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Background The very recently released EFSA's scientific opinion on the safety of dried (whole or ground) Tenebrio molitor larvae (yellow mealworm) considering their uses in various food products and the following approval by The Standing Committee on Plants, Animals, Food and Feed, brought T. molitor into the spotlight. This is EFSA's first opinion on edible insects as a novel food pursuant to Regulation (EU) 2015/2283. Scope and approach This review aims to summarize existing information regarding the features that may corroborate the sustainability and increase the acceptability of T. molitor larvae as food ingredient. Towards this end, aspects related to rearing and farming conditions, nutrient content and technological approaches for the recovery of protein and lipid fractions are addressed. Special emphasis was posed on their protein techno-functional properties and the development of new T. molitor larva-based food products. Key findings and conclusions The larvae of yellow mealworm are considered among the most promising alternatives to address the predicted deficiency of conventional food protein. Owing to their notable protein, lipid, vitamin, and mineral content, they could serve as future ingredients for industrial purposes (e.g. substitutes of traditional animal sources) bringing environmental and economic advantages. Several methods of T. molitor larvae protein extraction have been studied leading to different characteristics of the final protein preparations. Compared to conventional protein sources the protein fraction of T. molitor has not been much investigated with respect to its physicochemical and techno-functional properties, the knowledge of which is essential to allow their effective inclusion in food formulations.

Undoubtedly, all pivotal advances in a great number of scientific fields rely on advances in chemistry. [...]

Edible insects have recently attracted research attention due to their nutritional value and low environmental footprint.

Lemon juice was mixed with different carrier materials (maltodextrin, gum Arabic, carboxymethylcellulose) and dehydrated by nano spray drying, conventional spray drying and freeze-drying technique....

Wheat flour was partially replaced with blackcurrant pomace, soluble, and insoluble dietary fibre in dough and bread formulations. The impact of blackcurrant fibre on physical properties of doughs and breads was probed using a set of complementary physicochemical techniques. The effect of fibre on aromatic profile of substituted breads was performed using analysis of volatile compounds. Analysis of fibre-substituted doughs and breads revealed that supplementation with pomace or insoluble fibre at concentrations >5% w/w or with pectin at concentrations >0.5% w/w alters their overall physicochemical responses. Pomace and pectin primarily acted as water-binders and decreased the extent of gluten hydration but insoluble fibre did not bind water to the same extent suggesting higher interaction capacity between its cellulosic components and gluten proteins resulting in formation of stiffer doughs. More than one hundred volatiles were determined with alcohols, furan derivatives and aldehydes being the major aromatic compounds.

The effect of the maize germ oil bodies in the form of a highly stable emulsion as a substitute for cow milk fat globules was investigated on the textural, physicochemical and sensory properties of a yoghurt-like product using a commercial yoghurt culture. The natural emulsion gave a satisfactory acidification kinetics pattern and an acid gel with a liquid-like structure. Gel formation was enhanced by skim milk incorporation, even more effectively when compared with cow milk with equal total solid content (16%, w/v), as determined by acidity, water holding capacity, syneresis, rheological and texture profile analysis. Studies on microbiological, physical and oxidative stability of the fortified yoghurt-like product reflect its quality assurance upon refrigerated storage. Different classes of endogenous bioactive constituents (mono- and polyunsaturated fatty acids, tocopherols) and volatile compounds derived from maize germ contribute to its high quality.

In this study, the aroma profile of 10 single origin Arabica coffees originating from eight different growing locations, from Central America to Indonesia, was analyzed using Headspace SPME-GC-MS as the analytical method. Their roasting was performed under temperature–time conditions, customized for each sample to reach specific sensory brew characteristics in an attempt to underline the customization of roast profiles and implementation of separate roastings followed by subsequent blending as a means to tailor cup quality. A total of 138 volatile compounds were identified in all coffee samples, mainly furan (~24–41%) and pyrazine (~25–39%) derivatives, many of which are recognized as coffee key odorants, while the main formation mechanism was the Maillard reaction. Volatile compounds’ composition data were also chemometrically processed using the HCA Heatmap, PCA and HCA aiming to explore if they meet the expected aroma quality attributes and if they can be an indicator of coffee origin. The desired brew characteristics of the samples were satisfactorily captured from the volatile compounds formed, contributing to the aroma potential of each sample. Furthermore, the volatile compounds presented a strong variation with the applied roasting conditions, meaning lighter roasted samples were efficiently differentiated from darker roasted samples, while roasting degree exceeded the geographical origin of the coffee. The coffee samples were distinguished into two groups, with the first two PCs accounting for 73.66% of the total variation, attributed mainly to the presence of higher quantities of furans and pyrazines, as well as to other chemical classes (e.g., dihydrofuranone and phenol derivatives), while HCA confirmed the above results rendering roasting conditions as the underlying criterion for differentiation.

