Source: NORTH CAROLINA A&T STATE UNIV submitted to
SAFETY AND SENSORY EVALUATIONS OF BABY SPINACH LEAVES PACKED IN BIO-NANOCOMPOSITES
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
1003261
Grant No.
(N/A)
Project No.
NC.X-290-5-15-170-1
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Oct 1, 2014
Project End Date
Sep 30, 2017
Grant Year
(N/A)
Project Director
Tahergorabi, RE, .
Recipient Organization
NORTH CAROLINA A&T STATE UNIV
1601 EAST MARKET STREET
GREENSBORO,NC 27411
Performing Department
Family and Consumer Sciences
Non Technical Summary
Baby spinach leaves as a ready-to-eat fresh produce is responsible for one third of foodborne illnesses. Commercially processed baby spinach leaves are currently packaged with perforated films. This practice raises a food safety concern that human pathogenic bacteria may transfer through the perforations and result in contamination of the produce. Thereby, it is essential that a packaging system be developed to improve the safety, as well as to maintain the sensory properties of fresh-cut baby spinach. The proposed research will address objectives 6 and 8 of the USDA-NIFA NCSU and NCA&T combined research initiatives which highlight "processing for food safety and fresh produce safety" and "human health, nutrition and well-being" respectively by developing a novel biodegradable, low-cost, and broadly effective nanocomposite packaging film that maintains the sensory properties and provide long lasting protection against pathogens throughout the distribution of baby spinach leaves. The biodegradable nanocomposite (bio-nanocomposite) film will be obtained by incorporating various concentrations of thyme essential oil into the film formulations prepared from sweet potato starch and montmorillonite nanoclays. The study will be conducted in two main parts. The first part will be developing the best possible bio-nanocomposite film and characterize its mechanical properties. In the second part, sensory properties of baby spinach leaves packed in the film and antibacterial effect of the film on inoculated baby spinach leaves against Salmonella spp. Listeria innocua and E. coli during refrigerated storage will be periodically evaluated.
Animal Health Component
0%
Research Effort Categories
Basic
100%
Applied
(N/A)
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
5011430110050%
5021450201025%
7124010309025%
Goals / Objectives
The long-range goal of this project is to develop bio-nanocomposite films that can successfully be used in packaging of fresh produce. The overall objective of this researchis to develop biodegradable nanocomposite-based food packaging films which incorporate thyme EO and biodegradable MMT nanofillers with SPS to address issues of food safety, environmental impact, and agricultural sustainability. The specific objectives of the proposed research are to: Objective 1: Develop biodegradable MMT nanocomposite films with SPS by incorporating thyme EO; Objective 2: Evaluate the physico-mechanical characteristics of the films; Objective 3: Investigate the antibacterial activity of the films on inoculated baby spinach leaves; Objective 4: Sensory evaluation of baby spinach leaves during storage at refrigerated temperature.
Project Methods
The study will be conducted in two main parts. The first phase will be developing the bio-nanocomposite films and characterize their mechanical properties (film thickness, water vapor permeability, tensile strength, color, transmission electron microscopy, and oxygen permeability). In the second phase, antibacterial effect of the developed novel film on the growth and survival of E. coil K-12 (a surrogate of E. coli O157:H7), Listeria innocua (a surrogate of Listeria monocytogenes), Salmonella Enteriditis and Salmonella Typhimurium inoculated on baby spinach leaves during refrigerated storage will be investigated. In addition, sensorial attributes (vegetable aroma, off-odor, color, browning, texture, and overall acceptability) of baby spinach leaves packed in the films will be studied as well.6.1. Sample preparation: Fresh packaged baby spinach leaves will be purchased from a local grocery market 1 day before the experiment. Aseptic conditions will be maintained over the whole process (use of a disinfected stainless steel knife, use of sterile gloves, and covering of the work benches with sterile sheets and use of biosafety cabinet). Samples will be stored under refrigeration at the edge of acceptable (4 - 5 ? C) for 12 days to be analyzed at day 0, 2, 4, 6, 8, 10, and 12 for sensory and microbiological tests.

