Mwangi Anthony Kimani - Department of Food Science, Nutrition

BETA-CAROTENE RETENTION IN OVEN AND SUN DRIED CARROTS
BY
MW ANGI ANTONY KIMANI
A90/0267/2009
Project Report submitted to the department of Food Science, Nutrition and Technology
in partial fulfillment for the award of Bachelor of Science in Foods, Nutrition and Dietetics .
..
SUPERVISORS:
DR.ALICE MWANGI
MS JANE NJENGA
~.j
.
~\,
,
DECLARATION:
I declare that this is my original work and that it has not been presented in whole or in part for
the award of any other degree in any university.
Investigator; Antony Kimani
Supervisor 1; DR Alice Mwangi
Supervisor 2; JANE NJENGA
Signature-~
--_d.( / ~ I 3
TABLE OF CONTENTS
ABSTRACT
iv
CHAPTER ONE
1
1.1 BACKGROUND INFORMATION
1
1.2 PROBLEM STATEMENT
2
1.3 STUDY JUSTIFICATION
:
1.4 AIM OF THE STUDy
2
2
To contribute to the reduction of the incidences of vitamin A deficiency
2
1.5 STUDY PURPOSE
2
1.6 MAIN OBJECTIVE
2
1.7 SUB-OBJECTIVE
2
CHAPTER 2
3
2.0 LITERATURE REVIEW
3
CARROTS
3
2.1 HEALTH BENEFITS ASSOCIATED WITH EATING CARROTS
4
2.11 Antioxidants in carrots
4
2.22 Cardiovascular benefits
4
2.23 Visual health
4
2.24 Anti-cancer benefits
5
2.3 BETA CAROTENE
5
2.4 Characteristics of Beta-Carotene
6
2.5 Vitamin A deficiency
7
2.6 Amount of beta-carotene in fresh carrots
8
2.7 GAPS TO BE FILLED BY THIS PROJECT
8
CHAPTER 3
9
3.1 STUDY DESIGN AND METHODOLOGy
9
3.11 Methodology
9
ii
DISCUSSION
14
CONCLUSION
16
RECOMMENDATION
16
REFERENCES
17
APPENDICES
18
iii
ABSTRACT
Despite major interventions and program to deal with the cases of vitamin A deficiencies, the
rates remain high, at 14.7% in children and 9% in women with the conditions related to the same
affecting lives of so many people. This is because the dietary sources of beta-carotene, (a
precursor for vitamin A) like carrots, dark green vegetables and fruits are not evenly distributed
throughout the country and are seasonal. Again, considering that this source is perishable it is
hard to reach people countrywide in good condition because of poor infrastructure and storage
facilities. Methods of preserving carrots like refrigeration and freezing may also be expensive
especiallyto people of low economic status. Animal sources of vitamin A are also expensive.
The project therefore was aiming at contributing to the reduction of vitamin A deficiency in
Kenya. This was to be achieved through reducing carrots water activity and increasing carrots'
shelf life and this was to ensure that every Kenyan could access this precious source of vitamin
A without incurring other storage costs and this was to consequently reduce the conditions of
vitamin A deficiency in Kenya like night blindness and xerophthalmia among others.
The objective of this project was to assess the retention of beta carotene in dried carrots. Carrots
were dried using three different methods and beta carotene retained from each method
determined. To do this carrots sample were obtained from the market, washed, grated and the
initial beta-carotene determined. Then another sample was taken, and part of this sample was sun
dried and the other part was dried in an oven to a moisture content of 10%.
Data analysis
Each drying method had 5 samples whose results were averaged to get the mean of the beta
carotene retained. Then these means were compared using ANOVA tables to establish the
variability among the three methods.
iv
CHAPTER ONE
1.1 BACKGROUND INFORMATION
B-Carotene is a strongly colored red- orange pigment abundant in plants and fruits like dark
green vegetables like spinach and fruits like mangoes. It gives yellow and orange fruits and
vegetables their rich hues. Plant carotenoids are the primary dietary source of pro vitamin A
worldwide,
with
~-carotene
as
the
best
known
as
pro
vitamin
A
carotenoid.
