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Durum wheat is the raw material of choice for the manufacture of superior quality pasta products. However, in some parts of the world many pasta producers have to use common wheat to make pasta, which shows a deficiency with respect to quality attributes. In this respect, the functionality of different hydrocolloids in a weak common wheat flour was investigated as a comparative study with the objective to improve pasta-making potential under industrial processing conditions. Six commercial hydrocolloids, sodium alginate (AL), propylene glycol alginate (PGA), xanthan gum, carrageenan, locust bean gum or guar gum were added to wheat flour at 0.5% and 1% substitution. A rheological investigation, based on dynamic small strain tests and large deformation tests (farinograph and amylograph analyses) was performed to evaluate differences in dough structure due to interactions between flour components and hydrocolloids, and related to cooking properties of pasta. All hydrocolloids promoted an increase in elastic interactions in the dough. The strongest doughs were obtained by addition of alginates. Only cooked pasta supplemented with AL, PGA and XG showed an increase in firmness compared with the reference (PGA > AL > XG). The product enriched with 0.5% PGA or 1% AL gave the highest overall acceptability and sensory scores. On the contrary, xanthan gum, carrageenan, locust bean gum or guar gum performed relatively poorly in flour. On the basis of these results alginates were the most effective improvers of pasta quality among different hydrocolloids.

International audience; Poly(lactic acid) (PLA) is the most traded biodegradable and biobased material. It is largely used as ecofriendly substitute of conventional plastics. Nevertheless, one of the main limiting factors is its water sensitivity. PLA reacts with water and is hydrolyzed during time, which determines its performance. Limited information related to the hydrolysis mechanism driven by water in vapor state is available in scientific literature. Literature is mainly focused on the effects of water in liquid state. This lack of information is of significant importance, since PLA interacts with water in both phases. This work was aimed to give a full depiction of the chemical and physical changes of PLA in a large range of relative humidity environments (from 50 to 100% RH) and in contact with liquid water. This research clearly showed that the stability of PLA was influenced not only by the chemical potential of water molecules, but also by their physical state due to a different behavior of degradation products. From a practical point of view, the findings of this study can be used as strong scientific basis for giving recommendations about the use of this material in its applications as packaging or mulch films.

Pasta is traditionally manufactured using only durum wheat semolina, but it is possible to incorporate other flours or ingredients into pasta in order to increase its nutritional value to the consumer, compared to conventional pasta. For this reason, pasta was prepared substituting durum wheat semolina with 15% of enriched dietary fibre flours (Glucagel, inulin Raftiline® HPX, inulin Raftiline® GR, psyllium and oat). Moreover, all dietary fibres (excluded Glucagel) were added in combination in order to evaluate their possible antagonistic or synergic effect on predicted glycaemic response. In general, all enriched dietary fibre pasta sample showed a significant decrease (except for pasta containing a combination of 7.5% inulin Raftiline® GR and 7.5% oat bran flour) in reducing sugars released and standardised AUC values compared to control pasta. However, this study showed that the combination of dietary fibres in pasta formulation led to an antagonistic effect on the predicted glycaemic response.

The production of high quality functional pasta from non-conventional raw materials represents a challenge. A partial substitution (15 g/100 g) of durum wheat semolina with long-chain inulin (HPX) and short-chain inulin (GR), Glucagel, psyllium and oat material (added individually and in combinations) was performed in order to increase the level of dietary fibre intake. The cooking, textural and colour characteristics of the pastas were evaluated and compared to control sample containing exclusively durum wheat semolina. Generally, material addition to the durum wheat pasta increased cooking losses, swelling index and water absorption, whilst reduced firmness and resistance to uniaxial extension of pastas. Raw spaghetti samples resulted significantly darker ( L *) and more redness ( a *) than control pasta. In the cooked pasta, all inulin enriched samples were brighter than semolina pasta. Pasta prepared with 15 g/100 g semolina of oat flour showed the best performance (except for the colour) compared to the other experimental pasta samples, but was significantly different to control durum wheat sample. Combinations of fibre rich additions were studied with the inclusion of inulin GR having a less deteriorating effect when added in combination with oat flour. This illustrates that some fibre rich sources may act better in combinations than separately.

International audience; This work investigated the sorption and the diffusion properties of CO2 under high pressure and the further modificationsinduced in Poly(lactic acid) (PLA) thin layers. Poly(ethylene terephtalate) (PET) was also considered for comparativepurposes. Firstly, from thermodynamic equilibrium, the CO2 sorption isotherm (two sorption-desorption cycles, up to25 bar, at 25 °C) gave strong evidence of a physisorption mechanism and of a hysteresis phenomenon. Infrared spectroscopyanalysis confirmed that no chemical reaction occurred. Secondly, from the kinetics aspect, the CO2 diffusion coefficient wasfound around 10–13 m2·s–1 and was slightly faster for sorption compared to desorption. Additionally, when CO2 sorption occurred,the PLA structure and its functional properties were modified due to plasticization and swelling. CO2 plasticizationreduced the glass transition temperature of PLA and accelerated the physical ageing of the polymer. These results are thereforeof significant importance in industrial processing and applications which involve close contact between CO2 and PLA.

International audience; Various types of food are now commercialized in packaging materials based on poly(lactic acid) (PLA) due to its eco-friendly nature. However, one of the main limitations related to PLA is its reactivity with water. For food applications, it is of critical importance to better understand the hydrolysis of PLA driven by water molecules either in liquid or in vapour state. This work focuses on the modifications of PLA induced by water when simulating contact with semi-dry foods (aw ≈ 0.5), high moisture foods (aw ≈ 1) and liquid foods (aw ≈ 1). This study undoubtedly shows that both the chemical potential of water and its physical state influence the hydrolytic degradation of PLA films. From a practical point of view, PLA packaging is very well suited for semi-dry foods, but is highly sensitive to high moisture and liquid foods.

