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Contém referências bibliográficas

Contém referências bibliográficas

Na obtenção de azeite, tão importante quanto a qualidade da matéria-prima, são os cuidados a ter na laboração. Só é possível produzir azeites virgens de elevada qualidade sensorial e nutricional, a partir de frutos de boas caraterísticas que garantam que os atributos positivos da azeitona sejam transferidos para o azeite. As boas práticas de higiene geral dos alimentos encontram-se enumeradas no Regulamento (CE) N.º 852/2004, nomeadamente no programa de pré-requisitos, no Anexo II, respeitante aos Requisitos Gerais de Higiene aplicáveis a todos os operadores do setor alimentar. Por outro lado, o azeite deve ser embalado em materiais aptos ao contacto com alimentos, conforme definido no Regulamento (CE) Nº 1935/2004, e respetivas alterações. As disposições específicas a aplicar a cada estabelecimento, devem ser avaliadas para resolver situações de riscos particulares, nomeadamente aplicando os princípios de um sistema de segurança alimentar (HACCP). No âmbito da classificação do azeite e da avaliação da sua componente analítica o regulamento de orientação é o Reg. (CEE) Nº 2568/81, e respetivas alterações referenciada pelo Regulamento de Execução (UE) Nº 1348/2013 de 16 de dezembro. O presente manual pretende orientar a produção de Azeites de Montanha de “excelência”. Além das questões de segurança alimentar que são de caráter obrigatório, dão-se, para cada etapa do processo, indicações para melhorar a qualidade do produto final. Assim, serão referidos os pontos-chave a considerar, desde a colheita da azeitona ao embalamento do azeite, para a obtenção de um produto seguro e com as caraterísticas sensoriais, químicas e nutricionais valorizadas.

During the ageing process of wine spirits several phenomena occur, which are responsible for the final quality of the beverage. This work aimed to discriminate the aged wine spirits according to the wood species, ageing technology and ageing time using FT-Raman methodology. For this purpose, the same Lourinhã wine distillate aged in 250-L wooden barrels of Limousin oak wood (L) and chestnut wood (C) separately and used together (L + C), was monitored through FT-Raman during the first 12 months of ageing. This technique was also applied to the same wine distillate aged in stainless steel tanks with staves of the same kinds of wood and during the same period. FT-Raman allows separating the wine spirits according to the different wood species and ageing time. This technique seems to be a promising tool to monitor the ageing process of wine spirit through different technologies.

Trabalho apresentado na 3rd Scientific Conference of Institute of Tropics and Subtropics, que decorreu em Novembro de 2009 em Praga.

In this study samples of the monofloral honeys more common in Castelo Branco region were tested: Eucalyptus ssp., Erica spp. and Lavandula spp. Evaluation of unifloral conformity was carried out by laboratorial pollen analysis.

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The aim of this work is develop a tool based on neural networks to predict the botanical origin of honeys using physical and chemical parameters. The managed database consists of 49 honey samples of 2 different classes: monofloral (almond, holm oak, sweet chestnut, eucalyptus, orange, rosemary, lavender, strawberry trees, thyme, heather, sunflower) and multifloral. The moisture content, electrical conductivity, water activity, ashes content, pH, free acidity, colorimetric coordinates in CIELAB space (L(∗), a(∗), b(∗)) and total phenols content of the honey samples were evaluated. Those properties were considered as input variables of the predictive model. The neural network is optimised through several tests with different numbers of neurons in the hidden layer and also with different input variables. The reduced error rates (5%) allow us to conclude that the botanical origin of honey can be reliably and quickly known from the colorimetric information and the electrical conductivity of honey.

