Increase In Polyphenol Content Research Articles

Effect of roselle and purple rice powder on baking quality and aroma characteristic of bread

The effects of different dosages of roselle flour (0 %, 4 %, and 8 %) and purple rice flour (5 %, 10 %, and 15 %) on the properties of the dough, the quality of the bread, the phenolic compounds contained, the anthocyanin content and the aroma profile were investigated by adding roselle flour and purple rice flour to the wheat flour. The results showed that the addition of purple rice flour elevated the G′ and G″ of the dough and improved the viscoelasticity of the bread. The addition of roselle flour disrupted the gluten network structure in the bread, resulting in an increase in chewiness and hardness, but within acceptable limits. The color of the bread also changed significantly. In addition, increased polyphenol content in the bread, roselle flour, and purple rice flour significantly (p < 0.05) increased the aroma profile of bread, giving it a richer odor. In particular, the presence of more acids, alkanes and heterocyclic compounds associated with fruity flavors also adds a distinctive burnt and ‘roasted’ note. Therefore, the addition of moderate amounts of roselle flour and purple rice flour was beneficial in improving the baking quality of bread, especially positively affecting the flavor.

Encapsulation of Olive (Olea europaea L.) Pruning Waste Particles by Supercritical CO2 Technology.

Olive leaves (Olea europaea L.) contain a multitude of bioactive compounds such as sterols, carotenes, triterpenic alcohols and phenolic compounds. These compounds have been shown to exhibit antiviral, antioxidant, candida-growth-inhibitory, anticancer, antifungal, anti-inflammatory and antibacterial activities. In this sense, submicron particles from olive leaves with antioxidant activity were precipitated by supercritical antisolvent extraction in a previous work. Moreover, encapsulation enables the delayed release of compounds and avoids the first-step effect in medical therapies. Therefore, this work focused on encapsulation of particles with a certain antioxidant capacity from olive pruning waste using supercritical technology. A variety of experiments were carried out to test how the different operating variables (pressure, temperature and extract-polymer ratio) affect. Morphology was analyzed by SEM microscopy, obtaining encapsulates between 1 and 5 microns in size. The antioxidant capacity was determined by the DPPH assay, with most of the encapsulates having AAI values between 0.5 and 1 (moderate antioxidant capacity). An increase in polyphenol content was observed in the 1:3 ratio tests. The release of the compounds in gastric simulated medium was retarded by the polymeric encapsulation, while in intestinal fluid, the solubility was improved compared to the unencapsulated particles. Overall, the supercritical encapsulation process for the natural extract of olive pruning residues has proven to be effective in obtaining antioxidant particles with different release profiles.

Enhanced bio-extraction of medicinally important plants using xylano-pectinolytic enzymes produced concurrently by Bacillus pumilus AJK

Medicinal plant extracts obtained by chemical methods have drawbacks such as high chemical, time and energy consumption, byproduct formation, lower quality and efficiency, high toxicity and lead to degradation of thermo-sensitive bioactive compounds. The purpose of this study was to investigate the ability of crude xylano-pectinolytic enzymes concoction in bio-extraction of medicinally important plant extracts, in order to reduce the use of chemical solvents for extraction. In this regard, various conditions including material to liquid ratio (MLR), enzyme dose, treatment time and stirring speed were optimized and several physico-chemical parameters including pH, total soluble solid (TSS), total dissolved solid (TDS), clarity, reducing sugar, polyphenolic content, viscosity and filterability were studied. The bio-extraction efficiency was found to be best at material-to-liquid ratio (MLR) 1:5-1:6 (g/mL), enzyme dose range between 15:60 to 20:80 (IU/g), treatment time range between 180- 240 min and stirring speed range between 50-60 rpm. Enzymatic extraction of medicinal plants resulted in 7-17% increase in clarity, 27-50% increase in TSS, 3-42% increase in reducing sugars, 20-42% increase in polyphenolic content, 13-53% increase in TDS, 15-22% increase in filterability along with decrease of 3-5% in pH and 18-43% in viscosity. Hence, this eco-friendly bio-extraction strategy could reduce the chemical usage, along with improvement of the physico-chemical properties of medicinally important extracts. The technique also enables the application of greener chemistry in the pharmaceuticals to optimize cleaner methods of extraction. This is the first report manifesting bio-extraction of medicinally important plant extracts using crude xylano-pectinolytic enzymatic concoction produced by a single bacterial isolate.