A high density polyethylene (HDPE)/calcium carbonate (CaCO(3)) film containing TiO(2) was prepared via blown film extrusion process. The photocatalytic properties of this film were evaluated by voltammetric, UV-Vis spectrophotometric and gas chromatographic measurements following the decomposition rate of suitably selected molecular probes, such as 4-hydroxybenzoic acid and methylene blue. The film containing 1% w/w of TiO(2) displayed a profitable and reproducible photoinduced degradation activity towards target organic compounds. The effect of packaging photocatalytic activity on the structural and microbiological stability of a short-ripened cheese was studied. Cheese structure was assessed by dynamic, small deformation rheological tests. A container consisting of a multilayer material, where the layer brought in contact with the food, made from the HDPE+CaCO(3)+TiO(2) composite matrix, was able to provide a greater maintenance of the original cheese structure than a rigid container currently used, mainly due to the inhibition of lactic acid bacteria and coliforms.

International audience; Different types of PLA films treated by corona are currently available in the market for coating or printing applications. However, data relative to its impact on PLA film properties are scarce and do not generally consider industrial scale production. The objective of this study was to assess the impact of corona treatment on the surface, structure and barrier properties of bi-oriented PLA films produced at industrial scale. Thus, a comparative study between corona treated (CT) and non-corona treated (NCT) PLA films was conducted.The surface of films was studied using Attenuated Total Reflectance Fourier Infrared Spectroscopy (ATR-FTIR), X-ray Photoelectron Spectroscopy (XPS), Atomic Force Microscopy (AFM) and goniometry measurements. The structure of films was analyzed with thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and uniaxial tensile analysis. The barrier properties of films to three gases (He, O-2, CO2) were also determined.This study unambiguously revealed that corona treatment led to modifications in both surface and bulk of PIA films. In particular, surface analysis displayed the well-known capability of corona treatment to chemically and physically modify the surface of PLA films at the nanometer scale by increasing polarity and roughness. The structural analysis displayed a slight increase in the crystallinity degree and slight modifications in mechanical properties of films. This probably originated from temperature increase associated to corona treatment, which favored physical changes (e.g. relaxation, crystallization) of a part of the bi-orientated PIA chains, and therefore highlights the importance of such an industrial step on the film properties for packaging applications. As a result of these modifications, the barrier properties of films to three gases (He, O-2, CO2) are also slightly improved.

Stracchino is a short ripened soft cheese mainly produced in the North of Italy. The changes in Stracchino cheese quality are mainly attributable to microbial spoilage and structure breakdown because of enzymatic activity. The aim of this work was to evaluate the effect of different packaging materials on the shelf life of Stracchino cheese, monitoring changes in rheological, microbiological and sensorial properties over 28 days at 4C. Three packaging materials were compared in order to optimize the suitable packaging for Stracchino cheese: (1) paper-polyethylene as a reference package commonly used for this product [R]; (2) commercial high-density polyethylene (HDPE) -based film, mainly composed of calcium carbonate and HDPE (Ovtene® [OV]); and (3) experimental active packaging obtained with addition of potassium sorbate to OV (active Ovtene® [AOV]). The OV and AOV resulted more effective to control microbial spoilage than R, without affecting sensorial and chemical properties. AOV allowed the inhibition of yeast growth, probably because of the activity of potassium sorbate. The gel structure, which characterizes the Stracchino cheese, was maintained until 21 days with the application of AOV, while a liquid-like behavior was associated to the sample packed with the reference material after 14 days. Microbiological, rheological and sensory results demonstrated the effectiveness of AOV in prolonging Stracchino cheese storability. Practical Applications In the last years, the research in food packaging have been focused on the development of active packaging, able to interact with food and surrounding media. These innovative materials could be applied in order to extend shelf life of food products. The application of films with potassium sorbate to a short ripened soft cheese resulted effective to maintain product structure and to control microbial spoilage. Active packaging selected in this study could be used as packaging material for this type of cheese in order to prolong shelf life.

The aim of this work was to investigate the effects of hydrocolloid addition on rheological properties and breadmaking performance of rice-buckwheat batter at different water levels. Xanthan gum (XG) and propylene glycol alginate (PGA) were added to rice-buckwheat blend (60:40) at levels of 0.5–1.5%. Batter rheological properties were investigated using dynamic measurements in the linear viscoelastic range (frequency sweep and time cure tests). The addition of both hydrocolloids significantly enhanced the storage modulus (G′) of batter. XG exerted greater effect on G′ than PGA. Different effects on starch gelatinisation were observed for the two hydrocolloids. PGA breads showed higher improvement in terms of increased specific volume (V s ), decreased crumb firmness and crumb structure than XG breads. Different technological behaviours were explained on the basis of batter rheological properties.

Flavour loss strongly affects food quality. In order to decrease flavour changes during food conservation, different strategies could be used. Aroma compound encapsulation allows the protection of food flavour from loss and degradative reactions, like oxidation. Edible films could be an encapsulation matrix: in the case of emulsified film, lipid globules incorporated can act as carriers of active molecules, such as aroma compounds. Edible films prepared from ι-carrageenans are interesting for good mechanical and gas barrier properties. The aim of this study was to encapsulate different aroma compounds in an ι-carrageenan emulsion based edible film. Release of ten aroma compounds was compared to that obtained from a lipid matrix, Grindsted Barrier System 2000 (GBS), was also used as an edible film formulation. Flavour release was followed by HS-SPME measurements. This study allowed the influence of both matrix and aroma compounds characteristics on flavour release to be investigated. This study presents new understanding of the role of emulsion based edible films as a matrix able to encapsulate aroma compounds. Carrageenans films were possible encapsulating matrixes because they showed better performances for retention of more polar aroma compounds than the usual lipid supports. Carrageenans films were able to retain volatile compounds during film-process formation, and to release gradually with time.

