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1.
J Microsc ; 293(2): 118-131, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38149687

RESUMEN

In this study, transmission electron microscopy (TEM) and cryo-scanning electron microscopy (cryo-SEM) were evaluated for their ability to detect lipid bodies in microalgae. To do so, Phaeodactylum tricornutum and Nannochloropsis oculata cells were harvested in both the mid-exponential and early stationary growth phase. Two different cryo-SEM cutting methods were compared: cryo-planing and freeze-fracturing. The results showed that, despite the longer preparation time, TEM visualisation preceded by cryo-immobilisation allows a clear detection of lipid bodies and is preferable to cryo-SEM. Using freeze-fracturing, lipid bodies were rarely detected. This was only feasible if crystalline layers in the internal structure, most likely related to sterol esters or di-saturated triacylglycerols, were revealed. Furthermore, lipid bodies could not be detected using cryo-planing. Cryo-SEM is also not the preferred technique to recognise other organelles besides lipid bodies, yet it did reveal chloroplasts in both species and filament-containing organelles in cryo-planed Nannochloropsis oculata samples.


Asunto(s)
Microalgas , Gotas Lipídicas , Microscopía Electrónica de Rastreo , Microscopía Electrónica de Transmisión , Microscopía por Crioelectrón/métodos
2.
Food Microbiol ; 109: 104115, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36309429

RESUMEN

Hanseniaspora opuntiae is a commonly found yeast species in naturally fermenting cocoa pulp-bean mass, which needed in-depth investigation. The present study aimed at examining effects of the cocoa isolate H. opuntiae IMDO 040108 as part of three different starter culture mixtures compared with spontaneous fermentation, regarding microbial community, substrate consumption, and metabolite production dynamics, including volatile organic compound (VOC) and phytochemical compositions, as well as compositions of the cocoa beans after fermentation, cocoa liquors, and chocolates. The inoculated H. opuntiae strain was unable to prevail over background yeasts present in the fermenting cocoa pulp-bean mass. It led to under-fermented cocoa beans after four days of fermentation, which was however reflected in higher levels of polyphenols. Cocoa fermentation processes inoculated with a Saccharomyces cerevisiae strain enhanced flavour production during the fermentation and drying steps, which was reflected in richer and more reproducible aroma profiles of the cocoa liquors and chocolates. Sensory analysis of the cocoa liquors and chocolates further demonstrated that S. cerevisiae led to more acidic notes compared to spontaneous fermentation, as a result of an advanced fermentation degree. Finally, different VOC profiles were found in the cocoa beans throughout the whole chocolate production chain, depending on the fermentation process.


Asunto(s)
Cacao , Chocolate , Fabaceae , Compuestos Orgánicos Volátiles , Fermentación , Saccharomyces cerevisiae/metabolismo , Compuestos Orgánicos Volátiles/metabolismo , Cacao/metabolismo
3.
Crit Rev Food Sci Nutr ; 62(20): 5523-5539, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-33605811

RESUMEN

The performance of appropriate instrumental and/or sensory analyses is essential to gain insights into the flavor profile of cocoa products. This three-part review is compiled of an overview of the most commonly used instrumental techniques to study cocoa liquor and chocolate flavor, their perception by a trained panel and the potential relationship between them. Each part is the result of a thorough literature study, principally focusing on the assumptions, features and limitations of these techniques. Reviewing of the literature revealed that cocoa matrix effects and methodology restraints were not always considered when instrumentally analyzing cocoa flavor. With respect to sensory analyses, various studies lacked reporting of accomplished trainings and performance of panelists. Moreover, a discrepancy was noticed in the descriptive flavor lexicon employed. Finally, when linking instrumental and sensory data, linear modeling is regularly applied, which might not always be appropriate. This review paper addresses the challenges associated with flavor assessment, intending to incite researchers to critically study cocoa flavor and apply standardized protocols and procedures.


