Variation in fruit chemical and mineral composition of Kenyan guava (Psidium guajava L.): Inferences from climatic conditions, and fruit morphological traits

There is limited knowledge about the impact of climatic conditions and fruit morphological traits on the nutritional composition of the guava fruit. Fruits were gathered from 128 guava trees across four geographically diverse regions of Kenya. The fruits were morphologically characterized and analysed for their chemical and mineral composition. The ascorbic acid content correlated positively only with total annual precipitation, while total soluble solids (TSS) correlated positively with mean annual temperature. TSS correlated negatively with pulp weight and was higher in white-fleshed fruits than in the red-fleshed types. The mineral content of the fruits correlated negatively with most of the fruit weight- and size-based morphologicaltraits, as well as with the total annual precipitation, but positively with fruit seed proportion. This information could act as a guide in the selection of specific regions for upscaling guava production and aid in the selection of accessions for improvement programmes that enhance guava fruit nutritional composition

Assessment of sensory profile and instrumental analyzed attributes influenced by different potassium fertilization levels in three tomato cultivars

Sensory properties are an essential quality aspect when the consumption of fresh tomato is under consideration. The flavor of tomato is defined as a combination of taste sensations (sweetness, sourness), aroma (volatile compounds), and texture (firmness, mealiness), some of which are proven to be affected by insufficient nutrient supply − especially potassium (K). This study intends to undertake a holistic assessment of the K fertilization effect on the flavor of tomato by connecting the use of sensorial and instrumental methods. An optimal K supply significantly increased the sensory descriptors sweetness, sourness, and aroma as well as the instrumental estimated color, firmness, total soluble solids (TSS), titratable acids (TA), and dry matter (DM) in a cultivar-specific manner. The volatile organic compounds (VOCs) were not significantly affected by K fertilization. The evaluation by the panelists confirmed the results of the instru-mental analyses, by which an increment in the fruit quality with rising K supply could be detected. An optimal K supply of 3.66 g/plant could be suggested to increase tomato flavor in the cocktail cultivars studied: Primavera and Yellow Submarine. Cultivar effects should, therefore, be considered for defining the optimal K fertilizer dose that favors high tomato fruit quality and, hence, better flavor

The Importance of Detailed Chemical Mechanisms in Gas Turbine Combustion Simulations

This paper – in memory of Jürgen Warnatz – summarizes selected recent papers of the Chemical Kinetics Group at the German Aerospace Center in Stuttgart. It shows the need for detailed chemical reaction mechanisms to understand practical combustion systems. A comprehensive description of combustion processes based on detailed mechanisms is especially important in the design of new gas turbine combustion chambers and in the optimization of existing ones to improve efficiency and to reduce pollutant emissions, with fuel-flexibility and load-flexibility ever becoming more important. Different aspects of combustion processes where detailed reaction mechanisms provide useful insights will be covered in this paper: Fuels (alternative jet fuels, biomass based fuels), pollutants (soot), diagnostics (chemiluminescence), and thermochemistry. Furthermore, the underlying thermodynamics inevitably connected with detailed reaction schemes will be addressed. Exemplified results will be presented clearly demonstrating the predictive capabilities of detailed reaction mechanisms to be explored in computational fluid dynamic simulations to further optimize technical combustion systems