The experience of food can be affected by visual perception and the context in which food is presented. In this study, we investigated the effect of specific emotional contexts on food desirability. To this purpose, we selected a highly familiar Italian food, Pizza Margherita, whose sauce color was digitally manipulated to create different desirability levels. The participants rated the pizza desirability on the basis of its visual features alone (no-context condition) and, most critically, after viewing images representing facial expressions of happiness, anger and neutrality. Anger was selected, as opposed to disgust, as a food-unrelated emotion to assess whether influential effects on food desirability evoked by the observed individual’s emotion state needs to be necessarily related to the eating context. Confirming previous results, we found an effect of the social context (facial expressions) on food desirability. Similarly to the no-context condition, happiness evoked the highest desirability ratings for all items compared to neutral and angry expressions, whereas the neutral and angry faces negatively affected food desirability relative to no-context and happy face conditions. These findings show that happiness is commensurate with a situation in which food is presented alone, suggesting that approach to food in healthy individuals is intrinsically related to positive emotions. Additionally, we show that food perception can be also affected by emotions, which are not necessarily related to food, but which nevertheless frame food delivery. We argue that this emotion-related effect may be grounded on resonance ‘mirror’ mechanisms allowing people to spontaneously tune to others’ emotions.

This study investigates the effect of different types of surfactant (glycerol monostearate, Tween 60, and Tween 80) on water vapor permeability (WVP), tensile strength (TS), percentage elongation at breaking (E), and structure of an emulsified edible film composed of cornstarch, methylcellulose, and cocoa butter or soybean oil. Factorial designs at two levels were used to analyze the effect of emulsifier (EM) and lipid content on the functional properties of film. Results showed that the effects of independent variables on WVP, TS, and E depend on surfactant and lipid type. The presence of EM significantly decreased the WVP of cocoa butter films but did not improve the barrier or mechanical properties of soybean oil-based film.

The optimum combination of high-pressure (HP), mild temperature application and holding time on pigskin-derived, gelatin-based, film-forming solutions to improve the barrier properties of packaging films was determined using response surface methodology. Results showed that the variable response oxygen transmission rate (OTR) decreased significantly using a combination of temperature, time, and the interaction between pressure and time. The determined optimum conditions to minimize the OTR were high pressure treatment (600 MPa) and holding time (30 min), while maintaining the temperature at 20.5 °C. In parallel, films obtained at the optimum conditions (OPT) were characterized for structural, thermal, mechanical, water vapor transmission rate (WVTR) and color properties. OPT films were significantly affected by mechanical (TS), thermal (Tm), WVTR properties and redness a* values compared to untreated control samples. Overall, a combination of HP, mild temperature and holding time on film-forming solutions showed interesting potential in altering film characteristics, especially in the enhancement of barrier properties. Industrial relevance Results obtained in this study are of considerable importance for the film development and the shelf-life of food products packaged in films treated with the methodology used in the current work. The oxygen permeation through the film packaging can lead to a degradation of the quality attributes of the food products influencing microbial development as well chemical and enzymatic degradation pathways. Oxygen is responsible for oxidative rancidity of unsaturated fats with the development of undesirable flavors and aromas and a loss in vitamin C. The package oxygen permeability plays a key role in affecting the internal partial pressure of a packaging system and for this reason the oxygen permeability is probably the property mostly tested for the different packaging materials. Within this contest, the industrial relevance of this study is significant, since the results showed a potential application of a combination of high-pressure, mild treatment and holding time to increase barrier properties in bio-sourced packaging films thus extending the shelf-life of foodstuffs.

Nutritional quality parameters, microbiological and technological quality indicators (condition index, meat yield and water-holding capacity) of blue mussel, Mytilus galloprovincialis , reared in the North Adriatic Sea were characterised at monthly intervals over a 1 year period. Contents of protein (7.5–11.6 g/100 g), lipid (1.0–2.2 g/100 g) and ash (2.2–3.3 g/100 g) varied significantly accordingly to condition index (6–15%). n-3 PUFAs were the predominant fatty acids (38.7–45.9% of fatty acids) and docosahesaenoic and eicosapentaenoic acids were the most abundant (167 and 93.3 mg/100 g, respectively). Glycine, glutamic and aspartic acids accounted for 40% of total amino acids. All samples exhibited limited concentrations of Cr, Mn, Ni, Cu and Zn, as well as Na. M. galloprovincialis from the North Adriatic Sea showed the highest technological and nutritional quality, considering also the inter-annual variability, in late spring, which corresponds to the period immediately before gamete release.

Filled snacks are new industrial co-extruded products made by a dough shell and an internal filler constituted by salty or sweet cream. Due to different rheological characteristics of fillers and dough, it is difficult to choose operational variables capable of guaranteeing a complete filling. This work aims to determine the optimal rheological properties of both filler and dough to make an optimal product without undesired voids. A typical dough and several fillers have been considered and rheologically characterised by means of dynamic oscillation, steady shear flow and creep tests. A dynamic temperature ramp test at 1 Hz was performed to determine temperature dependency of the tested material. A time–temperature shifting technique based on a modification of the Cox–Merz rule and on weak gel model was applied to extend the flow curve range and to overcome temperature experimental difficulties. The obtained data, expressed by a power law correlation, were inserted in a numerical algorithm previously developed, and the internal swelling of the dough followed by a recovery was computed during mixed flow inside the extrusion head. It was suggested that a greater recovery implies a better filling capability because the filler may follow the dough during swelling. Simulations indicated that a complete filling was obtained only for the materials exhibiting a quite stable network during the flow. The experimental results obtained by preparing different industrial filled snacks confirmed the simulative predictions. Quantification of the network shear stability was determined by comparing the loss modulus (G″) and shear viscosity (η) values. In particular G″ versus frequency and η versus shear rate were fitted by a power law model and the best fillers must present a ratio between their exponents close to 1.

