Survey of furan in foods and coffees from five European Union countries

Canned and jarred baby foods (74), canned and jarred adult foods (63) and 70 coffees sold in Belgium, Italy, Portugal, Spain and The Netherlands were analysed for their furan content using a validated automated headspace GC–MS procedure. Seven balsamic vinegars from Italy and Spain were also analysed. All 74 baby food samples contained detectable furan, with an average level of 37 ng/g. A total of 54 of 63 canned and jarred foods contained detectable furan with an average level of 24 ng/g. Levels of furan in coffee as consumed were very variable and reflected different preparation methods and coffee strengths. Over 50% of Italian samples contained more than 200 ng/g, whereas over 20% of Belgian coffees contained less than 21 ng/g furan. Some brews made from fine grained coffee contained much more furan than did brews made from normal or coarse grained coffee. Although furan was low in most instant coffees, two Italian products “instant espresso” and “instant mocha” contained about 150 ng/g furan. Balsamic vinegars from Spain contained 159–662 ng/g of furan; however, other samples from Spain and Italy contained only 6–25 ng/g.     

Intra- and interspecific mineral composition variability of commercial instant coffees and coffee substitutes: Contribution to mineral intake

The present paper reports the amount and estimated daily mineral intake of nine elements (Ca, Mg, K, Na, P, Fe, Mn, Cr and Ni) in commercial instant coffees and coffee substitutes (n = 49). Elements were quantified by high-resolution continuum source flame (HR-CS-FAAS) and graphite furnace (HR-CS-GFAAS) atomic absorption spectrometry, while phosphorous was evaluated by a standard vanadomolybdophosphoric acid colorimetric method.Instant coffees and coffee substitutes are rich in K, Mg and P (>100 mg/100 g dw), contain Na, Ca and Fe in moderate amounts (>1 mg/100 g), and trace levels of Cr and Ni. Among the samples analysed, plain instant coffees are richer in minerals (p < 0.001), except for Na and Cr. Blends of coffee substitutes (barley, malt, chicory and rye) with coffee (20–66%) present intermediate amounts, while lower quantities are found in substitutes without coffee, particularly in barley.From a nutritional point of view the results indicate that the mean ingestion of two instant beverages per day (total of 4 g instant powder), either with or without coffee, cannot be regarded as important sources of minerals to the human diet, although providing a supplementation of some minerals, particularly Mg and Mn in instant coffees. Additionally, and for authentication purposes, the correlations observed between some elements and the coffee percentage in the blends, with particular significance for Mg amounts, provides a potential tool for the estimation of coffee in substitute blends.     

Norharman and harman in instant coffee and coffee substitutes

Norharman and harman are two neuroactive β-carbolines present in several plants and thermally processed foods, including roasted coffee. The objective of this study was to evaluate their amounts in commercial instant coffee-based and coffee substitute beverages (n = 48), with variable amounts of coffee, chicory, barley, malt, and rye. All samples contained variable amounts of both β-carbolines, always with a higher proportion of norharman than harman. The highest levels (p < 0.01) were found in 100% instant coffees, with mean amounts of 3.8 μg/g and 1.5 μg/g for NH and H, respectively, followed by plain chicory. The lowest amounts were found in 100% barley, with 1.1 μg/g for NH and 0.3 μg/g for H. The NH and H content was statistically higher (p < 0.01) in all mixtures with coffee when compared to those without it. Nevertheless, and except for 100% barley, the amounts provided by beverages based on coffee substitutes are within those reported for standard coffee brews.     

Gender preference in hedonic ratings for espresso and espresso-milk coffees

Espresso, cappuccino and latte are new coffee products entering the daily lives of many consumers. There is increasing consumption of such speciality coffees but no sensory basis for new product development. This study was designed to meet this need. Preference in 100 consumers was studied using six espresso blends of coffee beans. Blends were specifically developed to match key European and North American styles. Products prepared were both espresso and espresso-milk coffees. It was observed that females and males had different preferences for espresso coffee but that this effect was reduced on addition of milk. Gender of target consumer, and end use of espresso, should be thus considered in developing coffee blends. In this way acceptability in specific or target groups of consumers can be maximised. In addition individuals may experience a development of appreciation of coffee character reflected in a change in preference.     

