Source: UNIV OF IDAHO submitted to
NOVEL EXTRACTION AND DEHYDRATION TECHNOLOGIES FOR RETENTION OF BIOACTIVE COMPOUNDS IN SMALL FRUITS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0210736
Grant No.
(N/A)
Project No.
IDA01365
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Jul 1, 2007
Project End Date
Jun 30, 2012
Grant Year
(N/A)
Project Director
Nindo, CA, IL.
Recipient Organization
UNIV OF IDAHO
875 PERIMETER DRIVE
MOSCOW,ID 83844-9803
Performing Department
School of Food Science
Non Technical Summary
Current protocols used in small fruit processing industry need improvement to maximize the recovery of pigments and retention of bioactive compounds that contribute to human wellbeing. Microwave energy or power ultrasound may be used to improve extraction of anthocyanin pigments in small fruits prior to concentration or drying. The purpose of this project is to produce small fruit juice concentrates or powders with added value by applying novel extraction and drying methods. Investigation of novel strategies to enhance anthocyanin recovery and retention of antioxidants from small fruits will provide information needed to improve the processing protocols.
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
5011120200010%
5011123200010%
5011139200010%
5011139202070%
Goals / Objectives
To add value and retain the health benefits in selected fruits from the Pacific Northwest region by using novel extraction, evaporation and drying methods to produce concentrates or powders. The specific objectives are (1) to apply microwave energy and/or power ultrasound to extract juices from selected fruits; (2) to investigate the influence of extraction and drying processes on chemical and thermo-physical properties of the dehydrated extracts; and (3) to determine the effect of novel drying technologies, either singly or in combination with other supplemental heating, in improving product quality and drying system throughput.
Project Methods
The proposed research will involve collaboration with small fruit processors in the Pacific Northwest to specifically use their commercial production facilities as the starting point to evaluate anthocyanin recovery and antioxidant activity during processing of juice. Samples will be collected directly after raw material reception, maceration and heating, enzyme treatment, and filtration. To increase the recovery of anthocyanins, the macerated fruit will be exposed to microwave energy and power ultrasound. Microwave energy will be applied from a 2450MHz generator with suitable controls to measure forward and reflected power. The product will be heated at different power levels (1.0, 2.0, and 4 Watts/g) for 0.5, 1.0, 1.5, and 2.0 minutes to determine the effect of power level and extraction time on anthocyanin recovery and total antioxidant activity. The microwave extraction and chemical analysis will be done at Washington State University (WSU) in collaboration with Dr. Juming Tang and Dr. Joe Powers, respectively. The second approach will be to extract bioactive compounds from small fruits using a laboratory scale power ultrasound (UP200S, Dr. Hielscher GmbH, Teltow, Germany). The UP200S has sonotrodes with various configurations that give different power output. Temperature during extraction and the effect of extraction media (ethanol and sulfured water) are important parameters that will be investigated. The power ultrasound experiments will be done at WSU Department of Food Science in collaboration with Dr. Barry Swanson. Further, extracts obtained after microwave and/or power ultrasound treatments will be analyzed for anthocyanin content and total antioxidant activity. Anthocyanin content will be measured following the pH differential method by correcting the pH to 4.5 and 1.0 then measuring absorbance at 520 nm and 700 nm using UV-visible spectrophotometer. The total antioxidant activity of extracts will be analyzed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Absorbance will be recorded at 515 nm at different time intervals and for up to 2 hours or until the readings become steady. The DPPH method, for antioxidants that are more soluble in organic solvents, will be compared with the modified 2,2-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) method. The data generated will be analyzed statistically to explain the effect of microwave and power ultrasound on extraction process. Collaboration with MCD Technologies Inc. (Tacoma, WA), the manufacturers of Refractance Window drying equipment, will allow the establishment of drying parameters for the extracts. To effectively dry the materials on the Refractance Window system, feed with appropriate consistency is important. AR2000 rheometer (TA Instruments, New Castle, DE) will be used to measure rheological properties of extracts. Since extraction procedures may affect the chemical and thermophysical properties of product, the glass transition temperature (Tg) of dehydrated extracts will also be determined using a modulated differential scanning calorimeter (DSC Q200, TA Instruments, New Castle, DE).

