Int J Food Sci Nutr 1995 Feb;46(1):3-12

Influence of processing and cooking of carrots in
mixed meals on satiety, glucose and hormonal
response.

Gustafsson K, Asp NG, Hagander B, Nyman M, Schweizer T

The influence of processing and cooking on the metabolic response to
carrots in mixed meals was explored in two consecutive harvest years.
The contribution of dietary fibre (4.4 g 1989 and 6.6 g 1990) from
carrots was chosen to be different in order to compare effects with
varying doses. The meals, composed of carrots, creamed potatoes, meat
balls, lingonberry jam, white bread and light beer, were served in the
morning after an overnight fast to 10 healthy male volunteers. Carrots
were investigated raw, processed (blanched and frozen) and variously
cooked (thawed, boiled and microwaved). The amount of dietary fibre
from the vegetable, and the content of energy, digestible carbohydrates,
fat and protein were similar in the meals compared. Significantly lower
glucose, insulin and C-peptide responses and higher satiety scores were
elicited with raw carrots than with microwaved ones, harvest year 1989.
The next year, with a higher dietary fibre intake from carrots, there
were significant effects of processing only on the glucose response.
Plasma beta-carotene levels tended to be higher postprandially with
raw carrots than with microwaved ones. Hence, ordinary processing and
cooking of vegetables can affect the metabolic response to a mixed
meal. However, the influence seems to be varying and of minor
importance in ordinary meals. Increasing vegetable portions entailing a
higher soluble fibre content and a higher viscosity could further reduce
the influence of processing.