It is challenging to establish a correlation between the agronomical practices and the volatile profile of high-value agricultural products. In this study, the volatile metabolome of walnut oils from conventional and organic farming type was explored by HS-SPME-GC-MS. The SPME protocol was optimized after evaluating the effects of extraction time, extraction temperature, and sample mass. The optimum parameters involved the extraction of 0.500 g walnut oil at 40 °C within 60 min. Twenty Greek walnut oils produced with conventional and organic farming were analyzed and 41 volatile compounds were identified. The determined compounds were semi-quantified, and further processed with chemometrics. Agglomerative hierarchical clustering (AHC) and principal component analysis (PCA) were used. A robust classification model was developed using sparse partial least squares–discriminant analysis (sPLS-DA) for the discrimination of walnut oils into conventional and organic, establishing volatile markers that could be used to guarantee the type of farming.

In this study, intermolecular interactions and structure formation between hemp protein isolate (HPI) and gum Arabic (GA) were investigated to unravel their complexation mechanisms. For this purpose, structural transition as a function of pH (2.0-7.0) and protein to polysaccharide ratio (HPI:GA, R = 0.5:1-13:1 w/w) was evaluated via turbidimetric analysis, ζ-potentiometry, state diagram construction and coacervate yield. It was proved that critical phase transition pH shifted to higher values with R increase, until reaching a plateau at ratio 10:1, with complexes to be formed even at pH region where both biopolymers were negatively charged. The shift of pH value, where maximum turbidity was noticed (pHopt), was well in accordance with net charge neutrality of HPI-GA mixtures found by electrophoretic mobility measurements. Maximum coacervation, occurred at ratio R = 2:1 and pHopt = 3.5, was depicted by the highest yield (92%), while morphological characteristics of liquid as well as freeze-dried HPI-GA coacervates, obtained through optical and scanning electron microscope measurements, gave a further perception of the associative processes during complex coacervation. Additionally, the molecular interactions between HPI and GA were confirmed by Fourier transform infrared spectroscopy (FTIR) revealing primarily electrostatic interactions with secondary stabilization of hydrogen bonds. Therefore, these findings could provide useful information for the development of HPI - GA coacervates as a potential bioactive encapsulation means.

Flavour retention in freeze-dried complex coacervates prepared with sodium caseinate and carboxymethylcellulose was followed over storage for 20 days at two relative humidities (0 and 54%) and temperatures (25 and 45 °C). Beta -pinene was used as a model volatile compound. Avrami’s equation mathematical model was equipped to describe the correlation between release rate and storage time. In general, volatile’s retention in the dried powder was considerably affected by the storage conditions along with the wall material characteristics (e.g. protein/polysaccharide ratio, presence of reticulating agents, i.e. glycerol and tannic acid) as a greater rate of release was observed at high relative humidity (RH) and temperature values and low biopolymer addition levels. Moreover, the Arrhenius activation energy E a was reduced by increasing RH from 0 to 54% while it got either positive or negative values indicating that the release of β -pinene was either related or not to temperature. Rehydration of dried powders in high humidity air conditions and the induced reduction of their effective surface area may account for the decrease of β -pinene retention. Glycerol addition resulted in higher retention of the volatile compound in the powder stored at low RH and temperature (0% RH, 25 °C) as compared to other storage conditions, which was further confirmed by the remarkable increase of half-life release t 1/2 from 29 to 9303 days, as this was calculated from the Avrami’s equation mathematical model.

