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1.
J Dairy Res ; 91(1): 10-18, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38361413

RESUMO

This research paper addresses the hypothesis that there is an optimal amount of intestinally available oleic acid (provided via abomasal infusion) to produce higher-oleic acid milk fat with satisfactory functional characteristics of cream and butter oil. A control and four increasing doses of free fatty acids from high oleic sunflower oil (HOSFA) were infused into the abomasum of four lactating dairy cows in a crossover experimental design with 7-d periods. Treatments were: (1) control (no HOSFA infused), (2) HOSFA (250 g/d), (3) HOSFA (500 g/d), (4) HOSFA (750 g/d), and (5) HOSFA (1000 g/d). All treatments included meat solubles and Tween 80 as emulsifiers. Viscosity, overrun and whipping time as well as foam firmness and stability were evaluated in whipping creams (33% fat). Solid fat content (from 0 to 40°C), melting point and firmness were determined in butter oil. Whipping time of cream increased linearly and viscosity decreased linearly as infusion of HOSFA increased. Overrun displayed a quadratic response, decreasing when 500 g/d or more was infused. Foam firmness and stability were not affected significantly by HOSFA. For butter oil, melting point, firmness, and solid fat content decreased as HOSFA infusion increased. Changes in 21 TG fractions were statistically correlated to functional properties, with 6-10 fractions showing the highest correlations consistently. Decisions on the optimal amount of HOSFA were dependent on the dairy product to which milk fat is applied. For products handled at commercial refrigeration temperatures, such as whipping cream and butter oil, the 250 g/d level was the limit to maintain satisfactory functional qualities. Palmitic acid needed to be present in at least 20% in milk fat to keep the functional properties for the products.


Assuntos
Abomaso , Leite , Ácido Oleico , Óleos de Plantas , Óleo de Girassol , Animais , Bovinos , Feminino , Leite/química , Viscosidade , Óleo de Girassol/química , Abomaso/efeitos dos fármacos , Óleos de Plantas/administração & dosagem , Estudos Cross-Over , Lactação/efeitos dos fármacos , Manipulação de Alimentos/métodos
2.
J Food Sci ; 86(6): 2655-2670, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34018184

RESUMO

The use of high-solid gels (HSGs) in the confectionary and dietary supplement industries is rapidly expanding, increasing the interest in studying the relationships across their composition, sensory characteristics, thermal behavior, and texture. Thus, the objectives of this study were to characterize HSG product categories based on sensory characteristics and analytical parameters, and correlate analytical parameters with sensory descriptors generated through napping-ultra flash profile (napping-UFP). In one 90-min session, 15 panelists performed two napping-UFP exercises, categorizing and describing 13 confectionary HSGs by their overall degree of similarity and by their texture. Multiple factor analysis and hierarchical clustering were conducted on the napping-UFP data. The products were also characterized by their moisture content, water activity (aw ), thermal behavior, and texture profile. Principal component analysis and hierarchical clustering analysis were conducted on the analytical parameters; additionally, the analytical parameters were related to the sensory descriptors using Spearman's correlation. The panelists predominantly focused on texture to categorize the samples. The clustering of the samples across the napping-UFP exercises resulted in two categories-gelatin and nongelatin-containing products. Sensory descriptors generated by panelists during the napping-UFP were significantly correlated to the measured analytical parameters. The difference in texture between the two clusters, associated with the presence of a small (3 J/g) gelatin triple-helix structure as determined by differential scanning calorimetry (DSC), was significant enough to be perceived by panelists. These findings indicate that modified starch and pectin, impart different sensory characteristics than gelatin and have important implications for developing new formulations for HSGs in which gelatin-like texture is desirable. PRACTICAL APPLICATION: Increased consumer demands for nonanimal-derived ingredients have fueled the food and pharmaceutical industries interest in both finding an economical replacement material for gelatin and gaining a deeper understanding of gelatin's textural and thermal properties. The results of this research have important implications for finding suitable ingredients to replace gelatin in high-solid confectionary gels, as well as enhancing the quality of current gelatin-containing HSGs. The triple-helix is a powerful structural element that determined the textural properties perceived by panelists in HSGs. Consequently, the search for a replacement material for gelatin should focus on identifying materials that impart similar properties as the triple-helix structure, helping to create products with gelatin-like texture. Additionally, these findings begin to provide a better understanding of the thermal behavior of gelatin for enhancing the functionality, stability, and product integrity of HSG systems throughout shipping, storage, and consumption. Additional research is underway to explore in detail the thermal behavior of gelatin in commercial and model gummy systems.


