Progress 02/15/05 to 02/14/09
Outputs
OUTPUTS: Berry fruit contain an abundance of polyphenolics, and have been shown to have a variety of health-promoting properties. Berries are available fresh, but also are distributed and consumed frozen as well as in various thermally processed (juices, canned, pureed) forms. Additionally, many of the processed products may be stored for extended periods prior to consumption. Unfortunately, little information is available regarding the effects of processing and storage on the composition and content of berry polyphenolics. Information is also lacking on the absorption/metabolism of berry polyphenolics and health effects of the berry products. Fresh blackberries, blueberries, and black raspberries were processed into various forms (individually quick frozen, canned-in-water, canned-in-syrup, pureed, clarified and non-clarified juices) and evaluated for polyphenolic composition (anthocyanins, procyanidins, ellagitannins) and content, antioxidant capacity and percent polymeric color immediately following processing and after 1, 3, and 6 months of storage at room temperature. Animal models were used to study absorption and metabolism of polyphenolics in processed berry products. PARTICIPANTS: The principal co-investigators on this grant are Dr. Luke Howard and Dr. Ronald Prior, who facilitate collaboration between the Department of Food Science at the University of Arkansas-Fayetteville and the Arkansas Children's Nutrition Center-Little Rock. They are assisted by graduate research assistants, Tiffany Hager (Ph.D. candidate) and Aaron Hager (M.S. candidate), and research associate II, Cindi Brownmiller. Dr. Howard has coordinated the work involving processing effects on berry polyphenolics, with Mr. Hager working on black raspberries, Ms. Hager working on blackberries, and Ms. Brownmiller working on blueberries. Dr. Prior has coordinated the work involving bioavailability of polyphenolics from processed berry fractions, with Ms. Hager working on blackberries, blueberries, and black raspberries, and Mr, Hager working on black raspberries and blueberries. TARGET AUDIENCES: Results of this project are of interest to fruit processors, nutritionists, and scientists working in the field of polyphenolic chemistry. Research findings have been presented at the 7th International Phytochemical Conference, the 2007 Berry Health Benefits Symposium, the Institute of Food Technologists annual meetings (2006, 2007, and 2008), the 2008 American Chemical Society national meeting, and Experimental Biology 2009. Presentations will also be made at the 2009 Berry Health Benefits Symposium in June. PROJECT MODIFICATIONS: None
Impacts
Individually quick frozen berries retained comparable levels of polyphenolics and antioxidant capacity as fresh berries over 6 mo storage indicating that they are an excellent source of antioxidant-rich polyphenolics. All thermal processing methods (canning, juicing, and pureeing) resulted in significant losses of polyphenolics and antioxidant capacity with the greatest losses occurring in juices, where appreciable levels of polyphenolics (anthocyanins in all berries, procyanidins in blueberries, and ellagitannins in blackberries and black raspberries) were retained in the waste material. Future studies should focus on the development of methods to recover and utilize polyphenolics from waste materials. Significant losses of anthocyanins occurred in all processed berry products over 6 mo storage, and these losses were accompanied by increased polymeric color values. Extensive losses of procyanidins occurred during storage of processed blueberry products, whereas ellagitannins in blackberries and black raspberries and flavonols in all berries were well retained. The antioxidant capacity of processed products remained relatively stable during storage despite significant losses of anthocyanins, suggesting that polymeric pigments formed during storage have comparable free radical scavenging capacity as anthocyanins. Additional research is needed to identify and determine the bioavailability of polymeric pigments that form in processed berries during storage. Our results indicate that processed berries, excluding frozen, have much lower levels of polyphenolics and antioxidant capacity than fresh berries. Absorption of antioxidant components in processed products from blackberries (juice, presscake, puree and whole berries) was studied in the weanling pig animal model. Feeding the pureed fruit, but not clarified juice, was the most effective at elevating plasma antioxidant capacity (AOC) at all time points up to 8 h. Feeding blackberry presscake and frozen whole fruit increased plasma AOC only at 8 h after the meal which suggests that the antioxidants were not absorbed until they reached the colon and metabolites produced by microflora were absorbed that may have been responsible for the increase in AOC. 3,4-dihydroxybenzoic and 3-hydroxybenzoic acids were major phenolic acids which appeared in the gastrointestinal tract following a meal of black raspberries. Effects of processing may explain our finding that feeding blueberry juice or purified anthocyanins (ACNs) from blueberry prevented obesity in a mouse model, but feeding the whole berry as a freeze dried powder was ineffective. ACNs may be more readily absorbed in the stomach and small intestine when present in solution compared to the whole berry powder. Decreased absorption in the upper GI tract results in more ACNs reaching the cecum and colon and being absorbed as phenolic acid metabolites. This may have benefit in terms of overall AOC but not in terms of preventing obesity. More research is needed to characterize and determine the bioavailability of ACN polymers formed during storage of processed berries and to determine interactions of berry components and the development of obesity.