(http://en.wikipedia.org/wikilBeta-Carotene
Beta-carotene is converted to vitamin A (retinol) by the body. Vitamin A is needed for good
vision and eye health, for a strong immune system, and for healthy skin and mucus membranes.
While large amounts of vitamin A in supplement form can be toxic, the body will convert only as
much vitamin A from beta-carotene as it needs. That means beta-carotene is considered a safe
source of vitamin A. Like all other carotenoids, beta-carotene is an antioxidant. It protects the
body from damaging molecules called free radicals. Free radicals cause damage to cells through
a process known as oxidation. Over time, this damage can lead to a number of chronic illnesses.
There is good evidence that getting more antioxidants through your diet helps boost your
immune system, protect against free radicals, and may lower your risk of two types of chronic
illness -- heart disease and cancer.
(http://www.whfoods.com/genpage.
php ?tname=nutrient&dbid=
125)
Beta -carotene is important to human beings as it helps in the synthesis of vitamin A. Vitamin A
is needed
for new
cell
growth,
healthy
skin,
hair,
and tissues,
light.(http://www.nutristrategy.comlnutritionlvitamina.htm).vitamin
A
and vision
IS
an
in dim
essential
micronutrient for the immune system and plays an important role in maintaining the epithelial
tissue in the body. Severe vitamin A deficiency (VAD) can cause eye damage. VAD also
increases severity of infections such as measles and diarrheal diseases in children and slow
recovery from illness. Most of the time VAD is corrected with vitamin A supplements. (KDHS
2008-09 page154)
1
1.2 PROBLEM STATEMENT
The prevalence of vitamin A deficiency is high despite the many nutrition interventions.
People of low economic status may not afford to buy refrigerators to store carrots
Supplements of vitamin A can sometimes be toxic to the body.
Post-harvest loss or spoilage of carrots
Animal sources of vitamin A are expensive
1.3 STUDY JUSTIFICATION
Through drying carrots, the keeping qualities of carrots can be enhanced and les cost will be
incurred in storing carrots
1.4 AIM OF THE STUDY
To contribute to the reduction of the incidences of vitamin A deficiency
1.5 STUDY PURPOSE
The purpose was to assess whether drying of carrots has potential for retention of beta-carotene
as a way of reducing wastage and providing carrots throughout the year.
1.6 MAIN OBJECTIVE
To determine the retention of beta-carotene in oven and sun dried carrots
1.7 SUB-OBJECTIVE
To determine the amount of beta-carotene retained upon drying of carrots
To evaluate different methods of drying carrots.
2
CHAPTER 2
2.0 LITERATURE REVIEW
CARROTS
The carrot is a root vegetable, usually orange in color, though purple, red, white, and yellow
varieties exist. It has a crisp texture when fresh. The most commonly eaten part of a carrot is a
taproot, although the greens are edible as well. It is a domesticated form of the wild carrot
Daucus carota, native to Europe and southwestern Asia. The domestic carrot has been selectively
bred for its greatly enlarged and more palatable, less woody-textured edible taproot.
Carrots belong to the Umbelliferae family, named after the umbrella-like flower clusters that
plants in this family produce. As such, carrots are related to parsnips, fennel, parsley, anise,
caraway, cumin and dill. Carrots can be as small as two inches or as long as three feet, ranging in
diameter from one-half of an inch to over two inches. Carrot roots have a crunchy texture and a
sweet and minty aromatic taste, while the greens are fresh tasting and slightly bitter. While we
usually associate carrots with the color orange, carrots can actually be found in a host of other
colors including white, yellow, red, or purple. In fact, purple, yellow and red carrots were the
only color varieties of carrots to be cultivated before the 15th or 16th century.(source;
http://en.wikipedia.org/wiki/Carrot)
TABLE 1
Carrot varieties
Carrots color
variety
use
Orange Carrots
Scarlet Nantes
especially valued for its sweetness
Camden
often raised for processing
Danvers
often raised for processing
Purples Carrots
Indigo, Maroon, Purple Dragon,
Cosmic Purple, Purple Haze
Yellow Carrots
Sunlite, Solar Yellow,
Yellowstone
White Carrots
Creme De Lite, White Satin
3
2.1 HEALTHBENEFITS ASSOCIATED WITH EATING CARROTS
The active form of vitamin A participates in three main functions: visual perception, cellular
differentiation and the immune system. The classical function of vitamin A is the rod and cones
of the retina for dim light and day light vision (source: present knowledge in nutrition, page 131)
According to The World's Healthiest food book by George Meteljan the following benefits can
be gotten from carrots
2.11Antioxidants
in carrots
All varieties of carrots contain valuable amounts of antioxidant nutrients. Included here are
traditional antioxidants like vitamin C, as well as phytonutrient antioxidants like beta-carotene.
