Untreated Grapes Research Articles

Can the use of particle films for fruit protection against medfly alter the behavior of the parasitoid Diachasmimorpha longicaudata?

AbstractThe use of particle films, especially kaolin‐based films, is a promising technology to control infestations of Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), an important pest of fruits. However, its effects on one of the most important biocontrol agents of this fly in Brazil, the parasitoid Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae), are unknown. This study aimed to evaluate the influence of mineral particle films on the oviposition behavior of D. longicaudata and to determine the success of parasitism in C. capitata using grape (Vitis vinifera L., Vitaceae) as substrate. Before the bioassays, the color characteristics, firmness, total soluble solid content, pH, and titratable acidity of the fruits were determined. Grapes were immersed in suspensions of kaolin Surround WP, kaolin 607, kaolin 608, and distilled water (control); thereafter, they were perforated, and two C. capitata third instars were inserted into the orifice. The grapes were then exposed to a female parasitoid. The frequency and duration of the following behavioral parameters of D. longicaudata were evaluated: landing on fruit, inspection, buccal contact, oviposition, cleaning, resting on fruit, and resting on cage. Furthermore, parasitism success was assessed. Mineral particle films altered the color and firmness of the grapes. The females of D. longicaudata performed all distinguished behaviors in treated and untreated grapes, except buccal contact, which was not done on the kaolin‐treated fruits. Kaolin 607 negatively affected landing, inspection, puncture, and rest behaviors; kaolin Surround WP only reduced inspection and puncture. Fruit coating with all three tested kaolin products decreased the success of parasitism of D. longicaudata, indicating that particle films applied to plant organs can affect the behavior of this natural enemy.

Foliar application of putrescine, salicylic acid, and ascorbic acid mitigates frost stress damage in Vitis vinifera cv. ‘Giziluzum’

BackgroundCold stress is an effective factor in reducing production and injuring fruit trees. Various materials, such as salicylic acid, ascorbic acid, and putrescine, are used to alleviate the damage of abiotic stress.ResultsThe effect of different treatments of putrescine, salicylic acid, and ascorbic acid on alleviating the damage of frost stress (− 3 °C) to grapes ‘Giziluzum’ was investigated. Frost stress increased the amount of H2O2, MDA, proline, and MSI. On the other hand, it decreased the concentration of chlorophyll and carotenoids in the leaves. Putrescine, salicylic acid and ascorbic acid significantly increased the activities of catalase, guaiacol peroxidase, ascorbate peroxidase, and superoxide dismutase under frost stress. Following frost stress, the grapes treated with putrescine, salicylic acid, and ascorbic acid showed higher levels of DHA, AsA, and AsA/DHA than the untreated grapes. Our results showed that the treatment with ascorbic acid outperformed the other treatments in adjusting frost stress damages.ConclusionThe use of compounds, such as ascorbic ac id, salicylic acid, and putrescine, modulates the effects of frost stress, thereby increasing the antioxidant defense system of cells, reducing its damage, and stabilizing stable cell conditions, so it can be used to reduce frost damage to different grape cultivars.

Development of zinc oxide nanoparticles as safe coating for the shelf life extension of grapes (Vitisvinifera L., Red Globe) fruits

