Plant-derived biostimulant as priming agents enhanced antioxidant and nutritive properties in brassicaceous microgreens.

BACKGROUND: Microgreens constitute dietary sources of bioactive compounds imparting numerous health benefits and enhancing sensory experience. They can be successfully cultivated in soilless systems where biostimulants can be easily integrated as seed-priming and post-germination agents improving the sustainability of a crop's final production. Compared to an untreated control, three priming agents (a commercial legume-derived protein hydrolysate (A250), a novel protein hydrolysate derived from peanut biomass (H250) and hydropriming (H2O)) were applied to Komatsuna and Mibuna seeds grown as microgreens and compared for their effects on yield parameters, mineral composition, ABTS and FRAP antioxidant capacity, carotenoid concentration and phenolic compounds. RESULTS: Significant effects of the main experimental factors and their interactions were identified on antioxidant capacity. Compared to the control and hydropriming, the highest ABTS and FRAP values were observed in Mibuna with the A250 and H250 treatments, respectively. Additionally, the H250 treatment increased the total concentrations of phenolic acid derivatives and flavonoid derivatives in Mibuna and Komatsuna, in tune with the levels of total flavonoids. Concerning mineral composition, the highest concentrations in both species were those of phosphorus and nitrate. CONCLUSION: These results highlight the potential of select plant-based biostimulants as priming agents to enhance the antioxidant capacity, nutrient content and bioactive compound content, thus further increasing their functional and nutritive quality. In the light of this, the possibility of reducing the application of fertilizers by promoting a green transition for the intensive production of microgreens could subsequently be evaluated. © 2024 Society of Chemical Industry.

Chemical Eustress Elicits Tailored Responses and Enhances the Functional Quality of Novel Food Perilla frutescens.

Consumer demand for fresh and functional horticultural products is on the rise. Perilla frutescens, L. Britt (Lamiaceae) is a potential specialty/niche crop for consumption and therapeutic uses with high contents of phenolic and volatile compounds. Plant growth, mineral composition, polyphenol profile and aroma volatile components of two perilla genotypes in response to salinity (non-salt control, 10, 20 or 30 mM NaCl) applied as chemical eustressor were assessed. Salinity suppressed growth and yield of both genotypes, although the red-pigmented genotype was less sensitive than the green-pigmented one. Mild (10 mM NaCl) and moderate (20 and 30 mM NaCl) salinity suppressed foliar potassium, magnesium, nitrate and chlorophyll a concentrations of both genotypes and increased the levels of rosmarinic acid, total polyphenols and target aroma volatile components. Green perilla showed higher yield and biomass production and higher content of protein, dry matter, calcium, magnesium, perilla ketone and cis-jasmone, whereas red perilla exhibited higher content of potassium, chlorophyll a, rosmarinic acid, total polyphenols, perilla aldehyde and benzaldehyde. Our findings support that chemical eustressors such as mild to moderate salinity offer valuable means to manipulate phytochemical and aroma profiles.

Macronutrient deprivation eustress elicits differential secondary metabolites in red and green-pigmented butterhead lettuce grown in a closed soilless system.

BACKGROUND: Through precise control of the nutrient solution (NS), closed soilless systems enable targeted manipulation of plant secondary metabolites, which constitute health-promoting components of the human daily diet. A nutrient film technique (NFT) system was employed to assess the effect of NS macronutrient-based concentration (full, half-, and quarter-strength corresponding to electrical conductivity (EC) of 1.5, 0.75, and 0.5 dS m-1 ) on the bioactive profile of red and green-pigmented Salanova® butterhead lettuce. RESULTS: Half-strength NS reduced fresh biomass of both cultivars by 14%, whereas quarter-strength NS reduced the fresh biomass of green and red Salanova by 24% and 38%, respectively. However, moderate nutrient stress (half-strength NS) boosted red Salanova total ascorbic acid, chlorogenic, chicoric, caffeoyl-meso-tartaric, total phenolic acids, and anthocyanins concentrations by 266%, 199%, 124%, 251%, 162%, and 380%, respectively compared with the control, full-strength NS. CONCLUSIONS: Nutritional eustress and appropriate cultivar selection are effective means to increase phytochemical content and optimize year-round production of lettuce in closed soilless systems. © 2019 Society of Chemical Industry.

