ascorbic-acid and iminodiacetic-acid

Many packaged goods undergo transition metal-catalyzed oxidative spoilage. Recently, a nonmigratory photocurable metal-chelating coating was developed as an innovative active packaging approach to control oxidation of foods. In the present study, we investigate the influence of competing ions and increasing viscosity on the iron-chelating capacity and antioxidant efficacy of this coating in a model complex food system. The addition of calcium and magnesium causes a decrease in iron chelating capacity; however, 61% chelating capacity of materials was retained when 0.8 M sodium was present. Materials retained iron-chelating capacity even in solutions of 2700 cP, similar to the viscosity of salad dressing. Additionally, metal-chelating films significantly delayed transition metal-catalyzed ascorbic acid degradation, even in the presence of competing ions and at increased viscosity. These results suggest that metal-chelating active packaging coatings may present a new technological approach to addressing consumer demands for reduced additive use while controlling food spoilage and waste.

Topics: Antioxidants; Ascorbic Acid; Calcium; Food; Food Packaging; Imino Acids; Iron Chelating Agents; Magnesium; Metals; Methylcellulose; Oxidation-Reduction; Polymers; Surface Properties; Viscosity

Synthetic metal chelators (for example, ethylenediaminetetraacetic acid, EDTA) are widely used as additives to control trace transition metal induced oxidation in consumer products. To enable removal of synthetic chelators in response to increasing consumer demand for clean label products, metal-chelating active food packaging technologies have been developed with demonstrated antioxidant efficacy in simulated food systems. However, prior work in fabrication of metal-chelating materials leveraged batch chemical reactions to tether metal-chelating ligands, a process with limited industrial translatability for large-scale fabrication. To improve the industrial translatability, we have designed a 2-step laminated photo-grafting process to introduce metal chelating functionality onto common polymeric packaging materials. Iminodiacetic acid (IDA) functionalized materials were fabricated by photo-grafting poly(acrylic acid) onto polypropylene (PP) films, followed by a second photo-grafting process to graft-polymerize an IDA functionalized vinyl monomer (GMA-IDA). The photo-grafting was conducted under atmospheric conditions and was completed in 2 min. The resulting IDA functionalized metal-chelating material was able to chelate iron and copper, and showed antioxidant efficacy against ascorbic acid degradation, supporting its potential to be used synergistically with natural antioxidants for preservation of food and beverage products. The 2-step photo-grafting process improves the throughput of active packaging coatings, enabling potential roll-to-roll fabrication of metal-chelating active packaging materials for antioxidant food packaging applications.. To address consumer and retail demands for "clean label" foods and beverages without a corresponding loss in product quality and shelf life, producers are seeking next generation technologies such as active packaging. In this work, we will report the synthesis of metal-chelating active packaging films, which enable removal of the synthetic additive, ethylenediamine tetraacetic acid. The new synthesis technique improves the throughput of metal-chelating active packaging coatings, enabling potential roll-to-roll fabrication of the materials for antioxidant food packaging applications.

Topics: Antioxidants; Ascorbic Acid; Chelating Agents; Copper; Food Packaging; Imino Acids; Iron; Oxidation-Reduction; Photochemical Processes; Polymerization; Polypropylenes

New organic acid mixtures have been investigated to recover the valuable metal ions from the cathode material of spent Li-ion batteries. The cathodic active material (LiCoO2) collected from spent Li-ion batteries (LIBs) is dissolved in mild organic acids, iminodiacetic acid (IDA) and maleic acid (MA), to recover the metals. Almost complete dissolution occurred in slightly excess (than the stoichiometric requirement) of IDA or MA at 80°C for 6h, based on the Co and Li released. The reducing agent, ascorbic acid (AA), converts the dissolved Co(III)- to Co(II)-L (L=IDA or MA) thereby selective recovery of Co as Co(II)-oxalate is possible. The formation of Co(III)- and Co(II)-L is evident from the UV-Vis spectra of the dissolved solution as a function of dissolution time. Thus, the reductive-complexing dissolution mechanism is proposed here. These mild organic acids are environmentally benign unlike the mineral acids.

Topics: Ascorbic Acid; Cobalt; Electric Power Supplies; Imino Acids; Industrial Waste; Lithium; Maleates; Recycling; Waste Management