988 resultados para tomato pulp
Resumo:
Dissolving-grade pulps are commonly used for the production of cellulose derivatives and regenerated cellulose. High cellulose content, low content of non-cellulosic material, high brightness, a uniform molecular weight distribution and high cellulose reactivity are the key features that determine the quality of a dissolving pulp. The first part of this work was an optimization study regarding the application of selected enzymes in different stages of a new purification process recently developed in Novozymes for purifying an eucalypt Kraft pulp into dissolving pulp, as an alternative to the pre-hydrolysis kraft (PHK) process. In addition, a viscosity reduction was achieved by cellulase (endoglucanase) treatment in the beginning of the sequence, while the GH11 and GH10 xylanases contributed to boost the brightness of the final pulp. The second part of the work aimed at exploring different auxiliary enzyme activities together with a key xylanase towards further removal of recalcitrant hemicelluloses from a partially bleached Eucalypt Kraft pulp. The resistant fraction (ca. 6% xylan in pulp) was not hydrolysable by the different combinations of enzymes tested. Production of a dissolving pulp was successful when using a cold caustic extraction (CCE) stage in the end of the sequence O-X-DHCE-X-HCE-D-CCE. The application of enzymes improved process efficiency. The main requirements for the production of a dissolving pulp (suitable for viscose making) were fulfilled: 2,7% residual xylan, 92,4% of brightness, a viscosity within the values of a commercial dissolving pulp and increased reactivity.
Resumo:
Several models have been studied on predictive epidemics of arthropod vectored plant viruses in an attempt to bring understanding to the complex but specific relationship between the three cornered pathosystem (virus, vector and host plant), as well as their interactions with the environment. A large body of studies mainly focuses on weather based models as management tool for monitoring pests and diseases, with very few incorporating the contribution of vector's life processes in the disease dynamics, which is an essential aspect when mitigating virus incidences in a crop stand. In this study, we hypothesized that the multiplication and spread of tomato spotted wilt virus (TSWV) in a crop stand is strongly related to its influences on Frankliniella occidentalis preferential behavior and life expectancy. Model dynamics of important aspects in disease development within TSWV-F. occidentalis-host plant interactions were developed, focusing on F. occidentalis' life processes as influenced by TSWV. The results show that the influence of TSWV on F. occidentalis preferential behaviour leads to an estimated increase in relative acquisition rate of the virus, and up to 33% increase in transmission rate to healthy plants. Also, increased life expectancy; which relates to improved fitness, is dependent on the virus induced preferential behaviour, consequently promoting multiplication and spread of the virus in a crop stand. The development of vector-based models could further help in elucidating the role of tri-trophic interactions in agricultural disease systems. Use of the model to examine the components of the disease process could also boost our understanding on how specific epidemiological characteristics interact to cause diseases in crops. With this level of understanding we can efficiently develop more precise control strategies for the virus and the vector.
Resumo:
Tomato (Solanum lycopersicum L.) is an important vegetable crop and often cultivated in regions exposed to salinity and high temperatures (HT) which change plant architecture, decrease canopy light interception and disturb physiological functions. However, the long-term effects of salinity and HT combination (S+HT) on plant growth are still unclear. A dynamic functional-structural plant model (FSPM) of tomato was parameterized and evaluated for different levels of S+HT combinations. The evaluated model was used to quantify the contributions of morphological changes (architectural effects) and physiological disturbances (non-architectural effects) on the reduction of shoot dry mass under S+HT. The model predicted architectural variables with high accuracy (>85%), which ensured the reliability of the model analyses. HT enhanced architectural effects but reduced non-architectural effects of salinity on dry mass production. The stronger architectural effects of salinity under HT could not be counterbalanced by the smaller non-architectural effects. Therefore, long-term influences of HT on shoot dry mass under salinity were negative at the whole plant level. Our model analysis highlights the importance of plant architecture at canopy level in studying the plant responses to the environments and shows the merits of dynamic FSPMs as heuristic tools.
