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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.

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 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.

Industrial scale-up of whey fermentation, promoted by raisin extracts, using free kefir-yeast cells is reported. The fermented whey would be exploited as raw material to produce kefir-like whey-based drinks, potable and fuel alcohol, as well as kefir-yeast biomass for use as baker's yeast. The scale-up process involved the development of a technology transfer scheme from lab-scale experiments to a successive series of increased capacity bioreactors (100, 3000 and 11,000 L). The development of this technology was supported by the six-fold promotion of whey fermentation by the addition of 1% black raisin extracts (optimum concentration found in this investigation), as well as by the formation of kefir-yeast in the form of easily precipitated granular biomass that led to the avoidance of centrifugal separators, which are equipment of high cost. A cost analysis showed a big reduction of the production cost of the aforementioned products in comparison with the market prices, attributed to the negligible cost of raw materials (whey) and the granular biomass formation.

The effect of rosemary extract, chitosan and α-tocopherol, added individually or in combination, on lipid oxidation and colour stability of frozen (-18°C) beef burgers stored for 180 days was investigated. The burgers' lipid oxidation and appearance were evaluated through measurement of primary (conjugated dienes and peroxide value) and secondary (malondialdehyde) oxidation products, together with visual assessment and instrumental measurement of colour. Chitosan alone and in combination with either rosemary or α-tocopherol had the best antioxidative effect (P⩽0.05) compared to individual use of rosemary or α-tocopherol, while the best results were obtained with the combination of chitosan and rosemary. The differences of antioxidative effects, however, between individual use of rosemary or α-tocopherol as compared to the controls were also significant (P⩽0.05). Chitosan added individually or in combination with either rosemary or α-tocopherol had also a noteworthy effect on the burgers' appearance as it contributed to red colour retention for a much longer period (P⩽0.05) compared all other treatments and the controls. In conclusion, the best antioxidative effects were obtained with the combination of chitosan and rosemary extract.

The effect of ethanol and acetone extracts obtained from Greek sage (Salvia fruticosa) and summer savory (Satureja hortensis L.) on the thermal stability of vegetable oils heated at frying temperature (180 °C) was studied. Virgin olive oil (VOO), refined olive oil (ROO), sunflower oil (SO), and a commercial oil blend suitable for frying (BL), enriched with each extract obtained from the two plant materials at a concentration of 3 g/kg oil, were heated at 180 °C for 10 h. Changes during heating were assessed by quantification of total polar materials and determination of p-anisidine values. The acetone extract obtained from Greek sage showed a better inhibitory effect against thermal oxidation of heated refined oils (BL, ROO, SO) than the respective ethanol extract, although the latter was found to have a relatively higher total phenol content. Both summer savory extracts effectively retarded the thermal oxidation reactions during oil heating, showing a more pronounced effect than the Greek sage acetone extract. The activity of the acetone extract obtained from summer savory was stronger (SO, BL) or similar (ROO, VOO) to that of the summer savory ethanol extract, although the latter was found to have a higher total phenol content.

Partitioning and release of limonene and trans −2-hexenal from polysaccharide solutions was studied by applying static headspace gas chromatography. Experiments were carried out on xanthan/propylene glycol alginate and xanthan/gum arabic solutions at various concentrations. Changes in the polysaccharide matrix exhibited a considerable effect on the thermodynamic component as expressed by the air/liquid partition coefficient ( K a/l ) values at equilibrium (37 °C). Viscosity increase was shown to affect the initial release rate, as this is defined by the amount of limonene and trans -2-hexenal released over the first few minutes of the experiments. The physicochemical properties of both aroma compounds, especially their hydrophobicity, were also of importance in air/liquid partition, with limonene to be mostly affected by polysaccharide addition.

The development of a novel whey-based beverage with acceptable organoleptic properties is reported, where various treatments were studied. Kefir yeast immobilized on delignified cellulosic materials (DCM) or gluten pellets proved to accelerate whey fermentation significantly, with the latter support being not so preferable. Kefir granules seemed to achieve similar fermentation times as DCM. The final pH of the product is suggested to be 4.1 since the profile of the volatile byproducts was higher than other pH values tested. The addition of fructose seemed to be beneficial on the volatile content of the product, although its acceptability as determined by a preference panel was similar to that of the control. Finally, black raisin extract appeared to promote fermentation without any positive effect on the preference of the evaluators.