Filled snack production has been considered from several point of views. In this work, the effect of the operational variables on the cereal mixture constituting the external part of this product has been studied. A typical flour blend was characterised and used in a previous developed model to simulate the extrusion conditions and to show process damage. Chemical and rheological methods are proposed as experimental techniques capable of measuring the damage induced by the process. The link between chemical contents and mechanical damage was proposed on the basis of the thermal history and of the mechanical power input. The simulation results obtained by a new proposed extrusion model applied to a real twin co-extruder, made it possible to predict damage such as the lysine decrease, and to show the effect of different screw speeds. It appeared that the computed results are in an acceptable agreement with industrial evidence.

Dynamic measurements were made with a controlled stress rheometer to study the viscoelastic properties (G', G', δ) of wheat doughs (45% wb water content) for fresh pasta production prepared with different blends of durum wheat semolina and common wheat flour with different concentrations of sodium chloride. Increasing the semolina and sodium chloride content, increased the strength and the solid-like behaviour of semolina-flour blends. The physical properties of dough were strongly dependent on particle size distribution and salt addition. By manipulating semolina-flour ratio and ionic strength, it was possible to obtain semolina-flour doughs with a rheological behaviour close to that of pure semolina dough.

Nanocomposite films were produced by blending semicrystalline PLA with different types of OMMTs using extrusion. In order to study their effect on optical, structural, and thermal properties, they were added at a fixed nominal concentration of 5% w/w and compared with pure PLA films. The XRD measurements showed that the incorporation of small amounts of nanoclays resulted in a formation of nanocomposites, with the C30B demonstrating the greatest compatibility with PLA. An increase in UV barrier properties was observed in nanocomposites, with Closite® C20A showing the best performance. The content of L -isomer in PLA significantly affected the thermal properties of the films, with a decrease in T m of about 14 °C and increase in T c of about 20 °C when the matrix, possessing a higher D -isomer content, was used. FTIR results showed a strong interaction between the nanoclays and the two different PLA matrices, due to the appearance of new peaks in nanocomposites films at around 520 and 627 cm −1 .

Cereal products are consumed daily by the majority of the population. Popular belief is that these cereal products, rich in carbohydrates, produce a high glycaemic response and may not be a contributing factor to the obesity epidemic throughout the world. Recently the food industry has investigated ways of improving the overall nutritional balance of carbohydrate rich foods and focused on increasing their dietary fibre (DF) contents at the expense of readily digestible carbohydrates. It is well documented that dietary fibre is involved in disease prevention and enhanced health of consumers. Moreover, the food industry can take advantage of the physicochemical properties of fibre to improve the viscosity, texture, sensory characteristics and shelf-life of their products. The focus of this review paper is on the influence of DFs (inulin, fructo-oligofructose, β-glucans, arabinoxylans and resistant starch) supplementation on the quality and nutritional aspects of common foods containing cereals- pasta, bread, muffins/cakes and extruded snacks. This review reports on the evidence regarding fibre enrichment of cereal foods and looks at the advances and future trends in enriched dietary fibre cereal products.

International audience; Edible films may act as carriers of active molecules, such as flavors. This possibility confers to them the status of active packaging. Two different film-forming biopolymers, gluten and ι-carrageenans, have been compared. d-Limonene was added to the two film formulations, and its release kinetics from emulsion-based edible films was assessed with HS-SPME. Results obtained for edible films were compared with d-limonene released from the fatty matrix called Grindsted Barrier System 2000 (GBS). Comparing ι-carrageenans with gluten-emulsified film, the latter showed more interesting encapsulating properties: in fact, d-limonene was retained by gluten film during the process needed for film preparation, and it was released gradually during analysis time. d-Limonene did not show great affinity to ι-carrageenans film, maybe due to high aroma compound hydrophobicity. Carvone release from the three different matrices was also measured to verify the effect of oxygen barrier performances of edible films to prevent d-limonene oxidation. Further investigations were carried out by FT-IR and liquid permeability measurements. Gluten film seemed to better protect d-limonene from oxidation. Gluten-based edible films represent an interesting opportunity as active packaging: they could retain and release aroma compounds gradually, showing different mechanical and nutritional properties from those of lipid-based ingredients.

Gluten films obtained in acid conditions display some protein dispersion difficulties. Ultrasound treatment (UT) could represent an interesting strategy for improving gluten film appearance. Different UT exposure times were applied to film-forming dispersion. The aim of this work was to investigate the effect of ultrasound treatment on gluten-based films at molecular and mesoscopic levels. Distribution in gliadin and glutenins was determined with SE-HPLC. The UT improved protein dispersion and final film appearance. Sonication did not lead to large changes in various gluten fractions, which suggests absence of important protein breakdown at the molecular level. Gluten showed high tolerance to UT. Surface properties of untreated and treated films were investigated by contact angle measurement: sonication promoted hydrophilic surface properties. Industrial relevance Bio-based packaging has been receiving increasing attention in view of its beneficial impact on the environment. Among proteins, gluten resulted as a very interesting film-forming material. Gluten films prepared in acid conditions showed problems in protein dispersion. Sonication represents a physical strategy which allowed us to obtain gluten-based films without the addition of chemical additives, such as sodium sulphite.

