Dynamic method to characterize rehydration of powdered cocoa beverage: Influence of sugar nature, quantity and size (original) (raw)
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Factors affecting instant properties of powdered cocoa beverages
Food Chemistry, 2007
The increasing number of small and medium scale manufacturers of powder cocoa beverages (PCBs) in Nigeria requires relevant technical data useful in designing new and value added products from cocoa powder. This paper reports a preliminary study carried out to determine how some physical and chemical factors relate to the instant properties of some commercial samples of PCBs produced in Nigeria. The levels of chemical component like moisture, fat and sugar in the PCBs varied from 0.8 to 3.6%, 2.0 to 10.4% and 52.4 to 90.5%, respectively. Physical properties like the bulk density, angle of repose, average particle size and uniformity index of the products varied from 0.49 to 0.81 g/cm 3 , 25.0 to 37.7o, 0.031 to 0.796 mm and 6.25 to 7.44, respectively. Instant properties such as wettability, dispersibility and solubility ranged from 10.7 to 21.7 s, 50.0 to 94.5% and 44.2 to 76.6%, respectively. These properties differed significantly (p<0.05) among the 10 commercial samples of PCB studied. Sugar (sucrose) content of products had the most significant (p<0.05) main effect on their instant properties followed by the fat content. Wetting time showed a significant (p<0.05) negative linear correlation with sugar content. Agglomeration increased the average particle size, which correlated negatively with uniformity index. The instant properties of fine PCBs (average particle size < 0.294 mm) were more predictable than the agglomerated samples.
Food and Bioprocess Technology, 2011
Characterization of flow properties represents a crucial step in the production of powdered composite mixtures. Mixing of cocoa powders with different sugars is the first step in the production of this type of beverages, which leads to a change in the mixtures flow properties. The objective of this work was firstly to determine the physical properties of non-agglomerated powdered cocoa and sugar mixtures and, after that, to determine which physical properties of cocoa powders are influenced by sugar addition and in what way they are influenced by sugars. Mixtures were formulated by two cocoa powders containing different amounts of fat and 11 different kinds of sugar or sweetener. A significant change was found in the median diameter, poured bulk density, compression and decompression force of the mixtures compared to the sole components' physical properties. All the mixtures display a decreasing compaction coefficient with increase of flow speed, which indicates that these powder mixtures flow more freely at higher transport speeds. An increase of cake height ratio was detected in all the mixtures, indicating that all the mixtures were susceptible to caking and that they formed a strong cake. Insolubility of the mixtures was influenced significantly by the median diameter of the sugar particles added to the mixture. Addition of sugars and sweeteners to the cocoa powder reduced the red and yellow colour components, but the type of sugar or sweetener did not produce a considerable difference in the colour of the cocoa drink mixtures.
Journal of Food Engineering, 2010
The objective of this research was to evaluate the effects of the steam agglomeration process variables on the characteristics of cocoa beverage powders. A pilot scale agglomerator was used in the tests. For the cocoa beverage powder formulated with granulated sugar, most common commercial product, the increase in solids feed rate (400-700 g/min) led to a decrease in the mean particle diameter (400 g/min-564.70 lm, 700 g/min-438.40 lm) and an increase in the dryer rotation (12-52 rpm) led to an increase in the product moisture (12 rpm-1.52% w.b., 52 rpm-1.88% w.b.). The changing from 1.0 Â 10 2 to 1.8 Â 10 2 kPa of the vapor pressure resulted in an increase in moisture of the cocoa beverage powder (1.0 Â 10 2 kPa-1.46% w.b., 1.8 Â 10 2 kPa-1.94% w.b.) and the intensification of the yellow color of the product (1.0 Â 10 2 kPa-14.51, 1.8 Â 10 2 kPa-15.17).
Particle Size Distribution Applied to Milk Powder Rehydration
Química Nova, 2020
Besides increasing shelf life of fluid milk, milk powder has physical and functional properties that allow it to be used as ingredient. The rehydration process is complex and happens in four steps: wettability, sinkability, dispersibility and solubility. Works have been conducted aiming at the development of an easier, more convenient and reproducible method to evaluate the dissolution properties of dairy powders. Therefore, the aim of this work was to evaluate dispersibility and solubility through particle size distribution in order to establish a new rehydration index for whole milk powder. The particle size distribution and morphological characteristics of seven samples of milk powder (from A to G) were analyzed. Samples F and C differed from the others which formed a similar group. Principal component analysis divided the samples into three different groups, allowing the indication of an efficient rehydration index to determine the powders dispersability.
Moisture-induced caking of beverage powders
Journal of the Science of Food and Agriculture, 2011
BACKGROUND: Beverage powders can exhibit caking during storage due to high temperature and moisture conditions, leading to consumer dissatisfaction. Caking problems can be aggravated by the presence of sensitive ingredients. The caking behaviour of cocoa beverage powders, with varying amounts of a carbohydrate sensitive ingredient, as affected by climate conditions was studied in this work. Sorption isotherms of beverage powders were determined at water activities (a w) ranging from 0.1 to 0.6 in a moisture sorption analyser by gravimetry and fitted to the Brunauer-Emmett-Teller (BET) or the Guggenheim-Anderson-de Boer (GAB) equation. Glass transition temperatures (T g) at several a w were analysed by differential scanning calorimetry and fitted to the Gordon-Taylor equation. Deduced T g = f(a w) functions helped to identify stability or caking zones. Specific experimental methods, based on the analysis of mechanical properties of powder cakes formed under compression, were used to quantify the degree of caking. Pantry tests complemented this study to put in evidence the visual perception of powder caking with increasing a w. RESULTS: The glass transition approach was useful to predict the risks of caking but was limited to products where T g can be measured. On the other hand, quantification of the caking degree by analysis of mechanical properties allowed estimation of the extent of degradation for each product. CONCLUSION: This work demonstrated that increasing amounts of a carbohydrate sensitive ingredient in cocoa beverages negatively affected their storage stability.
