(1) Background: Discarded young fig fruits (DYFFs) result in a waste of resources, such as sparse fruits and residual fruits, and there has been no research on the relationship between phenolic compounds and biological activity in DYFFs (2) Methods: Different deep eutectic solvents (DESs) and 80% ethanol were used to prepare DYFF extracts, and polyphenol extraction efficiency and bioactivities in the DYFFs extracts were compared. (3) Results: More than 1700 phytochemicals were identified in DYFFs, and thirteen of these typical phenolic compounds were analyzed quantitatively; chlorogenic acid, rutin, luteolin 8-C-glucoside, and epicatechin are the main polyphenols in DYFFs, especially chlorogenic acid with 2720–7980 mg/kg. Ferulic acid, caffeic acid, epicatechin, (+)-catechin, luteolin 8-C-glucoside, rutin, hesperetin, and chlorogenic acid showed different degrees of correlation with in vitro antioxidant activity. Moreover, the highest total phenol content found in the extracts of ChCl-Ethylene glycol (Choline chloride:Ethylene glycol = 1:2) was 8.88 mg GAE/g DW, and all quantitatively analyzed phenolic compounds had high levels in various DESs and 80% ethanol. The 80% ethanol and Choline chloride (ChCl) solvent system showed the greatest antioxidant properties, and the Choline chloride-Urea (Choline chloride: Urea = 1:2) extract of DYFFs exhibited the highest inhibitory activity. (4) Conclusions: DESs have demonstrated potential as promising green solvents, especially the ChCl solvent system, which facilitates the extraction of polyphenols.

Polysaccharides from Ficus carica L. (FCP) exert multiple biological activities. As a biological macromolecule, the available knowledge about the specific structures and mechanisms of the biological activity of purified ‘Brunswick’ fig polysaccharides is currently limited. In the present study, chemical purification and characteristics were identified via chemical and instrumental analysis, and then the impact of FCP on immunomodulation activity in vitro and in vivo was examined. Structural characteristics showed that the molecular weight of the FCP sample was determined to be 127.5 kDa; the primary monosaccharides present in the FCP sample were galacturonic acid (GalA), arabinose (Ara), galactose (Gal), rhamnose (Rha), glucose (Glc), and xylose (Xyl) at a ratio of 0.321:0.287:0.269:0.091:0.013:0.011. Based on the investigation of in vitro immunomodulatory activity, FCP was found to stimulate the production of NO, TNF-α, and IL-6, and increased the pinocytic activity of macrophages. Further analysis revealed that FCP activated macrophages by interacting with Toll-like receptor 4 (TLR4). Moreover, the in vivo test results indicate that FCP showed a significant increase in serum pro-inflammatory factors in immunosuppressed mice. Overall, this study suggests that FCP has the potential to be utilized as a novel immunomodulator in the pharmaceutical and functional food industries.

To upgrade the utilization of Syzygium samarangense in food industries, the key biological component, i.e., polysaccharide, was extracted from the fruit by alkaline treatment, and its structural characteristics, physicochemical properties, gelling properties and biological activities were investigated. The findings demonstrated that the alkaline-extracted S. samarangense polysaccharide (SSP-AK) predominantly exists as a pectic polysaccharide with a high rhamnogalacturonan-I domain. The monosaccharide composition primarily includes rhamnose, glucuronic acid, galacturonic acid, glucose, galactose, and arabinose. The molecular weight distribution of SSP-AK was characterized by two peaks, with fraction 1 exhibiting a high molecular weight of 7658 kDa and fraction 2 exhibiting a molecular weight of 345.3 kDa. Meanwhile, SSP-AK exhibited excellent rheological behavior and gelling properties upon Ca²⁺-induced gelation, which may be related to its relatively low degree of esterification of 41.3%. Further studies revealed that higher concentrations of pectin and Ca²⁺ led to the formation of stronger gels. The SSP-AK gels exhibited superior rheological properties, increased hardness, enhanced water-holding capacity, and a more compact network structure than the other gels. Moreover, SSP-AK exhibited significant in vitro antioxidant activity and immunomodulatory effects, including significantly enhancing the DPPH and ABTS radical-scavenging abilities and production of NO, IL-6, and TNF-α in RAW264.7 cell models. This study enhances the understanding of S. samarangense cell wall polysaccharides and may facilitate their application in the development of functional and health-oriented food products.

