Potential of cereal-based husks to achieve several SDGs, including biodegradable packaging

The United Nations has targeted the reduction of food losses in both production and supply chains by 2030 in its SDGs (Target 12.3). A significant amount of food waste is discarded from food industries along their production, processing, and supply chain (Caldeira et al., 2019) which contributes significantly to environmental pollution, economic inequality, and climate change (FAO, 2019). Massive research efforts have been directed in recent years to find out the sustainable approaches to utilize food waste products to recover energy in the form of biofuels, bioconversion of food waste into marketable products, and reduce environmental pollution using food waste ingredients (Bilal et al., 2018). Pollutants in the waterThe presence of heavy metals in water is a critical issue as it can cause severe toxicity in living organisms leading to serious illnesses. Due to the presence of toxic heavy metals in the water streams, water resources are under stress all over the world. The food chain is also badly affected due to the occurrence of heavy metals in water (Khalil et al., 2020). Dyes and colors eliminated from textile industries in the form of textile wastewater get mixed with our aquatic freshwater and affects aquatic life. These dyes also pass through the entire food chain as seafood is a good source of nutrition (Kheddo et al., 2020). Antibiotics are a threat to our ecosystem because of their relatively stable structure, complex biological activity, and resistance to biodegradation. Contamination of water with antibiotics transforms antibiotic resistance genes and produces composite pollutants by the combination of antibiotics with other pollutants present in wastewater that are very hazardous to the health of living organisms (Yang et al., 2020). Similarly, organophosphorus pesticides penetrates deep into the soil and pollute the groundwater due to their high water solubility (Raju et al., 2019). Exposure to these pesticides for a long time in high doses can cause chromosomal aberrations, carcinogenic effects, and hypoimmunity (Sinha & Banda, 2018). Food waste, a source of renewable energyFood waste is also a source of renewable energy with a significant potential to produce biofuels for heat, transportation, and electricity. Biofuels produced from food waste materials like biogas, biodiesel, and bioethanol lead to a reduction in harmful nitrogen and sulfur oxides and are thus beneficial to the climate. The production of environmentally friendly and cleaner fuels as an alternative to the available fossil fuels is a much-needed solution to meet the high energy demand sustainably (Popp et al., 2021). Biodegradable materials for packagingPlastic materials have vast use for packaging because of their resistance to mechanical and environmental factors, flexibility, excellent printability, and low cost. But these plastic materials have detrimental effects on the environment as they degrade over the decades and release harmful chemicals which can deteriorate the quality of food. Hence, it is safer to use biodegradable materials for packaging purposes as compared to plastics while considering environmental and health concerns (Horodytska et al., 2018). Research about other usesPrevious investigations have revealed numerous possibilities for utilization of food waste products such as the formulation of fertilizers, composts (Ahmad et al., 2022; Ahouangninou et al., 2022; Hayat et al., 2022), and animal feed (Fazili et al., 2021; Ismael et al., 2022; Zaki et al., 2021), development of functional foods and nutraceuticals (Lavelli, 2021), preparation of biodegradable packaging (Aouat et al., 2021; Hammajam et al., 2019; Mittal et al., 2020; Sirichalarmkul and Kaewpirom, 2021; Tan et al., 2022), production of biofuels (S. B. Tiwari et al., 2021; Embong et al., 2021; Shankar et al., 2019; AZ et al., 2021), and treatment of wastewater (Habiba et al., 2022; Dan et al., 2021; Sanka et al., 2020; Akhayere et al., 2020; Prajapati et al., 2022). Composition of cereal based husksCereal-based husks are mainly composed of cellulose, hemicellulose, and lignin. Wheat husk (WH) contains 36% of cellulose, 18% of hemicellulose, and 16% of lignin (Santos et al., 2019). Rice husk (RH) is composed of 35% cellulose, 25% hemicellulose, and 20% lignin (Tiwari et al., 