Configuration of watermelon fruit quality in response to rootstock-mediated harvest maturity and postharvest storage.

BACKGROUND: The configuration of watermelon fruit quality was analysed in a multi-factorial approach accounting for the effects of grafting, harvest maturity and postharvest storage. Diploid, seeded, hybrid cv. Pegasus, cultivated as scion on interspecific hybrid squash rootstock TZ148 and as non-grafted control, was stored at 25 °C following sequential harvests from the onset of ripening to over-maturity. RESULTS: Delayed rootstock-mediated climax in pulp lycopene and chroma was observed, while both were heightened by postharvest storage when harvest preceded full maturity. Pulp firmness was increased by 46.5% on TZ148, while postharvest decrease in firmness was non-significant. Non-grafted fruits attained their peak in pulp carbohydrate content earlier during ripening. Monosaccharide content declined and sucrose content increased both preharvest and postharvest; overall sugar content declined by 4.3% during storage. Pulp acidity decreased steadily with ripening but was moderately increased by grafting. Citrulline content increased by 12.5% on TZ148; moreover, it climaxed with ripening and declined with storage only in grafted fruit. CONCLUSION: Grafting enhances pulp texture and bioactive composition. Potential suppression of sugar content as a result of grafting is minimized at full commercial maturity. Brief postharvest ambient storage enhances pulp lycopene and chroma, especially in early-picked fruit, notwithstanding the depletion of monosaccharides and citrulline and a limited deterioration of texture. © 2015 Society of Chemical Industry.

Linking Colorimetric Variation with Non-Volatile and Volatile Components of Carob Flour.

Chromatic variation was examined for its association with flour composition and quality. Carob samples from variable altitudes and genetic backgrounds were milled and assessed for colorimetric parameter L* (lightness) and analyzed for phenols, tannins, antioxidant capacity, soluble carbohydrates (HPLC-RID), organic acids and protein (IC-CD), and volatile organic compounds (VOCs; HS-SPME/GC-MS). Higher altitudes and grafted genotypes yielded lighter-colored flours of higher antioxidant potential, phenols, tannins, sucrose, and malic acid concentrations. VOCs were mainly acids, esters, aldehydes, ketones, and alcohols. Acids were the most abundant and correlated negatively with L*, though correlation for many individual acids was non-significant, including 2-methyl-propanoic acid, widely considered the carob signature aroma (cheesy acidic buttery). The compositional and quality indexing potential of L* is more robust for grafted than non-grafted material, owing putatively to a narrower genetic basis. Antioxidant capacity and concentrations of phenolics, tannins and sucrose correlated positively with L*, indicating increased levels in carob flours sourced from grafted trees at higher altitudes. These flours also have a lower content of reducing sugars, the implication of which in the darkening of carob flour warrants further investigation. Overall, L* constitutes a reliable index for ranking carob flours for key compositional attributes and may be further reinforced by multiple-year data.

Zinc biofortification of Genovese basil: Influence on mineral profile and estimated daily intake in adults and children.

Despite the well-known beneficial function of Zn in human health, its deficiency is an increasingly recognized worldwide concern. In this work, we evaluated the agronomic biofortification of two basil (Ocimum basilicum L.) cultivars ('Aroma 2' and 'Eleonora') using nutrient solutions with different Zn concentrations (0, 12.5, 25, 37.5, and 50 µM). We focused on the impact of biofortification on the mineral profile quantified by ICP OES. Compared to the control, biofortification treatments increased Zn concentration by 22.03 % (on average). Consumption of one serving of 50 µM of Zn biofortified basil 'Aroma 2' guarantees an estimated daily intake (EDI) of 275.746 and 91.915 µg day-1 in adults and children, respectively. Furthermore, Zn biofortification positively affected the mineral profile of the leaves. Compared to the control, the B50 dose of Zn (50 µM of Zn) increased the EDI of macro and microelements in adults and children. This aspect highlights how biofortified basil consumption would improve consumers' nutritional status.

