Freshness-indices of roasted coffee : monitoring the loss of freshness for single serve capsules and roasted whole beans in different packaging

With the growing demand for high-quality coffee, it is becoming increasingly important to establish quantitative measures of the freshness of coffee, or the loss thereof, over time. Indeed, freshness has become a critical quality criterion in the specialty coffee scene, where the aim is to deliver the most pleasant flavor in the cup, from highest quality beans. A series of intensity ratios of selected volatile organic compounds (VOC) in the headspace of coffee (by gas chromatography–mass spectrometry) were revisited, with the aim to establish robust indicators of freshness of coffee – called freshness indices. Roasted whole beans in four different packaging materials and four commercial capsule systems from the Swiss market were investigated over a period of up to one year of storage time. These measurements revealed three types of insight. First, a clear link between barrier properties of the packaging material and the evolution of selected freshness indices was observed. Packaging materials that contain an aluminum layer offer better protection. Second, processing steps prior to packaging are reflected in the absolute values of freshness indices. Third, differences in the standard deviations of freshness-indices for single serve coffee capsule systems are indicative of differences in the consistency among systems, consistency being an important quality attribute of capsules

Acrylamide in almond products

Acrylamide was determined in 86 different almond products, such as roasted almonds, almond-containing bakery products, raw almonds, and marzipan. The highest acrylamide concentrations were found in dark roasted almonds, while only moderate acrylamide contents were determined in bakery products. Roasting experiments under different process conditions showed that acrylamide increases with time and that temperature has a much stronger effect on acrylamide formation than time. During roasting reducing sugars are consumed faster and to a larger extent than free asparagine, suggesting that the content of reducing sugars may be a critical factor for acrylamide formation in roasted almonds. Acrylamide was found to decrease in roasted almonds during storage at room temperatur

Potential for acrylamide formation in potatoes: data from the 2003 harvest

Reducing sugars, free amino acids, and the potential for acrylamide formation were determined in more than 50 potato samples from the 2003 harvest in Switzerland. The reducing sugar content strongly correlated with acrylamide, whereas no correlation was found between acrylamide and free asparagine or the pool of free amino acids. The reducing sugar contents and the acrylamide potentials were higher in most of the cultivars tested than in the samples from 2002. This was probably due to the hot and dry summer of 2003. Monitoring sugars and amino acids during heating at 120°C and 180°C showed that glucose and fructose reacted much faster than sucrose and the amino acids. Glutamine was consumed to a larger extent than any of the other amino acids. During prolonged storage, the reducing sugars decreased considerably while only moderate changes in the free amino acids were observed. Altogether, glucose and fructose remain the critical factors for acrylamide formation in potatoes and represent the most feasible way of reducing the formation of acrylamide in potato product

Comparison of nine common coffee extraction methods: instrumental and sensory analysis

The preparation of a cup of coffee may vary between countries, cultures and individuals. Here, an analysis of nine different extraction methods is presented regarding analytical and sensory aspects for four espressi and five lunghi. This comprised espresso and lungo from a semi-automatic coffee machine, espresso and lungo from a fully automatic coffee machine, espresso from a single-serve capsule system, mocha made with a percolator, lungo prepared with French Press extraction, filter coffee and lungo extracted with a Bayreuth coffee machine. Analytical measurements included headspace analysis with HS SPME GC/MS, acidity (pH), titratable acidity, content of fatty acids, total solids, refractive indices (expressed in °Brix), caffeine and chlorogenic acids content with HPLC. Sensory analysis included visual, aroma, flavor and textural attributes as well as aftersensation. The technical differences in the extraction methods led to a higher concentration of the respective quantities in the espressi than in the lunghi. Regarding the contents per cup of coffee, the lunghi generally had a higher content than the espressi. The extraction efficiency of the respective compounds was mainly driven by their solubility in water. A higher amount of water, as in the extraction of a lungo, generally led to higher extraction efficiency. Comparing analytical data with sensory profiles, the following positive correlations were found total solids ↔ texture/body, headspace intensity ↔ aroma intensity, concentrations of caffeine/chlorogenic acids ↔ bitterness and astringenc

Exploring indicators of food choice for chimpanzees at Taï National Park, Côte d’Ivoire : aroma and antioxidants

This study explored the food choice for chimpanzees at Taï National Park, Côte d’Ivoire and attempted to link these to the aroma and antioxidants content. The focus was on the aroma composition and antioxidant content of the fruits of the tree Sacoglottis gabonensis (Baill.) Urb., S. gabonensis, at different ripeness stages, in order to elucidate potential drivers for the selection of presumably ripe fruits by the apes. Flavour analyses have revealed clear differences between the unripe, ripe and to a lesser extent also between ripe and overripe fruits. Eating fruits at a ripe stage implies that chimpanzees are rewarded with high level of macro-nutrients, e.g. carbohydrates together with low content of unwanted bitter compounds. Yet, ripe fruits do not represent a ripeness stage with highest antioxidant content and highest antioxidant content was found in unripe fruit, which is gradually decreasing while ripening

How can we measure the freshness of coffee?

With the growing demand for specialty coffee and the rising consumer awareness of quality in the cup, it is becoming increasingly important to establish objective and quantitative measures of coffee quality. A series of “freshness indices” were evaluated. This includes specific ratios between volatile compounds that are either typical for freshly roasted coffee or an expression of degradation and oxidation processes, analyzed by HS GC-MS. We report on results during storage for up to one year, for a range of commercial single serve capsule systems (ground coffee), as well as for whole roasted beans in packaging with different barrier properties. Parallel sensory measurements are in line with these instrumental results

Monitoring indoor air quality

People spend on average 80 to 90 percent of the day indoor. It is therefore important to understand what is the quality of the air that we breathe in these spaces? We have recently developed a GC-MS method for the analysis of indoor air samples that were collected on sorption tubes exposed for several hours to the atmosphere of the respective rooms. It consists in the thermal desorption from sorption tubes followed by cryogenic focusing at the inlet of the GC capillary, GC-separation and MS detection. Here we discuss the analytical methodology and review recent results