INNOVATIVE FOOD DEHYDRATION TECHNOLOGIES FOR IMPROVING PRODUCT QUALITY, ENERGY EFFICIENCY, AND SUSTAINABILITY

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: AFRI COMPETITIVE GRANT
• Reporting Frequency: Annual
• Accession No.: 1014736
• Grant No.: 2018-67017-27913
• Cumulative Award Amt.: $910,000.00
• Proposal No.: 2017-05022
• Project Start Date: May 1, 2018
• Project End Date: Apr 30, 2023
• Grant Year: 2018
• Program Code: [A1363]- Food Manufacturing Technologies

Recipient Organization
UNIVERSITY OF ILLINOIS
2001 S. Lincoln Ave.
URBANA,IL 61801

Performing Department
FSHN

Non Technical Summary
Drying is one of the most widely used food processing and preservation methods. It is also the most energy intensive unit operation due to the need to supply thermal energy to remove large amounts of water in food. More importantly, exposing food to elevated temperatures for a prolonged period is needed to produce shelf-stable product, which inevitably degrades food quality. This poses a grand challenge for engineers and food technologists to tackle these two interconnected drying problems. In this project, we propose to develop two innovative drying technologies (a novel ultrasonic contact drying method and innovative nozzle technologies)to achieve the dual goal of improving product quality and reducing production costs. Our proposed work will be the first such endeavor to develop ultrasonic contact drying and innovative impinging jets for food dehydration applications. Especially important is thatthe two technologies are complementary with regards to the target food products to be dried. The ultrasonic contact drying is suitable for applications for drying of liquid foods, purees, and fruit and vegetables slices, while the innovative nozzle can dry solid products of various shapes. Thus, these two new drying technologies cover a wide range of food products having an impact on the production of many food product sectors. The technologies envisioned in this project will be suited for a broad range of industrial drying, heating, and other applications. The generated scientific knowledge and engineering information will have long-term impacts on the food and agriculture industry, research community, and in the training and development of the next generation workforce.

Animal Health Component

40%

Research Effort Categories

Basic

30%

Applied

40%

Developmental

30%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
501	5010	2020	100%

Knowledge Area
501 - New and Improved Food Processing Technologies;

Subject Of Investigation
5010 - Food;

Field Of Science
2020 - Engineering;

Keywords

drying

contact drying

energy consumption

food quality

impinging jet

ultrasound

Goals / Objectives
The significant energy consumption and food quality degradation in drying require the devising of innovative food dehydration strategies. This project willexplore two innovative drying technologies (innovative impinging jet and ultrasonic contact drying) to achieve the dual goal of improving product quality and reducing production costs.

Project Methods
In Objective One, we will develop twonew nozzles (RJR and SJR)for the food industry sector (mainly drying of vegetables and fruits as well as drying and baking of snacks such as potato chips and cookies). We will start with the design of RJR and SJR nozzles under the corresponding operating conditions pertinent to the above-mentioned products, followed by modification of the existing stationary drying/baking experimental setup. Drying experiments will be performed using the stationary setup with carrot cube. In Objective Two, we will first develop a bench-top ultrasonic drying prototype with minimal non-vibration surface area based on the tests conducted with the 10-cell module. Piezo transducers at two frequencies will be driven by an amplifier working in continuous, burst, modulation, or sweep mode. During drying, a gentle room-temperature airflow parallel to the drying surface will be used to remove the moisture. Strawberry and apple slices will be dried at two frequencies. Selected fruit or vegetable slices will be test-dried with the ultrasonic contact dryer, using room-temperature air to remove the moisture. Afterwards, we will then develop a pilot scale ultrasonic contact drying system that will enable drying of large samples. In Objective Three, quality attributes of the food products dried with innovative strategies (impinging nozzle and ultrasonic drying) will be comparedto quality achieved with conventional approaches. The quality attributes that will be evaluated include color, rehydration capacity, soluble solids, ascorbic acid, carotenoid content, antioxidant capacity, and sensory evaluation. A storage study will be performed with dried products to examine quality retention of the samples dried with the new method. In Objective Five, an evaluation will be performed to estimate energy efficiency of the innovative strategies of nozzle and ultrasonic drying. Objective 5 is to disseminate knowledge via short-course, workshop, website, and on-site demonstrations to students, Alliance members, the food industry, and the public. In Objective Six, education activities throughout the project will help graduate students to become future leaders in academia and industry on food processing technologies.