Assuntos
Suplementos Nutricionais , Gelatina/química , Géis/química , Géis/classificação , Amido/química , Varredura Diferencial de Calorimetria , Análise por Conglomerados , Humanos
3.
J Food Sci Educ ; 19(3): 110-115, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32837345
4.
J Food Sci Educ ; 19(2): 28-29, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32508543
5.
J Food Sci ; 82(9): 2167-2176, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28796325

RESUMO

Stickiness is an important texture attribute in many food systems, but its meaning can vary by person, product, and throughout mastication. This variability and complexity makes it difficult to devise analytical tests that accurately and consistently predict sensory stickiness. Glass transition temperature (Tg ) is a promising candidate for texture prediction. Our objective is to elucidate the temporal profile of stickiness in order to probe the relationship between Tg and dynamic stickiness perception. Nine caramel samples with diverse texture and thermal profiles were produced for sensory testing and differential scanning calorimetry. Sixteen trained panelists generated stickiness-relevant terms to be used in a subsequent temporal dominance of sensation (TDS) test with the same panelists. Following the TDS study, these panelists also rated samples for overall tactile and oral stickiness. Stickiness ratings were then correlated to TDS dominance parameters across the full evaluation period and within the first, middle, and final thirds of the evaluation period. Samples with temporal texture profiles dominated by tacky, stringy, and enveloping attributes consistently received the highest stickiness scores, although the correlation strength varied by time period. Tg was found to correlate well with trained panelist and consumer ratings of oral (R2trained = 0.85; R2consumer = 0.96) and tactile (R2trained = 0.78; R2consumer = 0.79) stickiness intensity, and stickiness intensity ratings decreased with Tg of completely amorphous samples. Further, glassy samples followed a different texture trajectory (brittle-cohesive-toothpacking) than rubbery samples (deformable-tacky-enveloping). These results illuminate the dynamic perception of stickiness and support the potential of Tg to predict both stickiness intensity and texture trajectory in caramel systems.


Assuntos
Doces/análise , Varredura Diferencial de Calorimetria , Carboidratos , Humanos , Mastigação , Percepção , Paladar , Temperatura de Transição , Viscosidade
6.
J Food Sci ; 82(8): 1935-1946, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28675759

RESUMO

Sugar reduction in processed foods is a pressing and complex problem, as sugars contribute important sensory and physical properties to foods. Composed of sugars and lipids, caramel coating systems, like the coating in caramel popcorns, exemplify this challenge. In order to probe the feasibility and consequences of sugar reduction, both sensory and physical properties were measured for 3 types of caramel coating systems. Four commonly used sugar alcohols, isomalt, maltitol, mannitol, and sorbitol, with different thermal properties and relative sweetness values were chosen to replace sugar in the caramel coating systems at 25% and 50% sugar reduction levels. Full sugar (control) and reduced sugar caramel coating samples were prepared in duplicate. Ten trained panelists participated in a 6-wk descriptive analysis panel to define and quantify the intensity of important sensory characteristics. All 24 sensory terms generated by the panel differed significantly across caramel type and sugar replacer. Thermal properties were measured through differential scanning calorimetry, and textural properties were measured through texture profile analysis. Replacement of sugar with sugar alcohols was found to decrease the glass transition temperature and systematically alter the hardness and resilience of caramel samples. Principal component analysis of sensory and physical data revealed that caramel coating type dictates caramel aroma, aroma by mouth, taste, and aftertaste, while sugar replacer and replacement level dictate texture. This research represents the first comprehensive study of the effects of sugar reduction in a caramel coating system and suggests successful strategies for sugar reduction and key parameters to control in reduced sugar systems.


