Source: UTAH STATE UNIVERSITY submitted to NRP
EFFECTS OF ULTRASOUND ON THE VISCOSITY OF CONCENTRATED MILKS AND BIOFILM FORMATION ON PROCESSING EQUIPMENT
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
HATCH
Reporting Frequency
Annual
Accession No.
1009719
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Jul 1, 2016
Project End Date
Jun 30, 2021
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
UTAH STATE UNIVERSITY
(N/A)
LOGAN,UT 84322
Performing Department
Nutrition, Dietetics and Food Sciences
Non Technical Summary
The United States is the world's largest single-country producer of powdered milk products (skim milk powder, nonfat dry milk, and milk protein concentrates combined), producing over 1 million metric tons annually. Of this, 52% is exported. In order to expand the U.S. powdered milk production, limitations in manufacture need to be addressed. Limitations include the formation of biofilms (microorganisms and protein) on processing equipment, which increase the need to clean equipment and contaminates the final product leading to product defects. Additionally, increasing the solids content of the liquid, concentrated milk prior to spray drying would reduce energy costs associated with production. We will investigate the effects of ultrasound on the production of biofilms on plate heat exchangers and the viscosity of concentrated milks. The use of ultrasound during thermal processing of milk may reduce biofilm formation, which may extend thermal processing run times and reduce the microbial load in the final product. Ultrasound may also reduce the viscosity of concentrated milk allowing higher solids concentrations to be spray dried during milk powder production, which is an economical advantage. Outcomes of this project will be increased knowledge on how ultrasound influences biofilm formation and the viscosity of concentrated milks to increase the quality and quantity of U.S. milk powders.
Animal Health Component
50%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
50134501000100%
Knowledge Area
501 - New and Improved Food Processing Technologies;

Subject Of Investigation
3450 - Milk;

Field Of Science
1000 - Biochemistry and biophysics;
Goals / Objectives
We hypothesize that concentrated milk treated with ultrasound will have reduce viscosity allowing spray drying of higher solids milks and will minimize fouling of plate heat exchangers leading to a more economical drying process, extended processing times prior to equipment cleaning, and minimized microbial contamination in the final product.Objectives1. Measure the influence of temperature and solids content on the viscosity of concentrated milk products in static. The viscosity of each sample (50 mL) will be measured before and after ultrasound.a. Milk Protein Concentrate (MPC): 30 to 35% solids at 40 to 80 C.b. Skim Milk Protein (SMP) (34% protein): at 45 to 55% solids at 40 to 80 C.2. Based on the data obtained in objective 1, measure the influence of ultrasound on the viscosity of concentrated milk products using a flow through sonicator at multiple solids concentrations and temperatures. Calculate the acoustic power generated using the flow through system.3. Measure the changes in physiochemical properties of concentrated milk products after ultrasound (rancidity, sulfur compounds, color and pH).4. Determine the influence of ultrasound on biofilm formation in a plate heat exchanger using a flow-through sonicator at 70-73 C. Analyze biofilm for microbes and protein content and imaged via microscopy.
Project Methods
AcronymsMPC = dry milk protein concentraterMPC = reconstituted milk protein concentrateSMP = dry skim milk proteinrSMP = reconstituted skim milk proteinFor the purpose of this research, MPC evaporated to 31% solids and SMP evaporated to 47-50% solids before spray drying will be reconstituted. We will use both a static sonicator (3.2 mm titanium microtip and a 20 kHz Misonix Sonicator 3000; Misonix Inc., Farmingdale, NY) for small volume samples (50 mL) and a flow through sonicator (2 cm titanium tip and a 20 kHz Hielscher UIP500 W hd; Ringwood, NJ) for samples up to 6 L. For objective 1, MPC will be reconstituted to between 30 and 35% solids and the viscosity will be measured at temperatures between 40 and 80 C using a rotational viscometer (Fungi Lab, NY). SMP will be reconstituted to 45 to 55% solids and the viscosity will be measured at temperatures between 40 and 80 C. The application of ultrasound (10 s) at an amplitude of 216 microns for both 15 and 30 seconds will also be done on 50 mL of sample and the viscosity will be measured. Based on the results of the experiments described above, reconstituted MPC and SMP will be treated by ultrasound in objective 2 using a flow through sonicator and the influence of ultrasound on the viscosity will be determined. Samples sonicated using the flow through sonicator will be analyzed for rancidity (Fereidoon and Zhong, 2014), sulfur compounds (Dias and Weimer, 1989), color (Hunter Color meter), acoustic power (Martini, Potter, and Walsh, 2010) and pH (pH meter). A bench-scale plate heat exchanger (PHE) using 10 plates connected to the flow-through sonicator will be used for objective 4. The setting on the sonicator will be at 90% of maximum amplitude. Product temperature will be constantly monitored and a temperature of 72 to 73?C will be maintained with ±0.5?C change throughout the process. Fat-free milk will be procured from USU's Dairy Products Laboratory and either used directly (9.5-10% total solids) or the solids level will be adjusted to 20, 30, or 40% with the addition of nonfat dry milk. Two experimental conditions for each total solids level - no ultrasound (control) and ultrasound - will be used. A single round of ultrasound will be applied for a period of 5 min, followed by a 10 min interval of no ultrasound. This round will be repeated over 2 h, resulting in 8 × 5 min ultrasound, for a total of 40 min of ultrasound to product over a 2 h process. To assess quantity of biofilm formation, the PHE plates will be removed after experiments and will be analyzed via microscopy. Additionally, the biofilm material will be scraped off the plates with sterile swabs and the content will be analyzed for protein content and for total plate count. Bacterial aerobic plate counts will be conducted on plate count agar (Remel Inc., Lenexa KS) as described in Buehner et al. (2014) in duplicate.

