A Review on the Challenges and Choices for Food Waste Valorization: Environmental and Economic Impacts

Abstract

Valorization of food waste (FW) is instrumental for reducing the environmental and economic burden of FW and transitioning to a circular economy. The FW valorization process has widely been studied to produce various end-use products and summarize them; however, their economic, environmental, and social aspects are limited. This study synthesizes some of the valorization methods used for FW management and produces value-added products for various applications, and also discusses the technological advances and their environmental, economic, and social aspects. Globally, 1.3 billion tonnes of edible food is lost or wasted each year, during which about 3.3 billion tonnes of greenhouse gas is emitted. The environmental (-347 to 2969 kg CO₂ equiv/tonne FW) and economic (-100 to $138/tonne FW) impacts of FW depend on the multiple parameters of food chains and waste management systems. Although enormous efforts are underway to reduce FW as well as valorize unavoidable FW to reduce environmental and economic loss, it seems the transdisciplinary approach/initiative would be essential to minimize FW as well as abate the environmental impacts of FW. A joint effort from stakeholders is the key to reducing FW and the efficient and effective valorization of FW to improve its sustainability. However, any initiative in reducing food waste should consider a broader sustainability check to avoid risks to investment and the environment.

Figure 1

Share of various global food waste. [Fruits and vegetables are the major contributors to the total FW in different jurisdictions followed by cereals, root and tubers, milk, meat, and others. However, the generation of FW depends on the types of food, processing stages, and food supply chains, as well as the jurisdictions.]

Figure 2

Household-level food waste generation in selected countries and in the world. [The generation of household-level FW depends on technological advancement, and socioeconomic, logistics, infrastructure, and management, as well as the purchasing capacity. FW is greater in developed countries as compared to the developing countries.]

Figure 3

Schematic of the food waste valorization processes, products, and applications (AD, anaerobic digestion; HTC, hydrothermal carbonization). [This figure shows the potential sources of food waste, valorization technologies, and value-added products generated from FW and their applications in different areas, which can play a determinant role in the sustainability of the FW valorization processes. The product yields also depend on the valorization techniques (stage 1 and/or stage 2), pretreatments, and types of FW.]

Figure 4

Food waste valorization approaches for a circular bioeconomy. [For a circular bioeconomy, edible and inedible FW need to be separated at sources and at different stages of the food supply chains. On the basis of the type of FW, the first priority of edible portions is to divert for human consumption, and the low-quality edible food can be sent to the animal/fishery/insect industry. However, some of the inedible parts can be remanufactured for various applications. Spoiled or expired food and the rest of the inedible portion of FW can be sent to a biorefinery for nutrients and energy recovery.]

Figure 5

Food waste minimization framework. [It seems that transdisciplinary approaches are required where all of the stakeholders in the food sectors need to be involved in reducing FW. Consequently, a multisectoral approach would be required to minimize FW generation in different jurisdictions. For example, intensive awareness of the implications of FW in the environment, economy, and society might be the key for emerging economies. In addition, supply/packaging/marketing and purchasing strategies may also play a crucial role in controlling FW, such as bulk buying or push selling often become one of the causes of FW as the expiration date (shelf life) of some expired before those could be consumed. Proactive stock management is another issue that often becomes responsible for pushing sales or sales at a reduced price, resulting in bulk buying. In addition, intelligent/innovative packaging (to help improve self-life and carry adequate information to facilitate all stakeholders) may also be useful in reducing FW, especially from retail and residential sectors.]