Composição química, cor e qualidade sensorial do tomate seco a diferentes temperaturas

Abstract

ResumoNeste trabalho foi avaliado o efeito da temperatura de secagem nos conteúdos de compostos fenólicos totais, licopeno e ácido ascórbico, na cor e na qualidade sensorial do tomate seco. Tomates cultivar Dominador foram secos a 55, 65, 75 e 85 ºC. A cor instrumental do tomate seco foi determinada separadamente nos lados da polpa e da casca. Na análise sensorial afetiva, foram analisados os atributos aparência, cor, aroma, sabor e textura. O índice de aceitabilidade e a intenção de compra também foram considerados. De acordo com os resultados, concentrações crescentes de compostos fenólicos totais e licopeno foram verificadas com o aumento da temperatura de secagem do tomate entre 55 e 75 ºC. Diminuição significativa no conteúdo de ácido ascórbico foi verificada durante a secagem, cujos valores variaram de 38,82 ± 2,47 mg 100 g -1 após secagem a 55 ºC, caindo para 21,68 ± 1,30 mg 100 g -1 a 85 ºC. Decréscimos significativos nos valores de a* e L* foram verificados em ambos os lados da fatia do tomate seco (polpa e da casca), mostrando que o aumento da temperatura causa perda de cor vermelha e escurecimento do tomate seco. De acordo com a análise sensorial, dentre as temperaturas testadas na secagem do tomate a que apresentou melhores resultados foi 75 ºC. Este estudo mostrou que a secagem convencional de tomate com ar aquecido a 75 ºC é a mais recomendada entre as temperaturas testadas. Palavras-chave: Lycopersicon esculentum, ácido ascórbico, fenólicos totais, licopeno AbstractThis study evaluated the effect of drying temperature on the total phenolic compounds, lycopene and ascorbic acid contents, color and sensory quality of dried tomato. Tomatoes cv. Dominador were dried at 55, 65, 75 and 85 °C. The instrumental color of dried tomato was determined separately on the sides of pulp and peel. In affective sensory analysis appearance, color, aroma, flavor and texture attributes were considered. Acceptance index and purchase intent were also evaluated. According to the results, increasing concentrations of phenolic compounds and lycopene were observed with increased drying temperature to 75 °C. Significant decrease in ascorbic acid content was observed during drying, which ranged from 38.82 ± 2.47 mg 100 g -1 after drying at 55 °C, dropping to 21.68 ± 1.30 mg 100 g -1 at 85 °C. Significant decrease in values of a* and L* were observed on both sides of the dried tomato slices (pulp and peel), showing that the increase in temperature causes loss of red color and browning of dried tomato. According to sensory analysis, among the temperatures tested in drying tomatoes the one that showed best results was 75 °C. This study showed that drying-conventional tomato with air heated to 75 °C is the most recommended among the temperatures tested.

Efeito da temperatura sobre a cinética de secagem e a cor do tomate italiano

“…Sacilik (2007) verified reduction in the values of L* and a* increasing the drying temperature from 50 to 60 °C for treated and non-treated samples, indicating that the tomato color is maintained only at low temperatures. Similarly Cruz;Braga;Grandi (2012) observed to increase in the darkening with to increase temperature of tomato drying.…”

“…The observed changes are due to hardening, movement of soluble solids and retraction (KROKIDA;PHILIPPOPOULOS, 2005). High temperatures or long drying times can cause serious damage to product flavor, color and nutrients, and reduce the rehydration capacity of the dried product (DOYMAZ, 2007;BARRERA;ANDRÉS, 2007;MURATORE et al, 2008;CRUZ;BRAGA;GRANDI, 2012). The damages are most common pigment degradation, especially carotenoids like lycopene (responsible for the red color in tomatoes) and chlorophyll, and browning reactions such as Maillard condensation of hexoses and amino components, and oxidation of ascorbic acid.…”

“…This fact, coupled with inadequate control of initial quality, incidence and severity of injury, exposure to improper temperature and delay between harvest and consumption, resulting in significant losses in quality of fruits such as tomatoes (RAUPP et al, 2009;EVRANUZ, 2011). Due to the great compatibility of the tomato with the dehydration process, this technique has been identified as one of the main alternatives to reduce losses and add value to raw material (JANGAM; MUJUMBAR; LAW, 2010;PURKAYASTHA et al, 2011), transforming it from a product often undervalued due to the excess supply in a differentiated product that targets a new market, winning consumers (SOUSA et al, 2010, SILVA et al, 2010CRUZ;BRAGA;GRANDI, 2012). Drying is the most common form of food to preserve and prolong the food self-life.…”

“…Other factors affecting color include fruit pH, acidity, processing temperature and duration, fruit cultivar and heavy metal contamination (MARFIL;SANTOS;TELIS, 2008;MURATORE et al, 2008). Consumer demand has increased for processed products that keep more of their sensory properties and their nutritional value, so that it has become necessary to optimize drying conditions in order to achieve certain characteristics related to colour, texture and water content (HEREDIA; BARREA; ANDRÉS, 2007;CRUZ;BRAGA;GRANDI, 2012).…”

Hybrid System Simulation to Supply Heated Air to a Solar Food Dryer

“…Engenharia Agrícola, Jaboticabal, v.40, n.2, p.154-161, mar./apr. 2020 The temperature used in the drying process of food products varies according to the type of product and, in some cases, for the same product different drying temperatures are used, as studied in Cruz et al (2012). The value for the target temperature, T set , of 70 o C was selected based on the following works available in specialized literature: Queiroz et al 2011, Corrêa et al (2015), Basso (2017), and Nunes et al (2017).…”