DEVELOPMENT OF GREEN, REUSABLE, AND SELF-CLEANABLE “ICE” CUBES TO REDUCE TEMPERATURE ABUSE IN COLD CHAIN

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: EXTENDED
• Funding Source: AFRI COMPETITIVE GRANT
• Reporting Frequency: Annual
• Accession No.: 1022119
• Grant No.: 2020-67017-31275
• Project No.: CA-D-FST-2581-CG
• Proposal No.: 2019-06757
• Program Code: A1364
• Project Start Date: Jun 1, 2020
• Project End Date: May 31, 2024
• Grant Year: 2020

Project Director
Wang, L.

Recipient Organization
UNIVERSITY OF CALIFORNIA, DAVIS
410 MRAK HALL
DAVIS,CA 95616-8671

Performing Department
Food Science & Technology

Non Technical Summary
Temperature changes or abuses in food cold chains lead to compromised food safety and quality loss. In recent years, although different antimicrobial ice and reusable ice packs have been developed, drawbacks associated with these products, including the off-flavor caused with some antimicrobial ice and the safety concerns associated with reusable ice packs, prevent wide application of these products in the cold chain. New temperature control tools that can overcome these drawbacks are urgently needed. To address this need, the goal of this proposal is to develop green, reusable, and self-cleanable functional "ICE" cubes using plant-based by-products to facilitate the temperature control at the retail and consumer level. This "ICE" is made with soy protein isolate. A series of chemical and physical treatments will be applied to the soy protein before they are used for preparing the hydrogel. These chemical and physical treatments will not only enhance the processability of the soy protein but also reduce its allergenicity. To ensure the safety of re-using hydrogel "ICE", vitamin K compounds, natural compounds with bacteria killing properties, will be added into the re-usable "ICE". By doing so, these hydrogel "ICE" will not get moldy after repeated uses and will not become a cross-contamination vehicle. Once we manufacture this reusable and self-cleanable "ICE", we will test its antimicrobial efficacy, its temperature control capacity and re-usability by conducting shelf life experiments using seafood as the module products. We expect the product we develop here will significant benefit the cold chain, the consumers and the retailers.

Animal Health Component

0%

Research Effort Categories

Basic

40%

Applied

40%

Developmental

20%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
712	0810	1102	10%
503	0811	1100	30%
501	0810	2000	30%
712	0811	2020	30%

Knowledge Area
712 - Protect Food from Contamination by Pathogenic Microorganisms, Parasites, and Naturally Occurring Toxins; 501 - New and Improved Food Processing Technologies; 503 - Quality Maintenance in Storing and Marketing Food Products;

Subject Of Investigation
0810 - Finfish; 0811 - Shellfish;

Field Of Science
2020 - Engineering; 1102 - Mycology; 1100 - Bacteriology; 2000 - Chemistry;

Keywords

food loss and waste

ice

hydrogel

self-cleanable

soy protein isolate

vitamin k

Goals / Objectives
Temperature changes or abuses in food cold chains lead to compromised food safety and quality loss. Based on the currently available literature, temperature abuses at the retail and consumer levels are more frequent and significant compared to other steps involved in the cold chain. Among all contributing factors in foodborne outbreaks, temperature misuse ranked Top 1. In the United States, approximately 12% of food waste is caused by inappropriate refrigeration. To control temperature at the retail or consumer level, flaked ice or ice slurries have been widely used for perishable foods during transportation and retail displays. In recent years, essential oil supplemented ice or ice slurries as well as ice made with acidic electrolyzed water (AEW) had been developed. While this antimicrobial ice demonstrated effective control over pathogens and spoilage microorganisms, there are several hurdles hindering the use and adoption of the antimicrobial ice. These drawbacks include: 1, smell and off-flavor of essential oil after exposing to light and oxygen; and 2, the melting of ice causes physical and chemical damage to food quality (e.g. the pH of AEW ice is pH 2.3). Unless these concerns are addressed, antimicrobial ice products would not be widely adopted. At the consumer's level, reusable ice packs have also been used for a long time. These reusable ice packs come in different shapes and colors. Since they are reusable, these ice packs are considered very economically friendly. However, there are concerns associated with reusable icepacks. Among them, the cross-contamination caused by reusable ice packs or food containers has been the major one if cleaning and sanitizing are not done properly. Until now, packaged ice remained the top temperature control tool used by retail stores and consumers. The safety of packaged ice has received increasing attentions. In a recent study, the microbial quality of 250 bags of packaged ice, which were purchased from retail locations and self-service ice vending machines in Georgia were evaluated. Based on the results, 6% of the ice samples contained unsatisfactory levels of heterotrophs and 37% of these samples contained unsatisfactory levels of coliforms. One sample even tested positive for Salmonella.As described above, temperature abuse at the retail display and consumer levels is one important cause of food loss and waste. Although ice, antimicrobial ice, and reusable ice packs have been developed, drawbacks associated with these products prevented the further improvement of temperature control at the retail and consumer level. New temperature control tools that can overcome these drawbacks are urgently needed. To address this need, the goal of this proposal is to develop green, reusable, and self-cleanable functional "ICE" cubes using plant-based by-products to facilitate the temperature control at the retail and consumer level. There are three objectives of this proposal:Manufacturing soy protein isolate-based hydrogel "ICE" cubes with desired durability and reusability;Preparation of self-cleaning hydrogel "ICE" cubes with incorporation of photo-active vitamin K derivatives and controlled release of biocidal reactive oxygen species in the hydrogels;Evaluate the impact of the newly developed "ICE" on food quality by using seafood as model products.