A kefir-type drink was prepared by fermentation with kefir granules of cheese whey containing fructose and black raisin extract. Milk (20%) was then added to improve its rheological and sensory properties and in order to prevent casein coagulation and sedimentation in the acid environment of the mixture, a number of polysaccharides were evaluated as stabilizers. Xanthan appears to be more effective at relatively low concentration levels (0.2%) compared to guar gum while high methoxyl pectin, a well-known acid milk drink stabilizer was less effective in this respect even at concentrations as high as 1%. Particle size and rheology measurements pointed out to the importance of the weak gel properties of xanthan solution in stabilizing the system against ‘wheying off’ while other stabilization mechanisms such as particle network formation as a result of depletion flocculation in the case of guar gum or pectin adsorption at the casein particle surface resulting in steric stabilization appear to be less dominant.

The overall quality of virgin olive oil (VOO) is closely related to its oxidative stability that is usually evaluated through the stability index measured by the Rancimat apparatus. Quality characteristics and also pro-oxidant and antioxidant content for 52 Greek VOO samples (Koroneiki cv) were used to build up a model capable of predicting stability. Collinearity diagnostics, variable selection, and regression analysis were applied to the experimental data to locate the contribution of each parameter to the keeping quality of the samples. The predictive ability of the model was confirmed for a second VOO sample set of the same cultivar. It was found that except for the peroxide value, which negatively influences the stability, other important parameters were α-tocopherol, total polar phenol and total chlorophyll content. It is concluded that the colorimetric determination of total polar phenols, the spectrometric determination of total chlorophylls and the high-performance liquid chromatography analysis of α-tocopherol, not presently included in the established methods of official analysis, can be used for a better evaluation of VOO quality. These parameters, which can be easily adopted as routine methods by the industry, seem to be of utmost importance for shelf life prediction and expiration dating if applied for the promotion of the most competitive products in the international olive oil market.

Single cell protein (SCP) was produced by aerobic fermentation of cheese whey by kefir microorganisms. A feed-batch system was developed on a bioreactor of 4 1. The experiments were conducted under controlled pH (5.5) and temperature (30 °C) conditions. The biomass was analyzed for protein, lipids, carbohydrates and ash and its functional properties (emulsification, foaming, gelation) were studied. Single cell protein (53.9% protein) exhibited emulsifying properties similar to those of defatted soy flour, while its Ibaming activity and foam liquid stability were much higher. Finally, texture profile analysis of gels, formed by heating water dispersions of SCP, showed that the structures produced were stronger compared with those of gels made with soy flour.

A large number of virgin olive oil samples obtained from different areas in Greece were analyzed for various quality parameters. The work focuses on the colorimetric determination of total phenols with the Folin-Ciocalteu reagent and its importance in predicting shelf life of virgin olive oil. The results indicate a good correlation of total polar phenol content with the stability of the oil. Colorimetric determination of ortho-diphenol content does not seem to be a better means for predicting virgin olive oil stability. RP-HPLC quantification of hydroxytyrosol and tyrosol in their free form gives poor results in the case of freshly extracted oils. It is concluded that until an easy-to-manage HPLC method will be available, which will quantify accurately both free and bound forms of hydroxytyrosol and other phenolics, the colorimetric method for the determination of total polar phenols remains a good practical means to evaluate the stability of virgin olive oil.

