Sustainable valorization of apple waste in a biorefinery: a bibliometric analysis

This bibliometric study explored the scientific publications of apple waste over the period from 2000 to 2020, aiming to contribute to the sustainable development of the apple industry toward waste-biorefinery implementation, advocating a circular economy. The bibliometric study covered the publications' evolution, research areas, top-cited papers, international collaborative networks, top countries and journals. The results demonstrate that 628 documents (604 articles and 24 reviews) studied apple waste over the last 20 years, and the number of publications exponentially increased after 2010. The most used keywords revealed that the main studied topics in the field were associated with technologies to manage apple pomace, the main solid waste generated from juice production, demonstrating a research trend toward renewable energy and bio-based products. The bibliometric study indicated that the most productive countries are China, India and the USA. Apple waste could be an environmentally friendly feedstock for biorefinery design and implementation. The biorefinery could produce value-added products (polyphenols, pectin, sugars and essential oils) and bioenergy (ethanol, methane, electricity and heat) in different industrial arrangements. The main technological routes described in the literature have been associated with the production of lactic acid, xylitol, ethanol, bioactive compounds, xyloglucan, films, pectin, acetic acid, acetone-butanol-ethanol, emulsifiers and inulinase enzyme. In conclusion, this review contributes to the decision-making for the industrial implementation of a waste biorefinery, advocating circular economy transition based on the sustainable valorization of apple waste. (c) 2022 Society of Chemical Industry and John Wiley & Sons, Ltd

Automated summary

This bibliometric study examined the scientific publications on apple waste from 2000 to 2020. The results indicate a significant increase in research on apple waste, particularly on technologies to manage apple pomace for renewable energy and bio-based products. China, India, and the USA are the most productive countries in this field.