Progress 05/01/18 to 04/30/23

Outputs
Target Audience:Food technologists, food manufacturers Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Two PhD students at the University of Illinois at Urbana-Champaign were involved in this project. The first PhD student, Ozan Kahraman is now a R&D Food Process Engineer at Applied Food Sciences. The second PhD student, Amir Malvandi is now an Assistant Professor at University of Illinois Urbana-Champaign. Two PhD students at the Worcester Polytechnic Institute were involved in this project. Mr. Milad Farzad at Worcester Polytechnic Institute has received his PhD degree in Mechanical Engineering at WPI in May 2021. Upon his graduation, he joined PepsiCo. A second PhD student, Mengqiao Yang, partially supported by this grant from the USDA, is now a Process Modeling Engineer at PPG. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? [1] An improved ultrasonic contact-drying (US-CD) prototype was developed and used to dry apples in comparison with hot-air drying. The ultrasonic-contact drying of the apple slices on the surface of the transducer box was significantly faster than drying them under the same air conditions without ultrasound. After 40 min of ultrasound-contact drying, the moisture content of the apple slices reached 2.45% (wet basis, wb) while that without ultrasound was still as high as 39.4% (wb). After 40 min, the moisture content of the apple slices dried with hot air at 72oC was 42% higher than that of those dried with ultrasound at 26-33oC. The antioxidant capacity and total phenol contents of the US-CD samples were significantly higher than those of the hot-air-dried slices. In the US-CD apple slices, the total color change and browning index were 2.59 and 48.63, respectively, while in the hot-air samples they were 6.93 and 64.59. The novel ultrasonic contact dryer (US-CD) developed provides a uniform vibration to remove moisture from a product at low temperatures. The ultrasonic system with a central frequency of 20 kHz and nominal power of 1,000 W is based on a novel technology called MMM (multi-frequency, multimode and modulated), which synchronously excites a large number of harmonics and sub-harmonics of an acoustic load to create a more uniform vibration. The US-CD drying was used for drying of selected plant foods, e.g. Gala apples under non-thermal conditions. The (US-CD) was performed in the presence of an air stream (26 to 40 oC) flowing over product surface to remove mist or vapor produced by the ultrasound treatment. The effects of the non-thermal US-CD, hot-air drying (HAD), and freeze drying (FD) on the changes in rehydration ratio, pH, titratable acidity, water activity, color, glass transition temperature, texture, antioxidant capacity, total phenols, and microstructures of the samples were evaluated. The moisture content of the apple slices reached below 5 % (w.b.) after 75-80 min of US-CD, which was about 45% less than that of the HAD method. The antioxidant capacity and total phenol contents of the US-CD samples were significantly higher than that of the AD samples. Energy consumption of ultrasonic drying has been calculated by two methods: a) using a power meter to calculate the active, reactive, apparent and complex water and b) theoretical modeling of energy consumption using active energy and the kinetics of drying. The MMM ultrasonic dryer was retrofitted by including more sensors for precise and accurate control and measurement of drying parameters. Four temperature and relative humidity sensors were added to the dryer for measurement of environmental variables and a variable speed motor was added to control the airspeed during drying. Real-time data acquisition and control system by NI myRio have been added to the dryer. A dehumidifier was added to the closed drying system to enable regulation of relative humidity during experiment. Preliminary data showed that ultrasonic drying would reduce the energy consumption by 32% and decrease the operating temperature from 54.4°C to 41.8°C for total drying time of 70 min. For step-wise optimization, the energy consumption was reduced further by about 40%. [2]Convective air-drying was performed with a commercial impingement oven retrofitted with slot jet reattachment (SJR) nozzles on apple slices, potato chips, and cookie dough. The samples were dried using SJR nozzles with