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Honey is a highly viscous sugar solution, often supersaturated, that is susceptible to time dependent crystallization (1). For most commercial honeys, crystallization is a defect that causes quality loss due to phase separation, sedimentation and increase in water activity. On the other hand, controlled crystallization can be used to obtain a desirable product, such as creamed (or set) honey, in which there are a large number of crystals of very small size, that lead to a very smooth texture (2). The aim of this research was to evaluate the physical and structural properties of creamed honey obtained by controlled crystallization compared to honey set in a traditional static manner.

The macroscopic properties of oily food dispersions, such as rheology, mechanical strength, sensory attributes (e.g. mouth feel, texture and even flavour release) and as well as engineering properties are strongly determined by their microstructure, that is considered a key parameter in the understanding of the foods behaviour . In particular the rheological properties of these matrices are largely influenced by their processing techniques, particle size distribution and composition of ingredients. During chocolate manufacturing, mixtures of sugar, cocoa and fat are heated, cooled, pressurized and refined. These steps not only affect particle size reduction, but also break agglomerates and distribute lipid and lecithin-coated particles through the continuous phase, this considerably modify the microstructure of final chocolate. The interactions between the suspended particles and the continuous phase provide information about the existing network and consequently can be associated to the properties and characteristics of the final dispersions. Moreover since the macroscopic properties of food materials, are strongly determined by their microstructure, the evaluation and study of the microstructural characteristics, can be very important for a through understanding of the food matrices characteristics and to get detailed information on their complexity. The aim of this study was investigate the influence of formulation and each process step on the microstructural properties of: chocolate type model systems, dark milk and white chocolate types, and cocoa creams. At the same time the relationships between microstructural changes and the resulting physico-chemical properties of: chocolate type dispersions model systems dark milk and white chocolate were investigated., Le proprietà macroscopiche di dispersioni alimentari a base oleosa tra cui quelle reologiche, meccaniche e sensoriali (consistenza, texture, palatabilità, viscosità, stabilità fisica, ecc.) sono fortemente influenzate dalla loro microstruttura che è considerata un parametro chiave nella comprensione del “comportamento macroscopico” degli alimenti. In particolar modo le proprietà reologiche di tali matrici alimentari sono direttamente influenzate sia dalla formulazione che dal processo di produzione. Durante la produzione di cioccolato e/o surrogati a base di cacao, miscele di zucchero, cacao e grassi vengono riscaldate, raffreddate, pressurizzate e raffinate (Beckett 2000). Questi operazioni tecnologiche la contribuiscono a ridurre la dimensione delle particelle, a rompere gli agglomerati e a distribuire grassi e lecitina attorno alle singole particelle, modificandone la loro microstruttura . Poiché le proprietà macroscopiche di tali matrici alimentari sono fortemente determinate dalla loro microstruttura, la valutazione delle caratteristiche microstrutturali risulta essere molto importante al fine di studiare e ottenere dettagliate informazioni sulla loro complessità. Il presente studio si è proposto pertanto di valutare, mediante tecniche dirette di microscopia ed indirette di laser light diffraction, l’influenza delle diverse formulazioni e di ogni singola fase del processo produttivo sulle proprietà microstrutturali di: sistemi modello a base oleosa, cioccolato fondente, al latte e bianco e surrogati a base di cacao. Parallelamente sono state investigate le relazioni esistenti tra le caratteristiche micro strutturali delle suddette matrici e le loro proprietà reologiche e chimico-fisiche.

The effect of different process stages on microstructural and visual properties of dark chocolate was studied. Samples were obtained at each phase of the manufacture process: mixing, prerefining, refining, conching, and tempering. A laser light diffraction technique and environmental scanning electron microscopy (ESEM) were used to study the particle size distribution (PSD) and to analyze modifications in the network structure. Moreover, colorimetric analyses (L*, h°, and C*) were performed on all samples. Each stage influenced in stronger way the microstructural characteristic of products and above all the PSD. Sauter diameter (D [3.2]) decreased from 5.44 μm of mixed chocolate sample to 3.83 μm, of the refined one. ESEM analysis also revealed wide variations in the network structure of samples during the process, with an increase of the aggregation and contact point between particles from mixing to refining stage. Samples obtained from the conching and tempering were characterized by small PS, and a less dense aggregate structure. From color results, samples with the finest particles, having larger specific surface area and the smallest diameter, appeared lighter and more saturated than those with coarse particles. © 2014 Institute of Food Technologists®.