Publications
- Prior, R.L., Wu, X., Gu, L., Hager, T., Hager, A., Wilkes, S. and Howard, L. 2009. Purified berry anthocyanins but not whole berries normalize lipid parameters in mice fed an obesogenic high fat diet. Molec. Nutr. Food Res. (accepted)
- Brownmiller, C., Howard, L. R. and Prior, R. L. 2009. Processing and storage effects on procyanidin composition and concentration of processed blueberry products. J. Agric. Food Chem. 57:1896-1902.
- Howard, L.R., Brownmiller, C.R. and Prior, R. L. 2009. Processing and storage effects on blueberry (Vaccinium corymbosum L.) polyphenolics. Acta Hort (In-press).
- Wu, X., Pittman III, H.E., Hager, T., Hager, A, Howard, L. and Prior, R.L. 2009. Phenolic acids in black raspberry and in the gastrointestinal tract of pigs fed black raspberry. Molec. Nutr. Food Res. 53: (In-press)
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Progress 02/15/08 to 02/14/09
Outputs
OUTPUTS: Berry fruit have been shown to have a variety of health-promoting properties. Berries are available fresh, but also are distributed as frozen and in various processed (juices, canned, pureed) forms, and may be stored for extended periods prior to consumption. Unfortunately, little information is available regarding the effects of processing and storage on the absorption/metabolism of berry phenolics and health effects of the berry products. Animal models have been used to study absorption and metabolism of phytochemicals in processed berry products. PARTICIPANTS: The principal co-investigators on this grant are Dr. Luke Howard and Dr. Ronald Prior, who facilitate collaboration between the Department of Food Science at the University of Arkansas-Fayetteville and the Arkansas Children's Nutrition Center-Little Rock. They are assisted by graduate research assistants, Tiffany Hager (Ph.D. candidate) and Aaron Hager (M.S. candidate), and research associate II, Cindi Brownmiller. Dr. Howard has coordinated the work involving processing effects on berry phytochemicals, with Mr. Hager working on black raspberries, Ms. Hager working on blackberries, and Ms. Brownmiller working on blueberries. Dr. Prior has coordinated the work involving bioavailability of polyphenolics from processed berry fractions, with Ms. Hager working on blackberries. TARGET AUDIENCES: Results of this project are of interest to fruit processors, nutritionists, and scientists working in the field of polyphenolic chemistry. Research findings have been presented at the 7th International Phytochemical Conference, the 2007 Berry Health Benefits Symposium, the Institute of Food Technologists annual meeting, and the American Chemical Society national meeting. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The absorption of antioxidant components in processed products from blackberry (juice, presscake, puree and whole berries) was studied in the weanling pig animal model. Blackberry products were homogenized with water and administered to 5 pigs (7-12 kg) via intragastric intubation at a standardized anthocyanin (ACY) concentration of 25.9+2.2 mg ACYs/kg body weight (BW) or 57.7+5.0 micromoles ACYs/kg BW. Blood samples were collected at 0, 0.5, 1, 2, 4, and 8 hr after the meal and plasma antioxidant capacity was measured. Feeding the pureed fruit was the most effective at elevating plasma antioxidant status at all time points compared to 0 h AOC, despite the same anthocyanin concentration for all samples. Feeding blackberry presscake and frozen fruit increased plasma AOC only at 8 h which suggests that the antioxidants were not absorbed until they reached the colon and absorption of metabolites produced by colonic microflora may have been responsible for the increase in AOC. Consumption of clarified juice did not significantly alter plasma AOC at any time point. The response in plasma AOC was affected by the extent of processing (i.e. thermal treatment and exclusion of seeds and pulp), suggesting that processing may affect the bioavailability of anthocyanins or other polyphenolics that are the typical sources of antioxidant capacity. There was significant metabolism of the native anthocyanins and the extent of metabolism (methylation and glucuronidation) appeared to be relatively consistent in all processed products with the possibility of enhanced glucuronidation after processing. This suggests that the processing does not appreciably affect the metabolism of the anthocyanins, despite some possible effects on bioavailability. More research is needed to characterize and determine the bioavailability of anthocyanin polymers formed during storage of processed berries. Purified anthocyanins from blueberry were shown to prevent obesity in a mouse model of obesity, but the whole berry fed as a freeze dried powder was not effective. However, blueberry juice fed in place of drinking water retained some of the anti-obesity effects. More studies are needed to determine interactions of components in blueberries that have opposing effects on the development of obesity.