Resumo:
Tomato (Lycopersicon esculentum Mill.) is the second most important vegetable crop worldwide and a rich source of hydrophilic (H) and lipophilic (L) antioxidants. The H fraction is constituted mainly by ascorbic acid and soluble phenolic compounds, while the L fraction contains carotenoids (mostly lycopene), tocopherols, sterols and lipophilic phenolics [1,2]. To obtain these antioxidants it is necessary to follow appropriate extraction methods and processing conditions. In this regard, this study aimed at determining the optimal extraction conditions for H and L antioxidants from a tomato surplus. A 5-level full factorial design with 4 factors (extraction time (I, 0-20 min), temperature (T, 60-180 •c), ethanol percentage (Et, 0-100%) and solid/liquid ratio (S/L, 5-45 g!L)) was implemented and the response surface methodology used for analysis. Extractions were carried out in a Biotage Initiator Microwave apparatus. The concentration-time response methods of crocin and P-carotene bleaching were applied (using 96-well microplates), since they are suitable in vitro assays to evaluate the antioxidant activity of H and L matrices, respectively [3]. Measurements were carried out at intervals of 3, 5 and 10 min (initiation, propagation and asymptotic phases), during a time frame of 200 min. The parameters Pm (maximum protected substrate) and V m (amount of protected substrate per g of extract) and the so called IC50 were used to quantify the response. The optimum extraction conditions were as follows: r~2.25 min, 7'=149.2 •c, Et=99.1 %and SIL=l5.0 giL for H antioxidants; and t=l5.4 min, 7'=60.0 •c, Et=33.0% and S/L~l5.0 g/L for L antioxidants. The proposed model was validated based on the high values of the adjusted coefficient of determination (R2.wi>0.91) and on the non-siguificant differences between predicted and experimental values. It was also found that the antioxidant capacity of the H fraction was much higher than the L one.
Resumo:
p.73-78
Resumo:
Tomato (Lycopersicon esculentum L.) is the second most important vegetable crop worldwide and a key component in the so-called “Mediterranean diet”. In the Northeastern region of Portugal, local populations still prefer to consume traditional tomato varieties which they find very tasty and healthy, as they are grown using extensive farming techniques. A previous study of our research team described the nutritional value of the round (batateiro), long (comprido), heart (coração) and yellow (amarelo) tomato varieties [1], but the phenolic profile was unknown until now. Thus, the objective of this study was to characterize the phenolic profiles of these four tomato farmers’ varieties by using HPLC-DAD-ESI/MS and evaluate its antioxidant capacity through four in vitro assays based on different reaction mechanisms. A cis p-coumaric acid derivative was the most abundant compound in yellow and round tomato varieties, while 4-O-caffeolyquinic acid was the most abundant in long and heart varieties. The most abundant flavonoid was quercetin pentosylrutinoside in the four tomato varieties. Yellow tomato presented the highest levels of phenolic compounds, including phenolic acids and flavonoids, but the lowest antioxidant activity. In turn, the round tomato gave the best results in all the antioxidant activity assays. This study demonstrated that these tomato farmers’ varieties are a source of phenolic compounds, mainly phenolic acid derivatives [2], and possess high antioxidant capacity [1]; being thus key elements in the diet to prevent chronic degenerative diseases associated to oxidative stress, such as cancer and coronary artery disease.
Resumo:
The aim of this monograph is the attempt of reading the poem Moscow-Petushki by Venedikt Erofeev and the film Pulp Fiction by Quentin Tarantino using the comparative approach, in which we go beyond the range of factual relationships, historical influences or similarities functioning in the structure of the presented world. The purpose of the book is to see both works of art from the angle of the montage theory of Sergei Eisenstein – the outstanding and highly regarded Russian director and film philosopher – which means studying cultural phenomena in their mutual intertextual relationships. The book focuses on the interpretation of the selected Tarantino’s and Erofeev’s texts of culture, in which the subject of the city, the search for the concept of the body at the end of 20th century and the problem of addictions constitute the dominant thematic issues. The monograph also offers the insight into the nature of the phenomenon of postmodernism and treats Eisenstein’s philosophy as the specific type of anticipation of postmodern tendencies in cinematography.