Progress 07/01/07 to 06/30/12

Outputs
OUTPUTS: In addition to outputs indicated in the last reporting period, one undergraduate student (Jacob Jenott) worked on the project in 2012 to gain research experience. One other graduate student (Amir Golmohamadi) received partial support while working on this project. The availability of a 20 kHz continuous flow ultrasound equipment facilitated the work of another graduate student (Jeremiah Dubie) to investigate the extraction of antioxidants from mustard meal - a byproduct of oilseed processing that is of vital economic importance to Idaho and the Pacific Northwest region in general. One poster was presented at IFT meeting in Las Vegas NV (June, 2012) and another at ASABE meeting held in Dallas, TX (August 2012). One paper on mango drying was published in the Journal of Food Engineering in 2012. PARTICIPANTS: One graduate student (Amir Golmohamadi) was supported with funds from this project. One undergraduate student (Jacob Jenott) gained research experience learning how to analyze antioxidants in fruits. TARGET AUDIENCES: Fruit, vegetable, and oilseed processors; equipment manufacturers, and researchers. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Refractance window (RW) drying is a novel drying method that is demonstrated to preserve various quality attributes of dehydrated foods. This drying technique was tested with mango puree and produced mango powder with quality comparable to that obtained via freeze drying, but was better than either drum dried or spray dried mango powders. The colors of RW-dried mango powder and reconstituted mango puree were also comparable to the freeze-dried (FD) products. However, those two treatments (RW and FD) were significantly different from drum-dried (darker) and spray dried (lighter) powders. The results of the mango drying study was published in peer reviewed journals and disseminated at professional meetings (2012 IFT Annual Meeting in Las Vegas NV). The resources helped to train graduate students and support undergraduate research experience. Another study was concerned with ultrasound assisted extraction of bioactive compounds in red raspberries. Ultrasound in the 20 to 1000 kHz range show unique propagation characteristics in fluid media and possess energy that can break down fruit matrices to facilitate the extraction of valuable bioactive compounds. Red raspberries are also known to carry significant amounts of antioxidants, including ellagitannins and anthocyanins that are important for human health. The goal was to investigate the effects of ultrasound frequencies associated with cavitation (20 kHz) and microstreaming (490 and 986 kHz) on total antioxidant activity (AOA), total phenolics content (TPC), and total monomeric anthocyanin content (ACY) of red raspberry puree prepared from crushed berries. Sonication at 20 and 490 kHz significantly (p<0.05) affected the AOA, ACY, and TPC of red raspberry puree, while 986 kHz had no significant effect on ACY and AOA. Sonication beyond 10 minutes (and up to 30 minutes) using 20 kHz either produced no change or caused a drop in AOA and ACY. However, for 986 and 20 kHz, TPC, increased by 10% and 9.5% respectively after 30 minute compared to the control. At 20 kHz, AOA and ACY increased by 17.3 % and 12.6% after 10 minutes. It was demonstrated that 20 kHz ultrasound treatment, when limited to 10 minutes, was the most effective for extraction of bioactive compounds in red raspberry compared to 490 and 986 kHz although the effect could be similar at the higher frequencies if different amplitudes are used. This technique has potential for extraction of bioactive compounds in other fruits and vegetables for diverse applications in food and health products. One graduate student (Amir Golmohamadi) was supported partially by funds from this project.

Publications

  • Caparino, O.A., Tang, J., Nindo, C.I., Sablani, S.S., Powers, J.R. and Fellman, J.K. 2012. Effect of drying methods on the physical properties and microstructures of mango (Philippines "Carabao" var.) powder. J. Food Engineering 111(1):135-148.
  • Dubie, J.S., Morra, M., and Nindo, C.I. 2012. Extraction of antioxidants from mustard (Brassica juncea) seedmeal using high-intensity ultrasound. ASABE Annual International Meeting, Dallas, TX. August 2012.
  • Golmohamadi, A., Moller, G., Powers, J.R., Nindo, C.I. 2012. Effect of ultrasound treatment on antioxidant activity, total phenolics, and anthocyanin content of red raspberry puree. Institute of Food Technologists (IFT) Annual Meeting and Expo, Las Vegas, NV. June 2012.


