1,720,965 research outputs found
Analysis of the effect of recent reformulation strategies on the crystallization behaviour of cocoa butter and the structural properties of chocolate
Get PDFChocolate is a complex soft material characterized by solid particles (cocoa powder, milk solid particles and sugar crystals) dispersed in a crystallized fat matrix mostly composed of cocoa butter (CB). Important chocolate properties such as snap, and visual appearance are strongly dependent on the internal molecular arrangement (polymorph), size and shape, as well as the spatial distribution of CB crystals within the chocolate mix. In recent years confectionary companies have put increasing effort in developing novel chocolate recipes to improve the nutritional profile of chocolate products (e.g., by reducing the amount of high saturated fat and sugar content) and to counteract the increasing price of cocoa butter as well as sustainability issues related to some chocolate ingredients. Different reformulation strategies can dramatically affect the crystallization thermodynamic and kinetic behaviour of cocoa butter; therefore, affecting the structural and sensorial properties of chocolate. In this review we analyse how different reformulation strategies affect the crystallization behaviour of cocoa butter and, hence, the structural and sensorial properties of chocolate. In particular, this work discusses the effect of: (1) CB replacement with emulsions, hydrogels, oleogels and oleofoams; (2) CB dilution with limonene or cocoa butter equivalents; (3) replacement or reduction of the amount of sugar and milk in chocolate. We found that there is certainly potential for successful novel alternative chocolate products with controlled crystalline properties; however, further research is still needed to ensure sensory acceptance and reasonable shelf-life of these novel products
Real-time monitoring of fat crystallization using pulsed acoustic spectroscopy and supervised machine learning
Get PDFEnhancing the control and yield of lipid crystallization is fundamental in several industrial areas, including pharmaceutical, cosmetic and food manufacturing. However, the multi-component nature of fats and oils poses a challenge in the understanding and control of the final product properties. While the crystallization of lipid has been extensively studied with offline techniques, online monitoring of the process would be highly advantageous, especially in large-scale sheared vessels. In this work, a novel method to calculate the solid fat content (SFC%) of crystallizing lipids under shear, based on an acoustic probe and supervised-machine learning, is presented. The temperature, composition and ultrasonic velocity of the samples, and the SFC(%) measured with nuclear magnetic resonance were used to develop a predictive model to calculate the SFC(%) during crystallization. Gaussian models showed the highest accuracy compared to linear and regression tree models (RMSE = 0.03 vs 0.7 and 0.25, respectively)
The Effect of Crystallization Conditions on the Structural Properties of Oleofoams Made of Cocoa Butter Crystals and High Oleic Sunflower Oil
No full textEdible air-in-oil systems, also referred to as oleofoams, constitute a novel promising material for healthier, low-calorie fat replacers in confectionary products. Oleofoams can be formed by whipping oleogels, which are dispersions of fat crystals in an oil phase. Understanding how the properties of the fat crystals (i.e., size, shape, and polymorphism) contained in oleogels affect the microstructure and stability of oleofoams is essential for both the efficient design and manufacture of novel food products. In this work, cocoa butter, one of the main fat phases present in confectionary productions, which is responsible for pleasant texture and mouthfeel properties, was mixed with high oleic sunflower oil and crystallized to obtain an oleogel. This was subsequently whipped to yield a stable, highly aerated oleofoam. The effect of the crystallization conditions (oleogel composition and cooling rate) on the properties of the oleogels and related oleofoams was investigated with a multitechnique characterization approach, featuring polarized light microscopy, cryogenic scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, and oscillatory rheology. Oleogel crystallization was performed in a lab-scale vessel and was monitored using light turbidimetry as an in situ technique. Results showed that the concentration of cocoa butter in sunflower oil was the parameter that affected most strongly the foamability and rheology of oleofoam samples. The size and shape of cocoa butter crystals within the oleogel was found to have a less significant effect since crystals were broken or partially melted during the aeration process. Oleofoams whipped from oleogels containing 15 and 22% w/w cocoa butter displayed an overrun of 200%, corresponding to a calorific density reduction to one-third, and an increase in both the elastic and viscous moduli compared to their oleogel precursor. This was explained by a structuring effect caused by the aeration process, where cocoa butter β(V) crystal nanoplatelets (CNPs) in the oleogel rearranged to stabilize the air bubbles via a Pickering mechanism. Oleofoams prepared from 30% w/w cocoa butter oleogels, on the other hand, incorporated less air (overrun between 150 and 180%) and displayed a similar viscoelastic profile to their unwhipped precursors potentially due to air incorporation being limited by the relatively high elastic modulus of the parent oleogels. Nevertheless, the calorific density of these samples was reduced by a factor of 1.6-2.5 compared to their full-fat analogues
Latest advances in imaging techniques for characterizing soft, multiphasic food materials
No full textOver the last two decades, the development and production of innovative, customer-tailored food products with enhanced health benefits have seen major advances. However, the manufacture of edible materials with tuned physical and organoleptic properties requires a good knowledge of food microstructure and its relationship to the macroscopic properties of the final food product. Food products are complex materials, often consisting of multiple phases. Furthermore, each phase usually contains a variety of biological macromolecules, such as carbohydrates, proteins and lipids, as well as water droplets and gas bubbles. Micronutrients, such as vitamins and minerals, might also play an important role in determining and engineering food microstructure. Considering this complexity, highly advanced physio-chemical techniques are required for characterizing the microstructure of food systems prior to, during and after processing. Fast, in situ techniques are also essential for industrial applications. Due to the wide variety of instruments and methods, the scope of this paper is focused only on the latest advances of selected food characterization techniques, with emphasis on soft, multi-phasic food materials
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