The effects of zinc oxide nanoparticles coating (NZO) developed from chitosan (CH) with incorporation of bergamot essential oil (BO) were investigated to extend the shelf life of grapes (Vitisvinifera L., Red Globe). Treated and untreated grapes were determined for some postharvest and phytochemical properties such as decay incidence, firmness, polyphenol oxidase enzyme activity (PPO), proximate analysis, and sensory evaluations. Besides, that microbial growth against S. typhimurium bacteria was also evaluated during 16 days of storage period of grapes at 25 °C. Descriptions of coating treatments were the following; control “COL” (distilled water/glycerol (1%)/acetic acid (0.5%)); chitosan “CH” with priority 85% (1%), distilled water/glycerol (1%)/acetic acid (0.5%); chitosan/nano zinc oxide (1%), partial size of (15 nm) “CH-NZO;” chitosan/nano zinc oxide/bergamot oil (1%) “CH-NZO-BO.” The control treated berries started to rot after 7 days; the noted highest corruption on 16th day s of storage (32.51). While CH berries coated became rotten after 9 days, those coated with CH–NZO and CH–NZO–BO achieved the lowest decay incidence percentage with no remarkable differences after 16 days (10.11% and 9.13%), respectively. The loss of firmness value was more seriously considered for the COL berries 3.84 N after the 16th day. On the other hand, the highest firmness value was for CH–NZO–BO which recorded 8.27 N. In the same trend, CH and CH–NZO achieved similar values after 16 days (6.31 N and 6.98 N), respectively. The lowest PPO activity was observed for COL berries at 0.31 Unit/Minute after 16 days of storage. Though, the highest activity was recorded by CH–NZO–BO treatment at 0.99 Unit/Minute. The content of proteins was between 2.32 and 3.04%, fats between 0.30 and 0.43%, and total carbohydrates between 78.47 and 78.65% on the 16th day of storage. The highest reduction in the numbers of microbial growth 2.78 Log CFU/Berry occurred by coating with CH–NZO–BO at the end of the storage period, while no inhibition was detected with COL and CH treatments which recorded 4.99 and 4.69 Log CFU/Berry, respectively. The visual aspect in COL samples showed a serious reduction of 1.10 with high rates of dehydration and browning, while CH-NZO–BO samples showed the highest rate of 4.33. CH–NZO–BO samples also showed a relatively high rate of firmness of 4.11, crunchiness of 3.92, and sourness of 3.53. CH–NZO recorded the highest rates for juiciness 4.15 and sweetness 3.51. Though, the CH–NZO–BO coating can be recommended for food industry.

Seedlessness detection in ‘White Malaga’ table grapes using near-infrared spectroscopy

‘White Malaga’ table grapes are seeded and widely grown in Thailand. They are converted by induction into seedless grapes to increase their value. It is difficult to identify seedlessness in table grapes without destroying the grape berry. The present work thus described a quick and non-destructive method for detecting and predicting seedlessness in ‘White Malaga’ table grapes by using near-infrared (NIR) spectroscopy together with chemometric analysis. The NIR spectra of 280 grape samples were recorded after harvest. Firmness, total soluble solids (TSS), pH, titratable acidity (TA), tartaric acid, number of seeds, and relevant physical properties were analysed. The width and weight of plant growth regulator (PGR) treatments were significantly lower than those in the untreated grapes, while the length, firmness, TA, and tartaric acid were not significantly different. Partial least square (PLS) regression was used to investigate the prediction. Classification models, namely principal component analysis (PCA) and quadratic discriminant analysis (QDA), were used to identify seedlessness. It was found that, QDA, as a representative of linear classification, resulted in the best classification of seeded and seedless performance, where the percentages of predictive ability (%PA), the percentages of model stability (%MS), and the percentages of correctly classified (%CC) were 97.27, 98.57, and 96.23%, respectively, for the training set with no pre-processing. Therefore, the NIR spectroscopy technique can be a non-destructive technique for seedlessness detection in ‘White Malaga’ table grapes.

Effect of Adding Pomegranate Peel Extracts on the Stability of Grape Seeds Oil During Storage

The effect of adding pomegranate peel extract to Grape seed oil and studying the effect of addition on the stability of oil during storage period and comparing the results with a sample of grape seed oil during the storage period fortified with the same percentage of BHA. It was found that the addition process improved the physicochemical properties of oil, as it was noted that the value of peroxide number of oil which treated with pomegranate extract amounted to 34.07 μg / g, while the value of the same characteristic for the oil treated with BHA was 28.02 μg / g It was found from study of the rest of traits that their value was less than that of the untreated grape seed oil, and it was found that the absorption of light was less in the treated oil than in the untreated oil. total phenols. And the rest of the characteristics, but it is not having ability of BHA, which works to maintain levels of physicochemical properties within acceptable limits almost.

