1

Complexation of curcumin with soy protein isolate and its implications

on solubility and stability of curcumin

SourceSource：： Food Chemistry 130 (2012) 960–965

SpeakerSpeaker：： Syu,Yu-LianSyu,Yu-LianStudent ID No.Student ID No.：： 100751106100751106

DateDate：： 101101年年 0303月月 2222日日

2

Background

• Curcumin (bis-a,b-unsaturated b-diketone), commonly called as diferuloylmethane, is a low-molecular-weight, natural polyphenolic compound found in the rhizome of turmeric (Curcuma longa).

• It has a wide range of pharmacological activities including anti-inflammatory, antioxidant, antiproliferative and antiangiogenic (Anand, Kunnumakkara, Newman, &Aggarwal, 2007) properties.

3

IntroductionIntroduction

• The effectiveness of a functional food depends on preserving the activity of the bioactive molecule.

• Moreover, the activity depends on its solubility, stability, absorptionand bioavailability.

• The effectiveness of nutraceutical products in preventing diseasesdepends on preserving the bioavailability of the active ingredients.

4

Introduction(Cont.)Introduction(Cont.)

• Protection of the bioactive compounds against conditions encountered in food processing and in the gastrointestinal tract (pH, presence of enzymes and other nutrients) is of paramount importance (Bell, 2001).

• By encapsulation, a bioactive compound can be protected from environmental destructive factors, solubilised and delivered in a controlled manner.

5

Introduction(Cont.)Introduction(Cont.)

• In searching food-grade materials to form complexes with curcumin, we focused on soy protein isolate (SPI).

• Soy proteins are used extensively in food manufacturing, because of their functional properties, low cost, availability and high nutritional value.

6

Aim

• The aim of this study was to investigate the potential of SPI as a carrier for curcumin.

• An approach was made to enhance the water solubility and stability of curcumin by complexing it with SPI.

7

Materials and methods

8

Materials• Curcumin was purchased from ICN biomedicals, Inc.

(Aurora,Ohio). • 2, 2-diphenyl-1-picrylhydrazyl (DPPH) was from Sig

ma Aldrich Chemicals Co. (St. Louis, MO). • Curcumin stock solution was prepared in methanol. • Absorbance measurements were made on a Shimadzu

1601 double beam spectrophotometer,using a 10 mm path length quartz cell.

9

Preparation of soy protein isolateSoy protein isolate (SPI)

10-fold distilled water adjusted to pH 8 with 2 M NaOH

stirred for 1hr

supernatantadjusted to pH 4.5

with 2 M HCl

soy protein curdcollected by centrifugation(8000 rpm, 20 min)

4-fold distilled wateradjusted to pH 7 with 2 M NaOH

freeze-drying

10

Complexation of curcumin with SPI

curcumin was added to 5% (w/v) SPI solution

homogenizer for 10 min

magnetic stirrer overnight

centrifugation (8000 rpm, 20 min)

supernatant

spray-dried

SPI–curcumin complex powder.

11

Stability measurements

• To study the stability, SPI–curcumin complex was dissolved in water, simulated gastric and intestinal fluids.

• The stability of curcumin was calculated by measuring the absorbance at 425 nm at different time intervals.

• Simulated gastric and intestinal fluid was prepared without enzyme as followed by Maltais et al. (2009).

12

Fluorescence measurement

curcumin 5 μM in a Tris–HCl buffer pH 7.4 SPI from 0 to 5 mg/ml

Fluorescence spectrophotometry

SPI solutions 5 μM in a Tris–HCl buffer pH 7.4

Fluorescence spectrophotometry

13

Foaming capacity• Foaming capacity of samples was determined ac

cording to the method of Sathe and Salunkhe (1981).

Samples

measuring cylinder

Homogenizer for 1 min

14

Emulsion capacity

3 ml proteinsolutions (1% w/v) 1 ml of refined groundnut oil

50 mM Tris–HCl buffer (pH 8)

vortexed for 1min

50 μl dissolved in 5 ml of 0.1% (w/v) SDS.