The aim of this research was to investigate the influence of different process steps on microstructural, rheological and calorimetric properties of dark chocolate. Samples were obtained at each phase of the manufacturing process: mixing, pre-refining, refining, conching and tempering. Microstructural properties, fundamental rheological parameters (yield stress, apparent viscosity, G’ and G”) and thermal ones (Tonset, Tend and ΔH) were evaluated by using an environmental scanning electron microscope (ESEM), a controlled strain – stress rheometer and a differential scanning calorimetry (DSC) respectively. ESEM analysis revealed an increase of the aggregation and contact point between particles from mixing to refining step, that underwent a drastic raising of all considered rheological (yield stress, apparent viscosity, G’, G’’) and thermal parameters (Tonset, Tend, ΔH). Samples obtained from the conching and tempering steps were characterized by less dense aggregate structure and lower particle–particle interactions, due to the adding of further cocoa butter and lecithin. The addition of fat and lecithin in fact covering the sugar and cocoa particles, reduced interactions and caused a decrease in all rheological and thermal parameters.

The effects of different types (fractionated palm oil and hydrogenated fats – HFs) and amounts of fats on the rheological and textural properties of laboratory made nut creams were evaluated. Samples were produced in a roller ball mill pilot plant, and the color, rheological and textural characteristics were evaluated. Experimental creams were compared with two commercial ones. The highest amount of HFs led to an increase of consistency, viscosity and elasticity of creams involving a reduction in colorimetric parameters compared to ones with or without a low level of HFs. Finally, the potential interchangeability between fundamental and empirical measurements was demonstrated

The rheology study of complex systems made up from different solid particles dispersed in a continuous fluid, such as nut creams, is important because it is related to the efficiency of the main process steps and to the quality, stability and sensorial characteristics of final products. In particular formulation and the used ingredients become key parameters that can affect strongly their rheological properties. The effects of different types (palm oil and hydrogenated fats - HF) and amounts of fats, on the rheological and textural properties of laboratory made nut creams were evaluated. The creams were produced in roller ball mill pilot plant, and colour (hue angle, Chroma), rheological (steady and dynamic measurements) and textural (back extrusion test) characteristics were evaluated. The experimental nut creams were compared with two commercial ones. The highest amounts of HFs (50%) led to an increase of consistency, viscosity and elasticity of creams compared to ones without or with low level of HFs (25%), probably due to the presence of strongly fat networks that implies more aggregated structure. In particular, among the experimental creams, sample having in formulation 75% of palm oil and 25% of HFs showed fundamental (G’’ and K index) and textural properties similar to the commercial cream leader of market. Moreover it was found that the increase of HFs quantity in creams involves a reduction in hue angle and chroma values. Finally, both fundamental and empirical considered parameters resulted to be equally useful and sensitive in discriminate rheological properties of the different cream samples.

The effects of heat-transfer modes on acrylamide (AA), AA precursors, and the main quality characteristics of biscuits were investigated. Biscuits were baked in ventilated mode (V), with forced air convection, and static mode (S), based only on conduction, at 175 °C for 18, 20, 22, 24, 26 min. Both heat-transfer types promoted an increase in AA levels during baking. However, in the V mode the heat was distributed more evenly compared to the S one, causing a faster rise of temperature, as showed by recorded time-temperature profiles. As a consequence, the V biscuits reached higher AA levels compared to those baked under S conditions at 20 and 22 min. Both samples baked at 20 and 22 min in S mode were acceptable based on the results of quality parameters. Nevertheless, under the formulation and baking conditions applied, all samples showed AA levels below the reference value of Commission Regulation (EU) 2017/2158.

The melting profile of solid fat content (SFC) is an important parameter for many fat-based food products, such as solid matrices, emulsions, and dispersions, since it can provide essential information on product stability, physical appearance, spreadability, mouthfeeling, particles adsorption and coalescence, and on the release of compounds in the encapsulation technology. The current standard techniques to measure SFC, namely, pulsed nuclear magnetic resonance and differential scanning calorimetry (DSC), provide accurate results but require expensive instrumentation and trained personnel. On the other hand, techniques are needed for fast, in situ measurements by generic operators along production lines to control industrial processes. In this paper, a novel technique to measure SFC in vegetable fats and oils is presented that could be implemented in the form of a low-cost, portable electronic system. The method is based on single-wavelength (835 nm) optical measurements during a thermal cycle of the sample under test. The experimental results obtained with such a method are in good/excellent agreement with those provided by DSC ( $R^{2} > 0.9$ ), thus indicating that the proposed technique could represent the basis for practical analysis in production environment, in order to evaluate the quality and the properties of liquid and solid fat food materials.

