Critical points of industrial tomato from field to processing

The authors evaluated critical points of production stages of the industrial tomato, through physical and physico-chemical analyzes of U2006 hybrid fruits in the harvest, 2016. Fruits were evaluated in relation to raw material, temperature, fresh mass, pH, soluble solids (°Brix), firmness, titratable acidity and extravasation of electrolytes. Samples were collected in six steps: manual, mechanized, truck, arrival at industry, unloading and selection mat in two periods, morning and afternoon, totalizing 60 fruits for each step, and four replications. Fruits which waited for more than 10 hours in the yard generated an increase in serious defects (%), loss of fresh mass, discount on the amount paid for the load. The most critical stages of the production process were identified when tomatoes arrived at the industry and their unloading, when the fruits presented fresh mass loss due to the high temperature. In addition, the authors highlight that a better organization in the arrivals at the industry as well as an efficient communication of crop restriction is crucial, since unscheduled stops increase waiting time, causing significant quality losses.


Scientific communication
Hortic.bras., Brasília, v.36, n.4,October-December 2018 T omato is the second most grown vegetable consumed worldwide.This plant is a crop of great economic and social importance being also important in human diet.Goiás (86%) followed by São Paulo (12.7%) and Minas Gerais (1.3%) are the main states where tomatoes are produced for processing industries (Vilela et al., 2012).
This study was carried out in the municipality of Morrinhos, Goiás State, where industrial tomato cultivation stands out, productivity of 112 thousand tons (IBGE, 2015).
Water content ranges from 90 to 95%, which characterizes tomato as a highly perishable fruit, with losses of up to 21% after harvest (Rocha et al., 2009;Rinaldi et al., 2011).According to Mendes et al. (2011), an increase in breathing occurs due to the production of ethylene and other biochemical reactions responsible for changes in color, texture and nutritional quality after physical damage during harvest or shipping.
Therefore, tomato maturation during harvest and pre and post harvest control are essential in order to ensure fruit quality (Beckles, 2012), preventing the entry of pathogenic microorganisms (Ronchi et al., 2010).Physical damage significantly affects chemical and physical compositions of pericarp and locular tissue in tomato fruits (Ferreira et al., 2009).Thus, harvest done during the appropriate maturation stage will determine fruit quality (Damatto Junior et al., 2010).
We aimed to highlight the critical points from harvest to the processing of tomato fruits, being verified through physical and physico-chemical analyzes in the fruits.
Received on October 26, 2017; accepted on August 13, 2018 distinct periods of the day, morning and afternoon, to observe physiological changes caused by thermal stress.
The steps were: 1) Manual harvest (in the same area, right before mechanized harvest); 2) Mechanized harvest (sample collected on selection mat, when tomatoes were harvested); 3) Samples in the truck (collected in the truck still in the field); 4) Arrival at industry (samples collected at the moment when the truck arrived at the industry); 5) Unloading (samples collected when the tomato was unloaded for processing); 6) Selection mat (samples collected on the mat, in the industry).All used samples were obtained from the same truck in all steps.
Collecting phase totalized 60 fruits per each step.Fruits were packed in plastic boxes, in four replications.After collecting, samples were taken to the laboratory in boxes, which were stored at a climate-controlled room, for up to 12 hours, at 20°C temperature.
T h e a u t h o r s e v a l u a t e d t h e commercial tomato hybrid U2006 for industrial processing (Nunhems Brasil-Bayer Crop Science), resistant to diseases like bacterial spot and begomovirose, considered the main phytosanitary issues of tomato for industrial processing (Villas-Bôas et al., 2007;Fernandes, 2008).
Fruits were collected in two properties, in the beginning of harvest, 2016.The first property where the samples were collected, named "Property A", is located 12 km away from the industry, being 10 km asphalt road and 2 km dirt road.The second property, named "Property B", located 11.2 km away from the industry, being 10.9 km asphalt road and 0.30 km dirt road.