exit angles of +20° and +45° or perforated plates, at various operating conditions. The drying tests on the apples were carried out with SJR nozzles with an exit angle of +20°. The tests were conducted with air temperatures at the nozzle exits of 120°C and 160°C and belt speeds of 0.125 to 0.5 m/min, respectively. Enhancements up to 8.5% were achieved using SJR+20o nozzles compared to perforated plates. The SJR+45° nozzles performed up to 17.3% better than the perforated plates. The next tests were done on the drying characteristics of cookie dough with SJR nozzles using an exit angle of +45°. The air temperatures at the nozzle exits were 150oC, 150oC, and 205oC, and the belt speeds were 0.33 m/min, 0.17 m/min, and 0.33 m/min, respectively. Enhancements of 34.2%, 34.2%, and 43.8% were achieved under the above-mentioned conditions, respectively, using SJR+45o nozzles compared to perforated plates. In all drying tests with SJR jets, significant enhancements were achieved in the drying rates.These significant enhancements make the SJR nozzle technology ideal for improving the thermal performance of existing or new ovens. Experiments were performed with the slot jet reattachment (SJR) nozzles to evaluate drying performance with cookie dough, potato chip, carrot, and strawberry samples. To analyze the performance of perforated plates and SJR nozzles, heat flux and temperature measurements were performed, using a custom-made sensor traveling through the oven. The experiments with cookie dough were conducted at 150 to 205oC for 3 to 6 min. For potato chips, the drying tests were done at 120 to 150oC for 2-4 min. SJR drying of carrot and strawberry was performed at 120 to 150oC for 1 to 5 min.For potato chips, the highest drying enhancement was recorded for drying at 140oC for 2 min, with an oven belt velocity (Vb) of 0.5 m/min. The most efficient drying of carrots was observed at 135oC with an oven belt velocity of 0.33 m/min. The drying of strawberries can be enhanced by 8.7% to 24.6%, with the later achieved at 135oC and a Vb of 1 m/min. In terms of convection coefficient, for the SJR nozzles, the average outlet coefficient was 32.6% higher than the perforated plate that was used as a reference in the study. Together, the results showed that a significant improvement in drying with the use of the SJR+45° nozzle against perforated plate was achieved. In addition, in 2020-2021, the SJR nozzle technology was successfully retrofitted into a commercial scale pilot oven by a major food company. The results showed significant enhancements in drying rates with the SJR nozzle technology. A second major food company is currently retrofitting this technology into their pilot oven. This has been a major accomplishment as a full transfer of this technology is expected to take place in the next few years. In the final stage of the project, a pilot scale smart drying testbed that integrates slot jet (SJR) reattachment nozzle module, air-borne ultrasonic drying module, and electric field drying module into one test rig for the goal of developing AI-assisted optimization strategies. The testbed will be fabricated by Reading Bakery Systems, located at Reading Pennsylvania. We have finished the design of a pilot scale drying test bed and the testbed is scheduled to be delivered to Worcester Polytechnic Institute (WPI) in May 2022.The design of slot jet (SJR) reattachment nozzles to be retrofitted into the MMM ultrasonic non-thermal drying testbed at University of Illinois has been completed. The design of SJR nozzles to be retrofitted into the smart dryer testbed at WPI has been completed and submitted to Reading Bakery Systems Company to fabricate. Evaluation of SJR nozzles' drying performance at sub-pilot scale at WPI and on a commercial large scale pilot machine has been completed. Energy savings higher than the targeted goals have been achieved. We have also conducted numerical simulation of drying of pressed paper with low moisture content in the presence of ultrasound modules in some sections of multi-cylinder dryer section of paper machine. More tests on drying of fruits with slot jet reattachment nozzles were performed. The enhancements in drying rates with slot jet reattachment nozzles for select products, such as cookie dough were evaluated. Drying time reduction of up to 57% was achieved for the same peal pressure.

