP polyphenols before heating. Concentrations of total anthocyanin and total flavonoid of the Muscadine Nobel pomace extract were determined and properly diluted with right before use. Polyphenol extracts from GP were quantitatively mixed with protein solutions (1% protein in phosphate buffer) in screw capped test tubes and heated in a water bath for different times (0, 30, 60, 90, 120 and 150 minutes) at different temperatures (50, 70 and 90 degrees Celsius). Samples were immediately cooled to room temperature and centrifuged. Concentrations of total polyphenol (TP), total anthocyanin (TA) and total flavonids (TF) in clear supernatants were determined and compared with those without proteins. Application of grape pomace in bread could add nutritional value. In this study grape pomace from the 4 grape cultivars were used to fortify white bread. A standard white bread formula was modified by replacing 5 and 10% of white flour with GP. Bread with 0% GP was used as a control. Reformulated dough was baked following a standard bread making procedure. Consumer preferences of breads containing different type and quantity of GPs were evaluated with a sensory panel of 15 untrained individuals. Incorporation of grape pomace (GP) in bread could add nutritional value to a widely consumed product. This study shows that bread containing 5% GP had a loaf volume and texture similar to the control, but bread with 10% GP became denser and harder, regardless of grape cultivars used. Total dietary fiber, polyphenol content and antioxidant activity of the bread increased with increasing GP content in the formula. The cultivar of grape, but not the level of GP inclusion, had significant effects on consumer preferences of aroma, flavor and texture of the (P<0.05). The preference for bread color was not influenced by either the cultivar or the level of GP inclusion (P<0.05). Overall, the consumer acceptability of the GP fortified breads were similar to that of white bread (P<0.05). PARTICIPANTS: Individuals who worked on the project include project team members and students were: Dr. Jianmei Yu, Department of Family and Consumer Sciences, North Carolina Agricultural and Technical State University Dr. Tracy Hanner, Department of Animal Science, North Carolina Agricultural and Technical State University Zhenglin Luo, Lab Technician, Department of Family and Consumer Sciences, North Carolina Agricultural and Technical State University Graduate Student: Ivy Smith Undergraduate students: Ashley McMIllan and Shuang Ji TARGET AUDIENCES: Academic researchers Graduate and undergraduate students Food industry Grape and wine producers PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
This study shows that some food proteins can be used as carrier and protector of grape pomace (GP) polyphenols during functional food development and thermal processing. Results obtained during this project period indicates that some food proteins have protective effects on polyphenols such as anthocyanins extracted from grape pomace thus increasing the stability of those polyphenols during food processing such as baking and other thermal processing. Grape pomace also showed great feasibility and potential to serve as a functional food ingredient in bread making to deliver health promoting polyphenols and dietary fiber to the product and consumer. Overall, the consumer acceptability of the GP fortified breads were similar to that of white bread. The development of functional food products using grape pomace adds value to this agricultural by-product, and will ultimately benefit grape farmers in North Carolina and elsewhere.
Publications
- Ji, S., Luo, Z. and Yu, J. (2012). Impacts of food proteins on the thermal stability of polyphenols extracted from muscadine grape pomace. ACS Southeast Regional Meeting, Abstract # SERM313. November 14-17, 2012, Raleigh, NC.
- McMillan, A., Smith, I., and Yu, J. (2012).Comparison of dietary fiber and polyphenol composition of grape pomaces from four grape cultivars grown in North Carolina. ACS Southeast Regional Meeting, Abstract: SERM1162. November 14-17, 2012, Raleigh, NC.
- Smith, I., Luo, Z. and Yu, J. (2012). Heat stability of polyphenols extracted from grape pomace at different pH. 2012 IFT Annual Meeting, paper #: 193-89, June 25-28, 2012, Las Vegas Nevada.
- Yu, J., McMillan, A., & Tyson. L. (2012). Solubility and digestibility characterization of dietary fiber in grape pomace. 2012 IFT Annual Meeting, paper #:279-21, June 25-28, 2012, Las Vegas Nevada. June 25-28, 2012, Las Vegas Nevada.