Utilization of Spent Coffee Grounds as a Feed Additive for Enhancing the Nutritional Value of Tenebrio molitor Larvae

Increasing demand for sustainable protein sources has spurred interest in the exploration of alternative protein sources with a reduced environmental impact. This study investigates the use of spent coffee grounds (SCG), a widely available by-product, as a feed additive for Tenebrio molitor larvae, aiming to contribute to the circular economy and enhance the nutritional quality of the insects. The larvae were fed with a mixture of bran (the conventional feed) and SCGs (10 and 25% w/w). Larval viability, growth, and nutritional composition, including protein, fat, carbohydrates, ash, carotenoids, vitamins A and C, and polyphenols, were evaluated. Increasing the proportion of SCGs in the larvae’s feed led to an enhanced nutritional value of the larvae. In particular, crude protein increased by 45.26%, vitamin C showed an increase of 81.28%, and vitamin A showed an increase of 822.79%, while polyphenol content increased by 29.01%. In addition, the oil extracted from these larvae showed enhanced nutritional value and greater resistance to oxidation. The results highlight the promising use of SCGs as a feed additive for T. molitor larvae, offering a sustainable approach to enhance their nutritional value. Delving deeper into the results, the addition of 10% SCGs resulted in a 45.26% increase in crude protein compared to the SCG0 sample. Concurrently, increasing SCGs in the dietary substrate led to an increase in vitamin content; in sample SCG25, vitamin C content increased by 81.28% while vitamin A content increased by 822.79% compared to the control sample. Moreover, there was a large increase in polyphenol content with the SCG25 sample showing the highest value, which was a 29.01% increase over the control sample.

Heat shock increases the anti-inflammatory and anti-obesity activity of soybean by increasing polyphenol, antioxidant and aglycon form isoflavones

We know that heat shock can activate the functional components in soybeans, but we don't know the type, level, and duration of heat shock for maximum activation. To address this, the present study investigated the changes in functional components like polyphenols, antioxidants, and isoflavones in soybeans at various temperature levels and durations with their respective functionality or health benefits. For this, treated seed samples were extracted with 70 % ethanol. Heat shock at 60 °C for 2 h increased polyphenol content (60.67 % of control) and antioxidant activity for both ABTS (41.14 % of control) and DPPH (217.72 % of control). This also increased the beneficial aglycone form of isoflavones that includes daidzein (8.36-fold of control), glycitein (3.85-fold of control) and genistein (20.50-fold of control) but decreased the harmful β-glucoside form (3.65-fold) including daiazin (1.84-fold of control); glycitin (1.45-fold of control) and genistin (23.88-fold of control) over untreated dry seed. This may happen because of the conversion of conjugated β-glucoside isoflavones to their aglycone forms that have various health benefits. Maximum inhibition of NO production in RAW 264.7 cells was achieved by samples elicited for 2 h with 300 μg/mL concentration. This sample also confirmed the maximum anti-obesity activity treated against 3-T-3L1 cells. This study summarized that heat shock at 60 °C for 2 h increased polyphenols, antioxidants, and aglycon isoflavone in soybeans resulting in increased anti-inflammatory and anti-obesity activity.

Modulation of VOC fingerprint and alteration of physiological responses after supplemental LED light in green- and red-leafed sweet basil (Ocimum basilicum L.)

