Cryptomphalus aspersa Egg Extract Protects against Human Stem Cell Stress-Induced Premature Senescence.

Cellular senescence is a tightly regulated pathophysiologic process and is caused by replicative exhaustion or external stressors. Since naturally derived bioactive compounds with anti-ageing properties have recently captured scientific interest, we analysed the anti-ageing and antioxidant efficacy of Cryptomphalus aspersa egg extract (CAEE). Its effects on stemness, wound-healing properties, antioxidant defense mechanisms, and DNA damage repair ability of Human Wharton's jelly mesenchymal stem cells (WJ-MSCs) were analysed. Our results revealed that CAEE fortifies WJ-MSCs stemness, which possibly ameliorates their wound-healing ability. Additionally, we show that CAEE possesses a strong antioxidant capacity as demonstrated by the elevation of the levels of the basic antioxidant molecule, GSH, and the induction of the NRF2, a major antioxidant regulator. In addition, CAEE alleviated cells' oxidative stress and therefore prevented stress-induced premature senescence (SIPS). Furthermore, we demonstrated that the prevention of SIPS could be mediated via the extract's ability to induce autophagy, as indicated by the elevation of the protein levels of all basic autophagic molecules and the increase in formation of autophagolysosomes in CAEE-treated WJ-MSCs. Moreover, CAEE-treated cells exhibited decreased Caveolin-1 levels. We propose that Cryptomphalus aspersa egg extract comprises bioactive compounds that can demonstrate strong antioxidant/anti-ageing effects by regulating the Caveolin-1-autophagy-senescence molecular axis.

Assessing the emulsifying properties of Tenebrio molitor larvae protein preparations: Impact of storage, thermal, and freeze-thaw treatments on o/w emulsion stability.

Insect proteins have gained attention as novel ingredients, which may contribute to the development of high-value-added products. This study evaluates the emulsifying and emulsion-stabilizing properties of Tenebrio molitor larvae protein preparations obtained through different procedures, leading to the following rich-in-protein samples: ASP (∼67 %), AIP (∼75 %), and SSP (∼62 %). The method applied for protein isolation influenced the molecular and structural characteristics of the preparations, thus affecting their adsorption behaviour at oil-water interfaces and ability to stabilize emulsions. O/w emulsions were prepared, and their physicochemical stability was assessed with respect to droplet size, oil droplet flocculation/coalescence, microstructure, and creaming upon storage as well as after thermal and freeze-thaw treatments. The use of ASP and AIP protein preparation as emulsifiers led to higher stability during storage. All emulsions were stable upon heating and able to withstand two freeze-thaw cycles without phase separation, although there was an increase in droplet size. Interestingly, the AIP emulsion remained stable after the 3rd freeze-thaw cycle, indicating remarkable stability under freezing compared to the other two emulsions. These findings are of great importance for the formulation of food-grade emulsions using insect protein preparations and their future exploitation in developing food items subjected to different treatments.

Characterization of Tenebrio molitor Larvae Protein Preparations Obtained by Different Extraction Approaches.

Edible insects have recently attracted research attention due to their nutritional value and low environmental footprint. Tenebrio molitor larva was the first insect species to be classified by European Food Safety Authority (EFSA) as safe for human consumption. However, it is thought that the incorporation of edible insect as an ingredient in a food product would be more appealing to consumers than being visible. The aim of the present study was to determine the physicochemical properties of the larvae meal and protein concentrates. Different methods to extract and recover proteins from defatted (DF) Tenebrio molitor larvae were applied; i.e., alkaline extraction (DF-ASP); isoelectric precipitation after alkaline extraction (DF-AIP); and NaCl treatment (DF-SSP), and the obtained protein fractions were characterized. The DF-ASP exhibited the highest protein extraction/recovery efficiency (>60%), while it was the most effective in decreasing the interfacial tension at the oil/water (o/w) interface. The DF-AIP had the highest protein content (75.1%) and absolute values of ζ-potential and the best ability to retain water (10.54 g/g) and stabilize emulsions at pH 3.0. The DF-SSP protein preparation had the highest oil binding capacity (8.62%) and solubility (~88%) at acidic pHs and the highest emulsifying activity (~86 m2/g). Electrophoresis of the protein preparations revealed proteins with different molecular weights, while the protein secondary structure was dominated by ß-structures and α-helix. Protein concentrates with different properties were able to be recovered from Tenebrio molitor larvae, that could affect their interactions with other food ingredients and their behavior during processing or storage. These findings would be valuable guidance for the technological exploitation of larvae protein preparations in the development of food formulations.