Assuntos
Doces/análise , Açúcares/química , Paladar , Carboidratos , Dissacarídeos/análise , Dureza , Humanos , Maltose/análogos & derivados , Maltose/análise , Odorantes/análise , Álcoois Açúcares/análise
7.
J Food Sci ; 79(11): S2362-7, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25308071

RESUMO

Beet sugar contains an off-aroma, which was hypothesized to generate expectations on the acceptability of a product made with beet sugar. Thus, the objective of this study was to assess the impact of information about the sugar source (beet vs. cane) on the overall liking of an orange-flavored beverage. One hundred panelists evaluated an orange-flavored powdered beverage mix and beverage made with beet and cane sugars using a 5-phase testing protocol involving a tetrad test and hedonic ratings performed under blind and informed conditions. Tetrad test results indicated that there was a significant difference (P < 0.05) between the beverage mix made with beet sugar and cane sugar; however, no difference was found between the beverage made with beet sugar and cane sugar. Hedonic ratings revealed the significance of information conditions on the panelists evaluation of sugar (F = 24.67, P < 0.001); however, no difference in the liking was identified for the beverage mix or beverage. Average hedonic scores were higher under informed condition compared to blind condition for all products, possibly because labels tend to reduce uncertainty about a product. Results from this study are representative of the responses from the general population and suggest that they are not affected by sugar source information in a beverage product. Based on concerns with the use of beet sugar expressed in the popular press, there may be a subgroup of the population that has a preconceived bias about sugar sources due to their prior experiences and knowledge and, thus, would be influenced by labels indicating the sugar source used in a product.


Assuntos
Beta vulgaris/química , Bebidas/análise , Sacarose Alimentar/análise , Preferências Alimentares , Saccharum/química , Adolescente , Adulto , Feminino , Rotulagem de Alimentos , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
8.
J Food Sci ; 79(11): S2354-61, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25308166

RESUMO

Although beet and cane sugar sources have nearly identical chemical compositions, the sugars differ in their volatile profiles, thermal behaviors, and minor chemical components. Scientific evidence characterizing the impact of these differences on product quality is lacking. The objective of this research was to determine whether panelists could identify a sensory difference between product matrices made with beet and cane sugar sources. Sixty-two panelists used the R-index by ranking method to discern whether there was a difference between 2 brands of beet and 2 brands of cane sugars in regard to their aroma and flavor, along with a difference in pavlova, simple syrup, sugar cookies, pudding, whipped cream, and iced tea made with beet and cane sugars. R-index values and Friedman's rank sum tests showed differences (P < 0.05) between beet and cane sugars in regard to their aroma and flavor. Significant differences between the sugar sources were also identified when incorporated into the pavlova and simple syrup. No difference was observed in the sugar cookies, pudding, whipped cream, and iced tea. Possible explanations for the lack of difference in these products include: (1) masking of beet and cane sensory differences by the flavor and complexity of the product matrix, (2) the relatively small quantity of sugar in these products, and (3) variation within these products being more influential than the sugar source. The findings from this research are relevant to sugar manufacturers and the food industry as a whole, because it identifies differences between beet and cane sugars and product matrices in which beet and cane sugars are not directly interchangeable.