This work aimed to investigate the possible impact of the chemical composition of gum arabic (GA) on the interactions and complexation mechanism with gelatin (G). For this purpose, two gum arabic samples were selected differing in the content of their arabinogalactan protein fraction (AGP), i.e. low (7%, GA7) and high (14%, GA14). The complex coacervates formation process was studied as a function of pH (from 7 to 2.4) and G:GA mixing ratio (1:2, 1:1, 2:1, 4:1, 6:1 w/w) by following changes in turbidity, ζ-potential and absorption of methylene blue – biopolymers mixtures. The complexation between the biopolymers (G-GA7 and G-GA14) was found to be stronger at a ratio of 1:1 and pH 3.7, where the highest yield (∼71%) was observed. The formed coacervates were examined using laser diffraction technique and optical microscopy along with Scanning Electron Microscopy, Fourier Transform Infrared analysis and Differential Scanning Calorimetry. Although both G:GA systems exhibited a similar behavior, some differences were observed. More specifically, results revealed that GA14 affected the surface charge characteristics of the G-GA complexes to a greater extent than GA7, while the corresponding liquid coacervates were more spherical, with a smoother surface and not aggregated. Additionally, G-GA14 complex coacervates were characterized by a more uniform morphology and size distribution along with a higher thermal stability implying thus a greater effectiveness of this system for the encapsulation of heat-sensitive materials.

Sodium caseinate or whey protein isolate-carboxymethylcellulose microcapsules were prepared by the complex coacervation method and loaded with β-pinene as a model volatile compound. The effect of varying the concentration of two food-grade reticulating agents, namely glycerol and tannic acid, on the effectiveness of volatile constituent's encapsulation was investigated. The produced microcapsules were characterised in terms of encapsulation process parameters (yield, loading, efficiency) and morphology, and the results were explained in accordance with Fourier-transform infrared spectroscopy and thermogravimetric analysis. The β-pinene's content was measured by gas chromatography. Glycerol addition led to a more than twofold increase in encapsulation efficiency, while the incorporation of tannic acid did not succeed to enhance it. Additionally, a more plastic than powdery texture and a more consistent structure with low porosity was obtained when glycerol was used. Both reticulating agents were found to act through hydrogen bonding as well as hydrophobic interactions. Molecular size difference between glycerol and tannic acid were considered responsible for the observed dissimilarities.

Sesame seed paste is a highly nutritious food product which, upon long-term storage, tends to exhibit undesirable phenomena of oiling-off and particle sedimentation. The ability of rich-in-fibre aqueous extraction powders originating from oleaginous raw materials to enhance the physical stability of sesame paste is investigated in this study. Results The extraction residues remaining after treating hazelnut, sesame seed or maize germ with aqueous media in order to extract and exploit their oil bodies, were collected, dehydrated and milled into fine powders. The powders were then incorporated at various levels into a commercially available sesame paste product to assess their potential as paste stabilisers against oil separation. The solids from maize germ exhibited the highest stabilising ability followed by the solids from hazelnut. In contrast, the solids originating from the sesame seed were less effective in stabilising the sesame paste. Shear stress-rate of shear measurements of sesame paste incorporating the extraction residue solids were conducted in an attempt to explain the different stabilising behaviour of the three powders. Conclusion The intensity of interactions between the incorporated solids within the sesame paste structure may determine the rheological properties of the blend and hence its stability against oiling-off upon long-term storage. ? 2016 Society of Chemical Industry

