Consumers sensory evaluation of melon sweetness and quality

CONSUMERS SENSORY EVALUATION OF MELON SWEETNESS AND QUALITY Agulheiro Santos, A.C, Rato, A.E., Laranjo, M. and Gonçalves, C. Departamento de Fitotecnia, Escola de Ciências e Tecnologia, Instituto de Ciências Agrárias e Ambientais Mediterrânicas (ICAAM), Instituto de Investigação e Formação Avançada (IIFA), Universidade de Évora, Polo da Mitra, Ap.94, 7002-554 Évora, Portugal. ABSTRACT The sensory quality of fruits is made of a range of attributes like sweetness, acidity, aroma, firmness, color. Taste perception and perception threshold of these attributes are variable according to the psychological and cultural development of individuals. To better understand the quality evaluation of melon by consumers, consumers were invited to taste melon samples, in supermarkets in Évora (South region), Lisbon (Central region) and Vila Nova de Gaia (North region). The present work explored the importance given by consumers to sweetness in order to classify the overall quality of melon. Furthermore, the relationship of the chemical evaluation of Total Soluble Solids (TSS) with sweetness of melon was studied. Fruits from the variety Melão branco picked randomly from those that were exposed for sale in supermarkets were used for analysis. Fruits were chinned along the equatorial zone and only the central part of the fruit, opposite to the part that leaned on the soil, was used to obtain homogeneous samples. Consumers were invited to taste four small pieces of each fruit, previously referenced with a code number, and answer a questionnaire with two questions related to sweetness and overall quality. Each question had five possible levels, identified from “Nothing sweet”, to “Extremely sweet”, in one case, and from “Poor” to “Excellent” in the other. Simultaneously, the values of TSS (measured in ºBrix) for each melon used in the study were evaluated by refractometry. This sensory analysis allowed us to point out the following findings: first of all, there is good agreement between the results obtained to classify “Sweetness” and “Overall Quality” (Cohen’s Kappa=53.1%, p<0.001), which means, for example, that fruits with excellent quality are in general extremely sweet. Moreover, fruits with less than 9.6 °Brix are considered of poor quality and nothing sweet, whereas fruits with values between 10 °Brix and 12 °Brix are considered good in terms of overall quality. It seems that the thresholds for the stimulus/intensity of sweetness lied between 10 °Brix to 14 °Brix for this melon variety. Acknowledgments This work was support by national funds through Fundação para a Ciência e a Tecnologia (FCT) under the Strategic Project Pest-OE/AGR/UI0115/2014 and co-funded by FEDER funds through the COMPETE Program.

Influence of different land uses on groundwater quality in southern Portugal

In Alentejo region, southern Portugal, differences in groundwater samples from six groundwater bodies covered with different land uses were analysed based on the monitoring plan of the Alqueva multi-purpose project, created in the sequence of the construction of the Alqueva Dam on the Guadiana River, in South Portugal. For most of the groundwater bodies there is a statistical significant difference between magnesium, sulphate, chloride, and phosphate. All of these ions are strongly correlated with land use management. Groundwater, where land is covered by olive groves, has high levels of electric conductivity, calcium, potassium, sulphate, and phosphate. Dry land crops are correlated with calcium, magnesium, chloride and consequently, electric conductivity, phosphates and sulphate. Vineyards are strongly correlated with high sulphate and phosphate levels. This study clearly shows that different land uses within a certain groundwater body influence the water quality in a different way. Therefore, an appropriate soil management should be adjusted to each situation, taking into account the aquifer matrix and the overlying soil.

Tannins in Ruminant Nutrition: Impact on Animal Performance and Quality of Edible Products

Tannins are widespread throughout the plant kingdom, occurring as hydrolysable and condensed tannins and at different levels in several animal feeding sources. Recent years have seen an increasing interest in the use of tannin-rich plants and plant extracts in ruminant diets for improving the quality of their edible products. Some results show that this strategy is effective in improving the fatty acid profile of meat and milk, increasing the level of health-beneficial fatty acids as well as enhancing the oxidative stability of the products. However, the use of tannin-rich feed in animal diets requires great care, due to its possible detrimental effects on animal performance and induction of metabolic disorders. Although promising, the results of studies on the effects of tannins on animal performance and quality of their products are still controversial, probably depending on type and chemical structure of tannins, amount ingested, composition of diet, and species of animal. In this chapter, the current knowledge regarding the effect of dietary tannins on animal performance and the quality of their products (meat and milk), particularly on the fatty acid profile, oxidative stability, and organoleptic properties, is reviewed. The tannin chemistry diversity and its occurrence in ruminant diets, as well as its beneficial and adverse effects on ruminants, will be briefly reviewed, and aspects related to oral cavity physiology, saliva production/composition, and postingestive effects will also be discussed.