Resumo:
Tomato is the second most important vegetable crop worldwide and a rich source of industrially interesting antioxidants. Hence, the microwave-assisted extraction of hydrophilic (H) and lipophilic (L) antioxidants from a surplus tomato crop was optimized using response surface methodology. The relevant independent variables were temperature (T), extraction time (t), ethanol concentration (Et) and solid/liquid ratio (S/L). The concentration-time response methods of crocin and β-carotene bleaching were applied, since they are suitable in vitro assays to evaluate the antioxidant activity of H and L matrices, respectively. The optimum operating conditions that maximized the extraction were as follows: t, 2.25 min; T, 149.2 ºC; Et, 99.1 %; and S/L, 45.0 g/L for H antioxidants; and t, 15.4 min; T, 60.0 ºC; Et, 33.0 %; and S/L, 15.0 g/L for L antioxidants. This industrial approach indicated that surplus tomatoes possess a high content of antioxidants, offering an alternative source for obtaining natural value-added compounds. Additionally, by testing the relationship between the polarity of the extraction solvent and the antioxidant activity of the extracts in H and L media (polarity-activity relationship), useful information for the study of complex natural extracts containing components with variable degrees of polarity was obtained.
Resumo:
The production of natural extracts requires suitable processing conditions to maximize the preservation of the bioactive ingredients. Herein, a microwave-assisted extraction (MAE) process was optimized, by means of response surface methodology (RSM), to maximize the recovery of phenolic acids and flavonoids and obtain antioxidant ingredients from tomato. A 5-level full factorial Box-Behnken design was successfully implemented for MAE optimization, in which the processing time (t), temperature (T), ethanol concentration (Et) and solid/liquid ratio (S/L) were relevant independent variables. The proposed model was validated based on the high values of the adjusted coefficient of determination and on the non-significant differences between experimental and predicted values. The global optimum processing conditions (t=20 min; T=180 ºC; Et=0 %; and S/L=45 g/L) provided tomato extracts with high potential as nutraceuticals or as active ingredients in the design of functional foods. Additionally, the round tomato variety was highlighted as a source of added-value phenolic acids and flavonoids.
Resumo:
Tomato ( Lycopersicon esculentum Mill) is the leading vegetable in terms of production in Kenya. The Kenyan local market has a wide variety of tomato cultivars with a wide range of morphological and sensorial characteristics. However, information on the nutritional and postharvest quality of these varieties is lacking. The aim of this research was to investigate and identify tomato varieties of superior postharvest quality and recommend them to small and medium scale farmers. In this study, six tomato varieties were grown in a greenhouse and analyzed at three maturity stages (mature green, turning and red ripe). The tomatoes were analyzed at specific days after harvest and storage at room temperature (25o C). Percentage weight loss, color, respiration and ethylene production rates were analyzed to assess the postharvest quality of the tomatoes. The color was measured using a Minolta Chromameter while the respiration rate and ethylene production rates were determined using the static system approach. Color, weight loss, respiration and ethylene production rates were positively affected by storage time when harvested at the three maturity stages. The percentage weight loss of the tomato fruits was higher in the determinate varieties, and at the turning stage of maturity (3.8 %). Minor color changes were observed after storage of the tomatoes harvested at red stage for six days. Both rates of respiration and ethylene production were low, with the respiration rate ranging between 56-10 ml CO2 Kg-1h-1. The Chonto F1 variety had the highest rate of ethylene production (5.4 μL C2H4 Kg-1h-1) on the 4th day of storage after harvest at the red ripe stage. Overall, the indeterminate tomato varieties displayed better postharvest quality that can prolong the fruits shelf life for marketing. In turn, the turning stage of maturity proved to be a better stage to harvest tomatoes as the color development was more uniform.
Resumo:
The growing concerns for physical wellbeing and health have been reflected in the way we choose food in our table. Nowadays, we are all more informed consumers and choose healthier foods. On the other hand, stroke, cancer and atherosclerosis may be somehow minimized by the intake of some bioactive compounds present in food, the so-called nutraceuticals and functional foods. The aim of this work was to make a revision of the published studies about the effects of some bioactive compounds, namely lycopene in human health, in the prevention of diseases, thus playing the role of a functional food. Free radical in human body can induce cell damage and consequently can be responsible for the development of some cancers and chronic diseases. Lycopene is one of the most powerful antioxidants known, being the predominant carotenoid in tomato. The respective chemistry, bioavailability, and its functional role in the prevention of several diseases will be object of this work. On the other hand, the inclusion of lycopene in some foods can also be made by biotechnology and represents a way to recover the wastes in the tomato industry with nutritional positive effects in health.