Assuntos
Beta vulgaris/química , Sacarose Alimentar/análise , Saccharum/química , Paladar , Adolescente , Adulto , Feminino , Manipulação de Alimentos , Humanos , Masculino , Odorantes/análise , Olfato , Adulto Jovem
9.
J Food Sci ; 79(11): E2232-44, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25308254

RESUMO

Water-solid interactions are known to play a major role in the chemical and physical stability of food materials. Despite its extensive use throughout the food industry, the mechanism and parameters of hydrate formation and loss in glucose are not well characterized. Hydrate formation in alpha-anhydrous glucose (α-AG) and hydrate loss in glucose monohydrate (GM) were studied under equilibrium conditions at various relative humidity (RH) values using saturated salt slurries for 1 y. The mechanism of hydrate formation and hydrate loss were determined through mathematical modeling of Dynamic Vapor Sorption data and Raman spectroscopy was used to confirm the mechanisms. The critical temperature for hydrate loss in GM was determined using thermogravimetric analysis (TGA). The moisture sorption profiles of α-AG and GM were also studied under dynamic conditions using an AquaSorp Isotherm Generator. Hydrate formation was observed at and above 68% RH at 25 °C and the conversion of α-AG to GM can best be described as following a nucleation mechanism, however, diffusion and/or geometric contraction mechanisms were also observed by Raman spectroscopy subsequent to the coalescence of initial nucleation sites. Hydrate loss was observed to occur at and below 11% RH at 25 °C during RH storage and at 70 °C during TGA. The conversion of GM to α-AG follows nucleation and diffusion mechanisms. Hydrate formation was evident under dynamic conditions in α-AG and GM prior to deliquescence. This research is the first to report hydrate formation and loss parameters for crystalline α-AG and GM during extended storage at 25 ˚C.


Assuntos
Glucose/química , Água/química , Cristalização , Análise Espectral Raman , Temperatura , Termogravimetria
10.
J Food Sci ; 79(9): S1763-8, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25124655

RESUMO

Research concerning the sensory properties of beet and cane sugars is lacking in the scientific literature. Therefore, the objectives of this research were to determine whether a sensory difference was perceivable between beet and cane sugar sources in regard to their (1) aroma-only, (2) aroma and taste without nose clips, and (3) taste-only with nose clips, and to characterize the difference between the sugar sources using descriptive analysis. One hundred panelists evaluated sugar samples using a tetrad test. A significant difference (P < 0.05) was identified between beet and cane sugar sources when evaluated by aroma-only and taste and aroma without nose clips. However, there was no difference when tasted with nose clips. To characterize the observed differences, ten trained panelists identified and quantified key sensory attributes of beet and cane sugars using descriptive analysis. Analysis of variance indicated significant differences (P < 0.05) between sugar samples for 8 of the 10 attributes including: off-dairy, oxidized, earthy, and barnyard aroma, fruity and burnt sugar aroma-by-mouth, sweet aftertaste, and burnt sugar aftertaste. The sensory profile of beet sugar was characterized by off-dairy, oxidized, earthy, and barnyard aromas and by a burnt sugar aroma-by-mouth and aftertaste, whereas cane sugar was characterized by a fruity aroma-by-mouth and sweet aftertaste. This study shows that beet and cane sugar sources can be differentiated by their aroma and provides a sensory profile characterizing the differences. As sugar is used extensively as a food ingredient, sensory differences between beet and cane sugar sources once incorporated into different product matrices should be studied as a next step.


Assuntos
Beta vulgaris/química , Saccharum/química , Adolescente , Adulto , Comportamento do Consumidor , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Odorantes , Olfato , Paladar , Adulto Jovem
12.
J Agric Food Chem ; 61(38): 9241-50, 2013 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-23977884

RESUMO

Deliquescence is a first-order phase transformation of a crystalline solid to a saturated solution that is triggered at a defined relative humidity (RH), RH0. Previous studies demonstrated that the RH0 of an inorganic substance with a positive heat of solution (ΔH) will decrease with increases in temperature. In this study, the relationships between ΔH, solubility, and deliquescence RH for single-ingredient and multicomponent systems were investigated. The deliquescence RHs of inorganic and organic crystalline solids and their mixtures were measured at temperatures ranging from 20 to 40 °C using a water activity meter and various gravimetric moisture sorption analyzers. The deliquescence behavior as a function of temperature for organic food ingredients was thermodynamically modeled and followed similar trends to those of the previously investigated inorganic ingredients. Furthermore, the models can be used as a predictive approach to determine physical stability and deliquescence RHs of deliquescent ingredients and blends if the storage temperature and ingredient ΔH and solubility are known.