Publications
- Prior, R.L., Wu, X., Gu, L., Hager, T.J., Hager, A., Howard, L.R. 2008. Whole Berries Versus Berry Anthocyanins: Interactions with Dietary Fat Levels in the C57BL/6J Mouse Model of Obesity. J Agric Food Chem. 56(3):647-53.
- Hager, A., Howard, L.R., Prior, R L., Brownmiller, C. 2008. Processing and Storage Effects on Monomeric Anthocyanins, Percent Polymeric Color and Antioxidant Capacity of Processed Black Raspberry Products. 73:H134-H140.
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Progress 02/15/07 to 02/14/08
Outputs
OUTPUTS: Berry fruit have received much attention due a variety of health-promoting properties associated with polyphenolics contained within the fruit. Berries are not only available fresh, but are widely distributed as frozen and thermally processed (juices, canned, pureed) forms, and stored for extended periods prior to consumption. Unfortunately, limited information is available regarding the effects of processing and storage on berry polyphenolics. In this study the effects of processing and six months storage at room temperature on the polyphenolic content of individually quick frozen (IQF), canned in water, canned in syrup, purred and juiced products of blueberries, blackberries and black raspberries were evaluated. Anthocyanins, flavonols, procyanidins, and ellagitannins were evaluated by HPLC. The oxygen radical absorbing capacity (ORAC) and percent polymeric color values of the samples were also evaluated. The research findings were presented at the 2007 Berry Health
Benefits Symposium and the Institute of Food Technologists annual meeting.
PARTICIPANTS: The principal co-investigators on this grant are Dr. Luke Howard and Dr. Ronald Prior, who facilitate collaboration between the Department of Food Science at the University of Arkansas-Fayetteville and the Arkansas Children's Nutrition Center-Little Rock. They are assisted by graduate research assistants, Tiffany Hager (Ph.D. candidate) and Aaron Hager (M.S. candidate), and research associate II, Cindi Brownmiller. Dr. Howard has coordinated the work involving processing effects on berry phytochemicals, with Mr. Hager working on black raspberries, Ms. Hager working on blackberries, and Ms. Brownmiller working on blueberries. Dr. Prior has coordinated the work involving bioavailability of polyphenolics from processed berry fractions, with Ms. Hager working on blackberries.
TARGET AUDIENCES: Results of this project are of interest to fruit processors, nutritionists, and scientists working in the field of polyphenolic chemistry. Dr. Howard gave two seminars on processing effects on berry polyphenolics at national conferences, and one seminar at an international conference and Dr. Prior gave one seminar on bioavailability of berry polyphenolics at a national conference, and one seminar at an international conference. Research results were also presented in poster sessions at the Institute of Food Technologists Annual Meeting in Chicago, IL.
PROJECT MODIFICATIONS: Due to difficulty in hiring personnel to conduct animal feeding trials at the Arkansas Children's Nutrition Center, we have requested a one year no cost extension to finalize the project.
Impacts
Methods are needed to prevent polyphenolic losses during processing and storage, especially in juices where appreciable levels of the compounds are retained in waste materials. Future studies should focus on the development of methods to recover polyphenolics from waste materials. The recovered compounds could be added back to juices or be used as nutraceutical ingredients. In canned products significant quantities of polyphenolics diffused out of the berries into the liquid canning medium, indicating that methods are needed to prevent or ameliorate leaching of polyphenolics. More research is needed to characterize and determine the bioavailability of anthocyanin polymers formed during storage of processed berries. Our results indicate that processed berries, excluding frozen, have much lower levels of polyphenolics and antioxidant capacity than fresh fruit.