The aim of this work was to evaluate the effect of two different cocoa-based coatings on some quality characteristics of fresh-cut fruits (grape and apple) during storage. Apples were cut into small pieces before application of cocoa coatings, while for grapes whole berries were used. Fruit samples were immersed in the cocoa dipping to obtain a thin layer of coating and then left to solidify. Coated products were packed in polyethylene terephthalate (PET) trays under atmospheric conditions and stored for 10 days at 6 °C and analysed at 0, 2, 4, 6, 8, 10 days for water activity, moisture, colour, texture, cell viability, microbiological and sensorial quality. Cocoa coatings provided positive effects on sensory properties of analysed fruit samples during storage. In general, coated grapes maintained better quality and microbiological characteristics compared to coated apple samples and uncoated ones showed general better performances mainly in terms of firmness and microbiological spoilage. All coated samples showed a shelf-life similar to uncoated ones, in particular from a microbiological point of view, generally until the 3rd day of storage for apples and the 6th day for grapes. Moreover, coating B showed better performances compared to A in enhancement of the shelf-life of fruits.

The effect of partial replacement of wheat flour with soy paste and wheat fiber on rheological, textural, physicochemical, and organoleptic characteristics of an enriched pizza base (E) was investigated in comparison with those of a control pizza base (C). New ingredients (e.g., enriched cooked ham, whey cheese, and tomato sauce realized using food industry by-products) were also used in E pizza topping to further increase its nutritional properties. Enriched dough was developed first at a laboratory level. Large and small deformation, moisture, leavening activity, and metabolic heat were tested. On the final product, produced at the industrial level, textural, color, sensory, and nutritional analyses were performed. Preliminary rheological analysis was essential to evaluate the suitability of the new pizza to be processed at industrial level. Both pizza dough samples showed a solid elastic-like behavior; however, the addition of soy and fiber increased moisture content of E pizza, due to the water binding ability of soy protein and to the effect of fibers that also decreased E dough elasticity. No differences in extensibility between the two samples were observed, whereas significantly lower values of resistance to extension and dough force were shown in sample E. These differences were likely due to the presence of soy that interfere with gluten formation and to the dietary fibers that interact with water. Ingredients used in E pizza improved its nutritional quality increasing dietary fibers and protein, and decreasing saturated fatty acids and cholesterol content, which contributed to decrease energy value, in terms of kilocalorie reduction. Practical applications In this work, the effects of using new ingredients (e.g., soy paste, wheat fiber) on the rheological, textural, physicochemical, nutritional, and organoleptic characteristics of an enriched pizza type were investigated both at laboratory and industrial levels. The new pizza provides a product that combines solid technological performances, in terms of rheological properties and dough elasticity, with improved and balanced nutritional quality, thanks also to the ingredients used in the topping. Results demonstrate the possibility of obtaining new pizza products characterized by nutritional and sensorial properties tailored for different group of consumers.

This study demonstrated the role of buckwheat flour in improving phenolic compounds in white wheat bread. Three bread samples were obtained by using different buckwheat levels (10, 20 and 30%) in formulations. HPLC-ESI-MS was used to detect the presence of free and bound phenolic compounds in bread loaf, crust and crumb. The phenolic profile changed thanks to the addition of buckwheat flour; in fact, flavan-3-ols and flavonols compounds (i.e. rutin, catechin, etc.) were identified in enriched buckwheat. As expected, the phenolic content increased proportionally to buckwheat flour quantity in bread formulations. The total free phenolic amounts ranged from 109 to 235 mg/kg d.w. in control bread and 30% enriched buckwheat bread, respectively. Bread crusts showed the highest total free and bound phenolic content; however, flavan-3-ols, flavonols and flavones are more concentrated in crumb than crust. Moreover, enriched breads showed higher in vitro antioxidant properties (evaluated by DPPH and ABTS assays) than control one.

The relationship between the microstructural and rheological properties of white chocolate was studied during the main steps (mixing, pre-refining, refining, conching and tempering) of the manufacturing process. Laser light diffraction and light microscope techniques were used to study the particle size distribution (PSD) and the modifications of the network structure of the samples. Rheological parameters in terms of yield stress, apparent viscosity and thixotropy were evaluated by using a stress-strain controlled rheometer. The Casson and Windhab rheological models, which are widely used for dark and milk chocolate matrices, were used in order to explain better the rheological values obtained from the flow curves. Particle analysis revealed significant changes in the network structure during process. In particular, from the mixed sample to the refined one, a reduction in particle size was found; Sauter (D[3.2]) and Feret diameters decreased, the former from 18.6 to 6.67 μm and the latter from 320 to 33 μm. Consequently, an increase in the matrix aggregation was observed. The white chocolate samples obtained from the conching and tempering steps were characterized by the statistically lowest values of yield stress and apparent viscosity and by the weak structure. Moreover, the samples were well discriminated by both rheological models applied.