Thyme Essential Oil: Uses, Applications and Extraction

Thyme has been used for its medicinal effects for thousands of years. Its culinary and cosmetic applications have impacted the industry not only as a flavour or aroma ingredient but also as an antimicrobial, antioxidant, antitussive, spasmolytic, and antitumoral ingredient, to mention some. The importance of thyme essential oil, extracts, and components (thymol and carvacrol) relies on these technological and physiological functionalities for the food, biotechnology, and pharmaceutical industries, thus increasing its economic impact. Thermal treatments such as hydrodistillation or steam distillation have been performed to obtain thyme essential oil, extracts or components. However, these processing conditions, might affect both the physiological and technological features, mainly due to the high temperatures used during the treatments. Recent research has been focused on the use of alternative extraction processes. Ultrasound or microwave, have been employed to assist the extraction, improving the yield and maintaining the performance of the compounds. A critical insight into the advances in functionality and extraction processes of thyme essential oil, extracts, and main components is described in this chapter

Towards the Development of 3D-Printed Food: A Rheological and Mechanical Approach

Additive manufacturing, or 3D printing, has raised interest in many areas, such as the food industry. In food, 3D printing can be used to personalize nutrition and customize the sensorial characteristics of the final product. The rheological properties of the material are the main parameters that impact the 3D-printing process and are crucial to assuring the printability of formulations, although a clear relationship between these properties and printability has not been studied in depth. In addition, an understanding of the mechanical properties of 3D-printed food is crucial for consumer satisfaction, as they are related to the texture of food products. In 3D-printing technologies, each manufacturing parameter has an impact on the resulting mechanical properties; therefore, a thorough characterization of these parameters is necessary prior to the consumption of any 3D-printed food. This review focuses on the rheological and mechanical properties of printed food materials by exploring cutting-edge research working towards developing printed food for personalized nutrition

Influence of Drying Method on the Composition, Physicochemical Properties, and Prebiotic Potential of Dietary Fibre Concentrates from Fruit Peels

Dietary fibre concentrates (DFC) obtained from fruit and vegetable by-products are powders, mainly obtained by dehydration, used in food formulations to increase nutritional value and to improve functional properties. The modifications of insoluble, soluble, and total dietary fibres (IDF, SDF, and TDF), physicochemical properties (solubility, swelling capacity, water/oil retention capacity, pH, and tapping density), and prebiotic potential of DFC from orange, mango, and prickly pear peels obtained by freeze-drying (FD) and convective hot air-drying (HA) were studied. In vitro faecal fermentation was used to evaluate the short-chain fatty acid (SCFA) production as a prebiotic indicator. TDF in FD orange was 5.5 g·100 g−1 higher than that in the HA sample, whereas HA increased TDF in prickly pear (9.5 g·100 g−1). No differences in fibre composition were observed in mango DFC. The physicochemical properties mostly affected by dehydration treatment were solubility and swelling capacity. HA increased SCFA production in orange peel (48 mmol·g−1 higher) but decreased it in mango and prickly pear (15 and 19 mmol·g−1 lower). Butyrate production of HA orange DFC was comparable to that obtained with the positive control (4.5 mmol·g−1). No production of propionate or butyrate was observed after 6 h fermentation in mango samples, despite the high SDF content (≈20 g·100 g−1). A decrease of the SDF : TDF ratio produced by the drying method improved the SCFA production

Characterization of the Mechanical Properties of FFF Structures and Materials: A Review on the Experimental, Computational and Theoretical Approaches

The increase in accessibility of fused filament fabrication (FFF) machines has inspired the scientific community to work towards the understanding of the structural performance of components fabricated with this technology. Numerous attempts to characterize and to estimate the mechanical properties of structures fabricated with FFF have been reported in the literature. Experimental characterization of printed components has been reported extensively. However, few attempts have been made to predict properties of printed structures with computational models, and a lot less work with analytical approximations. As a result, a thorough review of reported experimental characterization and predictive models is presented with the aim of summarizing applicability and limitations of those approaches. Finally, recommendations on practices for characterizing printed materials are given and areas that deserve further research are proposed

Effective Stiffness of Fused Deposition Modeling Infill Lattice Patterns Made of PLA-Wood Material

Fused deposition modeling (FDM) uses lattice arrangements, known as infill, within the fabricated part. The mechanical properties of parts fabricated via FDM are dependent on these infill patterns, which make their study of great relevance. One of the advantages of FDM is the wide range of materials that can be employed using this technology. Among these, polylactic acid (PLA)-wood has been recently gaining attention as it has become commercially available. In this work, the stiffness of two different lattice structures fabricated from PLA-wood material using FDM are studied: hexagonal and star. Rectangular samples with four different infill densities made of PLA-wood material were fabricated via FDM. Samples were subjected to 3-point bending to characterize the effective stiffness and their sensitivity to shear deformation. Lattice beams proved to be more sensitive to shear deformations, as including the contribution of shear in the apparent stiffness of these arrangements leads to more accurate results. This was evaluated by comparing the effective Young’s modulus characterized from 3-point bending using equations with and without shear inclusion. A longer separation between supports yielded closer results between both models (~41% for the longest separation tested). The effective stiffness as a function of the infill density of both topologies showed similar trends. However, the maximum difference obtained at low densities was the hexagonal topology that was ~60% stiffer, while the lowest difference was obtained at higher densities (star topology being stiffer by ~20%). Results for stiffness of PLA-wood samples were scattered. This was attributed to the defects at the lattice element level inherent to the material employed in this study, confirmed via micro-characterization

In vitro fecal fermentation of high pressure-treated fruit peels used as dietary fiber sources

Fruit by-products are being investigated as non-conventional alternative sources of dietary fiber (DF). High hydrostatic pressure (HHP) treatments have been used to modify DF content as well as its technological and physiological functionality. Orange, mango and prickly pear peels untreated (OU, MU and PPU) and HHP-treated at 600 MPa (OP/55 °C and 20 min, MP/22 °C and 10 min, PPP/55 °C and 10 min) were evaluated. Untreated and treated fruit peels were subjected to fecal in vitro fermentations. The neutral sugar composition and linkage glycosidic positions were related to the production of short chain fatty acids (SCFA) resulting from the fermentation of the materials. After HHP-treatments, changes from multibranched sugars to linear sugars were observed. After 24 h of fermentation, OP yielded the highest amount of SCFA followed by PPU and MP (389.4, 282.0 and 204.6 μmol/10 mg DF, respectively). HHP treatment increased the SCFA concentration of orange and mango peel by 7 and 10.3% respectively, compared with the untreated samples after 24 h of fermentation. The results presented herein suggest that fruit peels could be used as good fermentable fiber sources, because they yielded high amounts of SCFA during in vitro fermentations.This research was supported by Tecnológico de Monterrey (Research Chair Funds GEE 1A01001 and CDB081) and México’s CONACYT Scholarship Program (Grant Nos. 260692 and 205265) and Project CB2014-237271.We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI)Peer reviewe