Headspace Solid-Phase Microextraction Followed by Gas Chromatography-Mass Spectrometry as a Powerful Analytical Tool for the Discrimination of Truffle Species According to Their Volatiles.

This study provides the first assessment of the volatile metabolome map of Tuber Aestivum and Tuber Borchii originating from Greece using headspace solid-phase micro-extraction (HS-SPME) coupled to gas chromatography-mass spectrometry (GC-MS). For the extraction of the volatile fraction, the SPME protocol was optimized after examining the effects of sample mass, extraction temperature, and extraction time using the one-variable at-a-time approach (OVAT). The optimum parameters involved the extraction of 100 mg of homogenized truffle for 45 min at 50°C. Overall, 19 truffle samples were analyzed, and the acquired data were normalized and further processed with chemometrics. Agglomerative hierarchical clustering (HCA) was used to identify the groups of the two species. Partial least squares-discriminant analysis (PLS-DA) was employed to develop a chemometric model that could discriminate the truffles according to the species and reveal characteristic volatile markers for Tuber Aestivum and Tuber Borchii grown in Greece.

Characterization of Oregano Essential Oil (Origanum vulgare L. subsp. hirtum) Particles Produced by the Novel Nano Spray Drying Technique.

Oregano essential oil (OEO), due to its wide variety of biological activities, could be a "green" alternative to chemical preservatives. On the other hand, the difficulties in its use or storage have turned researchers' interest in encapsulation strategies as a way to face stability and handling issues. Fabrication of OEO-loaded particles, using nano spray drying technique (NSD) and whey protein isolate-maltodextrin mixtures (1:1, 1:3) as wall materials appears to be a novel and promising strategy. The obtained particles were characterized in terms of volatile composition, encapsulation efficiency, and physicochemical, molecular, morphological, and antibacterial properties. The results confirmed that encapsulation of OEO using NSD achieved high levels of powder recovery (>77%) and encapsulation efficiency (>98%) while assisting in the retention of the main bioactive compounds. The partial replacement of WPI by MD significantly affected particles' physical properties. FTIR analyses revealed the possible structural stabilization of core and wall materials, while SEM verified the very fine size and spherical shape. Finally, antibacterial studies demonstrated their activity against Escherichia coli and Staphylococcus aureus, which is much stronger in comparison with that of pure OEO, proving the positive effect of NSD and particles' potential in future food applications.

Single Origin Coffee Aroma: From Optimized Flavor Protocols and Coffee Customization to Instrumental Volatile Characterization and Chemometrics.

In this study, the aroma profile of 10 single origin Arabica coffees originating from eight different growing locations, from Central America to Indonesia, was analyzed using Headspace SPME-GC-MS as the analytical method. Their roasting was performed under temperature-time conditions, customized for each sample to reach specific sensory brew characteristics in an attempt to underline the customization of roast profiles and implementation of separate roastings followed by subsequent blending as a means to tailor cup quality. A total of 138 volatile compounds were identified in all coffee samples, mainly furan (~24-41%) and pyrazine (~25-39%) derivatives, many of which are recognized as coffee key odorants, while the main formation mechanism was the Maillard reaction. Volatile compounds' composition data were also chemometrically processed using the HCA Heatmap, PCA and HCA aiming to explore if they meet the expected aroma quality attributes and if they can be an indicator of coffee origin. The desired brew characteristics of the samples were satisfactorily captured from the volatile compounds formed, contributing to the aroma potential of each sample. Furthermore, the volatile compounds presented a strong variation with the applied roasting conditions, meaning lighter roasted samples were efficiently differentiated from darker roasted samples, while roasting degree exceeded the geographical origin of the coffee. The coffee samples were distinguished into two groups, with the first two PCs accounting for 73.66% of the total variation, attributed mainly to the presence of higher quantities of furans and pyrazines, as well as to other chemical classes (e.g., dihydrofuranone and phenol derivatives), while HCA confirmed the above results rendering roasting conditions as the underlying criterion for differentiation.

Exploring the volatile metabolome of conventional and organic walnut oils by solid-phase microextraction and analysis by GC-MS combined with chemometrics.

It is challenging to establish a correlation between the agronomical practices and the volatile profile of high-value agricultural products. In this study, the volatile metabolome of walnut oils from conventional and organic farming type was explored by HS-SPME-GC-MS. The SPME protocol was optimized after evaluating the effects of extraction time, extraction temperature, and sample mass. The optimum parameters involved the extraction of 0.500 g walnut oil at 40 °C within 60 min. Twenty Greek walnut oils produced with conventional and organic farming were analyzed and 41 volatile compounds were identified. The determined compounds were semi-quantified, and further processed with chemometrics. Agglomerative hierarchical clustering (AHC) and principal component analysis (PCA) were used. A robust classification model was developed using sparse partial least squares-discriminant analysis (sPLS-DA) for the discrimination of walnut oils into conventional and organic, establishing volatile markers that could be used to guarantee the type of farming.