Narrowband green (G), blue (B), red (R), and polychromatic (W ‒ R:G:B, 1:1:1) lights were supplemented (250 µmol photon m‒2 s‒1; 5 h d−1; 21 d) to ambient light with Light Emitting Diodes (LED) in green- (‘Tigullio’; TI) and red-leafed (‘Red Rubin’; RR) sweet basil (Ocimum basilicum L.) plants. The aim of this work was to evaluate LED-triggered variations in biometric and morpho-anatomical traits, photosynthesis and secondary metabolite production to ‘photomodulate’ plant performance via monochromatic LED light supplementation.In both the cultivars, light supplementation did not alter plant biomass production compared to controls and at the amplitude applied therein any LED supplementation resulted in oxidative stress, as evidenced by slight changes in chlorophyll fluorescence parameters and H2O2 staining in leaves. Conversely, monochromatic LEDs selectively modulate metabolomics profile in both green- and red-leafed basil; e.g., B lights increased polyphenol content in TI, whilst G light resulted effective in reducing cyanidin-3-coumaroil-glucoside one of the prevalent acylated anthocyanin of RR. Volatilome profile unveiled profound waveband-dependent alterations though consistently eugenol, characterised by a clove flavor, and also considered one of the major toxic compounds in sweet basil, decreased with all the LED treatments, making green-leafed basil a more pleasant and safer product.Our dataset offers the clear evidence that monochromatic LED light supplementation represents a valid tool to modulate the accumulation of targeted secondary metabolites in planta.

Conditioning of Scots pine (Pinus sylvestris L.) sowing material

ABSTRACT Scots pine is the main forest forming species in Poland. Despite the great importance of natural reconditioning of forest trees, a substantial source of reforestation is the nursery production of seedling material. Pre-sowing seed conditioning, consisting of chemical and physical treatments, is commonly used to improve seed quality as well as to advance uniform development and increase plant efficiency. The influence of semiconductor laser irradiation wavelength on Scots pine seeds (Pinus sylvestris L.) was tested in both laboratory and pot experiments. Irradiation rates used in trials were (D3) three-, (D6) six- and (D9) nine-fold of the basic rate of 2.5·10−1 J·cm−2 with a control (D0) of non-irradiated seeds. Irradiation accelerated emergence and increased seedling numbers. The germination energy and capacity of tested Scots pine genotypes were reduced under higher (D6) doses of laser irradiation. Stimulation of morphological traits and increase in chlorophyll contents was observed under the lowest (D3) irradiation rate, while an increase in polyphenol contents occurred under the highest, nine-fold rate of irradiation.

Induction of Biosynthesis Antioxidant Molecules in Young Barley Plants by Trioxygen.

Young barley plants are a good source of bioactive compounds. This paper presents the effects of gaseous O3 (trioxygen or ozone) on the biosynthesis of compounds, determining the antioxidant potential of young barley plants. The total content of polyphenols was determined along with their profile, as well as total antioxidant potential and vitamin C content. The highest contents of these compounds were identified in young barley plants exposed to gaseous O3. The main bioactive compound, representing polyphenols, determined in the examined raw materials was saponarin (isovitexin 7-O-glucoside). The induction of increased biosynthesis of these molecules was directly linked to the modification of the activity of selected enzymes. The increased polyphenol content resulted from the modified activities of polyphenol oxidase (PPO) and phenylalanine ammonia lyase (PAL). On the other hand, the oxidative effect of ozone on barley plants was reduced, owing to the modified activities of catalases (CAT), glutathione peroxidases (SOD) and guaiacol peroxidase (GPOX). Analysis of the results showed that by applying gaseous O3 at a dose of 50 ppm for 10 min, the contents of bioactive compounds can be maximised in a residue-free way by activating oxidative stress defence mechanisms.

Influence of Green Tea Added to Cherry Wine on Phenolic Content, Antioxidant Activity and Alpha-Glucosidase Inhibition during an In Vitro Gastrointestinal Digestion

Cherries are a good source of bioactive compounds, with high antioxidant activity as well as nutritional and therapeutic importance. In this study, cherry wines enriched with green tea infusion (mild and concentrated) were produced, and their biological properties were evaluated. During winemaking, the main vinification parameters (alcohol, reducing sugars, acidity, total polyphenol content) as well biological activity (antioxidant activity, alpha-glucosidase inhibition potential) were determined. An in vitro digestion process was also performed to evaluate the impact of the gastrointestinal environment on the biological stability of the wines, and to analyze the interactions of wine-intestinal microflora. The addition of green tea to the cherry wine significantly increased the total polyphenol content (up to 2.73 g GAE/L) and antioxidant activity (up to 22.07 mM TE/L), compared with the control wine. However, after in vitro digestion, a reduction in total polyphenols (53–64%) and antioxidant activity (38–45%) were noted. Wines fortified with green tea expressed a stronger inhibition effect on intestinal microflora growth, of which E. coli were the most sensitive microorganisms. The tea-derived bioactive compounds significantly increased the potential of alpha-glucosidase inhibition. The proposed wines could be a good alternative type of wine, with an increased polyphenol content and the potential to control the insulin response supporting therapy for diabetes.