A holistic approach to using biostimulants on the red grapevine variety, Mouhtaro - from grape to wine

One of the main effects of applying biostimulants to grapevines is an increase in berry phenolic compound content. In the current study, grapes treated at veraison with abscisic acid (ABA), benzothiadiazole (BTH) and chitosan (CHT) were vinified. Treated grapes, compared to untreated grapes (the control), resulted in wines with a significantly higher concentration of anthocyanins and phenolic content. Furthermore, in a descriptive sensory analysis, wines made from treated grapes were found to have significantly more intense fruity notes and aroma and better overall mouthfeel quality.

Effects of Dietary Incorporation of Grape Stalks Untreated and Fungi-Treated in Growing Rabbits: A Preliminary Study.

Simple SummaryThe use of winery by-products as an animal feed ingredient in rabbit production can enhance the sustainability of this livestock sector by reducing feeding costs and simultaneously diminishing environmental problems related to the management of those by-products. White-rot fungi have been studied for the delignification of lignocellulosic materials due to their potential to decrease the content of lignin. In fact, white-rot fungi also improve the nutritional value due to the deposition of bioactive compounds, acting as a possible biological treatment to enhance the nutritive value of grape stalks. The objective of this work was to evaluate the incorporation of untreated grape stalks and fungi-treated grape stalks in rabbits’ diets.This study aimed to evaluate the effect of the incorporation of untreated grape stalks (UGS) and fungi-treated grape stalks (Lentinula edodes, TGS) in rabbits’ diets. The control group was fed with a control diet without grape stalks (C), two experimental groups were fed on diets with 5% and 10% incorporation of UGS (5UGS and 10UGS), and two with 5% and 10% incorporation of TGS (5TGS and 10TGS). Rabbits fed with TGS diets showed higher daily weight gain (p = 0.034), feed conversion rate (p = 0.002), carcass weight (p = 0.038), and reference carcass weight (p = 0.03) when compared to the control diet. Moreover, animals fed with TGS diets showed an increase in the caecum (p = 0.015) and small intestine (p = 0.021) lengths and in the total volatile fatty acid content (p = 0.005) compared to animals fed UGS diets. Blood triglyceride levels were lower in animals fed with TGS diets compared to UGS (p = 0.005) and C (p ≤ 0.001) diets (12% and 19% lower, respectively), and a trend to lower cholesterol levels was observed (p = 0.071). Meat from rabbits fed with TGS diets had higher levels of linoleic acid, γ-linolenic, ∑ω-6, ∑PUFA, and ∑PUFA/∑SFA ratio compared to rabbits fed with the C diet. Results indicated that grape stalks (UGS and TGS) could be effectively used as an alternative raw material in rabbits’ diets without compromising animal performance.

Effects of cellulolytic treatment conditions on dietary fiber content of grape pomace and use of enzyme-treated pomace in cookie making

Grape pomace is a rich source of dietary fibers and phenolic compounds; it has been added to bakery products to enhance their dietary fiber content and antioxidant activity. Nevertheless, the Insoluble Dietary Fiber (IDF) content of grape pomace is significantly higher than the Soluble Dietary Fiber (SDF) content, the IDF/SDF ratio of bakery products was much higher than the recommended value of 3:1 from the dietetic associations. In this research, grape pomace was treated with cellulase preparation to partially convert IDF to SDF. The appropriate conditions of the cellulolytic treatment were as follows: initial moisture content of grape pomace of 7.5 g water/g dry basis, cellulase concentration of 6 U/g dry basis and treatment time of 1 h. Under these conditions, the SDF content increased by 20% and the IDF/SDF ratio decreased by 23.2%. Then, the enzyme-treated grape pomace (ETGP) and untreated grape pomace (UGPM) were separately mixed with wheat flour for cookie formulation; the grape pomace ratio was 20% of the composite flour weight. The use of ETGP or UTGP significantly improved the content of total, insoluble and soluble dietary fiber, total phenolics, anthocyanin of cookies as well as their antioxidant activity measured by DPPH and FRAP assays. Cookies supplemented with ETGP or UTGP had increased hardness and reduced brightness. The enzymatic treatment of grape pomace did not affect the total dietary fiber and antioxidant activity of cookies; however, their IDF/SDF ratio decreased to 12% and the value of 3.7 was close to the recommended ratio from the dietetic associations. Furthermore, the preference scores of ETGP added cookies and UTGP added cookies were higher than that of the control cookies without grape pomace addition.