Iodine-Biofortified Microgreens as High Nutraceutical Value Component of Space Mission Crew Diets and Candidate for Extraterrestrial Cultivation.

The success of Space missions and the efficacy of colonizing extraterrestrial environments depends on ensuring adequate nutrition for astronauts and autonomy from terrestrial resources. A balanced diet incorporating premium quality fresh foods, such as microgreens, is essential to the mental and physical well-being of mission crews. To improve the nutritional intake of astronaut meals, two levels of potassium iodide (KI; 4 µM and 8 µM) and an untreated control were assessed for iodine (I) biofortification, and overall nutraceutical profile of four microgreens: tatsoi (Brassica rapa L. subsp. narinosa), coriander (Coriandrum sativum L.), green basil, and purple basil (Ocimum basilicum L.). A dose-dependent increase in I was observed at 8 µM for all species, reaching concentrations of 200.73, 118.17, 93.97, and 82.70 mg kg-1 of dry weight, in tatsoi, coriander, purple basil, and green basil, respectively. Across species, I biofortification slightly reduced fresh yield (-7.98%) while increasing the antioxidant activity (ABTS, FRAP, and DPPH). LC-MS/MS Q extractive orbitrap analysis detected 10 phenolic acids and 23 flavonoids among microgreen species. The total concentration of phenolic acids increased (+28.5%) in purple basil at 8 µM KI, while total flavonoids in coriander increased by 23.22% and 34.46% in response to 4 and 8 µM KI, respectively. Both doses of KI increased the concentration of total polyphenols in all species by an average of 17.45%, compared to the control.

Salt-Induced Stress Impacts the Phytochemical Composition and Aromatic Profile of Three Types of Basil in a Genotype-Dependent Mode.

Basil (Ocimum basilicum L.) is among the most widely used aromatic plants of Lamiaceae, often grown in areas where salinity is an adverse factor. Most studies on the effect of salinity on basil focused on the influence of salt stress on productive traits, while few reported on how it affects the phytochemical composition and the aroma profile. Three basil cultivars (Dark Opal, Italiano Classico, and Purple Ruffles) were grown hydroponically for 34 days with two nutrient solutions that differed in NaCl concentration [no NaCl (Control) and 60 mM NaCl]. Yield, secondary metabolite concentration (ß-carotene and lutein), antioxidant activity [1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferric reduction antioxidant power (FRAP)], and aroma profile based on composition of volatile organic compounds (VOCs) were appraised in response to salinity applications. Salt stress significantly reduced fresh yield in Italiano Classico and Dark Opal by 43.34 and 31.69%, respectively, while no effect was observed in Purple Ruffles. Furthermore, the salt-stress treatment increased ß-carotene and lutein concentrations, DPPH, and FRAP activities, and the total nitrogen content of the latter cultivar. CG-MS analysis revealed significant differences in VOCs composition of the basil cultivars, with Italiano Classico and Dark Opal characterized by the predominance of linalool (average 37.52%), which, however, was negatively affected by salinity. In Purple Ruffles, the predominant VOC compound, estragole (79.50%), was not affected by the deleterious effects of NaCl-induced stress.

Morpho-Physiological and Biochemical Responses of Hydroponically Grown Basil Cultivars to Salt Stress.