Assuntos
Análise de Alimentos , Manipulação de Alimentos , Umidade , Pós/química , Solubilidade , Temperatura , Termodinâmica , Água
13.
J Food Sci ; 76(1): E149-57, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21535666

RESUMO

Recent research has demonstrated that the critical relative humidity (RHc) values, obtained using automatic water vapor sorption instruments, can be used to detect the glassy to rubbery transition. However, reported time dependency of these RHc values suggests that additional research be carried out using equilibrium water vapor sorption methods. Thus, the objectives of this study were to: (1) determine the RHc for amorphous polydextrose at various temperatures using both instrumental (Dynamic Vapor Sorption [DVS] ramping and equilibrium) and saturated salt slurry methods, and (2) compare the RHc values obtained via sorption methods to the glass transition temperature (Tg) values obtained via differential scanning calorimetry (DSC). When plotted as a "glass curve" on a state diagram, the RHc values (plotted as a function of temperature) were found to be similar to the Tg values (plotted as a function of relative humidity). Of the 3 sorption methods employed, at 25 °C, the saturated salt slurry exhibited the lowest RHc value (34.3%), followed by the DVS equilibrium method (41.7%), and the DVS ramping method (49.9%). The RHc DVS equilibrium method was closest to the calculated DSC Tg onset RHc value (41.6% at 25 °C). These water sorption methods show promise as practical tools for predicting the quality and stability attributes of amorphous materials by being able to routinely determine the location of the glassy to rubbery transition. Future research applying these sorption methods to more complex amorphous food systems is suggested. Practical Application: Despite its extreme usefulness, the Tg, a key element of the Food Polymer Science approach, remains a challenging parameter to routinely measure in amorphous food materials. Recent research has demonstrated that the RHc values can be used to detect the glassy to rubbery transition. However, reported time dependency of these RHc values suggests that additional research be carried out using equilibrium water vapor sorption methods. Therefore, in this research 2 instrumental (DVS ramping and equilibrium) methods and the traditional saturated salt slurry method were used to obtain RHc values, comparing them to DSC obtained Tg values. The water sorption methods show promise as practical tools for predicting the quality and stability attributes of amorphous materials by being able to routinely determine the location of the glassy to rubbery transition. Future research applying these sorption methods to more complex amorphous food systems is suggested.


Assuntos
Aditivos Alimentares/química , Tecnologia de Alimentos , Glucanos/química , Água/análise , Absorção , Adsorção , Algoritmos , Varredura Diferencial de Calorimetria , Fenômenos Químicos , Modelos Químicos , Transição de Fase , Controle de Qualidade , Vapor , Temperatura , Temperatura de Transição
14.
J Food Sci ; 76(1): E78-89, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21535679