Project Methods
There are three objectives this proposal will achieve. Here are summary of the experimental design for each objective.Objective 1. Manufacturing soy protein isolate (SPI) hydrogel "ICE" cubes produced from soy proteins with desired durability and reusabilityOverall experimental design: The goal of objective 1 is to design and develop a type of hydrogel "ICE" material using SPI as a major natural based component. Hydrophilic polymers such as poly(vinyl alcohol) (PVA), gelatin, alginate, and small protein molecules can form hydrogel structures by themselves or in a mixture form. For large and complicated protein structures like SPI, additional treatments and research are planned in objective 1 in order to make hydrogels like the one made with small protein molecules. We will optimize SPI treatment methods for making SPI hydrogel "ICE" with desired durability and reusability. Briefly, poly (vinyl alcohol) will still be employed for making hydrogels. The freezing-thawing method will serve as the process to physically crosslink the polymers and result in formation of SPI/PVA hydrogels. Further, soy protein will be enzymatically hydrolyzed to become smaller water-soluble molecules, and other food-safe polymers with good hydrophilicity will be tested and incorporated with SPI to make hydrogel "ICE" with better physical properties and ice performance for repeated applications. Meanwhile, chemical crosslinking methods will be used to ensure the stability and recyclability of designed "ICE" cubes. The cost of making the SPI hydrogel ICE will be calculated and analyzed. In order to minimize the cost of making SPI hydrogel ICE, the team will continuously explore the addition and use of other low cost materials during the preparation and manufacturing of SPI hydrogel ICE.Expected outcomes. It is expected that the final hydrogel "ICE" cube will have stable water-retaining property, good thermal-transferring ability at around 0°C, elastic mechanical properties, and multiple-time-of-use stability. It is food-use safe and environmentally friendly.Objective 2. Preparation of self-cleaning hydrogel "ICE" cubes with incorporation of photo-active vitamin K (VK) derivatives/compounds and controlled release of biocidal reactive oxygen species in the hydrogelsOverall experimental design: The goal of objective 2 is to evaluate the minimum bactericidal concentration (MBC) of different VK compounds by using both pathogenic and spoilage bacteria and prepare hydrogels with photo-induced antimicrobial functions. The MBC values will be determined under different light sources and at freezing and refrigeration temperatures. The MBC value determined will be added into ICE and the self-cleaning properties of VK-ICE will be investigated by artificially contaminating the VK-ICE with pure cultures and inoculated seafood juice. How light exposure can enhance the self-cleaning efficacy and recharging ability of the VK antimicrobial properties will also be evaluated.Expected result. It is expected that the MBC values of VK compounds for different bacterial strains will be different. We also expect to see lower MBC values under sunlight compared to regular room light. In the end, by comparing all MBC values, the highest MBC value of VK will be selected as the end VK level that needs to be added to "ICE". VK-SPI "ICE" is expected to have good self-cleaning efficacy. The self-cleaning efficacy can be negatively impacted by the presence of seafood juice. However, the use of light exposure is expected to help overcoming negative impacts generated by seafood juice on the self-cleaning efficacy of "ICE". Objective 3. Evaluate the impact of "ICE" on food quality by using seafood as model products Overall experimental design: Two types of seafood models will be used to evaluate the impact of VK-SPI "ICE" on food quality. A display-storage cycle will be designed to mimic the display and storage conditions used in retail stores. The two seafoods are oysters and salmon filets. Their microbial quality and their overall texture changes will be evaluated. Regular ice purchased from a local grocery store will be used as the control. Expected result. It is expected that VK-SPI "ICE" will preserve the seafood quality better than regular ice. Physical and chemical properties of "ICE" will not change during and after repeated uses.The team plans to present the research findings not only at different scientific meetings but also at various food sustainability and food waste management meetings. In this case, we will reach to maximum numbers of consumers, retailers and other stakeholders. We will be able to get their input in this product development as well as obtain their attention in cold chain management.

Progress 06/01/22 to 05/31/23

Outputs
Target Audience:During this report period, the team worked on the analysis of the mechanisms of gelatin-based hydrogels. In addition, the team has been working with commercial companies to further explore the opportunity of commercialization of the proposed jelly ice cubes. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?One postdoctoral researcher is funded by this project. How have the results been disseminated to communities of interest?One manuscript summarizing the new findings has been submitted to the Advanced Functional Materials. What do you plan to do during the next reporting period to accomplish the goals?We will complete objective 3.