Complex coacervate formation between hemp protein isolate and gum Arabic: Formulation and characterization.

In this study, intermolecular interactions and structure formation between hemp protein isolate (HPI) and gum Arabic (GA) were investigated to unravel their complexation mechanisms. For this purpose, structural transition as a function of pH (2.0-7.0) and protein to polysaccharide ratio (HPI:GA, R = 0.5:1-13:1 w/w) was evaluated via turbidimetric analysis, ζ-potentiometry, state diagram construction and coacervate yield. It was proved that critical phase transition pH shifted to higher values with R increase, until reaching a plateau at ratio 10:1, with complexes to be formed even at pH region where both biopolymers were negatively charged. The shift of pH value, where maximum turbidity was noticed (pHopt), was well in accordance with net charge neutrality of HPI-GA mixtures found by electrophoretic mobility measurements. Maximum coacervation, occurred at ratio R = 2:1 and pHopt = 3.5, was depicted by the highest yield (92%), while morphological characteristics of liquid as well as freeze-dried HPI-GA coacervates, obtained through optical and scanning electron microscope measurements, gave a further perception of the associative processes during complex coacervation. Additionally, the molecular interactions between HPI and GA were confirmed by Fourier transform infrared spectroscopy (FTIR) revealing primarily electrostatic interactions with secondary stabilization of hydrogen bonds. Therefore, these findings could provide useful information for the development of HPI - GA coacervates as a potential bioactive encapsulation means.

Synthesis of D-Limonene Loaded Polymeric Nanoparticles with Enhanced Antimicrobial Properties for Potential Application in Food Packaging.

Mini-emulsion polymerization was applied for the synthesis of cross-linked polymeric nanoparticles comprised of methyl methacrylate (MMA) and Triethylene Glycol Dimethacrylate (TEGDMA) copolymers, used as matrix-carriers for hosting D-limonene. D-limonene was selected as a model essential oil, well known for its pleasant odor and its enhanced antimicrobial properties. The synthesized particles were assessed for their morphology and geometric characteristics by Dynamic Light Scattering (DLS) and Scanning Electron Microscopy (SEM), which revealed the formation of particles with mean diameters at the nanoscale (D[3,2] = 0.135 µm), with a spherical shape, while the dried particles formed larger clusters of several microns (D[3,2] = 80.69 µm). The percentage of the loaded D-limonene was quantified by Thermogravimetric Analysis (TGA), complemented by Gas Chromatography-Mass Spectrometry analysis coupled with a pyrolysis unit (Py/GC-MS). The results showed that the volatiles emitted by the nanoparticles were composed mainly of D-limonene (10% w/w of dry particles). Particles subjected to higher temperatures tended to decompose. The mechanism that governs the release of D-limonene from the as-synthesized particles was studied by fitting mathematical models to the release data obtained by isothermal TGA analysis of the dry particles subjected to accelerated conditions. The analysis revealed a two-stage release of the volatiles, one governed by D-limonene release and the other governed by TEGDMA release. Finally, the antimicrobial potency of the D-limonene-loaded particles was demonstrated, indicating the successful synthesis of polymeric nanoparticles loaded with D-limonene, owing to enhanced antimicrobial properties. The overall performance of these nanoparticles renders them a promising candidate material for the formation of self-sterilized surfaces with enhanced antimicrobial activity and potential application in food packaging.

Cake Perception, Texture and Aroma Profile as Affected by Wheat Flour and Cocoa Replacement with Carob Flour.

Carob flour has been used in the production of a wide range of functional food formulations such as bakery goods either as a natural sweetener or food ingredient that, when roasted, exerts a chocolate/cocoa-reminiscent flavor and color. The aim of the present study was twofold; firstly to study the effect of an increasing incorporation of roasted carob flour (0-70% flour basis) on the quality and sensory attributes of a conventional cocoa cake recipe and secondly to investigate the obtained volatile fraction responsible for the aroma by means of headspace solid phase microextraction (HS-SPME) technique coupled to gas chromatography/mass spectrometry (GC/MS) while comparing it with the control, cocoa-containing cake recipe. Thirty and fifty percent carob flour incorporation rendered cakes with acceptable texture and sensory attributes, comparable to the control cake recipe containing 20% cocoa. Similarity to cocoa aroma was attributed to a great number of odor active compounds mainly belonging to aldehydes, lactones, furan/pyran derivatives, and pyrrole derivatives.