A set of seven commercial white wine samples (W1–7) produced from the cultivar Malagousia and obtained directly from the cellar 4 months after winemaking were subjected to accelerated oxidation (55 °C, 11 days). The correlation of browning susceptibility with compositional data, as well as the effect on phenolic content using simple assays, and the radical scavenging activity (DPPH·, ABTS·+) were examined. Calculated browning rate constants (k) varied by 1.03–2.66-fold among pairs of samples. Thus, despite the fact that samples originated from the same cultivar, differences were significant in some cases. No correlation was observed between browning and total or free sulfur dioxide, total iron, copper or other compositional parameters (total phenol, total hydroxycinnamates, total flavanol, catechin, epicatechin content, etc.), except for the grape reaction product/caftaric acid ratio (0.802, p = 0.017). The later suggested that wine must elaboration might be important for white wine oxidative stability, and its contact with oxygen should be avoided or minimized. Addition of ascorbic acid at the maximum level detected in the tested wines (70 mg/L), to one of the samples free of ascorbic acid but containing the highest level of total (100 mg/L) and free SO2 (30 mg/L) among these, had a negative effect. However, one of the samples containing ascorbic acid (33 mg/L) was resistant to oxidation. The molar ratio of free SO2 to that of ascorbic may affect browning susceptibility; therefore, the use of ascorbic acid should be made with caution. Chemometrics could be useful to provide prediction of browning susceptibility in relation to compositional data. The radical scavenging activity decreased with a significant correlation between the loss in DPPH· scavenging and ascorbic acid content (r = 0.845, p = 0.008). The changes in total flavanols did not follow a clear trend, whereas the spectrophotometric monitoring of total hydroxycinnamate was not informative due to interferences with browning products. Present findings are expected to be useful for those involved in white wine production.

Τhe chemical composition, aroma profile, particle size distribution, and foaming behaviour at two temperatures (4 and 65 °C) of sesame seed (SSE) aqueous extracts were investigated. SSEs were previously subjected to either roasting or blanching and the foaming properties of the obtained extracts were compared with those of cow milk and a commercial soy beverage. The effect of the addition of gums was also studied. Extracts obtained after SSE blanching presented inferior foaming properties in comparison to the roasted ones. Generally, SSE extracts presented a foaming behaviour comparable to that of soy beverage but inferior to that of cow milk, being much closer in the case of 65 °C, probably due to more extensive unfolding of globular proteins, resulting to their more efficient adsorption at the air-liquid interface. Χanthan gum addition led to a remarkable improvement of the foam stability owing to its ability to retard liquid's movement by inducing viscosity increase, while the addition οf guar and iota-carrageenan gums either reduced or did not significantly affect it.

The present work is part of an effort for the holistic, environmental-friendly exploitation of maize milling by-product and emphasizes on the utilization of the rich in dietary fibre residue that remains after the aqueous extraction of oil for the preparation of health-promoting food products (e.g. bakery products, breakfast cereals, dairy desserts, sesame or peanut paste). To this direction, the residue was dehydrated and comminuted into two powders with different particle size that were then incorporated into the structure of yellow layer cakes at various wheat flour-substitution levels (up to 30%) and their impact on selected cake batter properties as well as the nutritional, textural, microstructural, thermal and sensory properties and the ageing behaviour of the final products, were evaluated. Partial supplementation of the wheat flour by the dietary fibre-enriched powders had only a limited effect on some of the cakes’ characteristics mainly induced by protein and starch dilution as well as limited starch gelatinization, but, generally, their sensory quality was not negatively influenced, suggesting the use of both powders as a health-beneficial and inexpensive ingredient for the fortification of cakes with fibre.

Consumer demand for natural products and the requirement for eco-friendly processes promote development of innovative processes for flavour synthesis via biotechnology. In this direction, cultivation of selected industrial yeast strain under solid state fermentation of orange peel (OP) was studied. For this purpose, autoclave sterile OP for the elimination of d -limonene and natural microflora was evaluated with regard to yeast viability, nutrient consumption and cell ability to produce flavour active compounds. Non-sterile OP was also used to follow pros and cons of the sterilization process. Yeast cells showed better growth performance under sterilized process conditions, than under non-sterilized ones. In the first case, the enhanced de novo synthesis of “fruity” esters was demonstrated (48.7, 25.2, 9.3, 6.3 and 4.5 mg/kg of fermented OP for isoamyl acetate, ethyl dodecanoate, decanoate, octanoate and phenyl ethyl acetate, respectively, after 72 h). Yeast cells exhibited accelerated synthesis of ethyl hexanoate (154.2 mg/kg OP at 48 h). Biotransformation of naturally occurring aroma compounds by yeast may be considered in this process. The proposed process, resulting in high yields of industrially important volatile aroma esters (total of ∼250 mg/kg OP), could be applied to a sustainable biorefinery for the valorization of OP waste .

