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Process optimization for drying of drumstick leaves Publication History Received: 03 February 2016 Accepted: 27 February 2016 Published: 1 March 2016 Citation Kannan K, Thahaaseen A. Process optimization for drying of drumstick leaves. Indian Journal of Science, 2016, 23(79), 275-288
Indian Journal of Science Method The International Journal for Science ISSN 2319 – 7730 EISSN 2319 – 7749 © 2016 Discovery Publication. All Rights Reserved
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PROCESS OPTIMIZATION FOR DRYING OF DRUMSTICK LEAVES
K.KANNAN1*, A.THAHAASEEN2
kk@kongu.ac.in
ABSTRACT
There are many varieties of green leafy vegetables which are though rich in
micronutrients, but are usually discarded or are not used for human consumption. One such
leaf, a rich source of micronutrients but still under exploited is Moringa leaf (Moringa
oleifera). Dried Moringa leaves can be stored during off seasons however drying causes
degradation of colour characteristics which reduces its marketable value. In present
investigation, efforts were made to analyze the effect of different pre treatments and drying
methods such as sun, shade and hot air oven drying at different temperatures (50, 60, 70˚C) on
the nutritive value of the selected leaf for Moringa leaves drying. The results revealed that
Moringa leaves pre-treated with 0.1% sodium bicarbonate and dried in shade drying gave
better results in drying characteristics and nutritional analysis such as carbohydrates - 33.86g,
fibre - 8.18g , protein - 27.40g , vitamin-C – 13.21mg, chlorophyll content-3.1 mg
respectively. Similarly in oven drying at 50˚c Moringa leaves treated with Na2Co3 shows the
best result. The nutritional content in oven dried Moringa is iron – 15.2mg, carbohydrates –
28.6g, fibre - 6.5g , protein - 24.40g , vitamin-C – 10.81mg, chlorophyll content-2.4 mg
respectively. On the basis of obtained results it could be concluded that shade drying treated
with Na2Co3 is superior to that of sun and hot air oven drying in terms of nutritional content.
Key words: Moringa oleifera, dehydration, sun drying, shade drying, oven drying,
biochemical analysis
1*. Assistant Professor, Department Of Food Technology
2. M.Tech, Department Of Food Technology
Kongu Engineering College
Perundurai, Erode.
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1. INTRODUCTION
Drumstick leaves (Moringa oleifera) is one of them, which is available at no cost and
is very rich in all the micronutrients. M. oleifera, commonly referred to simply as "Moringa",
is the most widely cultivated species of the genus Moringa, which is the only genus in the
family Moringaceae. It is an exceptionally nutritious vegetable tree with a variety of potential
uses. The tree itself is rather slender, with drooping branches that grow to approximately 10 m
in height. The "Moringa" tree is grown mainly in semi - arid, tropical, and subtropical areas,
while it grows best in dry sandy soil, it tolerates poor soil, including coastal areas. It is a fast -
growing, drought resistant tree that is native to the southern foothills of the Himalayas in north
western India. The immature green pods called “drumsticks” are probably the most valued and
widely used part of the tree. They are commonly consumed in India and are generally prepared
in a similar fashion to green beans and have a slight asparagus taste. The seeds are sometimes
removed from more mature pods and eaten like peas or roasted like nuts. The flowers are
edible when cooked, and are said to taste like mushrooms. The leaves are highly nutritious,
being a significant source of beta carotene, Vitamin C, protein, iron, and potassium. The
leaves are cooked and used like spinach. In addition to being used fresh as a substitute for
spinach, its leaves are commonly dried and crushed into a powder, and used in soups and
sauces. Murungakai, as it is locally known in Tamil Nadu and Kerala, is used in Siddha
medicine. Its leaves are full of medicinal properties (Pandhre GR, Satwase AN.,(2011).
