Dry Tomato Research Articles

The influence of the combined microwave power and hot air ventilation on the drying kinetics and colour quality of tomato slices

Tomato is one of the most important fruit used as an ingredient in different foods in food processing and preparation. Fresh tomato consists of about 91% of moisture. Tomato has to pass through all three rates of drying (constant, first and second falling rate period) during drying, using hot air ventilation, and requires prolonged time with much of quality changes. In this study, microwave assisted hot air ventilation drying of tomato slices had been considered. Microwave oven working at 2450 MHz, using different power densities (1, 2 and 3 W g -1 ) was combined with hot air ventilation at 50°C and hot air ventilation drying without microwave power at 40, 50, 70 and 80°C to dry tomato slices down to 10% moisture content. The drying characteristic curve was analyzed to determine the drying time. The tomato slice sample dried faster when subjected to microwave heating, coupled with hot air ventilation at 50°C. The drying times required for tomato slices to reach 10% moisture content were found to be 3.2, 2.5 and 1.3 h, using 1, 2 and 3 W g -1

Diffuse Solar System Design and Utilization in Agriculture and Domestic Applications

Diffuse solar radiation is a component of total solar radiation that is good for low temperature grade heating. Since the portion of the scattered radiation from the sun, which consists of short and long waves, that reaches the earth is diffused, its utilization in Agriculture as this paper suggested, has multiple phase change material, which as well could serve as heat exchange for domestic (residential) applications. The Diffuse Solar System designed, consists of three functional units: the solar collector, thermal storage (heat sink) and a dryer cabinet. The thermal storage ranges from 140 – 1500F (60 – 500C) for heating system and 60 – 700F (15 – 200C) for residential cooling. Likewise, a natural convection solar dryer with collector efficiency of about 42% and drying efficiency of about 53% would dry tomatoes with initial moisture contents of 94% wet basis, to safe moisture content of about 4% wet basis and 35.2 – 86.8% ascorbic acid (vitamin C) retention with acceptable colour and texture. Keywords: Solar radiation, Heat sink, Ascorbic acid, Collectors, Reflectors, Yeast/mould count and Efficiency.

Thermal diffusivity of periderm from tomatoes of different maturity stages as determined by the concept of the frequency-domain open photoacoustic cell

The frequency-domain open photoacoustic cell (OPC) approach was used to determine room temperature thermal diffusivity of skins (pericarps) from the raw tomatoes (Lycopersicon esculetum Mill.) characterized by the three different stages of ripeness (from immature-green to a mature-red). Periodically interrupted 532 nm laser radiation was used to heat the dry tomato skins, typically 10 mm in diameter and up to 68 μm thick; the modulating frequency f varied from 8 to 150 Hz. Initially, a combined OPC-model that takes into account both, the thermoelastic bending and the effect of thermal diffusion (TD), has been applied. Preliminary results showed that until at least 40 Hz, the effect of TD dominates; above this value the combined model fits the experimental data only poorly. For this reason a less complex OPC-TD approach was applied to all investigated skins instead, which predicts an exponential decrease for the amplitude of measured photoacoustic signal S with increasing f. For a specimen that is simultaneously opaque and thermally thick, S depends on f as S∼exp(−b f1/2) where b is a fitting parameter. The S versus f plot enables one to deduce the numerical value for b which, on its turn allows for the assessment of skin’s thermal diffusivity α. Thermal diffusivities obtained for the immature green, orange, and red skins (periderms) are 9.9×10−8 m2 s−1, 7.2×10−8 m2 s−1, and 4.6×10−8 m2 s−1, respectively; the uncertainty was typically 5% of the measured value.

Effect of extraction parameters on the carotenoid recovery from tomato waste

Tomato waste is an important source of natural carotenoids. This study was carried out to assess the extractability of tomato waste carotenoids in different organic solvents and to optimise the extraction parameters (type of solvent, extraction time, temperature and extraction steps) for maximum yield. Among other solvents, we tested a new environmentally friendly one, ethyl lactate, which gave the highest carotenoid yield (243.00 mg kg -1 dry tomato waste) at 70 °C, compared to acetone (51.90 mg kg -1 ), ethyl acetate (46.21 mg kg -1 ), hexane (34.45 mg kg -1 ) and ethanol (17.57 mg kg -1 ). The carotenoid recovery was significantly (P < 0.05) affected by the number of extraction steps and temperature in all solvents. Mathematic equations predicted rather satisfactorily (R 2 = 0.89-0.93) the rate of carotenoid extraction in the above-mentioned solvents. Carotenoid concentration increased with time, approaching a quasi-saturated condition at approximately 30 min of extraction.

