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A kinetic study of the phenolic compounds extraction from the solid residue remaining after the hydro-distillation of oregano (Origanum vulgare ssp. hirtum) was performed. Ethanol-in-water mixtures were used for the extraction and the effect of ethanol concentration, solid particle size, solid-to-liquid ratio, and temperature was examined. The experimental data were adequately fitted by both Peleg’s model and Fick’s law considering two stages of extraction, a high-rate initial one (up to 30 min), followed by a slower stage. The higher rate of phenolic compounds extraction was obtained with 60%, v/v ethanol. Increase in temperature from 22 °C to 60 °C, decrease in particle size (from >1000 μm to The HPLC analysis indicated mainly the presence of rosmarinic acid, lithospermic acid, flavonoid glycosides and carvacrol. The 60% ethanol as solvent exhibited the highest phenolics recovery and the strongest antiradical capacity. Increase in temperature from 22 °C to 60 °C led to improvement of both time and efficiency of the extraction performed with pure ethanol.

Background Lipid oxidation is one of the main causes of food spoilage. It can be delayed by the addition of antioxidants to food or by using vacuum or modified atmosphere packaging. A recent approach is the application of antioxidants in active packaging. Scope and approach The scope of this review is to present and update all information about the incorporation of natural antioxidants in edible and active films and coatings. Natural antioxidants can replace chemical additives and are preferably accepted by the consumers. Their effect on the barrier, mechanical and antioxidant properties of the various films (chitosan, cellulose derivatives gelatin etc.) are discussed. The ability to delay food oxidation is examined in relation to the active components. Key findings and conclusions Water or ethanol extracts from several herbs (rosemary, oregano, tea), berries, or plant by-products increased the total phenolic content and the antiradical activity of the films and proved efficient in delaying the oxidation of fish and meat products. Also, a protective activity was observed from the essential oils that were rich in carvacrol or thymol. The barrier properties of the films were positively affected, due to interactions between the active groups of the additive (e.g. polyphenols) and the film matrix. On the contrary, hydrophilic additives increased water vapor and oxygen permeability. The mechanical properties were in most cases adversely affected. Results are promising and further research on the release of antioxidant compound into food, the effect on sensorial properties, and application to other lipid foods may encourage practical application.

Sunflower oil-in-water emulsions were enriched with two Satureja thymbra extracts - obtained by ethyl acetate (EAcs) or ethanol (Es), rosmarinic acid (RA), or quercetin (Que), and the effect of storage temperature (5–40 °C) on the emulsions’ phenolic content and oxidative stability was studied. HPLC analysis of the extracts indicated RA as the main component. The phenolic content of the emulsions decreased during storage, following first-order kinetics, with a temperature-dependent rate. RA was the main compound that decreased, Que followed a slower decrease and the rest flavonoids remained almost constant. The additives protected the emulsion against oxidation according to the order Es > Que > EAcs > RA. The protection factor ranged from 73 to 81% at 5 °C, but decreased to around 53% for Que and Es, 33% for EAcs, and 22% for RA at 40 °C. Emulsions enriched with extracts from S. thymbra retain their phenolic content and oxidative stability at refrigeration temperatures.

The encapsulation of oregano essential oil in yeast cells was studied. Untreated cells, cells autolyzed for 8 and 24 h at 52 °C, cells treated with Pulsed Electric Fields at three different energy inputs (3.2, 13.6 and 107 kJ/kg) and cells treated with High Pressure Homogenization at 800 bar/4 passes were comparatively assessed. Encapsulation was performed by incubating the cell materials in contact with the oil at temperatures 30, 37, 45 and 65 °C for up to 48 h. Apart from homogenization, none of the other cell pretreatments affected the final encapsulation load at the temperatures studied. All pretreatments had a significant effect on the encapsulation kinetics, leading to increased encapsulation rates compared to the untreated sample. The essential oil release from the obtained capsules was found to depend on water activity and became significant above aw = 0.7, with cell pretreatments increasing the released oil percentage at higher water activities.

The effectiveness of Satureja thymbra (L.) extracts as potential antimicrobial or antioxidant agents in fish coating was studied. Dried leaves of the plant were subjected to steam distillation to recover the essential oil (EO). The solid residue was extracted successively with ethyl acetate and ethanol to recover the phenolic compounds. γ-Terpinene and carvacrol were the main components of EO, according to GC–MS analysis. LC–DAD–MS analysis of the extracts showed the presence of four main flavonoids and their derivatives in ethyl acetate, while rosmarinic and salvianolic acid A predominated in ethanol extract. The EO, ethyl acetate extract (EAcs), ethanol extract (Es), and their combinations were used in edible films to prolong the shelf life of fresh gilthead seabream (Sparus aurata) fillets. CMC solutions enriched with the extracts were prepared, the sliced fish fillets were soaked for 5 min in the solutions, packed aerobically, and stored at 0 °C. Microbial growth and oxidative deterioration was estimated. EO used alone showed a moderate antimicrobial and antioxidant protection. The EAcs and EAcs-EO combination showed the best antimicrobial effect, resulting in 25 and 35% shelf life extension, while the Es and Es-EO combination the best antioxidant activity, reducing the peroxide values by approximately threefold and eliminating the formation of secondary oxidation products.