The effects of conjugation of walnut protein isolate with polyphenols on protein solubility, antioxidant activity, and emulsifying properties

Alkaline-extracted walnut protein isolate (AWPI) shows poor solubility in aqueous solutions, resulting in relatively low emulsion capacity. This work investigated the influence of ellagic acid (EA) or epigallocatechin-3-gallate (EGCG) conjugation on the solubility and emulsifying properties of AWPI. The increase in polyphenol content and decrease in free amino and thiol groups of walnut proteins confirmed successful conjugation. AWPI polyphenol conjugates showed significantly reduced surface hydrophobicity, greatly enhanced surface charge, and consequently improved solubility. Circular dichroism (CD) results indicated that the polyphenol-conjugated AWPI contained relatively higher α-helical and lower β-sheet contents than AWPI. The antioxidant capacity of the polyphenol-conjugated AWPI was significantly enhanced. Additionally, polyphenol conjugation resulted in decreased mean particle sizes and increased surface charges of the walnut protein-covered oil droplets. The emulsions stabilized by AWPI-polyphenol conjugates were relatively more stable over a range of pH values (7.0–11.0) and thermal treatments (25 °C–90 °C). Moreover, they exhibited greater storage stability than those stabilized by unmodified AWPI.

Effect of Thermal Processing on the Metabolic Components of Black Beans on Ultra-High-Performance Liquid Chromatography Coupled with High-Field Quadrupole-Orbitrap High-Resolution Mass Spectrometry.

An ultra-high-performance liquid chromatography coupled with high-field quadrupole-orbitrap mass spectrometry (UHPLC-QE-MS) histological platform was used to analyze the effects of two thermal processing methods (cooking and steaming) on the nutritional metabolic components of black beans. Black beans had the most amino acids, followed by lipids and polyphenols, and more sugars. Multivariate statistical analysis indicated that heat processing significantly affected the metabolic component content in black beans, with effects varying among different components. Polyphenols, especially flavonoids and isoflavones, were highly susceptible. A total of 197 and 210 differential metabolites were identified in both raw black beans and cooked and steamed black beans, respectively. Cooking reduced the cumulative content of amino acids, lipids, polyphenols, sugars, and nucleosides, whereas steaming reduced amino acid and lipid content, slightly increased polyphenol content, and significantly increased sugar and nucleoside content. Our results indicated that metabolic components were better retained during steaming than cooking. Heat treatment had the greatest impact on amino acids, followed by polyphenols, fatty acids, sugars, and vitamins, indicating that cooking promotes the transformation of most substances and the synthesis of a few. The results of this study provide a basis for further research and development of nutritional products using black beans.

Tea Infusions as a Source of Phenolic Compounds in the Human Diet

Phenolic compounds are components with proven beneficial effects on the human body, primarily due to their antioxidant activity. In view of the high consumption of tea and the numerous factors that affect the nutritional value of its infusions, the aim of this study was to identify the effects of tea type and duration of leaf extraction with water on the levels of phenolic compounds and other components that determine biological activity (oxalates, Ca, Na, Cu, and Mn). Based on assays, infusions of red tea prepared for 20 min were found to be the best source of phenolics (202.9 mg/100 mL), whereas the lowest level of these compounds was determined in infusions of black tea extracted from leaves for 30 min (46.9 mg/100 mL). The highest degree of increase in polyphenol content (by approx. 50%) was noted in red and green tea infused for between 10 and 20 min, whereas for black tea, polyphenol levels decreased with time. The biological activity of tea infusions appears to be determined to the greatest extent by the interactions between phenolic compounds and oxalates (r = 0.6209), calcium (r = 0.8516), and sodium (0.8045). A daily intake of three to four mugs (1 L) of tea infusions provides the human body the entire amount of phenolics recommended for health reasons (as regards red tea, this is possible at 1/3 of the volume) and covers the daily requirement for manganese, as well as (partially) copper.

