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Oyster refinement using land-based pond systems is a new activity in the Dutch oyster sector. It increases the oyster's tissue weight and changes its sensorial properties. However, the response of Dutch consumers towards refined oysters is unknown. The research aim was to gain insight into the importance of oyster quality parameters, drivers for oyster consumption, and acceptance of refined oysters by Dutch consumers, taking into account the information given to them about the product and process.; Results: Taste, texture, and odor are the most important oyster quality characteristics for Dutch consumers. The outcome of questionnaires showed that willingness to buy and pay is influenced by factors such as the oysters' country of origin, cultivation area, and flavor profile. Refinement did not affect willingness to buy and pay. Furthermore Dutch consumers seem to have a preference for the flavor profile of refined oysters. Consumer evaluation showed that refined Pacific cupped oysters were perceived as sweeter compared with non-refined oysters. When information on the cultivation process was disclosed, overall appreciation of refined oysters by consumers increased.; Conclusion: New insights in the importance of oyster quality characteristics for Dutch consumers are generated that can be used in the development of refined Pacific cupped oysters. © 2018 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.; © 2018 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

10 pages, 4 figures, 5 tables, Oyster refinement, a common practice in France, is aimed at increasing the weight of oyster tissue and influencing the taste properties of the refined oysters. Refinement usually takes place in land-based systems where the oysters are fed with relatively high concentrations of microalgae. In this study the impact of feeding Skeletonema costatum and Rhodomonas baltica on the biochemical composition and sensory characteristics of Pacific cupped oysters (Crassostrea gigas) from the Eastern Scheldt during land-based refinement was studied. After a feeding period of four and seven weeks market-sized oysters were sampled for the analysis of fatty acids, free amino acids and volatile organic compounds and for a sensory evaluation by consumers and an expert panel. The algae Skeletonema costatum showed a lower ∑ PUFA, ∑ n − 3, ∑ n − 6, C18:2n6, C18:3n3, C18:4n3, C22:6n3 content as compared with Rhodomonas baltica. These differences were also reflected in the fatty acid profile of the oysters fed with the corresponding algae diets. Furthermore, general linear model and principal component analysis showed marked differences in free amino acids and volatile organic compound content between Skeletonema, Rhodomonas fed oysters and reference oysters. For example, threonine, glutamine, leucine, histidine, (E)-2-hexenal, (E)-2octenal, (E)-2-octen-1-ol, (E,E)-2,4-octadien-1-ol, (E,Z)-3,6-nonadien-1-ol and (Z,E)-2,6-nonadienal contents were higher in Skeletonema fed oysters compared to Rhodomonas fed oysters. Sensory differences between the experimental oyster groups were shown. Skeletonema fed Pacific cupped oysters were characterized by a stronger seaweed flavor, higher perceived sweetness and a firmer texture in comparison with Rhodomonas fed oysters. Naïve consumers were only able to differentiate between Rhodomonas fed oysters and reference oysters, This research was partially funded by the project Zilte Parels (Nationaal Regieorgaan Praktijkgericht Onderzoek SIA) and by the Interreg IV Project AquaVlan

A new, energy efficient production process for French fries was developed and evaluated. Superheated steam (SHS) was used for evaporation of water instead of pre-drying with air and par-frying with oil. The product was frozen by vacuum cooling. Unfortunately, with this process it was not possible to reach the quality of conventional French fries. Sensory analysis indicated that the main quality defect was a tough crust with a fatty appearance. Confocal Scanning Laser Microscopy showed that this was caused by skin formation on the surface during both SHS drying and vacuum cooling. A frying step was necessary to obtain a porous crust. A satisfactory product quality was feasible after drying with SHS instead of air. Due to the concessions made for the product quality, the final energy reduction was limited. Nevertheless, this study has gained more insight into how processing affects potato tissue on micro-scale and it has shown that a porous structure is essential for good quality French fries.

