Ana C. Pereira

University of Coimbra | UC · Department of Chemical Engineering

Cortisol monitoring in the agri-food sector is considered a valuable tool due to its direct correlation with growth, reproduction, the immune system, and overall animal welfare. Strategies to monitor this stress hormone and its correlation to food quality and security have been studied in fish farming and the livestock industry. This review discuss...

The globalisation of the beer market forces brewers to have methodologies that rapidly evaluate the evolution of beer flavour stability. Commonly used forced ageing methods have limitations since temperature and transportation conditions (temperature, vibrations, long-distance travel, and other factors) impact beer quality. This study assessed the...

Flavour stability is probably the most critical quality challenge brewers currently face, a concern transverse to all beer styles. Beer flavour starts to deteriorate almost immediately after production ends. Strategies to ensure and extend the beer shelf-life has mainly been studied, namely, the impact of the production process and raw material, th...

Madeira wine (MW) encompasses an unusual oxidative ageing process that makes it distinctive. Several metabolites have been related to its quality and safety, such as 5-hydroxymethylfurfural (HMF), furfural, sotolon, and ethyl carbamate (EC). These compounds were quantified over a three-year period to assess their formation rate according to the age...

Beer flavor stability is greatly influenced by external temperature, vibrations, and longer delivery times. The present study assessed the impact of transport and storage conditions on staling aldehyde evolution in lager beers across five sample groups (fresh, transport, and storage simulation, and their controls), which differed in their bottle op...

The unique agricultural rum produced in Europe, Agricultural Rum of Madeira, is obtained from alcoholic fermentation and distillation of sugarcane juice, followed by cask ageing for a minimum of 3 years. For the first time, the impact of underwater bottle ageing on the maturation of this type of spirit was studied. Herein, the physicochemical prope...

Despite the literature comprises numerous studies dealing with the analysis of wort and beer flavour-related compounds by HS-SPME followed by GC-MS quantification, no generalized consensus exists regarding the optimal conditions for the extraction procedure. The complex chemistry nature of these matrices, the number of analytes, as well as the numb...

Fucoxanthin is considered an important marine bioactive compound with biological properties with promising effects, namely on health. A simple and efficient analytical methodology is proposed for its quantification in seaweed biomass by using vortex-assisted solid-liquid microextraction (VASLME) followed by reversed phase high-performance liquid ch...

The world’s best-known fortified wines are Sherry, Port, Madeira, and Marsala. Others are Moscatel de Setúbal, Vermouth, and Commandaria. They have in common a high alcohol content [15%–22% alcohol by volume (ABV)] due to the addition of vinous alcohol or grape spirit during the winemaking process, after being fermented or partly fermented, produci...

Sotolon (4,5-dimethyl-3-hydroxy-2,5-dihydrofuran-2-one) is a powerful odorant usually pointed out as being responsible not only for the characteristic curry notes of the finest fortified wines but also for the off-flavour notes in prematurely oxidized white wines. Most methods reported in literature for quantifying sotolon in wines are quite labori...

The optimized operation of modern analytical instrumentation is a critical but complex task. It involves the simultaneous consideration of a large number of factors, both qualitative and quantitative, where multiple responses should be quantified and several goals need to be adequately pondered, such as global quantification performance, selectivit...

Sotolon and the heterocyclic acetals of glycerol are known as potential aging and oxidation markers in fortified wines such as Madeira, Port, and Sherry. Thus, determining the evolution of these compounds under different oxidative aging conditions is important for fortified wine quality purposes. This study proposes a new methodology based on a min...

In the present study, we apply the recently proposed Definitive Screening Designs (DSD) to optimize HS-SPME extraction in order to analyze volatile fatty acids (VFA) present in wine samples. This is the first attempt to apply this new class of designs to one of the most well-known and widely applied extraction techniques. The latent structure of th...

This work presents the optimization of a miniaturized liquid-liquid extraction (mLLE) followed by reversed-phase liquid chromatography-electrospray tandem mass spectrometry (RP-HPLC-MS/MS) for the determination of ethyl carbamate (EC) in fortified wine, without using derivatizing agents. The mLLE was optimized by an experimental design. Thus, 15 mL...