Improvement of Must Fermentation from Late Harvest cv. Tempranillo Grapes Treated with Pulsed Light.

Pulsed light irradiation is a nonthermal technology currently used for the elimination of pathogens from a diverse range of food products. In the last two decades, the results obtained using PL at laboratory scale are encouraging wine experts to use it in the winemaking industry. PL can reduce native yeast counts significantly, which facilitates the use of starter cultures, reducing SO2 requirements at the same time. In this experimental set up, Tempranillo grapes were subjected to pulsed light treatment, and the fermentative performance of non-Saccharomyces yeasts belonging to the species Schizosaccharomyces pombe, Lachancea thermotolerans, Torulaspora delbrueckii, Metschnikowia pulcherrima and Hanseniaspora vineae was monitored in sequential fermentations against spontaneous fermentation and pure culture fermentation with the species Saccharomyces cerevisiae. The experimental analyses comprised the determination of anthocyanin (High performance liquid chromatography with photodiode array detector—HPLC-DAD), polyphenol index and colour (Ultraviolet-visible spectroscopy—UV-Vis spectrophotometer), fermentation-derived volatiles (Gas chromatography with flame ionization detector—GC-FID), oenological parameters (Fourier transform Infrared spectroscopy—FT-IR) and structural damage of the skin (atomic force microscopy—AFM). The results showed a decrease of 1.2 log CFU/mL yeast counts after pulsed light treatment and more rapid and controlled fermentation kinetics in musts from treated grapes than in untreated samples. The fermentations done with treated grapes allowed starter cultures to better implant in the must, although a larger anthocyanin loss (up to 93%) and an increase in hue values (1 unit) towards more yellow hues were observed for treated grapes. The development of biomass was larger in musts from treated grapes. The profile of volatile compounds and oenological parameters reveals that fermentations carried out with untreated grapes are prone to deviations from native microbiota (e.g., production of lactic acid). Finally, no severe damage on the skin was observed with the AFM on treated grapes.

Effects of Thermosonication, Sonication and Mild Heating on Organoleptic Attributes of Three Red Fruit Juices

Background: Colour and turbidity (appearance), odour and flavour, taste, and texture are the main parameters affecting consumer’s perception of juice quality. Anthocyanins, as natural antioxidant and water-soluble pigment, exist in red fruit juices which are extremely unstable and more susceptible to degradation. These mainly include anthocyanins, pigments, proteins, and vitamins that are thermally sensitive. Objective: The present study focuses on the treatment of three different fruit juices namely red grape, pomegranate, and sour cherry using different preservative methods and evaluation of their organoleptic properties. Methods: Four preservative methods including pasteurization (90°C for 30 sec), mild heat treatment (60°C for 4, 8 and 12 min), sonication (25°C) and thermosonication (90°C) using amplitude levels of 24.4, 42.7 and 61 μm for 4, 8 and 12 min, have been used for the treatment of the three selected fruit juices. Results: Obtained results indicate that untreated grape juice had maximum L* value (29.83) and the pasteurized grape juice had a minimum L* value (25.77). Furthermore, while a* values of untreated grape, pomegranate, and sour cherry juices were 39.7, 42.03 and 38.13, respectively, these pasteurized juices had minimum a* values of 35.3, 38.47 and 36.97, respectively. In addition, results revealed that sonication and mild heating had minimum effects on colour and appearance, odour and flavour of all three studied juices. Furthermore, significant positive (p˂0.05) effects of thermosonication were observed for the cloudiness parameter of the studied juices. Maximum acceptability scores were achieved by mild heat-treated grape juice at 60°C for 8 min (8.33), thermosonicated pomegranate juice at 60°C and amplitude of 24.4 μm for 4 min (7.33) and sonicated sour cherry juice at 25°C and amplitude of 24.4 μm for 4 min (9.33). Conclusion: Different preservative methods with optimum processing conditions were successfully utilized to minimize the changes in the sensorial and physicochemical properties of the treated juices.