Publications
- Brownmiller, C, Howard, L. and Prior, R.L. 2007. Processing and storage effects on blueberry anthocyanins and polymeric color. Abstract 146-01. IFT Annual Meeting, Chicago, IL. July.
- Hager, A., Howard, L. and Prior, R.L. 2007. Changes in anthocyanins and antioxidant capacity in processed black raspberry products during storage. Abstract 146-04. IFT Annual Meeting, Chicago, IL. July.
- Hager, T., Howard, L. and Prior, R.L. 2007. Changes in monomeric anthocyanins, polymeric color, and antioxidant capacity in processed blackberry products during storage. Abstract 211-01. IFT Annual Meeting, Chicago, IL. July.
- Hager, A.C. 2007. Processing and storage effects on black raspberry polyphenolics and antioxidant capacity. MS. Thesis. University of Arkansas.
- Hager, T.J. 2007. Processing effects on the antioxidant capacity, polyphenolic content, absorption and metabolism of apache blackberries. Ph.D. Dissertation. University of Arkansas.
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Progress 02/15/06 to 02/15/07
Outputs
Fresh blackberries, black raspberries, and blueberries are an excellent source of polyphenolics and antioxidant capacity, but information is lacking on how different processing methods and storage influence their polyphenolic content. In this study we measured changes in polyphenolics and antioxidant capacity in various processed products over 6 mo storage. Blackberries (cv. Apache), black raspberries (cv. Munger), and blueberries (cv. Bluecrop) were evaluated as fresh, individually quick frozen (IQF), canned in water, canned in syrup, puree, and clarified and non-clarified juices. Processed samples stored for 1 day, and 1, 3, and 6 months were evaluated by HPLC for anthocyanin, flavonol, and ellagitannin content, antioxidant capacity by the oxygen radical absorbing capacity (ORAC) and photochemiluminescence (PCL) assays, and polymeric color by a colorimetric assay. In blackberries monomeric anthocyanins decreased by 61%, 65%, 75% and 58% in canned-in-water,
canned-in-syrup, non-clarified juice, and pureed samples, respectively, from 1 d to 6 mo of storage. However, polymeric color values increased from 13 to 30%, 18 to 30%, 17 to 34%, and 12 to 30% in canned-in-water, canned-in-syrup, clarified juice, non-clarified juice, and pureed samples, respectively from 1 d to 6 mo of storage. IQF berries demonstrated negligible changes in anthocyanins and percent polymeric color values during storage. For all samples, with the exception of purees (with a 22% loss), there were no changes in PCL over 6 mo storage. In black raspberries monomeric anthocyanins decreased by 59, 48, 75, 62, and 61% in canned-in-water, canned-in-syrup, clarified juice, non-clarified juice, and pureed samples, respectively, from 1 d to 6 mo of storage. However, polymeric color values increased from 6 to 22%, 5 to 21%, 9 to 31%, 4 to 28%, and 8 to 24% in canned-in-water, canned-in-syrup, clarified juice, non-clarified juice, and pureed samples, respectively, from 1 d to 6
mo of storage. ORAC values remained relatively stable over 6 mo of storage for all samples. IQF berries demonstrated negligible changes in anthocyanins, antioxidant capacity and percent polymeric color values during storage. In blueberries monomeric anthocyanins decreased 73%, 68%, 69%, 67%, and 74% % in canned-in-water, canned-in-syrup, clarified juice, non-clarified juice, and pureed samples, respectively, from 1 d to 6 of storage. An increase in polymeric color values coincided with decreases in monomeric anthocyanins during storage. Polymeric color values increased from1 to 12%, 1 to 26%, 1 to 17%, 1 to 25% and 1 to 42% in canned-in-water, canned-in-syrup, clarified juice, non-clarified juice, and pureed samples, respectively, from 1 d to 6 mo of storage.