Progress 07/01/16 to 06/30/21

Outputs
Target Audience:Food industry, food scientists, dairy processors Changes/Problems:None. What opportunities for training and professional development has the project provided?I trained two undergraduates (Logan Sherman and Jeffrey Jarman) and three graduate students on laboratory techniques required to conduct this research. How have the results been disseminated to communities of interest?Over the course of this project, I participated in 15 conferences at the national and international levels with graduate students. I also have 19 publications in peer reviewed journals. What do you plan to do during the next reporting period to accomplish the goals?This project is completed.

Impacts
What was accomplished under these goals? This project was based on the hypothesis that concentrated milk treated with ultrasound will have reduce viscosity allowing spray drying of higher solids milks and will minimize fouling of plate heat exchangers leading to a more economical drying process, extended processing times prior to equipment cleaning, and minimized microbial contamination in the final product. Milk protein concentrate was reconstituted to 30 to 44% solids (rMPC) and the viscosity was measured at temperatures ranging from 40 to 65 C. Skim milk protein concentrate was reconstituted to 46 to 64% solids (rSMP) and the viscosity was measured at temperatures ranging from 40 to 60 C. Overall, there was an increase in viscosity with an increase in solids content at each temperature tested for both rSMP and rMPC. The increase was exponential at 40 and 50 C in rSMP and was linear at 40, 50 and 60 C in rMPC. With rSMP, there was a 903.8 and 2012.6 % increase in viscosity at 50 and 40 C respectively compared to 60 C at 54% solids. With rMPC, there was a 900% and 2715% increase in viscosity at 50 and 40 C compared to 60 C at 34% solids. This shows the dramatic effect of temperature on the viscosity, with significantly higher viscosities at lower temperatures. We conducted studies on the effects of sonication on the viscosity of rSMP using a flow through sonication system to simulate a continuous operation. rSMP samples were reconstituted to a 3 L volume at 50, 52 and 54% TS and pumped at a flow rate of 1.8 L/ min for a total of 15 min before being sonicated and a sample was collected at this time point. The sonication flow cell had a 261 mL volume resulting in a 8.4 sec residence time (time sample was exposed to sonication) for the 1.8 L/min flow rate. For flow through sonication, samples were recirculated through the system. Samples were recirculated through the flow through system post sonication and samples were collected for viscosity measurements at 45 min for rSMP. For rSMP, % TS of ≥54 % in a continuous system required long heating times to form a continuous solution which resulted in age gelation of samples, therefore the highest TS used was 54. A decrease in viscosity of 16, 38 and 42% was observed with a TS of 50% at residence times of 10.1, 20.2 and 30.2 sec. A decrease in viscosity of 6, 9 and 13% was observed with a TS of 52% and a decrease in viscosity of 2, 16 and 22% was observed at a TS of 54% at residence times of 10.1, 20.2, and 30.2 sec. For rMPC at 32% TS, the viscosities were reduced by 19, 30 and 36% and at a 34% TS the viscosities were reduced by 24, 19 and 10% at times 10.1, 20.2 and 30.2 seconds in the flow-through sonication system compared to pre-sonication. During MPC processing, the sample is generally evaporated to 30-31% TS before spray drying. For the rMPC, the mean viscosity at 35% TS after 30.2 s residence time of sonication was lower than the mean viscosity of 30% TS prior to sonication. Also the mean viscosity at 34% TS after 10.1 sec of sonication was equivalent to that at 30% TS prior to sonication. Therefore, if MPC is concentrated to 34% TS via evaporation, only 10 s of sonication may be needed to obtain an equivalent viscosity as seen at 30% total solids. Furthermore, sonication of the 35% TS rMPC for 30 s would yield a viscosity, which was lower than that at 30% TS pre-sonication values. So, it may be possible to increase the solids content to approximately 35% TS of MPC prior to drying if sonication is used to reduce the viscosity to obtain an economical advantage. The pH values of sonicated samples were not statistically different from the non-sonicated samples. Vegetative cells and spores of thermophilic bacteria can survive milk pasteurization and affect quality of dairy products during shelf life and lead to fouling in plate heat exchangers. Coupling thermosonication with pasteurization may