The influence of egg yolk (EY) or yolk plasma addition on the rheological properties and flavour characteristics of heat-set gels based on whey protein isolate (WPI) was the objective of this study. Large deformation compression tests and small deformation oscillatory measurements have shown that WPI gel structure-strengthening may take place following the incorporation of either EY or yolk plasma, indicating a possible synergistic effect between the yolk constituents on one hand and those of WPI on the other. Headspace solid-phase microextraction technique, coupled to gas chromatography–mass spectrometry (GC–MS) analysis, was applied to characterise the volatile compounds of the gels. A total of 29 compounds were identified. Furthermore, GC–Olfactometry analysis revealed that the major contributors to the overall odour quality of the mixed gels were 2,3-butanedione (buttery, caramel-like odour), hexanal (green), heptanal (fishy), 2-acetyl-1-pyrroline (cooked/milky), 1-hexanol (cooked) and methional (boiled potato-like odour), compounds originating either from WPI or EY.

Beta-pinene containing microcapsules were prepared by complex coacervation of milk proteins, i.e sodium caseinate (CN) and whey protein isolate (WPI), with carboxymethylcellulose (CMC). Milk proteins – CMC interactions were followed by ζ-potential measurements, while the initial emulsions were characterised for droplet size and biopolymer amount present at the oil/water interface. Response surface methodology was applied to investigate the effects of encapsulation processing variables, including protein/polysaccharide (pr/pl) ratio and volatile compound's mass, on encapsulation yield, loading and efficiency as well as the morphological characteristics of the produced microcapsules. The obtained results revealed that it was possible to encapsulate β-pinene with milk proteins and CMC by complex coacervation, while most of the characteristics evaluated were affected by the process variables. Coacervates prepared at the highest pr/pl ratio of 6.99 and β-pinene mass (6.99 g) were the most effective in encapsulating the flavour compound, something that was more evident in the case of WPI–CMC mixture. Additionally, microcapsule structure, evaluated by Scanning Electron Microscopy analysis, was noticeably affected by the protein/polysaccharide ratio being compact when pr/pl was low and “spongy”-like when it was high.

Seven commercial white wine samples of the Malagousia cultivar were investigated for the first time with regard to their phenolic composition and radical scavenging activity. Total phenol content, corrected for ascorbic acid contribution (0–47 mg gallic acid equivalents/L of wine), ranged between 241 and 336 mg gallic acid equivalents/L of wine. On the other hand, the range for total hydroxycinnamates was 51.5–122.4 mg chlorogenic acid equivalents/L of wine and that for total flavanols 19.6–68.8 mg catechin equivalents/L wine. Fifteen phenolic compounds were identified and quantified by gas chromatography/mass spectrometry in the selective ion monitoring and high-performance liquid chromatography coupled with diode array detector. Tyrosol, caftaric, caffeic and 2-S-glutathionyl caffeoyl tartaric (GRP) acids were the major phenolics in all samples with mean concentrations of 12.32, 10.71, 10.17 and 4.79 mg/L wine, respectively. Catechin (3.75 mg/L) and p -coumaric acid (3.04 mg/L) followed in abundance. Variations in the values of GRP/caftaric (0.1–4.6) and caffeic/caftaric (0.4–4.2) acid concentrations, suggested differences in the degree of oxidation on one hand and hydrolytic processes during production and bottling on the other. Despite these variations, the radical scavenging activity of samples examined with DPPH and ABTS + assays (mean value 0.85 and 3.45 mmol Trolox equivalents/L of wine) indicated a high efficiency in comparison to literature data on native and foreign white wines. The present findings can be useful for both technological and nutritional purposes.

In this work the development of a dressing-type emulsion powder with instant characteristics was attempted. Two dehydration methods (oven-drying and nano spray drying) were evaluated using maltodextrin in admixture with carboxymethyl cellulose or gum Arabic as coating materials. Droplet size distribution of the initial emulsions was first considered, while the resulting powders were analysed for moisture, total and free oil content, oil encapsulation efficiency, morphological characteristics, physical and flow properties and reconstitution behaviour. The results showed that particles of irregular shape, micron size, high free oil content and low encapsulation efficiency were obtained through oven-drying, while nano spray drying led to spherical, of smaller average diameter powder particles along with lower “free” oil content and higher encapsulation efficiency. Regarding their handling properties, all powders were very cohesive with poor flowability. Dehydration method significantly affected both bulk and reconstitution properties with the spray-dried powders exhibiting lower bulk and tapped density, higher dispersibility and satisfactory wettability, all related to their instantaneous character. This powdered dressing-type emulsion can be used as it is by sprinkling directly on vegetable salads and other food or by dispersing in water.

