Natural Polyphenol Recovery from Apple-, Cereal-, and Tomato-Processing By-Products and Related Health-Promoting Properties

Abstract

Polyphenols of plant origin are a broad family of secondary metabolites that range from basic phenolic acids to more complex compounds such as stilbenes, flavonoids, and tannins, all of which have several phenol units in their structure. Considerable health benefits, such as having prebiotic potential and cardio-protective and weight control effects, have been linked to diets based on polyphenol-enriched foods and plant-based products, indicating the potential role of these substances in the prevention or treatment of numerous pathologies. The most representative phenolic compounds in apple pomace are phloridzin, chlorogenic acid, and epicatechin, with major health implications in diabetes, cancer, and cardiovascular and neurocognitive diseases. The cereal byproducts are rich in flavonoids (cyanidin 3-glucoside) and phenolic acids (ferulic acid), all with significant results in reducing the incidence of noncommunicable diseases. Quercetin, naringenin, and rutin are the predominant phenolic molecules in tomato by-products, having important antioxidant and antimicrobial activities. The present understanding of the functionality of polyphenols in health outcomes, specifically, noncommunicable illnesses, is summarized in this review, focusing on the applicability of this evidence in three extensive agrifood industries (apple, cereal, and tomato processing). Moreover, the reintegration of by-products into the food chain via functional food products and personalized nutrition (e.g., 3D food printing) is detailed, supporting a novel direction to be explored within the circular economy concept.

Phenolic Compounds from New Natural Sources—Plant Genotype and Ontogenetic Variation

“…Fresh fruits and vegetables represent a significant segment in the functional and nutritional food sector. In fruit and vegetable production and processing, unused parts of the plants remain, often containing significant amounts of bioingredients [ 64 , 65 , 66 , 67 ]. Fruits and vegetables include hulls, skins, pods, pomace, seeds and stems, which are usually discarded despite containing potentially beneficial compounds such as carotenoids, dietary fibre, enzymes and polyphenols ( Table 4 ).…”

“…Fruits and vegetables include hulls, skins, pods, pomace, seeds and stems, which are usually discarded despite containing potentially beneficial compounds such as carotenoids, dietary fibre, enzymes and polyphenols ( Table 4 ). The use of fruit and vegetable waste in food and pharmaceutical products is gaining importance [ 64 , 65 , 66 ]. Vaz et al [ 65 ] evaluated vegetable pomace residues (artichoke, red pepper, cucumber and carrot) for juice.…”

“…The production of juices, sauces, ketchup or purees produces significant quantities of by-products (peel, seeds, small amounts of pulp), increasing the cost of the primary products by 5–30%. The by-products contain PCs, including compounds with significant antioxidant and antimicrobial activities [ 66 ]. Blackcurrant buds and leaves are also excellent sources of beneficial PCs.…”

Vaccinium Species (Ericaceae): Phytochemistry and Biological Properties of Medicinal Plants

“…On the other hand, as the population is also increasing, and following recent trends regarding consumer preferences for organic, good-quality food products and healthy everyday living, the generated fruits are insufficient to provide the best quality of food globally [ 2 , 3 ]. Additionally, as fruit production increases, the generation of large quantities of by-products is inevitable [ 4 , 5 , 6 ]. Integrating these by-products into functional foods presents a promising alternative to reduce the generated waste and increase several foodstuffs’ nutritional quality [ 7 , 8 , 9 , 10 , 11 ].…”

Catechol-O-methyltransferase Inhibitors from Calendula officinalis Leaf

“…Although C. officinalis petals are used medicinally, the other parts of the plant are presently not utilized. Several recent studies have drawn attention to the effective use of waste- or by-products arising from productization processes [ 13 , 14 ]. Effective utilization of the currently unused parts of C. officinalis requires information on their chemical composition and biological activities.…”