In order to upgrade the potential of cereal bran arabinoxylan for advanced hydrogel applications, a deep understanding of its gelation process is required. This work provides a comprehensive and systematic analysis of the laccase-catalyzed cross-linking of feruloylated arabinoxylan (FAX) to establish a clear link between processing conditions and final hydrogel properties. Endo-1,4-xylanase was used to obtain corn bran FAX rich in ferulic acid moieties, and then we demonstrated that gel formation is driven by the oxidative coupling of these feruloyl monomers into diferulic acid bridges, e.g., 8-5′, 5-5′, 8-O-4′, and 8-5′ benzofuran diferulic acids. A systematic investigation revealed that hydrogel properties were significantly affected by the processing conditions, i.e., FAX concentration, enzyme dosage, reaction pH, and reaction temperature during the enzymatic gel formation catalyzed by laccase. While gel strength peaked at a FAX concentration of 30 mg/mL, an optimal temperature of 25 °C and pH 6 were identified. Notably, we discovered a critical trade-off with enzyme concentration: higher laccase levels accelerated the reaction but compromised the final hydrogel’s mechanical strength and water retention. Gelation failed completely at pH ≥ 9 due to laccase inactivation. Meanwhile, scanning electron microscope analysis revealed that the microstructure of the FAX hydrogels was significantly affected by changes in the processing conditions. These findings offer crucial insights for the rational design of FAX-based hydrogels, enabling their tailored fabrication for food industry applications.

Mashed potatoes (MP) are widely consumed starch-based foods. However, their shelf life is limited by starch retrogradation during low-temperature storage, which causes texture hardening, water exudation, and sensory deterioration. Although natural polysaccharides can modulate starch properties, the specific anti-retrogradation effect of soluble arabinoxylan (AX) in complex MP matrices remains unknown. In this study, the effects of AX on the physicochemical and sensory qualities of MP during 7 d of storage at 4 °C were comprehensively investigated. Results demonstrated that AX significantly reduced the rheological moduli (i.e., G′ and G″ values) and hardness of stored MP. Additionally, LF-NMR, XRD, FTIR and SEM analyses, together with water holding capacity (WHC) measurement, revealed that AX improved water retention and restricted water mobility of the system, delayed starch recrystallization, inhibited the formation of short-range ordered structures, and physically disrupted the starch microstructure, thereby attenuating the overall starch retrogradation process. Moreover, the addition of AX helped maintain the sensory appeal of the products. These findings suggest that AX modulates the structural evolution of the starch matrix during storage. This distinguishes the present work from conventional hydrocolloid studies by demonstrating that AX can simultaneously inhibit starch retrogradation, stabilize color, and maintain soft texture. This work highlights the potential of AX as a clean-label multifunctional modifier to extend the shelf life of starchy convenience foods.

To utilize thinned young kiwifruit for potential industrial applications, this study compared structural properties and in vitro bioactivities of pectic polysaccharides isolated from three thinned young red-fleshed kiwifruit cultivars, including Actinidia chinensis cv. ‘Donghong’, ‘Hongshi’, and ‘Hongyang’. The results demonstrated that these young kiwifruit byproducts were rich in pectic polysaccharides, with extraction yields of 90.7–101.3 mg/g dry weight. Although their bound polyphenols (8.02–8.93 mg GAE/100 mg), esterification degrees (50.45–61.32 %), and molecular weights (7.44 × 10⁴–8.51 × 10⁴ Da) varied across cultivars, the glycosidic linkage patterns showed remarkable consistency, dominated by homogalacturonan (12.07–13.84 mol%) and rhamnogalacturonan-I (70.25–75.09 mol%) regions. Notably, all these pectic polysaccharides, particularly those isolated from the ‘Donghong’ cultivar, demonstrated notable antioxidant, antiglycation, prebiotic, and immunoenhancing activities in vitro. These findings indicate that thinned red-fleshed kiwifruit byproducts are rich sources of RG-I enriched pectic polysaccharides, with significant potential as functional food ingredients.