Publications

• Type: Journal Articles Status: Published Year Published: 2021 Citation: Malvandi A, Feng H, Kamruzzaman M. 2021. Application of NIR spectroscopy and multivariate analysis for non-destructive evaluation of apple moisture content during ultrasonic drying, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, https://doi.org/10.1016/j.saa.2021.120733
• Type: Journal Articles Status: Published Year Published: 2021 Citation: Vargas L, Kapoor R, Nemzer B, Feng H. 2021. Application of different drying methods for evaluation of phytochemical content and physical properties of broccoli, kale, and spinach, LWT Food Science and Technology, https://doi.org/10.1016/j.lwt.2021.112892.
• Type: Journal Articles Status: Published Year Published: 2021 Citation: Kapoor R, Malvandi A, Feng H, Kamruzzaman M. 2021. Real-time moisture monitoring of edible coated apple chips during hot air drying using miniature NIR spectroscopy and chemometrics, LWT Food Science and Technology, https://doi.org/10.1016/j.lwt.2021.112602.
• Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Kapoor R, Feng H. 2021. Characterization of physicochemical, thermal, microstructural and packing properties of blueberry, cranberry, beet, and carrot powders dried using different methods. Annual Meeting of the Institute of Food Technologists.
• Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Wang X, Kahraman O, Feng H. 2021. Impregnation-mediated natural fortification of sliced apples with hypertonic fruit juices: mass transfer kinetics and product quality. American Society of Agricultural and Biological Engineers Annual International Meeting.
• Type: Journal Articles Status: Published Year Published: 2021 Citation: Kahraman, O., Malvandi, A., Vargas, L., and Feng, H. 2021. Drying characteristics and quality attributes of apple slices dried by a non-thermal ultrasonic contact drying method, Ultrasonics Sonochemistry, 73, 105510. (https://doi.org/10.1016/j.ultsonch.2021.105510)
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Farzad, M., El Ferouali, H., Kahraman, O., and Yagoobi, J. 2020. Enhancement of heat transfer and product quality using jet reattachment nozzles in drying of food products, Drying Technology, (https://doi.org/10.1080/07373937.2020.1804927).
• Type: Journal Articles Status: Published Year Published: 2022 Citation: Malvandi A, Kapoor R, Feng H, Kamruzzaman M. 2022. Non-destructive measurement and real-time monitoring of apple hardness during ultrasonic contact drying via portable NIR spectroscopy and machine learning, Infrared Physics and Technology, 122, 104077, https://doi.org/10.1016/j.infrared.2022.104077.
• Type: Journal Articles Status: Published Year Published: 2022 Citation: Malvandi A, Coleman DN, Loor JJ, Feng H. 2022. A novel sub-pilot-scale direct-contact ultrasonic dehydration technology for sustainable production of distillers dried grains (DDG), Ultrasonics Sonochemistry, https://doi.org/10.1016/j.ultsonch.2022.105982.

Progress 05/01/21 to 04/30/22

Outputs
Target Audience:Members of the target audience included food technologists and food manufacturers. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Two PhD students at the University of Illinois at Urbana-Champaign are involved in this project. Mr. Milad Farzad at Worcester Polytechnic Institute has received his PhD degree in Mechanical Engineering at WPI in May 2021. Upon his graduation, he joined PepsiCo. A second PhD student, Mengqiao Yang, partially supported by this grant from the USDA, is expected to graduate in May of 2022. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals?In the next reporting period of this project, we will focus on combining slot jet reattachment (SJR) nozzle drying with the MMM non-thermal drying into the current MMM ultrasonic sub-pilot scale dryer. Design and fabrication of a retrofitted SJR jet test module will be completed and afterwards, fabricated and integrated into the MMM ultrasonic dryer. In addition, we will conduct a detailed energy analysis and optimization of the new integrated drying prototype.