Progress 01/01/11 to 12/31/11

Outputs
OUTPUTS: Power ultrasound (20 kHz) is applied to assist in the extraction of bioactive compounds in selected Northwest berries (huckleberries and red raspberries) and Brassicaceae seed meals (BSM). Long process times that are typical with various juice processing operations (such as enzyme treatment and filtration) can be reduced significantly if power ultrasound is applied upstream of those processes to improve efficiency and juice yield. There is also the potential to recover valuable anthocyanins and other bioactive compounds from press-cakes or seed meals. We are investigating the effect of ultrasound extraction and drying of selected fruits, Brassicaceae seed meals, and developing value added fish gelatin-based edible films incorporating bioactive compounds. To achieve the project goals, the same approach of applying novel extraction and dehydration technologies may be extended to other fruit, seed, and vegetable processing operations to increase co-product utilization and thereby improve returns to small fruit and/or oilseed growers. A physical system for ultrasound assisted extraction of red raspberry juice under continuous flow was built and is being tested at different frequencies. During the reporting period, one undergraduate student worked on the project to gain research experience and learn how to analyze antioxidants in foods. The training of graduate student (Amir Golmohamadi) was also partially supported by this project. Some preliminary data from this project was relied on to apply for a USDA grant that facilitated the recruitment of one graduate student (Jeremiah Dubie) to investigate the extraction of antioxidants from mustard meal - a byproduct of one oilseed crop that is of vital economic importance to the Pacific Northwest region. One poster was presented at IFT meeting in June (New Orleans, LA) and yet another was presented at a project directors meeting held in Washington, DC (Oct., 2011). Two other dissemination activities at scientific conferences (IFT and ASABE meetings) are planned in the coming year. PARTICIPANTS: Principal investigator (Caleb Nindo) worked on the project with graduate students Katrina Finley and Amir Golmohamadi (the latter was supported with funds from this project). One research support scientist, Binying Ye, assisted students with projects. TARGET AUDIENCES: Fruit and oilseed processors, fish processors, equipment manufacturers, and researchers. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
There is a growing interest to apply power ultrasound as a mild non-thermal method to extract valuable bioactive compounds available in the byproducts of fruit, seed, and vegetable processing. Novel food processing technologies, including power ultrasound and Refractance window (RW) drying, may be used to recover or process those bioactive compounds that, when applied in different food matrices, can promote the wellness of US consumers. The application and proper control of power ultrasound frequencies in the range of 20-100 kHz (known to cause cavitational effects) may improve the recovery of anthocyanins and other polyphenolics in fruits, seeds, or byproducts of fruit and vegetable processing. Application of ultrasound assisted extraction is environmentally friendly and has the potential to improve the recovery of those bioactives with minimal to no use of organic solvents. Novel drying methods that are rapid and cause only minimal thermal effects are important processing steps for maintaining the activity of such extracts. The Brassicaceae seed meal (BSM) materials being studied are regionally important byproducts of oilseed processing that are usually discarded although they are full of valuable bioactive compounds. Some of these BSM also contain antimicrobials that may be incorporated into food matrices to prepare other value added products, including edible films to extend shelf life, increase food safety, and hence increase the profitability of oilseed crops grown in Idaho and the Pacific Northwest (PNW) region. If these oilseed crops are fully integrated into PNW cereal-based cropping systems, the region will produce over 150 M gal of biofuel oils and nearly 0.3 M tons of seed meal with extractable residual bioactive compounds that could be used in diverse platforms, including the $39 billion functional foods and nutraceuticals sector - an industry that grew by 4% in 2010 (Nutraceuticals World, Sept. 2011).

Publications

  • Caparino, O.O., Tang, J., Nindo, C.I., Sablani, S.S., Powers, J.R., and Fellman, J.K. (2011). Physical characteristics and microstructures of mango powder (Philippines "Carabao" var.) made from different drying systems. Abstract IFT Annual Meeting and Expo, New Orleans, LA, June, 2011.
  • Tammineni, N.R., Unlu, G., Rasco, B., and Nindo, C.I. (2011). Physical and antioxidant properties of trout skin gelatin films with vitamin E analog. Abstract IFT Annual Meeting and Expo, New Orleans, LA, June, 2011.
  • Krishna, M., Nindo, C.I., and Min, S.C. (2011). Development of fish gelatin edible films using extrusion and compression molding. J. Food Engineering (2011), http://dx.doi.org/10.1016/j.jfoodeng.2011.08.002.