Drumstick leaves are commonly consumed in India and are generally prepared in a
similar fashion to green beans and have a slight asparagus taste. The seeds are sometimes
removed from more mature pods and eaten like peas or roasted like nuts. The flowers are
edible when cooked, and are said to taste like mushrooms. The leaves are highly nutritious,
being a significant source of beta - carotene, Vitamin C, protein, iron, and potassium. It is
commonly said that Moringa leaves contain more Vitamin A than carrots, more calcium than
milk, more iron than spinach, more Vitamin C than oranges, and more potassium than
bananas,” and that the protein quality of Moringa leaves rivals that of milk and eggs. The
leaves are cooked and used like spinach. In addition to being used fresh as a substitute for
spinach, its leaves are commonly dried and crushed into a powder, and used in soups and
sauces. Its leaves are full of medicinal properties.
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Incorporation of dried leaves in food products can have good sensory
acceptance. Lalitha and Sathya (2003) incorporated curry leaves, and coriander leaves powder
in commonly used instant mixes such as dhal powder, bajji mix and vadai mix and reported
that all products were equally acceptable. Singh and Awasthi (2003) investigate the effect of
powder made from kachnar, colocasia and curry leaves incorporated food products and found
that it is significantly acceptable. The food products prepared using powders of amaranth,
curry leaves, gogu and mint were rated as highly acceptable for all the sensory attributes and
were scored from good to excellent on five point scale Lakshmi and Vimala (2000). The effect
of blanching prior to dehydration in cross air flow drier was studied in seven leafy vegetables
viz., dhantu, khirkhire, honagone, chakota, palak, kachiand fenugreek showed the highest
retention of chlorophyll (Premavalli et al., 2001). Blanching of amaranth in hot water (95 ±
3°C) for one minute followed by cooling in running tap water and dipping in 0.5 per cent
solution of potassium meta bisulphite for one minute prior to drying in cabinet drier showed
higher retention of chlorophyll, ß-carotene and lowered non-enzymatic browning (Negi and
Roy, 2001)
Drying is almost certainly the oldest method that humans have practiced to preserve
food for future use. Drying foods in sunlight reduced the weight and volume of the foods so
that they could be more easily stored and transported by our ancestors. Drying occurs by
effecting vaporization of the liquid by supplying heat to the wet feedstock. As noted earlier,
heat may be supplied by convection (direct dryers), by conduction (contact or indirect dryers),
radiation or volumetrically by placing the wet material in a microwave or radio frequency
electromagnetic field (Arun S. Mujumdar and Sakamon Devahastin 2001). Over 85 percent of
industrial dryers are of the convective type with hot air or direct combustion gases as the
drying medium. Over 99 percent of the applications involve removal of water.
The major challenge that is being faced in the moringa leaves production is its lower shelf life.
Thus the objective of our project is
To pre-treat the sample with sodium chloride and sodium bicarbonate.
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To dehydrate the leaves with various drying methods (sun, shade, hot air oven) and
temperature (50˚C, 60˚C, 70˚C).
To estimate Proximate analysis of the dehydrated drumstick leaves
To determine the drying characteristics and obtain a solution by comparative study.
2. MATERIALS AND METHODS:
The drumstick leaves, one of green leafy vegetable was obtained from local vegetable
market. These leaves were easily available across every corner even in remote areas .The
leaves were also grown in many house hold especially in villages.
Selection of drumstick leaves
↓
Cutting
↓
Washing
↓
Pretreatment (NaCl & Na2Co3)
↓
Drying using sun, shade and Hot air oven (50°, 60° and 70°C)
↓
Grinding
↓
Optimization
Fig.1 Methodology
Independent variables are type of drying (sun, shade, hot air oven drying) and
temperature of hot air oven (50˚C, 60˚C, 70˚C). Dependent variables are moisture content, ash,
crude fibre, carbohydrate, protein, chlorophyll, and vitamin-C.
The drumstick leaves were pretreated to retain the colour. The drumstick leaves
were, washed and then pretreatment was done with sodium chloride (2% NaCl) and sodium
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bicarbonate (0.1% Na2Co3). Then the water is drained and drying is done. The leaves are
spread on a large tray and different types of drying are carried out (sun, shade, hot air oven
drying).
DRYING
The techniques used for dehydration were (i) Sun drying; (ii) Shade drying and (iii) Hot air
oven drying
Sun drying:
The leaves were placed on large tray. The tray were placed in a direct sunlight on a
roof away from dust to assure even drying. During drying the temperature of the leaves were
noted. The temperature is about 26˚c.