Efficacy of the Kombucha Beverage Derived from Green, Black, and Pu’er Teas on Chemical Profile and Antioxidant Activity

Kombucha is a symbiotic culture of bacteria and yeast which produces a high-end fruity fitness beverage by fermentation of normal tea for approximately two weeks. In addition to the advantage of being a low-sugar probiotic-rich drink, kombucha also offers the benefits of the tea used for its preparation, especially its high antioxidant content. In this research, kombucha tea was prepared by using three different tea types: green, black, and pu’er tea, and the chemical profiles and antioxidant activity were analyzed during the fermentation process (up to 20 days). The results showed that the tea type has an obvious influence on the factors associated with the antioxidant potential. The fermentation process caused a marked increase in polyphenol content and antioxidant activity initially, but this slowed progressively over time. In contrast, the fermentation of black tea contributed to the degradation of flavonoids but showed no significant effect on the other tea types. Therefore, we conclude that the tea type selected to make kombucha affects the end product as well as the fermentation time.

Impact of germination on phenolic composition, antioxidant properties, antinutritional factors, mineral content and Maillard reaction products of malted quinoa flour

The study aimed at improving and comparing the nutritional profile of black (BQ) and white quinoa (WQ) through malting at different germination periods (24, 48, 72 and 96 h), followed by drying at 50 °C, decluming, grinding and sieving to obtain malt flour. The changes in protein, reducing sugar, Maillard reaction products (MRPs), minerals, free and bound polyphenols and antioxidant activity were noted. Malting caused significant increase in polyphenolic content, antioxidant capacity and fluorescence of advanced MRP (FAST) index. The highest increment was noted in malts germinated for 48 and 72 h. BQ malts were marked by higher bound hydroxycinnamic acids, flavan-3-ols, magnesium, potassium and antioxidant activity, while, WQ malts had lower saponin, phytic acid but higher protein, iron, calcium, FAST index. WQ exhibited highest increment (27.23%) in antioxidant activity even though it had lower polyphenols than BQ after malting. Major loss in polyphenols and proteins occurred in malt germinated for 96 h.

THERMAL, MECHANICAL AND WATER SORPTION PROPERTIES OF XANTHAN-BASED COMPOSITE CRYOGELS

The thermal, mechanical, rheological, and surface characteristics of some xanthan/poly(vinyl alcohol)/red grape pomace composite cryogels prepared by the freeze/thawing approach were investigated. The results were discussed in comparison with those obtained for individual xanthan or poly(vinyl alcohol) cryogel networks synthesized under the same conditions. The mechanical strength of the cryogels was enhanced by increasing the number of freeze/thawing cycles, and by the addition of a natural polyphenol (i.e. red grape pomace). The thermal stability of the poly(vinyl alcohol) in the blend significantly decreased upon the addition of 50% xanthan, while the presence of a single neat melting profile indicated good component miscibility for the chosen ratios. The water sorption capacity depended on the amount of polyphenol incorporated, thus the hydrophilicity of the cryogel films decreased with the increase of polyphenol content.

The impact of high-pressure processing on the polyphenol profile and anti-glycaemic, anti-hypertensive and anti-cholinergic activities of extracts obtained from kiwiberry (Actinidia arguta) fruits

This study analysed the impact of high pressure processing (HHP) on the inhibitory effects (IC50) of kiwiberries (cv. 'Weiki'), on the formation of advanced glycation end-products (AGEs) and the activity of angiotenisn-converting enzyme (ACE) and the enzyme acetylcholinesterase (AChE). The polyphenol profile (HPLC-MS/MS) and antioxidant capacity (PCLACW, ABTS, FRAP) were also studied. HHP-treated 'Weiki' (450 MPa/5 min and 650 MPa/5 min) was the most potent inhibitor of AGEs in the BSA-GLU model (6.52 mg/mL on average) relative to other materials (12.09–7.21 mg/mL). Among all samples assayed in the BSA-MGO model (61.97–14.48 mg/mL), HHP-treated 'Weiki' (450 MPa/5 min) showed the highest anti-AGE activity (12.37 mg/mL). Pressurization (450 MPa/5 min) significantly enhanced the anti-ACE (14.09 mg/mL) and anti-AChE (16.95 mg/mL) potentials of the tested extract relative to the other materials (23.75–14.50 mg/mL and 37.88-19.69 mg/mL, respectively). Pressurization increased polyphenol content and antioxidant capacity of the samples analysed.