Progress 01/01/10 to 12/31/10

Outputs
OUTPUTS: Experiments were conducted to determine antioxidant activity of huckleberry extracts obtained with power ultrasound. The berries were a mix of Mountain huckleberries (Vaccinium membranaceum), Cascade huckleberries (V. deliciosum) and oval-leaved bilberries (V. ovalifolium). We also analyzed freeze-dried blueberry powder for antioxidant activity to compare the results with huckleberries. These small fruits from the Pacific Northwest region are rich in anthocyanins and antioxidants that are important for promoting human health. Juice was extracted from freeze-dried powders using power ultrasound (UAE) and conventional (with solvents and no sonication) methods. Power ultrasound is an emerging novel approach that may be used to extract juice with the aim of improving the retention of quality and health-promoting attributes of small fruits. During the reporting period, one undergraduate student (Ms. Kimberly Russell) worked on the project. We submitted one abstract and made a presentation at the Institute of Food Technologists (IFT) Meeting in Chicago IL, July 17-20, 2010. The student made a poster presentation that received 1st prize at the IFT Lewis & Clark Student Poster Competition. The training of graduate students (Ms. Katrina Finley and Amir Golmohamadi) was partially supported by this project. Ms. Finley is completing her thesis work with a planned graduation in the summer of 2011. Mr. Golmohamadi is designing protocol for ultrasound assisted extraction of red raspberry antioxidants using different frequencies and under continuous flow conditions. A research support technician (Ms. Binying Ye) now works half time, and having received training through the project, will continue to help students with their research. PARTICIPANTS: The Project Director (Caleb Nindo) relied on the preliminary results from this project to apply for extramural funds and to support students' research. The PD attended and presented a poster at the USDA NIFA Project Directors meeting held in Chicago IL and one undergraduate student gained research experience and had an opportunity to travel to IFT meeting to present results of her work and to network with other attendees from academia and the food industry. Graduate students trained/being trained: Ms. Katrina Finley and Amir Golmohamadi. TARGET AUDIENCES: Small fruit (berry) processors, equipment manufacturers, and researchers. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Application of power ultrasound in the frequency range of 20-100 kHz (with potential to cause cavitation effects in liquid media) may improve the recovery of anthocyanins and other polyphenolics in small fruits and present new opportunities for their utilization in a diversity of platforms to support the health of US consumers. We are currently testing slightly higher frequencies (490 kHz and 980 MHz) to investigate ultrasound micro-streaming effects on antioxidants in red raspberries. Reliance on chemical solvents to extract anthocyanins and other antioxidants from fruits may be reduced if aqueous extraction with power ultrasound (UAE) can achieve better or comparable results. Extracts of freeze-dried huckleberry and blueberry powder were prepared and analyzed for both water and lipid soluble antioxidants using photochemiluminescence technique. The lipid-soluble antioxidants quantities were not significantly different between the huckleberries and blueberries in the conventional extraction method or the power ultrasound extraction method. The water-soluble antioxidant quantities of the blueberries were higher than the water-soluble antioxidant quantities of the huckleberries in the conventional and power ultrasound extraction methods. The water-soluble antioxidant quantities of the conventional method are higher than the water-soluble antioxidant quantities of the power ultrasound method. This could indicate many things such as: 1) the 100% amplitude on the power ultrasound equipment (UP200S) was too high and destroyed the antioxidants, or 2) the samples were not run for a long enough time to fully extract the antioxidants. We'll continue the experiments to fully understand these outcomes. Fingerprints of volatile organic compounds (VOCs) in the extracts were obtained using an electronic nose. Noticeable differences can be observed between the freeze-dried samples of huckleberries and blueberries in the electronic nose analysis and the PCL assay analysis. The huckleberries only showed one major compound, methyl 2-methyl-propanoate; and the blueberries has one major compound, 3-methyl-2-butanone, and two minor compounds, methyl 2-methyl-propanoate and dimethylheptenal. We suspect that storage conditions after extraction might have caused the developments of certain VOCs. The detection of specific marker compounds in juice using electronic nose can potentially serve as a rapid method for detecting changes in quality (sensory) attributes.