Impacts
IQF berries retain comparable levels of monomeric anthocyanins and antioxidant capacity as fresh berries over six mo storage indicating they are an excellent alternative source of antioxidant-rich polyphenolics. All processed berry products (canned, juices, purees) exhibited greater than 50% losses of monomeric anthocyanins over six mo storage indicating processed berries are inferior to fresh and IQF fruit in regard to anthocyanin content. The antioxidant capacity of processed products remained relatively stable during storage in spite of significant losses of monomeric anthocyanins, suggesting that polymeric anthocyanins formed during storage have comparable radical scavenging capacity as monomeric anthocyanins. More research is needed to identify and determine the bioavailability of polymeric anthocyanins that form in processed berries during storage.
Publications
- No publications reported this period
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Progress 02/15/05 to 02/14/06
Outputs
Fresh blackberries, black raspberries, and blueberries are an excellent source of polyphenolics and antioxidant capacity, but information is lacking on how different processing methods influence their polyphenolic content. In this study we determined how different processing methods affect the polyphenolic content of the berries. Blackberries were evaluated as fresh, canned in water, canned in syrup, puree, and clarified and non-clarified juices. Processed samples were evaluated by HPLC for anthocyanin, flavonol, and ellagitannin content. Fresh black raspberries were evaluated frozen, canned in water, canned in syrup, puree, and clarified and non-clarified juices. Samples were analyzed for total phenolics, total monomeric and polymeric anthocyanins, and oxygen radical absorbing capacity (ORAC). Pies prepared from blueberries canned in water, or frozen blueberries were analyzed by HPLC for polyphenolic content and ORAC. For blackberries there were no differences in
polyphenolic composition and content among clarified and non-clarified juices, however, the juices had 45-59% higher flavonols, 21-27% higher anthocyanins, and 50% lower ellagitannins than fresh berries. The ellagitannin losses were attributed to seed removal during the juicing process. Compared to fresh berries, purees had 23% higher anthocyanins and 42% higher ellagitannins. Fresh berries and purees had similar levels of flavonols. Canned berries in water and syrup had 20-24% higher anthocyanins, and 47-54% higher ellagitannins compared to fresh berries, but only canned-in-water berries had higher levels of flavonols. For black raspberries, levels of total phenolics, ORAC, and total anthocyanins of IQF fruit decreased 8, 10, and 20%, respectively, compared to fresh berries. Puree total phenolics remained unchanged, but ORAC decreased by 40%, and total anthocyanins by 60%. There were decreases in total phenolics, ORAC and total anthocyanins in non-clarified (14, 45, and 44% losses,
respectively) and clarified (21, 44, and 51% losses, respectively) juices. Canned-in-water and canned in syrup samples decreased in total phenolics by 12% and 10%, respectively, anthocyanins by 38% and 40%, respectively and ORAC by 41% and 53% respectively. Polymeric color was observed only in heat-processed samples. Blueberries canned in water and pies made from blueberries canned in water had comparable levels of anthocyanins as fresh berries, but frozen blueberries and pies made from frozen fruit, had 17% and 23% lower anthocyanins than fresh berries. The frozen berries had comparable levels of total flavonols as fresh berries, but blueberries canned in water, pies made from blueberries canned in water, or from frozen blueberries, had 14% to 20% lower total flavonols than fresh berries. Blueberries canned in water had comparable levels of chlorogenic acid and ORAC values as fresh berries, whereas pies made from blueberries canned in water, or from frozen blueberries, had 10% lower
levels of chlorogenic acid. ORAC values for frozen berries, pies made from blueberries canned in water, or from frozen blueberries decreased 11%, 14%, and 26%, respectively compared to fresh berries.
Impacts
Canned, pureed and juiced blackberry products have considerably higher levels of polyphenolics than fresh blackberries, indicating they are excellent alternative sources of antioxidant-rich polyphenolics. Freezing results in minor losses of polyphenolics and antioxidant capacity in black raspberries, but preservation methods involving thermal treatments cause significant losses of anthocyanins and antioxidant capacity in the fruit. Methods are needed to prevent losses of anthocyanins and antioxidant capacity in thermally processed black raspberry products. Antioxidant-rich polyphenolics were well retained in canned blueberries, but freezing and baking result in moderate losses. Although different forms of processed blueberries have lower levels of polyphenolics and antioxidant capacity than fresh berries, they are still a good and readily available source of dietary antioxidants.
Publications
- No publications reported this period
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