Apples are consumed lavishly worldwide, while demand is increasing for the management of the huge apple-waste amounts that lead to significant disposal costs and ecological issues. Additionally, apples represent fruits with several bioactive constituents, which are key factors in a healthy, balanced diet. In the present study, an extensive review is presented regarding the bioactive compounds of an apple processing by-product, namely apple pomace, mentioning their significance as viable ingredients/substances in foods and cosmetics aiming at chronic disease prevention and health promotion. Apple pomace contains several constituents, such as polar lipids, phenolics, vitamins and dietary fibers, with potential antioxidant, anti-inflammatory, anti-thrombotic, anti-aging and skin-protecting properties, and thus, they may contribute to minimizing the risk of various health conditions. Additionally, the mechanisms of action of such functional bioactives from apple pomace exert health benefits that will be examined, while the potential synergistic effects will also be investigated. Moreover, we will present the methods and techniques needed for the utilization of apple pomace in the appropriate form, such as powder, extracts, essential oil and so on, and their several applications in the food and cosmeceutical industry sectors, which summarize that apple pomace represents an ideal alternative to synthetic bioactive compounds.

Kefir-based fermentation products exhibit antioxidant and anti-inflammatory effects against oxidative stress, inflammation, platelet activation and aggregation, and other related manifestations, thereby preventing the onset and development of several chronic diseases. Specifically, water kefir, a symbiotic culture of various microorganisms used for the production of several bio-functional fermented products, has been proposed for its health-promoting properties. Thus, water kefir grains and its apple pomace-based fermentation beverage were studied for bioactive amphiphilic and lipophilic lipid compounds with antioxidant, antithrombotic, and anti-inflammatory properties. Total lipids (TL) were extracted and further separated into their total amphiphilic (TAC) and total lipophilic content (TLC), in which the total phenolic and carotenoid contents (TPC and TCC, respectively) and the fatty acid content of the polar lipids (PL) were quantified, while the antioxidant activity of both TAC and TLC were assessed in vitro, by the ABTS, DPPH, and FRAP bioassays, along with the anti-inflammatory and antithrombotic activity of TAC against human platelet aggregation induced by the thrombo-inflammatory mediator, platelet-activating factor (PAF) or standard platelet agonists like ADP.ATR-FTIR spectra facilitated the detection of specific structural, functional groups of phenolic, flavonoid, and carotenoid antioxidants, while LC−MS analysis revealed the presence of specific anti-inflammatory and antithrombotic PL bioactives bearing unsaturated fatty acids in their structures, with favorable omega-6 (n-6)/omega-3 (n-3)polyunsaturated fatty acids (PUFA), which further support the findings that the most potent antioxidant, anti-inflammatory and antithrombotic bioactivities were observed in the TAC extracts, in both water kefir grains and beverage cases. The detection of such bioactive components in both the uncultured water kefir grains and in the cultured beverage further supports the contribution of water kefir microorganisms to the bioactivity and the bio-functionality of the final fermented product. Nevertheless, the extracts of the beverage showed much stronger antioxidant, anti-inflammatory, and antithrombotic activities, which further suggests that during the culture process for producing this beverage, not only was the presence of bioactive compounds produced by kefir microflora present, but biochemical alterations during fermentation of bioactive components derived from apple pomace also seemed to have taken place, contributing to the higher bio-functionality observed in the apple pomace—water kefir-based beverage, even when compared to the unfermented apple pomace. The overall findings support further studies on the use of water kefir and/or apple pomace as viable sources of antioxidant, anti-inflammatory, and antithrombotic amphiphilic bioactive compounds for the production of novel health-promoting bio-functional fermented products.

The anti-inflammatory, antithrombotic and antioxidant effects of extracts from both apple juice and apple by-products (apple pomace) of organic cultured Greek Starking apples were evaluated in vitro. All extracts were separated in their total amphiphilic compounds (TACs) and total lipophilic compounds (TLCs) and assessed for their total phenolic content (TPC), total carotenoid content (TCC) and antioxidant activities (by the DPPH, ABTS and FRAP assays), as well as for their anti-inflammatory potency against the thrombo-inflammatory mediator, platelet activating factor (PAF) and their antithrombotic effects against a standard platelet-agonist (ADP) in human platelets. The rich-in-TAC extracts showed much higher content in phenolics and carotenoids than the TLC extracts, which was also reflected by the much stronger antioxidant capacities observed in TAC. ATR-FTIR spectroscopy revealed the presence not only of phenolics and carotenoids but also of amphiphilic polar lipids (PLs) in TAC, the structural analysis of which with LC–MS further revealed a fatty acid composition favorable for unsaturated fatty acids (UFAs) versus saturated ones (SFAs). The presence of such bioactive PLs that are rich in UFA within the TAC extracts of apple juice and apple pomace provide an explanation for the observed potent anti-inflammatory effects and antithrombotic properties of these extracts, mainly against the inflammatory pathway of PAF but also against platelet aggregation induced by ADP. Overall, these results further support the antioxidant, antithrombotic and anti-inflammatory potential of rich-in-TAC extracts from organic cultured apples and especially from their apple pomace by-products, which can further be utilized as sustainable bioactive ingredients in several functional products in a circular economy design.