The list of carrot phytonutrient antioxidants is by no means limited to beta-carotene, however.
This list includes: Carotenoids (alpha-carotene, beta-carotene, lutein alpha-carotene, betacarotene lutein Hydroxycinnamic acids (caffeic acid coumaric acid ferulic acid) and
Anthocyanin (Maldivians) Different varieties of carrots contain differing amounts of these
antioxidant phytonutrients. Red and purple carrots, for example, are best known for the rich
anthocyanin content. Oranges are particularly outstanding in terms of beta-carotene, which
accounts for 65% of their total carotenoid content. In yellow carrots, 50% of the total carotenoids
come from lutein.
2.22 Cardiovascular
benefits
The presence of high amounts of antioxidants in carrots mostly help to protect the arteries from
free radical attack since they carry highly oxygenated blood. These antioxidants includes the
polyacetylenes like fa1carinol and falcarindol which have anti-inflammatory properties and antiaggregatory properties that help prevent excessive clumping together of red blood cells.
2.23 Visual health
Bata carotene in carrots helps in the synthesis of rhodopsin, which helps human beings and
animals to see in dim light.
4
2.24 Anti-cancer
benefits
The anti-cancer benefits of carrot have been best researched in the area of colon cancer. Some of
this research has involved actual intake of carrot juice by human participants, and other research
has involved the study of human cancer cells types in the lab. While much more research is
needed in this area, the study results to date have been encouraging. Labs studies have shown the
ability of carrot extracts to inhibit the grown of colon cancer cells, and the polyacetylenes found
in carrot (especially falcarinol) have been specifically linked to this inhibitory effect. In studies
of carrot juice intake, small but significant effects on colon cell health have been shown for
participants
who
consumed
about
1.5
cups
of
fresh
http://www.whfoods.comlgenpage.php?tname=foodspice&dbid=21
carrot
juice
per
day.(source:
)
2.3 BETA CAROTENE
Beta-carotene is a type of pigment found in plants, especially carrots and colorful vegetables.
The name beta-carotene is derived from the Latin name for carrot. It gives yellow and orange
fruits and vegetables their rich hues. Beta-carotene is also used as a coloring agent for foods such
as margarine.
Beta-carotene is converted to vitamin A (retinol) by the body. Vitamin A is needed for good
vision and eye health, for a strong immune system, and for healthy skin and mucus membranes.
While large amounts of vitamin A in supplement form can be toxic, the body will convert only as
much vitamin A from beta-carotene
as it needs. That means beta-carotene
is considered a safe
source of vitamin A. However, too much beta-carotene can be dangerous for people who smoke.
(Getting high amounts of either vitamin A or beta-carotene
through your diet -- not from
supplements -- is safe.)
Like all other carotenoids, beta-carotene is an antioxidant. It protects the body from damaging
molecules called free radicals. Free radicals cause damage to cells through a process known as
oxidation. Over time, this damage can lead to a number of chronic illnesses. There is good
evidence that getting more antioxidants
through your diet helps boost your immune system,
protect against free radicals, and may lower your risk of two types of chronic illness -- heart
5
disease and cancer. However, the issue is a little murkier when it comes to taking antioxidant
supplements.(Source :
http://www.umm.edulaltmed/articleslbeta-carotene-
000286.htm#ixzz2CxKDx903 )
2.4 Characteristics of Beta-Carotene
Like all carotenoids, beta-carotene is the most common form of carotene.