Unprocessed olives are well-known sources of phenolic antioxidants with important biological properties. Processing methods to prepare table olives may cause a reduction of valuable phenols and may deprive the food of precious biological functions. The present work was undertaken to evaluate table olives produced in Greece as sources of biophenols. Commercially available olives were analyzed for their total phenol content by using the Folin-Ciocalteu reagent and for individual phenols by RP-HPLC. Samples were Spanish-style green olives in brine, Greek-style naturally black olives in brine, and Kalamata olives in brine. Most of the types of olives analyzed were found to be good sources of phenols. Hydroxytyrosol, tyrosol, and luteolin were the prevailing phenols in almost all of the samples examined. High levels of hydroxytyrosol were determined mainly in Kalamata olives and Spanish-style green olives, cultivar Chalkidiki (250-760 mg/kg).

The effect of rosemary extract, chitosan and α-tocopherol, added individually or in combination, on microbiological parameters and lipid oxidation of fresh pork sausages stored for 20 days at 4 °C was investigated. Microbiological determinations included the enumeration of Enterobacteriaceae , Pseudomonas spp., total viable count, yeasts and moulds and lactic acid bacteria, while pH values were also determined. Lipid oxidation was evaluated through measurement of primary (peroxide value) and secondary (malondialdehyde concentration) oxidation products. Chitosan addition resulted in significant ( P ⩽ 0.05) inhibition of microbial growth, while the lowest microbial counts were obtained in the samples containing both chitosan and rosemary, indicating a possible synergistic effect. Chitosan and its combinations with either α-tocopherol or rosemary, and especially the latter combination, showed also the most intense antioxidative effect ( P ⩽ 0.05), at least when compared to α-tocopherol alone or the controls, while use of rosemary extract alone had a comparable ( P > 0.05) antioxidative effect with chitosan and its combinations. Shelf life of samples containing chitosan was almost doubled compared to the remaining samples. In conclusion, the best antimicrobial and antioxidative effects were obtained from the combination of chitosan with the rosemary extract.

A three-step process to scale-up kefir biomass production at a semi-industrial scale employing whey is reported. Aerobic fermentations were initially performed at laboratory scales, in 1.5- and 4-L bioreactors, yielding 79 g/L final kefir biomass (0.89 g/g of lactose utilized), in 7 h of fermentation time. The use of whey as carbon source even in solid cultures led to the formation of a granular biomass. These results encouraged scale-up at a semi-industrial-scale pilot plant employing 100- and 3,000-L bioreactors, leading to the development of a process for granular kefir biomass production. The results validated the laboratory-scale experiments and the avoidance of centrifugal separators due to granular biomass formation. Pilot-plant operations showed kefir to be highly resistant to contamination under actual industrial conditions and no serious problems in handling of raw materials and equipment were observed. Economic analysis showed a 20% higher cost of the market price of products, with added value of up to 15.9 x 10 9 ? within the European Union.

Essential oils and extracts of aromatic herbs obtained by organic solvents have been extensively studied for their antioxidant activity in lipid substrates. Very little is known about the possible presence of antioxidants in polar extracts from herbs used in preparation of infusions and decoctions. In this work water extracts of six different herbs of the Lamiaceae family (dittany, lemon balm, mint, sage, sideritis and sweet marjoram) were prepared. The extracts were examined for their effect against lipid oxidation in comparison to a tea water extract. Sweet marjoram, sage and dittany extracts were found to have a remarkable capacity in retarding lipid oxidation. Examination by thin-layer chromatography of the freeze-dried extracts, before and after hydrolysis, showed that the extracts were rich in bound forms of phenolic compounds such as hydroxycinnamic acids and flavonoids. Rosmarinic and caffeic acids were detected in all extracts with the exception of those from mint and sideritis. These results indicate that certain plants used for the preparation of infusions could be further studied like tea as sources of antioxidants.

Publisher Summary Foods and biopolymers are very closely related because proteins and polysaccharides, as the widespread macromolecules existing in nature, belong to the main naturally occurring food components or constitute important food ingredients and additives. The food sector has one of the highest numbers of legislations, leaving very little room for development of specification. As a principle, most of the safety aspects regarding foods and their ingredients are covered by food legislation. Although food legislation exists on the excuse of consumers' health protection, it often becomes a masked intervention to international trade. Traditionally, National Food Codexes were composed of rules developed around the need (1) to protect consumers' health, (2) to protect consumers' economic interests against fraud, (3) to assure foods' nutritional value, and (4) to give competitive advantage to local raw materials or to local food industry. Rules related to protect consumers' health should be based on scientific grounds and set limits that provide sufficient health protection. Rules to protect consumers' economic interests against fraud are usually relating product denomination with compositional rules. Rules related to assure foods' nutritional value include those controlling the possible fortification of foods by minerals, vitamins, or essential amino acids and fatty acids or the nutritional labeling of food. Rules to give competitive advantage to local raw materials or to the local food industry are gradually abandoned as they are considered as barriers to free trade.