Enhanced Lycopene Recovery from Tomato Processing Waste by Enzymatic Degradation of Plant Tissue Components

Eight commercial enzyme preparations with pectinolytic, cellulolytic, hemicellulolytic and proteolytic activities were tested for their ability to enhance lycopene extraction from tomato peels. Screening experiments were performed at 40 °C by subjecting the peels to a 1-h enzyme incubation followed by 1-h hexane extraction. The resulting yields were between 51 and 195.9 mg of lycopene per 100 g of dry tomato peels, while the value obtained for the untreated peels was 23.7 mg /100 g. Synergistic and antagonist effects were observed when different enzyme products were used in 50:50 (v/v) combination. The preparations richest in cellulase and pectinase were the most efficient, with an up to 10-fold increase in extraction yield. A statistical analysis of factors affecting lycopene extraction revealed that enzyme dosage was the most influential, followed by temperature and enzyme incubation time. A strong interaction was also found between the latter two variables

Effects of Dry Tomato Pulp on Egg Yolk Pigmentation and Some Egg Yield Charecteristics of Laying Hens

Effects of Dry Tomato Pulp on Egg Yolk Pigmentation and Some Egg Yield Charecteristics of Laying Hens

Effects of irradiation and storage on the physico‐chemical and sensory properties of hamburgers enriched with lycopene

SummaryIn order to increase their safety and shelf‐life, raw hamburgers containing 30, 45 and 60 g kg−1 dry tomato peel (DTP) as a source of lycopene were manufactured, vacuum‐packed and irradiated with 2 or 4 kGy. The effects of this treatment on microbial load, lycopene concentration, physico‐chemical and sensory properties were studied during 17 days of refrigerated storage. After irradiation with 4 kGy and 17 days of storage, microbial levels fell, four logarithmic cycles and the lycopene concentration fell to 15% of the initial value. Even with this decrease, hamburgers containing 6% DTP had a final lycopene concentration of 7.14 mg per 100 g of hamburger, an amount very close to the recommended daily intake for a healthy diet. DTP masks the brownish colour characteristic of irradiated meat, and 6% DTP gives to the hamburger similar redness (a* parameter), independently of the dose of radiation applied. Sensory characteristics were influenced by irradiation, but the higher lycopene concentration (6 g kg−1) masked these changes sufficiently to assure an acceptable colour and odour in the final product after the storage period.

Beef hamburgers enriched in lycopene using dry tomato peel as an ingredient

The direct addition of dry tomato peel (DTP) to hamburgers may be useful both to obtain a new product enriched in lycopene and for providing a use for this by-product from the tomato industry. In this study, different amounts of DTP (0–6.0% w/w) were added to raw and cooked hamburgers, and the effects on the meat’s physico–chemical and sensorial characteristics were studied. The maximum DTP concentration compatible with good sensory acceptability and high lycopene content was determined. Addition of DTP increased the colour parameters a ∗ and b ∗ of raw and cooked hamburgers, and modified all textural properties probably because of the presence of fibre. The hardness values of cooked samples was significantly higher in the batch containing 6% DTP (67.6 N) than in a control batch (50.9 N, p < 0.05). The addition of DTP to 4.5% results in hamburgers with good overall acceptability and a lycopene content of 4.9 mg/100 g of cooked hamburger.

Change in color and other fruit quality characteristics of tomato cultivars after hot-air drying at low final-moisture content

The present study aimed to evaluate the drying quality of three tomato cultivars (Amoroso, Berlinto and Messina) at low final-moisture content. Tomatoes were cut into slices and hot-air-dried from 92% (wet basis) to 12% final moisture content at 55°C, 65°C and 75°C at 1.5 m/sec air flow. Color, total soluble solids (TSS), titratable acidity (TA) and ascorbic acid (AA) content were measured in both fresh and dried tomatoes. Brightness of the dried tomato slices was significantly decreased, while intensity of the red and yellow colors and brightness of the red color (a*/b*) increased. Low overall color change (ΔE) was obtained at the lowest drying temperature (55°C). Messina and Amoroso showed a higher a* value and lower ΔE, respectively. The TSS content was increased, while the TA and AA contents were decreased through drying. This study shows that it is possible to hot-air dry tomato slices to a final moisture content of 12% maintaining quality that is comparable with studies where the final-moisture content was higher (15% or more).

