Long life tomato (Solanum Lycopersicum): price is quality?

1 Scientific Electronic Archives Issue ID: Sci. Elec. Arch. Vol. 12 (5) October 2019 DOI: http://dx.doi.org/10.36560/1252019796 Article link http://www.seasinop.com.br/revista/index.php?journal=SEA&page=arti cle&op=view&path%5B%5D=796&path%5B%5D=pdf Included in DOAJ, AGRIS, Latindex, Journal TOCs, CORE, Discoursio Open Science, Science Gate, GFAR, CIARDRING, Academic Journals Database and NTHRYS Technologies, Portal de Periódicos CAPES.


Introduction
The commercialization of tomatoes (Solanum lycopersicum L.) has high economic relevance, being among the most cultivated vegetables in the world (FAO, 2018). In Brazil the large volume is traded in the forty-one Supply Centers (CEASA) spread throughout Brazil, being sold in 2016, in Goiás Supply Center (CEASA-GO) 105.7 thousand tons, representing 11.26% of the total of vegetables sold (IBGE, 2018). It is observed that there is an increasing demand for a healthy diet, opting for fresh fruits and vegetables, and its decision-making guided by the price and quality parameters (Teixeira et al., 2006;Ribeiro et al., 2017). Tomato quality is associated with physical characteristics such as size, texture and color that will determine consumer acceptance of the product (Borguini and Silva, 2009;Andreuccetti et al., 2005), as well as its marketing price.
Selling value and quality are parameters influenced by cultivation conditions, climate, transportation, distribution and storage, and when mishandled promote physical damage and injury, leading to qualitative and quantitative losses to the tomato chain (Cantwell et al., 2009;Oliveira et al., 2013). In this reasoning, it becomes possible to interpret the price differences found in the two distinct commercialization places commonly within the CEASAs, "Boxes" and "Pedras". "Boxes" are entrepreneurial-controlled bulk storage, distribution and marketing centers that buy and resell vegetables, often seen as better quality products. The "Pedras" are areas without fixed structure, intended for the rural producer himself to market his products, being seen as lower quality products (Goiás, 2009).
The fruits sold in the "Boxes" are usually of better quality due to the preservation postharvest technologies used (postharvest uniformity, refrigerated storage), which would justify the higher price compared to tomatoes sold in the "Pedras". As there is a scarcity of work on this subject, the present work aimed to evaluate the quality of fruits marketed in CEASAs in different places, as well as to demystify if there are differences in the quality of table tomatoes marketed, since there is a price difference applied between the marketing places.

Plant material
Type 2 long-life tomatoes (60 to 75 mm in diameter) were collected monthly from February to August 2017, with the criterion of choosing the day and place of sale according to the days of highest fruit volume in CEASA-GO (Latitude 16 ° 37´S and Longitude 49 ° 12´). Forty-four pounds were sampled from each marketing place ("Pedras" and "Boxes") by date. At the time of collection, the origin of the fruit and the commercialization value were noted. It should be noted that the value was measured by basic tomato sales unit in the CEASAs, which are boxes of 22 kg. Thus, the average value was expressed in R$/22 kg of tomato.

Quality reviews
The tomatoes were packed in plastic bags and immediately transported to the Postharvest Laboratory of Vegetables of the Federal University of Goiás (UFG), located at the College of Agronomy. In the laboratory they were randomly separated into nine replicates, with three fruits and the analyzes performed in triplicate.

Statistical analysis
The experiment was conducted in a completely randomized design, in a 2 x 7 factorial scheme (2 sites x 7 collection periods). Data were submitted to analysis of variance (ANOVA) and means test between sampling sites and collection period (Tukey at 5% probability level). The Sisvar version 5.6 software was used for data analysis (Ferreira, 2014).