Asunto(s)
Cacao , Chocolate , Gusto
4.
Plant J ; 103(4): 1477-1489, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32412127

RESUMEN

The architecture of endosperm cell walls in Hordeum vulgare (barley) differs remarkably from that of other grass species and is affected by germination or malting. Here, the cell wall microstructure is investigated using (bio)chemical analyses, cryogenic scanning electron microscopy (cryo-SEM) and confocal laser scanning microscopy (CLSM) as the main techniques. The relative proportions of ß-glucan, arabinoxylan and pectin in cell walls were 61, 34 and 5%, respectively. The average thickness of a single endosperm cell wall was 0.30 µm, as estimated by the cryo-SEM analysis of barley seeds, which was reduced to 0.16 µm after malting. After fluorescent staining, 3D confocal multiphoton microscopy (multiphoton CLSM) imaging revealed the complex cell wall architecture. The endosperm cell wall is composed of a structure in which arabinoxylan and pectin are colocalized on the outside, with ß-glucan depositions on the inside. During germination, arabinoxylan and ß-glucan are hydrolysed, but unlike ß-glucan, arabinoxylan remains present in defined cell walls in malt. Integrating the results, an enhanced model for the endosperm cell walls in barley is proposed.


Asunto(s)
Pared Celular/metabolismo , Endospermo/metabolismo , Hordeum/metabolismo , Pectinas/metabolismo , Xilanos/metabolismo , beta-Glucanos/metabolismo , Pared Celular/ultraestructura , Microscopía por Crioelectrón , Endospermo/ultraestructura , Hordeum/ultraestructura , Microscopía Confocal , Microscopía Electrónica de Rastreo
5.
J Sci Food Agric ; 94(7): 1325-31, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24115134

RESUMEN

BACKGROUND: High oleic sunflower oil (HOSO) and a fatty acid (FA) mixture were inter-esterified in a solvent-free system catalysed by Lipozyme RM IM to produce a cocoa butter equivalent (CBE). The effects of reaction conditions on the percentage of saturate-oleoyl-saturate (SOS) and saturate-saturate-oleoyl (SSO) triacylglycerols (TAGs) were studied. The process was further optimised by response surface methodology. A five-factor response surface design was used to investigate the influences of the five major factors and their mutual relationships. The five factors were substrate ratio (A, FA/HOSO, mol mol⁻¹), enzyme load (B, wt% based on substrates), water content (C, wt% based on substrates), reaction temperature (D,°C) and reaction time (E, in hours) varying at three levels together with two star point levels. RESULTS: The highest yield (59.1% SOS) and lowest acyl migration (2.9% SSO) was obtained at 10% enzyme load, 1% water content, 1:7 substrate mole ratio, 65°C reaction temperature and 6 h reaction time. All the investigated factors except substrate ratio had significant effect on acyl migration. CONCLUSION: The quadratic response models sufficiently described the acidolysis reaction. All parameters had significant effect on the percentage of SOS TAGs. Based on the models, the reaction was optimised to obtain a maximum yield of SOS TAGs.


Asunto(s)
Grasas Insaturadas en la Dieta/metabolismo , Sustitutos de Grasa/metabolismo , Lipasa/metabolismo , Modelos Biológicos , Ácido Oléico/metabolismo , Aceites de Plantas/metabolismo , Triglicéridos/metabolismo , Reactores Biológicos , Cacao/química , Grasas Insaturadas en la Dieta/análisis , Enzimas Inmovilizadas/metabolismo , Esterificación , Sustitutos de Grasa/química , Proteínas Fúngicas/metabolismo , Calor , Isomerismo , Cinética , Ácido Oléico/análisis , Aceites de Plantas/química , Rhizomucor/enzimología , Semillas/química , Estadística como Asunto , Aceite de Girasol , Triglicéridos/química
6.
Spectrochim Acta A Mol Biomol Spectrosc ; 320: 124563, 2024 Nov 05.
Artículo en Inglés | MEDLINE | ID: mdl-38861828