Depending on duration and magnitude, abiotic stresses interfere with plant metabolic processes and may severely impact developmental and qualitative attributes. In this study, in addition to characterizing three different cultivars of basil ('Anise', 'Cinnamon', and 'Lemon') grown under hydroponics, we appraised the impact of NaCl salt stress (60 mM) on morphophysiological and nutraceutical properties of the basil crop. Salt stress significantly reduced fresh yield (51.54%, on average) and photosynthetic parameters (ACO2, E, and gs) in all cultivars by raising tissue concentrations of Na+ and Cl-. In addition to reducing the concentration of nitrate (77.21%), NaCl salt stress increased the concentrations of key bioactive molecules, notably carotenoids (lutein and ß-carotene), phenolic acids, and flavonoid derivatives, thus resulting in a higher antioxidant activity of salt-treated basil plants compared to the untreated ones. Analysis by UHPLC revealed that cichoric acid was the most abundant polyphenolic compound in all basil cultivars, with the highest values recorded in 'Cinnamon'.

Biostimulatory Action of Vegetal Protein Hydrolysate Compensates for Reduced Strength Nutrient Supply in a Floating Raft System by Enhancing Performance and Qualitative Features of "Genovese" Basil.

The floating raft constitutes a valuable system for growing herbs as it effectuates high yield and prime functional quality. However, the pressing need for advancing sustainability in food production dictates the reduction of chemical fertilizer inputs in such intensive production schemes through innovative cultivation practices. In this perspective, our work appraised the productive and qualitative responses of two "Genovese" basil genotypes (Eleonora and Italiano Classico) grown in a floating raft system with nutrient solutions of varied electrical conductivity (EC; 2 and 1 dS m-1) combined with root application of protein hydrolysate biostimulant at two dosages (0.15 and 0.3 0 ml L-1 of Trainer®). The phenolic composition, aromatic profile, and antioxidant activities (ABTS, DPPH, and FRAP) of basil were determined by UHPLC/HRMS, GC/MS, and spectrophotometry, respectively. "Eleonora" demonstrated higher number of leaves (37.04 leaves per plant), higher fresh yield (6576.81 g m-2), but lower polyphenol concentration (1440.81 µg g-1 dry weight) compared to "Italiano Classico." The lower EC solution (1 dS m-1) increased total phenols (+32.5%), ABTS, DPPH, and FRAP antioxidant activities by 33.2, 17.1, and 15.8%, respectively, and decreased linalool relative abundance by 5.5%. Biostimulant application improved crop performance and increased total phenolic concentration in both genotypes, with the highest phenolic concentration (1767.96 µg g-1 dry weight) registered at the lowest dose. Significant response in terms of aromatic profile was detected only in "Eleonora." Our results demonstrate that the application of protein hydrolysate may compensate for reduced strength nutrient solution by enhancing yield and functional quality attributes of "Genovese" basil for pesto.

Differential Response to NaCl Osmotic Stress in Sequentially Harvested Hydroponic Red and Green Basil and the Role of Calcium.

Basil (Ocimum basilicum L.) is a heterogeneous reservoir of bioactive compounds that provide recognized benefits to human health, rendering it a model aromatic herb. Notwithstanding the application of nutritional stress, such as sodium chloride (NaCl) salinity, which mainly affects the primary metabolism, it also triggers adaptive mechanisms that involve the production of bioactive secondary metabolites. Genotype selection and the exogenous application of calcium chloride (CaCl2) help minimize salinity's suppressive effects on growth. In the present study, we hypothesize that the ratio of different salt types may induce differential responses in the function of preharvest factors in hydroponic basil culture. In this perspective, the stock nutrient solution (Control) was supplemented with 12.5 mm NaCl + 8.33 mm CaCl2 (Moderate Mix), 25 mm NaCl (Moderate NaCl), 25 mm NaCl + 16.66 of CaCl2 (High Mix), or 50 mM of NaCl (High NaCl) with the objective of evaluating the different impact of salinity on yield, sensory quality (color and aroma profile), and the accumulation of minerals and bioactive compounds in two successive harvests of green and red basil cultivars. Although more productive (+39.0% fresh weight) than the red one, the green cultivar exhibited higher susceptibility to salinity, especially under the High Mix and High NaCl treatments. The addition of CaCl2 to the High Mix solution reduced the sodium by 70.4% and increased the total polyphenols by 21.5% compared to the equivalent isomolar solution (High NaCl). The crop performance in terms of fresh and dry yield improved for both cultivars at the second cut. Regardless of cultivar and salt treatment, successive harvests also increased the concentration of phenols and vitamin C (29.7 and 61.5%, respectively) while reducing (-6.9%) eucalyptol, the most abundant aromatic compound in both cultivars. Salinity, as well as the mechanical stress induced by cutting, improved the functional quality of basil. However, the productive responses to the conditions imposed in our work once again highlighted the importance of genetic background. Specifically, CaCl2 in the Moderate Mix solution preserved fresh leaf weight in the most stress-sensitive green cultivar.

