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A waste-to-protein system that integrates a range of waste-to-protein upgrading technologies has the potential to converge innovations on zero-waste and protein security to ensure a sustainable protein future. We present a global overview of food-safe and feed-safe waste resource potential and technologies to sort and transform such waste streams with compositional quality characteristics into food-grade or feed-grade protein. The identified streams are rich in carbon and nutrients and absent of pathogens and hazardous contaminants, including food waste streams, lignocellulosic waste from agricultural residues and forestry, and contaminant-free waste from the food and drink industry. A wide range of chemical, physical, and biological treatments can be applied to extract nutrients and convert waste-carbon to fermentable sugars or other platform chemicals for subsequent conversion to protein. Our quantitative analyses suggest that the waste-to-protein system has the potential to maximise recovery of various low-value resources and catalyse the transformative solutions toward a sustainable protein future. However, novel protein regulation processes remain expensive and resource intensive in many countries, with protracted timelines for approval. This poses a significant barrier to market expansion, despite accelerated research and development in waste-to-protein technologies and novel protein sources. Thus, the waste-to-protein system is an important initiative to promote metabolic health across the lifespan and tackle the global hunger crisis., 40 pages, 5 figures. Supplementary materials can be accessed on request to corresponding author Miao Guo: miao.guo@kcl.ac.uk

Bread as a staple food has been predominantly prepared from refined wheat flour. The world’s demand for food is rising with increased bread consumption in developing countries where climate conditions are unsuitable for wheat cultivation. This reliance on wheat increases the vulnerability to wheat supply shocks caused by force majeure or man-made events, in addition to negative environmental and health consequences. In this review, we discuss the contribution to the sustainability of food systems by partially replacing wheat flour with various types of plant ingredients in bread making, also known as composite bread. The sustainable sources of non-wheat flours, their example use in bread making and potential health and nutritional benefits are summarized. Non-wheat flours pose techno-functional challenges due to significantly different properties of their proteins compared to wheat gluten, and they often contain off-favor compounds that altogether limit the consumer acceptability of final bread products. Therefore, we detail recent advances in processing strategies to improve the sensory and nutritional profiles of composite bread. A special focus is laid on fermentation, for its accessibility and versatility to apply to different ingredients and scenarios. Finally, we outline research needs that require the synergism between sustainability science, human nutrition, microbiomics and food science.

Brewers spent grain (BSG) is the main brewery industry by-product, with potential applications in the feed and food industries due to its carbohydrate composition. In addition, the lignocellulosic nature of BSG makes it an adequate substrate for carbohydrases production. In this work, solid-state fermentation (SSF) of BSG was performed with Aspergillus ibericus, a non-mycotoxin producer fungus with a high capacity to hydrolyze the lignocellulosic matrix of the agro-industrial by-products. SSF was performed at different scales to produce a crude extract rich in cellulase and xylanase. The potential of the crude extract was tested in two different applications: -(1) - the enzymatic hydrolysis of the fermented BSG and (2) - as a supplement in aquafeeds. SSF of BSG increased the protein content from 25% to 29% (w/w), while the fiber content was reduced to 43%, and cellulose and hemicellulose contents were markedly reduced to around 15%. The scale-up of SSF from 10 g of dry BSG in flasks to 50 g or 400 g in tray-type bioreactors increased 55% and 25% production of cellulase and xylanase, up to 323 and 1073 U g1 BSG, respectively. The optimum temperature and pH of maximal activities were found to be 55°C and pH 4.4 for xylanase and 50°C and pH 3.9 for cellulase, cellulase being more thermostable than xylanase when exposed at temperatures from 45°C to 60°C. A BoxBehnken factorial design was applied to optimize the hydrolysis of the fermented BSG by crude extract. The crude extract load was a significant factor in sugars release, highlighting the role of hydrolytic enzymes, while the load of fermented BSG, and addition of a commercial -glucosidase were responsible for the highest phenolic compounds and antioxidant activity release. The lyophilized crude extract (12,400 and 1050 U g1 lyophilized extract of xylanase and cellulase, respectively) was also tested as an enzyme supplement in aquafeed for European seabass (Dicentrarchus labrax) juveniles. The dietary supplementation with the crude extract significantly improved feed and protein utilization. The processing of BSG using biological treatments, such as SSF with A. ibericus, led to the production of a nutritionally enriched BSG and a crude extract with highly efficient carbohydrases capable of hydrolyzing lignocellulosic substrates, such as BSG, and with the potential to be used as feed enzymes with remarkable results in improving feed utilization of an important aquaculture fish species., This study was supported by the project “SPO3-Development of innovative sustainable protein and omega-3 rich feedstuffs for aquafeeds, from local agro-industrial by-products”, reference POCI-01-0145-FEDER-030377, funded by the European Regional Development Fund (ERDF) and Portuguese Foundation for Science and Technology (FCT) and by the strategic funding of the UIDB/04469/2020 unit. HF and CC were supported by grants SFRH/BD/131219/2017 and SFRH/BPD/114942/2016, respectively, from FCT, MCTES, FSE, and UE under the North Portugal Regional Operational Program (NORTE 2020). José Manuel Salgado was supported by the grant CEB/N2020—INV/01/2016 from Project “BIOTECNORTE—Underpinning Biotechnology to foster the north of Portugal bioeconomy” (NORTE-01-0145-FEDER-000004)., info:eu-repo/semantics/publishedVersion

Correction: Volume13, Issue 8 Page: 4770-4770 DOI: 10.1039/d2fo90028a Published: APR 20 2022 Birch-derived glucuronoxylan (GX)-rich hemicellulose extract is an abundantly available by-product of the forest industry. It has multifunctional food stabilizing properties, and is rich in fiber and polyphenols. Here, we studied its effects on colonic metabolism and gut microbiota in healthy rats. Male and female Wistar rats (n = 42) were fed AIN-93G-based diets with 10% (w/w) of either cellulose (control), a polyphenol and GX-rich extract (GXpoly), or a highly purified GX-rich extract (pureGX) for four weeks. Both the GXpoly and pureGX diets resulted in changes on the gut microbiota, especially in a higher abundance of Bifidobacteriaceae than the cellulose containing diet (p < 0.001). This coincided with higher concentrations of microbial metabolites in the luminal contents of the GX-fed than control rats, such as total short-chain fatty acids (SCFAs) (p < 0.001), acetate (p < 0.001), and N-nitroso compounds (NOCs) (p = 0.001). The difference in the concentration of NOCs was not seen when adjusted with fecal weight. GX supplementation supported the normal growth of the rats. Our results indicate that GXpoly and pureGX can favorably affect colonic metabolism and the gut microbiota. They have high potential to be used as prebiotic stabilizers to support more ecologically sustainable food production.