Research progress on humidity triggered biobased deoxygenation packaging using porous modified calcium carbonate as a carrier

Research Overview: Porous Mineral Carrier Carries Natural Deoxidizer

A study published in Packaging Technology and Science investigated the use of porous modified calcium carbonate (MCC) as a solid carrier to load two natural deoxygenating compounds, gallic acid (GA) and ascorbic acid (AA), for a humidity triggered deoxygenation system in food packaging. MCC is a porous mineral material with a large specific surface area. Its structure was characterized by mercury intrusion porosimetry, nitrogen adsorption (BET), and scanning electron microscopy, and its deoxygenation activity was evaluated in the temperature range of 37% -100% relative humidity and 5 ° C -30 ° C.

Key Data and Performance

• In terms of load capacity, MCC was loaded with 9-20 wt% GA and 9-25 wt% AA, respectively. After loading, MCC maintained a porous structure, but the pore volume and specific surface area decreased with increasing load capacity.

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• Medium load (13 wt% GA or AA) showed the highest utilization efficiency of deoxidizer.

. Under the condition of ≥ 87% RH, MCC loaded with 13 wt% GA reduced the oxygen concentration of 2 vol -% in the modified atmosphere packaging to below 0.01 vol -% within 27 days at 21 ° C; At 30 ° C, the deoxygenation rate reached 14.1 mL of O ₂ d ⁻¹ gGA ⁻¹.

• The activity of MCC loaded with AA was low, and the maximum deoxygenation rate under comparable conditions was 4.5 mL of O ₂ d ⁻¹ gAA ⁻¹.
• No measurable deoxygenation behavior was observed below 67% RH; The temperature mainly affects the reaction kinetics, and the GA loading system is still effective under refrigeration conditions, but the rate decreases.
• In long-term atmospheric pressure testing, the oxygen absorption capacity of GA and AA loading systems exceeded 300 mL O ₂ gGA ⁻¹ and 100 mL O ₂ gAA ⁻¹, respectively.

Significance for the polymer additives and packaging materials industry

The significance of this study is to provide a “carrier design” approach: the oxygen removal function is not only determined by the active substance itself, but also by the accessibility, loading level, and humidity response of the porous carrier, which jointly determine the system performance.

. For high moisture activity food packaging, this humidity triggering mechanism means that the deoxygenation function can be activated after the moisture conditions inside the packaging reach a threshold, rather than consuming active ingredients in advance during the drying and storage stages. From the perspective of packaging material formulation and processing, MCC, as a mineral carrier, has potential space for composite with polyolefin and other packaging resins. However, the research itself focuses on carrier loading and oxygen removal performance evaluation, and does not involve extrusion, blending or film forming processes with polymer matrices. If such systems are to be introduced into packaging films or containers, the interaction between processing stability and antioxidant systems is worth paying attention to: packaging resins usually require antioxidants to suppress thermal oxidative degradation during hot processing such as extrusion and blown film, and the design goal of deoxygenation active components is precisely to consume oxygen. The synergy and boundary between the two in the formulation need to be verified in specific systems. In addition, food contact compliance is a prerequisite for the implementation of such active packaging, and the load, carrier, and final packaging materials must meet corresponding migration and safety assessment requirements. Under the trend of sustainable packaging, GA and AA are active compounds derived from biological sources, while MCC is a mineral material. This system provides a research direction that can replace some traditional deoxygenation solutions to reduce residual oxygen in packaging and extend food shelf life. For the application of recycled materials, post consumer resin recycling often involves oxidation degradation history and odor issues. Antioxidants and processing stabilization systems play a role in stabilizing the melt and inhibiting degradation in recycled material formulations; There is currently no research data to support the combination of deoxygenation packaging and recycled material systems, and caution should be taken. Overall, this work demonstrates a reasonable pathway for regulating humidity responsive deoxygenation behavior using porous mineral carriers, providing reference performance parameters and mechanism understanding for the active design of high humidity food packaging.

Information source:Porous Modified Calcium Carbonate as an Efficient Carrier for Gallic and Ascorbic Acids in Humidity‐Activated Oxygen Scavenging Systems， Organized by Herun Chemical.