NMR characterization of hydration and thermal stress in tomato fruit cuticles

In its natural environment, the plant cuticle, which is composed of the biopolymer cutin and a mixture of surface and embedded cuticular waxes, experiences a wide variety of temperatures and hydration states. Consequently, a complete understanding of cuticular function requires study of its thermal and mechanical properties as a function of hydration. Herein, we report the results of a comprehensive 13C nuclear magnetic resonance (NMR) relaxation study of hydrated tomato fruit cuticle. Cross-polarization and direct-polarization experiments serve to measure the solid-like and liquid-like components, respectively, of hydrated cuticle. Localized, high-frequency motions are probed by T 1(C) spin relaxation measurements, whereas T 1ρ(H) and T 1ρ(C) experiments reflect low-frequency, lower amplitude polymer-chain motions. In addition, variable-temperature measurements of T 1(C) and T 1ρ(C) for dry tomato cuticles are used to evaluate the impact of temperature stress. Results of these experiments are interpreted in terms of changes occurring in individual polymer motions of the cutin/wax components of tomato cuticle and in the interaction of these components within intact cuticle, both of which are expected to influence the functional integrity of this protective plant covering.

Drying Characteristics, Sorption Isotherms, and Lycopene Retention of Tomato Pulp

Tomato pulp separated by centrifugation of crushed tomatoes was dried in cabinet, tray, fluidized-bed, and freeze dryers at 50–70°C using 4–12 kgm−2 tray loads. Drying behavior was well described by the Page's model with coefficient of determination greater than 0.99 and standard error of 0.004–0.019. A fluidized-bed dryer was more efficient to dry tomato pulp than tray, freeze, and cabinet dryers. Retention of lycopene in tomato pulp was maximum in a freeze dryer (72.483–78.093 mg 100 g−1) followed by fluidized-bed (42.273–57.926 mg 100 g−1), cabinet (35.532–49.271 mg 100 g−1) and tray dryer (24.454–45.842 mg 100 g−1) under experimental conditions (tray load 4–12 kgm−2, temperature 50–70°C). The moisture sorption isotherms of tomato pulp obtained by equilibrating saturated salts solution of known water activity (0.113–0.92) at 30–60°C were sigmoid. A modified Henderson model was the best model for the tomato pulp with coefficient of determination more than 0.99 and standard error less than 0.270. The net isosteric heat of sorption, estimated using the Clausius-Clapeyron equation, was 21.451–5.541 Jmol−1 at 25–5% moisture content (dry basis).

Improved lycopene extraction from tomato peels using cell-wall degrading enzymes

Four commercial enzyme preparations with pectinolytic, cellulolytic and hemicellulolytic activities were tested for their ability to enhance lycopene extraction from tomato peels. Screening experiments were performed at 25 °C by subjecting the peels to a 4-h enzyme incubation followed by 1-h hexane extraction. Peclyve EP and LI were the most efficient, with an almost 20-fold increase in extraction yield. Peclyve LI was used to evaluate the influence of solvent type and enzyme incubation time on lycopene recovery. Hexane, ethyl acetate and the mixture hexane/acetone/ethanol 50:25:25 (v/v) were used as solvents. Under the best extraction conditions (1-h enzyme incubation followed by a 3-h solvent extraction at 40 °C) up to 440 mg of lycopene per 100 g of dry tomato peels were obtained. The percentage recoveries were in the range of 3–30%, for the untreated peels, and 77–98% for the enzymatically treated material.

Dry fermented sausages enriched with lycopene from tomato peel

Tomato industries yield a high amount of by-products mainly tomato peel and seeds. Since tomato peel is rich in lycopene, the direct addition of peel to food products could be a way to use this by-product to obtain a new products enriched in lycopene. This work describes experiments performed to develop dry fermented sausages (salchichón) containing this carotene. 0%, 0.6%, 0.9% and 1.2% (w/w) of dry tomato peel was added to the meat mixture used in sausage manufacture. A slight losts of lycopene was detected after 21 days ripening, however, levels remained between 0.26 and 0.58mg of lycopene/100g of sausage. The sensory and textural properties and overall acceptability of all sausages were good, indicating that tomato peel could be added to dry fermented sausages to produce a meat product enriched in lycopene.