Acids in coffee. XI. The proportion of individual acids in the total titratable acid

22 acids in ground roast coffees and instant coffees were determined by GLC of their silyl derivatives (after preseparation by gel electrophoresis) or isotachophoresis. The contribution to the total acidity (which was estimated by titration to pH 8 after cation exchange of the coffee solutions) was calculated for each individual acid. The mentioned acids contribute with 67% (roast coffee) and 72% (instant coffee) to the total acidity. In the first place citric acid (12.2% in roast coffee/10.7% in instant coffee), acetic acid (11.2%/8.8%) and the high molecular weight acids (8%/9%) contribute to the total acidity. Also to be mentioned are the shares of chlorogenic acids (9%/4.8%), formic acid (5.3%/4.6%), quinic acid (4.7%/5.9%), malic acid (3.9%/3%) and phosphoric acid (2.5%/5.2%). A notable difference in the contribution to total acidity between roast and instant coffee was found for phosphoric acid and pyrrolidonecarboxylic acid (0.7%/1.9%). It can be concluded that those two acids are formed or released from e.g. their esters in higher amounts than other acids during the production of instant coffee.     

QUALITY OF FLAVORED YOGURT CONTAINING ADDED COFFEE AND SUGAR

Yogurts flavored with instant coffee (0.5, 0.7 and 0.9%) and sweetened with sugar (4 or 5%) and a control yogurt (no coffee or sugar) were evaluated for chemical, physical, microbiological and sensory properties. The added ingredients generally had no effect on the chemical, physical and microbiological quality of yogurts at day 1 after preparation as compared to the control. During 15 days at 5–7C, pH and lactic acid bacteria counts decreased (P < 0.05) and titratable acidity increased (P < 0.05) in all samples. Yogurts with 0.5% coffee flavoring and 4 and 5% sugar met Turkish Institute Standards for yogurt sensory quality when evaluated by a trained 10‐member panel. Yogurt flavored with 0.5% coffee and containing 5% sugar had most attributes rated in the “like” category by 50% or more of 51 consumer panelists.     

Use of healthier fats in biscuits (olive and sunflower oil): changing sensory features and their relation with consumers' liking

The aim of this study was to evaluate consumer acceptability of biscuits when saturated fat was replaced by olive or sunflower oil and to determine the sensory characteristics responsible for changes in acceptability. Ninety seven consumers evaluated the acceptability of six biscuit samples varying in the fat source (dairy shortening, olive oil and sunflower oil) and fat content (10.6% and 15.6%). Using a Check All That Apply question (CATA), consumers also evaluated sensory properties of biscuits. Results indicated that the replacement of saturated fat (dairy shortening) by vegetable oils had an effect on biscuit acceptability which depended on biscuit fat content. According to biscuits' acceptability data, three different clusters of consumers were identified. By using a multiple factor analysis, the relationship among sensory CATA data and acceptability of each cluster explained the different acceptability patterns of consumers. For most of consumers acceptability was related to attributes “crispy”, “easy to chew” and “biscuit flavour” which, for one group were perceived in shortening biscuits and, for another in both olive and shortening biscuits. However, for the third group of consumers, acceptability was only related to flavour attributes like “roasted flavour” or “biscuit flavour” that were perceived in vegetable oil biscuits which were the preferred biscuits while, shortening biscuits were disliked and perceived as having an “off flavour”.     

Recent developments in the manufacture of instant coffee and coffee substitutes

This paper describes modern production methods resulting from the developments that have been taking place recently in the field of instant coffee and coffee substitutes. Such developments involve new processing techniques to achieve higher extraction yields and improve extract concentration, and more efficient spray drying. A tabulated comparison of operating conditions when spray drying chicory, pure coffee and chicory/coffee mixtures is given.     

