MINISTRY OF EDUCATION AND TRAINING HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY AND EDUCATION GRADUATION THESIS MAJOR: FOOD TECHNOLOGY PH-SENSITIVE FILMS BASED ON STARCH, PVA, KARAYA GUM AND RED CABBAGE EXTRACT FOR FOOD MONITORING AND ELECTROCHEMICAL PRINTING INSTRUCTOR: NGUYEN VINH TIEN STUDENT: VU HOANG SAN NGUYEN LE KHANH LINH Ho Chi Minh city, June 2024 HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY AND EDUCATION FACULTY OF INTERNATIONAL EDUCATION GRADUATION PROJECT ID: 2024-20116158 PH-SENSITIVE FILMS BASED ON STARCH, PVA, KARAYA GUM AND RED CABBAGE EXTRACT FOR FOOD MONITORING AND ELECTROCHEMICAL PRINTING VU HOANG SAN Student ID: 20116158 NGUYEN LE KHANH LINH Student ID: 20116140 Major: FOOD TECHNOLOGY Supervisor: NGUYEN VINH TIEN, A. Ho Chi Minh City, June 2024 HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY AND EDUCATION FACULTY OF INTERNATIONAL EDUCATION GRADUATION PROJECT ID: 2024-20116158 PH-SENSITIVE FILMS BASED ON STARCH, PVA, KARAYA GUM AND RED CABBAGE EXTRACT FOR FOOD MONITORING AND ELECTROCHEMICAL PRINTING VU HOANG SAN Student ID:20116158 NGUYEN LE KHANH LINH Student ID:20116140 Major: FOOD TECHNOLOGY Supervisor: NGUYEN VINH TIEN, A. Ho Chi Minh City, June 2024 Ho Chi Minh City, Jun 20, 2024 xii ACKNOWLEDGEMENT To complete this graduation thesis, besides our own efforts, we have received invaluable support from our teachers, family, the university, and fellow students who have helped us overcome difficulties and challenges. Therefore, we would like to extend our sincere gratitude to everyone who has assisted us during this time.
We would like to express our heartfelt appreciation to the faculty members of the Department of Food Technology, Faculty of Chemical Engineering and Food Technology, Ho Chi Minh City University of Technology and Education, for imparting knowledge and providing all necessary equipment and facilities for us to complete our thesis. Our sincere thanks go to Associate Professor Dr. Nguyen Vinh Tien for his dedicated guidance, teaching, and sharing of knowledge and experience, which have greatly contributed to the completion of this graduation thesis. We also express our gratitude to the teachers in the Department of Food Technology for facilitating the use of equipment and measurement devices at the Food Technology Laboratory under the Faculty of Chemical Engineering and Food Technology, as well as for promptly addressing any queries we had.
We sincerely thank you! 1 DECLARATION "We solemnly declare that all the content presented in the graduation thesis is our own work. We assure that all referenced content in the graduation thesis has been accurately and fully cited according to the regulations." Ho Chi Minh City, June 5th, 2024 Signature 2 TABLE OF CONTENTS CHAPTER 1: INTRODUCTION .1 pH-sensitive Films .2 Electrochemical Printing Technology .3 Significance in Science and Practice .12 CHAPTER 2: LITERATURE REVIEW .1 Active and Intelligent Packaging .1 Definition and Importance .2 Current Trends and Innovations .3 Environmental Impact and Sustainability .3 Hydrolyzed Sterculia foetida .3 Active Substance - Anthocyanin .1 Introduction of Anthocyanin .4 Introduction to Electrochemical Printing .1 Definition and Historical Background .2 Basic Principles and Mechanisms .4 Factors Affecting the Electrochemical Printing Process with Anthocyanin and Polymer-Based Films. 30 CHAPTER 3: MATERIALS AND RESEARCH METHODS .1 Materials and chemical reagents. Hydrolysation of Resin from Sterculia foetida.
Extraction of anthocyanins from purple cabbage .5 Characterization of red cabbage extract. Determine the absorption spectrum and ability to change color according to pH of purple cabbage extract. Total Monomeric Anthocyanin Pigment Content. Determination of film properties.