Copigmentation of anthocyanins accounts for over 30% of fresh red wine color, while during storage, the color of polymeric pigments formed between anthocyanins and proanthocyanidins predominates. Rosmarinic acid and natural extracts rich in hydroxycinnamic acids, obtained from aromatic plants (Origanum vulgare and Satureja thymbra), were examined as cofactors to fresh Merlot wine and the effect on anthocyanin copigmentation and wine color was studied during storage for 6months. An increase of the copigmented anthocyanins that enhanced color intensity by 15-50% was observed, confirming the ability of complex hydroxycinnamates to form copigments. The samples with added cofactors retained higher percentages of copigmented anthocyanins and higher color intensity, compared to the control wine, up to 3 months. However, the change in the equilibrium between monomeric and copigmented anthocyanins that was induced by added cofactors, did not affect the rate of polymerization reactions during storage.

Industrial tomato processing by-products are intended mainly for animal feed or fertilizer, though they can be used for the recovery of valuable constituents. Carotenoids constitute an important component of these by-products, well credited with important health-promoting functions. This study examined the effect of several organic solvents (hexane, ethanol, acetone, ethyl acetate, ethyl lactate and their mixtures), and extraction temperature on the recovery and isomerization of carotenoids from tomato processing by-products. Another area under investigation was the stability of carotenoids, as affected by drying and storage conditions of tomato by-products. HPLC–DAD analysis was applied for the efficient separation and analysis of the carotenoids and their cis-isomers. The highest extraction yield was obtained with ethyl lactate (203.6 μg/g dry by-product) followed by hexane–ethyl acetate mixture with a considerably lower yield (36.1 μg/g dry by-product). The identified carotenoids in all solvent extracts followed the order: lycopene ≫ β-carotene > lutein, in their predominant trans-configuration. Among the identified isomers, 5-cis lycopene and 15-cis-β-carotene were the most abundant in all extracts. The increase of extraction temperature increased the total lycopene concentration in all extracts, whereas cis-isomers remained lower than 8 % in most solvents. A steadily high percentage of cis-isomer (≈30 %) was observed in ethyl lactate extracts, independent of temperature. Conversely, the increase of extraction temperature induced a reduction in total β-carotene and total lutein concentration in all solvents, while cis-isomers were not detected. Drying or even cold storage of the raw material led to decreased yields, and affected lycopene isomerization with a considerable increase of cis-isomers.

Enzyme (EA) and high pressure (HP) assisted extraction of carotenoids, especially lycopene, from tomato waste using various organic solvents was examined. Total carotenoid and lycopene extraction yields were increased by the use of pectinase and cellulase enzymes, when compared to the non enzyme treated solvent extraction process. The increase of extraction yield depended on the solvent. Maximum total carotenoid (127 mg/kg d.w.) and lycopene (89.4 mg/kg d.w.) extraction yields were obtained in enzyme treated samples extracted with ethyl lactate (solvent:solid = 10:1 mL:g), corresponding to almost 6-fold and 10-fold increase, respectively, with respect to non enzyme treated samples. HP assisted extraction led to higher extraction yields (from 2 to 64% increase depending on the solvent used) compared to conventional solvent extraction process performed at ambient pressure for 30 min. HP assisted solvent extraction was successfully performed at 700 MPa by using significantly ( P

Industrial tomato processing generates large amount of low-value by-products, primarily used as livestock feed or disposed of; however, being a rich source of natural carotenoids, tomato waste can be used to produce high value-added products for food, cosmetics, or pharmaceutical applications. The objective of this review is to summarize and give an overview of the extraction methods available for the recovery of carotenoids and, especially, lycopene from tomato processing by-products. Organic solvent extraction techniques are presented and the effect of extraction conditions on carotenoids recovery is evaluated. In particular, the use of Ultrasound Assisted (UAE), Microwave Assisted (MAE), Enzyme-Assisted (EAE) and Extraction at High Pressure (HPE) for the recovery of carotenoids is assessed. Also, this review examines the efficiency of Supercritical Fluid Extraction (SFE) and in particular the effect of process parameters on carotenoid recovery from industrial tomato waste.