Nutritive and Phytochemical Composition of Aromatic Microgreen Herbs and Spices Belonging to the Apiaceae Family.

Microgreens represent a new generation of food products, commonly used to garnish and embellish culinary dishes, and recently associated with an increasing interest in their nutraceutical and phytochemical profiles. Four Apiaceae species: Pimpinella anisum L. (anise), Anthriscus cerefolium L. (chervil), Carum carvi L. (caraway), and Anethum graveolens L. (dill) were assessed for fresh yield, macro- and microminerals, total chlorophylls, total ascorbic acid, carotenoids, polyphenols, and their antioxidant activity. Anise was the species yielding the most (2.53 kg m-2) and having the highest lutein content (18.4 µg g-1 dry weight (DW)). Chervil and dill were characterized by the highest total ascorbic acid content (~151 mg AA g-1 fresh weight (FW)). The phenolic profile highlighted the presence of five flavonoid derivatives and 12 phenolic acid derivatives, with quinic acid derivatives being the most abundant phenols in the species tested. In addition, anise, caraway, and dill proved to be considerably rich in total polyphenols (~11056 µg g-1 DW). Caraway and dill were characterized by the highest antioxidant activity measured by the DPPH and ABTS methods, whereas the FRAP method revealed caraway as having the highest antioxidant activity. Such results highlight the potential of Apiaceae species as an alternative to other families which are commonly used for microgreens production.

Hemp microgreens as an innovative functional food: Variation in the organic acids, amino acids, polyphenols, and cannabinoids composition of six hemp cultivars.

Hemp (Cannabis sativa L.) is a multi-functional crop cultivated for fiber, seeds, or phytochemical extraction. Once a major industrial crop in several agro-environments, its cultivation strongly declined in developed countries since World War II. Exploiting hemp vegetative tissue as innovative food has remained largely unexplored. The current work examined the potential production of hemp microgreens. Six cultivars were assessed for yield and composition of organic acids, amino acids, polyphenols and phytocannabinoids, through IC, FLD-HPLC and UHPLC-HRMS, respectively. Bioactive composition was strongly related to the hemp variety. 'Silvana' demonstrated the highest total content of amino acids and essential amino acids, high concentrations of cannflavin A and B, and moderate levels of cannabidiol and cannabigerol. 'Finola' distinguished by the highest concentration of cannflavins and total polyphenols, and the lowest levels of Δ9-THC. Regardless of varietal differences, hemp microgreens proved widely safe in terms of Δ9-THC content.

Mapping the Primary and Secondary Metabolomes of Carob (Ceratonia siliqua L.) Fruit and Its Postharvest Antioxidant Potential at Critical Stages of Ripening.