Moisture content and water solubility .5 Water vapor transmission property .7 Fourier Transform Infrared Spectroscopy .7 Evaluation of the film antioxidant potential .8 Investigation of the pH-dependent color change ability of the films. 49 CHAPTER 4: RESULTS AND DISCUSSION .1 Characterization of red cabbage anthocyanins. Physical attributes of film samples .3 Moisture content and water solubility. Water vapor permeability.
Ultraviolet-visible light transmission. Electrochemical printing on film .81 CHAPTER 5: CONCLUSION AND RECOMMENDATIONS. 85 5 LIST OF TABLES Table 1. The six most common anthocyanidins in vascular plants.
Nutrient profile of raw cabbage and raw red cabbage. Error! Bookmar Table 3. The origin of the materials used in the study. Film formulation for one casting.
Preparing pH 4,5 and pH 1. Maximum absorbance value in 2 buffer solutions at 2 wavelengths. Color parameters and and total color difference values. Color values (L, a, b) and total color difference ∆E with SD of F5E samples.
Color values (L, a, b) and total color difference ∆E with SD of F10E samples. Color values (L, a, b) and total color difference ∆E with SD of F15E samples. Color values (L, a, b) and total color difference ∆E with SD of F20E samples. The Lab* coefficients and ∆E of the film surveyed change with varying anthocyanin content and printing time.
83 6 LIST OF FIGURES Figure 1. The structure of Polyvinyl Alcohol (PVA). Tai Ky Tapioca powder. The composition of starch.
Primary composition of anthocyanins. Some saccharides participating in anthocyanin modification. Typical acid components of the acylation in anthocyanins. Anthocyanins exhibit different chemical structures based on pH, alongside degradation reactions (with R1 as either H or a saccharide, and R2 and R3 as H or methyl).
The stabilization of the Cyanidin (Cy) semiquinone radical is achieved through resonance. The Brassica family. Process diagram for collecting karaya gum. Flow chart of the extraction process from purple cabbage.
Overview of the experiment process when changing 3 factors: extract, base film ratio, glycerol. Films after drying and preservation. The alteration of color in anthocyanin-rich extract from red cabbage across varying pH levels. A digital micrometer apparatus.
Experimental electrochemical printing system of 3V - power supply. The color change of purple cabbage extract in different pH buffer solutions (pH 2-12). The structural changes of anthocyanins (Abedi-Firoozjah et al. The absorption spectrum of anthocyanin extract from purple cabbage in pH buffer solutions (pH 2.
Structures showing both the flavylium cation (A) and its hemiketal form (B), adorned with either RZH or glycosidic substituents. Film samples’ thickness. Moisture contents and water solubility of films changing karaya gum. Moisture contents and water solubility of films changing red cabbage extract.
Moisture contents and water solubility of films changing glycerol content. UV–vis spectra of films changing (A) extract content, (B) hydrolysed karaya gum ratio, (C) glycerol content. Tensile strength lines of investigated films. Elongation at break of film samples.
FTIR spectra of films with karaya gum change. FTIR spectra of films with red cabbage extract change. FTIR spectra of films with glycerol change. ABTS radical scavenging activity of films in two differents environment.
Color transformation of polymer films following one-minute immersion in pH 2 to 12 buffer solutions. The images of various film types in a series of surveys, (A) Changing the concentration of purple cabbage extract and printing time, (B) F10E films under different sources, from left to right, with normal polarity and reverse polarity systems.1 pH-sensitive Films pH-sensitive films are designed to monitor pH changes by exhibiting distinct color changes, which can indicate spoilage or contamination, making them valuable in food packaging applications. The inclusion of natural pigments like anthocyanins enhances the environmental friendliness of these films (Silva-Pereira et al. The effectiveness of these films lies in the careful selection and combination of various components, each contributing to the film's overall properties and performance.