Solid-phase microextraction (SPME) is prevalent in most experimental procedures carried out to analyze volatile compounds in alcoholic beverages. Its benefits have been thoroughly discussed elsewhere and it is now being widely used in the analysis of a vast range of analytes and/or target chemical families. The present chapter aims to review the ap...

Blueberries have a well-deserved reputation as a potential functional food, supported by studies which have identified and quantified various nutrients and bioactive phytochemicals with known benefits for human diet and health. Wild blueberries have attracted particular attention due to the levels and concentrations of those phytonutrients. This st...

In this article, we extend the scope of the first paper of the sequel, which was dedicated to the analysis of advanced single-block regression methods [1], to the class of multiblock regression approaches. The datasets contemplated for developing the multiblock approaches are the same as in the former publication: volatile, polyphenols, organic aci...

In this paper we test and compare advanced predictive approaches for estimating wine age in the context of the production of a high quality fortified wine – Madeira Wine. We consider four different data sets, namely, volatile, polyphenols, organic acids and the UV-Vis spectra. Each one of these data sets contain chemical information of a different...

Regression methods are pervasive in most data-driven predictive studies performed with industrial and laboratorial data. They provide the means to obtain reliable estimates of output variables (related to product quality or other properties) based on a set predictor variables which are usually easier to measure and less expensive. In this paper, a...

The present study aims to analyse the evolution of colour and browning of fortified wines submitted to oak and accelerated ageing induced by temperature, both traditional ageing processes of Madeira wines. These wines were followed during the first 2 years of ageing and were simultaneously compared to aged reference samples, in order to disclose if...

Vicinal diketones, namely diacetyl (DC) and pentanedione (PN), are compounds naturally found in beer that play a key role in the definition of its aroma. In lager beer, they are responsible for off-flavors (buttery flavor) and therefore their presence and quantification is of paramount importance to beer producers. Aiming at developing an accurate...

The current study was focused on the impact of accelerated ageing (heating step) on the amino acid and biogenic amine profiles of fortified wines. In this sense, three Madeira wines from two commonly used grape varieties (one red and the other white) were analysed during the heating, at standard (45°C, 3 months) and overheating (70°C, 1 month) cond...

Aggregation of particles is fundamental for improving the performance of many solid/liquid processes. Aggregation can be induced by different means, and one of the most common is based on the addition of polymeric additives, namely polyelectrolytes. In this work we have studied the flocculation of precipitated calcium carbonate (PCC), which is used...

A systematization of complex data structures, originated in current processes and product analysis activities, is presented as a starting point for developing generalized and flexible frameworks for handling such challenging information sources. In this article, we present an abstract and unifying definition for a class of multidimensional data arr...

Wine age prediction based on its intrinsic characteristics can provide significant assistance to oenologists' quality evaluations, concerning wine ageing process control and wine quality assurance. Simpler, faster, cheaper and affordable analytical procedures would be greatly welcome to establish such a practice. In this study, we present a new and...

The present work aims to analyze the feasibility of different analytical measurement procedures for Madeira wine ageing prediction. In order to properly identify and quantify the chemical compounds qualified for characterizing wine evolution during the ageing period, chromatographic and spectroscopic analyses were carried out. Twenty-six samples, r...

The flavor pattern is a key quality feature in the wine industry. Being the result of a complex interplay of different classes of volatile compounds, it presents an important evolution during the final and longer phase of the wine production process: the ageing period. In this paper, we present a data analysis framework for supporting the proper mo...

Wine is one of the world's higher value agricultural products. The present work is centred on Madeira wine, a fine and prestigious example among Portuguese liqueur wines,with the main goal to deepen our understanding of relevant phenomena going on during the winemaking process, in particular during ageing of "Malmsey" Madeira wine. In this paper we...

Madeira wine has been studied with the main goal of acquiring a better understanding about the evolution of its properties over time. For that purpose, flexible and reliable data analysis tools were employed to characterize wines at different ageing stages, using flavour chromatography measurements. In this paper we present the results from such a...

Visual appearance is an important feature in the quality assessment of food products, since it plays a key role in the decisions made by consumers. Frequently, its evaluation is carried out by a panel of experts from the quality department who analyze, by visual inspection, samples of product taken from the process. It is well-known that such metho...