Development of antioxidant and antimicrobial edible coatings incorporating bacterial cellulose, pectin, and blackberry pomace

Pectin-Cellulose Nanofiber Composites: Biodegradable Materials for Modified Atmosphere Packaging

Pectin blended with cellulose nanofiber (CNF) sourced from wood pulp has excellent potential for modified atmosphere packaging (MAP), as demonstrated with refrigerated or sliced fruits enclosed in parchment coated with pectin-CNF composites. Addition of sodium borate (NaB) augments the antioxidant capacity of the composite, most likely through the generation of unsaturated pectic acid units. Packaging materials coated with pectin-CNF-NaB composites demonstrate better humidity regulation in refrigerated spaces over a 3-week period relative to uncoated controls (50% less variation), with improved preservation of strawberries as well as a reduction in the oxidative browning of sliced apples. Pectin-CNF films are both biorenewable and biodegradable as confirmed by their extensive decomposition in soil over several weeks, establishing their potential as a sustainable MAP material. Lastly, self-standing films are mechanically robust at 80% RH with tensile strength and toughness as high as 150 MPa and 8.5 MJ/m2 respectively. These values are on par with other bioplastic composites and support the practical utility of pectin-CNF composites in functional packaging applications.

A comprehensive review on the functionality and biological relevance of pectin and the use in the food industry

Pectin is a natural biopolymer, which can be extracted from food by-products, adding value to raw material, with a structure more complex than that of other polysaccharides. The gelling properties of these molecules, together with the bioactivity that these can exert, make them suitable to be used as ingredients and bioactive agents. In this review, the characterization of pectin (structure, sources, techno-functional, and biological properties), the extraction methods, and their use in the food industry (food packaging, as carriers, and as ingredients) are described. Different by-products can be used as substrates to extract pectin, enhancing a sustainable food system as described by the circular economy principles. Pectin is characterized for their techno-functional and biological properties, such as gelling and thickening properties or modulation of microbiota both in animals and humans. Such properties make these molecules suitable for a wide range of applications within the food chain, serving as packaging or carriers in foodstuff, or for direct use as functional ingredients as fiber. Overall, pectin has been shown to exert as promising components to be introduced in the food system, although further research on scaling-up the production process and feasibility has to be done.

Cost-Effective Synthesis of Bacterial Cellulose and Its Applications in the Food and Environmental Sectors

Bacterial cellulose (BC), also termed bio-cellulose, has been recognized as a biomaterial of vital importance, thanks to its impressive structural features, diverse synthesis routes, high thermomechanical properties, and its ability to combine with multiple additives to form composites for a wide range of applications in diversified areas. Its purity, nontoxicity, and better physico-mechanical features than plant cellulose (PC) make it a better choice for biological applications. However, a major issue with the use of BC instead of PC for various applications is its high production costs, mainly caused by the use of expensive components in the chemically defined media, such as Hestrin-Schramm (HS) medium. Furthermore, the low yield of BC-producing bacteria indirectly accounts for the high cost of BC-based products. Over the last couple of decades, extensive efforts have been devoted to the exploration of low-cost carbon sources for BC production, besides identifying efficient bacterial strains as well as developing engineered strains, developing advanced reactors, and optimizing the culturing conditions for the high yield and productivity of BC, with the aim to minimize its production cost. Considering the applications, BC has attracted attention in highly diversified areas, such as medical, pharmaceutics, textile, cosmetics, food, environmental, and industrial sectors. This review is focused on overviewing the cost-effective synthesis routes for BC production, along with its noteworthy applications in the food and environmental sectors. We have made a comprehensive review of recent papers regarding the cost-effective production and applications of BC in the food and environmental sectors. This review provides the basic knowledge and understanding for cost-effective and scaleup of BC production by discussing the techno-economic analysis of BC production, BC market, and commercialization of BC products. It explores BC applications as food additives as its functionalization to minimize different environmental hazards, such as air contaminants and water pollutants.

Optical and thermal properties of edible coatings for application in solar drying

Solar drying is a sustainable process that may impact the quality of dried food. This is because, pigments contained in food are sensitive to sunlight, and exposure to ultraviolet radiation can affect them. We applied biopolymer-based coatings on strawberry, from hydro-colloidal solutions of Opuntia ficus indica-mucilage, fenugreek, xanthan gum, gum Arabic, and guar gum to evaluate their potential use as UV filters for solar drying of food. Thermal properties and the optical transmittance, absorbance and reflectance of the coatings were measured to assess their influence on food-sunlight interaction. During the drying experiments, the moisture content, total anthocyanins (TA), and total phenolic compounds (TPC) were measured. Optical and thermal properties are influenced by the biopolymer-based coatings. Also, the optical properties are influenced by the coating thickness. The differences in optical and thermal properties influence the drying process. Differences exist in the drying rate for strawberry slices with coating, compared with those without the coatings. In general, the TA and TPC content in the product are better preserved under solar drying than in control experiments done in a drying oven. A partial transmittance of solar UV radiation is recommended to obtain increased TA and TPC contents in the dried product.