Fat soluble. In a mixed diet, 3-5 grams of fat is enough to ensure its absorption. Carotenoids
suspended in oil are more efficiently absorbed than those in water or food.
Manufactured by plants. In plants, beta-carotene absorbs light and energy from singlet oxygen an unstable form of oxygen - and transfers both energies to chlorophyll for photosynthesis.
It
also acts as a pesticide.
Present in the all-trans configuration in raw fruits and vegetables
Converted to the cis- configuration
during cooking. Cis- isomers are shorter in length and are
less susceptible to "binding." They are more stable and are more bioavailable.
Released from the food matrix by: chewing, stomach action, and digestive enzymes. The vitamin
A activity of beta-carotene
in foods is half that of retinol (pre-formed
vitamin A). Biologic
Activities of Beta-Carotene
Beta-carotene is converted to Vitamin A (retinal) in the small intestines of mammals by beta-,
carotene 15, 15 mono oxygenase (an enzyme). In times of plenty, retinal is stored in the liver. It is
synthesized into active vitamin A in times of need.
It quenches singlet oxygen. It also reacts with any radical species present in a biological system.
As a powerful antioxidant, it breaks down and converts harmful products to inert substances.
It prevents the oxidation of fat by breaking down the chain-reaction.
6
It facilitates communication between cells by enhancing the expression of a gene that codes for
connexin proteins. Connexin proteins form pores or gap junctions in cell membranes, allowing
cells to communicate through the exchange of small molecules.
It improves immune function by protecting phagocyte cells (white blood cells that protects the
body by ingesting harmful bodies, bacteria, dead/dying cells); enhancing the response of T & B
cells (immune response cells); by stimulating the effects of T-cell functions, macrophage, and
natural killer cell capacities, and by increasing the production of interleukins. Interleukins are
signalingmolecules on white blood cells. They mediate communication between cells.
It helps maintain night vision. As vitamin A, beta-carotene maintains the cornea and participates
in the conversion of light energy into nerve impulses at the retina. The cells of the retina contain
rhodopsin, a pigment molecule. As rhodopsin absorbs light, retinal changes which triggers a
nerve impulse that carries information to the brain.
It protects against sunburn by: quenching radical oxygen species and interfering with several
signalingpathways that result in UV-B exposure.
2.5 Vitamin A deficiency
Not everyone is equally vulnerable to vitamin A deficiency, which depends on a senes of
geographical and epidemiological factors. Among the ecological issues are poverty and
unemployment, low birth weight, poor sanitation and parasitism. Young people aged 6 months to
6 years are at greatest risk of ocular and infectious mortality associated with vitamin A
deficiency, and the risk of hypovitaminosis A is greater if breastfeeding has been absent or
limited. (Source: present knowledge in nutrition, page 132)
Night blindness, a condition associated with an impairment of the vision in dim light is caused
by lack of dietary sources of vitamin A. (source: vitamins in human health and diseases, page
148)
7
2.6 Amount of beta-carotene in fresh carrots
Carrots are a rich source of beta-carotene, as each 100 g serving of raw carrots provides about
8,285 mcg of this nutrient. According MayoClinic.com, you need just 1,800 mcg daily to
maintain healthy levels of vitamin A, so 100 g of carrots provides more than enough betacarotene to do so. livingstrong.com
2.7 GAPS TO BE FILLED BY THIS PROJECT
Little information is documented about the beta-carotene retention in dried carrots and this
formed the backbone ofthis project.
Despite the fact that carrots can have a shelf life of 2-3 weeks in a refrigerator and 12-18 months
in a freezer, people of low economic status may not afford these freezers and refrigerators.
Drying carrots was meant ensure that people far away from where carrots are cultivated get
access to carrots in good form unlike the case where carrots go bad during transport because of
high moisture content. This was to help reduce cases of vitamin A deficiency.
High cost of storage could be reduced, wastage due to high moisture could be reduced,
Seasonality and uneven distribution of carrots.