Biscuits Enriched with Dietary Fibre Powder Obtained from the Water-Extraction Residue of Maize Milling by-Product.

A maize milling by-product was defatted by aqueous extraction and the residue was dehydrated, comminuted and sieved to obtain two powders differing in particle size and having a very high fibre content. The powders were then incorporated into the structure of short-dough biscuit, at two wheat flour substitution levels (10 and 20%), aiming at the development of a nutritionally improved product. Their impact on biscuit dough properties and the quality and sensory characteristics of the final products was evaluated. As it was revealed, powders' addition altered dough consistency and alveograph indices mainly due to interactions between wheat flour proteins and polysaccharides and enhanced the nutritional profile of the biscuits by inducing a 4- to 6-fold increase of their fibre content. Additionally, it influenced only to a limited extent the degree of some of the final product characteristics, e.g., protein and fat content, spread ratio, breaking strength, depending both on the level of incorporation and the particle size of the residue. On the whole, products' sensory quality was not negatively influenced, suggesting that it is possible to use both powders for the fortification with fibre of biscuits and possibly other bakery products.

Exploitation of hazelnut, maize germ and sesame seed aqueous extraction residues in the stabilisation of sesame seed paste (tahini).

BACKGROUND: Sesame seed paste is a highly nutritious food product which, upon long-term storage, tends to exhibit undesirable phenomena of oiling-off and particle sedimentation. The ability of rich-in-fibre aqueous extraction powders originating from oleaginous raw materials to enhance the physical stability of sesame paste is investigated in this study. RESULTS: The extraction residues remaining after treating hazelnut, sesame seed or maize germ with aqueous media in order to extract and exploit their oil bodies, were collected, dehydrated and milled into fine powders. The powders were then incorporated at various levels into a commercially available sesame paste product to assess their potential as paste stabilisers against oil separation. The solids from maize germ exhibited the highest stabilising ability followed by the solids from hazelnut. In contrast, the solids originating from the sesame seed were less effective in stabilising the sesame paste. Shear stress-rate of shear measurements of sesame paste incorporating the extraction residue solids were conducted in an attempt to explain the different stabilising behaviour of the three powders. CONCLUSION: The intensity of interactions between the incorporated solids within the sesame paste structure may determine the rheological properties of the blend and hence its stability against oiling-off upon long-term storage. © 2016 Society of Chemical Industry.

Process engineering for bioflavour production with metabolically active yeasts - a mini-review.

Flavours are biologically active molecules of large commercial interest in the food, cosmetics, detergent and pharmaceutical industries. The production of flavours can take place by either extraction from plant materials, chemical synthesis, biological conversion of precursor molecules or de novo biosynthesis. The latter alternatives are gaining importance through the rapidly growing fields of systems biology and metabolic engineering, giving efficient production hosts for the so-called 'bioflavours', which are natural flavour and/or fragrance compounds obtained with cell factories or enzymatic systems. Yeasts are potential production hosts for bioflavours. In this mini-review, we give an overview of bioflavour production in yeasts from the process-engineering perspective. Two specific examples, production of 2-phenylethanol and vanillin, are used to illustrate the process challenges and strategies used.

Bioflavour production from orange peel hydrolysate using immobilized Saccharomyces cerevisiae.

The rising trend of bioflavour synthesis by microorganisms is hindered by the high manufacturing costs, partially attributed to the cost of the starting material. To overcome this limitation, in the present study, dilute-acid hydrolysate of orange peel was employed as a low-cost, rich in fermentable sugars substrate for the production of flavour-active compounds by Saccharomyces cerevisiae. With this purpose, the use of immobilized cell technology to protect cells against the various inhibitory compounds present in the hydrolysate was evaluated with regard to yeast viability, carbon and nitrogen consumption and cell ability to produce flavour active compounds. For cell immobilization the encapsulation in Ca alginate beads was used. The results were compared with those obtained using free-cell system. Based on the data obtained immobilized cells showed better growth performance and increased ability for de novo synthesis of volatile esters of "fruity" aroma (phenylethyl acetate, ethyl hexanoate, octanoate, decanoate and dodecanoate) than those of free cells. The potential for in situ production of new formulations containing flavour-active compounds derive from yeast cells and also from essential oil of orange peel (limonene, α-terpineol) was demonstrated by the fact that bioflavour mixture was found to accumulate within the beads. Furthermore, the ability of the immobilized yeast to perform efficiently repeated batch fermentations of orange peel hydrolysate for bioflavour production was successfully maintained after six consecutive cycles of a total period of 240 h.