trouble with extracting Date string from my data.

Hello,

I have trouble with extracting Date string from my each row data.

The date format I use is as the follows:
----------------------------------------------------------------------------
-----------
Index,Open,High,Low,Close # header
2011-11-01  9:00:00 ,248.50,248.95,248.20,248.70 ...
....
----------------------------------------------------------------------------
-----------

When I read the data with the below code,

data_min1 <- as.xts(read.zoo("E://log.txt", sep=",", FUN=as.chron,
header=TRUE))

the result is as the follows:

head(data_min1)

Open   High    Low  Close
(11/01/11 09:00:00) 248.50 248.95 248.20 248.70
(11/01/11 09:01:00) 248.70 249.00 248.65 248.85
(11/01/11 09:02:00) 248.90 249.25 248.70 249.15
(11/01/11 09:03:00) 249.20 249.60 249.10 249.60
(11/01/11 09:04:00) 249.55 249.95 249.50 249.60
(11/01/11 09:05:00) 249.60 249.85 249.55 249.75

I tried to extract Date object of each row(2011-11-01) and convert is as
string("2011-11-01").
But I couldn't.

Could you help me ?

Thanks in advance.

SK Park