The aim of this work is to evaluate the methodology to obtain an extract rich in caffeic acid (CAD) derivatives in spent coffee ground (SCG) and evaluate its free radical scavenging activity. Eighteen SCG samples and coffee beverage were collected from different brands and coffee shops. The SCG extracts were prepared by three methods: A) ethanol 96o according Campos et al [1]; B) extracts prepared in A were hydrolysed with HCl 37% (1:10), according Markham [2]; C) water extraction. All samples were screened by HPLC/DAD for phenolic profile characterization and structural identification and quantification of CAD [1]. Among caffeine the majority of the compounds found in the coffee beverage were CAD and in the SCG the compounds remaining the same. The hydrolysed extracts confirmed its existence, possible as glycosides (Fig. 1). The matrix resulting from the hydrolysis of the SCG can also be used to explore further bioactivities for therapeutic consideration once the released aglycones are in general more active. Method A was the most efficient (4.305 mg CAD/g SCG). Nevertheless the results were different according to the products. The caffeine ratio between SCG and expresso coffee was 17% and the ratio of CAD in both samples was 8%. A significant free radical scavenging potential (activity of DPPH) was founded yet in SCG (EC50 = 1.857 µg/mL) comparing with the coffee beverage (EC50 = 0.172 µg/mL) around 10% lower. The results show that the SCG has potential for future biological screening showing a stable compound profile and constitutes a much simpler matrix than the beverage, simplifying its analysis and further studies for potential bioactivities.

info:eu-repo/semantics/publishedVersion

The antioxidant activity of bee pollen (mainly composed by Cistus ladanifer pellets) was explored in the context of black pudding production. For this purpose, three black pudding formulations comprising varying antioxidant compounds (sodium ascorbate, bee pollen and bee pollen extract) were produced. Bee pollen was characterized according to the botanical origin, antioxidant activity, total phenol and flavonoid contents and phenolic profile. Black pudding was characterized by the microbiological safety, lipid oxidation, pH, water activity and humidity at 1, 10, 21, 30 and 37 days. Sensory acceptance was evaluated on the four first periods of storage. Salmonella spp., Escherichia coli and Listeria monocytogenes were absent in all samples. Small variations on humidity and pH were observed during the black pudding's storage. Regarding lipid oxidation, it increased, on average, from 1.36 mg to 2.11 mg malondialdehyde/kg meat. Differences among the three formulations were only significant on the first days of storage. The sensory assessment did not differ between products. This study suggests that bee pollen may be used as a natural antioxidant in meat products, yet a careful labelling is essential to alert allergic consumers.

The valorisation of agro-industrial by-products can be used as an alternative source for producing healthy food ingredients and materials. The volatile profile measured by headspace solid-phase microextraction-gas chromatography-mass spectrometry, mechanical, antioxidant and antibacterial properties of biodegradable cassava starch film extruded with the addition of different percentages of apple pomace (AP) by-product were evaluated. Characteristic volatile compounds were identified in the samples, such as α-farnesene, sulcatone and ethylphenyl propanoate. The film containing 8% AP had higher total phenolic content (3.32 mg GAE/g, Gallic acid equivalent) and antioxidant activity (2.78 mmol Trolox/g) than the control film (0.71 mg GAE/g and 1.03 mmol Trolox/g). The minimum inhibitory concentration against Staphylococcus aureus, Salmonella thyphimurium, and Escherichia coli for the films containing AP was higher than 12.5 mg/mL for all species. The results suggest that the antioxidant and antibacterial activities and mechanical properties, are dependent on the quantity of the AP added to films. Due to its antioxidant activity and mechanical properties, the AP could have real potential use as a functional ingredient in biodegradable packaging with the advantage of having good antibacterial properties.

Natural products are increasingly becoming part of our daily lives through their use in industry, food, as therapeutic agents, etc. To evaluate their possible applications, it is essential to characterize them chemically to explore their potential. Different techniques may be used to characterize natural products, including microextraction techniques. These techniques have been gaining popularity due to the advantages associated with their low use of organic solvents and the small amount of sample used relative to more classical sample preparation techniques. Their application in the extraction of compounds from natural products is still scarce. This manuscript intends to review the most used solid-based miniaturized sample preparation techniques applied to determining compounds in natural products. The main applications of these methodologies will be discussed, with a particular focus on natural product analysis, as well as their advantages and disadvantages over traditionally used sample preparation techniques.