Citation
Hedayatnia, Simin
(2015)
Influence of different fat replacers and drying techniques on physicochemical characteristics and sensory attributes of regular and instant reduced-fat coffee creamer.
Masters thesis, Universiti Putra Malaysia.
Abstract
Coffee is one of the most popular soft drinks all around the world. Most of coffee
drinkers prefer to add creamer and/or whitener to their coffee before sunsumption.
Coffee creamers usually contains high amount of the saturated fat (15-40%).
Therefore, the frequent consumption of the whitened coffee can induce many health
issues (e.g. cardiovascular and chronic diseases) for coffee drinkers. In recent years,
the demand for low- and reduced-fat products has been extensively increased. The
aim of the present study was to formulate and characterize the reduced-fat coffee
creamer with the most desirable characteristics comparable with commercial
creamers.
The main objective of the present study was to investigate the effects of different
type and content of fat replacer (i.e. inulin, 0, 2.5, 5 and 7.5%; maltodextrin, 0, 15,
20 and 25%, w/w) as well as different drying techniques (i.e. spray drying, drum
drying and fluidized-bed drying) on physicochemical properties, microstructures, and
sensory attributes of the regular-and instant reduced-fat creamers. The regular coffee
creamers were produced by a single-stage drying (either spray drying or drum drying
only); while the instant reduced-fat coffee creamers were produced by a double-stage
drying (i.e. spray drying or drum drying along with fluidized-bed drying).
Physicochemical properties of all formulated creamers were compared with the
control (as a negative control) and commercial creamers (as a positive control).
The current study revealed that the physicochemical characteristics, microstructures,
and sensory attributes of both regular-and instant reduced-fat creamers were
significantly (p ≤ 0.05) influenced by both fat replacers and drying techniques.
Moisture content, water activity of regular-and instant creamers were notably
decreased by increasing the concentration of maltodextrin and inulin. This could be
due to significant (p ≤ 0.05) increase in solid content of samples. The bulk density of
regular-and instant creamers was dropped by increasing the content of target fat
replacers and enlarging the particle size. The current study revealed that the wettability, solubility, viscosity and glass transition temperature of the formulated
creamer were significantly (p ≤ 0.05) improved as the contents of inulin or
maltodextrin in the creamer formulation were increased.
The present study revealed that spray dried reduced-fat creamer had smaller spherical
or oval shape particles than the drum dried creamers; while drum dried samples had
much bigger particles with irregular shape. In this study, the drum-dried creamers
had darker colour (or lower lightness) than the spray-dried samples. This might be
because of its higher drying temperature and longer residence time. The drum-dried
creamers with markedly bigger particle size and lower moisture content had
considerably lower bulk density than the spray-dried creamer.
The current study revealed that the instant reduced-fat creamer had higher glass
transition temperature than the regular reduced-fat creamer. This could be explained
by the fact that the instant reduced-fat creamer had markedly lower moisture content
than the regular creamer because the application of fluidized-bed drying led to
decrease the moisture content, water activity, bulk density and stickiness. The
agglomeration induced by fluidized bed drying significantly increased the
reconstitution properties (wattability and solubility), viscosity and glass transition
temperature of the reduced fat creamer. The morphology analysis revealed that
agglomeration caused by fluidized-bed drying resulted in bigger particles with more
porous structure than the regular creamer. Finally, the current study revealed that the
instant spray-dried creamer (containing 25% maltodextrin and 7.5% inulin) had
better quality comparable with commercial creamer than the instant drum-dried
sample with similar formulation. The current study showed that instant spray-and
drum dried reduced-fat creamers containing high amounts of maltodextrin (25%,
w/w) and inulin (7.5%, w/w) had the most desirable characteristics among all
formulated creamers comparable with the commercial creamer.
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