BACKGROUND: β-Glucans have enjoyed renewed interest as a functional food ingredient, with current attention focused on optimising β-glucan levels in finished products without compromising final product quality. In order to measure the uncertainty about the level of β-glucans in barley, two different statistical methods (Bayesian inference and Bootstrap technique) were applied to measured levels of β-glucan in three different varieties of barley grain (n = 83). RESULTS: The resulting probability density distributions were similar for the full data set and also when applied to smaller sample sizes, highlighting the potential for either method in quantifying the total uncertainty in β-glucan levels. Bayesian inference was used to model the effect of nitrogen treatment on β-glucan and protein contents in barley. The model found that a low level of fertilisation (50 kg N ha−1) did not have a significant effect on β-glucan or protein content. However, fertilisation above this level did result in an increase in β-glucan and protein levels, the effect seeming to plateau at 100 kg N ha−1. In addition, the uncertainty distributions were significantly different for two consecutive years of data, highlighting the potential environmental influence on β-glucan content. CONCLUSION: The model developed in this study could be a useful tool for processors to quantify the uncertainty about the initial level of β-glucan in barley and to evaluate the influence of environmental factors, thus enabling them to formulate their ingredient base to optimise levels of β-glucan without compromising final product quality. Copyright © 2009 Society of Chemical Industry

The aim of this experimental work was to evaluate the effect of inulin addition on the rheological properties of common wheat doughs and bread quality. Three commercial fructan products of different number average degree of polymerisation (DPn) were used (DPn = 10 for inulin ST; DPn = 23 for inulin HP and HP-gel). Inulin contents from 2.5 to 7.5% on dry matter (wheat flour plus inulin) were used. Dough rheological properties were investigated using farinograph and dynamic rheological measurements. Upon addition of dietary fibre (DF), significant increase in mixing time and stability, and decrease in water absorption were recorded. Inulin ST exerted greater effect on water absorption than HP products. Inulin with high DP determined large changes in linear viscoelastic properties of dough. The storage modulus (G′) gradually increased and tan δ decreased with increasing levels of inulin HP and HP-gel, which contribute to the overall dough elasticity and strength. The increase in solid-like behaviour with DF content prevented expansion of wheat dough during the fermentation stage. No significant differences were observed between sample HP and HP-gel. Enrichment with inulin ST led to lower changes in linear viscoelastic properties of dough at farinograph water absorption than inulin HP. Bread volume was significantly reduced and crumb hardness was enhanced by inulin HP level in the range 5–7.5%. When inulin ST was added to a flour suitable for breadmaking, a trend of increasing bread volume with the increase of DF content was found.

Structure formation in dough systems is the result of an interplay between processing conditions and subsequent interactions in the protein phase. These interactions can be both of a covalent (disulfide bonds) and physical nature and occur at all length scales. The aim of this work was to investigate the effect of simple shear deformation at various shear rates on wheat dough rheological properties, microstructure and GMP fraction. Shear processing was compared with a z-blade mixing. The contribution of disulfide bonds on different length scales was investigated using NEMI as SH-blocker agent. Dough strength and strain hardening decreased with the increase in shear rate leading to dough weakening. Sheared dough at low shear rate exhibited the highest strength among doughs under large deformation conditions. Mixing or shearing in the presence of NEMI strongly reduced fracture properties and GMP content of mixed and sheared doughs. Only the dough that was sheared at low shear rate still exhibited some strength and strain hardening. Large deformation results were integrated with linear viscoelastic properties using low shear rate–long time creep tests. Elastic compliance curves for reference doughs were lower than the dough containing NEMI. Shearing at low and intermediate shear rates gave similar elastic compliance. Dough rheological behaviour was interpreted in the context of polymer gels containing reversible cross-links and physical interactions. Shearing led to the formation of a heterogeneous structure. Very large protein domains were observed for dough at low shear rate, which became smaller upon higher shear rates suggesting that those structures are quite weak. When NEMI was present, large protein structures were lost more easily. The break-up of gluten domains during mixing and shearing was proposed to be a result from a different mechanism.

The rheological properties of edible film-forming dispersions containing corn starch, methylcellulose (MC) and glycerol were studied using oscillatory and steady shear flow tests. The combined effects of glycerol content and blending levels of MC with starch on the rheological properties of dispersion were evaluated. The flow curves showed shear-thinning behaviour. Mechanical spectra and Cox–Merz superposition of steady-shear viscosity and dynamic viscosity were consistent with polymer solutions containing topological entanglement interactions of chains. Dispersion stability results showed total recovery of the viscoelastic properties of dispersions subject to high strains, as expected for entangled polymers. MC was the main factor influencing apparent viscosity and viscoelastic properties.

Filled snack production has been considered and modelled by considering the rheological properties of the different components. The possibility of inserting the filler directly inside the extruder head allows post-extrusion swelling to decrease thus increasing the product quality. To find the optimum position of the filler nozzle with respect to the head extruder orifice, a rheological model was developed by assuming power law behaviour for both dough and filler tangential stresses and a single relaxation time mechanism for the normal stresses shown by dough. The internal swelling was computed numerically for typical industrial conditions and a validation of the model was done by varying around the mass flow rate of dough, the flow indexes of the two components, the consistency index of dough, and finally some geometrical conditions. It was found that the system did not depend too much on the geometry, but is very sensitive to dough and filler rheological properties. The simulation predictions appeared to be in agreement with industrial expectations, predicting a short distance between nozzle and extruder head.

Non-enzymatic browning (NEB) due to the Maillard reaction (MR) was studied in a closed starch/glucose/lysine model system (20 g kg−1 glucose, 10 g kg−1 lysine) in order to analyse conditions favouring reactivity during an industrial process of pasta VHT (very high temperature) thermal treatment. The closed model pastes gave data on the NEB progress during the pasta drying cycle as a function of temperature, time and water activity (aw). Indicators such as headspace CO 2 , optical density and colour showed an increase of MR as the initial aw increased from 0.50 to 0.91. During the initial stages of drying, a combination of high temperatures and high aw led to the most likely conditions for NEB. © 1999 Society of Chemical Industry

The generation of a chain-breaking antioxidant capacity has been analyzed in butter cookies, as a function of the cooking time. A kinetics approach was used, by which the antioxidant capacity of aqueous extracts of cookies was measured in terms of equivalence by weight of a reference antioxidant. A diazo compound was used to generate at constant rate peroxyl radicals, and the reporting reaction was the bleaching of crocin in the presence of these radicals. Results indicated that during the first 20−30 min of cooking, when browning takes place, an antioxidant capacity accounting for up to 5 g of Trolox is produced in 100 g of dried aqueous extracts of the cookies. This result supports the concept that functionally relevant antioxidants are generated by Maillard reaction. Keywords: Maillard reaction; lipid oxidation; free radical scavenger; bakery product

The oxidative stability of borage ( Borago officinalis L.) oils from commercial origin or extracted by different methods (with solvents and supercritical CO 2 ) was determined by the Rancimat method. To delay the oxidative degradation with the aim of preserving the nutritional characteristics of borage oil, several borage—virgin olive oil blends were prepared and submitted to analysis. The results indicated that the incorporation of borage in virgin olive oil (to a level not exceeding 50 g/kg) while modifying the fatty acid profile of the resulting blends had a limited effect on the oxidative stability provided that the blends were maintained in the absence of light.