Minor constituents of virgin olive oil are important for the remarkable stability of the oil in autoxidation, but the exact role and the extent to which each antioxidant factor contributes to the total antioxidant effect has not been thoroughly Investigated. In this study the role of α-tocopherol is explored at various acidity levels and at low concentrations of ortho-diphenols. A substrate of olive oil triacylglycerols devoid of prooxidant or antioxidant constituents was prepared from refined olive oil by column chromatography To tills substrate, slightly oxidized, the additives (oleic acid, 3,4-dihydroxyphenylacetic acid and α-tocopherol) were added and the stability was assessed by periodical measurements of peroxide values. It was found that free fatty adds reduce mainly the protective activity of the ortho-diphenol. It is also concluded that α-tocopherol has a synergistic effect with the ortho-diphenols and contributes significantly to the retardation of peroxide formation. This is Important for oils poor in ortho-diphenols.Los constituyentes menores del aceite de oliva virgen son importantes para la notable estabilidad del aceite en la autooxidación, pero el papel exacto y el alcance con que cada factor antioxidante contribuye al efecto antioxidante total no ha sido investigado a fondo. En este estudio el papel del α-tocoferol es examinado a varios niveles de acidez y a baja concentraciones de o-difenoles. Un sustrato de triacilgliceroles de aceite de oliva desprovisto de constituyentes prooxidantes o antioxidantes fue preparado a partir de aceite de oliva refinado mediante cromatografía en columna. A este sustrato, un poco oxidado, los aditivos (ácido oleico, ácido 3,4-dihidroxifenilacético y α-tocoferol) fueron añadidos y la estabilidad fue calculada mediante medidas periódicas del índice de peróxido. Se encontró que los ácidos grasos libres reducen principalmente la actividad protectora de los orto-difenoles. Se concluyó también que el α-tocoferol tiene un efecto sinergista con los orto-difenoles y contribuye significativamente al retraso de la formación de peróxidos. Esto es importante para los aceites pobres en orto-difenoles.

The potent odorants of two Greek virgin olive olis differing in flavor were evaluated by aroma extract dilution analysis (AEDA) and quantitated by stable isotope dilution assay (SIDA). The odor activity values (OAVs) of these potent odorants were calculated by dividing their concentrations in the oil samples by the corresponding flavor threshold values, as an approach to objectify the flavor differences of the olive oils. Compounds which mainly contributed to several flavor notes were: hexanal and (Z)-3-hexenal (green), octanal, (Z)-2-nonenal, (E,E)-2,4-decadienal and 1-octen-3-one (rancid), ethyl 2-methyl-butanoate, ethyl 2-methylpropanoate and ethyl cyclohexanoate (fruity).

A triacylglycerol mixture containing 5% stigmasterol by weight and devoid of other unsaponifiables was heated at 180 ± 5°C for several hours. Oxidation products from stigmasterol were separated and isolated by column chromatography and preparative thin-layer chromatography. Characterization of individual compounds was based on chromatographic mobilities, specific colour reactions, UV and IR spectroscopy and fragmentation patterns from the mass spectra of the purified oxidation products. A hydrocarbon (stigmasta-3,5,22-triene), a triunsaturated ketosteroid (stigmasta-3,5,22-trien-7-one), a diunsaturated ketosteroid (stigmasta-4,22-dien-3-one) and a pregnane derivative ( Δ 5 -pregnen-3 β -ol-2-one) were identified. There is also evidence for the presence of more polar compounds such as hydroxy and epoxy derivatives.