The aim of this study was to isolate and identify odour active compounds from French fries at mouth conditions. Volatile compounds were released from French fries by purge-and-trap, trapped on Tenax TA, and identified with GC–MS. GC–olfactometry was used to determine odour active compounds with a trained panel using the detection frequency method. A total of 122 compounds were identified of which 85% originated from either sugar degradation and/or Maillard reaction and 15% from lipid degradation, based on relative areas. About 50 odour active compounds were, due to coelution, responsible for 41 odours perceived by the panel. 3-Methylbutanal and 2-methylbutanal, hexanal, 2,3-dimethylpyrazine, 2-methylpropanal, 2,3-butanedione, pyridine, heptanal, 2,5-dimethylpyrazine and/or 2,6-diemethylpyrazine and/or ethylpyrazine, dimethyl trisulfide, octanal, phenylacetaldehyde, 2,5-diethylpyrazine, (E)-2-nonenal, 3-methylbutanoic acid and/or 2-methylbutanoic acid, (E,Z)-2,4-heptadienal, (E)-2-octenal, 5-ethyl-2,3-dimethylpyrazine and/or 2-ethyl- 3,5-dimethylpyrazine, nonanal, and tentatively 2-methylpyrrole had the highest detection frequencies. This resulted in a strong malty and fried potato note, combined with caramel/buttery, green, spicy, and deep-fried notes. Also chemical and sweaty odours were observed.

The effects of seed treatments, including cooking, popping, germination and flour air classification on several components of Amaranthus caudatus and A. cruentus seeds, including oil, sugars, fibre, minerals and vitamins were studied. The lipid, crude and dietary fibre, ash, and sugar contents were 71, 43, 140, 30 and 18 g kg-1 in raw A. caudatus and 85, 39, 134, 40 and 22 g kg-1 in raw A. cruentus seeds, respectively. Sucrose was the dominant sugar in the raw and thermal treated seeds of both species, while glucose and galactose were the dominant ones in the high protein and the germinated seed flours. Phosphorus, potassium, magnesium and calcium were the dominant minerals in the raw seeds of both species. Air classification increased the content of minerals by more than 35% while thermal treatments did not affect their content and germination increased the calcium and zinc contents. The ascorbic acid contents were 0.030 and 0.023 g kg-1 sample in raw A. caudatus and A. cruentus seeds, respectively. All the treatments reduced the ascorbic acid content, with a high effect for the air classification and the germinated seeds dried at 90 °C. The levels of vitamin B complex, including niacin, niacinamide, pyridoxine and riboflavin were increased in the high protein flour fraction (protein contents of these fractions of A. caudatus and A. cruentus were 263.9 g kg-1 and 246.6 g kg-1, respectively) and decreased in the thermal treated flours. Germination mostly increased the amounts of those vitamins while drying reduced their amounts.

The nutritional value of raw and popped (similar to popcorn preparation) seed proteins of two amaranth species, Amaranthus caudatus L and A cruentus L, was investigated. After popping, the true protein content in A caudatus and A cruentus decreased by 9 and 13% respectively. Among the amino acids, the loss of tyrosine due to the popping effect was the highest, followed by phenylalanine and methionine. Leucine was the first limiting amino acid in the raw samples, followed by lysine, while the reverse order was observed in the popped samples. The in vivo protein quality of raw and popped seeds was tested with male weanling rats and compared with wheat flour and casein samples. There was no difference between the in vivo digestibility of the raw and the popped seeds, although the in vitro digestibility was slightly higher for the popped samples. The protein efficiency ratio (PER) for all the amaranth seed samples was higher than that for the wheat sample, while the PER for the raw amaranth seed samples was close to that for the casein reference protein. The rat blood serum levels of total cholesterol, triglycerides and high-density lipoprotein cholesterol for all the amaranth samples were lower than those for the reference protein, while the wheat flour sample showed the lowest values. (C) 2004 Society of Chemical Industry.