Six critical stages corresponding to major morphophysiological events in carob fruit ripening were defined, and changes in the primary and secondary metabolome and in vitro antioxidant capacity were examined in two genotypes collected at low (15 m) and high (510 m) altitudes from genetically identified and georeferenced trees. Soluble carbohydrates were analyzed by HPLC-RI, macro-minerals by ion chromatography coupled to conductivity detection and polyphenols by UHPLC-Q-Orbitrap-HRMS. spectroscopy facilitated assays for condensed tannins and in vitro free-radical scavenging capacity of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferric-reducing antioxidant power (FRAP). The fruit respiration rate and moisture content declined sharply during the transition from the breaker to green pedicel stage. Sugar accumulation spiked at the onset of fruit coloration and culminated at 498.7 ± 8.4 mg g-1 dry weight (dw) in the late ripe stage, while the ratio of reducing sugars to sucrose decreased from 3.45 ± 0.32 to 0.41 ± 0.02. The total phenolic compounds and condensed tannins declined with ripening, particularly during the transition from the breaker to green pedicel stage. Eighteen polyphenols were identified and quantitated, with catechins and hydrolyzable tannins being dominant until the onset of fruit coloration. The transition to the green pedicel stage signaled a precipitous decline (90.9%) in catechins, hydrolyzable tannins (60.2%) and flavonol glycosides (52.1%) concomitant to the rise in gallic acid, which was putatively fueled by the enzymatic hydrolysis of gallotannins in immature fruit. Catechins, hydrolyzable tannins and flavone glycosides were more abundant at higher altitudes and gallic acid at lower altitudes. An antioxidant capacity was also favored by higher elevations and declined with ripening, particularly after the breaker stage. Correlations with FRAP and DPPH assays were significant for the total phenolic content, condensed tannins, catechins and hydrolyzable tannins. The highest correlation factors were obtained for epigallocatechin-gallate (r = 0.920 and r = 0.900; p < 0.01). Although the sharp drop in hydrolyzable and nonhydrolyzable tannins and catechins compromised the in vitro antioxidant capacity at physiological maturity, it also reduced the astringency and configured a palatable organoleptic fruit profile. These changes unraveled significant episodes in the ripening-related secondary metabolism of the carob fruit. They further highlighted the value of immature carob as a potent source of gallotannins, with putative in vivo anti-inflammatory action, and of catechins beneficial in preventing and protecting against diseases caused by oxidative stress.

Configuration of the Volatile Aromatic Profile of Carob Powder Milled From Pods of Genetic Variants Harvested at Progressive Stages of Ripening From High and Low Altitudes.

Carob powder is increasingly valued as a substitute for cocoa and as a flavor-enhancing component of processed foods. However, little is known about the impact of preharvest factors such as fruit maturity, genotype and altitude on its volatile organic compounds (VOCs) composition. The current study examined the VOCs composition of powder milled from pods of two genotypes cultivated at 15 and 510 m altitude and harvested at six progressive stages of maturity, ranging from fully developed immature green (RS1) to late ripe (RS6). Fifty-six VOCs categorized into acids, esters, aldehydes, ketones, alcohols, furans, and alkanes were identified through HS-SPME GC-MS analysis. Maturity was the most influential factor, followed by altitude and least by genotype. Aldehydes and alcohols correlated positively (r = 0.789; p < 0.001), both accumulated in immature carobs and decreased with progressive ripening, resulting in the attenuation of green grassy aroma. Conversely, acids increased with ripening and dominated the carob volatilome at full maturity, correlating negatively with aldehydes and alcohols (r = -0.835 and r = -0.950, respectively; p < 0.001). The most abundant VOC throughout ripening (17.3-57.7%) was isobutyric acid, responsible for the characteristic cheesy-acidic-buttery aroma of carob powder. The pleasurable aroma detected at the immature stages (RS2 and RS3) was traced to isobutyrate and methyl isobutyrate esters, rendering unripe green carob powder a potential admixture component for improving the aroma of novel food products. Lower altitude favored the accumulation of acids linked to less pleasant aroma, whereas isobutyric acid was more abundant at higher altitude. This constitutes a significant indication that higher altitude enhances the characteristic carob-like aroma and sensory quality of carob powder.

Changes in the primary and secondary metabolome of male green asparagus (Asparagus officinalis L.) as modulated by sequential harvesting.