RESUMEN

Terahertz time-domain spectroscopy (THz-TDS) is an emerging optical technique that has potential applications in the characterization of (bio)materials. However, the complicated extraction of optical parameters from multi-layered and optically thin samples is a barrier towards its acceptance by applied scientists. Therefore, the aim of this work is to provide a straightforward approach for the extraction of the THz absorption coefficient and index of refraction profiles of aqueous thin films in a window-sample-window configuration, which is ubiquitous in many laboratories (i.e., sample in a cuvette). A numerical approach-based methodology that accounts for multiple layers, Fabry-Pérot effect, and sample thickness is elaborated which involves an optical interference model based on a tri-layer structure and a simple thickness estimation technique. This method was validated on water samples where a good agreement was found with the THz optical parameters of water reported in the literature, while the use of a commercial software resulted in erroneous optical parameters estimates when used without due regard to its limitations. A case study was then performed to demonstrate the ability of the proposed method to characterize agarose hydrogels with varying degree of sulfation. It was demonstrated that THz-TDS can provide insight into the hydration state of the agarose hydrogels, including the relative number of the hydrogen bonds between the hydroxyl moieties of water and the polysaccharide network which is perturbed by the presence of sulfate. The trend in the index of refraction profiles suggested microstructural differences between the agarose hydrogels, which were confirmed by visualizing the agarose network morphology using cryo-SEM imaging.

7.
Food Chem ; 452: 139391, 2024 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-38713980

RESUMEN

Edible insects with high fat and phosphorus content are a potential novel source of lecithin, however, studies on their minor lipids are limited. In this study, lecithin was extracted from black soldier fly larvae and yellow mealworm. Herein, the effects of lecithin extraction method, matrix and ultrasound pretreatment were explored based on the fatty acid composition and phospholipid profile with soy lecithin as a reference. The use of a wet matrix and ultrasound pretreatment increased the extraction efficiency of total PLs from both insects. Insect lecithin contained a considerable amount of sphingomyelin compared to soy lecithin. In insect lecithin, a total of 47 glycerophospholipid and sphingomyelin molecular species, as well as four molecular species of fatty acyl esters of hydroxy fatty acid, were detected. This study is the first comprehensive investigation of insects as a new source of lecithin with applications in food, cosmetics and in the pharmaceutical industry.


Asunto(s)
Larva , Lecitinas , Animales , Lecitinas/química , Larva/química , Larva/crecimiento & desarrollo , Insectos Comestibles/química , Dípteros/química , Dípteros/crecimiento & desarrollo , Tenebrio/química , Simuliidae/química , Ácidos Grasos/química , Ácidos Grasos/aislamiento & purificación , Fosfolípidos/química , Fosfolípidos/aislamiento & purificación , Lípidos/química , Lípidos/aislamiento & purificación
8.
Foods ; 13(9)2024 Apr 29.
Artículo en Inglés | MEDLINE | ID: mdl-38731744

RESUMEN

Palm oil (PO), a semi-solid fat at room temperature, is a popular food ingredient. To steer the fat functionality, sucrose esters (SEs) are often used as food additives. Many SEs exist, varying in their hydrophilic-to-lipophilic balance (HLB), making them suitable for various food and non-food applications. In this study, a stearic-palmitic sucrose ester with a moderate HLB (6) was studied. It was found that the SE exhibited a complex thermal behavior consistent with smectic liquid crystals (type A). Small-angle X-ray scattering revealed that the mono- and poly-esters of the SE have different packings, more specifically, double and single chain-length packing. The polymorphism encountered upon crystallization was repeatable during successive heating and cooling cycles. After studying the pure SE, it was added to palm oil, and the crystallization behavior of the mixture was compared to that of pure palm oil. The crystallization conditions were varied by applying cooling at 20 °C/min (fast) and 1 °C/min (slow) to 0 °C, 20 °C or 25 °C. The samples were followed for one hour of isothermal time. Differential scanning calorimetry (DSC) showed that nucleation and polymorphic transitions were accelerated. Wide-angle X-ray scattering (WAXS) unraveled that the α-to-ß' polymorphic transition remained present upon the addition of the SE. SAXS showed that the addition of the SE at 0.5 wt% did not significantly change the double chain-length packing of palm oil, but it decreased the domain size when cooling in a fast manner. Ultra-small-angle X-ray scattering (USAXS) revealed that the addition of the SE created smaller crystal nanoplatelets (CNPs). The microstructure of the fat crystal network was visualized by means of polarized light microscopy (PLM) and cryo-scanning electron microscopy (cryo-SEM). The addition of the SE created a finer and space-filling network without the visibility of separate floc structures.