The goals of the present studies were: (1) to obtain smoking material from tobacco with reduced toxicity; (2) to use the tobacco leaf, as an alternative to other plants, as a source of food protein. On the grounds of technological, nutritional and agronomical results, the following observations can be made: (1) It is feasible to lower the toxicity of the tobacco smoke by extracting protein from the green leaves before curing. (2) The cured deproteinized tobacco can easily be utilized for the production of smoking material without any important alteration of its taste. (3) The composition of the tobacco protein concentrate is very interesting and is superior to other protein concentrates. (4) Itsin vivo andin vitro digestibility is one of the highest among the vegetable protein sources which have been studied. (5) Use of high planting densities and high levels of nitrogen fertilization per hectare results in high yields of total protein from tobacco (1794 Kg/ha).

Summary Fermented crushed Prosecco grapes were distilled using a batch still under normal (100.9 kPa) and reduced pressure (40 or 47 kPa) with and without the rectifying column of the distillation equipment. To improve insight into the behaviour of ethanol and the partitioning of some volatile compounds, each distillate was collected in fractions and analysed for lower volatile alcohols and esters. The results show that the behaviour of ethanol under reduced pressure was more consistent, the proof level higher than at normal pressure and there was a stripping eVect on the volatile compounds considered at low pressure. This eVect is enhanced when the rectifying column is included. It was concluded that it could be advantageous to use ‘vacuum distillation’ because it simpliWes the operation of the equipment and leads to an overall reduction of the heating required, although there are problems of losses of desirable aromatic compounds.

Mayonnaises are oil in water emulsions with a texture that is particularly appreciated by consumers. The actual nutritional trend towards low-calorie foods has increased the interest in fat substitutes without altering the consistency of the product. From this point of view rheological properties may give a quantitative contribution to texture characterization and control when using different formulations. The rheological approach has been applied to typical commercial normal and light mayonnaises with a fat content ranging from 76 to 48%. These materials have shown a viscoelastic behaviour that was measured by means of both oscillatory and creep-recovery tests. The storage modulus, the compliance and the yield stress were found to increase when increasing the fat content. A modified Bolhin theory was used to relate structural parameters to rheological dynamical measurements. Thus the emulsion stability was quantified by means of a pseudoplastic-coordination number (z) and the value of G′ at 1 Hz . From the creep test the value of the yield stress was determined and in the case of the light mayonnaise was very close to a normal emulsion whereas the corresponding viscoelastic properties were very different. This implies that to reproduce an assumed texture, it is necessary to perform all the tests outlined.