Mavrokountoura, a clone of the Mandilaria grape cultivar, was studied for the first time. The morphological characteristics and composition of berries were determined, as well as total phenols and tannins in skins, flesh, and seeds. The skin anthocyanins were identified using HPLC-MS/MS and quantified using HPLC-DAD. Two main anthocyanins were identified as malvidin-3-O-glucoside and malvidin-3-O-(6″-p-coumaroyl)-glucoside. One minor anthocyanin was identified as malvidin-3-O-(6″-acetyl)-glucoside. Glycosides of delphinidin, petunidin, and peonidin were detected in traces. Young Mavrokountoura wine was also studied. Extraction of total phenols from the grape to the young wine amounted to 32%, composing mainly non-tannic phenols. The individual anthocyanin components exhibited different extractability values from the skin to wine, ranging between 10–94%.

Fat was replaced at 35% to 100% in cakes by maltodextrin (dextrose equivalent = 3), inulin (high performance and granulated), oligofructose, citrus pectin, and microparticulated protein. Fat replacement by 35% did not induce significant differences in general. Above 65% fat replacement resulted in statistically significant (P < 0.05) decreased viscosity (except for pectin) that was followed by statistically significant decrease in air incorporation and broader bubble size distribution. The starch gelatinization temperature showed a statistically significant increase when fat was replaced by fructose oligosaccharides. The cakes presented statistically significant increase of hardness, elasticity, and decrease of volume development as fat replacement increased above 65%. Also cakes with increased fat replacement received lower scores on taste and flavor, whereas at total fat replacement they were evaluated as not acceptable. Nevertheless, at 65% fat replacement, the samples presented acceptable textural, physical, and sensorial attributes.

The antioxidant activity of carotenoids (β-carotene, lycopene, paprika, marigold, bixin- and norbixin-rich annatto extracts) was estimated in sunflower oil-in-water emulsions (o/w) stabilized either by Tween 20 or by a mixture of Tween 20 and sodium caseinate at equal concentrations. Both polar (paprika, marigold, bixin, norbixin) and hydrophobic (β-carotene, lycopene) carotenoids exerted a clear antioxidant effect during thermal accelerated autoxidation (60 °C) of o/w emulsions stabilized by Tween 20, while in the protein-based emulsions only polar carotenoids acted as antioxidants against the production of primary and secondary oxidation products. Furthermore, o/w emulsions, containing different concentration of paprika and bixin-rich annatto extract (0.25–1.5 g/L) in the lipid phase oxidized slower than the control emulsions. Meanwhile, the rate of carotenoids' degradation revealed that polar carotenoids, which presented antioxidant effect in both protein and Tween 20 stabilized emulsions, presented a higher rate of degradation than the hydrophobic carotenoids.

Bulk oils and oil-in-water emulsions were subjected to high hydrostatic pressure (HHP) (200, 650 MPa) treatment so as to estimate the effect of applied pressures on lipid oxidation. HHP-treated and non-treated samples were left to autoxidise under accelerated conditions (2 weeks, 70 °C) and their oxidative status was periodically estimated by measurement of conjugated dienes and peroxide value. Total changes of thiobarbituric acid-reactive substances were recorded as additional oxidative markers for emulsions. Results showed an increase in oxidation as pressure was increased especially at 650 MPa. Lipid oxidation rates that were more pronounced for HHP-treated samples can be correlated to measured dissolved oxygen that was also higher. HHP did not seem to have an effect on emulsion droplet size. The addition of Majorana syriaca (200 ppm) ethyl acetate extract led to protection against lipid oxidation under HHP and atmospheric conditions, 20.9–38.7% and 28.9–43.2%, respectively. It was observed that the antioxidant effect of M. syriaca extract under HHP was weaker.

Summary This study evaluates the antioxidant effectiveness of a natural extract obtained from Majorana syriaca in fried and baked foods. Majorana syriaca was extracted with ethyl acetate (yield 129 g kg−1, dry basis) and the extract was added to refined corn oil at a concentration of 500 ppm. The oil was used in deep frying of potato chips at 185 °C and in making baked cookies. Potato chips and cookies were further subjected to accelerated oxidation at 70 °C. The protection of the frying oil was moderate as indicated by the polar content and conjugated dienes (CD) measurements, however, a remarkable improvement of the oxidative stability of the fried chips was observed through the decrease of peroxide value (PV) and CD by 59–72% and 51–79%, respectively, compared to samples with no additive. Also, the PV and CD of cookies decreased by 79% and 72%, respectively.