9.
Foods ; 12(4)2023 Feb 19.
Artículo en Inglés | MEDLINE | ID: mdl-36832962

RESUMEN

Roasting cocoa beans by means of microwave radiations seems to be a potential alternative to convection roasting, but little is known about the impact of this method on the perceived flavor profile of the chocolate. Therefore, this research focused on revealing the flavor perception of chocolate produced with microwave roasted cocoa beans assessed by both a trained panel and chocolate consumers. Samples of 70% dark chocolate produced from cocoa beans microwave roasted at 600 W for 35 min were compared with samples of 70% dark chocolate produced from cocoa beans convectively roasted at 130 °C for 30 min. Non-significant differences (p > 0.05) in the measured physical properties, such as color, hardness, melting, and flow behavior, showed that chocolate produced from microwave roasted cocoa beans can exhibit the same physical qualities as convection roasted chocolate. Moreover, combined discriminative triangle tests, with 27 judgements in total, performed by a trained panel, showed that each type of chocolate exhibited distinctive characteristics (d'-value = 1.62). Regarding the perceived flavor, "cocoa aroma" was cited as significantly higher for the chocolate produced from microwave roasted cocoa beans (n = 112) compared to chocolate produced from convection roasted cocoa beans (n = 100) by consumers. Both preference and willingness to buy were higher, though insignificant at a 5% level, for the microwave roasted chocolate. A final potential benefit (studied in this research) of microwave roasting cocoa beans is the reduced energy consumption, which was estimated at 75%. Taking all these results together, the microwave roasting of cocoa is shown to be a promising alternative to convection roasting.

10.
Foods ; 12(1)2022 Dec 20.
Artículo en Inglés | MEDLINE | ID: mdl-36613219

RESUMEN

Determining cocoa bean quality is crucial for many players in the international supply chain. However, actual methods rely on a cut test protocol, which is limited by its subjective nature, or on time-consuming, expensive and destructive wet-chemistry laboratory procedures. In this context, the application of near infrared (NIR) spectroscopy, particularly with the recent developments of portable NIR spectrometers, may represent a valuable solution for providing a cocoa beans' quality profile, in a rapid, non-destructive, and reliable way. Monitored parameters in this work were dry matter (DM), ash, shell, fat, protein, total polyphenols, fermentation index (FI), titratable acidity (TA) and pH. Different chemometric analyses were performed on the spectral data and calibration models were developed using modified partial least squares regression. Prediction equations were validated using a fivefold cross-validation and a comparison between the different prediction performances for the portable and benchtop NIR spectrometers was provided. The NIRS benchtop instrument provided better performance of quantification considering the whole than the portable device, showing excellent prediction capability in protein and DM quantification. On the other hand, the NIRS portable device, although showing lower but valuable performance of prediction, can represent an appealing alternative to benchtop instruments for food business operators, being applicable in the field.