Impacts
What was accomplished under these goals? The modulated, multimode, and multifrequency ultrasonic generation method was used to develop the non-thermal ultrasonic dryer. The MMM can produce a strong and uniform acoustic field on the drying surface, thus overcoming the nonuniform sound field issue in current ultrasound technology. Experiments have been conducted to develop a comprehensive model for US-CD drying for optimization and data-driven statistical modeling. Energy consumption of ultrasonic drying has been calculated by two methods: a) Using a power meter to calculate the active, reactive, apparent and complex water; and b) Theoretical modeling of energy consumption using active energy and the kinetics of drying. The MMM ultrasonic dryer was retrofitted by including more sensors for precise and accurate control and measurement of drying parameters. Four temperature and relative humidity sensors were added to the dryer for measurement of environmental variables and a variable speed motor was added to control the airspeed during drying. Real-time data acquisition and control system by NI myRio have been added to the dryer. A dehumidifier was added to the closed drying system to enable regulation of relative humidity during the experiment. Having this module added, the design and fabrication of sub-pilot scale MMM ultrasonic contact drying with the capacity to full adjust air velocity, temperature and relative humidity have been completed. An experiment design using response surface method (RSM) was completed, and a set of experiments have been performed to determine the interaction between control parameters including temperature, air velocity, ultrasonic amplitude, and ultrasonic pulse length and responses of interest, namely, energy consumption, color, and drying time. The interaction of variables and the equations are going to be used for multi-objective optimization of ultrasonic contact drying starting next quarter. Semi-empirical and thin layer drying models were developed for a variety of products including apple, zucchini and DDG and the equations were used for process optimization and step-wise optimization, respectively. Preliminary data showed that ultrasonic drying would reduce energy consumption by 32% and decrease the operating temperature from 54.4 degrees C to 41.8 degrees C for total drying time of 70 minutes. For step-wise optimization, the energy consumption was reduced further by about 40%. In this project period, one focus of the project was to develop a pilot scale smart drying testbed that integrates slot jet (SJR) reattachment nozzle module, air-borne ultrasonic drying module, and electric field drying module into one test rig for the goal of developing AI-assisted optimization strategies. The testbed will be fabricated by Reading Bakery Systems, located inReading, Pennsylvania. We have finished the design of a pilot scale drying test bed and the testbed is scheduled to be delivered to Worcester Polytechnic Institute (WPI) in May of 2022. In addition, a theoretical model is being developed to numerically determine the impact of contact and non-contact US mechanism on dehydration of moist porous media. This model will provide us with a physics-based tool to understand and analyze the data that will be obtained with sub-pilot scale US dryer as well as with the smart testbed. The design of slot jet (SJR) reattachment nozzles to be retrofitted into the MMM ultrasonic non-thermal drying testbed at the University of Illinois has been completed. The design of SJR nozzles to be retrofitted into the smart dryer testbed at WPI has been completed and submitted to Reading Bakery Systems Company to fabricate. Evaluation of SJR nozzles' drying performance at sub-pilot scale at WPI and on a commercial large scale pilot machine has been completed. Energy savings higher than the targeted goals have been achieved. We have also conducted numerical simulation of drying of pressed paper with low moisture content in the presence of ultrasound modules in some sections of multi-cylinder dryer section of paper machine. More tests on drying of fruits with slot jet reattachment nozzles were performed. The enhancements in drying rates with slot jet reattachment nozzles for select productssuch as cookie dough were evaluated. Drying time reduction of up to 57% was achieved for the same peal pressure.

Publications

• Type: Journal Articles Status: Published Year Published: 2021 Citation: Malvandi A, Feng H and Kamruzzaman M. 2021. Application of NIR spectroscopy and multivariate analysis for non-destructive evaluation of apple moisture content during ultrasonic drying, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, https://doi.org/10.1016/j.saa.2021.120733.
• Type: Journal Articles Status: Published Year Published: 2021 Citation: Vargas L, Kapoor R, Nemzer B and Feng H. 2021. Application of different drying methods for evaluation of phytochemical content and physical properties of broccoli, kale, and spinach, LWT Food Science and Technology, https://doi.org/10.1016/j.lwt.2021.112892.
• Type: Journal Articles Status: Published Year Published: 2021 Citation: Kapoor R, Malvandi A, Feng H and Kamruzzaman M. 2021. Real-time moisture monitoring of edible coated apple chips during hot air drying using miniature NIR spectroscopy and chemometrics, LWT Food Science and Technology, https://doi.org/10.1016/j.lwt.2021.112602.
• Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Wang X, Kahraman O and Feng H. 2021. Impregnation-mediated natural fortification of sliced apples with hypertonic fruit juices: Mass transfer kinetics and product quality. American Society of Agricultural and Biological Engineers Annual International Meeting.