Sorption Isotherms and Drying Characteristics of Tomato Peel Isolated from Tomato Pomace

Tomato peel was separated from pomace by sedimentation and dried in cabinet and fluidized-bed dryer at 50–70°C using 4–12 kg/m2tray load. The drying of tomato peel took place under the falling rate period and the drying behavior was well described by Page's model with coefficient of determination greater than 0.99 and standard error of 0.003–0.016. A fluidized-bed dryer was much more efficient than a cabinet dryer to dry tomato peel. The moisture adsorption isotherms of tomato peel were obtained by equilibrating above saturated salt solutions of known a w (0.113–0.92) at 20–60°C. The data were analyzed using fifteen sorption models based on coefficient of determination, standard error, and residual plots. Modified Henderson was the best model for tomato peel with coefficient of determination >0.99, standard error <0.210, and a scattered residual plot. The net isostearic heat of sorption, estimated using the Clausius-Clapeyron equation, was 0.74–23.23 kJ/mol at 2.0–2.5% moisture content (dry basis).

ENERGY SCREENS IN TOMATO: DETERMINING THE OPTIMAL OPENING STRATEGY

In general, the use of energy screens is a good means to reduce the energy consumption and to lower peaks in energy use in greenhouse horticulture. In tomato, experience with screens is limited since the use of screens is not so widespread as in other fruit vegetable crops. In this study effects of different screen opening strategies on greenhouse climate, energy consumption and crop production were quantified by means of an experiment and model calculations. In the experiment, two treatments were compared, i.e. opening the energy screen (SLS 10 Ultra plus) at 5 or at 50 W m-2 outside global radiation. Plant dry weights and tomato production did not differ between the treatments. Due to the larger number of screening hours, energy consumption in the 50 W m-2 treatment was 3.5% lower during the experiment than when screens were opened at 5 W m-2. With a greenhouse climate model and a crop growth model, effects of different screen opening criteria on greenhouse climate, energy consumption and crop growth were simulated. Application of a screen during the night reduced the energy consumption by 16% without affecting crop production. When screens were opened at higher levels of outside global radiation (up to 150 W m-2), energy consumption decreased by 1.6 m3 gas m-2 year-1 and crop production by 0.3 kg m-2 year-1. Financial considerations between energy saving and production loss were discussed. Screen opening based on a combination of global radiation and outside air temperature reduced the energy use, but increased the number of hours with high humidities. Screen opening based on the temperature difference below and above the screen performed comparable to the temperature and light strategy. Opening the screen caused a temporarily decrease in greenhouse air temperature. Increasing the number of opening steps before the screen was opened completely, decreased this temperature drop. This study provides growers with information to determine their screening strategy. However, screen use could be further optimized by offering growers a decision support tool that, given outside weather conditions and prices of gas and tomatoes, gives daily advice on the optimal moment of screen opening.

Survival of plant pathogens under structural solarization

Structural solarization of greenhouses is a nonchemical sanitation procedure. The method involves dry heating, since maximal temperatures may exceed 60°C and consequent relative humidity (r.h.) is low (ca 15%), under fluctuating temperature and r.h. regimes. Thirty-five structural solarization experiments were performed over 7 years, testing one bacterial and five fungal plant pathogens. Various aspects of pathogen thermal inactivation under this method were studied. Thermal inactivation of the various pathogens differed according to the organism and inoculum form. Sensitivity to heat was highest withClavibacter michiganensis subsp.michiganensis and lowest withFusarium oxysporum f.sp.radicislycopersici inoculum in dry infected tomato stems, with ED80 values of 7 and 47 days, respectively; intermediate values were obtained forPythium sp.,F. oxysporum f.sp.melonis, F. oxysporum f.sp.basilici andSclerotium rolfsii. The maximal ambient temperatures were in the range of 28.2° to 33.1°C. Structural solarization for sanitation can be a useful component of integrated pest management in greenhouses.