RESUMO

Similar to an increase in temperature at constant moisture content, water vapor sorption by an amorphous glassy material at constant temperature causes the material to transition into the rubbery state. However, comparatively little research has investigated the measurement of the critical relative humidity (RHc) at which the glass transition occurs at constant temperature. Thus, the central objective of this study was to investigate the relationship between the glass transition temperature (Tg), determined using thermal methods, and the RHc obtained using an automatic water vapor sorption instrument. Dynamic dewpoint isotherms were obtained for amorphous polydextrose from 15 to 40 °C. RHc was determined using an optimized 2nd-derivative method; however, 2 simpler RHc determination methods were also tested as a secondary objective. No statistical difference was found between the 3 RHc methods. Differential scanning calorimetry (DSC) Tg values were determined using polydextrose equilibrated from 11.3% to 57.6% RH. Both standard DSC and modulated DSC (MDSC) methods were employed, since some of the polydextrose thermograms exhibited a physical aging peak. Thus, a tertiary objective was to compare Tg values obtained using 3 different methods (DSC first scan, DSC rescan, and MDSC), to determine which method(s) yielded the most accurate Tg values. In general, onset and midpoint DSC first scan and MDSC Tg values were similar, whereas onset and midpoint DSC rescan values were different. State diagrams of RHc and experimental temperature and Tg and %RH were compared. These state diagrams, though obtained via very different methods, showed relatively good agreement, confirming our hypothesis that water vapor sorption isotherms can be used to directly detect the glassy to rubbery transition. Practical Application: The food polymer science (FPS) approach, pioneered by Slade and Levine, is being successfully applied in the food industry for understanding, improving, and developing food processes and products. However, despite its extreme usefulness, the Tg, a key element of the FPS approach, remains a challenging parameter to routinely measure in amorphous food materials, especially complex materials. This research demonstrates that RHc values, obtained at constant temperature using an automatic water vapor sorption instrument, can be used to detect the glassy to rubbery transition and are similar to the Tg values obtained at constant %RH, especially considering the very different approaches of these 2 methods--a transition from surface adsorption to bulk absorption (water vapor sorption) versus a step change in the heat capacity (DSC thermal method).


Assuntos
Fibras na Dieta/análise , Tecnologia de Alimentos , Glucanos/química , Água/análise , Absorção , Adsorção , Varredura Diferencial de Calorimetria/métodos , Fenômenos Químicos , Fibras na Dieta/administração & dosagem , Alimentos Fortificados/análise , Modelos Químicos , Transição de Fase , Reologia , Vapor , Temperatura , Temperatura de Transição
15.
J Agric Food Chem ; 59(7): 3306-10, 2011 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-21417276

RESUMO

The loss of crystalline structure in sucrose, glucose, and fructose has been shown to be due to the kinetic process of thermal decomposition (termed apparent melting), rather than thermodynamic melting. The purpose of this research was to investigate whether or not it is possible to scan quickly enough to suppress the kinetic process of thermal decomposition and reach the thermodynamic melting temperature of these sugars using a new rapid-scanning DSC. Indium, a thermodynamic melting material, and sucrose, glucose, and fructose were analyzed at three heating rates from 1 to 25 °C/min using standard DSC and at seven heating rates from 50 to 2000 °C/min using rapid-scanning DSC. Thermodynamic melting was achieved when the onset temperature (T(m onset)) of the endothermic peak leveled off to a constant value independent of heating rate. The T(m onset) for indium was constant (156.74 ± 0.42 °C) at all heating rates. In the case of fructose, the T(m onset) increased considerably until a heating rate of approximately 698 °C/min, after which the average T(m onset) for the remaining three heating rates was constant at 135.83 ± 1.14 °C. Thus, 135.83 °C is proposed to be the thermodynamic melting temperature of fructose. It is important to note that the heating rate at which this thermodynamic melting temperature is achieved is most likely influenced by the type and amount of trace components (e.g., water and salts) contained in the fructose, which are known to vary widely in sugars. In the case of sucrose and glucose, thermodynamic melting temperatures were not able to be obtained, because the upper limit heating rate used was not fast enough to suppress thermal decomposition and achieve thermodynamic melting, perhaps due to the higher apparent T(m onset) for sucrose and glucose compared to that for fructose.


Assuntos
Varredura Diferencial de Calorimetria , Frutose/química , Glucose/química , Sacarose/química , Cristalização , Termodinâmica , Temperatura de Transição
16.
J Agric Food Chem ; 59(7): 3311-9, 2011 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-21381719