Raw material was classified at the industry, in order to evaluate defects in fruits, which interfere with the quality required for cargo pricing.All trucks were accompanied from the field up to processing and they were classified and analyzed using industry methodologies in six defects, being four defects classified as serious defects (disintegrated, visible locules, moldy and green) and two general defects (discolored and smashed).Obtained data were recorded on the form of quality control of goods receipt.According to Table 1, adapted from ordinance n° 278, 1988, MAPA.A discount was applied on cargo weight for payment purposes.
Analyses were done at Laboratório do Instituto Federal Goiano, Campus Morrinhos, for fresh mass, pH, soluble solids, firmness, titratable acidity and extravasation of electrolytes.
Data on average temperature and relative humidity were collected on harvest days of samples in the weather station of Instituto Federal Goiano Campus Morrinhos (17°48'50"S, 49°12'16" W, altitude 902 m) Fresh mass was measured on 30 fruits, randomly separated and put on plastic trays, being weighed in a semi-analytical balance (FCB 3K0.1, Kern, Kern & Sohn Gmbh, Stuttgart, Germany).
Titratable acidity was determined using the official method described by Instituto Adolfo Lutz, based on neutralization titration with NaOH (0.1 N) up to pH 8.2.Fruits were washed and dried with paper towels, before extraction of juice from 5 fruits per replicate using a fruit centrifuge (FastFruitInox, Suggar).Then, 1 mL of juice was transferred to an Erlenmeyer flask containing 9 mL distilled water and 3 to 5 drops of phenolphthalein indicator.Afterwards, titration was done with NaOH solution in six collect steps, in four replicates.
Acidity (in molar solution, % v/m) was calculated according to the following formula (Instituto Adolfo Lutz, 2008): Where V= volume in mL of NaOH solution (0.1 N) spent via titration; f= factor of NaOH (0.1 N); P= mass (g) of the sample used in titration; c= correction factor used was 10, since titration was done with NaOH (0.1N).
Firmness analysis was determined using flattening technique, 0.264 kg, with the aid of a caliper (1.0004, ZAAS), measuring length and diameter (in mm) on both sides of the fruit, in five fruits and six collect steps, with four replicates.The flattened area was estimated using the ellipse area formula (A) (Calbo & Nery, 1995): In which, to convert mm to cm, the authors divided mm by 10.
Firmness was obtained by dividing the weight of the probe (P) kilogram force by flattened area (A) cm 2 , Fz= P/A.(Calbo & Nery, 1995).
In order to convert fimness from Kgf to N, the equation was multiplied by 9.8.
To determine soluble solids, we calibrated the refractometer with distilled water having a zero-index of refraction.Juice was extracted from five fruits, using replication method, adding two drops of juice on the prism of the portable refractometer 0-32°Brix (RZT, Bel Engineering, Bel Equipamentos Analíticos LTDA) and then refractive index reading was carried out.After each reading, prism was properly washed with distilled water and dried with double-sided absorbent paper, until having all readings totaled (six collecting steps), performing four replicates and recording all obtained data, according to the methodology proposed by Instituto Adolfo Lutz.
To determine pH, fruits were washed and, right after, dried using a towel paper, then juice was extracted from 5 fruits of each replicate in the centrifuge (FastFruitInox, Suggar).Afterwards, they were measured using a pH meter (mPA-210, MS Tecnopon, MS Tecnopon Instrumentação) with standard solutions 4.00 and 7.00.After measurement, electrode was cleaned with distilled water and dried with double-sided absorbent paper.Thereafter, the authors performed the reading of the six-stepcollection samples with four replicates, recorded the obtained data, according to the methodology proposed by Instituto Adolfo Lutz.
Membrane electrolyte extravasation was evaluated according to some adaptations from the methodology described by Vasquez-Tello et al.