Shade drying:
In shade drying, the leaves were spread on large tray but instead of keeping them on
the roofs the leaves were kept in the room only. The room selected for shadow drying was
well ventilated. Natural current of air was used for shadow drying the leaves.
Hot air oven drying:
The leaves were spread on the trays and kept in hot air oven ( Hasthas Hot air oven).
The leaves were dried in the hot air oven by forced air technique. The temperature was
maintained at 50°C, 60°C, 70°C and the leaves were dried. The dried leaf samples were then
analyzed for (i) Proximate composition (Protein, fiber, carbohydrate). (ii) Vitamin (vitamin
C). (iii) Minerals (Iron).
NUTRITIONAL ANALYSIS
Nutritional analysis was done as described in the table given below
Parameters Determination methods Reference
Moisture content Oven method Sadhasivam and Manikam, 2008
Ash Muffle furnance Sadhasivam and Manikam, 2008
Crude fibre Alkali treatment method Sadhasivam and Manikam, 2008
Carbohydrate Anthrone Sadhasivam and Manikam, 2008
Protein Kjeldahl Sadhasivam and Manikam, 2008
Iron Spectrophotometer Sadhasivam and Manikam, 2008
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Chlorophyll Spectrophotometer Sadhasivam and Manikam, 2008
Vitamin - C Iodine titration method B.K.Sakhale et al
3. RESULTS AND DISCUSSIONS:
Drying Characteristics
The time required for drying in different drying condition is shown in Fig.4.2. There
was wide variation in drying time. The hot air oven drying method took least time of 140
minutes for drying due to higher temperature and the moisture content dried Moringa leaves
was about 10.3%. In shade and sun drying methods required maximum time of about 240 and
200 minutes to reach the final moisture content of 12 – 14%. The rate of moisture removal in
hot air oven drying was much faster than the sun and shade drying. The final moisture content
of dried leaves was in the range of 8-15%. The moisture content of Moringa leaves in hot air
oven drying at 70˚c was comparatively low because of higher temperature. In shade drying the
moisture content is higher because of lower temperature.
The change in moisture content with respect to time for controlled, Nacl and Na2Co3
treated Moringa leaves are shown in the figure 4.2, 4.3, 4.4.In fenugreek samples for fresh
leaves the moisture content was in the range 77.8% (Pallavi Joshi and Dipika Mehta, 2010)
Protein Content
The protein content in the controlled, Nacl and Na2Co3 treated dried leaves was in
the range of 20.42 - 26.78 g per 100 g. Maximum protein content of 27.4 g was in the shade -
dried moringa leaves treated with Na2Co3 and the minimum was in the oven dried at 70˚C
treated with Nacl. At lower temperature the protein content at 50˚C is 23.75 g when compared
to sun and oven drying at 60 and 70˚c which is about 16 – 18 g respectively. The difference in
the protein content of the dried moringa leaves was shown in fig 4.5.
Fibre Content
The fibre content in the dried moringa leaves was in the range of 5.3 to 8.8g with
the highest level in shade dried moringa leaves 8.1g followed by sun dried 7.92g and the
minimum values of fibre were found in oven dried moringa leaves at 70˚C which is about
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5.12g/100g of moringa leaves as shown in fig 4.7. Shade drying treated with Na2Co3 contains
higher fibre content when compared with oven dried moringa leaves. At higher temperature
the fibre content is low, as fibre is heat sensitive.
Carbohydrate Content
Carbohydrate content of moringa leaves was found to be in the 34.76g/100g.
Sample which was shade dried and treated with Na2Co3 contains higher carbohydrate content
of 34.45g than the oven dried sample at 70˚C which is about 24.34g respectively. Oven drying
at 50˚C contains carbohydrate content of about 25 - 27g.
Iron
Fresh drumstick leaves have an iron content of 0.085 mg/ 100 g of iron. Maximum
amount of iron content was in the shade dried moringa leaves 16.21 mg/ 100 g leaf powder
followed by sun dried moringa leaves 15.12 mg/ 100 g leaf powder and it was the lowest in
oven dried moringa leaves at 70˚C is 9.42 mg/ 100 g leaf powder.The difference in the iron
content of the dried moringa leaves was significant as shown fig 4.5
Chlorophyll Content
The maximum retention of chlorophyll was in shade dried moringa leaves is
2.7mg and followed by oven dried moringa leaves at 50˚C is 2.2 mg. Shade drying though
took longer time than sun and oven drying. Shade drying treated with Na2Co3 has the
maximum color retention than shade drying with Nacl. The difference between the dried
moringa leaves of drumstick leaves was significant.