reduce the microbial load in fluid foods and enhance the product quality during shelf life and reduce fouling on dairy plant equipment. This study evaluated the effect of thermosonication along with heating in a lab-scale continuous system on the survival of Geobacillus stearothermophilus in milk at two different settings (setting 1: 27.7 s total heating time with or without 11.9 s of sonication; setting 2: 20.3 s total heating time with or without 7.1 s of sonication) with all equipment set at 72 °C. This study also investigated the effect of thermosonication along with heat on indigenous microflora in raw milk and milk quality assessed by pH, free fatty acid (FFA) content, and casein/total protein (CN/TP) content. Overall, thermosonication had higher log reductions for G. stearothermophilus vegetative cells, but the reduction was not significant overall. The log reductions for control were between 0.25-0.37 and treatment were 0.45-0.54 at setting 1. Thermosonication significantly decreased the indigenous microflora in milk as compared to heat alone at both settings. Longer residence times (setting 1) had significantly higher log reductions at week 0, and treatment samples had significantly higher reductions than control during storage time at both the settings. Thermosonication samples treated at setting 1 had significantly higher pH, lower FFA content, and higher CN/TP content at week 4, as compared to control. To investigate the effect of sonication on biofilm formation, SMP was added to pasteurized milk to obtain solids contents of 16, 29 and 39%. The same thermosonication system described above was used with recirculating the milk for 2 hours with no sonication (control) to allow for biofilm formation. For the treatment, we turned on the sonicator for 5 min, followed by no sonication for 10 min. Cold water was rinsed through the system to remove particulates and the plates were air dried. The plates were then rinsed in alkaline cleaner for 30 min, then left to soak overnight. The plates were then removed from the PHE and air dried. The weight of the plates was recorded and then scraped for biofilm solids. The average % reduction in plate weights with sonication was 41.8, 26.3 and 15.2 grams with milks containing 16, 29 and 39% solids. The biofilm material was placed in sterile tubes containing saline solution and vortexed for 5 min. These samples were analyzed for vegetative cells and spores. Vegetative cells were determined by direct plating of samples. The presence of spores was determined by heat shocking the samples, then plating. We observed both vegetative cells and spores in the material on the PHE plates for control and sonication. Although the sonication plates contained vegetative cells and spores, there was significantly less biofilm material on the plates. An increase in solids content and a decrease in temperature lead to an increase in viscosity of rSMP and rMPC. Additionally, there was a reduction in viscosity with the application of sonication in a batch system and in a continuous sonication system. Therefore, the application of sonication in a flow through system decreases the viscosity of concentrated milks and may be used to modulate the viscosity allowing higher solids going to the dryer, which would be an economical benefit to the dairy industry. Thermosonication using practical residence times in a lab-scale continuous system reduced the amount of indigenous bacteria in milk and may improve milk quality during its shelf life and reduce biofilm formation in dairy processing equipment since there is a reduction in microbial load.

Publications

  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Deshpande, V., & Walsh, M. K. (2021, February). Effect of thermosonication in a laboratory scale continuous system on the survival of thermophilic bacteria and indigenous microflora. International Food Research Journal.


Progress 10/01/19 to 09/30/20

Outputs
Target Audience:Food industry, food scientists, dairy processors Changes/Problems:None What opportunities for training and professional development has the project provided?I participated in 3 virtual international conferences with 2 poster presentations and one oral presentation. Additionally, I trained 1 PhD student. How have the results been disseminated to communities of interest?I have 4 publications published in international peer-reviewed journals in 2020 and 3 presentations at professional meetings. What do you plan to do during the next reporting period to accomplish the goals?We have completed the research associated with objectives 1 to 3 and will finish objective 4 in 2021.