Use of olive (Olea europaea L.) leaves as beer ingredient, and their influence on beer chemical composition and antioxidant activity.

Olive leaves are well known for their high polyphenol content and beneficial effects to human health. The two main phenolic compounds of olive leaves are oleuropein and 3-hydroxytyrosol. Use of olive leaves as beer ingredient was evaluated, to investigate their contribution to bitterness and antioxidant activity of beer. Thirteen beer samples were produced, adding olive leaves during boiling at different boiling times, in different forms and concentrations. Three different forms were used: dry crumbled leaves, infusion, and atomized extract. The effects of olive leaves addition were evaluated through following analysis: total polyphenols content, oleuropein and 3-hydroxytyrosol content, antioxidant capacity, sensory analysis, shelf-life prediction. Results confirmed that addition of olive leaves highly increased polyphenol content of beers. Boiling time favored hydrolysis of oleuropein to 3-hydroxytyrosol. Antioxidant activity was not influenced by addition of olive leaves. Higher polyphenol content of beer samples increased colloidal instability of beer. Sensory analysis results demonstrated that about 10g/L of olive leaves imparts a sour/astringent taste and herbal aroma. A lower quantity of olive leaves (about 5g/L) allowed to obtain a beer with a pleasant sensory profile. PRACTICAL APPLICATION: Our research was inspired by both the high interest in alternative ingredients able to add nutraceutical value to traditional food, and by the growing craft beer market, with its constant research for innovative and characterizing ingredients. This project has several aims: evaluate if olive leaves could partially substitute hops in beer bittering (reducing costs); if their addition increase beer polyphenol content; which amount and using technique gives the best results in terms of polyphenol extraction and sensory profile; how this addition influence beer stability. This work could then encourage new research about the nutraceutical value of this new type of beer.

Effect of processing conditions on bioactive compounds and glycemic index of the selected landrace rice variety in pre-diabetes

Paddy processing can affect glycemic index (GI) and bioactive compounds of rice. Therefore, the effects of processing conditions such as germination, parboiling and polishing on total polyphenols, ferulic acid and gamma-aminobutyric acid (GABA) contents of seven landrace varieties from Thailand were investigated. Subsequently, the best rice variety was chosen to evaluate GI in pre-diabetic subjects. Four different rice forms used were brown rice (BR), parboiled brown rice (PBR), germinated parboiled brown rice (GPBR) and polished rice (PR). Results showed that polishing process strongly reduced all bioactive compounds. In contrast, parboiling the grains slightly increased polyphenol, and germination followed by parboiling significantly increased polyphenol content. Ferulic acid content was found to be similar among BR, PBR and GPBR and the highest GABA content was found in GPBR. Furthermore, Leuang Awn variety exhibited the highest polyphenol (126.70 ± 1.08 mg GAE/100 g), ferulic acid (17.77 ± 0.16 mg/100 g) and GABA content (78.57 ± 1.00 mg/100 g) and was selected for GI study. PBR and GPBR had medium GI values (55.10 ± 5.37 and 60.58 ± 6.48) and PR showed high GI value (83.10 ± 5.10). In conclusion, parboiling and germination had less effects on the bioactive compounds of whole grain rice and produced low-medium GI, which could be beneficial for health promotion.