Vitamin C
Vitamin C content of the dried leaves was less than the fresh moringa leaves. The
maximum amount of vitamin C was in shade - dried moringa leaves 12.80 mg as in this
technique the leaves were not exposed to direct heat and air. As vitamin –C is heat sensitive 60
and 70˚C vitamin C content is 6-8mg which is relatively low. Maximum amount of Vitamin-C
is retained in shade drying treated with Na2Co3 which contains 12.80 mg/100 g of moringa
leaves followed by oven dried at 50˚c is 11.8 mg/100 g of moringa leaves.
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Fig.2 Drying characteristics for untreated moringa leaves
Fig.3 Drying characteristics for pretreated Na2Co3 moringa leaves
Fig.4 Drying characteristics for pretreated NaCl moringa leaves
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Fig.5 Effect of drying method on temperature on protein content of moringa leaves
Fig.6 Effect of drying methods and temperature on CHO content of moringa leaves
Fig.7 Effect of drying methods and temperature on fibre content of moringa leaves
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Fig.8 Effect of drying methods and temperature on iron content of moringa leaves
Fig.9 Effect of drying methods and temperature on chlorophyll content of moringa leaves
Fig.10 Effect of drying methods and temperature on vitamin-c content of moringa leaves
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4. SUMMARY AND CONCLUSION:
Drying of drumstick leaves resulted in concentration of nutrients. The shade drying of
leaves had high nutritional properties during the process which increased the consumer
acceptance of the product than the outer drying methods. Pretreatment the sample with 2%
Nacl and 0.1% Na2Co3 helped in better retainment. The dried sample at 70°C took less time to
dry until the desired moisture content of about 8.9%. From the studies conducted it can be
concluded that: The best method for drying of drumstick leaves was shade drying treated with
Na2Co3 as it showed the higher values of nutritional content in iron - 16.3mg, CHO - 33.86g,
fibre - 8.18g , protein - 27.40g , Vitamin-C – 13.21mg, chlorophyll content-3.1 mg
respectively. Another reason for this conclusion is its lower nutritional loss in shade drying
treated with Na2Co3 and colour retention is high. The moringa leaves at 70ᵒC shows the higher
nutritional loss because of higher temperature. Next to shade drying, moringa leaves treated
with Na2Co3 in hot air oven at 50˚C shows best nutritional value. So, drying of drumstick
leaves promotes wider application by in corporating in food products. For further studies, the
parameters like drying temperature, different pretreatment and by varying moringa leaves
thickness, etc., can be analysed for the best results.
REFERENCE
1. Aletor O and Abiodun A.R. (2007). Nutrient and antinutrient components of some
tropical leafy vegetables. Food Chem.,53:375-379.
2. Arun S. Mujumdar and Sakamon Devahastin “Fundamental principles of drying”
Exergex, Brossard, Canada (2000)
3. Bamji, Mahtab.S, 2008 ”Maternal nutritional status and practices and perinatal,
neonatal morality in rural Andhra Pradesh ,India”, Indian journal of medical research
127.1:44
4. Bajaj, M., Aggarwal, P., Minhas, K.S. and Sidhu, J. S., 1993, Effect of blanching
treatments on the quality characteristics of dehydrated fenugreek leaves. J. Food Sci.
Tech., 30(3): 196-198.
Page
287
5. Chacko, M. and Khyrunissa B., 2007, Eating behavior and nutrient intake among
adolescent girls from middle income families. The Indian J. Nutr. Diet.,44(7): 367-373.
6. Chandrashekhar, U., Kowsalya, S. and Eapen, D., 2000, Retention of beta carotene
from selected greens and absorption of beta carotene from pumpkin leaves in adults.The
Indian J. Nutr. Diet.,37: 233-239.
