Influence of processing methods on the bioavailability of beta-carotene in selected foods
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Date
2003
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Department of Home Science, College of Agriculture, Vellayani
Abstract
The study entitled "Influence of processing methods on the
bioavai labil ity of 13-carotene in selected foods" was carried out with the
objective to envisage the current consumption pattern of 13-carotene rich
foods and to assess the influence of selected processing techniques on the
bioavailability of 13-carotene.
The consumption pattern of carotene rich foods was elucidated by a
dietary survey conducted among fifty urban and fifty rural homemakers
from Thiruvananthapuram district.
Personal profile of the respondents indicated that majority were
middle aged Hindu women belonging to nuclear middle income families
Most of the families were small sized, with less than five members. The
monthly food expenditure pattern indicated that urban families spent more
amount on food compared to rural households.
With regard to frequency of use of 13-carotene rich foods, locally
available green leafy vegetables like agathi, drumstick leaves and
chck kurrnanis were consumed more by rural families than urban as these
items were available from their homesteads. Amaranth (red and green)
though purchased mostly from markets and shops was preferred equally by
households of both areas. Moreover, urban families were found to prefer
conventional vegetables like carrot, yam, pumpkin and fruits like dates
which arc readily accessible from the markets. Cluster beans a low cost 13-
carotene rich vegetable was preferred by rural families. Seasonally
available jack fruit and locally available papaya were observed to be more
frequently consumed by rural households, while mango, orange and
tomato were used in a similar frequency rate by both the groups.
The ten commonly consumed 13-carotene rich vegetables identified
through survey included green leafy vegetables like agathi, amaranth (red
and green), drumstick leaves and chekkurmanis, other vegetables and
fruits like carrot, yam, cluster beans, pumpkin and tomato (ripe).
Daily meal pattern of the selected rural and urban families assessed
by recallmethod revealed that the p-carotene content of the diets of most
of the families were inadequate, as it could meet only less than 75 per cent
of their RDA. Meanwhile a small group were able to obtain fJ-carotene
even above 100 per cent of RDA.
The dietary adequacy of p-carotene of the daily diet of homemakers
were specifically studied as women are more susceptible to poor nutrition
for several reasons. It was found that majority of women (both urban and
rural) had diets deficient in fJ-carotene and only a small group had
satisfactory intake of this nutrient meeting 83-100 per cent of RDA. Also
very few homemakers were observed to meet adequate levels of carotene
from their diets.
Enquiry on the processing practices adopted for cooking p-carotene
rich vegetables revealed that sauteing, boiling / stewing and pressure
cooking were the commonly employed methods. The use of pressure
cooker was however more common among urban families. Similarly the
use of modern gadget microwave was also found only among very
fewurban households.
Following the standardised procedures of cooking, the ten p-
carotene rich vegetables were processed and subjected to bioavailability
study.
Bioavailability analysis of selected p-carotene rich foods
highlighted that processing treatments of vegetables namely sauteing,
boiling and stewing released more bioavailable form of p-carotene. At the
same time processing techniques in which a high temperature was
employed as in the case of pressure cooking and microwave cooking, the
bioavailability of ~-carotene was found to be lower than the same
unprocessed vegetables.
With respect to all green leafy vegetables studied, the
bioavailability percentage was .maxirnum when cooked by sauteing.
Processing influence on the remaining vegetables revealed that sauteing,
boiling and stewing were better methods for enhanced bioavailability or
~-carotel1e compared to their other processed forms and raw samples
experimented in this study. Boiling was observed for carrots, pumpkin
and green amaranth. Similarly for yam both sauteing and stewing was
found to be the ideal methods, while for tomato stewing was the best
method since these treatments improved ~-carotene bioavailability; even
for cluster beans. sauteing was recorded as the best cooking practice.
To bring the observations to a nut shell, it was concluded that certain
processing treatments such as sauteing, stewing and boiling were found to
be positively influencing ~-carotene bioavailability from vegetables and
fruits. Sauteing was proved to be an outstanding and superior processing
method enhancing ~-carotene bioavailability, followed by boiling and
stewing. Study also highlighted the variations in bioavailability status or
~-carotene from different plant foods. It was observed that the percentage
bioavailability of ~-carotene from fruits like tomato and pumpkin was
high followed by carrot, yam and cluster beans. Green leafy vegetables
eventhough labeled as the richest source of ~-carotene, bioavailability of
this nutrient was comparatively low.
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