Electrostatic gelation under benign conditions of mixed whey protein isolate–carboxymethylcellulose aqueous solutions of relatively low biopolymer concentration was effected following pH reduction from neutral to values between the protein pI and the polysaccharide pK. Small deformation dynamic rheometry (time and frequency sweep measurements) was applied to determine the gel point and characterize the gel structure. State diagrams of biopolymer solutions in absence or presence of Tween 40 were also constructed to assess the contribution of interactions other than ionic ones to the development of the mixed gel structure. The findings are discussed in terms of the attainment of a stoichiometric electrical charge equivalence as the pH was moved towards acidity. As a consequence, the biopolymer molecules carried equal but opposite charges and protein–polysaccharide interactions took place. Retention of selected orange aroma compounds as a result of gel matrix formation was also investigated by applying the Headspace Solid Phase Microextraction technique, followed by gas chromatography–mass spectrometry analysis. The measurements indicated that a number of terpenic constituents of the orange oil were better retained in the matrix while the same was not observed in the case of the aldehydes.

The dynamics of orange pulp (OP) as a fermentation feedstock for the production of volatile esters of “fruity” aroma by using a commercial wine yeast strain (Saccharomyces cerevisiae var. cerevisiae) was investigated. To achieve this goal, the kinetic behaviour of yeast (cell growth, substrate assimilation and volatile ester formation) was studied in OP complemented with nutritive medium under two different aeration conditions. The results were compared with those obtained from conventional processes in nutritive medium containing glucose as a sole carbon source. The results obtained revealed that the yeast cells were able to grow in the OP-containing medium after a 12-h lag period, probably due to the inhibitory effect of limonene. OP was found to stimulate the de novo synthesis of isoamyl acetate, phenylethyl acetate and ethyl esters (hexanoate, octanoate, decanoate and dodecanoate) by S. cerevisiae. This was strongly evident in the case of limited oxygen supply. Based on the above findings, OP appears to be a promising choice for bioflavour production by yeast.

The influence of lupin protein isolate (LPI) on the volatile fraction of wheat flour (WF) bread was investigated. Headspace solid-phase microextraction technique (HS-SPME) coupled to the gas chromatography–mass spectrometry (GC–MS) analysis was applied to characterise volatile compounds of both crust and crumb. In a preliminary sensory experiment, LPI was found to have a modifying effect on the odour of WF-bread. The most important odorants of WF and LPI-containing wheat flour (LWF) breads were evaluated on the basis of detection frequency analysis. Fifty three compounds were detected by more than five judges, ten of which were detected only in LWF bread. The most important compounds of LPI-containing crumb and crust were vinylpyrazine, hexanal, 2-propylpyrazine, 2-octenal, 2,3-butanedione, 2,5-dimethylpyrazine, non-identified compounds with green, mushroom-like or pleasant odour and pyrazines. Their presence was attributed either to oxidative degradation of fatty acids or thermal reactions. Most of these compounds contributed to the aroma character of LPI-bread with green, earthy, malty, buttery and roasted notes.

Migration of potentially toxic substances from plastic packaging materials is very important in the food industry since it determines the suitability of polymers when used in food packaging. In this work, results are presented on the migration of styrene monomer from plastic packaging based on either rigid or foamed polystyrene. Water, ethanol/water solution and isooctane (resembling oil) were considered as food simulants. Experiments were carried out at various temperatures and migration was tested from 30 min to 30 days. Measurements were carried out using gas chromatography with external calibration and styrene standard solutions. No styrene was measured in water, except at high temperatures and long time periods, while the amount in ethanol/water was always grater than that in isooctane. Finally, the styrene diffusion coefficients for all the various experimental conditions were estimated using a rigorous model based on the Fick diffusion equation and thepartitioningofthemonomerbetweenthetwophasesandconsequentlytheactivationenergyofthemigrationprocesswas evaluated. c � 2011 Society of Chemical Industry