Influence of coffee/water ratio on the final quality of espresso coffee

Espresso coffee is a polyphasic beverage in which the physico‐chemical and sensory characteristics obviously depend on both the selection of ground roasted coffee and the technical conditions of the percolation process. The aim of this work was to evaluate the influence of the coffee/water ratio on the physico‐chemical and sensory quality of espresso coffee. Furthermore, the influence of botanical varieties (Arabica and Robusta) and the type of roast (conventional and torrefacto) on the selection of coffee/water ratio was studied. The relationship between pH and the perception of acidity intensity is discussed in relation to the influence of the coffee/water ratio, type of coffee and roast. The optimisation of other technical parameters in previous studies seemed to minimise the influence of an increase in the coffee/water ratio on the extraction of soluble and solid compounds. In fact, only some sensory attributes, such as bitterness, astringency and burnt, acrid and earthy/musty flavours were proposed as relevant to the selection of 6.5 g 40 mL^?1 or 7.5 g 40 mL^?1 in conventional roasted coffees (Arabica 100% and Robusta blend), and 6.5 g 40 mL^?1 in torrefacto roasted coffees. On the other hand, the addition of sugar during the roasting process in torrefacto roast coffees seemed to contribute to a higher generation of acids, melanoidins and other compounds by the Maillard reaction or caramelisation, which led us to select the lowest coffee/water ratio. Copyright © 2006 Society of Chemical Industry     

INTEGRATING SENSORY ANALYSIS AND HEDONIC EVALUATION FOR APPLE QUALITY ASSESSMENT

ABSTRACT

Apple cultivars were subjected to a consumer test in order to appreciate individual preferences and set up a protocol for a practical hedonic‐sensory evaluation. Cultivars subjected to the test were “Golden Delicious,”“Modì,”“Pink Lady” and “Fuji” of two different origins. Apples had the sensory profile defined by a trained panel and were evaluated by 154 consumers. According to their preferences, consumer population could be divided in six clusters. Consumer preference responses clearly associated the two “Fuji” and showed “Modì” and “Pink Lady” to have appeal on the same consumers groups. Besides expressing hedonic judgment, consumers were requested to indicate the positive sensory attributes determining their choice. Consumers appreciated “Golden Delicious” and “Fuji” on the basis of sweetness and aroma, while preferences for “Pink Lady” and “Modì” were expressed by consumers appreciating crispness, juiciness and a certain degree of acidity. The involvement of consumers in defining attributes driving preferences provides details useful for weighing up the consistency between consumers' response and sensory panel profile.

PRACTICAL APPLICATIONS

This work contributes to the knowledge on consumer preferences and concerning apple sensory quality. In particular, the tested varieties could be divided in three groups on the basis of perceived attributes. Knowledge of consumer preferences related to apple qualities can be a key point in planning production and marketing strategies. A protocol integrating sensory characteristics defined by a trained panel, hedonic consumer judgments and sensory preference drivers is proposed.     

Determination of 5-hydroxymethylfurfural and caffeine in coffee and chicory extracts by high performance liquid chromatography

5-Hydroxymethylfurfural and caffeine in instant coffee and coffee/chicory powders have been determined by HPLC on Hypersil (solvent 5% isopropanol/dichloromethane). The former compound is characteristic of chicory and could be used to distinguish between coffee and coffee/chicory mixtures.     

Coffee mixtures—Spectrophotometric method for the determination of coffee content

The method described in this paper gives results which are good approximations of the actual coffee contents of roasted coffee/roasted chicory and roasted coffee/roasted fig mixtures.It has also been applied to coffee and chicory essence, cereal products and instant coffee/chicory, instant coffee/cereal/chicory mixtures.     

Survey of Canadian retail coffees for ochratoxin A

One-hundred and one specimens of coffee were gathered from retail outlets across Canada and analysed for ochratoxin A. Seventy-one specimens were roasted beans or roasted ground coffee, and 30 were instant (or 'soluble') coffees. All samples were extracted with methanol-sodium bicarbonate. The extracts were cleaned up either by immunoaffinity column chromatography or by a combination of solid-phase extraction and immunoaffinity column chromatography. Ochratoxin A was quantified by liquid chromatography (LC) with fluorescence detection. The minimum quantifiable level was 0.1 ng g^-1. Ochratoxin A was present, above the minimum quantifiable level, in 42 (59%) of 71 beans and ground coffee and in 20 (67%) of 30 instant coffees. The mean ochratoxin A level in the positive samples of beans and ground coffee was 0.6 ng g^-1, and the mean level in the positive samples of instant coffee was 1.1 ng g^-1.     