Introduction Rapid test methods are increasingly being promoted as tools for food companies to validate and/or verify the efficacy of their food-safety management systems. However, little is known about their take-up by the industry nor on what industry's current and future needs are. Objectives In order to gain further information a questionnaire-based survey was conducted in 17 countries (11 European Union members and 6 non-European Union members). The survey was designed to gain insight into routine analytical regimes operated by food industries and the role played in them by the use of rapid test methods. Methods Over 2600 questionnaires were circulated to companies covering the whole food chain and 661 replies (about 25%) were received. Results At a strategic level, the survey revealed that raw materials and final products are the most routinely analyzed samples, and that the major analytes tested for concerned (in descending order) microbiological contaminants, heavy metals, pesticides, foreign bodies, mycotoxins and allergens. With regard to the use of rapid test methods, 66% of the respondents use them, while, almost all respondents stated their interest for extending the range of tests performed. In terms of future needs, rapid tests for microbiological analysis was emphasized by most respondents, while food allergens and mycotoxins-related test kits were also of high importance. Conclusions The results obtained indicate that the food industries currently use or are well prepared for the implementation of new rapid methods of analysis. Lebesi D, Dimakou C, Alldrick AJ, Oreopoulou V (2010). Rapid test methods: a versatile tool to assist food-safety management. Quality Assurance and Safety of Crops & Foods, 2, 173–181.

The activity of natural carotenoid extracts against the autoxidative deterioration of sunflower oil-in-water emulsions was estimated in terms of primary (lipid hydroperoxides) and secondary (“off flavour” volatiles) oxidation products. At a concentration of 2 g l −1 , the tested carotenoids did not inhibit the production of hydroperoxides but they significantly retarded the formation of volatile aldehydes during the storage of simple tween-stabilised emulsions at 30 °C. In another series of experiments, several carotenoid extracts (paprika, annatto and marigold preparations) containing mainly polar carotenoids, added at an active concentration of 1 g l −1 , exerted a strong activity against hydroperoxides and TBARs during the accelerated oxidation (60 °C) of homogenised protein-based emulsions. On the contrary, carotene preparations rich in hydrophobic α- and β-carotenes and lycopene did not significantly differ from the control emulsion. Therefore, the carotenoid structure modulated their antioxidant effect, while concentration and emulsion structure may also affect carotenoid activity in protein dispersed systems.

MoniQA (Monitoring and Quality Assurance in the total food supply chain) is a Network of Excellence funded under the EU 6th Framework Programme. Its aim is to work towards the harmonization of worldwide food quality and safety monitoring and control strategies by establishing durable integration of leading research institutions, industrial partners and small and medium enterprises working in complementary fields of food quality and safety analysis. One of the main objectives of the project is to ‘develop harmonization guidelines for validation and standardization of detection methods and technologies in food safety and quality’. To achieve this, the relative importance of the range of contaminants and residues causing problems in food needed to be established. This paper outlines the methodologies adopted for prioritizing harmonization issues and identifying needs for research and development of analytical methods within the areas of natural contaminants (bio-toxins, food allergens), microbiological contaminants, chemical contaminants originating from environmental sources (heavy metals, etc.), industrial activity (dioxins, polychlorinated biphenyls, etc.) or agricultural practices (pesticides and veterinary drag residues), food additives (colourants, sweeteners, etc.), processing contaminants (acrylamide, trans fatty acids, etc.) and authenticity (cheaper substitutes, fraud, etc.). Qualitative methods are also included in the prioritized activities, as there are no internationally accepted validation protocols.

Three alternative extraction procedures were carried out in order to separate the antioxidant components and isolate an efficient extract from Origanum dictamnus . Procedure A included sequential extractions with petroleum ether (PE), diethyl ether (DE) and ethanol; procedure B sequential extractions with PE and ethyl acetate (EAc); procedure C a single step extraction with ethanol. The most efficient radical scavengers, according to the DPPH method, were isolated in ethanol extract of procedure A (mainly rosmarinic acid), followed by ethanol extract of procedure C. However, both ethanol extracts had low solubility in oil and could not protect it. EAc and DE extracts, containing mainly apigenin and epirosmanol ethyl ether, presented lower radical scavenging activity but were very effective against autoxidation of cottonseed oil (a concentration of 200 ppm was adequate to stabilize it). PE extract protected the oil effectively at concentration of 350 ppm, while being the least active against DPPH. Industrial relevance This study examines Origanum dictamnus as a potential antioxidant additive for edible oils and fats. Three different extraction procedures of the raw material with non-toxic organic solvents were used to recover the sum of the extractable compounds and specific fractions respectively. The extraction procedures, accompanied with analytical techniques, led to the characterization of the antioxidant properties and the composition of the plant as well as the isolation of very efficient oil-soluble antioxidant fractions.