Impacts
What was accomplished under these goals? Our previous results showed that thermosonication using practical residence times in a lab-scale continuous system reduced the viscosity of concentrated milk, may improve milk quality during its shelf life and reduce biofilm formation in dairy processing equipment since there is a reduction in microbial load. We proceeded to conduct scale up studies to confirm the results obtained with a lab scale thermosonicator. Thermosonication was integrated into a high-temperature short time pasteurization system which included a pre-heat plate heat exchanger (PHE) (set at 80°C), a PHE set at 75°C followed by a 15 s hold (pasteurization conditions), a flow through sonicator (11 s resident time, set at 73°) and a cooling PHE set at 0°C. To simulate continuous operation, milk was pumped at a flow rate of 1 L/min. Raw milk was warmed to 25-30 °C for each run. Samples were thermosonicated at 60 % amplitude and the temperature of the flow cell was maintained at 72 °C using a circulating water bath set at 73 °C. Additionally, this system had thermocouples before and after each PHE so we could monitor pasteurization conditions. Control samples flowed through the system with the sonicator turned off. Raw whole milk was passed through this system and evaluated for microbial count and biofilm weight and microbial composition. The average microbial count was significantly lower for thermosonication samples as compared to control after treatment and during shelf life. Control samples showed signs of curdling at 4 weeks while the treatment samples showed no signs of curdling at 6 weeks. To investigate the effect of sonication on biofilm formation, SMP was added to pasteurized milk to obtain solids contents of 16, 29 and 39%. The same thermosonication system described above was used while recirculating the milk for 2 hours with no sonication (control) to allow for biofilm formation. For the treatment, we turned on the sonicator for 5 min, followed by no sonication for 10 min. Cold water was rinsed through the system to remove particulates and the plates were air dried in place. The plates were rinsed in alkaline cleaner for 30 min, then left to soak overnight. The plates were then removed from the PHE and air dried. The weight of the plates was recorded and then scraped for biofilm solids. The average % reduction in plate weights with sonication was 41.8, 26.3 and 15.2 grams with milks containing 16, 29 and 39% solids. The biofilm material was placed in sterile tubes containing saline solution and vortexed for 5 min. These samples were analyzed for vegetative cells and spores. Vegetative cells were determined by direct plating of samples. The presence of spores was determined by heat shocking the samples, then plating. We observed both vegetative cells and spores in the material on the PHE plates for control and sonication. Although the sonication plates contained vegetative cells and spores, there was significantly less biofilm material on the plates.

Publications

  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Deshpande, V., & Walsh, M. K. (2020, June). Effect of thermosonication in a continuous system on indigenous microflora, milk quality and consumer acceptance. J. Food Processing Preservation, 44(9), e14666.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Hadeel, Y., Khalida, S.A, & Walsh, M. K. (2020, June). Antioxidant activity of sesame seed lignans in sunflower and flaxseed oils. Food Research(4(3)), 612-622.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Park, N., & Walsh, M. K. (2020, December). Physical and emulsion stabilizing properties of maltodextrin fatty acid polymers produced by lipase-catalyzed reactions in ethanol. Carbohydrate Polymers, 226.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Walsh, M. K., & Deshpande, V. K. (2020, February). Effect of thermosonication in a batch system on the survival of spore forming bacteria. To appear in International Journal of Dairy Technology, 73(3).
  • Type: Conference Papers and Presentations Status: Other Year Published: 2020 Citation: Presentations Park, N. (Presenter & Author), Walsh, M. K., AOCS Annual Meeting, "Characterization of thermostable immobilized lipases with respect to positional and substrate specificity during esterification," American Oil Chemists Society, Virtual. (June 2020 - 2020)
  • Type: Conference Papers and Presentations Status: Other Year Published: 2020 Citation: Presentations Park, N. (Presenter & Author), Walsh, M. K. (Author Only), Institute of Food Technologists, "The microbial inhibitory activities of maltodextrin esters against food-spoilage and pathogenic microorganisms," Institute of Food Technologists, Chicago, IL. (July 12, 2020 - July 15, 2020)
  • Type: Conference Papers and Presentations Status: Other Year Published: 2020 Citation: Presentations Walsh, M. K. (Author Only), Park, N. (Presenter & Author), American Society for Microbiology, "Vitro Microbial Inhibition and Mechanism of Action of Maltodextrin Fatty Acid Ester against Food-Related Microorganisms," ASM, Virtual. (June 2020)


Progress 10/01/18 to 09/30/19

Outputs
Target Audience:Food industry, food scientists, dairy processors Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?I participated in 2 international conferences with 4 poster presentations and one regional conference with 3 poster presentations for a total of 9 presentations during the 2019 year. Additionally, I trained 3 PhD students. How have the results been disseminated to communities of interest?I have 3 publications published in international peer-reviewed journals in 2019 and 9 presentations at professional meetings. What do you plan to do during the next reporting period to accomplish the goals?We will continue with the research outlined to complete objectives 3 and 4.

