Apple waste can be transformed into functional and sustainable as well as natural ingredients in a circular economy. Researchers at the Micro4Food Lab at the Free University of Bozen/Bolzano have incorporated them into breads and dietary supplements, with very positive results. Attention will only have to come to the possible risk of transferring pesticide residues into the final product.
Apple waste goes back into production
The university research lab in Bolzano, Italy, subjected apple waste (peel and pulp residue) resulting from processing the fruit at the South Tyrolean company Pan Surgelati, a leading strudel producer, to simple fermentation with lactic acid bacteria.
Thus, a new natural, powdered ingredient is made for two different applications that are already well established in the scientific literature. (1) It can in fact be mixed with wheat flour to add functionality to bread, or included in the formula of a dietary supplement.
The super-bread and the supplement
The addition of the new natural ingredient from apple scraps gives the bread a higher fiber content and a more complex flavor profile, but also a better dough viscosity. Most importantly, better durability that is expressed in less susceptibility of the bread to becoming stale and suffering mold contamination.
The dietary supplement obtained using the same extract from apple scraps was analyzed by researchers using in vitro tests that simulate intestinal mucosa. ‘We found that phenolic compounds released during fermentation help counteract inflammatory processes and the effects of oxidative stress in cells and preserved the integrity of the intestinal mucosa. Now we would like to continue to test the effectiveness of this supplement in epidermal regeneration processes as well‘, explains microbiologist Raffaella Di Cagno, coauthor of the research with Marco Gobbetti, both professors at the Faculty of Science and Technology in Bolzano and directors of the Micro4Food Lab.
The value of apple waste
Apples represent the fruit with the highest percentage of processing waste (about 26 percent). The most common destinations for these by-products are animal feed, processing into biogas or composting to make biological fertilizer. Uses in tune with circular economy principles, which nevertheless disperse fiber, phytocompounds and minerals of primary value in human nutrition. Such as phenolic compounds (with antioxidant, anti-inflammatory, antimicrobial or cytotoxic virtues), as well as magnesium and calcium.
Nutritionally, apple waste has a very high content of dietary fiber (up to 93%), which exerts numerous beneficial health functions. The favorable interaction with the function of the intestinal microbiome, in particular, has beneficial effects on the intestinal epithelium and immune system. Proper dietary fiber consumption also improves weight management, lowers blood cholesterol, and controls glycemic and insulin responses.
The pesticide risk
So many properties make apple by-products a perfect example of circular economy and sustainability. Threatening its high potential value remains only, unfortunately, the risk of transferring any pesticide residues into the new ingredient.
Numerous investigations have shown the presence of pesticide residues in apples. One for all, the one conducted in 2015 for Greenpeace on 126 samples of apples: 83 percent of conventionally farmed fruits were found to be contaminated with residues, in 60 percent with multiple chemicals. With cocktail effect toxicity still unknown. (2) The risk can be eliminated at the root. Limiting only organic fruit waste to food reuse, the high road to progress.
Marta Strinati
Notes
1) The two Micro4Food Lab papers on the reuse of fermented apple scraps are.
– Cantatore V, Filannino P, Gambacorta G, et al. Lactic Acid Fermentation to Re-cycle Apple By-Products for Wheat Bread Fortification. Front Microbiol. 2019;10:2574. Published 2019 Nov 6. doi:10.3389/fmicb.2019.02574
– Tlais AZA, Da Ros A, Filannino P, Vincentini O, Gobbetti M, Di Cagno R. Biotechnological re-cycling of apple by-products: A reservoir model to produce a dietary supplement fortified with biogenic phenolic compounds [published online ahead of print, 2020 Jul 26]. Food Chem. 2020;336:127616. doi:10.1016/j.foodchem.2020.127616
2) On pesticide risk in apples, see. Matteo Garuti. Pesticides in apples: what are the health and environmental risks? The Food Journal
Professional journalist since January 1995, he has worked for newspapers (Il Messaggero, Paese Sera, La Stampa) and periodicals (NumeroUno, Il Salvagente). She is the author of journalistic surveys on food, she has published the book "Reading labels to know what we eat".