HPLC-DAD coupled with mass spectrometry in the positive ionization mode was applied to study the fragmentation of twelve selected flavonoids. Compounds belonging to all the major subgroups found in common plants, i.e. flavonols, flavones, dihydroflavonols, flavanones and flavanols were studied. Compound standards were injected into the spectrometer and produced characteristic mass spectra. The fragmentation of each compound was studied and it was shown that the dehydration and carbon monoxide losses from the [M+H]+ ion by the members of each subgroup produced specific fragments, thus allowing the characterization of the flavonoid subgroups. Moreover, fragments resulting from fission of the C-rings are specific of each subgroup and revealed the substitution pattern of A- and B-rings. In order to verify the identifying efficiency of the positive ionization mode through these characteristic fragmentations, the unknown flavonoids of an Origanum vulgare diethyl ether extract were separated with the HPLC system and the major peaks were successfully identified with the mass spectrometer.

Structure—activity relationships of flavonoids against cottonseed oil oxidation are the objective of this work, which focuses on the contribution of C-ring and 5,7-di-OH A-ring. Flavonoids with a catecholic B-ring, namely quercetin, fisetin, luteolin, taxifolin, (+)-catechin and eriodictyol were added in increasing concentrations to cottonseed oil and the induced decrease in the rate constant of peroxide formation (k) and peroxide values (PV) were determined. The flavonoid depletion was monitored during the autoxidation with high-performance liquid chromatography-diode array detector (HPLC-DAD) analysis. The fully substituted C-ring was established as the most significant element for maximal antioxidant activity; quercetin even decreased k by 86% in comparison with the control and presented the highest decrease of PV per mmole of antioxidant. Flavonoids missing the 2,3-double bond or the 3-OH (taxifolin, luteolin) resulted in a smaller decrease of k, and the lack of both of the above structural elements (eriodictyol) resulted in the smallest decrease. Lack of the 4-carbonyl in the C-ring had the least negative effect on antioxidant activity since (+)-catechin presented the strongest protection after quercetin and fisetin. The activity of the latter flavonoid proved that A-ring hydroxyls, despite the unfavorable m-configuration, participate in the stabilization of the lipid substrate, although their significance was secondary.

The present paper examines whether certain processing factors may influence the oxidative stability of whey protein oil-in-water emulsions, which are structurally close to innovative industrial products (e.g. “fresh-cheese” and “non-dairy cream” types). We first checked whether the thermally induced whey protein denaturation might correlate with oxidative changes, in whey protein emulsions prepared with heat pre-treatment at varying temperatures (40–85 °C). The results showed that an increase of whey protein denaturation (in particular at >60 °C temperatures) was associated with a decrease of emulsion oxidative sensitivity, in terms of conjugated diene hydroperoxides production. In model whey protein emulsions prepared at 70 °C under varying homogenisation pressures (30–600 bars), any effect of the droplet size on the oxidative changes was subsequently investigated. The measurements of conjugated dienes or TBARs did not reveal a clear trend of changes for either of these oxidative indicators with emulsion droplet size.

Summary In this study, Origanum heracleoticum was examined as potential source of phenolic antioxidants. The components of the plant were extracted in a Soxhlet apparatus sequentially with solvents of increasing polarity, specifically with petroleum ether (P), diethyl ether (D) and ethanol (E); the ethanol extract was further fractionated to obtain a diethyl ether (ED) and an ethyl acetate (EEAc) fraction. The activity of the extracts to scavenge 2′2′-diphenyl-1-picrylhydrazyl followed the order ED > E> D > EEAc >> P. Moreover, the antioxidant activity in refined cottonseed oil at a concentration of 500 ppm was monitored through peroxide value measurements and revealed that ED resulted in the highest decrease in the rate of peroxide formation followed by D. Specific flavonoids and rosmarinic acid were detected as the main components of D, ED through HPLC–DAD and HPLC–MS/MS analyses.