Impacts
What was accomplished under these goals? We have completed the research associated with objectives 1 and 2 of this research and initiated research associated with objectives 3 and 4. Vegetative cells and spores of thermophilic bacteria can survive milk pasteurization and affect quality of dairy products during shelf life. Coupling thermosonication with pasteurization may reduce the microbial load in fluid foods and enhance the product quality during shelf life and reduce fouling on dairy plant equipment. This study evaluated the effect of thermosonication along with heating in a lab-scale continuous system on the survival of Geobacillus stearothermophilus in milk at two different settings (setting 1: 27.7 s total heating time with or without 11.9 s of sonication; setting 2: 20.3 s total heating time with or without 7.1 s of sonication) with all equipment set at 72 °C. This study also investigated the effect of thermosonication along with heat on indigenous microflora in raw milk and milk quality assessed by pH, free fatty acid (FFA) content, casein/total protein (CN/TP) content, and reactive thiol content during storage time at the two settings. Overall, thermosonication had higher log reductions for G. stearothermophilus vegetative cells, but the reduction was not significant overall. The log reductions for control were between 0.25-0.37 and treatment were 0.45-0.54 at setting 1. Thermosonication significantly decreased the indigenous microflora in milk as compared to heat alone at both settings. Longer residence times (setting 1) had significantly higher log reductions at week 0, and treatment samples had significantly higher reductions than control during storage time at both the settings. Thermosonication samples treated at setting 1 had significantly higher pH, lower FFA content, and higher CN/TP content at week 4, as compared to control. Thermosonication did not have a significant effect on the reactive thiol content of milk samples. Thermosonication using practical residence times in a lab-scale continuous system may improve milk quality during its shelf life and reduce biofilm formation in dairy processing equipment since there is a reduction in microbial load. Results from this study need to be verified in a scale up study employing pasteurization conditions.

Publications

  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Hadeel, Y., Khalida, S.A, & Walsh, M. K. (2019, December 22). Antioxidant activity of sesame seed lignans in sunflower and flaxseed oils. Food Research(4(3)), 612-622.
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Lee, S.M., Nummer, B. A., Wagh, A., & Walsh, M. K. (2019, March). Antilisterial activity of lactose fatty acid esters in milk. Food and Nutrition Sciences, 10, 750-760.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Nam, S. H., Wagh, A., Martini, S., & Walsh, M. K. (2016, November 01). Sensory characterisation of a high-protein beverage. International Journal of Dairy Technology, 70(3), 432-438.
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Park, N., & Walsh, M. K. (2019, December). Physical and emulsion stabilizing properties of maltodextrin fatty acid polymers produced by lipase-catalyzed reactions in ethanol. Carbohydrate Polymers, 226.
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Walsh, M. K., & Deshpande, V. K. (2019, December 18). Effect of thermosonication in a batch system on the survival of spore forming bacteria. To appear in International Journal of Dairy Technology. 1286
  • Type: Conference Papers and Presentations Status: Other Year Published: 2019 Citation: Presentations Najm, T. (Presenter & Author), Walsh, M. K. (Author Only), Institute of Food Technologists, "Comparison of four purification methods to purify lipase from thermophilic bacteria," Institute of Food Technologists, New Orleans, LA. (July 2019
  • Type: Conference Papers and Presentations Status: Other Year Published: 2019 Citation: Presentations Park, N. (Presenter & Author), Walsh, M. K. (Author Only), Institute of Food Technologists,, "Physicochemical and emulsion stabilizing properties of maltodextrin esters produced by lipase-catalyzed reactions with ethanol," Institute of Food Technologists,, New Orleans, LA. (July 2019)
  • Type: Conference Papers and Presentations Status: Other Year Published: 2019 Citation: Presentations Deshande, V. (Presenter & Author), Walsh, M. K. (Author Only), American Dairy Science Association, "Effect of sonication combined with heat to improve the microbial quality of milk," American Dairy Science Association, Ohio. (June 2019)
  • Type: Conference Papers and Presentations Status: Other Year Published: 2019 Citation: Presentations Deshpande, V. (Presenter & Author), Walsh, M. K. (Author Only), American Dairy Science Association, "Effect of thermosonication in a batch system on the survival of thermophilic bacteria in milk," American Dairy Science Association, Ohio. (June 2019)
  • Type: Conference Papers and Presentations Status: Other Year Published: 2019 Citation: Presentations Walsh, M. K. (Author Only), Najm, T. (Presenter & Author), Bonneville Section of IFT Regional Meeting, "Comparison of purification methods to purify lipases from thermophilic bacteria," Bonneville Section of IFT Regional Meeting. (April 2019)
  • Type: Conference Papers and Presentations Status: Other Year Published: 2019 Citation: Presentations Vidita, D. (Presenter & Author), Walsh, M. K. (Author Only), Bonneville Section of IFT Regional Meeting, "Effect of thermosonication to improve the microbial quality of milk," Bonneville Section of IFT Regional Meeting, Salt Lake City, UT. (April 2019)
  • Type: Conference Papers and Presentations Status: Other Year Published: 2019 Citation: Presentations Walsh, M. K. (Author Only), Park, N. (Presenter & Author), Bonneville Section of IFT Regional Meeting, "Physicochemical and emulsion stabilizing properties of maltodextrin esters," Bonneville Section of IFT Regional Meeting, Salt Lake City, UT. (April 2019)