Publications

  • Russell, K., Ye, B. and Nindo, C.I. 2010. Ultrasound assisted extraction and antioxidant activity of huckleberry and blueberry freeze-dried powder. Abstract IFT Annual Meeting, Chicago IL, July 17-20, 2010.


Progress 01/01/09 to 12/31/09

Outputs
OUTPUTS: Both ultrasound-assisted (UAE) and conventional (with solvents and no sonication) extraction methods were used to extract anthocyanins and antioxidants from berries, including red raspberries and huckleberries. These berries and other small fruits produced in the Pacific Northwest are rich in anthocyanins and antioxidants that promote human health. Ultrasound assisted extraction is a novel approach that can potentially improve the retention of quality and health-promoting attributes in berry fruits after processing. Two abstracts were submitted and presented at two professional meetings in 2009 (IFT Anual Meeting in Anaheim CA and ASABE Annual International Meeting in Reno NV) and a manuscript is in preparation for publication. A graduate student (Katrina Finley) is working on the project and the results obtained will form part of her M.S. thesis. One undergraduate student has gained research experience through this project and another graduate student has been recruited to continue working to meet the goals of the project. A research support staff (Binying Ye) has received training through the project and is helping students with their research. PARTICIPANTS: Caleb Nindo (project director) has relied on preliminary results from this project to apply for extramural funds. Graduate students: Katrina Finley and Kyoung-Joo Lee (both from the Univeristy of Idaho/Washington State University School of Food Science). Kimberly Russell (gained undergraduate research experience). Drs. Gustavo Barbosa and Joseph Powers (Washington State University) kindly allowed the use of equipment in their respective laboratories. TARGET AUDIENCES: The target audiences include berry growers, processors, equipment manufacturers as well as researchers. PROJECT MODIFICATIONS: None

Impacts
Controlled application of power ultrasound can potentially improve the recovery of anthocyanins from berries and present new opportunities for their utilization in diverse platforms to support the health of US consumers. Reliance on chemicals to extract anthocyanins and other antioxidants from berries may be reduced if aqueous extraction with power ultrasound (UAE) can achieve better or comparable results. Huckleberry and red raspberry extracts were prepared in a laboratory-scale ultrasonic processor (UP400S) with maximum amplitude setting and at different extraction times. The following solvent combinations were used for huckleberries: 1) 100% DI water [A] + huckleberry (5min), 2) A + huckleberry (10min), 3) A + huckleberry (15min), 4) 1.5M HCl-95% ethanol (15:85) [B] + huckleberry (5min), 5) B + huckleberry (10min), 6) B + huckleberry (15min), and 7) conventional extraction with 80% methanol. Total solids in huckleberries ranged between 19.90~19.96% while total anthocyanin contents, analyzed by pH-differential method, were 32.05, 22.19, 26.41, 73.77, 63.06, 70.93, 271.50 Abs/g, respectively. Total antioxidant activity was highest for conventional extraction 7) and lowest for and 5). Acidified ethanol gave more anthocyanin recovery than aqueous extraction while 80% methanol was the highest. Longer extraction time (10 min) yielded less anthocyanin possibly due to temperature-sensitiveness of anthocyanin. Extending extraction time after the cell walls are adequately ruptured to release cell contents may not contribute to better yields. Statistical analysis of the relationship between anthocyanin content and total antioxidant activity in huckleberry extracts showed clear negative correlation (r = -0.96). We will continue the investigations by varying the power level and develop protocols based on continuous circulation of the fruit puree. Red raspberry extractions with ethanol as solvent, whether ultrasound assisted or by conventional method, all showed highest yields of anthocyanins when compared to water. Ultrasound assisted extraction of red raspberry with water as a solvent had a higher content of anthocyanins even at 5 minute run time (1.19 mg/L) versus the conventional extraction (0.67 mg/L), indicating that it is possible to achieve comparable yields with shorter processing times. This demonstrates that with ultrasound, chemical solvents could be minimized or eliminated from the process while still achieving anthocyanin recovery comparable to conventional ethanol extraction (1.33 mg/L). These results have potential to benefit juice processors and help improve the quality of berry juice products.