Determination of the cohesion, powder flow speed dependency and caking tendency of cocoa powders
Academic Perspective Procedia, 2019
Cocoa is one of the most popular foodstuffs known for centuries and cocoa powders are particularly exposed to caking, a phenomenon of agglomeration of solid particles that disrupt powder functionality. This study aimed to identify the main powder flow characteristics such as caking, cohesion and powder flow speed dependency of cocoa powders, according to their fat content. The loose and tapped bulk density, as well as Carr ratio of cocoa powders, was determined as bulking properties for comparing and interpreting the flowability. The caking was observed in all three samples. With increasing fat content, a decrease in the powder flowability was detected. The mean cake strength of the low fat, reduced fat and full-fat cocoa powders was recorded as 110.42±1.71; 164.175±1.75 and 207.96±0.93, respectively. These results suggest that the fat contents of the food powders may be a useful parameter to describe the powder flowability.
Assessment of measurement characteristics for rehydration of milk protein based powders
Rehydration is an important powder property and is regarded as a critical issue by the dairy industry. Traditional powder rehydration measurements are relatively empirical with poor reproducibility. Thus, more reliable techniques tailored for dairy powders should be developed based on varied rehydration behaviours and applications. In this paper, a critical assessment to identify the measurement characteristics of milk protein powder rehydration is presented. Milk protein based powders were used as model systems. Four different wettability measurements (Immersion, Capillary rise, Condensation and Spreading) and four different dispersibility measurements (Dispersibility Index, Light scattering of particles in suspension, Light transmission and Conductivity of suspension) are compared and analysed. The results show that the method based on immersional wetting procedure is only appropriate for skimmed milk powder while the method for capillary rise wetting is more useful for the agglomerated milk protein powders with porous structures. Contact angle changes in the spreading wetting approach is found to be a straightforward technique to show the hydrophobicity or hydrophilicity of milk protein powders. If compared with traditional dispersibility measurements, light transmission of suspension is suitable to reflect optical properties of slow dispersion process. Light scattering methods can also be used to measure the dynamic size change of particles during the dispersion process. Furthermore, the conductivity of suspensions is a useful indicator to quantify the dispersibility indirectly by the release of minerals during rehydration. In summary, it is necessary to understand the specialities and applications of dairy powders before choosing the appropriate rehydration measurement methods.
Journal of Agricultural and Food Chemistry, 2010
In the present study the physical properties of powdered cocoa drink mixtures prepared from two cocoa powders with various fat contents and different sweeteners, as well as the bioactive content and sensory properties of cocoa drinks prepared from them, were investigated. Particle size and bulk density of the used sugars and sweeteners, as well as the formulated mixtures, were determined and their influence on cohesion index was evaluated. To compare the content of polyphenols in the formulated cocoa drink mixtures, UV-vis spectrophotometric methods were applied. Antioxidant capacity of cocoa drinks was evaluated by using the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2 0 -azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), and ferric reducing/antioxidant power (FRAP) assays. The analyzed cocoa drinks prepared from cocoa powder and different sugars or sweeteners delivered a substantial content of cocoa antioxidants, whereas the content and the type of sugar or sweetener did not affect the polyphenolic constituents of the prepared cocoa mixtures. Cocoa powder mixtures prepared with the cocoa powder containing higher fat content (16-18%) generally provided lower total polyphenol, total flavonoid, flavan-3-ol, and proanthocyanidin contents, compared to the mixtures prepared with cocoa containing lower fat content (10-12%). Total phenol content of cocoa drinks prepared from experimental mixtures ranged from 320.45 to 480.45 mg of GAE/L, whereas the ranking of the antioxidant capacities varied depending on the used assay, and the fat content of cocoa powder did not affect the antioxidant capacity of cocoa mixtures. As determined, the addition of sugar to cocoa powder increases the solubility and dispersibility of the mixtures; on the basis of their cohesion index all mixtures can be classified as very cohesive or hardened/extremly cohesive. Results of the sensory evaluation, using the 9-point hedonic scale, showed that there was a preference for the cocoa drinks made with sweeteners (aspartame/acesulfame K and stevia extract), and there was a significant difference in the sensory attributes between the experimental mixtures and the control. The displayed results indicate the significant potential of using alternative sweeteners for the preparation of cocoa drink mixtures, which may provide good physical and sensory properties and also enhance the already existing beneficial effects of cocoa.
Chocolate beverage powders (CBPs) were produced from alkalized cocoa powder (ACP) at 10-30% and soy lecithin (SL) at 0-4%. Response surface methodology (RSM) was used to determine the optimum level of ACP and SL on sedimentation, wettability, bulk density, despersibility, moisture content andjlavor acceptability. SL was efective on wettability, and it also showed an optimum level for sedimentation and bulk density, while ACP was found to be signiJicant for all physical properties. For sensory evaluation, jlavor was acceptable at 20% ACP level soy taste was detected by panelists in CBPs with high SL and low ACP contents. It was found that as the ACP content was increased the soy taste of CBPs decreased. For overall physical characteristics, the optimum levels of 20% of ACP and 2-4% of SL were selected.