Optimization of an abiotic elicitor (ultrasound) treatment conditions on trans-resveratrol production from Kalecik Karası (Vitis vinifera L.) grape skin.

Grapes are known to synthesize resveratrol, a stilbene phytoalexin, associated with cancer chemopreventive activity and cardioprotection. The effect of ultrasound (US) abiotic elicitor treatments on trans-resveratrol content in Kalecik Karası fresh and frozen grape skin was determined. D-optimal point change design was used under RSM for the experimental design of US treatment. The optimization was solved with the help of the Pareto areas and the optimal input variable values were determined by the desirability function with fuzzy similar perceivable ratio method. The optimum conditions of US treatment for fresh grape skin were determined as follows: incubation time-24h, US application method-(P01), US frequency-20kHz, US treatment time-60min and ultrasonic intensity (UI)-1.15 Wcm-2. The trans-resveratrol content (0.18 ± 0.01mg/g) in the untreated grape skin significantly increased with optimum US treatment (3.58 ± 0.08mg/g), increasing production to 19.9 times.

How Pre-Harvest Inactivated Yeast Treatment May Influence the Norisoprenoid Aroma Potential in Wine Grapes

Carotenoids are important secondary metabolites in wine grapes and play a key role as potential precursors of aroma compounds (i.e., C13-norisoprenoids), which have a high sensorial impact in wines. There is scarce information about the influence of pre-harvest inactivated yeast treatment on the norisoprenoid aroma potential of grapes. Thus, this work aimed to study the effect of the foliar application of yeast extracts (YE) to Negro Amaro and Primitivo grapevines on the carotenoid content during grape ripening and the difference between the resulting véraison and maturity (ΔC). The results showed that β-carotene and (allE)-lutein were the most abundant carotenoids in all samples, ranging from 60% to 70% of total compounds. Their levels, as well as those of violaxanthin, (9′Z)-neoxanthin, and 5,6-epoxylutein, decreased during ripening. This was especially observed in treated grapes, with ΔC values from 2.6 to 4.2-fold higher than in untreated grapes. Besides this, a principal components analysis (PCA) demonstrated that lutein, β-carotene, and violaxanthin and (9′Z)-neoxanthin derivatives principally characterized Negro Amaro and Primitivo, respectively. Thereby, the YE treatment has proved to be effective in improving the C13-norisoprenoid aroma potentiality of Negro Amaro and Primitivo, which are fundamental cultivars in the context of Italian wine production.

Evolution of Volatile and Phenolic Compounds during Bottle Storage of Merlot Wines Vinified Using Pulsed Electric Fields-Treated Grapes.

This study aimed to elucidate changes in volatile, phenolic, and oenological profiles of wines vinified from Pulsed Electric Fields (PEF)-treated and untreated Merlot grapes during bottle storage of up to 150, 90, and 56 days at 4 °C, 25 °C, and 45 °C, respectively, through chemometrics technique. Wines produced from untreated grapes and those PEF-treated at four different processing conditions (electric field strength 33.1 and 41.5 kV/cm and energy inputs between 16.5 and 49.4 kJ/kg) were used for the bottle storage study. Results showed that hydroxycinnamic and hydroxybenzoic acids in all stored wines, regardless vinified from untreated and PEF-treated grapes, increased as a function of time and temperature, while anthocyanins and selected esters (e.g., ethyl butanoate) decreased. Extreme storage temperature, at 45 °C particularly, resulted in a higher amount of linalool-3, 7-oxide in all stored wines. After prolonged storage, all wines produced from grapes PEF-treated with four different processing conditions were shown to favor high retention of phenolics after storage but induced faster reduction of anthocyanins when compared to wines produced from untreated grapes. Moreover, some volatiles in wines vinified using PEF-treated grapes, such as citronellol and 2-phenylethyl acetate, were found to be less susceptible towards degradation during prolonged storage. Production of furans was generally lower in most stored wines, particularly those produced from PEF-treated grapes at higher energy inputs (>47 kJ/kg). Overall, PEF pre-treatment on grapes may improve storage and temperature stability of the obtained wines.

