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Journal of Tea Science Research 2013, Vol.3, No.1, 1-6
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4
Table 3 Short spacing values [Å] of polymorphic forms of cocoa butter
Reference
β′
β-V
β-VI
8
4.32 (s), 4.13 (s)
3.75 (m), 3.88 (w)
4.58 (s) 3.98 (ms) 3.65 (ms)
3.87 (m)
4.53 (vs), 3.67 (s), 3.84 (m)
9
4.35 (vs), 4.15 (vs)
3.97 (m), 3.81 (m)
4.58 (vs), 3.98 (s)
3.67 (w)
4.59 (vs), 3.70 (s)
Present study
CB
EIS
CBCH
EICH
ND
4.13 (vs), 3.74 (m)
4.35 (m), 3.97 (w)
4.36 (m), 3.78 (m)
ND
ND
ND
ND
4.59 (vs), 3.70 (s), 4.04 (m)
ND
4.53(S)
4.53 (S) 4.03 (m)
Note:
CB: cocoa butter; EIS: enzymatically interesterified sample; CBCH: chocolate containing CB; EICH: chocolate
containing CB and 10 percent EIS; Intensities estimated visually as, vs: very strong; s: strong; ms: medium strong; m:
medium; w: weak; ND: not detected
fats, which are used as CBRs, crystallize in the β′
form due to increase of the OOO and other
undesirable TAGS percentages (Ali et al., 2001;
Osborn and Akoh, 2002; Graef et al., 2005). As shown
in Table 1, in the current study, the EIS contained the
PLP, OOO, PLS and SOO (3.19%, 14.82%, 6.30%
and 4.81%, respectively), which are higher than those
of the CB (1.66%, 0.62%, 2.21% and 1.86%,
respectively), and can induce β′-polymorph formation
in this sample.
The results illustrated in Table 3 also show that CB
chocolate contains one crystal polymorph (β structure
with very strong and strong short spacing at 4.59 Å
and 3.70 Å, respectively), while CB and EI chocolate
contains two polymorph structures (β and β′ forms).
Consequently, blending 10% of EIS has probably no
adverse effect on β-crystal formation in the chocolate
product. This result is in accordance with that reported
by Osborn and Akoh (2002), who observed a mixture
of β and β′ crystal forms in chocolate prepared with
enzymatically interesterified beef tallow as cocoa
butter substitute.
2 Materials and Methods
Tea seeds (Lahijan variety) were harvested from
Iranian farms in Lahijan (in the North of Iran). The oil
was extracted by the solvent (Hexane) method after
grinding the seeds. Lypozime TL IM (1, 3-specific
lipase), a silica granulated
Thermomyces lanuginosus
lipase, and Malaysian CB were donated by
Novozymes A/S (Bagsvaerd, Denmark) and Minoo
Chocolate Factory (Tehran, Iran), respectively. TAG
standards were purchased from Larodan Fine
Chemicals AB (Malmo, Sweden).
Tea seed oil was hydrogenated in a laboratory reactor
(Zero Max, USA) at 180
℃
temperature, 400 rpm
mixing rate, and 0.4% Ni catalyst. Solid fraction (SF)
of the oil was prepared by dry fractionation in a test
chamber (Binder, Germany) at −20
℃
at 20~30 rpm
mixing rate for 4 h and centrifugation at 10000 g for
10 min at −20
℃
. Oil blend was then prepared by
blending hydrogenated tea seed oil and SF at 30:70
(wt/wt) ratio. Enzymatic interesterification of the oil
blend was carried out in screw-capped sealed glass
vials with a magnetic stirrer (700 rpm) at 60
℃
for 8 h
with 10% enzyme dosage by weigh of the oil.
Interesterified sample was immediately filtered
through Whatman filter paper No. 4 to remove fine
enzyme particles. The sample was then stored at
−24
℃
for further analysis (Zhang et al., 2001; Abigor
et al., 2003).
TAGS of samples were determined by reversed-phase
high-performance liquid chromatography (Younglin,
Acme 9000, South Korea) equipped with a refractive
index (RI) detector and a LiChrosphere RP C-18
column (25 cm length × 4 mm i.d, 4 µm particle size,
Spain). The mobile phase was acetone: acetonitrile
(60:40, v/v) at a flow rate of 0.6 mL/min. The column
and detector temperatures were set at 35
℃
and 40
℃
,
respectively. The samples were prepared at 5%
concentration with chloroform as the solvent and 10
μL of aliquots was injected into the column.
Individual peaks were identified by comparing the
retention times with those of TAG standards (AOCS,
1997). Each sample was analyzed three times and the
data was reported as average of percentage areas.
For preparation of dark chocolate samples, 50%
sieved sugar (mesh 100), 35% CB (CB was replaced