Publications

  • Finley, K. and Nindo, C.I. 2009. Ultrasound assisted extraction of anthocyanin and total antioxidant activity of red raspberries. Abstract IFT Annual Meeting, Anaheim CA, June 6-9, 2009.
  • Lee, K.J., Powers, J.R. and Nindo, C.I. 2009. Power ultrasound assisted extraction to retain anthocyanins and antioxidants in huckleberries. Abstract ASABE Annual International Meeting, Reno, NV, June 21-21, 2009.


Progress 01/01/08 to 12/31/08

Outputs
OUTPUTS: Protocols were developed for ultrasound assisted extraction and analysis of anthocyanins and total antioxidants in huckleberries. Huckleberries and other small fruits produced in the Pacific Northwest are rich in anthocyanins and other antioxidants that promote human health. Ultrasound assisted extraction (UAE) is a novel approach that can potentially improve the retention of quality and health-promoting attributes in berry fruits after processing. The objective was to apply power ultrasound to assist in the extraction process by using different solvents. Anthocyanin recovery and antioxidant activity of huckleberry extracts obtained by conventional extraction and UAE was compared. The anthocyanin content and total antioxidant activity was determined by the previously developed pH differential and DPPH (2,2-diphenyl-1-picrylhydrazyl) methods. Preliminary results of this study were presented as component of a paper at the 50th international meeting of CSBE, Vancouver BC. Two other abstracts have been submitted for presentation at next IFT and ASABE meetings. A graduate student has been working on the project and the results obtained will form part of her thesis. PARTICIPANTS: Graduate students: Kyoung-joo Lee and Katrina Finley TARGET AUDIENCES: Berry processors and researchers PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Controlled application of power ultrasound can potentially improve the recovery of anthocyanins from Pacific Northwest berries and present opportunities for their utilization in diverse platforms to support the health of US consumers. Reliance on chemicals to extract anthocyanins and other antioxidants from berries may be reduced if aqueous extraction with power ultrasound can achieve better or comparable results. The huckleberry extracts were prepared in a laboratory-scale ultrasonic processor (UP400S) with maximum amplitude setting, at different extraction times, and with various solvents. The following solvent combinations were used: 1) 100% DI water [A] + huckleberry (5min), 2) A + huckleberry (10min), 3) A + huckleberry (15min), 4) 1.5M HCl-95% ethanol (15:85) [B] + huckleberry (5min), 5) B + huckleberry (10min), 6) B + huckleberry (15min), and 7) conventional extraction with 80% methanol. Total solids in huckleberries ranged between 19.90~19.96% while total anthocyanin contents, analyzed by pH-differential method, were 32.05, 22.19, 26.41, 73.77, 63.06, 70.93, 271.50 Abs/g, respectively. Total antioxidant activity was analyzed by DPPH method, and results from high to low for the different extraction protocols, was 7), 1), 3), 2), 4), 6) and 5). Acidified ethanol gave more anthocyanin recovery than aqueous extraction while 80% methanol was the highest. Longer extraction time (10 min) yielded less anthocyanin possibly due to temperature-sensitiveness of anthocyanin, and as ultrasound treatment time was extended more anthocyanin was extracted because cavitation effects of ultrasound set in to enhance the release of metabolites from the cell matrices. Pearson's correlation coefficients were used to study the relationships between total anthocyanin contents and total antioxidant activities, and statistical analysis showed clear negative correlation (r = - 0.96) between anthocyanin content and total antioxidant activity in huckleberry extracts. We will continue the investigations on the effect of extending ultrasound treatment beyond 15 minutes, continuously circulating the mixture, and varying the power level. The effect of ultrasound on huckleberry anthocyanin has not been reported previously. These results will benefit juice processors to help improve the quality of their product by using different processing methods.

