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The physicochemical properties of microwave-assisted encapsulated anthocyanins from Ipomoea batatas as affected by different wall materials.

Mohd Nawi N, Muhamad II, Mohd Marsin A - Food Sci Nutr (2015)

Bottom Line: Results indicated that encapsulated powder with the GA and MD combination presented better quality of powder with the lowest value of moisture content and water activity.With respect to morphology, the microcapsule encapsulated with GA + MD showed several dents in coating surrounding its core material, whereas other encapsulated powders showed small or slight dents entrapped onto the bioactive compound.Colorimetric analysis showed changes in values of L, a*, b*, hue and chroma in the reconstituted powder compared to the initial powder.

View Article: PubMed Central - PubMed

Affiliation: Bioprocess Engineering Department, Faculty of Chemical Engineering, Universiti Teknologi Malaysia Johor Bahru 81310 Skudai, Johor, Malaysia.

ABSTRACT
This study focuses on the impact of different wall materials on the physicochemical properties of microwave-assisted encapsulated anthocyanins from Ipomoea batatas. Using the powder characterization technique, purple sweet potato anthocyanin (PSPAs) powders were analysed for moisture content, water activity, dissolution time, hygroscopicity, color and morphology. PSPAs were produced using different wall materials: maltodextrin (MD), gum arabic (GA) and a combination of gum arabic and maltodextrin (GA + MD) at a 1:1 ratio. Each of the wall materials was homogenized to the core material at a core/wall material ratio of 5 and were microencapsulated by microwave-assisted drying at 1100 W. Results indicated that encapsulated powder with the GA and MD combination presented better quality of powder with the lowest value of moisture content and water activity. With respect to morphology, the microcapsule encapsulated with GA + MD showed several dents in coating surrounding its core material, whereas other encapsulated powders showed small or slight dents entrapped onto the bioactive compound. Colorimetric analysis showed changes in values of L, a*, b*, hue and chroma in the reconstituted powder compared to the initial powder.

No MeSH data available.


Graph of water activity using different encapsulating agent.
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fig02: Graph of water activity using different encapsulating agent.

Mentions: Water activity is a very essential index for microwave-assisted powders as it determines the shelf life of the product. Water activity is defined as the ratio of vapour pressure of water in a food system to vapour pressure of pure water at the same temperature. Water activity varies with moisture content as it measures the availability of free water in a food system which is responsible for any biochemical reactions, whereas the moisture content represents the composition of water in a food system (Quek et al. 2007). From Fig.2, the range of water activity of the powders produced from I. batatas is very slight, between 0.5 and 0.52. This range is considered microbiologically stable. Powders produced with the combination gum arabic and maltodextrin showed the lowest water activity, followed by those produced with maltodextrin alone. Particles produced with gum arabic showed the highest water activity. Such results are similar and in agreement with those of moisture content and the differences on aw values can also be related to the chemical structure of these agents. Higher water activity indicates that there is more free water available for microorganism growth and biochemical reactions and thus shorter product shelf life (Tonon et al. 2009). Basically, food with aw less than 0.6 is microbiologically stable (Endut and Osman 2009). A similar range of aw values were obtained by Quek et al. (2007) for spray-dried watermelon.


The physicochemical properties of microwave-assisted encapsulated anthocyanins from Ipomoea batatas as affected by different wall materials.

Mohd Nawi N, Muhamad II, Mohd Marsin A - Food Sci Nutr (2015)

Graph of water activity using different encapsulating agent.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4376403&req=5

fig02: Graph of water activity using different encapsulating agent.
Mentions: Water activity is a very essential index for microwave-assisted powders as it determines the shelf life of the product. Water activity is defined as the ratio of vapour pressure of water in a food system to vapour pressure of pure water at the same temperature. Water activity varies with moisture content as it measures the availability of free water in a food system which is responsible for any biochemical reactions, whereas the moisture content represents the composition of water in a food system (Quek et al. 2007). From Fig.2, the range of water activity of the powders produced from I. batatas is very slight, between 0.5 and 0.52. This range is considered microbiologically stable. Powders produced with the combination gum arabic and maltodextrin showed the lowest water activity, followed by those produced with maltodextrin alone. Particles produced with gum arabic showed the highest water activity. Such results are similar and in agreement with those of moisture content and the differences on aw values can also be related to the chemical structure of these agents. Higher water activity indicates that there is more free water available for microorganism growth and biochemical reactions and thus shorter product shelf life (Tonon et al. 2009). Basically, food with aw less than 0.6 is microbiologically stable (Endut and Osman 2009). A similar range of aw values were obtained by Quek et al. (2007) for spray-dried watermelon.

Bottom Line: Results indicated that encapsulated powder with the GA and MD combination presented better quality of powder with the lowest value of moisture content and water activity.With respect to morphology, the microcapsule encapsulated with GA + MD showed several dents in coating surrounding its core material, whereas other encapsulated powders showed small or slight dents entrapped onto the bioactive compound.Colorimetric analysis showed changes in values of L, a*, b*, hue and chroma in the reconstituted powder compared to the initial powder.

View Article: PubMed Central - PubMed

Affiliation: Bioprocess Engineering Department, Faculty of Chemical Engineering, Universiti Teknologi Malaysia Johor Bahru 81310 Skudai, Johor, Malaysia.

ABSTRACT
This study focuses on the impact of different wall materials on the physicochemical properties of microwave-assisted encapsulated anthocyanins from Ipomoea batatas. Using the powder characterization technique, purple sweet potato anthocyanin (PSPAs) powders were analysed for moisture content, water activity, dissolution time, hygroscopicity, color and morphology. PSPAs were produced using different wall materials: maltodextrin (MD), gum arabic (GA) and a combination of gum arabic and maltodextrin (GA + MD) at a 1:1 ratio. Each of the wall materials was homogenized to the core material at a core/wall material ratio of 5 and were microencapsulated by microwave-assisted drying at 1100 W. Results indicated that encapsulated powder with the GA and MD combination presented better quality of powder with the lowest value of moisture content and water activity. With respect to morphology, the microcapsule encapsulated with GA + MD showed several dents in coating surrounding its core material, whereas other encapsulated powders showed small or slight dents entrapped onto the bioactive compound. Colorimetric analysis showed changes in values of L, a*, b*, hue and chroma in the reconstituted powder compared to the initial powder.

No MeSH data available.