Progress 05/01/20 to 04/30/21

Outputs
Target Audience:Members of the target audience included food technologists andfood manufacturers. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?One PhD student at the University of Illinois at Urbana-Champaign is involved in this project. Mr. Milad Farzad received his PhD degree in Mechanical Engineering at WPI in May 2021. Upon his graduation, he joined PepsiCo. A second PhD student, Mengqiao Yang, partially supported by this grant from the USDA, is expected to graduate in May 2022. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals?In the next reporting period of this project, we will focus on chemical and physical qualities of ultrasonic dried products and compareit with conventional drying methods such as freeze drying and hot air drying. The pilot scale dryer is going to be optimized to enhance the final product quality, nutrients and drying performance. In addition, we will conduct detailed computational work to understand the enhancements with SJR nozzle against perforated plate in drying of moist porous material.

Impacts
What was accomplished under these goals? The novel ultrasonic contact dryer (US-CD) developed provides a uniform vibration to remove moisture from a product at low temperatures. The ultrasonic system hasa central frequency of 20 kHz and nominal power of 1,000 W and is based on a novel technology called MMM (multi-frequency, multimode and modulated), which synchronously excites a large number of harmonics and sub-harmonics of an acoustic load to create a more uniform vibration. The US-CD drying was used for drying of selected plant foods, e.g. Gala apples under non-thermal conditions. The (US-CD) was performed in the presence of an air stream (26 to 40 degreesC) flowing over product surface to remove mist or vapor produced by the ultrasound treatment. The effects of the non-thermal US-CD, hot-air drying (HAD), and freeze drying (FD) on the changes in rehydration ratio, pH, titratable acidity, water activity, color, glass transition temperature, texture, antioxidant capacity, total phenols, and microstructures of the samples were evaluated. The moisture content of the apple slices reached below 5 % (w.b.) after 75-80 minutes of US-CD, which was about 45% less than that of the HAD method. The antioxidant capacity and total phenol contents of the US-CD samples were significantly higher than that of the AD samples. US-CD drying was also used to dry wet distiller's grain with solubles (WDGS). The WDGS was made into a flat sheet on the top surface of a MMM ultrasound-driven vibrating plate by a hand-roller. The WDGS sheet having a thickness of twomm was cut into small circular sub-samples with a fifteenmm diameter. Drying was performed at 25, 50, and 70 degrees C with and without ultrasound (US) with an air velocity of 1.5 m/s. Wet chemistry analysis was performed by a commercial lab, including available protein, indigestible protein, and fiber. Color was monitored via a reflectance colorimeter (LabScan XE) based on the CIE L*, a*, and b* color space. Results showed that application of ultrasound (US) significantly enhanced the drying rate, especially in the early stage of drying. At 25 degrees C, for instance, the initial drying rate increased nearly 3.5 times, from 0.063 per minute(without US) to 0.216 per minute (with US). With a final moisture content of 6 to 7% (wet basis) as the goal, the presence of ultrasound reduced drying time by 52%, 47%, and 40% for air temperatures of 25, 50, and 70 degrees C, respectively. Ultrasonic drying under a nonthermal condition (25 degrees C) led to a similar drying time as did hot air (HA) drying at 70 degrees C, indicating that ultrasonic drying is a suitable alternative to thermal drying in the production of DDGS. Ultrasonic drying increased the effective moisture diffusivity by 164%, 150% and 32% for air temperatures of 25, 50, and 70 degrees C, respectively. The final DDGS processed by the ultrasonic drying at 25 degrees C had an improved brightness of 80.2 and reduced total color change of 16.6 compared with 75.5 and 21.12 for HA drying, respectively. The ultrasonic drying at 25 degrees C increased crude protein content from 43% and 44% for HA70 (HA drying at 70 degrees C) and HA50 (HA drying at 50 degrees C), respectively, to 46% for US25 (US drying at 25 degrees C). It also reduced ADICP (Acid detergent insoluble crude protein) from 9.7% and 8.5% for HA70 and HA50 respectively to 6% for US25. The outcomes demonstrated that US drying decreased drying time and temperature during DDGS production while it improved the final product with a lighter color and higher digestible crude protein content. The non-thermal ultrasonic contact drying is a promising method which has the potential to significantly reduce drying time and improve product quality. Experiments were performed with the slot jet reattachment (SJR) nozzles to evaluate drying performance with cookie dough, potato chip, carrot, and strawberry samples. To analyze the performance of perforated plates and SJR nozzles, heat flux and temperature measurements were performed, using a custom-made sensor traveling through the oven. The experiments with cookie dough were conducted at 150 to 205 degreesC for three to six minutes. For potato chips, the drying tests were done at 120 to 150 degreesC for two to four minutes. SJR drying of carrot and strawberry was performed at 120 to 150 degreesC for one to five. A drying enhancement of 34.2% to 43.8% was achieved in drying of cookie dough and the highest enhancement was observed for the drying test at 205 degreesC. The "enhancement" refers to the higher moisture loss with the SJR nozzle compared to those of perforated plate. For potato chips, the highest drying enhancement was recorded for drying at 140 degreesC for 2 minutes, with an oven belt velocity (Vb) of 0.5 m/minute. The most efficient drying of carrots was observed at 135 degreesC with an oven belt velocity of 0.33 m/minute. The drying of strawberries can be enhanced by 8.7% to 24.6%, with the later achieved at 135 degreesC and a Vb of 1 m/minute. In terms of convection coefficient, for the SJR nozzles, the average outlet coefficient was 32.6% higher than the perforated plate that was used as a reference in the study. Together, the results showed that a significant improvement in drying with the use of the SJR+45° nozzle against perforated plate was achieved. In addition, in 2020-2021, the SJR nozzle technology was successfully retrofitted into a commercial scale pilot oven by a major food company. The results showed significant enhancements in drying rates with the SJR nozzle technology. A second major food company is currently retrofitting this technology into their pilot oven. This has been a major accomplishment as a full transfer of this technology is expected to take place in the next few years.