11.
Int J Biol Macromol ; 186: 174-180, 2021 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-34252461

RESUMEN

The influence of phenolic compounds on the enzymatic hydrolysis of cellulose was studied in depth using spectrophotometric techniques, adsorption analysis and Scanning Electron Microscopy (SEM). In this paper for the first time, both possible interactions between phenolic compounds and the enzyme or the substrate were investigated, with the use of various phenolic compounds, cellulase from T. reesei, and Avicel as cellulose source. Three classes of phenolic compounds have been identified, based on their effect on the hydrolysis of cellulose: inhibitors (quercetin, kaempferol, trans-cinnamic acid, luteolin, ellagic acid), non-inhibitors (p-coumaric acid, rutin, caffeic acid), and activators (ferulic acid, syringic acid, sinapic acid, vanillic acid). Secondly, since various structures of phenolic compounds were tested, a structure - action comprehensive correlation was possible leading to the conclusion that an -OCH3 group was necessary for the activating effect. Finally, based on the adsorption spectra and unique SEM images, a different way of adsorption (either on the enzyme or on the substrate) was noticed, depending on the activating or inhibiting action of the phenolic compound.


Asunto(s)
Celulasa/antagonistas & inhibidores , Celulosa/metabolismo , Activadores de Enzimas/farmacología , Inhibidores Enzimáticos/farmacología , Fenoles/farmacología , Celulasa/metabolismo , Celulosa/química , Activación Enzimática , Activadores de Enzimas/química , Inhibidores Enzimáticos/química , Hidrólisis , Hypocreales/enzimología , Microscopía Electrónica de Rastreo , Estructura Molecular , Fenoles/química , Espectrofotometría , Relación Estructura-Actividad
12.
J Agric Food Chem ; 69(22): 6281-6290, 2021 Jun 09.
Artículo en Inglés | MEDLINE | ID: mdl-34047549

RESUMEN

Encapsulation is a common approach to improve the bacterial survival of probiotics. In this study, two new low-methoxyl pectins (CMP-6 and CMP-8) were used as coating materials to produce microcapsules (MCs) for the encapsulation of Lactobacillus acidophilus LMG9433T, Lactobacillus casei LMG6904T, and Lactobacillus rhamnosus LMG25859. A fermentation test showed that encapsulation did not influence the fermentation ability of lactobacilli. The biofilm formation of encapsulated lactobacilli was stimulated when an in situ cultivation was conducted on MCs, which was verified by cryo-SEM observation. The resultant biofilm-forming MCs (BMCs) contained high-density bacterial cells (∼1010 CFU/mL). Compared to planktonic lactobacilli, pectin-based MCs showed significant protection for encapsulated lactobacilli from heat shock and simulated gastric digestion. Especially, benefiting from the biofilm formation, BMCs provided higher protection with enhanced resistance to heat shock, freeze-drying, and gastrointestinal digestion than MCs. Our result highlighted the superior bacterial resistances of biofilm-forming probiotics encapsulated in pectinate microcapsules.


Asunto(s)
Pectinas , Probióticos , Biopelículas , Cápsulas , Digestión , Respuesta al Choque Térmico
13.
Food Chem ; 332: 127467, 2020 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-32663755

RESUMEN

The mood pyramid of cocoa, which was previously proposed as a new concept, consists of four levels (flavan-3-ols, methylxanthines, minor compounds and orosensory properties). Roasting is a crucial process for flavor development in cocoa but is likely to have a negative impact on the phytochemicals. We investigated the effect of roasting time (10-50 min) and temperature (110-160 °C) on the potential mood-enhancing compounds corresponding to the distinct mood pyramid levels. Phytochemicals were analyzed using UPLC-HRMS, while the flavor was mapped via aroma (HS-SPME-GC-MS) and generic descriptive analysis (trained panel). Results revealed that roasting at 130 °C for 30 min did not significantly affect the levels of epicatechin, procyanidin B2 and theobromine, while salsolinol significantly increased. Moreover, bitterness and astringency were reduced and the desired cocoa flavor was developed. Thus, through selection of appropriate roasting time and temperature conditions phytochemicals of interest could be retained without comprising the flavor.