RESUMO

This research investigates the effects of heating conditions used to produce amorphous sucrose on its glass transition (T(g)) parameters, because the loss of crystalline structure in sucrose is caused by the kinetic process of thermal decomposition. Amorphous sucrose samples were prepared by heating at three different scan rates (1, 10, and 25 °C/min) using a standard differential scanning calorimetry (SDSC) method and by holding at three different isothermal temperatures (120, 132, and 138 °C) using a quasi-isothermal modulated DSC (MDSC) method. In general, the quasi-isothermal MDSC method (lower temperatures for longer times) exhibited lower T(g) values, larger ΔC(p) values, and broader glass transition ranges (i.e., T(g end) minus T(g onset)) than the SDSC method (higher temperatures for shorter times), except at a heating rate of 1 °C/min, which exhibited the lowest T(g) values, the highest ΔC(p), and the broadest glass transition range. This research showed that, depending on the heating conditions employed, a different amount and variety of sucrose thermal decomposition components may be formed, giving rise to wide variation in the amorphous sucrose T(g) values. Thus, the variation observed in the literature T(g) values for amorphous sucrose produced by thermal methods is, in part, due to differences in the heating conditions employed.


Assuntos
Temperatura Alta , Sacarose/química , Temperatura de Transição , Varredura Diferencial de Calorimetria , Cristalização , Termodinâmica
17.
J Agric Food Chem ; 59(2): 684-701, 2011 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-21175199

RESUMO

Thermodynamic melting occurs at a single, time-independent temperature with a constant enthalpy value. However, substantial variation in the melting parameters (T(m onset), T(m peak), and ΔH) for sucrose, glucose, and fructose has been reported in the literature. Although a number of explanations have been put forth, they do not completely account for the observed variation. Thus, this research was performed to elucidate the fundamental mechanism underlying the loss of crystalline structure in the sugars using both thermal (Part I) and chemical (Part II) analysis approaches. A strong heating rate dependency observed in the melting parameters for the sugars implies the occurrence of a kinetic process during the loss of crystalline structure. The difference in heat capacity and modulated heat flow amplitude in the stepwise quasi-isothermal modulated differential scanning calorimetry experiments for the sugars compared to indium and mannitol (thermodynamic melting comparison materials) strongly suggests thermal decomposition as the kinetic process responsible for the loss of crystalline structure, which is the critical difference between our conclusion and others. We propose the term "apparent melting" to distinguish the loss of crystalline structure due to a kinetic process, such as thermal decomposition, from thermodynamic melting.


Assuntos
Frutose/química , Glucose/química , Sacarose/química , Temperatura Alta , Cinética , Estrutura Molecular , Termodinâmica
18.
J Agric Food Chem ; 59(2): 702-12, 2011 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-21175200

RESUMO

High performance liquid chromatography (HPLC) on a calcium form cation exchange column with refractive index and photodiode array detection was used to investigate thermal decomposition as the cause of the loss of crystalline structure in sucrose. Crystalline sucrose structure was removed using a standard differential scanning calorimetry (SDSC) method (fast heating method) and a quasi-isothermal modulated differential scanning calorimetry (MDSC) method (slow heating method). In the fast heating method, initial decomposition components, glucose (0.365%) and 5-HMF (0.003%), were found in the sucrose sample coincident with the onset temperature of the first endothermic peak. In the slow heating method, glucose (0.411%) and 5-HMF (0.003%) were found in the sucrose sample coincident with the holding time (50 min) at which the reversing heat capacity began to increase. In both methods, even before the crystalline structure in sucrose was completely removed, unidentified thermal decomposition components were formed. These results prove not only that the loss of crystalline structure in sucrose is caused by thermal decomposition, but also that it is achieved via a time-temperature combination process. This knowledge is important for quality assurance purposes and for developing new sugar based food and pharmaceutical products. In addition, this research provides new insights into the caramelization process, showing that caramelization can occur under low temperature (significantly below the literature reported melting temperature), albeit longer time, conditions.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Sacarose/química , Cromatografia Líquida de Alta Pressão/instrumentação , Temperatura Alta , Cinética , Estrutura Molecular
19.
J Food Sci ; 75(6): S271-8, 2010 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-20722948