Efficient use of agro-industrial residues is central to developing a circular bioeconomy. In this study, apple pomace was used as a feedstock for fermentation with water kefir cultures to investigate the formation of bioactive compounds and evaluate their functional biological effects. The effects of fermentation in a cement tank were compared to a reference fermentation system using a conventional glass vessel, focusing on physicochemical parameters and biological activity. Despite differences in pH evolution, no significant differences between the two fermentation systems were found in antioxidant capacity, total phenolic and carotenoid content, or inhibitory activity against platelet aggregation. Lipid extracts from both systems showed strong antioxidant properties and pronounced inhibitory activity against platelet-activating factor (PAF)- and ADP-induced aggregation, with significantly lower IC₅₀ values for PAF (p < 0.05), indicating enhanced anti-inflammatory specificity. These effects may be attributed to the synergistic interaction of fermentation-derived bioactives, including polar lipids, aglycone flavonoids, and carotenoids. Importantly, fermentation in a cement tank did not compromise biofunctional performance, highlighting its potential as a low-cost and scalable alternative for bioprocessing. Overall, these findings demonstrate that water kefir fermentation can efficiently convert low-value fruit residues into bioactive-rich matrices, providing a sustainable and environmentally friendly approach aligned with EU and UN circular economy frameworks for waste reduction and resource valorization.

Apple pomace is an abundant agro-industrial by-product rich in bioactive compounds. In the present study, amphiphilic bioactives from organic Greek Starking and Granny Smith apple pomace were recovered using a green extraction methodology, in compliance with EU legislations for food-grade solvents utilized in food stuffs, followed by evaporation of these solvents in vacuum conditions by flash rotary evaporation. The green extracts were then evaluated for their content in amphiphilic bioactives, as well as for their antioxidant photoprotective capacities spectrophotometrically, and for anti-inflammatory and potential in vitro antithrombotic activities by inhibiting human platelets’ aggregation. ATR-FTIR analysis revealed the presence of phenolics, carotenoids and polar lipids in these extracts. Thus, the total phenolic content (TPC) and total carotenoid content (TCC) were determined spectrophotometrically, while LC–MS analysis facilitated the characterization of specific polar lipid bioactives and quantified their fatty acid composition. Granny Smith extracts exhibited a higher phenolic content and enhanced anti-inflammatory and anti-platelet activities, likely associated with their polar lipid composition and low balanced ω6/ω3 fatty acid ratio, aligned with anti-inflammatory phenolic bioactives that are present in apple pomace. The observed inhibition of platelet aggregation, particularly via the PAF-related inflammatory pathways, suggests potential cardioprotective applications. Moreover, both extracts demonstrated potent antioxidant capacity by all the three mechanisms of action and UV photoprotective properties, probably due to the presence of both phenolic and carotenoid bioactives, with Starking showing stronger UVB-related activity and Granny Smith enhanced UVA-related protection, which—if combined with the observed potent antioxidant capacity and anti-PAF anti-inflammatory properties—further suggest potential applications in functional photoprotective and anti-aging cosmetic formulations. These findings highlight that apple pomace offers a sustainable source of amphiphilic bioactives suitable for nutraceutical and cosmetic applications.

This study explores the sustainable extraction, quantification, and functional evaluation of antioxidant amphiphilic (TAC) and lipophilic (TLC) compounds from avocado (Persea americana) products and by-products using green, solvent-efficient extraction, for potential applications in functional foods and/or cosmetics. Juice derived from organically grown domestic (Greek) avocado and the remaining juicing pulp by-products were subjected to a green extraction and partitioning fractionation process to obtain separately the extracted TLC and TAC. Quantitative analyses of total phenolic (TPC) and carotenoid contents (TCC), as well as antioxidant activity (DPPH, ABTS, FRAP), were performed using UV–Vis spectroscopy just after the extraction. ATR–FTIR spectroscopy was used to structurally characterize TAC bioactives compared to standards (gallic acid, quercetin, beta-carotene, soy phospholipids). TAC extracts exhibited higher TPC and superior antioxidant capacity across all assays, in comparison to the TLC, especially in the by-products. Despite relatively modest absolute phenolic and carotenoid concentrations compared to the literature, the extracts retained potent bioactivity, indicating selective enrichment of functional compounds. UV–Vis spectral peaks (240 nm, 310 nm) confirmed the presence of conjugated systems, suggesting potential for anti-UV photo-protective cosmetic applications. ATR–FTIR analysis further identified functional groups of key amphiphilic constituents, including simple phenolics, flavonoids, polyphenols, carotenoids and polar lipids. TAC extracts were successfully integrated into plant-based jelly prototypes as functional food supplements. Antioxidant stability of the jelly was retained for 15 days under refrigeration, though shelf-life limitations due to moisture and microbial growth highlight the need for preservative strategies. This work demonstrates a circular bioeconomy approach to food waste valorization, with significant implications for sustainable innovation in functional foods and clean-label cosmetics.