The antioxidant effects of natural carotenoid extracts on the oxidation of oil-in-water emulsions (initiated by a water-soluble radical initiator at 60 °C) were spectrophotometrically assessed at 233 nm. Headspace volatiles were also monitored for selected samples. At concentration of 1 g l − 1 the tested carotenoids significantly reduced the oxidative deterioration of sunflower oil-in-water emulsions. The presence of polar groups was found to modulate the carotenoid activity. Annatto extracts (orbiting and bixin) containing carotenoids with carboxylic and esters groups, were more effective than marigold extract containing lutein (with two hydroxyl groups). β-Carotene and a tomato (lycopene-rich) extract, (un-substituted carotenes), were the least effective. For polar carotenoids, the antioxidant activity did not increase with concentration above a specific level. The tested carotenoids strongly inhibited the formation of volatile aldehydes. Mixtures of lutein or β-carotene with tocopherol isomers increased the antioxidant activity of individual carotenoids. Mixtures of carotenoids with ascorbic acid at 0.1 g l − 1 exerted a tendency, not significant though, for increasing the activity of each individual carotenoid. Industrial relevance: The goal of this work was to develop a model for quality and storage stability determination of confectionary products using crystallization of sugar shell in hard panning process as example. The model developed can successfully predict the concentration profile and growth of sugar crystals in a thin film and it’s industrial relevance is evident by the industrial financial support.

5,7,3′,4′-hydroxy-substituted flavonoids are considered as very efficient radical scavengers. This study examines the effect of the structural elements of the C-ring, on the radical scavenging activity of these compounds. The impact of di-hydroxy substitution of A- or B-ring on the activity of fully substituted C-ring flavonoids was also studied. Quercetin, luteolin, taxifolin, eriodictyol, rutin, (+)-catechin, (−)-epicatechin, fisetin and kaempferol were studied during the reaction with the DPPH radical; they revealed two distinctive steps of reaction, a first rapid and a second slower. DPPH scavenging followed second order kinetics during the rapid step; stoichiometric factors and rate constants were determined. Quercetin and fisetin scavenged four radicals by each molecule, while the other flavonoids scavenged two radicals with a consequent production of B-ring diquinone. Also the rate constants were affected by C-ring structure. The kinetics of the slow step was much more complicated and the contribution of C-ring was based on stoichiometry. Industrial relevance The oxidation of oils, fats and fat-containing foods is a major problem for the food industry, because it is directly related to economical, nutritional, flavour, safety and storage problems. The use of antioxidant compounds can slow down the process of oxidation and thereby increase the shelf-life of the products. Due to probable mutagenic and carcinogenic properties of several synthetic antioxidants, there is an increasing demand from consumers for their replacement with natural compounds of similar action. Flavonoids are plant polyphenols, which display antioxidant activity as well as several beneficial pharmacological and biochemical actions, thus could be used as natural antioxidant and upgrade the quality of a product. A better understanding of the reaction of flavonoids with free radicals would elucidate their mode of action against peroxyl radicals. The relation of structure to antioxidant activity can enhance the recovery of specific compounds from herbs or agro-industrial by-products and their exploitation as natural antioxidants.

The antioxidant efficiencies of 5,7,3′,4′-hydroxy-substituted flavonoids were examined. The tested compounds (quercetin, luteolin, taxifolin, (+)-catechin and eriodictyol) were selected with a view to their C-ring differentiated pattern. Each one was added in cottonseed oil at equimolar amounts and the retardation of lipid peroxidation was estimated by means of peroxide value. Furthermore, their ability to scavenge DPPH radical was studied in two solvents (methanol and ethyl acetate) and the DPPH method proved a satisfactory prediction test for the antioxidant action of flavonoids in oils when methanol was used as the reaction media. Furthermore, the comparison of the C-ring structural element contribution to the antioxidant action revealed the full substitution to be the most important followed by the 3-OH and 2,3-double bond in the presence of the 4-carbonyl. Concerning the monosubstituted flavonoids, the 4-carbonyl group induced minor activity, whereas the 3-OH increased significantly the antiradical and antioxidant action.

The storage stability of potato chips removed from a continuously operated fryer at various time intervals was estimated by the rate of increase of peroxide value and conjugated dienes of the oil absorbed in the chips. Operation temperature varied from 155 to 195 °C. The extent of deterioration of potato chips was correlated with the oxidation indexes of frying oil. The results showed that peroxide value and conjugated dienes increased linearly with storage time. The rates of increase were higher for higher frying temperature and longer process time, and correlated linearly with the oxidation indexes of the frying oil at the moment that the chips were removed.

The deterioration of oil during successive fryings of potato chips, especially the accumulation of polar compounds, was studied in the temperature range 155–195 °C. The content of polar compounds increased linearly with process time. The analysis of individual polar compounds showed that the products of thermal and oxidative degradation dominated over the products of hydrolytic cleavage as frying proceeded. Dimeric triglycerides increased linearly with process time, while polymerised triglycerides increased exponentially. The rate constants of the degradation reactions increased slightly with temperature, following an Arrhenius-type equation. Oxidised triglycerides increased with frying time up to 6 h, thereafter remaining constant or increasing further upon prolonged frying. The increase was greater at higher temperature. The products of hydrolytic cleavage were not significantly affected by temperature. Mono- and diglycerides increased initially to reach a plateau, while free fatty acids remained almost constant throughout frying. The thermo-oxidative alterations induced by heating the oil were also measured and compared with those observed during frying at the same temperature. Dimeric and polymerised triglycerides showed higher rates of increase during heating as compared with frying at the same temperature. © 2003 Society of Chemical Industry

