Physical-chemical quality and nutritional composition of tomato (Solanum Lycopersicum) fruits as influenced by different factors during postharvest life

The concept of tomato quality refers to all attributes that consumer consciously or unconsciously believes that the fruit must have. However, it is necessary to expand this concept not only by consumer but also to all who participate in fresh tomato chain, from production to consumption. Producers must pick up fruits with high yielding, resistant to diseases, good and with few defects. Distributors intend to maintain sensory properties and to provide efficient storage, while consumers determine their quality by appearance, consistency, cross-sectional diameter, deformations and injuries absence. Physical-chemical attributes are used to assess quality in fresh tomatoes. Colour, firmness, flavour and nutrition value are important quality indicators. Colour is considered a major attribute of tomatoes and relates primarily to the lycopene content. Tomato colour should be uniform and textural quality of tomatoes is influenced by flesh firmness. Firmness changes are highly correlated with tomatoes surface appearance properties which are related to colour, shape and sense of firmness feel at the time of purchasing. Flavour is the function of taste and aroma components. The relationship between the acidity and soluble solids of tomato fruit is critical to its perceived flavour. Good aroma and taste are important factors that influence tomato commercialization. In recent years, consumers have complained about poor flavour in tomato. They consider the new long-shelf life cultivars less tasty than the traditional ones, and would pay higher prices for a product with better flavour quality. Tomatoes are a valuable source of several health-promoting compounds due to the balanced mixture of minerals, micronutrients and antioxidants, including vitamins C and E, carotenoids, potassium, folate, tocopherol, and flavonoids such as quercetin. Tomato fruits are well known for being an economical source of vitamins, with high vitamin C content and also significant amounts of vitamin A and B. It also contains a large amount of water and minerals, such as potassium, magnesium, phosphorous and calcium, with great importance in human metabolic activities. In addition to these well-known phytonutrients, other compounds in tomato fruit with antioxidant properties include chlorogenic acid, rutin, plastoquinones, tocopherol, and xanthophylls. Most of these nutrients in tomatoes confer a preventive benefit against oxidative stress-associated diseases, through various mechanisms, including antioxidant action. Postharvest period begins at the separation of plant used as food from the medium of its immediate growth or production, and ends when it enters the preparation process for final consumption or further preservation. Quality deterioration of harvested fruits is the result of a combination of physiological, mechanical, microbiological and environmental factors and conditions. In view of the important role that the tomato plays in the human diet, the quality and nutritional composition of tomato fruit and important aspects that influence its quality are discussed in this chapter.