トマト「ファースト」より育成した雄性不稔突然変異３系統の花粉崩壊と遺伝様式

Three types of male sterile mutants were induced by irradiation of dry tomato seeds of cv. First with gamma rays. The mutants are characterized by : a) pollen degradation process, b) morphorogical differences in the floral organs and c) anther colour. Their genetic systems were also investigated. One group of male sterile mutants developed normal pistil and stamen with yellow anther, and thus this type was indistinguishable from the non-irradiated (control) plants even at flowering stage. Pollen degradation of this type (T-1) became evident at micro-sporogenesis. The second one was morphologically distinguishable by an exserted style because of a degenerating anther which became yellow-brown acropetally. Pollen degradation of this type (T-2) became evident around meiosis stage. The third one developed normal pistil and stamen with yellow anther, similar to those in T-1. However, the pistil became longer than the stamen a few days before anthesis, and top of staminal-corn split at anthesis so that the stigma was disclosed. Pollen degradation of this type (T-3) became evident from tetrad to early microspore stages. For each type, when heterozygous plants, Msms, was selfed, fertile and sterile progenies in the M2 and M3 generations segregated at a ratio of 3 : 1. The fertile and sterile progenies from a testcross between sterile, msms, and heterozygous plants, Msms, segregated at a ratio of 1 : 1. These results indicate that the three types of male sterility are controlled by a single recessive gene.

Comparison of nuclear replication activity and protein expression patterns during tomato seed germination

Abstract Flow cytometric determination of DNA amounts in embryos of fully matured dry tomato (Lycopersicon esculentum Mill.) seeds revealed mainly 2C signals. Apparently, most embryonic cells had arrested the cell cycle activity during maturation at the presynthetic G1 phase of nuclear division. During imbibition of tomato seeds, both in water and in PEG solution, an augmentation in the 4C signal of tissues at the embryonic root tip region occurred. This increase was found to be related to cells entering the synthetic phase of nuclear division leading to a doubling of the chromosomal material. In the root tip cells, 4C 2C ratios rose 1 day after imbibition in water while radicle emergence started 2 days later. Apparently, DNA synthesis preceded germination. The induction of nuclear activities was compared with changes in protein expression patterns during seed imbibition. Using chemiluminescent immunodetection after Western blotting, we identified changes in β-tubulin expression during germination and priming of tomato seeds. Tubulin was found to be synthesized 8 h after the start of imbibition both in water and in PEG. The start of tubulin synthesis considerably preceded DNA replication, cell division and germination. The induction of cell cycle activities may be an early indicator of the initiation of cell division and the start of germination.

The Peasant Connection: A Case Study of the Bureaucracy of Agri-Industry

The paper deals with development at the rural peasant level reviewing a scheme for introducing dry season tomato farming to Zaria area villages. Project participants are obligated to give their crop to Cadbury's for processing into tomato puree. Farmers are docked price to pay for services rendered, and in response they have sold most of their crop on the open market. Villages vary in the amount of tomatoes they do deliver to the monopoly company. Using a random sample of participating farmers in five villages plus a control group it is found that the project does increase farm incomes. Leadership and attitudes to leadership per village are significantly associated with variance in delivery of tomatoes to the Company. Unless there are previously solidary relations between peasants and the traditional authorities they are mistrusted. Contrarily, leaders who are elected by the people themselves are most trusted and their organization cooperates to deliver more tomatoes to the nascent industry. It is recomme...

Effect of various sugar solution concentrations on characteristics of dried candy tomato (Lycopersicum esculentum)

Abstract. Buntaran W, Astirin PA, Mahajoeno M. 2009. Effect of various sugar solution concentrations on characteristics of dried candy tomato (Lycopersicum esculentum). Nusantara Bioscience 2: 55-61. The aims of the research were to study the effects of sugar syrup concentration on dried candy tomato characteristics and to determine the proper sugar solution concentration that gives the best characteristics of dry candy tomatoes. The research used Randomized Block Design Method with four treatments and six times repetitions. The treatment that be used was immersing the tomato in sugar solution, with concentration of A (40%), B (50%), C (60%), and D (70%) group in 18 hours. The variables measured were water content, ash, vitamin C and organoleptic tests include flavor, color, flavor and texture test. Data were analyzed using ANOVA test (Analysis of Variance) followed by DMRT (Duncan Multiple Range Test). The result showed that sugar solution concentration had different effect on water content, ash content, vitamin C content, texture, and organoleptic test for color, taste, and flavor of the dry candy tomato. The best characteristics of dry tomato candy was obtained on A (40%) group, with water content of 24.20%, ash content of 0.62%, and vitamin C content of 31.15 mg/100 g. Standard quality of water content for dry fruit candy was maximal 25% (SII No.0718-2003) and maximally allowed ash content for food materials was 1.0% (SII 0272.90). Vitamin C content was not much decreased compared with ripe tomato, i.e. 30-40 mg/100. Organoleptic tets result indicated that A (40%) group get the highest score, i.e. 3,98 for taste, 3,89 for flavor, and 3,98 for color.