Publications

  • No publications reported this period


Progress 07/01/07 to 12/31/07

Outputs
OUTPUTS: Drying of sugar-rich food products like berries is ordinarily problematic. In this project, three drying methods (spray drying, freeze drying, and Refractance Window drying) were set with the objective of successfully producing blueberry powder. Blueberry juice concentrate with 64.5% dissolved solids was dried by three methods; spray drying, freeze drying, and Refractance Window drying. Various amounts of drying aids such as corn maltodextrin were added to the juice concentrate before being diluted with deionized water to a consistency that could either be applied on the belt of the RW dryer or pumped into the atomizer of the spray dryer. The freeze-dried product was prepared in a pilot-scale freeze-dryer (Freeze Mobile 24, Vertis Company Inc., Gardiner, NY) with heating plate temperature set at 20 degrees Celcius and 3.3kPa chamber absolute pressure. The samples were collected after drying for analysis of anthocyanins. The purpose of these activities was to compare the recovery blueberry anthocyanins after drying. The blueberry juice was formulated with various amounts of starch or maltodextrin before drying, then the anthocyanin content of dried materials were assayed using pH differential method. The level of anthocyanins in berries is important as it may be indicative of their antioxidant potential. We visited a fruit juice processing company in the Northwest to get familiar with the juice processing operations and take note of particular unit operations that may contribute to loss of bioactive compounds in berries. The results of anthocyanin retention were published in an abstract and presented at the annual Institute of Food Technologists (IFT) meeting in Chicago, July 28-Aug 1, 2007. Protocols for the analysis of antioxidants have been developed and will be used in subsequent experiments to analyze the total antioxidant activity of dehydrated Northwest berry products. A review article describing the novel Refractance Window drying method being used in this project was published during the same period. One graduate student was recruited and will investigate the effect of extraction and drying methods on bioactive compounds in Northwest berries. PARTICIPANTS: Graduate student, Lee, K.J. did the analysis of anthocyanins in blueberry powder. This was done in collaboration with Dr. Joe Powers at Washington State University. MCD Technologies Inc (Tacoma, WA) provided blueberry powder dried by the Refractance Window method. TARGET AUDIENCES: The target audiences include US berry growers, processors, equipment manufacturers as well as researchers. PROJECT MODIFICATIONS: None

Impacts
Quantifying the level of anthocyanins in dehydrated fruit products is beneficial to US consumers because it will help them in making informed choices on foods that have potential to provide more health benefits. The information will support the processing and marketing of Northwest berry products that satisfy consumers' needs. In fruit processing operations, for example, innovative approaches are needed to ensure that the healthful benefits that fruit products offer are retained to the fullest extent possible after processing. Investigation of novel technologies such as Refractance Window drying (RW) is needed to support production of the healthiest fruit products possible. To promote long-term use of berries as ingredients in baked goods, cereals, and beverages, processing technologies must be selected that are cost-effective and efficient at maximizing the retention of antioxidants initially present in the berries. Total anthocyanin contents analyzed by pH-differential method were from 41.2 to 46.3 Abs/g for RW dried blueberry with and without drying aid and 47.52 Abs/g for freeze dried counterpart. A spray-dried blueberry powder that was formulated with rice oligodextrin showed an absorbance of 61.7 Abs/g. The anthocyanin content of blueberry concentrate powders prepared using RW were similar with and without use of drying aids. Anthocyanins are more stable when concentrated or dehydrated and their recovery during the spray drying process most likely improved due to the encapsulating effect of the rice polysaccharide. It appears that RW is a relatively inexpensive alternative to freeze drying for preparation of blueberry juice concentrate powder without addition of drying aids. Investigations are continuing to examine drying conditions that may improve the retention of anthocyanin pigments and other antioxidants in Northwest berries.

Publications

  • Lee, K.J., Nindo, C.I., Tang, J., Powers, J.R. Retention of Anthocyanins during Drying of Blueberry Concentrate. Annual IFT Meeting, Chicago. July 28- Aug. 1, 2007. (Abstract).
  • Nindo, C.I., Tang, J. 2007. Refractance Window Technology: A novel contact drying method. Drying Technology, 25(1): 37-48.