Asunto(s)
Cacao/química , Culinaria/métodos , Semillas/química , Biflavonoides/química , Catequina/química , Aromatizantes/química , Cromatografía de Gases y Espectrometría de Masas , Calor , Humanos , Odorantes/análisis , Polifenoles/química , Proantocianidinas/química , Gusto
14.
Food Res Int ; 132: 109116, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32331645

RESUMEN

The impact of pod storage (PS) and roasting temperature (RT) on the quality parameters and the sensory profiles of dark chocolates were evaluated. Dark chocolates (70%) from ten liquors of different PS and RT combinations as well as six liquors of different origins (Ecuador, Ghana, Ivory Coast, Madagascar, Venezuela and Vietnam) with variable genetic groups were produced under identical conditions and compared. To a greater extent, the range of chocolate quality attributes underscored the generally minimal effects of PS, RT and origin of liquor on the processing conditions. Although with a few exceptions, generally, chocolate acidity (pH and TA) decreased with increasing PS and vice versa in the case of RT. Furthermore, results from a balanced incomplete block design (BIBD) involving a 16-member expert panel also revealed the impact of the applied treatments (PS and RT) on the final flavor profiles of the chocolates irrespective of the origin or genetic groups of the cocoa beans. The same was confirmed when instrumental aroma results were correlated with the sensory data using partial least squares (PLS) regression models. Thus, this study demonstrates the possibility of creating diverse flavor profiles (even towards 'fine' flavor) from 'bulk' cocoa beans through an optimized combination of PS and RT. The findings are therefore expected to challenge the status-quo, especially in the way 'bulk' cocoa is currently processed and consequently priced, thereby, possibly fostering a win-win situation between cocoa producers and industries.


Asunto(s)
Cacao/química , Chocolate/análisis , Aromatizantes , Adulto , Bebidas Alcohólicas/análisis , Ecuador , Femenino , Ghana , Dureza , Humanos , Madagascar , Masculino , Odorantes/análisis , Gusto , Temperatura de Transición , Compuestos Orgánicos Volátiles/análisis
15.
Chem Phys Lipids ; 230: 104912, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32371001

RESUMEN

Phytosterols (PSs) are insoluble in water and poorly soluble in oil, which hampers their potential as cholesterol level regulator in human. To mitigate this problem, monoglycerides (MGs) were used to modulates the crystallization behavior of PSs. Therefore, the understanding on mixing behavior provides the insight into different aspects of crystallization and the resultant effects. The effects on thermal, morphology, diffraction, and spectroscopy behavior were investigated for binary mixtures of 11 different ratios (100:0 to 0:100 MGs:PSs). The phase behavior of binary mixtures of commercial MGs and PSs exhibited complexity with the formation of eutectic mixtures at 90:10 and 80:20 (MGs:PSs) combinations. These combinations revealed a single melting profile and reduced melting enthalpy, though after a month of storage at 5 °C. Conversely, two separate melting regions were observed in others. Furthermore, powder X-ray diffraction (PXRD) analysis of selected combinations revealed a change in crystalline forms with changes in the peaks located between 18-19° (2θ) and 25-26° (2θ). Accordingly, Raman spectroscopy results revealed changes in intensities and peak shape. Therefore, the change in crystalline forms or behavior correlated well to the change in thermal properties. Overall, the characterizations revealed the formation of eutectic mixtures between MGs and PSs at 90:10 and 80:20 (MGs:PSs) in which MGs modified the crystallization of PSs and changed the crystal forms thus, thermal behaviors. This study provides new insight into the mixing behavior of MGs and PSs which supports other research. Therefore, the results of this study are beneficial for the improvement of formulation of phytosterols in food and pharmaceutical products. Nonetheless, this study reveals a simple technique to alter crystal forms of phytosterols through simple complexation with monoglycerides.