(1990) and Pimentel et al. (2002).Disks in 10 fruits, 5 mm diameter, of each replicate, were collected.The disks were washed previously in water and then submerged in 30 mL distilled water, in amber bottles, for 24 hours, at room temperature.Then, free conductivity was measured (CL, µS/cm), using a benchtop conductivity meter (EC-125, HANNA, Hanna Instruments, Padova, Itália).Afterwards, the same bottles were placed in an oven (Q317M, Quimis, Quimis Aparelhos Científicos, São Roque, São Paulo) for one hour at 100°C and after cooling at room temperature, and total conductivity was measured (CT, µS/cm).In order to avoid errors, the sensor was cleaned between each reading with distilled water.The electrolyte extravasation rate was obtained using the formula: The obtained data were submitted to ANOVA test for variance analysis and the averages were submitted to Tukey test, at 5% significance level.

RESULTS AND DISCUSSION
The morning shift waiting times were shorter, in relation to the afternoon shift, due to arrival order and process in industry.
Thus, over 10 hours of standby time, incidence of serious defects were greater than 20% (Table 2), resulting in a discount which reflected directly on the amount of money paid for the cargo, besides impacting on fruit quality.For producer and for industry, these factors are prejudicial since fruit was weighed after the waiting time in the outside area.
In Brazil, besides high luminosity, the temperatures are excellent for growing tomato, ranging from 21-28°C during the day and 15-20°C during the night (Filgueira, 2008).Average temperatures found are within the tolerance range in the morning, but not in the afternoon.Temperature in properties A and B (Table 2) showed significant differences during this period.The authors noticed some changes in the morning shift, in both properties where the weather was warmer due to the sunset and cooler during unloading due to the cold water used in this process.In the afternoon, the temperature in the field is very high and tends to decrease along harvest steps, until unloading and milling, due to the use of cold water in the last steps.
Property A did not show any significant difference in the morning (2,267 kg) and in the afternoon (2,167 kg) for fresh mass.On the other hand, property B showed significant difference both in the morning (2,389 kg) and in the afternoon (2,178 kg).The critical point was in unloading step in property A, whereas in property B, the highest loss of fresh mass was verified in the afternoon.Titratable acidity at high temperature did not increase the consumption of reserves and the activation of organic acids both in the morning and afternoon shifts (Table 2).
For firmness, in properties A and B no significant differences were verified during the steps.
In property A, in the morning, average °Bríx was 4.19 and 4.06 in the afternoon.Thus, no significant differences were noticed.In property B, average °Bríx was 4.40 in the morning and 4.14 in the afternoon.
In property A in the afternoon and B in the morning, the authors verified an increase in SST.According to Echeverria & Ismail (1990), an increase in SST is noticed after harvest.It may happen due to conversion of organic acids to intermediate glycolytics and subsequent to hexoses or the release of soluble sugars by other glycolytics such as starch hydrolysis, being the results of biological activities.
For pH, property A (Table 2) showed significant differences, whereas no significant differences were noticed in property B (Table 2).Properties A and B (Table 3) did not show any statistically significant oscillations.
Extravasation of electrolytes in properties A and B (Table 2) is higher in the afternoon.High temperatures changed the composition and structure of membranes, resulting in release of electrolytes (Kerbauy, 2012), leading to a loss of fresh matter and water.In property A, in the morning, the authors observed some changes within the steps with higher releases of electrolytes in the beginning of manual step and in the last step on the mat obtaining an atypical result.Properties A, in the afternoon, and B, in the morning and in the afternoon, showed no significant differences, using Tukey test at 5%.
Given the above, an increase in serious defects was observed over 10 hours of standby time, in the outside area.This fact resulted in a discount on the amount paid for the cargo, and also a higher loss in fresh mass.High temperature caused changes in composition and structures of membranes, and also releases of electrolytes, mainly in the afternoon shift.
The most critical points were arrival at industry and unloading, in which losses of water as well as fresh mass were clearly observed, due to high temperature and for being longer time in the sun and pressed in the container during the waiting time.
The authors suggest better logistics related to arrivals and communication when restricting crops due to unscheduled stops in the industry which increase waiting time.
Averages followed by same letters in the column do not differ from each other, Tukey test, 5% significance.