Progress 10/01/17 to 09/30/18

Outputs
Target Audience:Food industry, food scientists, dairy processors Changes/Problems:None What opportunities for training and professional development has the project provided?I participated in one international conference during the 2018 year, and I trained 3 PhD students. How have the results been disseminated to communities of interest?I had 4 publications published in international peer-reviewed journals in 2018. I also presented the information related to this project at one international conference. What do you plan to do during the next reporting period to accomplish the goals?We will continue with the research outlined to complete objective 3 and then begin on research associated with objective 4.

Impacts
What was accomplished under these goals? We have completed the research associated with objectives 1 and 2 of this research and initiated research associated with objective 3. To complete objective 2, we sonicated rMPC in a continuous-flow pilot scale sonicator at a flow rate of 1.8 L/min for a total of 60 min before being sonicated. rMPC at concentrations of 30, 32, and 34% total solids in a total of 3 L were used and the temperature was maintained at 60 C to simulate processing conditions. For the continuous operation, rMPC was sonicated (Heischler UIP500hd, Ringwood, NJ, USA) at 90% amplitude for a total of 6 min. The sample flow cell had a 261 mL volume resulting in a 8.4 sec residence time and samples were collected at 10.1, 20.2 and 30.2 seconds residence time (or at times 2, 4 and 6 min). Initially, the rMPC was allowed to recirculate for 60 min to reach a steady state. Samples were allowed to run in the continuous operation post sonication and samples were collected at 45 min for rMPC. At 30% TS, the viscosities were reduced by 30, 36 and 46% at times 10.1, 20.2 and 30.2 seconds compared to before sonication. At 32% TS, the viscosities were reduced by 19, 30 and 36% and at a 34% TS the viscosities were reduced by 24, 19 and 10% at times 10.1, 20.2 and 30.2 seconds compared to pre-sonication. Overall, there was an increase in viscosity with an increase in solids content and a decrease in viscosity after sonication. During MPC processing, the sample is generally evaporated to 30-31% TS before spray drying. For the rMPC, the mean viscosity at 35% TS after 30.2 s residence time of sonication was lower than the mean viscosity of 30% TS prior to sonication. Also the mean viscosity at 34% TS after 10.1 sec of sonication was equivalent to that at 30% TS prior to sonication. Therefore, if MPC is concentrated to 34% TS via evaporation, only 10 s of sonication may be needed to obtain an equivalent viscosity as seen at 30% total solids. Furthermore, sonication of the 35% TS rMPC for 30 s would yield a viscosity, which was lower than that at 30% TS pre-sonication values. So, it may be possible to increase the solids content to approximately 30% TS of MPC prior to drying if sonication is used to reduce the viscosity to obtain an economical advantage. Additionally, after sonication and continued flow through the sample without sonication for 45 min, the viscosity of the sonicated rMPC samples did increase but did not revert to the pre-sonicated values. Samples were also tested for free fatty acids (rancidity) sulfur compounds and pH. The pH values of sonicated samples were not statistically different from the non-sonicated samples. The free fatty acids values and sulfur compounds of the sonicated samples were higher than the control, this analysis is being repeated to confirm the results.

Publications

  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Kareem, A. A., Shakir, K. A., & Walsh, M. K. (2018, September 20). Antioxidant Activities of Okra Protein Concentrate and Isolate after Enzymatic Hydrolysis. Food and Nutrition Sciences, 9, 1066-1077.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Lee, S.-M., Wagh, A., Sandhu, G., & Walsh, M. K. (2018, December). Emulsification properties of lactose fatty acid esters. Food and Nutrition Sciences, 9, 1341-1357.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Walsh, M. K., Khliaf, H.F., & Shakir, K.A. (2018, March). Production of xylitol from agricultural waste by enzymatic methods. Am. J. Ag. Biol. Sci, 13(1), 1-8.