Rising temperature and solar radiation drive the mobilization and depletion of crown-deposited metabolites harnessed for asparagus spear regeneration during the spring harvest season. We presently examined how successive same-season harvests impact the sensory, nutritive and bioactive composition of select green asparagus genotypes. Soluble carbohydrates were analyzed by HPLC-RI, organic acids and polyphenols by HPLC-DAD and metals by ion chromatography. Higher sugars and lower acids accentuated sweetness and lower polyphenols contributed to reduced astringency at the beginning of the harvest season. This trend was reversed as the season advanced and spear sensory quality was compromised by declining sugars and rising acids; however, functional quality improved as antioxidant capacity increased along with the concentrations of quercetin-3-O-rutinoside (rutin) and ascorbic acid. The compositional changes presently described were uniform across all genotypes examined and thus contribute toward our understanding of seasonal variation in the sensory and functional quality of this acclaimed health-promoting product.

Preharvest Nutrient Deprivation Reconfigures Nitrate, Mineral, and Phytochemical Content of Microgreens.

While imparting gastronomic novelty and sensory delight, microgreens also constitute rudimentary leafy greens packed with nutrients and phytochemicals. As such, they comprise an upcoming class of functional foods. However, apart from bioactive secondary metabolites, microgreens also accumulate antinutritive agents such as nitrate, especially under conducive protected cultivation conditions. The current work examined nutrient deprivation before harvest (DBH), applied by replacing nutrient solution with osmotic water for six and twelve days, as a strategy for reducing microgreen nitrate levels in different species (lettuce, mustard, and rocket). The three species were sown on a peat-based substrate, cultivated in a controlled climate chamber, and harvested 18 days after sowing, when the first two true leaves emerged. DBH impact on major constituents of the secondary metabolome, mineral content, colorimetric, and yield traits was appraised. Nitrate and mineral content were determined through ion chromatography, phenolic composition through UHPLC-Q-Orbitrap HRMS, and carotenoid composition through HPLC-DAD. Nutrient deprivation was effective in reducing nitrate content; however, effective treatment duration differed between species and decline was more precipitous in nitrate hyperaccumulating species such as rocket. Quercetin and kaempferol glycosides were the flavonol glycosides most abundant in brassicaceous microgreens, whereas lettuce microgreens were steeped in caffeoyl quinic acid. DBH interacted with species as it increased the total phenolic content of lettuce, decreased that of rocket, but did not affect mustard. Further research to link changes in phenolic composition to the sensory and in vivo bioactive profile of microgreens is warranted. Notably, brief (≤6 days) DBH can be applied across species with moderate or no impact on the phenolic, carotenoid, and mineral composition of microgreens. Brief DBH applications also have limited impact on microgreens' yield and colorimetric traits hence on the commercial value of the product. They can therefore be applied for reducing microgreen nitrate levels without significantly impacting key secondary metabolic constituents and their potential bioactive role.

Genotype and Successive Harvests Interaction Affects Phenolic Acids and Aroma Profile of Genovese Basil for Pesto Sauce Production.

Basil (Ocimum basilicum L.) is an essential ingredient of the Mediterranean cuisine due to its distinctive aroma. Genovese basil leaves are used to prepare "pesto", a condiment that has always caught the interest of consumers and producers. Usually, basil for industrial processing is harvested more than once to extract a higher yield. However, successive cuts can affect quality traits that play a crucial role in defining the product's final sensory profile. This research was aimed to evaluate the impact of cut on the quantitative and qualitative properties of three Genovese basil cultivars (Aroma 2, Eleonora and Italiano Classico) grown in an open field. Nitrate content, phenolic acids and aromatic profile were determined by ion chromatography (IC), high-performance liquid chromatography (HPLC), and gas chromatography coupled to a mass spectrometer (GC/MS) analysis, respectively. The second harvest increased fresh biomass and total phenolic acids content by 172% and 413%, respectively, with Italiano Classico recording the highest values. The combination of second-cut Aroma 2 yielded the lowest nitrate (473.8 mg kg-1 of fresh weight) and Eugenol (2.4%) levels. In the second harvest, Eleonora showed an increase in eugenol and trans-α-bergamotene of 75.3% and 48.2%, respectively; whereas, eucalyptol and ß-cis-ocimene decreased by 34.4% and 51.6%, respectively. Although successive harvests may increase basil yield and quality overall, the cultivar-dependent response to successive cuts needs to be accounted for in order to accomplish standardization of industrial "pesto" sauce.