Publications

• Type: Journal Articles Status: Published Year Published: 2020 Citation: Kahraman, O., Malvandi, A., Vargas, L. and Feng, H. 2021. Drying characteristics and quality attributes of apple slices dried by a non-thermal ultrasonic contact drying method. Ultrasonics Sonochemistry, 73, 105510. (https://doi.org/10.1016/j.ultsonch.2021.105510).
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Farzad, M., El Ferouali, H., Kahraman, O. and Yagoobi, J. 2020. Enhancement of heat transfer and product quality using jet reattachment nozzles in drying of food products, Drying Technology, (https://doi.org/10.1080/07373937.2020.1804927).
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2020 Citation: Farzad, M. and Yagoobi, J. 2022. Enhancement of drying of food products with slot jet reattachment nozzles in a convective oven with a moving belt. International Drying Symposium, Worcester, MA (IDS2020 postponed due to pandemic, accepted).
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2020 Citation: Kahraman, O., Malvandi, A. and Feng, H. 2022. Drying kinetics of sliced strawberries using a novel ultrasonic contact dryer. 22nd International Drying Symposium, International Drying Symposium, Worcester, MA, June 2022 (IDS2020 postponed due to pandemic, accepted).
• Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Malvandi, A. and Feng, H. 2021. Drying of distillers dried grains with solubles (DDGS) with a nonthermal ultrasonic contact drying method: Drying kinetics and product quality. ASABE 2021, AIM 2021 Poster Session.
• Type: Theses/Dissertations Status: Published Year Published: 2021 Citation: Farzad, M. 2021. Enhancement of heat and mass transfer using jet reattachment nozzles over stationary and moving surfaces  Experimental and numerical study. PhD dissertation, Worcester Polytechnic Institute, May 2021.

Progress 05/01/19 to 04/30/20

Outputs
Target Audience:Members of the target audience included food technologists andfood manufacturers. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?One PhD student at the University of Illinois at Urbana-Champaign is involved in ultrasonic-drying prototype development and drying-kinetics analysis, and another PhD student from Worcester Polytechnic Institute is working on the development of a novel jet-reattachment-nozzle drying method. One UIUC graduate student (Dana Dubinski) did her master's thesis on analyzing the quality of US-CD-dried apple slices. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals?In Year 3 of this project, we will further develop a moving-belt drying system with the new RJR and SJR nozzle technologies for drying food products. In ultrasonic drying-technology development, we will develop a sub-pilot-scale ultrasonic drying unit for drying selected products. The quality of products dried with ultrasound and the new RJR and SJR nozzle dryers will be evaluated, including physical and chemical analyses. In addition, we will evaluate the energy efficiency of the impinging-jet and ultrasonic-contact drying systems.