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

Outputs
Target Audience:Food industry, food scientists, dairy processors Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?I participated in 4 conferences (regional and international) presenting my research. During the 2017 year, I trained 1 undergraduate student and 3 PhD students. How have the results been disseminated to communities of interest?I have 5 publications published in international peer-reviewed journals in 2017. I also presented the information related to this project at 2 international and 2 regional conference. What do you plan to do during the next reporting period to accomplish the goals?We will continue with the research outlined to complete objective 2.

Impacts
What was accomplished under these goals? We have continued research associated with objective 1 and initiated research associated with objective 2. We previously reported that an increase in solids content and a decrease in temperature lead to an increase in viscosity of reconstituted skim milk powder (rSMP) and reconstituted milk protein concentrate (rMPC). Additionally, there was a reduction in viscosity with the application of sonication in a batch system with rSMP at total solids (TS) contents ranging from 46 to 64% at temperatures of 40, 50 and 60 C. We investigated the influence of batch sonication on the viscosity of rMPC at solids contents of 30 to 44% at 40, 50 and 60 C. At 60 C, the decrease in viscosity ranged from 27 to 44% at TS ranging from 30 to 44%. At 50 C, the decrease in viscosity ranged from 37 to 55% at TS between 30 and 44%. At 40 C, we were unable to conduct experiments at TS greater than 36% TS due to samples being too viscous. At 40 C, the decrease in viscosity ranged from 28 to 51% at TS between 30 and 36%. An overall greater percentage decrease in viscosity due to batch sonication was seen with an increase in % TS for rMPC compared to rSMP. For rMPC, the % decrease in viscosity as a result of batch sonication was greater at 50 °C, followed by 40 then 60°C. We also conducted studies on the effects of sonication on the viscosity of rSMP using a flow through sonication system to simulate a continuous operation. rSMP samples were reconstituted to a 3 L volume at 50, 52 and 54% TS and pumped at a flow rate of 1.8 L/ min for a total of 15 min before being sonicated and a sample was collected at this time point. The sonication flow cell had a 261 mL volume resulting in a 8.4 sec residence time (time sample was exposed to sonication) for the 1.8 L/min flow rate. For flow through sonication, samples were recirculated through the system. Samples were collected for viscosity measurements at 2, 4, and 6 min, which corresponded to total sonication residence times of 10.1, 20.2, and 30.2 s. For the continuous operation, rSMP was sonicated at 90 % amplitude. Samples were recirculated through the flow through system post sonication and samples were collected for viscosity measurements at 45 min for rSMP. For rSMP, % TS of ≥54 % in a continuous system required long heating times to form a continuous solution which resulted in age gelation of samples, therefore the highest TS used was 54. A decrease in viscosity of 16, 38 and 42% was observed with a TS of 50% at residence times of 10.1, 20.2 and 30.2 sec. A decrease in viscosity of 6, 9 and 13% was observed with a TS of 52% and a decrease in viscosity of 2, 16 and 22% was observed at a TS of 54% at residence times of 10.1, 20.2, and 30.2 sec. Therefore, the application of sonication decreases the viscosity of concentrated milks and may be used to modulate the viscosity allowing higher solids going to the dryer, which would be an economical benefit to the dairy industry.

Publications

  • Type: Journal Articles Status: Published Year Published: 2017 Citation: C. N., Rahman, A., Rehman, A., Walsh, M. K., Miller, c. (2017). Food Waste Conversion to Microbial Polyhydroxyalkanoates. Microbial Biotechnology
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Nam, S.-h., Kim, Y.-M., Walsh, M. K., Wee, Y.-J., Yang, K.-Y., Ko, J.-A., Hanh, T. T., Kim, J. Y., KIm, D. (2017). Synthesis and Functional Characterization of Caffeic Acid Glucoside Using Leuconostoc mesenteroides Dextransucrase. Journal of Agricultural and Food Chemistry, 65(13), 2743-2750. DOI: 10.1021/acs.jafc.7b00344
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Nam, S.-h., Ko, J.-A., Y.-J. W., Walsh, M. K., Yang, K.-Y., Eun, J.-B., Jun, W., Park,, J.-H. (2017). Enzymatic synthesis of chlorogenic acid glycoside using dextransucrase and its physical and functional properties. Enzyme and Microbial Technology, 107, 15-21. https://doi.org/10.1016/j.enzmictec.2017.07.011
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Qasim, S., Shakir, K., Al-Shaibani, A.B., Walsh, M. K. (2017). Optimization of culture conditions to produce phytase from Aspergillus tubingensis SKA. Food and Nutrition Sciences, 8, 733-745. 10.4236/fns.2017.87052
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Walsh, M. K., S.M L., Sanhdu, G. (2017). Growth inhibitory properties of lactose fatty acid esters. S. J. Biological Sci. DOI: 10.1016/j.sjbs.2015.10.013
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Walsh, M. K. (Author Only), Deshpande, V. (Presenter & Author), ADSA Annual Meeting, "Influence of sonication on the viscosity of reconstituted SMP & MPC.," American Dairy Science Association, Pittsburgh, PA. (June 2017)
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Walsh, M. K., Lee, S.-m. (Presenter & Author), American Association of Microbiology, "Anti-listerial Activity Of Lactose Esters In Milk," ASM Micro, New Orleans LA. (June 1, 2017 - June 5, 2017)
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Deshpande, V. (Presenter & Author), Walsh, M. K. (Author Only), Bonneville Section of IFT Food and Candy Expo, "Effect of batch sonication on the viscosity of reconstituted milk powders as influenced by total solids and temperature.," Bonneville Section of IFT, Salt Lake City Ut. (April 2017)
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Deshpande, V. (Presenter & Author), Walsh, M. K. (Author Only), USU Research Week, "Effect of Sonication on Viscosity of reconstituted SMP and MPC as influenced by solids content.," USU RGS, USU. (April 2017)