2022). Corn husk (CH), barley husk (BH), and millet husk (MH) also have cellulose, hemicelluloses, and lignin as their main constituents (Chen et al., 2023; Fortunati et al., 2016; Gairola et al., 2022). Cereal-based husks are separated as waste in cereal processing industries when cereal grains are cleaned, dehulled, and milled into various cereal flours. These byproducts are produced as a waste of cereal processing industries in about 70?80 million tons worldwide every year (Chen et al., 2023). Cereals as adsorbents for pollutants?This review describes the utilization of cereal-based husks like WH, RH, CH, BH, and MH to make adsorbents for the removal of Hg, Pb, Cd, Cr, Co, Fe, Ni, Cu, and other heavy metals, dyes like reactive blue (RB), methylene blue (MB), basic red (BR), basic blue (BB), crystal violet (CV) and tartrazine, antibiotics like ciprofloxacin (CIP), beta-lactam amoxicillin, and beta-lactam cefixime, pesticides like 2,4-dichlorophenoxy acetic acid (2,4-D), and other petrol contaminants from the wastewater. Cereals to produce energy and packaging materialsThe production of biogas, biodiesel, bioethanol, and manufacturing of bioplastics, biodegradable films, packaging paper, and biodegradable foams from cereal-based husks are also described in detail with an aim of effective cereal waste management. Hierarchical approach to the management of waste materialsThe European Union (EU) Directive 2018/851/EC imposed a hierarchical approach to the management of waste materials discarded from various industries. According to which recovery, re-use, disposal, recycling, or prevention of waste from accumulation should be described from top to bottom in detail by adopting a waste hierarchy approach (European Parliament and Council of the European Union, 2018). In numerous papers published on the topic of waste management, the products that are fit for human consumption are separated by a dotted line from those products that are unfit for human consumption. In some studies, economically viable byproducts are separated from uneconomical ones. Some researchers also categorized the byproducts into various categories based on their best place of utilization i.e. food fortificant or biopreservative, animal feed, fertilizers, non-food products, and biofuels, etc. (Lavelli, 2021). In this paper, the source of cereal-based husks and their sustainable utilization is described by adopting a simple waste hierarchy approach as shown in Fig. 1. AbstractBackgroundFood waste management (FWM) has gained much attention over the past few years in industries, research institutions, and national and international organizations due to its significant potential to produce valuable products and control environmental pollution. Finding the sustainable approaches to utilize these waste materials is a current focus of many researchers. Scope and approachThis review aims to explore the potential of cereal-based husks from 5 major cereal grains (wheat, rice, corn, barley, and millet) to achieve goals?6 (clean water and sanitation), 7 (affordable and clean energy), 9 (industry, innovation, and infrastructure), and 12 (responsible consumption and production) of the 17 sustainable development goals (SDGs) set out by the united nations to make the world more healthy and developed with minimum environmental pollution. Key findings and conclusionCereal-based husks can be utilized to make adsorbents to remove heavy metals, dyes, antibiotics, pesticides, and petrol contaminants from wastewater. These husks can be utilized to produce clean and affordable energy alternatives such as biogas (methane), organic bio-oil, biodiesel, and bioethanol. Moreover, the biopolymeric matrices of these husks can be efficiently used to make bioplastics, biocomposite films, biodegradable foams, and packaging paper for food and other industries.The figure is Fig. 1 of the original paper, the graphical abstract SourceUtilization of cereal-based husks to achieve sustainable development goals: Treatment of wastewater, biofuels, and biodegradable packagingSyed Ali Hassan, Mueen Abbas, Waqar Mujahid, Waqar Ahmed, Saeed Ahmad, Abid Aslam Maan, Aamir Shehzad, Zuhaib F. Bhat & Rana Muhammad AadilTrends in Food Science & Technology,?Volume 140, October 2023, 104166https://doi.org/10.1016/j.tifs.2023.104166https://www.sciencedirect.com/science/article/abs/pii/S0924224423002819?dgcid=author