Patent Application
20070269570
The novel compounds can be prepared from (epi-)catechin (2 mmol) with a reducing sugar such as glucose or galactose (20 mmol) with 1440 mg of K2C03 added to 25 ml solution (in water, the pH is approx. 10) and reacted at 80° C. for 2.0 min.
The resulting reaction flavor is finally freeze-dried. The individual compounds may be extracted from the reaction flavor by solvent extraction with aqueous acetone or methanol and then isolated by chromatography on RP-18 material using water-methanol gradients. Finally, the compounds were evaporated in vacuo, and the remaining solvent carefully removed by double freeze-drying.
Sensory tasting (5 persons) showed that alkalized cocoa powder (5 g/200 ml) +50 ppm of 8-C-glycosylated catechin was perceived as less bitter and less astringent than a reference without addition.
Non-alkalized cocoa powder (5 g/200 ml) +50 ppm of 8-C-glycosylated catechin was perceived as milder and less astringent than a reference without addition.
Grape seed extract (2000 ppm)+ca. 10 ppm 8-C-glucosylated catechin was tasted against reference of grape seed extract (2000 ppm)and tasters found a decrease in astringency.
Theobromine (600 ppm)+ca. 10 ppm 8-C-glucosylated catechin. The tasters did not a perceive a decrease in bitterness intensity but noted a delay in bitterness perception compared to pure theobromine.
77 mg of a solution of catechin-8-C-glucoside dissolved in propylene glycol (7.8%) was added to 20 g of molten dark chocolate with strong astringent taste characteristics. After solidification, the chocolate was tasted against a non-treated reference chocolate. It was perceived that the astringency was lower while bitterness remained unchanged. 4 of 5 tasters noticed a “smoothing out” effect, meaning the bitterness and astringency is not masked but is not perceived so much as an upfront hit and does not linger as much as from the blank.
8 persons tasted alkalized cocoa powder at 5 g/200 ml against alkalized cocoa powder (5 g/200 ml)+50 ppm Cat-6-C-Glc (ppm refer to 1 kg of water). It was found that there was a lower maximum bitterness intensity than in the control sample, a flat bitterness profile and a “softer bitterness quality
The modified product of example 6 was further compared to alkalized cocoa powder (5 g/200 ml)+50 ppm Epicat-6-C-Glc (ppm refer to 1 kg of water). The sensory evaluation revealed a lower maximum bitterness intensity than control, a flatter bitterness profile and a “softer” bitterness quality.
The modified product of example 6 was further compared to alkalized cocoa powder (5 g/200 ml)+50 ppm Cat-6,8-C-di-Glc (ppm refer to 1 kg of water). The sensory evaluation revealed a lower maximum bitterness intensity than control, a flatter bitterness profile and a “softer” bitterness quality.
The examples were repeated with the catechin and epicatechin galactosides and the same sensory results were obtained. As a result, galactose as a reducing sugar to produce the sugar addition products is equally effective as glucose.
Food ingredients were prepared starting from green tea extract (5 g) or grape seed extract (5 g) by reaction with glucose (4 g) and 3% K2C03 in 100 ml of water. The reaction was done at 80° C. for exactly 20 min. The resulting flavour reaction mix was freeze-dried to obtain a dark red-brown mass which was then added to astringent tasting chocolate at various levels. In a first screening sensory tasting, the optimum level of addition was identified as 300 ppm. The resulting chocolate showed a cleaner taste with reduced astringency compared to a non-treated reference sample.
Ingredients prepared from grape seed extract and tea extract in such a manner when added to dark chocolate at 330 ppm decreased the perceived sensory perception of astringency in the dark chocolate.
The following experiments were conducted to demonstrate the utility of various starting materials. The table indicates the concentration [mg/kg]a based on a dry weight basis in cocoa nibs:
aConcentrations are given as the mean of duplicates.
bt.a. trace amounts.
cn.d. not detected.
The table below indicates the concentrations ([mg/kg]a dry weight) of sugar addition products (C-glycosides) obtained when applying different alkalization processes to cocoa nibs(glc indicates glucose; gal indicates galactose):
aConcentrations are given as the mean of duplicates.
bt.a. trace amounts.
cIn all samples c-6, 8-C-gal was detected in trace amounts.
dn.d. not detected.
The modification of the cocoa nibs in order to achieve higher quantities of sugar addition products was done as follows:
time 50 min, T=80° C., m=10 g glucose, 4.4% K2CO3 (200 g of cocoa nibs).
If other sources of flavonoids other cocoa nibs are used, reaction parameters need to be adjusted to achieve maximum conversion rates to the sugar addition products.
To investigate the influence of taste modification of (−)-catechin-8-C-β-D-glucopyranoside on theobromine in comparison to the aglycons (+)-catechin and (−)-epicatechin as well as further C-glycosides like apigenin-8-C-β-D-glucopyranoside (vitexin) and apigenin-6-C-β-D-glucopyranoside (isovitexin), theobromine (3 mmol/L) was spiked with different concentrations of (−)-catechin-8-C-β-D-glucopyranoside, (+)-catechin, (−)-epicatechin as well as apigenin-8-C-β-D-glucopyranoside (vitexin) and apigenin-6-C-β-D-glucopyranoside (isovitexin). The results are summarized in the table below:
aEight panelists were asked to compare a solution of theobromine (3 mmol/L) with the a solution of theobromine (3 mmol/L) spiked with different amounts (−)-catechin-8-C-β-D-glucopyranoside, (+)-catechin, (−)-epicatechin, vitexin, and isovitexin by means of a triangel test.
bIf the sample was detected correctly (c.f. a), the changes in taste and taste intensities should be evaluated in comparison to the reference solution of theobromine, which was evaluated with a bitterness of 5.0.
| Number | Date | Country | Kind |
|---|---|---|---|
| EP 06 010 370.2 | May 2006 | EP | regional |