The effect of oregano on the oxidative stability of cottonseed oil during frying of potato chips and on the storage stability of the produced chips was studied. The ground spice or an ethanol-derived extract thereof was added to the oil at a concentration of 2 g l−1 (dry basis) before frying. The results showed that both ground oregano and its ethanol-derived extract decreased the rates of accumulation of conjugated dienes, polar compounds, polymerised triglycerides, dimeric triglycerides as well as p-anisidine value (p-AV) of the frying oil. The major decrease was observed in the accumulation of polymerised and dimeric triglycerides. The accumulation of oxidised triglycerides showed a low decrease with the addition of oregano, while the hydrolytic compounds formed during frying were not affected. No significant difference (at 95% significance level) between ground oregano and its ethanol-derived extract was observed. The storage stability of potato chips removed from the fryer at various time intervals was estimated by the rates of increase in peroxide value and conjugated dienes of the oil absorbed in the chips. Both rates were depressed when oregano was added to the frying oil; the protective action of oregano extract was considerably greater (at 95% significance level) than that of ground oregano. Copyright © 2003 Society of Chemical Industry

Fat mimetics, namely Raftiline, Simplesse, C*deLight and polydextrose, diluted in water to give a gel with 200 g kg−1 concentration, were used for partial fat replacement and polyols, namely lactitol, sorbitol and maltitol, for sugar replacement in low-fat, sugar-free cookies. Raftiline, Simplesse or C*deLight combined with lactitol or sorbitol in 35% fat-reduced, sugar-free cookies resulted in products with hardness and brittleness comparable to those of the control. Polydextrose as fat mimetic and maltitol as sugar substitute resulted in very hard and brittle products. Further fat replacement to 50% was achieved using Raftiline, Simplesse or C*deLight combined with a blend of lactitol and sorbitol; however, the final products were hard, brittle and did not expand properly after baking. Cookies prepared with Simplesse had the least acceptable flavour, while cookies prepared with C*deLight were rated as the most acceptable by a sensory panel. The textural properties were improved by either decreasing the amount of alternative sweetener or increasing the concentration of fat mimetic in the gel which was added to the cookies. All fat-reduced, sugar-free cookies prepared in this study had higher values of moisture content and water activity than the control, but these values were below the upper limit that affects cookie shelf-life. © 2002 Society of Chemical Industry

Moisture loss and oil adsorption kinetics, structural properties (apparent density, true density, specific volume and internal porosity), color changes and viscoelastic behavior (compression tests, crispness) were investigated during deep fat frying of french fries. The effect of frying conditions (oil temperature, sample thickness and oil type), drying pretreatment and osmotic dehydration pretreatment on the above properties was also examined. The results showed that oil temperature and thickness of potato strips have a significant effect on oil uptake, moisture loss and color parameters of french fries, while the use of hydrogenated oil in the frying medium does not affect these properties. The porosity of french fries increases with oil temperature increases and sample thickness and it is higher for products fried with hydrogenated oil. Maximum stress and maximum strain increase during frying, while crispness of potato strips is higher for hydrogenated oil, and lower for refined oil. Air drying and osm...

Soft‐type cookies were prepared with up to 35% fat replacement by fat mimetics, namely Litesse (improved polydextrose), C*deLight MD 01970 (maltodextrins), Dairytrim (b‐glucans), pectin and Simplesse Dry 100 (a blend of micropatriculated whey proteins and emulsifiers). Physical, textural and sensory properties of the cookies were measured. All formulations with fat replacement up to 23% showed properties similar to control cookies except hardness. Cookies with 35% fat replacement by Litesse, a combination of Litesse and C*deLight MD 01970 and a combination of Litesse and Simplesse Dry 100 (50% each) presented a greater hardness, but physical properties as well as flavor and general acceptance comparable to the control cookies.