8
CHAPTER 3
3.1 STUDY DESIGN AND METHODOLOGY
3.11Methodology
Fresh carrots were randomly sampled from the market
~
Washed with abuldant running water
Blanched
Grr1
ed
Sampled
~
Samples homogenized
t
4 samples made
1" sampj" is sundried
2"' is driedfO
3" is
a sun driejr
OVI dried
4th
is fresh
1
5 sub-samples
5sub samples
5 sub-samples
5 sub-samples
Analysis of the 3 means using ANOVA table
3. 2 Study location; Collage of Agriculture and Veterinary Sciences
3.3 Tools and equipment for data collection
Sun dryer, oven dryer, volumetric flasks, desiccators, round bottomed flask, spectrophotometer,
chromatography column, methanol, sodium sulphate, aluminium oxide, silica gel, petroleum
ether, ethanol,
9
3.4 data collection procedures
2 kilograms of carrots were bought from Kangemi market from different vendors
The sample was washed with clean running water
Sample was blanched by putting them in boiling water for 6 minutes
The sample was then be grated and dried to a moisture content of 10% using different methods
Methods of drying carrots
3.5 Sun drying
About 500 grams of grated carrots were sun-dried to a moisture level of 10% in the sun
3.6 Using a sun dryer
About 500 grams of fresh carrots were dried in a sun dryer to a moisture content of 10% for 4
days.
3.7 Air -oven drying
About 10 grams of grated carrots were weighed in a dish
The dish and its content were put in an air oven maintained at 65 and 105°c
The dried sample was cooled in a desiccators and weighed
Then the moisture content was determined
3.8 Beta carotene determination
Methodology
About 2 grams of the fresh grated carrots were taken
The color was extracted using mortar and pestle with small portions of acetone until the residual
became colorless
Extracts were then put in a 100 mls volumetric flask
25mls of the extract were taken and put into a 50mls round bottomed flask
Evaporated to dryness in a rotary evaporator at about 60 °c
To the evaporated sample, 1 ml of petroleum spirit was added so as to dissolve the beta carotene.
Beta carotene was eluted through a packed column
The elute was received in a 25 mls volumetric flask
The absorbance was then be read at 450 nm
•
Beta-carotene was calculated from the beta carotene standard curve
The procedure was repeated with the oven dried carrot samples and sun dried carrot sample
10
3.9 data quality control
The data was accurately collected and analysed from the 5 sub-samples of each sample and
recorded.
3.91 data handling and analysis
Table 2-fresh sample
Sub-samples
Concentration in milligramsll OOgrams
absorbance
1
306.75
0.409
2
308.25
0.432
3
324.00
0.419
4
306.75
0.402
5
302.25
0.401
Mean of concentration
309.45
Discussion
From the above table the mean of beta-carotene is 309.45mg/l00grams
Table 3-oven dried sample at 105°c
Sub-sample
Concentration in milligramsll OOgrams
absorbance
1
90.00
0.120
2
88.50
0.118
3
90.75
0.121
4
90.00
0.120
5
90.00
0.120
Mean of concentration
89.85
Discussion
The amount of beta-carotene retained after oven drying carrots at 105°c is 89.5mgll00grams
which represent 29.04% retention.
11
Table 4-oven dried sample at 65°c
Sub-sample
Concentration in milligrams/1 OOgrams
absorbance
1
120.00
0.160
2
118.50
0.158
3
120.75
0.161
4
122.25
0.163
5
120.00
0.160
Mean of concentration
120.30
Discussion
The amount of beta-carotene retained when 100grams of carrots are dried in an oven dryer at
65°c is 120.30mg which represent a 38.88%.
Table 5-sundried sample
Sub-sample
Concentration in
absorbance
milligrams/l00grams
1
127.50
0.170
2
127.50
0.170
3
128.25
0.171
4
129.00
0.172
5
126.25
0.169
Mean of concentration
127.80
12
Discussion
100grams of carrots dried in the sun retained most beta carotene (127.80mg).this
41.29 % retention.