The physical properties of starches from 3 typical Chinese sweet potato varieties (SuShu2, SuShu8, and XuShu18) were studied in relation to their noodle-making performance. The starch gel properties of SuShu2 differed from those of SuShu8 and XuShu18. As determined by both instrumental and sensory analysis the use of SuShu8 starch resulted in better noodle quality compared to XuShu18 and SuShu2 starches. The gel properties and noodle quality of the 3 sweet-potato starches were clearly different from those of mung-bean starch. Correlation between starch noodle quality and gel properties of the original starches was established.

Food packaging, although an integral part of the food chain, has a major drawback in that, often, the packaging material interacts with the flavor constituents of the food, causing either a selective or an extensive loss of desirable food flavors or absorption of undesirable off-flavors from the packaging material, thereby resulting in an eventual loss of quality of the packaged food item. The process is called "scalping" and is of great concern to the food industry, which is always looking out for new avenues in "packaging solutions" for its final product quality needs. The review highlights the various attributes of the scalping process, explores approaches to the reduction of the manifested undesirable effects, and covers other relevant aspects.

Acetone extracts (AE), deodorised acetone extracts (DAE), and deodorised water extracts (DWE) from leaves of horehound (Marrubium vulgare L. ) were tested for their antioxidant activity in rapeseed ( Brassica napus L.) oil at 80 °C. Well investigated antioxidants containing extracts (AE and DAE) of sage (Salvia officinalis L.) were used for comparison purposes. The effect of the extracts on the edible oil stability was assessed by measuring weight gain, peroxide value, and the UV absorption. The antioxidant activity of AE and DAE of horehound were comparable to the antioxidant activity of AE and DAE of sage. For both plants AE was shown to have better antioxidant properties than DAE. The volatile components of horehound were hydrodistilled and analysed by GC and GC/MS. Totally, 47 components were identified in the essential oil (EO), the main ones being (Z)- β-farnesene, βcaryophyllene, (E)-hex-2-enal, α-humulene, and germacrene D. Thirtynine constituents are reported in M. vulgare for the first time.

Taste recognition threshold concentrations (TRTC) of styrene were determined in samples of oil-in-water emulsions (30–300 g kg−1 oil) and yoghurts (1–30 g kg−1 fat), spiked with styrene. The observed TRTC increased linearly with increasing fat content and ranged from 0–3 to 2–1 mg kg−1 for the emulsions and from 36 to 171 g kg−1 for the yoghurts. Styrene equilibrium partition coefficients between emulsions and their respective vapour phases were determined. The concentrations of styrene in the continuous aqueous phase of the emulsions and yoghurts were calculated at the TRTC. The styrene concentrations in the continuous phase had constant values of about 15 g kg−1 indicating that perception of styrene for oil-in–water emulsions is determined by the aqueous phase of the emulsion. The concentrations of styrene in the vapor phases above the emulsions and yoghurts were also calculated and were found to be constant at the TRTC. This relationship probably resulted from the equilibrium of distribution of styrene between the respective phases. Commercial yoghurt packed in polystyrene beakers contained styrene levels in the range 2–11 g kg−1, much lower then the TRTC reported.

A panel of 48 assessors evaluated a taint in water, packed in test pouches made of low density polyethylene (LDPE) lined aluminium. This panel agreed upon eight descriptive attributes (in Dutch): metallic (metaal), syn thetic (synthetisch), dry (droog), rough (stroef), astringent (wrang), musty (muf), sickly (wee) and penetrating (doordringend). Fourteen assessors, selected with a standard triangle test, were asked to judge intensities for these attri butes on a visual analogue scale. Factor analysis reduced the original data- matrix to a six dimensional one losing only 6.4% of the original variance. Syn thetic and penetrating loaded high on one factor as well as rough and astringent on another one. Musty, sickly, metallic and dry loaded high on sepa rate factors. Direct dynamic headspace analysis of the LDPE-lined test pouches gave mainly peaks of branched alkanes of 12 carbon atoms. However, dynamic head space analysis of water in contact with the LDPE layer of the test pouches showed no alkanes but (C4 - C11) aldehydes and ketones.