Results and discussion
Most of the tomatoes sold came from the state of Goiás (78.57%), and the rest came from the states of Santa Catarina (10.72%), Distrito Federal, São Paulo and Minas Gerais (3.57% each). The average price of the basic marketing unit (22 kg of tomatoes) was R$ 29.82, and the price practiced on the "Pedra" (R$ 27.50) is lower than the "Boxe" (R$ 32.14), as shown in Table 1. In the off-season months (February to May), which in the state of Goiás is marked by the rainy season, where a large volume of rainfall occurs, impairs the production and quality of fruits (Brasil, 2012). In this period there was the initiative of entrepreneurs ("Boxes") to seek tomatoes from other sources, which highlights the importance of this place of marketing for the constant supply of food. CEASA-GO's marketing calendar (2018) showed that the months with the highest tomato offerings were from July to October. During this period, the lowest commercialization values are expected. Machado et al. (2008) corroborated that variations in tomato prices are greatly influenced by harvest / off-season periods. However, the average price of tomatoes during the off-season was R$ 32.00, while between July to August was R $ 35.00, which cannot be justified by the offer of the product (Table 1). Another possibility was that the fruits of "Boxes" presented higher prices due to the supposed better quality and that added the value of transportation, selection, among others. Regarding quality, one of the first items observed by the buyer is appearance, that is, coloration that can be objectively expressed by the brightness variables, a * and b *. The parameters luminosity and a * did not differ in relation to the place of sale, presenting difference only in relation to the period of sale. The fruits collected in March, April, May, July and August presented higher brightness and lower color parameter a * (Figure 1a and 1b, respectively).
While the b * parameter had difference with the place and collection period ( Figure 1C).
The relation a * / b * allows to identify the predominance of red color and green color in tomatoes, and values > 0 indicate the predominance of red color and < 0 the predominance of green color. Thus, figures 1B and 1C showed that most of the fruits collected had a color closest to green. The luminosity is related to the intensity of the color, darker fruits have a lower luminosity value. Thus, redder and opaque fruits will have a lower luminosity (Arias et al., 2000). Different letters represent significant difference by Tukey's t-test (p <0.05). Uppercase letters when comparing the locations ("Boxes" and "Pedras") and lowercase letters when comparing the months of fruit collection. Vertical bars represent the standard deviation of the mean.
Another noticeable parameter that influences at the time of purchase is firmness. In tomatoes, there was no difference in relation to the collection sites. However, there was a difference in relation to the collection period (p <0.05), with the highest values of March, May, July and August (Figure 2). Chitarra & Chitarra (2005) reported that firmness in fruits is susceptible to changes according to production and marketing times, directly affecting product quality.
There were no differences in color and firmness between the fruits sold in the "Boxes" and "Pedras" justifying the difference in prices. The soluble solids content was higher in the fruits obtained in the "Boxes" between March, May, July and August ( Figure 3A), but the acidity did not differ according to the collection sites, with February being the lowest value. (Figure 3B). Soluble solids and titratable acidity influence the taste and aroma of fruits, affecting the quality and consumer acceptance of the product (Rosales et al., 2011). This is because, the greater the relationship between soluble solids content and titratable acidity, the sweeter the fruit (Borguini & Silva, 2009;Rosales & Cervilla, 2011). Given the results obtained, it can be stated that the differences found in quality are not related to the place of sale, but rather to the time of production.
Vitamin C levels were similar at the marketing sites, with values ranging from 20.41 to 31.12 mg% ( Figure 3C). However, the fruits collected in "Pedras" in March had more vitamin C than those sold in Boxes. These results may have been influenced due to the different storage conditions (refrigerated or not), which results in a greater loss of water during this month, added to the high temperatures found in this period of the year.
The vitamin C content is an important parameter of tomato nutritional quality, which according to the Brazilian Table of Food Composition (Nepa, 2011), the average content is 21 mg / 100 g, lower than the one found ( Figure 3C). Vitamin C content may be related to the quality of production of a vegetable since the climate, cultivation practices and post-harvest handling are related to this content (Lee & Kader, 2000;Chitarra & Chitarra, 2005).