Variability determination
ANOVA
Sl(oven at 105uc)
S2(oven at 65°c)
S3(sundried)
90.00
120.00
127.50
88.50
118.50
127.50
90.00
120.75
128.25
90.00
122.25
129.00
90.00
120.00
126.75
Sum=449.25
601.50
639.00
Formula
Summation of square =sumX2 - (sum x) 2/n
Where n is the number of replication
Sum ofx2=194267.25
CF=190350.33
SS total=194267.25-190350.33=4116.9
SS TOTAL=4116.9
SS treatment=Ti/ri -CF
194389.8-190350.33=4039.4
SST=4039.4
SS error =SS total -ss treatment
4116.9-4039.4=77.5
SS ERROR =77.5
13
is equivalent to
Sources of variation
Df
SS
MS
Vr
Treatment
t-1= 3-1=2
4039.4
2019.7
312.7
Error
n-t= lS-3=12
77.S
6.S
Total
n-1= lS-1=14
4116.9
DISCUSSION
Calculated value is 312.7
F VALUE AT S% CONFIDENCE INTERVAL, 2 DF DOWNARDS AND 12 DF ACROSS
THE F-TABLES WAS 39.41.
F (2, 12, O.OS) =39.41
IF THE CALCULATED VALUE IS GREATER THAN THE TABLE VALUE, THE NULL
HYPOTHESIS IS REJECTED AND THE ALTERNATIVE ADOPTED.
Null hypothesis was; mean 1=mean2=mean3, meaning there was no differences between drying
methods 1, 2 and 3.
Alternative hypothesis was; mean1 is not=mean2 and not= mean3, meaning that, there was
VARIAnONS (VARIABLITY) between the 3 methods.
In this project the calculated value (312.7) which was by far greater than the table value of
(39.41). This meant rejecting the null hypothesis and accepting the alternative hypothesis.
INFERENCE
THERE WAS VARIABILITY BETWEEN THE THREE METHODS (drying at 10Soc, drying at
6Socand sun drying) USED IN DRYING CARROTS.
14
Comparison of the four samples
120.00% .,------------------------100.00%
80.00%
+----------------------r---:r--
100%
+--------------------
60.00% +-------------------40.00% t----::;-a;~r---r===2--.;;;;;;;;;,;jjI--20.00%
0.00%
oven dryer at 105 oven dryer at 65
degrees
degrees
solar dryer
fresh carrots
Drying carrots using the three methods has shown a good potential for retention of beta carotene.
The highest level of retention was noticed in the sun-dried carrots. This was probably because
sun temperatures are not as high as the air oven drying at 65 degrees and 105 degrees, therefore
highest retention.
15
CONCLUSION
There was substantial amount of beta carotene retained after drying carrots. The amount is
especially high
III
sundried
carrots.
The
amount
of
beta-carotene
retained
III
milligramsllOOgramsis over and above the Recommended Dietary Allowance (RDA) of
4.5milligrams per day. Therefore dried carrots can be used to contribute to the reduction of
vitaminA deficiency in Kenya.
RECOMMENDATION
The project recommends drying carrots in the sun because the method is cheap and retains
highest amounts of beta-carotene as compared to other methods. It recommends blanching of
carrots before drying, to retain color. To pack the dried carrots in sachets of 20 grams (20grams
of dried carrots will meet the RDA of a person)
16
REFERENCES
•
Contemporary nutrition by Gardon M. Wardlow, page 283
•
Food chemistry by Springer Berlin Heidelberg, page 305
•
Ngare DK, Muttunga IN, Njonge E, Year 2000 ,Vitamin A deficiency in pre-school
children in Kenya, http://www.ncbi.nlm.nih.gov/pubmedl12862065
(accessed on 13th of
feb2013)
•
Kenya Demographic and Health survey 2008-09
•
Robert Russell, 2001, Present Knowledge in Nutrition page 184 : 132
•
The Kenya National Technical Guidelines for Micronutrient Deficiency Control August
2008, page 154)
17
APPENDICES
BETA-CAROTENE
STANDARD CURVE
Concentration in ug/ml
absorbance
0.4
0.120
0.8
0.240
1.2
0.350
1.6
0.480
2.0
0.580
2.4
0.720
18