The effect of sucrose replacement by polyols or fructose on dough rheology and properties of low-fat cookies was studied. Polydextrose was used to replace 35% of fat in low-fat cookie formulations. The rheological properties of dough were affected by sugar replacement. Maltitol and fructose resulted in dough with high values of hardness and consistency and low adhesiveness and cohesiveness, while lactitol, sorbitol and xylitol had the opposite effect. The properties of cookies prepared with maltitol and lactitol were similar to sucrose ones. Sorbitol cookies had acceptable properties too. In addition, lactitol and sorbitol improved the texture of low-fat cookies, making them softer and less brittle. Xylitol also affected texture favourably, but not flavour. Mannitol was found not suitable for cookie formulation, as it restricts spread and imparts unpleasant flavour and appearance to the cookies. Fructose was judged unacceptable too, because it led to bitter aftertaste and dark colour. Cookies with polyols or fructose were less sweet than sucrose ones, but supplementation with acesulfame-K increased sweetness and improved perceived flavour and general acceptance. # 2000 Society of Chemical Industry

Salt solutions were used in isolating tomato seed meal proteins. Na 2 SO 3 and NaCl solutions at different concentrations, and pH were included in a central composite design to find optimum conditions of protein isolation. The highest total protein yield was achieved with water extraction (no salt present). Salt extraction at pH 7.5 produced Isolates with protein content of 93.4% (NaCl 5% w/v) and 77.1% (Na 2 SO 3 0.5% w/v). Observed values were in good agreement with predicted values. Isolates extracted with different salt solutions ranged from less soluble but very resistant to heat and Ca 2+ , to very surface active with functional properties comparable to commercial soy isolates.

Water extraction of tomato seed meal proteins was studied to find optimal conditions for protein extraction and isolation. A central composite design including temperature, pH, time and water/solids was used and second order models were employed. Optimum conditions were: 5O”C, pH 11.5, 20 min and water/solids = 30/l (v/w). Experimental values were: extraction yield (extracted protein to that in raw material) 66.1%, protein content of product 72.0%, and total protein yield (protein in isolated product to that in raw material) 43.6%. Estimated values were in good agreement with experimental values. Optimum conditions were confirmed by a larger scale experiment.

Press liquor from the dewatering of orange peel was used as a substrate for citric acid production. Of the three strains of Aspergillus niger examined, strain NRRL 599 produced the greatest amount of citric acid. The conditions favouring citric acid production were pH 5.0—6.2 in the presence of 40 ml kg−1 methanol. Under these conditions 30 g of citric acid per kg of press liquor were produced, representing a yield of 630 g kg−1 based on sugars consumed. The yield was further increased to 730 g kg−1 by thermal pretreatment of the press liquor.

The antioxidant activities of combinations of plant extracts and primary antioxidants or citric acid were studied in lard stored at 75°C. Methanol extracts of oregano, thyme, marjoram, dittany, rosemary and sage were used. When combined with butylated hydroxyanisole, butylated hydroxytoluene or ascorbyl palmitate the extracts showed an additive antioxidant effect, while combinations with propyl gallate did not increase the induction period obtained by the phenolic antioxidant. Negative synergism was observed when the plant extracts were mixed with DL-α-tocopherol. Citric acid showed a high synergistic efficiency with marjoram extract and a minor one with thyme extract, but it had a negative effect with all the others. Ternary mixtures of the plant extracts with citric acid and ascorbyl palmitate had lower activity than the corresponding dual combinations with ascorbyl palmitate, except for the mixture of marjoram extract.

The antioxidant activities of methanol extracts of oregano, dittany, thyme, marjoram, spearmint, lavender and basil were tested in lard stored at 75°C. The concentration of extracts in lard varied from 0.01 to 0.20%. Oregano extract was found to be the most effective in stabilizing lard, followed by thyme, dittany, marjoram and lavender extracts, in a decreasing order. The induction period of lard increased with antioxidant concentration. After the induction period, peroxide formation proceeded rapidly, following pseudo-zero order reaction kinetics. The rate of the reaction decreased slightly with increasing plant extract concentration. Combined addition of plant extracts in lard showed a low synergistic action between thyme extract and spearmint extract.

Pectin was extracted from dry orange waste with nitric acid. A factorial experimental design was used and the effects of temperature, time and pH of extraction on pectin yield and ‘jelly units’, ie pectin yield × viscosity of pectin solution were determined. Optimum conditions for pectin extraction are also discussed. According to ash and methoxyl content determinations the product can be classified as low ash and high methoxyl pectin. Its purity expressed as anhydrogalacturonic acid content varied from 68.5 to 75.0%.

Carotenoids were extracted from fresh orange peel with various solvents. Acetone was the most efficient of the solvents tested. Two successive extractions with acetone after an initial washing with either acetone or methanol were adequate to remove 89% of the total carotenoids. The extracts were concentrated, the carotenoids transferred to hexane and a crude pigment concentrate was obtained by hexane evaporation. Water washings prior to acetone extraction eliminated the solvent-solvent transfer to hexane. The extraction residue was used for pectin recovery. Carotenoid removal from the peel did not affect the yield and quality of the pectin.