The effect of commercial tannin extracts, extracted either from grape seeds or grape skins, a natural wine polysaccharide extract, pectin and arabinogalactan on the headspace release of selected aroma compounds from a “model wine” solution was investigated. Changes in the volatility of the aroma compounds were studied using headspace solid-phase microextraction combined with GC/FID. The performance of four commercially available fibre coatings was checked and the 50/30 μm DVB/CAR/PDMS one was proved to be the most effective. A short sampling time (1 min) was used to determine the “true” headspace concentration at equilibrium between the headspace and the sample. In general, the volatility of the studied aroma compounds appeared to be correlated to increasing tannin levels as well as to their origin. The volatility of esters was generally increased upon tannin addition at low concentrations, while at higher addition levels the two extracts exhibited dissimilar behaviour attributed to their different composition. Both arabinogalactan and pectin addition at low concentrations increased the volatility of the studied aroma compounds, while at higher concentrations pectin exhibited a different behaviour by salting out hydrophobic compounds in the vapour phase. In addition, grape skin and seed tannin extracts in admixture with polysaccharides either prevented the macromolecular chains to associate with volatile molecules or led to additional flavour retention depending on the aroma compound and the addition level. Saliva addition enhanced the volatility of the most hydrophobic compounds whereas the hydrophilic compounds were retained into the matrix.

The effect of margarine substitution by extra virgin olive oil on the quality of Madeira cakes was studied. Three cakes containing either extra virgin olive oil or extra virgin olive oil/margarine mixture or margarine were prepared. The use of extra virgin olive oil increased batter density and cake volume while decreased the weight loss (%) during baking. Texture profile analysis also showed that the replacement of margarine by extra virgin olive oil affected significantly hardness and cohesiveness of the cakes. Headspace solid phase microextraction was applied in order to analyze the aroma of the three cakes. The addition of extra virgin olive oil produced a wide range of volatile compounds, which were analyzed by gas chromatography/mass spectrometry and were originated either from extra virgin olive oil or were produced during the baking process. Hedonic sensory tests were also conducted revealing that the cake prepared with extra virgin olive oil/margarine mixture was highly appreciated by the consumers as it got scores similar to control.

The impact of addition of two lupin protein isolates (LPI), enriched either in proteins belonging to globulin (LPI G) or to albumin (LPI A) fraction, on wheat flour dough and bread characteristics was investigated. LPI addition increased the dough development time and stability plus the resistance to deformation and the extensibility of the dough. The presence of LPI proteins in dough affected bread quality in terms of volume, internal structure and texture, while extra gluten addition to the blends to compensate for wheat gluten dilution, resulting from LPI addition, led to an improvement of bread quality characteristics. Generally, the incorporation of LP isolates to wheat flour delayed bread firming. The results obtained are discussed in terms of a possible action of LPI particles as a filler of the gluten network and partly in terms of possible interactions that take place between the gluten protein constituents and those of lupin.

The purpose of this work was to study the impact of the structure and composition of hydroalcoholic emulsions on the air–liquid partition of aroma compounds of the essential oil of Pistacia lentiscus var. chia, commonly known as mastic gum oil (mainly consists of terpenes). Oil-in-water emulsions (φ = 0.17), containing 15% (v/v) ethanol, stabilized by three different emulsifiers (sodium caseinate, whey protein isolate and Tween 40), were prepared by using two different lipid phases (sunflower oil and anhydrous butter fat). The homogenization conditions were varied to obtain emulsions with different volume–surface mean diameters. The partition of the volatile compounds between air phase and emulsions at three different temperatures (25, 37 and 50 °C) was monitored by applying the Headspace Solid Phase Microextraction technique, followed by gas chromatography–mass spectrometry (GC–MS) analysis. In general, the results obtained showed that sodium caseinate was the most effective in retaining mastic aroma compounds, while WPI was the least effective. This could partly be explained by the different structure of the two proteins which, when adsorbed at the interface, form a membrane that acts as a barrier and influences the partition of the aroma compounds between the air and the liquid. At the same time interactions of aroma compounds with the two proteins in the bulk phase may also play a role. The retention of the aroma compounds depended on the oil droplet size only in the case of sodium caseinate containing emulsions at 37 and 50 °C. This behaviour could be due to the substantial increase in the thickness of the adsorbed casein layer when moving from a fine sized emulsion to one with a much larger size as well as to differences in the ratio of free to adsorbed emulsifier. The composition of the lipid phase also appeared to have a significant impact on the concentration of volatile compounds in the headspace of mastic gum oil containing emulsions stabilized by proteins. This was lower in the case of butter fat probably due to differences in composition with regard to fatty acid degree of saturation as well as to volatile absorption by the liquid lipid at 40 °C and subsequent entrapment in the semisolid fat at 25 °C.