Impacts
What was accomplished under these goals? There are three objectives of this project: 1.Manufacturing SPI hydrogel "ICE" cubes with desired durability and reusability; 2. Incorporating VK compounds into "ICE" and test the self-cleaning efficacy of "ICE" under different light sources at different temperatures; and 3.Evaluate the impact of "ICE" on food quality by using seafood as the model products. During this project reporting period, both objectives 1 and 2 have been completed. The team is currently working on Objective 3.

Publications

• Type: Journal Articles Status: Submitted Year Published: 2023 Citation: Zou, J., Wang, L., and Sun, G. 2023. Mechanisms and performances of physically and chemically crosslinked gelatin-based hydrogels as advanced sustainable and reusable "Jully Ice Cubes" coolant. Advanced Functional Materials.

Progress 06/01/21 to 05/31/22

Outputs
Target Audience:During this project period, the development of Jelly Ice Cube received a great amount of attention from the industry and the public. The story was first reported by the UC Davis and then local media in November 2021. Since then, stories covering the development has been published in different languages in more than 19 countries, including the United Kingdom, Germany, the Netherlands, New Zealand, Indonesia, Brazil, India, Switzerland, Italy, Australia, France, Canada, China, Korea, Singapore, Indonesia, Egypt, Korea, and Argentina. Inside US, the story was covered by major medias including but not limited to CBS, FOX, ABC and NPR. A provisional patent (Tech ID: 32532 / UC Case 2021-914-0) has been filed by the Regents of University of California in July 2021 and an official patent was filed in April 2022. As of July 2022, 20 Confidential Disclosure Agreements have been signed between the UC Davis Intellectual Property Office and various companies. Among them, 10 are from the U.S., 3 from Germany, 2 from Canada, 2 from Australia, 1 from Guatemala, 1 from Spain, and 1 from Israel. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Two graduate students are trained under this project. How have the results been disseminated to communities of interest?Three publications have been published during this period to distribute information to the scientific field, including 2 articles published in ACS Sustainable Chemistry & Engineering (cover article), and 1 article in Advanced Functional Materials. In addition, 2 Poster presentations and 1 oral presentation were delivered in the ACS National Conferences. Stories covering the development of jelly ice cube has been published in different languages in more than 19 countries, including the United Kingdom, Germany, the Netherlands, New Zealand, Indonesia, Brazil, India, Switzerland, Italy, Australia, France, Canada, China, Korea, Singapore, Indonesia, Egypt, Korea, and Argentina. Inside US, the story was covered by major medias including but not limited to CBS, FOX, ABC and NPR. What do you plan to do during the next reporting period to accomplish the goals?The team is on the right track for completing objective 3 by the end of next project report period.

Impacts
What was accomplished under these goals? There are three objectives of this project: 1.Manufacturing SPI hydrogel "ICE" cubes with desired durability and reusability; 2. Incorporating VK compounds into "ICE" and test the self-cleaning efficacy of "ICE" under different light sources at different temperatures; and 3. Evaluate the impact of "ICE" on food quality by using seafood as the model products. During this project reporting period, both objectives 1 and 2 have been completed. Three papers and one patent were generated from these two objectives. Objective 3 is ongoing and is expected to be completed by the end of project period.

Publications

• Type: Journal Articles Status: Published Year Published: 2021 Citation: Zou, J., Sbodio, A., Blanco-Ulate, B., Wang, L., and Sun, G. 2022. Novel robust, reusable, microbial-resistant, and compostable protein-based cooling media. Advanced Functional Materials. 32(26), 2201347. Zou, J., Wang, L., and Sun, G. 2021. Sustainable and reusable gelatin-based hydrogel "jelly ice cubes" as food collant. II: Ideal freeze-thaw conditions. ACS Sustainable Chemistry & Engineering. 9(46), 15365-15374. Zou, J., Wang, L., and Sun, G. 2021. Sustainable and reusable gelatin-based hydrogel "jelly ice cubes" as food coolant. I: feasibilities and challenges. ACS Sustainable Chemistry & Engineering. 9, 15357-15364.

Progress 06/01/20 to 05/31/21

Outputs
Target Audience: Nothing Reported Changes/Problems:The major challenge during this period was the Covid-19 global pandemic. Laboratory work density was reduced to decrease transmission risk and traveling within counties was restricted. A strategy of staggering work shifts implemented in PD and co-PD's Labs allowed work shifts both early and late hours thus reducing lab density. What opportunities for training and professional development has the project provided?Two graduate students are trained under this project. 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 year, soy protein will be further processed with the goal of making ice cubes with desired cooling efficacy. In addition, antimicrobial effects of different natural compounds will be tested and will be incorporated into ice cubes. Their control over both spoilage and pathogenic bacteria will be tested.

Impacts
What was accomplished under these goals? During this period of time, research has been carried out to process soy proteins with a combination of mechanical forces and other factors. By doing so, soy protein is better positioned for the manufacturing of ice cubes.

Publications

• Type: Journal Articles Status: Published Year Published: 2021 Citation: J Zou, NTH Nguyen, MD Biers, G Sun, Improved Processability of Soy Proteins Due to Conformational Controls under a Combination of Chemical and Mechanical Treatments, ACS Agricultural Science & Technology, 2021, 1(1) p11-20.