Resumo:
Scarcity of freshwater due to recurrent drought threatens the sustainable crop production in semi-arid regions of Ethiopia. Deficit irrigation is thought to be one of the promising strategies to increase water use efficiency (WUE) under scarce water resources. A study was carried out to investigate the effect of alternate furrow irrigation (AFI), deficit irrigation (DI) and full irrigation (FI) on marketable fruit yield, WUE and physio-chemical quality of four fresh-market tomato cultivars (Fetan, Chali, Cochoro and ARP Tomato d2) in 2013 and 2014. The results showed that marketable yield, numbers of fruits per plant and fruit size were not significantly affected by AFI and DI irrigations. WUE under AFI and DI increased by 36.7% and 26.1%, respectively with close to 30% irrigation water savings achieved. A different response of cultivars to irrigation treatments was found for marketable yield, number of fruits and fruit size, WUE, total soluble solids (TSS) of the fruit juice, titratable acids (TA) and skin thickness. Cochoro and Fetan performed well under both deficit irrigation treatments exhibited by bigger fruit size which led to higher WUE. ARP Tomato d2 showed good yields under well-watered conditions. Chali had consistently lower marketable fruit yield and WUE. TSS and TA tended to increase under deficit irrigation; however, the overall variations were more explained by irrigation treatments than by cultivars. It was shown that AFI is a suitable deficit irrigation practice to increase fresh yield, WUE and quality of tomato in areas with low water availability. However, AFI requires suitable cultivars in order to exploit its water saving potential.
Resumo:
Understanding the variation in physiological response to deficit irrigation together with better knowledge on physiological characteristics of different genotypes that contribute to drought adaptation mechanisms would be helpful in transferring different irrigation technologies to farmers. A field experiment was carried to investigate the physiological response of four tomato cultivars (Fetan, Chali, Cochoro and ARP Tomato d2) to moderate water deficit induced by alternate furrow irrigation (AFI) and deficit irrigation (DI) under semi-arid condition of Ethiopia during 2013 and 2014. The study also aimed at identifying physiological attributes to the fruit yield of tomato under different deficit irrigation techniques. A factorial combination of irrigation treatments and cultivar were arranged in a complete randomized design with three replicates. Results showed that stomatal conductance (g_s) was significantly reduced while photosynthetic performance measured as chlorophyll fluorescence (Fv’/Fm’), relative water content (RWC) and leaf ash content remained unaffected under deficit irrigations. Significant differences among cultivars were found for water use efficiency (WUE), g_s, chlorophyll content (Chl_SPAD), normal difference vegetation index (NDVI), leaf ash content and fruit growth rate. However, cultivar differences in WUE were more accounted for by the regulation of g_s, therefore, g_s could be useful for breeders for screening large numbers of genotypes with higher WUE under deficit irrigation condition. The study result also demonstrated that cultivar with traits that contribute to achieve higher yields under deficit irrigation strategies has the potential to increase WUE.
Resumo:
This study aimed to evaluate the e ect of diets containing increasing levels of citrus pulp on the physic-chemical and microbiological characteristics of horses feces. Five mares, at an average age of 3.5 years old and body weight of 492 ± 44.5 kg were arranged in a 5 x 5 Latin Square. The experimental diet consisted of 60% coast-cross hay and 40 % of concentrate with increasing levels of citrus pulp (0, 7, 14, 21, and 28 %). To determine the fecal pH, samples were collected directly from the oor, immediately after defecation, in the rst feces the day at 07:00 a.m., and color and fecal consistency were evaluated. For microbiological analysis, an aliquot was reserved in plastic bags, frozen, and sent to the microbiological laboratory for further analysis. Lactic acid bacteria were counted for Lactobacillus spp. and Streptococcus spp. from fecal samples under anaerobic conditions. The diet produced di erences (P<0.05) in feces consistency 98% had normal and rm stools, while 2% had loose ruminant-type feces. We observed no di erence (P<0.05) for color, verifying 100% of greenish feces, normal for equines. There was no e ect (P>0.05) on pH and on the number of Lactobacillus spp. and Streptococcus spp. The inclusion of up to 28% citrus pulp concentrates for horses did not promote change in the physio-chemical characteristics and on the population of lactic acid-producing bacteria in feces.
Resumo:
In this context, the objective of this work was to evaluate the performance of mini tomato cultivars of determinate growth habit, in two crop seasons in the conditions of the Sub-Mid São Francisco Valley, Brazil.