Impacts
What was accomplished under these goals? An improved ultrasonic contact-drying (US-CD) prototype was developed and used to dry apples in comparison with hot-air drying. For non-thermal US-CD, a 40 kHz, 1-kW ultrasonic transducer box (400')convective air-drying was performed with a commercial impingement oven retrofitted with slot jet reattachment (SJR) nozzles on apple slices, potato chips, and cookie dough. The samples were dried using SJR nozzles with exit angles of +20° and +45° or perforated plates, at various operating conditions. All comparisons were made based on the identical fluid-flow power criterion, which is the worst-case comparison scenario for SJR nozzles. Under this criterion, the flow rate for SJR nozzles is significantly lower than that of the perforated plates, due to the additional pressure drop associated with the SJR nozzles. The drying tests on the apples were carried out with SJR nozzles with an exit angle of +20°. The tests were conducted with air temperatures at the nozzle exits of 120°C and 160°C and belt speeds of 0.125 to 0.5 m/minute, respectively. Enhancements up to 8.5% were achieved using SJR+20o nozzles compared to perforated plates. Next, the drying characteristics of potato chip samples dried by SJR nozzles with an exit angle of +45° were investigated. The tests were conducted with air temperatures at the nozzle exits of 120°C, 130°C, and 140°C, and corresponding belt speeds of 0.125 m/minute, 0.33 m/minute, and 0.5 m/minute. The SJR+45° nozzles performed up to 17.3% better than the perforated plates. The next tests were done on the drying characteristics of cookie dough with SJR nozzles using an exit angle of +45°. The air temperatures at the nozzle exits were 150oC, 150oC, and 205oC, and the belt speeds were 0.33 m/minute, 0.17 m/minute, and 0.33 m/minute, respectively. Enhancements of 34.2%, 34.2%, and 43.8% were achieved under the above-mentioned conditions, respectively, using SJR+45o nozzles compared to perforated plates. In all drying tests with SJR jets, significant enhancements were achieved in the drying rates. Much higher enhancements can be achieved if the comparison criterion is changed to identical exerted pressure or mass flow rate. These significant enhancements make the SJR nozzle technology ideal for improving the thermal performance of existing or new ovens.

Publications

• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Kahraman O., Malvandi A. and Feng H. 2019. Drying kinetics and quality attributes of apple slices dried with a non-thermal ultrasound drying method. 2019 Annual International Meeting, American Society of Agricultural and Biological Engineers, Boston, MA.
• Type: Journal Articles Status: Submitted Year Published: 2020 Citation: Farzad M., Ferouali H., Yagoobi J. and Ramsay S. 2020. Enhancement of heat transfer and product quality using jet reattachment nozzles in drying of food products. Drying Technology (Submitted).

Progress 05/01/18 to 04/30/19

Outputs
Target Audience:Members of the target audience included food technologists and food manufacturers. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?One PhD student on this project is involved in ultrasonic-drying prototype development and drying kinetics analysis. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals?In Year Twoof this project, we will evaluate the energy consumption of the new ultrasonic contact-drying method in comparison with hot-air drying. A sub-pilot-scale ultrasonic-contact drying unit will be developed and tested.

Impacts
What was accomplished under these goals? In Year Oneof this project, a novel use of power ultrasound was explored for drying apple slices with no or minimal application of heat. An ultrasonic contact-drying (US-CD) prototype was first developed. The US-CD of the apple slices was performed with an air stream (26 to 40 degreesC) flowing over the product surfaces to remove mist and/or vapors produced during drying. The effects of the non-thermal US-CD, hot-air drying (AD), and freeze drying (FD) on the drying kinetics, rehydration ratio, pH, titratable acidity, water activity, color, glass transition temperature, texture, antioxidant capacity, total phenols, and microstructures of the samples were evaluated. The moisture content of the apple slices was reduced to below 5% (wet basis) after 75-80 minutes of US-CD, which was 80% less than that of the AD method. The best quality retention was achieved with the FD method. The antioxidant capacity and total phenol content of the US-CD samples were significantly higher than those of the AD samples. Ultrasonic contact drying is thus a promising method for significantly reducing drying time and improving product quality.

Publications