The Sustainable Development Goals (SDGs) contribute to the improvement of production and consumption systems, hence, assisting in the eradication of hunger and poverty. As a result, there is growing global interest in the direction of economic development to create a zero-waste economy or circular economy. Citrus fruits are a major fruit crop, with annual global production surpassing 100 million tons, while orange and tangerine production alone account for more than half of the overall production. During pre- and postharvest stages of citrus fruit production, it is estimated that more than 20% of fruit biomass is lost, due, primarily, to biotic stresses. This review emphasizes causes of fruit losses by pathogenic caused diseases and proposes a bio-circular perspective in the production of citrus fruits. Due to substantial changes in fruit characteristics and environmental conditions, some of the most economically significant pathogens infect fruits in the field during the growing season and remain dormant or inactive until they resume growth after harvest. Peel biomass is the most significant by-product in citrus fruit production. This biomass is enriched with the value-adding essential oils and polysaccharides. For the complete bio-circular economy, these active ingredients can be utilized as citrus postharvest coating materials based upon their functional properties. The overall outreach of the approach not only reduces the amount of agricultural by-products and develops new applications for the pomology industry, it also promotes bio-circular green economic, which is in line with the SDGs for the citrus fruit industry.

Thailand is a prominent global producer of mangoes, providing a wide range of mango cultivars and dealing with the challenge of managing biomass. Thus, biorefining mango peel to extract valuable components has the potential to reduce organic waste and create a new revenue source for the mango processing sector. This study aims to examine the physiology, physiochemical, and chemical characteristics in peel of nine Thai mango cultivars, along with the relationship between their characteristics. The Thai mango cultivars Mahachanok, Chok anan, and Rad exhibited a yellow appearance, while the other six cultivars appeared yellow-green. However, the firmness of the fruit was directly correlated with the firmness of the pulp. A proximate composition study revealed that the predominant constituent of mango peel was carbohydrates, comprising up to 75% of its composition. This was followed by fibre, which accounted for up to 13%. The Nga mango had the highest levels of total phenolic content (220 mgGAE/g) and total flavonoid content (5.5 mgCE/g). The primary phenolic acids identified in Thai mango peel were epicatechin, caffeic acid, catechin, and gallic acid. The Mahachanok cultivar exhibited the highest antioxidant activity, as determined by the ABTS and DPPH assays, with values of 85.67% and 85.78%, respectively. This study demonstrated the connections between the physiochemical characteristics of mangoes and their chemical compositions in different cultivars, indicating the possibility of choosing particular cultivars for extracting targeted bioactive compounds. The multivariate analyses revealed that there was no correlation between the physiochemical and chemical profiles of mangoes. This study highlights the significance of mango peel as a valuable by-product that has significant environmental and economic ramifications for the mango processing industry.