Progress 10/01/14 to 09/30/17

Outputs
Target Audience:This project targeted different groups and individuals at different levels of the study. At initial steps, graduate and undergraduate students gained firsthand experiences through laboratory experiences. Minority students, including three graduate students and four undergraduate students, benefitted from this project by completing their theses, dissertations and research projects. The successful impact of this project will benefit the food industry, particularly the food packaging industry as well as the fresh produce industry. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Training activities: Students were trained on how to fabricate the film and provide the best possible nanocomposite film. They conducted different trials and determined the optimum concentration of each material to develop the film. They were also trained to use the high-tech instruments including X-ray diffraction, (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) to examine the microstructure and chemical changes of the developed film. Professional development: Students also participated in several conferences including IFT Annual Meetings, 2016; NCAFCS Annual Conference, 2016; Annual Biomedical Research Conference for Minority Students (ABRCMS), 2016; and North Carolina American Society for Microbiology, 2015 for professional development purposes and to increase their knowledge in this field. 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? The first objective of this study was to develop a biodegradable nanocomposite film made of sweet potato starch, montmorillonite (MMT) nanoclay and thyme essential oil. To formulate this film for packaging, we set out to find the optimum concentrations of each of these materials. Therefore, in the first step sweet potato starch was extracted from sweet potatoes and mixed with water and glycerol to develop a biodegradable film. Although the developed film exhibited good film formability, the physico-mechanical characteristics of the film needed to be improved. Thus, adequate amounts of MMT were added to the sweet potato starch solution. According to the literatures, up to 5% of MMT has improved these properties. We have tested different concentrations and found out that an addition of 3% of MMT will result in stronger film for packaging. At the end, thyme essential oil as an antibacterial agent was incorporated in the film. In vitro studies have shown that thyme essential oil has strong antibacterial effect. Adding the oil did not deteriorate the texture and film formability. For the second objective of this study, the mechanical properties of the developed film (film thickness, elongation at break, tensile strength, young modulus), optical characterization (surface color measurement) microstructural analysis (X-ray diffraction, (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM)), as well as barrier properties (water solubility, and water vapor permeability), were investigated. Incorporating the MMT nano clay generally, improved the mechanical properties of the films. Adding the thyme oil also enhanced the optical and barrier properties of the bio-nanocomposite films. The third objective was concerning the antibacterial activities of the developed film both in vitro and on baby spinach leaves. Incorporating thyme oil significantly (P<0.05) increased the antibacterial activities of the films against E.coli and S. Typhi. The population of E. coli and S. Typhi were effectively reduced on fresh baby spinach leaves below detectable level within 5 days whereas the control samples without essential oil maintained approximately 4.5 Log CFU/g. Objective four of the study is to conduct a sensory evaluation of baby spinach leaves wrapped in the film during the storage time. This test has not yet been completed. The major impact of this project is that the developed biodegradable film could be used for the packaging of different types of fresh produce to replace some of the existing plastics.

Publications

  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Issa, A., Ibrahim, S.A., & Tahergorabi, R. (2017). Impact of sweet potato starch-based nanocomposite films activated with thyme essential oil on the shelf-life of baby spinach leaves. Foods, 6, 43; DOI: 10.3390/foods6060043.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2017 Citation: Tahergorabi R. Antibacterial and physical properties of sweet potato starch nanocomposites for food packaging. ARD Research Symposium 2017, Atlanta, GA.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2017 Citation: Issa A, Sharaf Eddin A, Ibrahim S A, Dadsepah S A, & Tahergorabi R. Microstructure of nanocomposites films with sweet potato starch. NCAFCS Annual Conference, 2017, Charlotte, NC.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2017 Citation: Issa A, Sharaf Eddin A, Ibrahim S A, Dadsepah S A, & Tahergorabi R. Effect of nanoparticles and essential oil on physical characteristics of biodegradable films. NCAFCS Annual Conference, 2017, Charlotte, NC.
  • Type: Theses/Dissertations Status: Other Year Published: 2017 Citation: Aseel Issa. Biodegradable Nanocomposite Films Based on Sweet Potato Starch: Development, Characterization, and Their Antimicrobial Effects on the Shelf-Life of Packed Baby Spinach Leaves. Summer 2017.


Progress 10/01/15 to 09/30/16

Outputs
Target Audience:The successful impact of this project will benefit the food industry particularly food packaging industry as well as fresh produce industry. This project targets different groups and individuals at different levels of study. At initial steps, graduate and undergraduate students gained first-hand experiences through laboratory experiences. Minority students including three graduate students and four undergraduate students have benefitted from this project by conducting their theses, dissertations and research projects. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Training activities: Students were trained how to fabricate the film and provide the best possible nanocomposite film. They have tried different trials and found out the optimum concentration of each material to develop the film. They have been also trained on using the high tech instruments including X-ray diffraction, (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) to examine the microstructure and chemical changes of the developed film. Professional development: Students also participated in several conferences including IFT Annual Meetings, 2016, NCAFCS Annual Conference, 2016, Annual Biomedical Research Conference for Minority Students (ABRCMS), 2016, and North Carolina American Society for Microbiology, 2015 for professional development purposes and increase their knowledge in this filed. How have the results been disseminated to communities of interest?Results from this research were presented at the "Small Farms Field Day" on June 30, 2016 at the NC A&T SU farm through the cooperative extension program. This is an outreach event for the public and farmers to educate them about our research. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? The major impact of this project is the development of a biodegradable film that could be used for the packaging of different types of fresh produce to replace some of the existing plastics, thus reducing wastewhile increasing produce value for the consumer and removing added plastics from the environment. The first objective of this study was to develop a biodegradable nanocomposite film made of sweet potato starch, montmorillonite (MMT) nanoclay and thyme essential oil. In order to formulate this film for packaging we required to find the optimum concentrations of each of these materials. Therefore, in the first step sweet potato starch was extracted from sweet potatoes and mixed with water and glycerol to develop a biodegradable film. Although the developed film exhibited good film formability but the physico-mechanical characteristics of the film needed to be improved. Thus, adequate amount of MMT was added to the sweet potato starch solution. According to the literatures, up to 5% of MMT has improved these properties. We have tested different concentrations and found out that addition of 3% of MMT will result in stronger film for packaging. At the end, thyme essential oil as an antibacterial agent was incorporated in the film. In vitro studies have shown that thyme essential oil has strong antibacterial effect. Addition of the oil did not deteriorate the texture and film formability. For the second objective of this study, the mechanical properties of the developed film (film thickness, elongation at break, tensile strength, young modulus), optical characterization (surface color measurement) microstructural analysis (X-ray diffraction, (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM)), as well as barrier properties (water solubility, and water vapor permeability) were investigated. Incorporation of the MMT nano clay generally, improved the mechanical properties of the films. Addition of the thyme oil also enhanced the optical and barrier properties of the bio-nanocomposite films. The third objective was concerning about the antibacterial activities of the developed film both in vitro and on baby spinach leaves. Incorporation of thyme oil significantly (P<0.05) increased the antibacterial activities of the films against E.coli and S. Typhi. The population of E. coli and S. Typhi were effectively reduced on fresh baby spinach leaves below detectable level within 5 days whereas the control samples without essential oil maintained approximately 4.5 Log CFU/g. Sensory evaluation of baby spinach leaves wrapped in the film during the storage time is objective four of this study. This test has not been completed yet.