7. Dharwad, Pushpa Bharati,2008 “Dehydration of amaranthus Leaves and its quality
evaluation.” Karnataka Journal Of Agricultural Sciences 26.2
8. Deepa, K. S., 2002, Nutritional and health profile during menarche and seasonal
variations in iron status. M. H.Sc. Thesis, Uni. Agri. Sci., Dharwad.
9. Gupta, D. K., Baburao, N. and Jayaraman, K. S., 1999, Improvement in rehydration
and shelf life stability of hot air dried and sun dried cabbage by pre-drying treatment.
Indian Food Packer, 53(6): 51-60.
10. Kaveri, G. V., Gupta, S., Lakshmi, J. A. and Prakash, J. 2004. Physiochemical
characteristics and sensory attributes of wheat-based “Papads” incorporated with green
leafy vegetables. Journal of Food Quality 27: 459 - 470.
11. Kasturiba, B., 1999, Promotion of vitamin A status through horticulture intervention.
Ph.D. Thesis, Uni. Agri. Sci., Dharwad.
12. Kowsalya, S., and Vidhya, M. R., 2004, Nutritive value of selected dehydrated green
leafy vegetables. The Indian J. Nutr. Diet.,41: 279-286.
13. Lakshmi, B. and Vimala, V., 2000, Nutritive value of dehydrated green leafy vegetable
powders. J. Food Sci. Tech., 37(5): 465-471.
14. Lalitha.R., and Sathya.K., 2003 Enrichment of instant food mix with beta carotene
through green leafy vegetables: acceptability characteristics. Proceedings of international
food conference;SS 02:75
15. Mosha, T. C., Pace, R. D., Adeyeye, S., Mtebe, K. And Laswai, H. S. 1995. Proximate
composition and mineral content of selected Tanzanian vegetables and the effect of
traditional processing on the retention of ascorbic acid, riboflavin and thiamine. Plant
Foods for Human Nutrition 48(3): 235 - 245.
16. Negi P. S. and Roy S. K. 2000. Effect of blanching and drying methods on β-carotene,
ascorbic acid and chlorophyll retention of leafy vegetables. Lebensmittel Wissenchaft und
Technologie 33(4): 295-298.
Page
288
17. Negi, P. S. and Roy, S. K., 2001, Effect of drying conditions on quality of green leaves
during long term storage. Food Res. International, 34: 283–287.
18. PallaviJoshi and Dipika Mehta, 2010. Effect of dehydration on the nutritive value of
drumstick leaves
19. Pandhre GR, Satwase AN, Hashmi SI (2011) Effect of different pretreatments and
drying methods on color characteristics fenugreek leaves. Int J Cur Sci Res 1: 115- 119.
20. Prameela, Y., Chittemma Rao, K. and Sarojini, G., 1995, A comparative study on the
nutritional status of rural adolescent girls and boys (11-18 years) in Andhra Pradesh. The
Indian J. Nutr. Diet.,32: 175-179.
21. Premavalli, K. S., Jamudar, T. K. and Madhura, 2001, Processing effect on color and
vitamins of green leafy vegetables. J. Food Sci. Tech., 38(1): 79-81.
22. Saroj-Dahia., 2002, Nutritional status assessment of pregnant women from Hisar city
of Haryana. Nutrition and Health, 16(3): 239-247.
23. S. Sadasivam, A. Manickam (2008) , Biochemical methods :1-19. Published by New
Age International (P) Ltd., Publishers.
24. Singh, U., Sagar V. R., Behera, T. K., Suresh Kumar P., 2006, Effect of drying
conditions on the quality of dehydrated selected leafy vegetables. J. Food Sci. Tech.,
43(6): 579-582.
25. Singh, H., Bawa, A. S. and Ahmed, J., 1997, Dehydration characteristics of some
green leafy vegetables. Indian Food Packer, 51(2): 5-13.
26. Singh, P., and Awasthi, P., 2003, Sensory and nutritional quality evaluation of green
leafy vegetable (GLV) powder incorporated food products. Proceedings of International
Food Conference, SS-07: 77.
27. Unde, P.A., Padian, S.M. and Chaudhari, R. S., 2000, Osmotic dehydration of leafy
vegetables. Beverage and Food World, 26(1): 26-27.
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