The partitioning and release of limonene and trans -2-hexenal from oil-in-water emulsions was evaluated by applying static headspace gas chromatography. Experiments were carried out on gum arabic/xanthan (GA/X) and egg yolk/xanthan (EY/X)-stabilized emulsions. The dispersed phase ( φ 0 = 0.05 and 0.20) was composed of sunflower oil, while the oil droplet size ( d 32 ) ranged from 0.8 to 12.5 μm. The type of emulsifying/stabilizing system influenced the thermodynamic component, as expressed by the air–liquid partition coefficient ( K a/l ) values at equilibrium (37 °C), of the release of limonene only. Increase in lipid fraction decreased the release of both aroma compounds. The oil droplet size had no significant impact on the partition coefficients of trans -2-hexenal, whereas for a lipid content of 20% (v/v) and GA/X stabilizing system, the partition coefficient of limonene was considerably reduced. Additionally, information on the aroma compound diffusion through the liquid–gas interface was obtained by calculating the initial slopes of the time–release curves. Both aroma compounds diffused more slowly through the GA/X-stabilized emulsions compared to EY/X-stabilized systems, while the release rate of limonene was significantly decreased when oil droplet size was increased. This behaviour was attributed to changes in viscosity as well as to reinforcement of xanthan network because of the presence of gum arabic. On the other hand, the nature of the interfacial film and the extent of oil droplet interactions in the EY/X-stabilized emulsions is considered to be responsible for their lower ability to retain the two aroma compounds. Odour assessment experiments were also conducted and the results were found to partially correlate with gas chromatographic results.

This chapter reviews the traditional Greek product Chios Mastic Gum or Mastiha, primarily known for its distinctive flavor. This is the dried exudate of the shrub-like tree Pistacia lentiscus L. var. chia of the Anacardiaceae family, cultivated exclusively in the south of the Greek island Chios. Emphasis is given on its chemistry and physicochemical properties, health effects, antioxidant and antimicrobial properties. The preparation of traditional food products based on mastic gum or essential oil, such as chewing gum, confectionery, bakery products as well as alcoholic and nonalcoholic beverages, is also discussed.

Summary The lipid and cholesterol contents of freeze- and spray-dried egg-yolk were substantially reduced by extraction with 1% polyoxyethylene (20) sorbitan mono-oleate (polysorbate 80) in 10/90, 20/80, 50/50 and 80/20 (v/v) ethanol/water mixtures. the functionally important phospholipid content of the resulting yolk-protein concentrate was only marginally reduced when low ratio mixtures were used, but total yields were reduced. the influence of polysorbate 80 is attributed to the weakening of protein-protein bonds responsible for the stabilization of egg lipoprotein structures and subsequent release of lipids.

The effect of incorporation of emulsified oil with yolk on the strength of gel network systems, produced by heating of egg yolk or egg white dispersions, was investigated. The yolk gels exhibited a decrease in their mechanical strength as a result of oil incorporation. The white-based gels, on the other hand, showed a higher strength, following incorporation of oil droplets, the result depending on the droplet size but more on oil levels. The interaction between the globular proteins of egg white and the lipoprotein-covered oil droplet surfaces was established by applying SDS-PAGE electrophoresis. The results are discussed in terms of the differences in structure between the yolk and the white proteins that may affect the way they denature and interact following heating.