Progress 07/01/16 to 09/30/16

Outputs
Target Audience:Target Audience Food industry, food scientists, dairy processors Changes/Problems:Changes/Problems No changes or problems. What opportunities for training and professional development has the project provided?Opportunities I participated in one international and one regional food science conferences. I am training 3 graduate students (1 MS and 2 PhD) and 1 undergraduate student. How have the results been disseminated to communities of interest?Dissemination I have 4 publications published in international peer-reviewed journals in 2016. I also presented the information related to this project at one international and one regional conference. What do you plan to do during the next reporting period to accomplish the goals?Plan of Work We will continue with research on objective 1 and start research on objective 2 during the 2017 calendar year.

Impacts
What was accomplished under these goals? Accomplishments We have initiated research associated with objective 1. Milk Protein Concentrate was reconstituted to 30 to 44% solids (rMPC) and the viscosity was measured at temperatures ranging from 40 to 65 C. Skim Milk Protein concentrate was reconstituted to 46 to 64% solids (rSMP) and the viscosity was measured at temperatures ranging from 40 to 60 C. Overall, there was an increase in viscosity with an increase in solids content at each temperature tested for both rSMP and rMPC. The increase was exponential at 40 and 50 C in rSMP and was linear at 40, 50 and 60 C in rMPC. With rSMP, there was a 903.8 and 2012.6 % increase in viscosity at 50 and 40 C respectively compared to 60 C at 54% solids. With rMPC, there was a 900% and 2715% increase in viscosity at 50 and 40 C compared to 60 C at 34% solids. This shows the dramatic effect of temperature on the viscosity, with significantly higher viscosities at lower temperatures. We investigated the influence of sonication on the reduction of viscosity of concentrated rSMP. At 60 C, there was a reduction in viscosity of 19 to 40% at solids contents ranging from 46 to 64%. At 50 C there was a reduction in viscosity of 19 to 34% at solids contents ranging from 46 to 54%. At 40 C, there was a reduction in viscosity of 19 to 34% at solids contents ranging from 46 to 54%. Overall, the use of sonication significantly reduced the viscosity of concentrated rSMP, with higher reductions at 60 C compared to lower temperatures.

Publications

  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Nam, S.H., Walsh, M. K., Yang, K.Y. (2016). Comparison of four purification methods to purify cysteine protease from Asian pear fruit (Pyrus pyrifolia). Biocatalyst Agricultural Biotechnology, 5, 86-93.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Nam, S.-h., Kim, Y., Walsh, M. K., Yim, S.-H., Eun, J.-B. (2016). Functional characterization of purified pear protease and its proteolytic activities with casein and myofibrillar proteins. Food Science and Biotechnology, 25 S1, 31-39.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Nam, S.-h., Walsh, M. K., Kim, S.H., K.Y. Y. (2016). Identification and functional characterization of cysteine protease from nine pear cultivars (Pyrus pyrifolia). International Journal of Food Properties, 19, issue 7, 1631-1634.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Nam, S.-h., A. W., Martini, S., Walsh, M. K. (2016). Sensory characterization of a high protein beverage. International Journal of Dairy Technology.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: Presentations Lee, S.-m. (Presenter & Author), Walsh, M. K. (Author Only), Institute of Food Technologists Annual Meeting, "Emulsification Properties of Lactose Fatty Acid Esters," IFT, Chicago, IL. (July 2016 - Present)
  • Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: Presentations Deshpande, V. (Presenter Only), Walsh, M. K., BUILD Dairy, "Effects of sonication on the viscosity of concentrated skim milk and milk protein concentrate as influenced by solids content and temperature," Western Dairy Center, USU, Utah State University. (June 2016 - Present)