A new procedure to prepare transparent, colourless and low-water-soluble edible films using blood plasma from slaughterhouses

Hydrolyzed sewage sludge as raw bio-based material for hermetic bag production

This study aimed to assess the potential of sewage sludge, a significant residue of wastewater treatment plants (WWTPs), as a sustainable resource for producing a bio-based material for hermetic bags (BMHB), in order to reduce the dependency on petroleum-derived plastics. The approach involved the application of thermal hydrolysis to solubilize sewage sludge, and it systematically examined critical process parameters, including temperature (120-150 °C), residence time (1-4 h), and medium pH (6.6-10). Results revealed that alkaline thermal hydrolysis significantly enhanced biomolecule solubilization, particularly proteins (289 ± 1 mg/gVSSo), followed by humic-like substances (144 ± 6 mg/gVSSo) and carbohydrates (49 ± 2 mg/gVSSo). This condition also increased the presence of large-and medium-sized compounds, thereby enhancing BMHB mechanical resistance, with puncture resistance values reaching 63.7 ± 0.2 N/mm. Effective retention of UV light within the 280-400 nm range was also observed. All BMHB samples exhibited similar properties, including water vapor permeability (WVP) (∼3.9 g * mm/m2 * h * kPa), hydrophilicity (contact angles varied from 35.4° ± 0.3 to 64° ± 5), solubility (∼95%), and thermal stability (∼74% degradation at 700 °C). Notably, BMHB proved to be an eco-friendly packaging for acetamiprid, an agricultural pesticide, preventing direct human exposure to harmful substances. Testing indicated rapid pesticide release within 5 min of BMHB immersion in water, with only 5% of BMHB residues remaining after 20 min. Additionally, the application of this material in soil was considered safe, as it met regulatory limits for heavy metal content and exhibited an absence of microorganisms.

Turning Food Protein Waste into Sustainable Technologies

For each kilogram of food protein wasted, between 15 and 750 kg of CO2 end up in the atmosphere. With this alarming carbon footprint, food protein waste not only contributes to climate change but also significantly impacts other environmental boundaries, such as nitrogen and phosphorus cycles, global freshwater use, change in land composition, chemical pollution, and biodiversity loss. This contrasts sharply with both the high nutritional value of proteins, as well as their unique chemical and physical versatility, which enable their use in new materials and innovative technologies. In this review, we discuss how food protein waste can be efficiently valorized not only by reintroduction into the food chain supply but also as a template for the development of sustainable technologies by allowing it to exit the food-value chain, thus alleviating some of the most urgent global challenges. We showcase three technologies of immediate significance and environmental impact: biodegradable plastics, water purification, and renewable energy. We discuss, by carefully reviewing the current state of the art, how proteins extracted from food waste can be valorized into key players to facilitate these technologies. We furthermore support analysis of the extant literature by original life cycle assessment (LCA) examples run ad hoc on both plant and animal waste proteins in the context of the technologies considered, and against realistic benchmarks, to quantitatively demonstrate their efficacy and potential. We finally conclude the review with an outlook on how such a comprehensive management of food protein waste is anticipated to transform its carbon footprint from positive to negative and, more generally, have a favorable impact on several other important planetary boundaries.

Exploring the prospects of the fifth quarter in the 21st century

A variable proportion of slaughtered livestock, generally referred to as the fifth quarter, is not part of the edible dressed meat and regarded as animal byproduct. In order for the fifth quarter to play a significant role in the current effort toward a circular bio-based economy, it has to successfully support food security, social inclusivity, environmental sustainability, and a viable economy. The high volume of these low-value streams and their nutrient-dense nature can facilitate their position as a very important candidate to explore within the context of a circular bio-based economy to achieve some of the United Nations Sustainable Development Goals (UN-SDGs). While these sources have been traditionally used for various applications across different cultures and industries, it seems evident that their full potential has not yet been exploited, leaving these products more like an environmental burden rather than valuable resources. With innovation and well-targeted interdisciplinary collaborations, the potential of the fifth quarter can be fully realized. The present review intends to explore these low-value streams, their current utilization, and their potential to tackle the global challenges of increasing protein demands while preventing environmental degradation. Factors that limit widespread applications of the fifth quarter across industries and cultures will also be discussed.

Novel Bovine Plasma Protein Film Reinforced with Nanofibrillated Cellulose Fiber as Edible Food Packaging Material

Proteins, such as those in blood from slaughterhouses, are a good option for developing edible films. However, films made exclusively from proteins have low strength and high water solubility, which makes them difficult to use in the food industry. The use of cellulosic material, such as nanofibrillated cellulose (NFC), can improve the properties of these films. In the present work, bovine plasma was acidified and treated with ethanol to precipitate its proteins, and these proteins were used to prepare films reinforced with several concentrations of NFC. In addition, control films prepared with untreated bovine plasma and reinforced with NFC were prepared as well. These new edible films were characterized according to their mechanical properties, water vapor permeability, light transmittance, and microstructure. Furthermore, the film with the best properties was selected to be additivated with nisin to test its antimicrobial properties by wrapping meat previously contaminated with Staphylococcus aureus. In this sense, films prepared with the extracted proteins showed better properties than the films prepared with untreated plasma. In addition, the results showed that the reinforcement of the films with a 10% (w/w) of NFC decreased their water solubility and improved their puncture strength and water vapor barrier properties. Finally, the addition of nisin to the films prepared with extracted protein from bovine plasma and NFC gave them antimicrobial properties against S. aureus.

Biodegradable Packaging Materials from Animal Processing Co-Products and Wastes: An Overview

Biodegradable polymers are non-toxic, environmentally friendly biopolymers with considerable mechanical and barrier properties that can be degraded in industrial or home composting conditions. These biopolymers can be generated from sustainable natural sources or from the agricultural and animal processing co-products and wastes. Animals processing co-products are low value, underutilized, non-meat components that are generally generated from meat processing or slaughterhouse such as hide, blood, some offal etc. These are often converted into low-value products such as animal feed or in some cases disposed of as waste. Collagen, gelatin, keratin, myofibrillar proteins, and chitosan are the major value-added biopolymers obtained from the processing of animal's products. While these have many applications in food and pharmaceutical industries, a significant amount is underutilized and therefore hold potential for use in the generation of bioplastics. This review summarizes the research progress on the utilization of meat processing co-products to fabricate biodegradable polymers with the main focus on food industry applications. In addition, the factors affecting the application of biodegradable polymers in the packaging sector, their current industrial status, and regulations are also discussed.