Asunto(s)
Monoglicéridos/química , Fitosteroles/química , Cristalografía por Rayos X , Modelos Moleculares , Conformación Molecular , Solventes/química
16.
Food Chem ; 305: 125436, 2020 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-31514047

RESUMEN

The physicochemical properties of wheat bran have an effect on its technofunctional and nutritional profile. The possibility to induce physicochemical modifications in wheat bran using microfluidisation was investigated. An I-optimal experimental design was used to investigate the effect of microfluidisation processing parameters (pressure, number of passes, bran concentration and initial particle size) on important properties of wheat bran (particle size, microstructure, chemical composition, water retention capacity (WRC), extractability, viscosity and sedimentation). With the parameters used in this study, microfluidisation reduced wheat bran median particle size to 14.8 µm and disintegrated starch granules from the attached endosperm. This coincided with an increased extractability of starch and arabinoxylan. While the initial particle size was of minor importance, a higher pressure, larger number of passes and lower bran concentration during microfluidisation resulted in a smaller particle size, higher WRC and extractability, and an increased viscosity and stability in a 2% wheat bran suspension.


Asunto(s)
Fibras de la Dieta/análisis , Triticum/química , Endospermo/química , Tamaño de la Partícula , Almidón , Viscosidad , Agua , Xilanos
17.
Appetite ; 53(1): 16-23, 2009 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-19447521

RESUMEN

Bread contains a wide range of important nutritional components which provide a positive effect on human health. However, the consumption of bread is declining during the last decades. This is due to factors such as changing eating patterns and an increasing choice of substitutes like breakfast cereals and fast foods. The aim of this study is to investigate consumer's quality perception of bread towards sensory, health and nutrition attributes. Four consumer segments are identified based on these attributes. The different consumer segments comprise consumers being positive to all three quality aspects of bread ("enthusiastic") as wells as consumers perceiving bread strongly as "tasteless", "non-nutritious" or "unhealthy". Moreover, factors are identified which influence the consumers' quality perception of bread. The results of our study may help health professionals and policy makers to systematically inform consumers about the positive effects of bread based on its components. Furthermore, firms can use the results to build up tailor-made marketing strategies.


Asunto(s)
Pan , Comportamiento del Consumidor , Percepción , Adulto , Anciano , Conducta , Composición Familiar , Femenino , Grupos Focales , Etiquetado de Alimentos , Promoción de la Salud , Humanos , Masculino , Persona de Mediana Edad , Valor Nutritivo , Sensación , Encuestas y Cuestionarios , Gusto
18.
Food Res Int ; 122: 411-418, 2019 08.
Artículo en Inglés | MEDLINE | ID: mdl-31229095

RESUMEN

Since insects are a promising alternative protein source, the application potential of three insect larvae (Alphitobius diaperinus, Tenebrio molitor and Zophobas morio) for food purposes was explored. To this end, the effect of isothermal heating at 5 different temperatures (70 °C-90 °C) on structure formation in insect batters was studied rheologically. Meat batters (with the same protein content as insect batters), isothermally heated at 70 °C, were also studied for comparison. Cryo-SEM imaging was used to visualize the microstructure of raw and heated insect batters. These images showed that a network was formed in the heated batters, as well as in the raw batters. However, no clear effect of temperature or insect larva on the microstructure was observed. Rheologically, both the heating temperature applied and the insect larva used were shown to have a significant effect on the viscoelastic properties of the insect batters. Generally, batters containing Z. morio larvae showed both higher storage moduli (G') and longer linear viscoelastic regions (LVRs) compared to the other insect larvae, indicating that these larvae had the best structure forming capacities. Furthermore, both G' and the length of the LVR increased with increasing isothermal heating temperature, indicating more structure formation and structure stability in insect batters heated at higher temperatures. Compared to the meat batters, however, the insect larvae were shown to have inferior structure forming capacities. Even at the highest heating temperature (90 °C) the viscoelastic properties of the insect batters only approached those of meat batters heated at 70 °C. Therefore, it was concluded that higher heating temperatures may need to be employed in insect-based food products compared to meat products in order to obtain sufficient structure formation and the desired textural properties.