Poly(lactic acid) (PLA) is a biodegradable and renewable polyester, which is considered as the most promising eco-friendly substitute of conventional plastics. It is mainly used for food packaging applications, but some drawbacks still reduce its applications. On the one hand, its low barrier performance to gases (e.g. O2 and CO2) limits its use for applications requiring low gas transfer, such as modified atmosphere packaging (MAP) or for carbonate beverage packaging. On the other hand, its natural water sensitivity, which contributes to its biodegradation, limits its use for high moisture foods with long shelf life.Other biopolymers such as wheat gluten (WG) can be considered as interesting materials able to increase the PLA performances. WG is much more water sensitive, but it displays better gas barrier properties in dry surroundings. This complementarity in barrier performances drove us to study the development of multilayer complexes PLA-WG-PLA and to open unexplored application scenarios for these biopolymers.This project was thus intended to better understand how food components and use conditions could affect the performances of PLA films, and how these performances could be optimized by additional processing such as surface modifications (e.g. corona treatment and coatings).To that aim, three objectives were targeted:-To study the stability of industrially scale produced PLA films in contact with different molecules (CO2 and water) and in contact with vapour or liquid phases, with different pH, in order to mimic a wide range of food packaging applications.-To better understand the impact of some industrial processes such as corona or hot press treatments on PLA.-To combine PLA with WG layer to produce high barrier and biodegradable complexes.Different approaches coming from food engineering and material engineering were adopted. PLA films were produced at industrial scale by Taghleef Industries with specific surface treatments like corona. Wheat gluten films, coatings and layers were developed and optimized at lab scale as well as the 3-layers PLA-WG-PLA complexes. Different technologies able to mimic industrial processes were considered such as hot press, high pressure homogenization, ultrasounds, wet casting and spin coating. The physical and chemical properties of PLA films were then studied at the bulk and surface levels, from macroscopic to nanometer scale. The functional properties like permeability to gases (e.g. O2 and CO2) and water, gas and vapour sorption, mechanical and surface properties were also investigated.Exposed to CO2, PLA films exhibited a linear sorption behaviour with pressure, but the physical modifications induced by high pressure did not affect its use for food packaging. However, when exposed to moisture in both liquid and vapour state (i.e. environments from 50 to 100 % relative humidity (RH)), PLA was significantly degraded after two months at 50 °C (accelerated test) due to hydrolysis. This chemical deterioration was evidenced by a significant decrease of the molecular weight, which consequently induced a loss of transparency and an increase of the crystallinity. The hydrolysis was accelerated when the chemical potential of water was increased, and it was surprisingly higher for vapour compared to liquid state. In addition, pH did not affect the rate of hydrolysis.Knowing much better the limitation of PLA films, the challenge was to improve its functional properties by combining them with WG, as a high gas barrier bio-sourced and biodegradable polymer. The use of high pressure homogenization produced homogeneous WG coatings, with improved performances. This process was thus selected for making 3 layer complexes by assembly of a wheat gluten layer between two layers of PLA, together with corona treatment and hot press technologies.Corona treatment applied to PLA physically and chemically modified its surface at the nanometer scale (...), Los materiales plásticos tradicionales son utilizados en todos los campos de nuestra vida y en particular modo como embajales de productos alimenticios; los cuales después de ser utilizados contaminan y dañan nuesto medio ambiente. Materiales plásticos derivados de recursos naturales y biodegradables, como el ácido poliláctico (PLA) se encuentran actualmente disponibles en el mercado a pesar de sus menores performances. Este proyecto de doctorado está orientado 1) al estudio de la estabilidad de películas de PLA bajo diferentes condiciones como temperatura, humedad relativa, pH o exposición a vapores o gases, 2) comprender los efectos en las propiedades de las películas de PLA de algunos procesos industriales como el tratamiento corona y hot press, 3) desarrollar complejos multicapas de PLA y gluten que tengan propiedades barrera mejores que las de las películas individuales.Los embalajes a base de PLA han sido producidos por Taghleef Industries, productor líder en el sector y dotado de las infraestructuras industriales adaptadas a los tratamientos superficiales como el tratamiento corona. Las películas de gluten y los coatings han sido desarrollados a escala de laboratorio, así como los complejos tricapa PLA-gluten-PLA.Las propiedades físicas y químicas de las películas de PLA han sido investigadas a nivel de superficie así como a nivel de bulk. Diferentes técnicas de análisis, frecuentemente utilizadas en los campos de las ciencias de los materiales y de las ciencias de los alimentos, han sido empleadas en este proyecto como calorimetría diferencial de barrido (DSC), análisis termogravimétrico (TGA), cromotagrafía de exclusión por tamaño (SEC), microscopía de fuerza atómica (AFM), microscopía electrónica de barrido (SEM), espectroscopía de infrarrojos por transformada de Fourier con reflectancia total atenuada (ATR-FTIR) y espectroscopía fotoelectrónica de rayos X (XPS).Las propiedades funcionales de los embalajes como las permeabilidades al vapor de agua, al oxígeno (O2), al dióxido de carbono (CO2) o al helio (He) han sido investigadas, asi como la absorción de gases/vapores, las propiedades mecánicas y las propiedades superficiales. A pesar de que las películas de PLA absorven linealmente CO2 a presiones mayores, la absorción del gas es reducida a bajas presiones y no modifica las propiedades físicas del PLA, como contrariamente sucede cuando el PLA es expuesto a altas presiones de CO2. Por lo tanto, su influencia en las propiedades funcionales del PLA es mínima en las normales aplicaciones alimentarias. De todos modos cuando los embalajes de PLA son expuestos a ambientes húmedos o cuando son sumergidos en agua, procesos de hidrólisis los degradan significativamente después de dos meses de conservación a 50 °C (test acelerado). Este deterioramiento químico ha sido evidenciado por una significativa reducción del peso molecular del PLA, que en consecuencia induce una pérdida de transparencia y un aumento de su cristalinidad. Además, se ha observado que el pH no influye en la velocidad de hidrólisis. Esta información tiene una importancia práctica para posibles usos del PLA como embalajes de alimentos a alta humedad. El gluten ha sido elegido por sus altas propiedades barrera cuando es protegido de ambientes a alta humedad. La incorporación de lípidos en las películas de gluten no han mejorado sus performances. Pero la tecnología de la homogenización a altas presiones ha permitido mejorar la dispersión del gluten, obteniendo películas más homogéneas y con mejores propiedades funcionales. Esta tecnología ha sido, por lo tanto, elegida para producir los complejos multicapa, intercalando las películas de gluten entre dos de PLA, utilizando el tratamiendo hot press (10 MPa, 130 °C, 10 min) (...), Les plastiques sont aujourd'hui des matériaux ubiquitaires utilisés dans tous les aspects de notre vie quotidienne, en particulier pour l'emballage alimentaire. Cependant, après usage, les plastiques sont une source de pollution de notre environnement naturel. Certains plastiques biodégradables et biosourcés sont déjà disponibles sur le marché, comme l’acide polylactique (PLA), mais ils présentent des performances inférieures. Ce travail de thèse vise à: 1) étudier la stabilité des films de PLA dans diverses conditions de température, d'humidité relative, de pH, d'exposition à des liquides ou à des vapeurs... 