The effect of ion-exchange resin treatment on grape must composition and fermentation kinetics

The aim of this study was to determine the influence of ion-exchange resin treatments of white grape must for the production of sparkling base wines, on the grape must chemical composition and fermentation kinetics. The experiment included an untreated grape must with a pH of 3.2, and resin-treated musts with pH 3.14, 3.07, and 3.01. Analysis of pH, total acidity, optical density (O.D.) at 420 nm, total phenolic content, tartaric acid, ammonium-nitrogen (AN) and cations (Ca2+, Mg2+, Cu2+, K+, and Na+) was performed. The fermentations were monitored by mass reduction (CO2 release g/L), and fermentation parameters obtained from a modified non-linear sigmoidal equation. The analyses of the musts showed differences in the concentration of metals, total acidity, tartaric acid, AN and O.D. 420 nm. The kinetic parameters of the fermentation showed significant changes between the control must and the ion-exchange treatments. This study showed that the treatment with cationic resins at the tested level significantly affects the chemical composition of the musts, interfering with the fermentation kinetics. In addition, reductions in the must pH index close to 0.1 unit can lead to positive results in the characteristics of the base must of sparkling wines.

PEF-dependency on polyphenol extraction during maceration/fermentation of Grenache grapes

Application to different electric field strengths (E) and specific energies (W) with the pulsed electric fields (PEF) technology on the rate of extraction of phenolic compounds during maceration/fermentation of Grenache grapes was studied. A response surface model between the total polyphenol index extraction rate (TPI) and the E and W of the PEF treatments was established, which permitted the determination of PEF processing conditions to achieve a certain TPI. To achieve a TPI of 50, treatments ranged from high intensity and short time (8 kV·cm−1 and 45 μs) to low intensity and long time (1 kV·cm−1 and 2800 μs) applying an optimum W of 4 kJ·kg−1 in all cases. The application of these PEF treatments reduced maceration time by a rate of 25 to 37% with respect to the untreated grape. Quality characteristics (color intensity, tannins, and total anthocyanins) were neither affected after fermentation nor after 12 months aging in bottles.

Nisin-Based Organic Acid Inactivation of Salmonella on Grape Tomatoes: Efficacy of Treatment with Bioluminescence ATP Assay

The antimicrobial activity of a new nisin-based organic acid sanitizer (NOAS), developed in our laboratory, was tested against viable aerobic mesophilic bacteria and Salmonella populations inoculated on produce surfaces. The activity of NOAS was compared with 200 ppm of chlorinated wash water and a bioluminescence ATP technique to determine the efficacy of treatments compared with plate count methods. The activity of the 10% final concentration of NOAS against viable populations of 109 CFU/mL Salmonella in phosphate-buffered saline (PBS), sterile deionized distilled water, and buffered peptone water was tested in vitro and on grape tomatoes inoculated with Salmonella at 2.5 log CFU/g. A similar batch of inoculated tomatoes were treated with 200 ppm of total available chlorinated water. All treatments for inactivation of viable Salmonella in vitro was tested up to 30 min and 5 min for the attached populations on tomatoes. Inactivation of viable Salmonella at 109 log CFU/mL by 10% the NOAS solution averaged >107 log CFU/mL in PBS, sterile deionized distilled water, and buffered peptone water. Similarly, Salmonella bacteria inactivated on tomato surfaces by the NOAS solution was significantly (P < 0.05) greater than numbers on chlorinated washed tomatoes, and surviving bacterial populations on NOAS and chlorine-treated tomatoes were <1 and 4 CFU/g, respectively. A significant linear correlation coefficient (r2 = 0.99) between the bioluminescence ATP assay and aerobic plate counts of inoculated and untreated grape tomatoes were recorded but not with NOAS and chlorine-treated tomatoes, as bacterial populations were less than the minimum baseline for determination. Also, the results indicated that the NOAS solution is a better alternative antimicrobial wash solution than 200 ppm of chlorinated water.

