Santhanee Puncha arnon. Changes in Properties of Edible Canna (Canna edulis Ker) Starch during Rhizomal Development and Characterization of the Canna Starch Blends. Doctoral Degree(Biochemical Technology). King Mongkut's University of Technology Thonburi. KMUTT Library.. : King Mongkut's University of Technology Thonburi, 2552-11-05.
Changes in Properties of Edible Canna (Canna edulis Ker) Starch during Rhizomal Development and Characterization of the Canna Starch Blends
Abstract:
In order to gain more knowledge on edible canna (Canna edulis Ker) plant
characteristics, change in properties of canna starches during rhizomal development and
canna starch utilization, edible canna (Vietnam variety) was planted in controlled
experimental plots at the RayongField Crops Research Center, Rayong, Thailand, for
12 months under supplemented irrigation. Development of canna plant and rhizomal
branching system were followed up. Canna rhizomes were collected monthly and used
for starch extraction. The effect of harvesting time on properties of canna starches was
studied. In addition, rhizomal segments harvested at 7th month after transplanting
(MAn were categorized based on stage of development into 4 groups; mother,
immature, premature and mature segment. The starch is isolated from the segments
belonging to these four groups were investigated for their properties. Finally, to expand
the canna starch utilization, the canna starch was blended with other starches (rice,
mungbean, and potato starches) in various ratios and properties of the starch blends
were investigated. These properties were then discussed in relation to the intrinsic
properties of individual starch and the relative granular size.
MAT. The average number of stems and leaves of matured plant were 8 stems and 70
leaves respectively, with 150-180 em in height. The edible canna forms a branching
rhizome which orients parallel to the surface of the ground. In mature plants, the canna
rhizome consists of several segments developed consecutively. At 6th MAT, the canna
plant is composed of 57 segments, which branch up to the 6th generation. The 3rd and 4th
generation segments were majority. Weight of rhizome per plant at 8th MAT was 40005000
g/rhizome wwb and increased to almost double at 12th MAT. The maximum yield
of starch at 18-20% wwb was found in rhizome harvested during 5th_8th MAT.
Microscopic view of mature segment revealed that the cross section area was
separated into two parts, the outer and inner parts, by 1-2 layers of endodermis cells and
a vast difference between two parts could be observed. The outer part (from epidermis
to endodermis) of rhizome segment was approximately 3 mm in thickness. It consisted
of 3-5 layers of epidermis cells, as well as parenchyma, sclerenchyma (sclereids and
fibers) and collenchyma cells. The inner part which functioned as a storage tissue was a
major part of rhizomal segments. It consisted mainly of parenchyma cells containing
very dense starch granules. A lot of vascular bundles scattered randomly among the
parenchyma cells and a distance between the bundles was in a range of 0.5-1.5 mm. A
large number of vascular bundles distributed throughout the inner core would be
responsible for a very active growing of canna rhizome.
Study on the effects of harvesting times on properties of starches revealed that
obvious changes in morphology (size and shape) of canna starches occurred during the
first 4th MAT, after that (5th_li b MAn their morphology was quite stable. The starch
extracted at 3rd MAT had much smaller size than the others. It also showed significant
differences in pasting and thermal properties from the other starches. The starches
isolated at 5th_12th MAT exhibited similar morphology, chemical composition, and
physicochemical properties. The results obtained suggested that starch quality depended
strongly on the developmental stage of starch granules. Once the starch granules are
fully developed (reach a mature stage), their property will not change to any further
extent.
Investigation on the properties of starches isolated from segments at different
stages of development indicated that size of starch granules increased with progressive
fully developed (reach a mature stage), their property will not change to any further
extent.
Investigation on the properties of starches isolated from segments at different
stages of development indicated that size of starch granules increased with progressive
development of segments from immature to premature and mature stages. Starch from
the mother segment contained a higher proportion of small-size granules than that from
other segments, and unusual features were observed on the surface of some granules.
Starches from different segments showed similar crystalline structures, and thermal and
pasting properties; however, some chemical compositions of starch from the mother
segment were different from others.
Canna, potato, mung bean and rice starches having mean granule size of 52, 48,
24 and 7 urn and gelatinization temperature of 72.4, 65.8, 70.1 and 75.2 ?C,
respectively, were used for evaluating the effects of relative granule size and
gelatinization temperature on pasting and gelation behaviors of starch blends. The
results from DSC and RVA analyses suggested that gelatinization behavior of starch
blend could be either additive or non-additive, and relative granule size rather than
gelatinization temperature of the starch components may be responsible for this
behavior. Gelation behavior of starch blends evaluated by setback value during cooling
down in RVA, and hardness value by texture analyzer, indicated the inexact additive
type for canna-potato starch blend and non-additive type for canna-mung bean and
canna-rice starch blends. The deviations from additive type were stronger with greater
differences in granule size. Therefore, the relative granule size was also supposed to
affect the gelation behavior of the starch blends.