| Summary: | Black rice (Oryza sativa L. indica) is one of cereal comodities consider as
source of anthocyanin. One of the obstacle of using anthocyanins as food colorant
is their low stability. Copigmentation and encapsulation can enhance the color
stability of anthocyanin. Flavonoid extract obtained from bilimbi leaves
(Averrhoa bilimbi) and sow thistle leaves (Sonchus arvensis) were used as
copigment.
Study the color characteristic of anthocyanin was investigated in buffer pH
1-7, anthocyanin content and total flavonoid was measured using pH-differential
method and AlCl3 spectrophotometric respectively, the copigmentation effect was
observed from bathochromic and hyperchromic shift. Degradation rate constant
and half-time was obtained from anthocyanin content, color change of
encapsulated and absorbance of encapsulated anthocyanin in buffer pH 3 was also
measured during storage.
Anthocyanin content of black rice was 105,11±7,76 mg/100g (db). Color
characteristic from black rice anthocyanin was greatly influenced by pH. Total
flavonoid of bilimbi leaves and sow thistle leaves extract was 2,17±0,15% mg
extract and 1,18±0,05% mg extract respectively. Purification increased the total
flavonoid content of bilimbi leaves and sow thistle leaves extract to 2,75±0,15%
mg extract and 1,52±0,04% mg extract respectively. Flavonoid extract can be
used as copigment and show copigmentation effect as batochromic and
hipercromic at pH 1 and 3. Copigment significantly lowered the degradation rate
of anthocyanin and extended its half-time. Combination copigmentation and
encapsulation decreased color loss due to photooxidation and thermal
significantly.
|
|---|