Ontogenetic Variation in the Mineral, Phytochemical and Yield Attributes of Brassicaceous Microgreens.

Microgreens constitute novel gastronomic ingredients that combine visual, kinesthetic and bioactive qualities. The definition of the optimal developmental stage for harvesting microgreens remains fluid. Their superior phytochemical content against mature leaves underpins the current hypothesis of significant changes in compositional profile during the brief interval of ontogeny from the appearance of the first (S1) to the second true leaf (S2). Microgreens of four brassicaceous genotypes (Komatsuna, Mibuna, Mizuna and Pak Choi) grown under controlled conditions and harvested at S1 and S2 were appraised for fresh and dry yield traits. They were further analyzed for macro- and micromineral content using inductively coupled plasma optical emission spectrometry (ICP-OES), carotenoid content using high-performance liquid chromatography with a diode-array detector (HPLC-DAD), volatile organic compounds using solid-phase microextraction followed by gas chromatography-mass spectrometry (SPME-GC/MS), anthocyanins and polyphenols using liquid chromatography-high resolution-tandem mass spectrometry (LC-MS/MS) with Orbitrap technology and for chlorophyll and ascorbate concentrations, well as antioxidant capacity by spectrophotometry. Analysis of compositional profiles revealed genotype as the principal source of variation for all constituents. The response of mineral and phytochemical composition and of antioxidant capacity to the growth stage was limited and largely genotype-dependent. It is, therefore, questionable whether delaying harvest from S1 to S2 would significantly improve the bioactive value of microgreens while the cost-benefit analysis for this decision must be genotype-specific. Finally, the lower-yielding genotypes (Mizuna and Pak Choi) registered higher relative increase in fresh yield between S1 and S2, compared to the faster-growing and higher-yielding genotypes. Although the optimal harvest stage for specific genotypes must be determined considering the increase in yield against reduction in crop turnover, harvesting at S2 seems advisable for the lower-yielding genotypes.

Heat- and Ultrasound-Assisted Aqueous Extraction of Soluble Carbohydrates and Phenolics from Carob Kibbles of Variable Size and Source Material.

Aqueous extraction of carob kibbles is the fundamental step in the production of carob juice and carob molasses. Improving the theoretical yield in sugars during organic solvent-free aqueous extraction is of prime interest to the food industry. Collateral extraction of phenolics, however, must be monitored as it influences the sensory and functional profile of carob juice. We presently examined the impact of source material, kibble size, temperature, and duration on the efficiency of extracting sugars and phenolics aqueously by conventional heat-assisted (HAE) and ultrasound-assisted (UAE) methods. Source material was the most influential factor determining the concentration of phenolics extracted by either method. Source material also influenced the relative proportions of sucrose, glucose, and fructose, which may impact the perceived sweetness of the juice. Kibble size (medium size M = 9-13 mm; powder size P = 1-4 mm) was more influential with UAE than HAE for both sugars and phenolics but was rendered less influential with prolonged UAE duration. Increasing HAE temperature (from 25 °C to 75 °C) favored the extraction of phenolics over sugars; however, prolonging extraction at 25 °C improved sugar yield without excessive yield in phenolics. Disproportionate extraction of phenolics over sugars limits the use of heat-assisted extraction to improve sugar yield in carob juice production and may shift the product's sensory profile toward astringency. Prolonged extraction at near ambient temperature can, however, improve sugar yield, keeping collateral extraction of phenolics low. Ultrasound agitation constitutes an effective means of extracting sugars from powder-size kibbles. Industrial application of both methodologies depends on the targeted functional and sensory properties of carob juice.