Starch, a widely used natural polymer, is favored for its film-forming properties, availability, and cost-effectiveness. Specifically, tapioca starch is noted for its clarity, flexibility, and oxygen barrier properties (Jimenez, Fabra et al. However, pure starch films can be brittle and lack sufficient mechanical strength, necessitating the incorporation of other materials to enhance their properties (Jridi et al. Polyvinyl alcohol (PVA), a synthetic polymer, is known for its biodegradability, non-toxicity, and good mechanical properties.
It significantly improves the mechanical strength and water resistance of starch-based films (Oun, Shin et al. Blending PVA with starch enhances film flexibility and reduces brittleness, making it suitable for various applications, including food packaging (Mittal, Garg et al. Karaya gum, a natural exudate from the Sterculia tree, is used as a thickening agent and stabilizer in film formulations. Its incorporation improves film flexibility and provides a uniform coating.
Additionally, karaya gum enhances the biodegradability of the film and its mechanical properties (Choudhary, Bains et al.The natural pigments used in these films are anthocyanins from red cabbage, which are responsible for the red, purple, and blue colors in many fruits and vegetables. Red cabbage extract, rich in anthocyanins, is particularly effective as a pH indicator due to its distinct color changes over a wide pH range (Castañeda-Ovando, de Lourdes Pacheco-Hernández et al. These pigments also have antioxidant properties, contributing to the overall functionality of the film. The strategic combination of these components results in a film that leverages the strengths of each material.
Starch provides the base matrix, PVA enhances mechanical properties and flexibility, karaya gum ensures uniformity and further flexibility, and anthocyanins offer pH sensitivity and antioxidant benefits. This synergy creates a multifunctional pH-sensitive film suitable for food monitoring and electrochemical printing, addressing both performance and sustainability concerns.2 Electrochemical Printing Technology Electrochemical printing is a novel technique that utilizes chemical reactions to change the color of pH-sensitive substances, which are then used to print information on polymer films without the need for synthetic inks as used in traditional printing methods. This approach offers several significant benefits that highlight its novelty and necessity. First, electrochemical printing ensures high precision in creating or modifying materials on a substrate, enabling the printing of complex designs with minimal waste.
This precision allows for the accurate deposition of active substances that can respond to environmental changes, such as pH fluctuations, making it ideal for detailed monitoring applications in food packaging (Zhai, Li et al. Moreover, this technique eliminates the need for synthetic inks, which can introduce contaminants and compromise food safety. By using natural pigments like anthocyanins in the electrochemical process, the risk of ink migration into food products is minimized, thus enhancing overall food safety (Cheng, Xu et al. Historically, previous studies have applied this technology to polymer films containing charged components with either positive or negative ions in their structure.
These films typically resulted in two main printed colors, red/pink and green/yellow, as observed in the works of (Zhai, Li et al. 2018) and (Yang, Zhai et al. However, the application of neutral polymers, such as those in the current study, has not been extensively explored. Neutral polymers may provide a more versatile range of color changes and reduce potential interactions with charged contaminants, broadening the utility of pH-sensitive films in various contexts.
Lastly, the goal of extending the potential applications of these printed polymer films is to enhance the preservation of perishable goods. By using this technology, the films can provide real-time information about the condition of food products with short shelf lives, enabling consumers to easily identify spoilage and ensure food safety. This capability not only improves consumer confidence but also reduces food waste by providing more accurate indicators of freshness (Luchese, Garrido et al. In conclusion, the integration of electrochemical printing with pH-sensitive films represents a significant advancement in food monitoring technologies.
This approach leverages the unique properties of starch, PVA, karaya gum, and anthocyanins, combined with the innovative capabilities of electrochemical printing, to develop advanced, multifunctional films suitable for a wide range of applications. This research aims to address existing gaps, enhance food safety, and promote sustainability in packaging technologies.2 Research Objectives The primary objective of this experiment is to investigate the effects of various components in the formulation of pH-sensitive polymer films. The study aims to develop and optimize polymer films by examining the influence of hydrolyzed karaya gum, the concentration of red cabbage extract containing anthocyanins, and the amount of glycerol used as a plasticizer.