- Smith, I., & Yu J. (2012). Fortification of White Bread with Grape Pomace from North Carolina Wineries. FSU Student research Conference, April 14-15, 2012, Fayetteville, NC.
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Progress 01/01/11 to 12/31/11
Outputs
OUTPUTS: During the period of October 1-September 31, 2011, our research team has worked on the following objectives: 1) to characterize the proximate composition and phenolic composition of Muscadine Nobel and Cabernet Sauvignon pomace from NC wineries, 2) to investigate the stability of bioactive polyphenols from muscadine pomace. Fermented grape pomaces (GP) were obtained from two North Carolina (NC) wineries, dried by freeze drying and vacuum drying methods and separated into seeds, skins and stems. The proximate composition, fiber content and polyphenol composition of each part of the dry GP were determined, and the effects of drying methods on the changes of total polyphenol (TP), total anthocyanin(TA) and total flavonoids (TF) were evaluated. The research findings were shared with two North Carolina wineries that provided grape pomace for this research project, presented in seminar series hosted by the Agricultural Research of the School of Agricultural and Environmental Sciences, and Faculty Research Appreciation Day hosted by the Division of Research, NC A&T State University. These findings were also presented in the ARD 16th Biennial Research Symposium in April 9-13, 2011 in Atlanta, Georgia and 2011 IFT Annual Meeting June 11-14, 2011, New Orleans, Louisiana. PARTICIPANTS: The project is led by Dr. J. Yu (principal investigator). She is responsible for project coordination, experimental design, writing annual report and final report, and advice/supervision of Research Associate and students. The PI has been collaborated with two NC winery owners Andy Zeman and Max Lloyd. They provided free grape pomace for this project, and they also supported me to obtain a capacity building grant. Their contact information is showing below. Andy Zeman, Owner of Benjamin Vineyard and Winery, 6516 Whitney Road, Graham, NC 27253, Phone: (336) 376-1080, email: benjaminwines@cs.com. Max Lloyd, Owner of Grove Winery, 7360 Brooks Bridge Rd., Gibsonville, NC 27249, Winery: (336) 584-4060, Email: info@grovewinery.com. The project supported one graduate and two undergraduate students since previous reported. Graduate student Lori Tyson was trained to use high performance Liquid Chromatography (HPLC) system to separate individual polyphenols in grape pomace extracts during summer term. Undergraduate students Ivy Smith and Ashley McMillan were trained with techniques for polyphenol extraction, purification, determination of total polyphenols, total anthocyanins and total flavonoids. They are also trained to conduct heat treatment of grape pomace extract under different experimental conditions, and to evaluate the effects of pH, temperature and heating time on the loss of different classes of polyphenols. Ivy Smith is accepted as an Under Graduate Research Scholar and she will present the research results in 2012 IFT Annual Meeting. Co-PI Dr. Tracy Hanner Dr. Hanner (department of animal science) will assist the PI with animal trials for the safety evaluation of the grape pomace and Dr Joshua Idassi in Cooperative Extension will assist PI to dissemination of research result among NC wineries and low income population through presentation in the Small Farmer's Week events and through county extension agents. TARGET AUDIENCES: Target audiences of our researching findings include the owners of wineries, people who are interested in healthy diet, food companies that are interested in developing functional foods, and scientific communities. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
North Carolina wineries produce significant amount of grape pomace. This study is providing new knowledge about the nutritional content of grape pomace from two North Carolina wine grapes, with the aim of developing more healthful high fiber foods to improve health and curb obesity, while also establishing a value-added use for this underutilized byproduct. New knowledge was also generated which suggests some directions for processing this product for use in functional foods, or animal feeds. New knowledge is the result of the research activities conducted during this period, as outlined below: Proximate composition of GP: Ash, protein and crude fat contents of different parts of pomace were identified. These studies suggest that GP skins have potential to be used as an ingredient to provide minerals, while seeds have greater potential to be used to produce food oil rich in polyphenols and unsaturated fatty acids. Polyphenol composition of GP: These results show that GP is rich in polyphenols, but the polyphenol composition of GP is variety dependent and differs from skins to seeds. Depending on the purpose of application, whole pomace or a specific part of pomace may be used. Solubility and digestibility of GP fiber: The total dietary fiber (TDF), soluble dietary fiber (SDF), and insoluble dietary fiber (IDF) contents in GPs of the three grape varieties were determined to provide better understanding the health benefit of GP fibers. It was found that the solubility and digestibility of GP fiber depend on the variety of grape. GP has potential to serve as a source of dietary fiber for functional food development, but the amount of GP to be incorporated needs to be carefully monitored because of the high lignin content in seeds. Effects of drying methods on polyphenol composition of GP: Compared to freeze drying, vacuum oven drying resulted in significant loss of total polyphenols, total anthocyanin and total flavonoids in each part of GP. The largest loss was total anthocyanins observed for in the muscadine skin. Therefore, to preserve the bioactive components in the grape pomace due to heat damage, a mild drying method is required. The monetary resources ensured we were able to 1) have sufficient supplies to conduct experiments, 2) support two student research assistants per semester, 3) repair equipment, and 4) support activities for disseminating the research findings and build collaborative relationship with wineries.