Polythene terephthalate (PET) is frequently used as a packaging material for mineral water and other non-alcoholic beverages. PET contains detectable amounts of acetaldehyde, which is able to migrate to its packed product. An automated headspace gas chromatographic method for the determination of acetaldehyde has been developed and was used for the quantification of acetaldehyde in aqueous food products and their PET packages. A cold trap, mounted in the GC oven, between the auto sampler and analytical column was introduced as a new application. The detection limit of acetaldehyde was found to be 3 ng/ml with a standard deviation of 3%. The contents of acetaldehyde found in carbonated mineral water and lemonade ranged between 11 ng/ml and 7447 ng/ml, while the contents of acetaldehyde in the PET packages ranged from 1.1 microgram/g to 3.8 micrograms/g.

One of the phenomena in food packaging interactions is flavour absorption. Absorption of flavour compounds from food products into food-packaging materials can result in loss of flavour compounds or an unbalance in the flavour profile changing a product's quality. The food matrix influences the amounts of absorbed flavour compounds; the presence of oil or fat especially determines the ability to absorb flavour compounds from the food to the package. On the other hand, the polarity of the flavour compound itself is a characteristic that also influences the level of absorption into synthetic polymers. A model based on the effect of the polarity (log P) of flavour compounds and on their partitioning coefficients between the food (matrix) and the packaging material is described. The model can be used for predicting absorption of flavour compounds from foods into LLDPE. However, an attempt to apply the proposed model on real foods shows serious limitations of the model for (very) low fat products. Predictive values deviate from the measured values, probably due to other interaction phenomena, e.g. with proteins. Predictive and measured values from a product with a substantial amount of fat match much better, suggesting that the model is valid for products having a substantial amount of (free) fat.

Styrene and ethylbenzene are present in detectable amounts in polystyrene packaging materials and migration of these compounds may cause a taint of the packed food. The effect of mixtures of styrene and ethylbenzene on the detection threshold concentration in a 5% oil-in-water emulsion was investigated with the constant stimulus differences test. The detection threshold concentrations of the individual compounds in the emulsion were found to be 1.0 ppm for styrene and 3.0 ppm for ethylbenzene. Linear regression of the percentages of correct answers and the logarithm of the sum of the concentrations of both compounds in the mixtures expressed as fractions of their threshold concentration gave the following relationship: % of correct answers = 42.5 x log (sum of threshold fractions) +74.8 (r = 0.87). Calculation of the sum of threshold fractions at the 75% point of correct answers gave a value of 1.0, which clearly indicates that the effect of mixing of styrene and ethylbenzene is additive at sub-threshold levels in a 5% oil-in-water emulsion.

Polystyrene packaging material taint was sensorily evaluated in cocoa powder for drinks and chocolate flakes using short-cut signal detection measures on differences between control and test samples and on recognition of styrene. No differences were observed in cocoa powder for drinks and plain chocolate flakes treated with 0.5 dm2 polystyrene of 1 mm thickness. However, differences were detected in milk chocolate flakes and plain chocolate flakes, which were in contact with a larger area or thicker polystyrene packaging material. The latter results were confirmed by the styrene recognition test, so polystyrene is a potential source of off-flavour for chocolate products. The amount of residual styrene in the polystyrene used was about 320 ppm, while the amounts of styrene ranged from 7 to 132 ppb in cocoa drinks and from 414 to 1447 ppb in chocolate flakes.

Uronides and saccharides were determined in the ethanol-insoluble residue of some fruits and vegetables, and in the pectin, hemicellulose and cellulose fractions of that residue. For molecular absorption spectrometry of uronides, enzymic, acidic and alkaline extraction were compared. The sugar composition was determined by gas chromatography after enzymic hydrolysis and trifluoroacetic acid (concn. 2 mol/1) or Saeman hydrolysis [sulphuric acid (concn. of H+ 0.8 mol/1 or 2 mol/1)]. Uronide contents found by molecular absorption with m-hydroxydiphenyl and copper binding were of the same order of magnitude. Saccharide composition of samples and fractions varied widely.