When: Wednesday 22 June 2022, at 11am-12pm
Where: BioPRIA Building 59, 15 Alliance Lane, Clayton VIC 3800
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Novel paper-based materials for high temperature food packaging
Presenter: Dr. Mostafa Dehghani
Abstract: Food processing industry selects the packaging material according to food product requirement considering factors like heat resistibility and sealability, process ability, printability, strength, barrier properties (water, oil and gas barrier), cost-effectiveness, sustainability and legal requirements. Various materials like paper, plastic, glass, aluminum, wood or combination of any of these are used for food packaging depending on their pros and cons.
Pulp and paper industry is one of the major industrial sectors everywhere contributing not only to Gross Domestic Product but also surprisingly to environmental pollution and health hazards. Paper and paperboard based materials are one of the earliest and largest used packaging form for food products like milk and milk based products, beverages, dry powders, confectionary, bakery products etc. owing to its eco-friendly hallmark.
Paper and paperboards encompass 31% of the global packaging market segment and are most widely used in food packaging for containment and protection of the food products, convenience during storage or consumption and communication of the relevant information to consumers including its marketing aspects. However, the usage of paper-based materials for the packaging of ready to heat (RTH) and ready to cook (RTC) products containing high content of water and food preparation processes under vigorous heating (200-250 °C) has been challenging due to the lack of knowledge and complexity of it.
Plain paper might be insufficient for these categories of food packaging because of poor barrier properties, low heat resistant and sealability, also the color change. So, it should be either modified in structure or impregnated with some additive or laminated with other sustainable and
biodegradable materials to improve its functional properties. Among the usable additives, those with hydrophobicity and high thermal and mechanical properties such as Alkyl ketene dimers (AKDs), Clay nanomaterials, artificial cellulose fibers, lignocellulose, and chitin based bioplastics can be selected as the possible candidates for this application. Although several attempts have been made to produce a paper-based food grade material for high temperature food packaging containing either high water content or vigorous heating process, the success rate is low. Hence, the need for a novel biopolymeric composite or method of production with high thermal and mechanical properties that can be used for packaging of food under high temperature (200-250 °C) is highly demanding and necessary to preserve the environment. This study will focus on providing a fundamental knowledge regarding the quantification and production of paper-based materials with great thermal, mechanical, and hydrophobic properties that can be used in food packaging of materials under high temperature with minimum health concern.
Selecting cellulose nanocrystals for a desired application: The importance of size and surface chemistry
Presenter: Dr. Christine Browne
Abstract: There is increasing consumer awareness of the environmental impact products have on the natural environment and driving a desire for more sustainable and recyclable options. Due to these demands’ cellulose-based materials are garnering much attention due to them being renewable, recyclable and environmentally friendly. Cellulose nanocrystals (CNC), a subset of cellulose materials, are highly crystalline with typical lengths of 100-500 nm and diameters of 3-5 nm. CNCs have been shown to have applications in areas such as sensors, optical devices and viscosity modifiers. Due to these varied applications it is vital to characterise CNCs prior to use to select the most appropriate properties.
Within this study we have demonstrated that the size and surface chemistry of two difference sources of CNCs can be quickly determined with rheological and small angle x-ray scattering (SAXS) measurements. These measurements were benchmarked against the techniques of TEM, AFM, DLS, conductometric titration, zeta potential and polarised optical imaging. It was shown that CNC1, was smaller in length and dispersity values along with a higher sulfur content when compared with CNC2. Though the higher sulfur content did not correspond to an increase in zeta potential. The addition of electrolyte to the suspensions during the rheology measurements determined that CNC1 was able to form a liquid crystal, whereas CNC2 was unable. These measurements have shown that CNC1 would be suitable for use in optical materials and CNC2 would be more suited to applications where control of viscosity is important.