Polyphenols Content of Indonesian Tea Clones on Optimum Manuring Condition

Tea (Camellia sinensis (L.) Kuntze) has been known as a functional drink containing bioactive polyphenols with health benefits effect. Polyphenols in tea are not only influenced by climate but also by clone types and cultivation techniques. Recently, technological developments in tea commodities are not only focused on the quantity of production but also the content of polyphenols. Previous studies reported that the application of Nitrogen (N), Phosphorus (P), and Potassium (K) fertilizers played a role in increasing the polyphenol content in tea. Research Institute for Tea and Cinchona (RITC) has released GMB Series clones that have high productivity compared to other clones. The objectives of this study were to determine the content of tea polyphenols of various GMB series clones on optimum manuring conditions. This research was carried out in 2018 in the high elevation areas (1,350 m masl) and medium elevation (800 m masl). At the high elevation area at RITC Gambung Experimental Plantation, showed that on optimum manuring condition had an effect on the increase in polyphenol content in most GMB clones (14.83 - 15.43% dw) compared to control (10.56% dw) and GMB 1, GMB 4, GMB 7 and 9 clines showed significantly different effect on the content of total polyphenols. Tests which conducted on the medium elevation area at Cianjur, West Java, showed that under optimum manuring condition, the range of total above 15% with the highest polyphenols were obtained in GMB 1 clone at the dosage application of NPKMg (300:30:249:50) kg ha−1year−1

Effects of a Permanent Soil Cover on Water Dynamics and Wine Characteristics in a Steep Vineyard in the Central Spain

The study of alternative soil managements to tillage, based on the evidence of climate change in the Mediterranean basin, is of great importance. Summer and autumn are critical seasons for soil degradation due to the high-intensity, short-duration storms. Vineyards are vulnerable, especially on steep slopes. The particular effects of storms over the years under different soil conditions due to different management practices are not frequently addressed in the literature. The aim of this study was to examine the differences between runoff and soil moisture patterns influenced by 2 treatments: traditional tillage (Till) and a permanent cover crop. A shallow-rooted grass species Brachypodium distachyon (L.) P. Beauv. with considerable density coverage was selected as cover crop. This annual species was seeded once in the first year and then allowed to self-seed the following years. Tillage was performed at least twice in spring to a 10- to 15-cm depth and once in late autumn at a depth of 20 to 35 cm. Rainfall simulation experiments were performed, 1 year after treatments, using high-intensity rainfall on closed plots of 2 m2, located in the middle strips of the vineyard with different treatments. The effects of simulated rainfall experiments were determined in 3 different moments of the growth cycle of cultivar: (1) in summer with dry soils, (2) in early autumn with moderate soil moisture, and (3) in autumn with wet soils. During the 2-year trial, the soil moisture level in the soil upper layer (0-10 cm) was higher for Till treatment (14.1% ± 2.4%) compared with that for cover crop treatment (12.3% ± 2.0%). However, soil moisture values were more similar between treatments at 35 cm depth (12% ± 1%), with the exception of spring and autumn; in spring, water consumption in the cover crop treatment was the highest, and the moisture level at 35 cm depth was reduced (12%) compared with that for Till treatment (13%). In autumn, in cover crop treatment, higher water infiltration rate in soils led to higher soil moisture content at 35 cm (11%) compared with that of Till treatment (10%). The effects of simulated rainfall experiments on runoff and infiltration under different soil conditions and management practices vary seasonally. Runoff was significantly higher in summer for cover crop treatment (11%) as compared with that for Till management (1%), but significantly lower (3%) with wetter soils than for Till treatment (22%) in autumn. Thus, the simulation experiments with wet soils using cover crops produced higher infiltration rates and, consequently, the higher soil moisture content in the following days. The difference between seasons is attributed to the greater porosity of soil under Till treatment in summer, which resulted from the shallow plowing (10-15 cm depth), carried out to reduce moisture competition between weeds. The effect of traditional spring plowing was short-lived. The infiltration of water increased by cover crop treatment as compared with tillage in autumn both before and after ripping. Management practices did not influence wine parameters, as no significant differences were found between wine organoleptic characteristics in the duo-trio wine tastings, similarly, no differences were found for alcoholic degree, acidity, reduced sugars, and pH; however, a trend for a positive increase in polyphenol contents was noticed. Therefore, properly managed to avoid water shortages, cover crops can be recommended for soil protection in semi-arid environments.