Bolivian tomatoes : genetic diversity, quality traits and value chains

Bolivia is considered one of the centres of origin and distribution of tomatoes, and wild relatives harbouring potential genetic diversity and quality traits are preserved in germplasm collections. Tomato is the most commonly grown vegetable world-wide, but in Bolivia, tomatoes are lowyielding and have short shelf-life. This thesis studied genetic diversity of 20 accessions and eight cultivars using 11 simple sequence repeat markers, quality traits and bioactive compounds in fruits of 29 accessions and eight cultivars using HPLC techniques. Fruit quality along the tomato value chain (TVC) was assessed in case studies in four provinces. Genetic diversity was found to be low and party influenced by plant growth type, geographical origin, fruit shape and size, and stage of maturity. A UPGMA tree distributed the 28 accessions into six groups, with separation between indeterminate and determinate plant growth type. Quality traits and polyamines (putrescine, spermidine, spermine) concentrations showed inconsistent variations between six maturity stages studied. At maturity, only two the 29 Bolivian accessions showed significant differences in polyamines concentrations. However, the accessions differed significantly in carotenoids and vitamin C content, but no interaction between polyamines and carotenoids concentrations was observed. Five critical factors within the Bolivian TVC were identified as affecting tomato quality: i) landscape and land access; ii) cultural practices; iii) harvesting process; iv) packing process; and v) transportation system. The new information on Bolivian genetic resources, bioactive compounds and desirable traits presented in this thesis can be used by breeders to develop new cultivars. In a broader perspective, the thesis identified constraints and actors involved in tomato quality determination in a developing country

Managing the Product Quality of Vegetable Crops under Abiotic Stress

Vegetables are an important part of the human diet due to their nutrient density and, at the same time, low calorie content. Producers of vegetable crops mainly aim at achieving high yields with good external quality. However, there is an increasing demand of consumers for vegetables that provide good sensory properties and are rich in secondary compounds that can be valuable for human health. Sub- or supra-optimal abiotic conditions, like high temperatures, drought, excess light, salinity or nutrient deficiency, may alter the composition of vegetable crops and at the same time, result in yield loss. Thus, producers need to adapt their horticultural practices such as through the choice of variety, irrigation regime, light management, fruit thinning, or fertilizer application to improve the yield and quality of the vegetable product. In the future, altered climate conditions such as elevated atmospheric CO2 concentrations, rising temperatures, or altered precipitation patterns may become additional challenges for producers of vegetable crops, especially those that cultivate in the open field. This raises the need for optimized horticultural practices in order to minimize abiotic stresses. As well, specific storage conditions can have large impacts on the quality of vegetables. This Special Issue compiles research that deals with the optimization of vegetable product quality (e.g. sensory aspects, composition) under sub- or supra-optimal abiotic conditions

Detecting and Monitoring the Flavor of Tomato (Solanum lycopersicum) under the Impact of Postharvest Handlings by Physicochemical Parameters and Electronic Nose

The objective of this study was to detect and monitor the flavor of tomatoes, as impacted by different postharvest handlings, including chilling storage (CS) and blanching treatment (BT). CS tomatoes were stored in a refrigerator at 5 °C and tested at storage day 0, 3, and 7. BT tomatoes were dipped in 50 or 100 °C water for 1 min, and tested immediately. The taste, mouth feel, and aroma of tomatoes were evaluated by testing the total soluble solid content (TSS), titratable acidity (TA), ratio of TSS and TA (TSS/TA), firmness, and electronic nose (E-nose) response to tomatoes. The experimental results showed that the CS can prevent taste and firmness loss to a certain extent, but the sensory results indicated that CS accelerated flavor loss due to the TSS/TA of CS tomatoes increasing slower than control. The taste and firmness of tomatoes were impacted slightly by 50 °C BT, and were significantly impacted by 100 °C BT. Based on physicochemical parameters, different postharvest handling treatments for tomatoes could not be classified except for the 100 °C BT treated tomatoes, which were significantly impacted in terms of taste and mouth feel. The E-nose is an efficient way to detect differences in postharvest handling treatments for tomatoes, and indicated significant aroma changes for CS and BT treated tomato fruit. The classification of tomatoes after different postharvest handling treatments, based on comprehensive flavor (physicochemical parameters and E-nose combined data), is better than that based on single physicochemical parameters or E-nose, and the comprehensive flavor of 100 °C BT tomatoes changed the most. Even so, the tomato flavor change during postharvest handlings is suggested to be detected and monitored by single E-nose data. The E-nose has also been proved as a feasible way to predict the TSS and firmness of tomato fruit rather than TA or TSS/TA, during the postharvest handing process

Detecting and Monitoring the Flavor of Tomato (Solanum lycopersicum) under the Impact of Postharvest Handlings by Physicochemical Parameters and Electronic Nose

The objective of this study was to detect and monitor the flavor of tomatoes, as impacted by different postharvest handlings, including chilling storage (CS) and blanching treatment (BT). CS tomatoes were stored in a refrigerator at 5 °C and tested at storage day 0, 3, and 7. BT tomatoes were dipped in 50 or 100 °C water for 1 min, and tested immediately. The taste, mouth feel, and aroma of tomatoes were evaluated by testing the total soluble solid content (TSS), titratable acidity (TA), ratio of TSS and TA (TSS/TA), firmness, and electronic nose (E-nose) response to tomatoes. The experimental results showed that the CS can prevent taste and firmness loss to a certain extent, but the sensory results indicated that CS accelerated flavor loss due to the TSS/TA of CS tomatoes increasing slower than control. The taste and firmness of tomatoes were impacted slightly by 50 °C BT, and were significantly impacted by 100 °C BT. Based on physicochemical parameters, different postharvest handling treatments for tomatoes could not be classified except for the 100 °C BT treated tomatoes, which were significantly impacted in terms of taste and mouth feel. The E-nose is an efficient way to detect differences in postharvest handling treatments for tomatoes, and indicated significant aroma changes for CS and BT treated tomato fruit. The classification of tomatoes after different postharvest handling treatments, based on comprehensive flavor (physicochemical parameters and E-nose combined data), is better than that based on single physicochemical parameters or E-nose, and the comprehensive flavor of 100 °C BT tomatoes changed the most. Even so, the tomato flavor change during postharvest handlings is suggested to be detected and monitored by single E-nose data. The E-nose has also been proved as a feasible way to predict the TSS and firmness of tomato fruit rather than TA or TSS/TA, during the postharvest handing process