The impact of fungicide treatments on yeast biota of Verdicchio and Montepulciano grape varieties.

Yeast species that colonize the surface of grape berries at harvest time play an important role during the winemaking process. In this study, the use of culturable microbial techniques permitted a quantitative and qualitative inventory of the different yeast species present on the grape berry surfaces of Montepulciano and Verdicchio varieties when treated with conventional and organic fungicides. The results show that the most widespread yeast species at harvest time were Aureobasidium pullulans and Hanseniaspora uvarum, which are considered normal resident species and independent of the grape varieties and treatments applied. Specific differences when comparing the grape varieties were observed in species and were detected at a lower frequency; Pichia spp. were prevalent in Verdicchio, whereas Lachancea thermotolerans and Zygoascus meyerae were found in Montepulciano. In both vineyards, the farming treatments improved the competitiveness of A. pullulans, which was probably due to its reduced susceptibility to treatments that improved the competition toward other fungi. In contrast, the fermenting yeast H. uvarum was negatively affected by fungicide treatments and showed a reduced presence if compared with untreated grapes. Organic treatments directly impacted the occurrence of Issachenkia terricola in Montepulciano grapes and Debaryomyces hansenii and Pichia membranifaciens in Verdicchio. Conversely, a negative effect of organic treatments was found toward Metschnikowia pulcherrima and Starmerella bacillaris. Overall, the data suggest that the yeast community colonizing the grape berry surface was influenced by both grape variety and farming treatments, which characterized the yeast biota of spontaneous must fermentation.

Sensory attributes of wines made from vines of differing phosphorus status

Aim: The implications of water and nutrient deficiencies for photosynthesis, dry matter production, and yield have been well documented. However, whereas multiple studies show that water deficits affect grape and wine quality as well as wine sensory characteristics, the corresponding implications of manipulating vine nutrient status through fertilizer additions remain largely unexplored.Methods and results: In this study, phosphorus (P) fertilizers were applied to P-deficient vineyards of Cabernet Sauvignon, Chardonnay, and Chenin blanc growing in rhyolite, granite, and schist derived soils. Bloomtime leaf lamina P levels, basic soil chemical characteristics, juice P, and wine chemical parameters were measured after harvest. A highly sensitive protocol for sensory evaluation was used to test the wines made from the treated and untreated grapes for differences in wine appearance, flavor, aroma, and taste.&#x0D; All P additions were effective in rapidly increasing both vine P status and P in the harvested juice. In Cabernet Sauvignon vines growing on rhyolite, juice P was linearly related to vine P status compared to a non-linear accumulation of juice P in Chenin blanc vines growing on an calcium-rich schist soil. Soil CEC and Ca levels were both higher in the schist derived soil than in the rhyolite or granite soils, indicating a possible association of P release with soil parent material. Differences were detected in appearance, flavor, aroma, and taste in wines made from all three varieties on all three sites. Also, increasing vine P status increased the concentration of anthocyanins and soluble phenolics in the wines, and reduced fermentation time in the Cabernet Sauvignon.Conclusions: The results of this study show that vine P nutrient status can be manipulated by the grower across different soil types. Vine nutrient status has also been shown to significantly affect vine bud fertility, photosynthesis, dry matter and fruit production, and grape and wine chemical parameters. However, there is a lack of data describing the effect of manipulating vine nutrient status through fertilizer additions on the resulting wine sensory profile. Our results show that vine P status can influence the sensory attributes of wines.Significance and impact of the study: The results of this study and earlier work with vine water status identify two vineyard sources of variation in wine sensory attributes that occur both naturally and can be manipulated by the grower across different soil types.