Publications

  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Issa A, Ibrahim SA, Tahergorabi R. (2016). Sweet Potato Starch/ Clay Nanocomposite Film: New Material for Emerging Biodegradable Food packaging. MOJ Food processing & Technology 3(3): 00073. DOI: 10.15406/mojfpt.2016.03.00073
  • Type: Other Status: Published Year Published: 2016 Citation: Issa A, & Tahergorabi R. Preparation and characterization of a bionanocomposite film based on sweet potato starch and thyme essential oil. IFT Annual Meetings Abstract Book, 2016, Chicago, IL.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: Issa A., & Tahergorabi R. Development of a novel antimicrobial nanocomposite film for food packaging. Proceedings of NCAFCS Annual Conference, 2016, New Bern, NC.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: Tahergorabi R, Issa A., Wilson C, & Ibrahim S .Evaluation of the antibacterial activities of nanocomposite films against foodborne pathogens on spinach leaves. Annual Biomedical Research Conference for Minority Students (ABRCMS), 2016, Tampa, Florida.
  • Type: Journal Articles Status: Other Year Published: 2016 Citation: Tahergorabi R, Issa A., Jones J, & Ibrahim S. Antibacterial and physico-mechanical properties of sweet potato starch nanocomposite films enriched with thyme essential oil. Proceeding of North Carolina American Society for Microbiology, 2015, NC State University, NC.


Progress 10/01/14 to 09/30/15

Outputs
Target Audience:The eventual target audience would include the food industry particularly fresh produce industry as well as food packaging industry. This project also targets different groups and individuals at different levels of study. At initial steps, graduate and undergraduate students gained first-hand experiences through laboratory experiences. Two graduate students and two undergraduate students have benefitted from this project by conducting their theses, dissertations and research projects. Once the project completed the obtained results will be published and disseminated through peer-reviewed journals. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Students were trained how to fabricate the film and provide the best possible nanocomposite film. They have tried different trials and found out the optimum concentration of each material to develop the film. We are in the process of finalizing this formula to move forward to the next objective. 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?This project is composed of four different objectives and researchers are planning to accomplish the next two objectives for the next reporting period: Objective 2: Evaluate the physico-mechanical characteristics of the films: different physico-mechanical properties of the film will be evaluated including film thickness, water vapor permeability, oxygen permeability, tensile strength, and color values. Objective 3: Investigate the antibacterial activity of the films on inoculated baby spinach leaves. Soon after conducting the tests related to physico-mechanical tests we will proceed to test the antibacterial effects of the films containing thyme essential oil on baby spinach leaves during storage time.

Impacts
What was accomplished under these goals? This project was initiated in October 2014. The first objective of this study was to develop a biodegradable nanocomposite film made of sweet potato starch, Montmorillonite (MMT) nanoclay and thyme essential oil. In order to formulate this film for packaging researchers were required to find the optimum concentrations of each of these materials. Therefore, in the first step sweet potato starch was extracted from sweet potatoes and mixed with water and glycerol to develop a biodegradable film. Although the developed film exhibited good film formability but the physico-mechanical characteristics of the film needed to be improved. Thus, adequate amounts of MMT was added to the sweet potato starch solution. According to the literatures, up to 5 percent of MMT has improved these properties. We have tested different concentrations and found that addition of 3 percent of MMT will result in stronger film for packaging. At the end, thyme essential oil as an antibacterial agent was incorporated in the film. In vitro studies have shown that thyme essential oil has strong antibacterial effect. Addition of the oil did not deteriorate the texture and film formability. The major impact of this project is that the developed biodegradable film could be used for the packaging of different types of fresh fruits and vegetables to replace some of the existing plastics.

Publications