2) mieux comprendre l'impact de certains procédés industriels tels que les traitements corona ou pressage à chaud sur le PLA 3) combiner le PLA à des couches de gluten de blé afin de produire des complexes ayant des propriétés barrière plus élevées.Les films de PLA ont été produits par la société Taghleef Industries sur demande et avec des traitements de surface spécifiques, comme le traitement Corona. Des films et des enductions à basede gluten de blé ont été développés à l’échelle laboratoire ainsi que des complexes tricouches PLA- gluten-PLA. Les propriétés physiques et chimiques des films ont été étudiées par différentes techniques issues des sciences des matériaux et des aliments ont été utilisées, telles que l’analyse enthalpique différentielle (DSC), l'analyse thermogravimétrique (TGA), la chromatographie d'exclusion de taille (SEC), la microscopie de force atomique (AFM), la microscopie électronique (SEM), la spectroscopie infrarouge à transformée de Fourier (ATR-FTIR) et la spectroscopie de rayons X (XPS). Les propriétés fonctionnelles telles que la perméabilité à la vapeur d'eau, à l'oxygène (O2), au dioxyde de carbone (CO2) ou à l'hélium (He), la sorption de gaz et de vapeurs, les propriétés mécaniques et de surface ont également été étudiées.Exposés au CO2, les films de PLA présentent une isotherme de sorption linéaire avec l’augmentation de pression. Cependant les modifications physiques et chimiques induites à des pressions élevées n'affectent pas son utilisation dans le domaine d’application alimentaire. Au contraire, lorsque les films de PLA sont exposés à l'humidité à l'état liquide ou vapeur, leur dégradation survient après deux mois à 50 ° C (essai accéléré) suite à son hydrolyse. Cette détérioration chimique, mise en évidence par une diminution significative de la masse molaire, entraine une perte de transparence, mais également par une augmentation de la cristallinité. Par ailleurs, le pH n'affecte pas le taux d'hydrolyse, ce qui est d'un intérêt essentiel pour conditionner des aliments humides.Les films à base gluten de blé ont été choisis pour leurs propriétés de barrière élevées lorsque l’humidité relative reste faible. L'incorporation de lipides n'a pas apporté d'amélioration de leurs performances barrières. Cependant, l'utilisation d’un procédé d’homogénéisation à haute pression a permis une meilleure dispersion du gluten, ce qui a conduit à des films plus homogènes ayant ainsi de meilleures propriétés fonctionnelles. Ces conditions ont donc été retenues pour réaliser des complexes à 3 couches par assemblage d'une couche de gluten de blé entre deux couches de PLA en utilisant un pressage à chaud (10 MPa, 130 ° C, 10 min).La technologie de pressage à chaud montre une forte influence sur les films de PLA, de gluten et sur les tricouches. Elle induit une cristallisation accrue du PLA, ce qui augmente ses propriétés de barrière d'environ 40% et 60%, respectivement pour l'eau et l'oxygène. Cela masque par contre l’effet du traitement corona. D’autre part, le pressage à chaud induit une restructuration du réseau de gluten qui améliore les propriétés de barrière aux gaz des complexes, mais provoque aussi une évaporation de l'eau à l'interface gluten / PLA défavorable à l’adhésion des couches (...), I materiali plastici convenzionali trovano impiego in tutti campi della nostra vita, specialmente nel settore del packaging alimentare, ed in seguito all’utilizzo contaminano e danneggiano il nostro ecosistema. Materiali plastici derivanti da risorse naturali e biodegradabili, come acido polilattico (PLA), sono attualmente disponibili sul mercato anche se caratterizzati da performances inferiori.Questo progetto di dottorato è mirato 1) allo studio della stabilità di film di PLA a varie condizioni di stoccaggio come temperatura, umidità relativa, pH, o esposizione a vapori o gas; 2) a comprendere meglio le influenze di alcuni processi industriali come trattamento corona e hot press nelle proprietà dei film di PLA; 3) a sviluppare complessi multistrato tra film di PLA e di glutine che abbiano proprietà barriera più elevate rispetto ai singoli film.Gli imballaggi a base di PLA sono stati prodotti da Taghleef Industries, produttore leader nel settore e dotato di infrastrutture atte ai trattamenti di modificazione di superfice come il trattamento corona. I film a base di glutine e i coatings sono stati sviluppati e ottimizzati su scala di laboratorio, così come i complessi trilaminari PLA-glutine-PLA.Le proprietà fisiche e chimiche dei film di PLA sono state investigate a livello di superficie, così come a livello di bulk. Diverse tecniche analitiche, provenienti dal campo delle scienze dei materiali e delle scienze degli alimenti, sono state adottate in questo progetto di dottorato come calorimetria differenziale a scansione (DSC), termogravimetria (TGA), cromatografia di esclusione molecolare (SEC), microscopia a forza atomica (AFM), microscopia elettronica a scansione (SEM), spettrofotometria infrarossa a trasformata di Fourier in riflettanza totale attenuata (ATR-FTIR) e spettroscopia fotoelettronica a raggi X (XPS).Le proprietà funzionali come le permeabilità al vapore acqueo (H2O), all’ossigeno (O2), al diossido di carbonio (CO2) o all’elio (He) sono state investigate, cosi come l’assorbimento di gas e/o vapori, le proprietà meccaniche e le proprietà di superfice.Nonostante i film di PLA assorbano linearmente CO2 a pressioni crescenti, l’assorbimento di tale gas è ridotto a basse pressioni in modo da non modificare le sue proprietà fisiche – come contrariamente osservato quando il PLA è esposto a CO2 ad alte pressioni – e da non influenzare negativamente il suo utilizzo come imballaggio alimentare. Ad ogni modo, quando i film di PLA sono esposti ad ambienti umidi, o quando sono immersi in acqua liquida, sono significativamente degradati per idrolisi dopo due mesi di stoccaggio a 50 °C (test accelerato). Questo deterioramento chimico è stato evidenziato da una significativa riduzione del peso molecolare del PLA che, conseguentemente, induce una sua perdita di trasparenza e ne incrementa la sua cristallinità. Inoltre, è stato evidenziato che il pH non influenza la velocità di idrolisi. Quest’informazione ha importanza pratica per possibili utilizzi di PLA come imballaggio di alimenti ad alta umidità.Il glutine è stato scelto per le sue alte proprietà barriera, quando è protetto da ambienti ad alta umidità. Si è visto che l’incorporazione di lipidi non porta con sé grandi miglioramenti nelle performances dei film a base di glutine. Invece, l’utilizzo della tecnologia di omogeneizzazione ad alte pressioni permette una migliore dispersione del glutine, ottenendo film più omogenei e con migliori proprietà funzionali. Questa tecnologia è stata quindi scelta per produrre i complessi multistrato, intercalando i film di glutine tra due film di PLA, usando il trattamento hot press (10 MPa, 130 °C, 10 min). Si è osservato che il trattamento hot press modifica le proprietà dei film di PLA, di glutine e dei film multistrato Hot press induce cristallizzazione in PLA, e conseguentemente aumenta le sue proprietà barriera complessive, approssimativamente al 40 % all’acqua e al 60 % all’ossigeno (...)