Nutritional value and acceptability of lactic acid …...2016/03/15 · Nutritional value and...
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Nutritional value and acceptability of lactic acid fermented sweetpotato leaves utilized as vegetables The Markets, Processing, and Utilization Community of Practice Meeting Dar Es Salam, Tanzania 14-16 th March 2016
Transcript of Nutritional value and acceptability of lactic acid …...2016/03/15 · Nutritional value and...
Nutritional value and acceptability of lactic acid fermented sweetpotato leaves utilized
as vegetables
The Markets, Processing, and Utilization Community of Practice Meeting
Dar Es Salam, Tanzania14-16th March 2016
Authors
George Ooko Abong’*, Mercy Chepkoech, Grace Oguya
*Dept. Food Science, Nutrition and Technology, University of Nairobi, Box 29053, Nairobi, Kenya.
[email protected];+254700073386
Introduction • Sweetpotatoes play important food security role.
• Mainly roots are utilized in East Africa while leavesand vines utilized as animal feed.
• Leaves are highly perishable and only acceptableto a few users in Kenya unlike other countrieswhere they are generally consumed.
• Sweetpotato leaves are good sources of vitaminsA and C, protein, iron and zinc.
Introduction • Recent introduction and promotion of
orange-fleshed sweetpotatoes in EA, Kenyaincluded.
• Increased utilization of leaves in addition toroots would enhance the nutritionalcontribution of the crop to the human dietsignificantly-complete!!!!
• Especially in terms of increased vitamin Cand protein intake.
Introduction • Traditional preparation methods can be in order, but
other value addition methods may be necessary.
• Lactic acid fermentation known to enhance nutrientavailability provides an alternative process ofproducing a value added product from the leaves.
• Nutritional value and acceptability of lactic acidfermented sp leaves in Kenyan context remainsunknown.
• Preliminary partial results of trials from TransmaraEast presented.
Methodology• Current presentation part of ongoing research-
only a section is presented.
• Three varieties commonly grown in Transmara ,Narok County harvested from farmers-purpleleaves, purple vines and green leaves.
• Leaves analysed for protein, moisture, oxalates,vitamin A & C-
• Analysis on raw and cooked (traditional boiling)-sensory evaluation carried out.
• Lactic acid fermentation, minerals on-going
Results-MC• High moisture foods as other vegetables; sig differ
with variety
76.0280.58
74.1178.94
84.66 87.71
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
80.00
90.00
100.00
Raw Cooked Raw Cooked Raw Cooked
Green leaves Purple leaves Purple vines
%M
C
Results-Beta carotene• Sig. (p<0.05) high in purple vines; retention 53-69%
2098.88
3208.59
2199.34
3194.582742.42
5141.65
0.00
1000.00
2000.00
3000.00
4000.00
5000.00
6000.00
Cooked Raw Cooked Raw Cooked Raw
Green leaves Purple leaves Purple vines
bet
a ca
rote
ne
(µg
/10
0g)
Results-Vitamin C• No sig. with variety; high vit C; retention of 32 and
42%
159.11
482.91
188.46
446.25
180.10
552.99
0.00
100.00
200.00
300.00
400.00
500.00
600.00
700.00
Cooked Raw Cooked Raw Cooked Raw
Green leaves Purple leaves Purple vines
vita
min
C (
mg
/10
0g)
Results-Protein• No sig. difference with variety or reduction on
boiling
19.89 20.34 19.8222.86
20.5822.60
0.00
5.00
10.00
15.00
20.00
25.00
30.00
Cooked Raw Cooked Raw Cooked Raw
Green leaves Purple leaves Purple vines
pro
tein
co
nte
nt
(%)
Axis Title
Results-Protein• High fibre; some reduction??
11.00
12.48 12.23 12.7611.35
13.11
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
16.00
Cooked Raw Cooked Raw Cooked Raw
Green leaves Purple leaves Purple vines
Cru
de
fib
re (
%)
Results-Oxalates• No sig difference with variety; Sig. reduction in
purple varieties
868.62980.29
728.30
924.32
731.22
1265.17
0.00
200.00
400.00
600.00
800.00
1000.00
1200.00
1400.00
1600.00
Cooked Raw Cooked Raw Cooked Raw
Green leaves Purple leaves Purple vines
oxa
late
s (m
g/1
00
g)
Sensory-Taste
• Liked moderately
0
10
20
30
40
50
60
70
like moderately like very much dislike slightly Neither
Perc
ent
resp
on
den
ts
Purple vine Purple leaves Green leaves
Sensory-Flavor• Liked moderately
0
10
20
30
40
50
60
70
80
90
likemoderately
like very much dislike slightly neither likenor dislike
Dislike verymuch
Perc
ent
resp
on
den
ts
Purple vine Purple leaves Green leaves
Sensory-Appearance• Liked moderately
0
10
20
30
40
50
60
70
80
like moderately like very much dislike slightly dislike very much
Perc
et r
esp
on
den
ts
Purple vine Purple leaves Green leaves
Sensory-Texture• Liked moderately
0
10
20
30
40
50
60
70
80
90
like moderately like very much dislike moderately neither like nordislike
per
cen
t re
spo
nd
ents
Purple vine Purple leaves Green leaves
Sensory-overall acceptability• All acceptable-liked moderately
0
10
20
30
40
50
60
70
Purple vine Purple leaves Green leaves
Perc
ent
resp
on
den
ts
like moderately like very much dislike slightly
Conclusions and way forward• Sweetpotato leaves have high levels of vit. A&C
and good amount of protein.
• Leaves acceptable as boiled vegetables.
• Normal boiling reduces vitamins and oxalates sign,
• Oxalate reduction by fermentation to beestablished.
• Mineral evaluation and lactic acid fermentationongoing.
Acknowledgements • UON
• SASHA
THANK YOU
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