Asunto(s)
Calor , Insectos/metabolismo , Animales , Escarabajos/metabolismo , Proteínas en la Dieta/metabolismo , Proteínas de Insectos/metabolismo , Larva/metabolismo , Reología , Tenebrio/metabolismo
19.
Food Res Int ; 120: 819-828, 2019 06.
Artículo en Inglés | MEDLINE | ID: mdl-31000302

RESUMEN

The presence of a fat crystal network throughout the fat droplets of an oil-in-water emulsion is a requisite for partial coalescence. The characteristics of this fat crystal network determine greatly the kinetics of partial coalescence. In this study the fat crystal network was manipulated by altering the cooling rate applied to natural cream. The kinetics of partial coalescence under constant shear and at constant temperature were studied by combining rotational viscosity analysis with light microscopy and laser scattering. It was shown that slow cooling of the emulsion decelerates partial coalescence and favors the formation of loosely-packed aggregates. On the other hand, fast cooling favors a high partial coalescence rate and the formation of dense aggregates. Fat crystallization properties were analyzed using small deformation rheology, differential scanning calorimetry and cryo-scanning electron microscopy. The difference in organization of the fat crystals obtained for both cooling rates contributed significantly to the mechanistic understanding of partial coalescence as influenced by the cooling rate.


Asunto(s)
Frío , Productos Lácteos/análisis , Manipulación de Alimentos/métodos , Emulsiones , Transición de Fase
20.
Food Res Int ; 125: 108550, 2019 11.
Artículo en Inglés | MEDLINE | ID: mdl-31554139

RESUMEN

The unique impact of roasting conditions on the aroma quality of cocoa beans has been demonstrated in many studies. However, information on the additional impact of pod storage (PS) and its combined effect with roasting temperature (RT) is unknown. Hence, this study sought to elucidate the collective contribution of these post-harvest/process parameters on the aroma profiles of cocoa liquors produced from Forastero cocoa beans. The beans had been subjected to different treatments following a 3 × 4 full factorial experiment, consisting of PS (0, 3, 7 days) and RT (100, 120, 140, 160 °C). Statistical analysis of the results from HS-SPME-GC-MS revealed significant (p < .05) impact of both PS and RT as well as their interaction effects on the ten groups of volatiles (acids, alcohols, esters, terpenes, aldehydes, ketones, pyrazines, furans, pyrroles and others) and their overall aroma concentration. An exception was however noted for aldehydes, where the total concentration was only significantly (p < .05) influenced by the individual effects of PS and RT. A subsequent clustering of the liquors, first on the basis of all identified volatiles, then, on the basis of the odor-active volatiles, also revealed similar pattern where liquors with high RT's possessed more volatiles with higher concentrations and vice versa. More so, it seemed that no or very minimal PS treatment was necessary for preserving more aromatic volatiles with typically fruity, floral or spicy flavor notes, whereas, for liquors with volatiles exhibiting more cocoa, chocolate, nutty and roasted flavor notes, prolonged PS (> 3 days) treatment was required. These findings are expected to challenge the status-quo, specifically in the conventional ways through which the aroma potential of 'bulk' cocoa may be steered. On the one hand, the idea of manipulating PS treatment and roasting conditions may indeed consolidate the possibility of creating diverse and/or distinct aroma profiles from the same 'bulk' cocoa beans, whereas, on the other hand, it raises the question whether the Ghanaian cocoa beans - being described as 'bulk' cocoa - could be a consequence of prolonged pod storage treatment.


Asunto(s)
Bebidas Alcohólicas/análisis , Cacao/química , Culinaria/métodos , Odorantes/análisis , Semillas/química , Almacenamiento de Alimentos/métodos , Calor , Compuestos Orgánicos Volátiles/análisis
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