Publications
- No publications reported this period
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Progress 01/01/10 to 12/31/10
Outputs
OUTPUTS: This project is exploring a new approach to use Muscadine pomace as an ingredient to develop functional food products with an affordable price, enhanced antioxidant content and health promoting properties for underserved population. The health promoting properties of the bioactive compounds in food products are influenced by their stability and their effects on the sensory properties of the products. Therefore, the specific objectives of this project are: 1) to characterize the proximate composition and phenolic composition of Muscadine pomace from NC wineries, 2) to investigate the stability of bioactive polyphenols from Muscadine pomace, 3) to evaluate the interaction between polyphenols from grape pomace and major food ingredients and their impacts on the heat and pH stability of Muscadine polyphenols, 4) to evaluate the safety of grape pomace and the effects of polyphenol-ingredient interactions on the bioavailability of polyphenols and digestibility of major food components, and 5) to develop functional food products such as bread and meatballs using Muscadine pomace, and evaluate the impacts of Muscadine pomace on Physico-chemical properties, sensory quality, and consumer acceptance of the final product. We hypothesize that the stability of polyphenols is temperature and pH dependent, and is affected by light and exposure time but the interaction of grape pomace polyphenols with major food components may have a protective effect on polyphenols. Grape pomace (GP) can be included in certain food products such as bread and meatballs at up to 5% without causing significant antinutritional effects or affecting consumer acceptance. A 3x4 factorial experimental design will be used to evaluate the effects of temperature, heating time and pH on the stability of GP polyphenols with and without light. The interactions between major GP polyphenols and major components in ingredients used for baking, including starch, gluten, leavening, egg white, milk casein, whey protein, salt and sugar, will be investigated at a given GP extract concentration and various concentrations of other components. The effects of interaction on the stability of polyphenols will be evaluated by kinetic determination of thermal degradation rate constants of GP polyphenols in the presence and absence of these food components. The antinutritional effect of GP at level 2-10% in the diet will be evaluated using a rat model and using in vitro digestive enzyme inhibition model. Bread and meatballs will be used as a food model to investigate the consumer acceptability of the product developed from GP. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Upon the completion of this project, we will gain new knowledge about the stability of grape pomace polyphenols under different processing conditions such as drying, baking and cooking; the effects of polyphenol-ingredient interactions on the stability and availability of grape pomace polyphenols, the safety of using grape pomace as a food ingredient, and the consumer acceptance of food products containing grape pomace. The success of this project will help toward producing a new, more environmentally friendly and cost efficient value-added product from a bioactively rich agricultural by-product. It will give the grape and wine industry a value-added product. More people, particularly, low income populations and people whose diets are lower in health promoting polyphenols will be able to access the health benefits of Muscadine polyphenols through regular consumption of bread and meatballs. The health status of end users of newly developed food products from this research may be improved by the intake of muscadine pomace fortified food products.
Publications
- No publications reported this period
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