Absorbance 500nm

• The emulsion capacity of samples was determined according to the method of Pearce and Kinsella (1978).

15

The antioxidant activity of the samples were measured by the

following methods

16

DPPH radical scavenging activity

Samples

dissolved in water( 0–10 mg/ml)

0.5 ml of the sample

added to 1 ml 0.2 mM DPPH then mixed vigorously

After incubation for 30 min

centrifuged (8000 rpm 10 min)

UV-spectrophometer (517nm)

dissolved in water( 0–10 mg/ml)

0.5 ml of the sample

added to 1 ml 0.2 mM DPPH

After incubation for 30 min

centrifuged (8000 rpm 10 min)

UV-spectrophometer (517nm)

Samples

dissolved in water( 0–10 mg/ml)

0.5 ml of the sample

added to 1 ml 0.2 mM DPPH

After incubation for 30 min

centrifuged (8000 rpm 10 min)

UV-spectrophometer (517nm)

then mixed vigorously

Samples

dissolved in water( 0–10 mg/ml)

0.5 ml of the sample

added to 1 ml 0.2 mM DPPH

After incubation for 30 min

centrifuged (8000 rpm 10 min)

UV-spectrophometer (517nm)

then mixed vigorously

Samples

dissolved in water( 0–10 mg/ml)

0.5 ml of the sample

added to 1 ml 0.2 mM DPPH

After incubation for 30 min

centrifuged (8000 rpm 10 min)

UV-spectrophometer (517nm)

17

• DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity was measured using the method of Yen and Wu (1999).

DPPH radical scavenging activity(cont.)

18

Reducing power• Reducing power was determined by the method of

Oyaizu(1986).

The sample solution (0.1 ml, 0–10 mg/ml)

0.4 ml 0.2 M phosphate buffer (pH 6.6) and 0.5 ml 1% (w/v) potassium ferricyanide

mixed

Heating (50 20min)℃

added to (0.5 ml) of 10% (w/v) TCA centrifuged (3000 rpm 10 min)

19

Supernatant(0.5ml)

mixed with 0.5 ml of distilled water and 0.1 ml 0.1% (w/v) ferric chloride

absorbance was read at 700 nm.

Reducing power(Cont.)

20

Statistical analysis• For all the measurements, a minimum of triplicates

were taken for data analysis. • Using the Origin 6.1 software, all of the values were

plotted. • Data were expressed as means ± standard deviations.• One way analysis of variance (ANOVA) was

employed to identify significant differences (p < 0.05) between data sets using software Origin 6.1.

21

Results and discussion

22

23

24

25

26

27

28

29

30

31

32

Conclusion

• In the present study, it was shown that SPI can form complexes with curcumin.

• The antioxidant activity of SPI increases after complexation with curcumin.

33

References

• Vivek, R. Y., Sahdeo, P., Ramaswamy, K., Jayaraj, R., Madan, M. C., Lauri, V., et al.(2010). Cyclodextrin-complexed curcumin exhibits anti-inflammatory and antiproliferative activities superior to those of curcumin through higher cellular uptake. Biochemical Pharmacology, 80, 1021–032.

• Maltais, A., Remondetto, G. E., & Subirade, M. (2010). Tabletted soy protein cold-set hydrogels as carriers of utraceutical substances. Food ydrocolloids, 24(5),518–524.

• Efstathia, I. P., Spyros, J. K., & Vaios, T. K.(2011). Stability and release properties of curcumin encapsulated in Saccharomyces cerevisiae, b-cyclodextrin and modified starch. Food Chemistry, 125, 913–922.

• Leung, M. H. M., & Kee, T. W. (2009). Effective stabilization of curcumin by association to plasma proteins: Human serum albumin and fibrinogen.Langmuir, 25(10), 5773–5777.

34

Thank you for listening