This study aims to evaluate the interspecific variation in polyphenolic profiles and biological activities of acorn flours from three native Tunisian Quercus L. species (Q. ilex L., Q. suber L., and Q. canariensis Willd.). Q. canariensis extracts are the richest in total phenolic, flavonoid and hydrolysable tannin contents. Six phenolic compounds were identified by HPLC-DAD analysis. Chlorogenic acid was the dominant compound in Q. canariensis and Q. ilex acorns. Whereas in Q. suber, caffeic acid was the main component and, along with trans-ferulic acid, was exclusive to this species. Hyperoside was notably identified in Q. canariensis. The UHPLC-DAD-MS analysis of hydrolysable tannins revealed twelve compounds. Acorns of Q. canariensis and Q. suber were dominated by ellagitannins, whereas Q. ilex contained mainly gallotannins. To our knowledge, these compounds are identified for the first time in Tunisian acorns. Q. canariensis exhibited the strongest antioxidant potential with DPPH, ABTS and FRAP assays, as well as the highest antibiofilm and anti-α-amylase activities. All extracts inhibited ATCC pathogenic bacterial strains while largely sparing the beneficial probiotic Limosilactobacillus fermentum. This result indicates a selective antibacterial effect not previously reported for Quercus acorns. Q. canariensis may represent a potential source of functional food ingredient, nutraceuticals, and pharmaceuticals, which remains to be confirmed through in vivo investigations.
The tomato processing industry is among the most widespread food industries worldwide, generating residues that pose an important issue due to their abundance and the rising negative environmental impacts associated with waste. This paper summarizes potential products that can be obtained from these sources, with a focus on the production of a specific biopolymer, cutin, which has great potential as a food packaging material. It emphasizes the development of an integration proposal model for the biorefinery process of tomato pomace, in line with the zero-waste concept, by performing comparative techno-economic analysis (TEA) of two processing scenarios: (1) a biorefinery pathway that valorizes tomato pomace utilization by producing cutin and (2) an integrated process designed for the simultaneous production of cutin and phenolic antioxidants. The study identifies current research gaps and outlines strategic directions for potential integration pathways that can enhance not only the economic viability and profitability of the process but also its environmental benefits through more complete. The techno-economic analysis model for cutin extraction showed an internal rate of return (IRR) of only 2%, which is five times lower than the IRR achieved in our integrated model for cutin and phenolic compounds. Additionally, the payback time in the integrated approach improved significantly from 9.56 to 5.7 years. This paper assesses the potential of tomato pomace as a sustainable source for the production of high-value bioproducts that can economically justify investments in sustainable bioprocessing technologies and reduce waste through an integrated approach.
Heavy metal stress severely impairs global agricultural productivity, a challenge exacerbated by rising industrial activities. To mitigate chromium (Cr) toxicity in crops, this study evaluated the potential of seed priming with four distinct acids, ascorbic acid (AA), citric acid (CA), nitric acid (NA), and salicylic acid (SA), on broad bean (Vicia faba L.) seedlings exposed to 50 ppm Cr(VI). Cr(VI) exposure alone severely compromised development, reducing root and shoot fresh biomass by 47% and 52.3% and lengths by 60.8% and 62.19%, respectively. This growth inhibition was mirrored by a massive drop in total soluble sugars (over twofold in shoots and threefold in roots) and a twofold spike in toxic hydrogen peroxide (H2O2) accumulation. However, acidic priming agents effectively protected the seedlings from this oxidative crisis. The co-application of these effectors limited the inhibitory effects of Cr(VI), increasing biomass up to twofold and reducing H2O2 levels by around 32% in roots and 26% in shoots. This reduction in oxidative damage subsequently alleviated cellular stress, restoring protein content (by up to 70.72% in shoots under AA) and bringing catalase (CAT) and ascorbate peroxidase (APX) activities back toward baseline levels, reducing them by more than 50% compared to the unprimed Cr(VI) control. Notably, regarding bioaccumulation, only AA priming significantly limited heavy metal uptake, reducing chromium accumulation by 36.5% in roots and 26.5% in shoots. This unique protection is likely linked to a potential chemical reduction of mobile Cr(VI) near the root boundaries and the regulation of internal osmoprotectant systems. These findings suggest that seed priming with these effectors, especially AA, offers a highly scalable, low-cost, and sustainable strategy for enhancing crop tolerance in heavy-metal-polluted soils.
Olive leaves represent a metabolically active tissue that plays an important role in plant responses to biotic stress. The present study comprised two independent experiments investigating biochemical responses of olive leaves to bacterial and fungal challenge under controlled conditions. Changes in primary metabolites (sugars, organic acids and free amino acids), phenolic compounds and lipid peroxidation were analyzed using chromatographic and spectrophotometric methods. In the bacterial experiment, pronounced differences were observed in primary metabolism. Tryptophan concentrations ranged from approximately 50 mg kg-1 DW to more than 360 mg kg-1 DW in 'Istarska bjelica', while sucrose concentrations reached up to 87 g kg-1 DW, demonstrating cultivar-dependent differences in carbohydrate metabolism. Phenolic profiling showed that secoiridoids were the dominant phenolic class, with oleuropein concentrations exceeding 27 g kg-1 DW across bacterial treatments. In the fungal experiment, amino acids showed greater variability than sugars and phenolic compounds, whereas MDA concentrations ranged from approximately 190 to 300 nmol g-1 DW but did not differ significantly among pathogen treatments. Overall, the two experiments showed distinct patterns of metabolite variation associated with bacterial and fungal challenge. These findings contribute to a better understanding of cultivar-dependent metabolic responses and provide a basis for future studies of olive-microbe interactions.
Liverworts are often used as bioindicators of metals in the environment. Here, we evaluated the growth, metal uptake and ultrastructural responses of a model liverwort Marchantia polymorpha subsp. ruderalis to a concentration gradient of Zn, Cd and Pb derived from native metalliferous soil, in the absence of their aerial deposition. Thalli of M. polymorpha were cultivated from gemmae on substrates containing a Zn, Cd and Pb gradient, established by mixing metalliferous and non-metalliferous soils with comparable physicochemical characteristics. Biochemical, ionomic, elemental localisation and ultrastructural analyses were subsequently performed. Increasing soil Zn, Cd, Pb concentrations constrained thallus growth already within the first week of metal exposure and resulted in four- to fivefold reductions in biomass, accompanied by impaired photosynthetic performance, activation of stress-related defence mechanisms, decreased uptake of K, Mn and P, and increased accumulation of Ca, Fe, S, Zn, Cd and Pb. While Zn and Pb concentrations in thalli increased linearly with their substrate availability, a hyperaccumulation-like response was displayed for Cd. Concentration of Cd in thallus, however, remained well below the hyperaccumulation threshold established for vascular plants. Metals were sequestered in ventral thallus tissues, spatially separated from photosynthetically active parts, occurring alongside ultrastructural changes such as thickening of the ventral cuticle, chloroplast modifications, starch and plastoglobuli accumulation, and proliferation of electron-dense cytoplasmic vesicles. When grown across a soil metal gradient, M. polymorpha exhibits Zn- and Pb-indicator behaviour and previously undescribed Cd-accumulator behaviour, accompanied by reduced overall fitness. Hence, exposure to increasing substrate metal concentrations triggered a variety of physiological, ionomic and structural changes indicating this species is weakly tolerant to Zn, Cd and/or Pb taken up from the soil.