Degradation of Azoxystrobin, Lufenuron and Fenpyroximate Residues in/on Grape Fruits under Field Conditions.

Fungal infection and pests attack arevery serious problems that facing grapes growers in Egypt. Fungicide azoxystrobin, (Azostar® 25%SC), insecticide lufenuron, (Cymax® 5%EC) and acaricide fenpyroximate (Ortus super® 5%EC) are the most common pesticides used to control such pests (downy mildew, grape fruit worm Eudemis botrana and red spider mite, respectively) in Egypt. The present study was carried out to assess persistence Vs. degradation behavior of the mentioned pesticides when sprayed on foliage of grape plants under field conditions during fruiting stage at the recommended and double the recommended rates of application during the season of 2017 in Adam village, El-Nobaria district, El-Behaira Governorate, Egypt. Fruit samples were collected randomly, two hours (initial time) and 1, 3, 7, 14 and 21 days after application. Samples of treated and untreated (control) grape fruits were prepared, extracted, cleaned-up by QuEChERS analytical method before quantification by high performance liquid chromatography with diode array detector (HPLC-DAD) and gas chromatography extended by electron capture detector (GC). The corresponding values for dissipation of the mentioned pesticides initial deposits, degradation percentages of residues, Residual Lifetime 50% (RL50), Residual Lifetime 90% (RL90) and pre-harvest intervals (PHIs) of the tested pesticides were determined. Results revealed that grape fruits remained higher initial amounts by (2.93 and 3.97), (0.82 and 1.14) and (1.74 and 1.94) mg kg-1 azoxystrobin, lufenuron and fenpyroximate for both doses, respectively. As for RL50, RL90 andPHIs, values showed (3.22, 1.73, 1.85 days) and (9.71, 4.22 and 6.31 days) and (5, 6.89, 4.05 days) when the recommended doses were applied and also, (3.80, 10.4 and 6.85 days) and (1.91, 5.02 and 7.12 days) and (2.58, 6.09 and 5.24 days) at the double recommended rates of application, in/on grape, respectively. In general, azoxystrobin, lufenuron and fenpyroximate residue in/on grape fruits had low persistence. In addition, the grape fruits could be consumed safely after 5, 6.89, 4.05 days, respectively from treating by the recommended rate of azoxystrobin, lufenuron and fenpyroximate when compared by the Maximum Residue Limits (MRLs) of the Codex Alimentarius Commission or the European Union (2, 0.01 and 0.01 mg kg-1), respectively.

Microwave assisted vacuum drying of thompson seedless grapes: Analysis of characteristics and kinetic modelling

A laboratory Microwave Assisted Vacuum Dryer (MAVD) was used in the present study to investigate the drying behaviour of Thompson seedless grapes under different microwave power levels, vacuum levels and thickness of grapes. It resulted in very low drying time as moisture diffusivity in grapes under MAVD process is few orders of magnitude more than that noted in sun-dried method. Drying kinetics study was done and the non-linear empirical model was found to be best fitted for describing the drying behaviour in this case. The effect of variation of process variables was studied and with respect to time efficiency and acceptable product quality, 400 mm Hg vacuum, 350 watt power and 1/3rd sliced grape samples provided best operating condition. Effect of hot and cold dipping pre-treatment on drying characteristics was also tested. Combination of ethyl oleate and K2CO3 as dipping solution (cold dip) worked best and gave lower drying time (13.454 min) than untreated grapes (23.19 min). Rehydration ratio and total soluble solid content (Brix value) were measured to indicate product quality of raisins. The rehydration ratio of dried seedless grapes was found to be 1.27±0.1 (without dipping) and 1.29±0.1 (with dipping) which are higher than the sun dried products. Brix value was obtained as 76.2 at 350 watt for 1/3rd sliced grapes, which is higher than the sun-dried raisin. Thus, results revealed that the MAVD process would be a promising alternative to conventional drying systems for raisin production within lesser time and with improved energy efficiency.