Análise elementar de águas e sumos

A concentração de seis elementos: Cd, Cr, Pb, Ni, Zn e Fe foi medida em sessenta e sete amostras de sumos de fruta 100 %, duas amostras de refrigerantes, dez amostras de concentrados de sumos e sete amostras de águas de diluição utilizadas no processamento dos sumos. As amostras de sumos representam numa prespectiva bastante abrangente o mercado Português de sumos de fruta 100 %. Os refrigerantes concentrados e águas de diluição foram cedidos por duas empresas fabricantes de sumos Portuguesas. As concentrações elementares foram medidas pelas técnicas de FAAS e GFAAS e foi medido também o grau Brix dos sumos. Os factores: fruta, percentagem de fruta, origem, agricultura, tratamento, embalagem, conservação e processo foram obtidos por informação do fabricante nos rótulos dos produtos e por contacto directo. Caracterizou-se o mercado em termos da concentração desses elementos e caracterizou-se a sua diluição comparando-a com valores de referência do mercado Europeu. Mediu-se o grau de associação entre os diversos parâmetros e a concentração final elementar dos sumos e utilizou-se a análise de agrupamentos, a análise de correspondência múltipla e a análise factorial para reestruturar a matriz de dados. Dos resultados obtidos, os sumos de fruta apresentam a seguinte ordem de grandeza nas suas concentrações elementares: Cd

Composting of different agro-food wastes: Effects of the phenolic and lignocellulosic fractions on greenhouse gases emissions

Currently, society faces a number of challenges related to the large amounts of organic wastes generated and accumulated by the increasing expansion of agroindustrial activities1. Most of these wastes are rich in lignocellulosic compounds, which represents a major fraction of all plant biomass (of above 90%), so, its degradation is crucial for global carbon cycle2. These organic wastes may be introduced directly on agriculture sector as soil organic amendment, however, these might contain phytochemicals, such as phenolic compounds which may introduce toxic effects to soil and to beneficial organisms. Transformation and degradation of these renewable organic wastes into composts (COMPOSTING) is a possible solution for these problems and an environmentally friendly processes that allows make use of natural resources efficiently3. The main potential handicap is generation and emission of greenhouse gases such as carbon dioxide (CO2 ), methane (CH4 ) and nitrous oxide (N2O) and another ones which may led serious problems like nitric oxide (NO) and ammonia (NH3) 4. For this reason, quantification of GHG emissions from composting and finding possible relations with the chemical and structural composition of the wastes used is crucial to the development of technologies for mitigating emissions and should help to make decisions concerning waste management.

Chemical Composition and Bioactive Compounds in Bananas and Postharvest Alterations

Bananas arise as one of the most popular fruits consumed all around the world. Banana belongs to the genus Musa from the family Musaceae. It is original from tropical regions and presents a strong ability to protect itself from the oxidative stress caused by extreme climatic conditions such as intense sunshine and high temperature. For this protection, bananas increase the production of bioactive compounds with antioxidant activity, which protect the fruit from the oxidative damage. Scientific studies have demonstrated that bananas (both in the pulp and peel) contain different antioxidant compounds, like vitamins (A, B, C and E), β-carotene and phenolic compounds (catechin, epicatechin, lignin, tannins, anthocyanins). Furthermore, banana is also notably rich in minerals, like potassium and phosphorus. The knowledge about the chemical composition and the contents in compounds with biological activity is of high interest given the importance of bananas as a valuable food all over the world. However, because bananas are perishable due to some factors like chemical reactions, including those that result in the production of ethylene, their postharvest conservation in pivotal for the commercialization. The effects of postharvest treatments and storage conditions on the composition of bananas are, therefore, essential. In this way, the present chapter focus on the composition of bananas, including macronutrients, micronutrients and bioactive compounds, as well as the effect of postharvest treatments and storage conditions in the quality of bananas.