RESUMO

Energy drinks have increased in popularity in recent years due to the claimed energy boost provided by functional ingredients. A multitude of functional ingredients have been utilized; however, there is limited research on their sensory effects in energy drink formulations. A 13-member descriptive analysis panel was conducted to investigate the effects on the sensory and rheological properties of 3 common functional ingredients-caffeine, ginseng, and taurine-in a noncarbonated model energy drink solution. Combinations of these functional ingredients at 3 levels (low, medium, high) were added to create a total of 27 different solutions (3 x 3 x 3 factorial design). Analysis of variance was performed to evaluate the sensory effects of the varying concentrations of functional ingredients in solution. Principal component analysis (PCA) was performed to summarize the relationship among the attributes and solutions. In general, high levels of caffeine in solution resulted in low ratings of fruity attributes and high ratings of bitter tea and fruit bitter attributes. The high level of ginseng in solution was characterized by high ratings of bitter attributes. A horns effect was observed as the sweet, artificial lemon-lime, pear, mango, and pineapple attributes were rated lower in intensity with increased ginseng levels. Taurine levels of up to 416 mg/100 mL had no significant effect on the sensory attribute ratings of the model energy drink solutions. These findings can be utilized to predict the changes in sensory characteristics when formulating energy drinks containing these popular functional ingredients.


Assuntos
Bebidas/análise , Cafeína/análise , Suplementos Nutricionais/análise , Panax/química , Extratos Vegetais/análise , Sensação , Taurina/análise , Adolescente , Adulto , Análise por Conglomerados , Feminino , Ginsenosídeos , Humanos , Masculino , Pessoa de Meia-Idade , Concentração Osmolar , Análise de Componente Principal , Reologia , Paladar , Viscosidade , Adulto Jovem
20.
J Food Sci ; 75(7): S341-7, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21535568

RESUMO

Ginseng is one of the most popular functional ingredients found in energy drink formulations. Although ginseng is known for its health benefits, ginseng is also notorious for imparting a bitter taste. Incorporating ginseng into beverages without the bitterness, while still maintaining its health benefits, is necessary for developing an acceptable product. Thus, the objectives of this study were to (1) identify effective treatments for minimizing the bitterness of ginseng in water base and model energy drink base solutions and (2) determine the sensory effects of incorporating different treatment levels to minimize the bitterness of ginseng. A series of pilot studies investigating bitterness reducing treatments were conducted, which included: congruent flavor addition, bitterness blocking agent incorporation, enzymatic modification, ingredient interaction, and complexation. Based on the results of a series of pilot studies, γ-cyclodextrin (γ-CD) and ß-cyclodextrin (ß-CD) complexation agents were identified as having the most potential. Effectiveness of the γ-CDs, ß-CDs, and combinations of γ- and ß-CDs were tested in 100 mL water and in 100 mL model energy drink base solutions containing 0.052 g 80% ginsenosides panax ginseng, using descriptive sensory analysis. Twelve trained panelists evaluated 42 solution treatments (3 treatments × 7 levels × 2 bases) for bitter attributes with and without nose clips. Overall, the most effective treatments were 0.09 g γ-CDs in 100 mL of solution and 1 g ß-CDs in 100 mL solution, which both reduced the bitterness intensity of the solutions by half. Incorporation of these levels of CDs in water and model energy drink base solutions containing ginseng will aid in the development of functional beverages that are more acceptable to a wider range of consumers.


Assuntos
Bebidas/análise , Aromatizantes/metabolismo , Ginsenosídeos/metabolismo , Panax/química , Raízes de Plantas/química , Adolescente , Adulto , Bebidas/economia , Feminino , Aromatizantes/economia , Alimentos Formulados/análise , Alimentos Formulados/economia , Humanos , Masculino , Pessoa de Meia-Idade , Concentração Osmolar , Projetos Piloto , Sensação , Paladar , Estados Unidos , Adulto Jovem , beta-Ciclodextrinas/economia , beta-Ciclodextrinas/metabolismo , gama-Ciclodextrinas/economia , gama-Ciclodextrinas/metabolismo
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