Occurrence of 3-chloropropane-1,2-diol and its esters in coffee

Fifteen coffee samples comprising green, roasted, decaffeinated and instant coffees were analysed for their content of free and bound 3-chloropropane-1,2-diol (3-MCPD). Green coffees contained only traces of the free 3-MCPD. 3-MCPD in roasted coffees was found at the level of 10.1–18.5 µg/kg. The highest 3-MCPD level of 18.5 µg/kg was found in one instant coffee sample and in coffees with very long time application during roasting. The final colour of the roasted coffee beans was directly linked to the 3-MCPD formed, the darker beans having the greatest concentration, and arabica coffees contained lower 3-MCPD levels than robusta coffees. The level of bound 3-MCPD varied between 6 µg/kg (soluble coffees) and 390 µg/kg (decaffeinated coffee) and exceeded the free 3-MCPD level 8–33 times. Arabica coffees contained higher levels of the bound 3-MCPD than robusta coffees. The recognised precursors of 3-MCPD (salt, glycerol, lipids) were also determined and their influence on the formation of the free and bound 3-MCPD was discussed.     

Assessment of instructions on panelist cognitive framework and free sorting task results: A case study of cold brew coffee

As the free sorting task becomes more common in sensory science, methodological research is needed to determine best practices for the test. Previous studies have shown that asking attribute-specific, “analytical” questions can bias the answers participants give to later “holistic” questions in a survey. For the free sorting task, this has led researchers to recommend only asking subjects to label or describe groups of products after they have finished sorting, but this approach is not based on empirical research. The present study investigated whether the separation of sorting and labeling steps is necessary by having 80 panelists sort 12 cold brew coffee samples in 3 conditions: labeling and describing the groups afterwards, at the same time, or not at all. Results were analyzed with DISTATIS, Hierarchical DISTATIS, and permutation tests. This work is novel in investigating the effect of labeling instructions on sorting results and provides some interesting insight into sensory impact of coffee bean parameters on cold brew coffees. No configurational differences were found based on the timing of labeling instructions and 38% of panelists labeled their groups without being told, suggesting future researchers may request that subjects label when convenient. While the most distinctive samples were the dark roast coffees, a large subgroup (n = 36) sorted the coffee samples partially based on country of origin. Given the lack of effect from different sorting instructions and the tendency for spontaneous, simultaneous labeling, simultaneous labeling is suggested as best practice for future sorting tasks.     

Consumer Acceptance of a Polyphenolic Coffee Beverage

The objective of this study was to determine if Chardonnay grape seed pomace (GSP), a waste stream of wine production, could be used as a functional ingredient in brewed coffee. Two consumer panels were conducted to assess the acceptance of coffee at coffee replacement (w/w) values of 0% (control), 6.25%, 12.50%, 18.75%, or 25% GSP. The 1st consumer panel (n = 80) assessed the coffee samples served “black.” The 2nd panel (n = 67) assessed the coffee samples with adjustment (that is, sweeteners, milk, and cream) options available. Consumer sensory evaluation involved evaluating the 5 treatments individually for acceptance of appearance, aroma, taste/flavor, and overall acceptance using a 9‐point hedonic scale. A check‐all‐that‐apply questionnaire surveyed the sensory attributes describing aroma, appearance, and taste/flavor of the samples. Oxygen radical absorbance capacity was used to measure the effects of antioxidant levels in GSP coffee samples. Results showed that GSP could be added at 6.25% replacement without significantly affecting the overall consumer acceptance of coffee compared to the control (0% GSP). Above 6.25% GSP supplementation, the coffee beverage was described as more tan, milky, watery/dilute, and mild, and was generally less accepted by the consumers. GSP also increased the antioxidant capacity of the coffee compared to the control (0% GSP), with no significant differences among replacement values. Therefore, 6.25% GSP replacement is recommended for creating coffee beverages acceptable to consumers. Further in vivo investigation may substantiate the free‐radical scavenging capacity of GSP coffee and its potential health benefits.     

Relative Efficiency of Paired Comparisons and Rank Order in Preference Discrimination among Coffees

SUMMARY: Four samples of instant coffee, which varied only in stength, were preference tested by 1152 coffee drinkers by three different methods. Half tested by paired comparisons with two pairs served, one-third used 3-sample rank order and one-sixth used 4-sample rank order. The direction of preference was the same with all methods. The weaker coffees were preferred over the stronger ones. Within the paired comparison method, discrimination was slightly better with the second than with the first pair. Paired comparisons and 3-sample rank order discriminated equally well. Discrimination by 4-sample rank order was slightly poorer than with the other two methods when the between-sample differences were small.