Effect of Drying Method on the Quality of Chesters (Heinsia crinita) *ALONGE, A. F. and ESSIEN, M. B. Department of Agricultural and Food Engineering, University of Uyo, Uyo, Akwa Ibom State, Nigeria ABSTRACT: The effect of sun drying and oven drying at 105oC on the nutritive composition of Heinsia crinita was investigated. The sample was divided into three groups represented as fresh (wet), sun dried for two (2) weeks and oven dried at 105oC to constant weight. The proximate analysis which includes moisture content, crude protein, ash, crude fibre, crude fat and the total carbohydrate content was carried out. The results for fresh sample were moisture content (40.11%), ash (2.68%), crude protein (1.75%), crude fibre (17.50%), crude fat (19.50%) and total CHO (81.54%) and that of the sun-dried sample were moisture content (15.45%), ash (9.59%), crude protein (3.13%), crude fibre (24.50%), crude fat (9.50%) and total CHO (62.17%). While these of the oven-dried sample were moisture content (14.22%), Ash (14.23%), crude protein (3.50), crude fibre (28%), crude fat (4.50%) and total CHO (64.45%). The levels of these nutrients were generally increased both by sun drying and oven drying at 105oC except for the crude fat and total CHO which decreases, with a greater increase when oven dried. Drying curves were plotted for both drying methods to further investigate the effects of drying on the nutrient composition of chesters (Heinsia crinita). Keywords: Drying; Moisture content, proximate compostion; Heinsia crinita INTRODUCTION Traditionally, the people of South Eastern Nigeria and B o t h v e ge t a b l e ( c h e s t e r s a n d B u s h a p p l e l e a v e s ) a r e other West African countries utilize the plants Chester usually found in the tropical rain forest and it is sparsely (Heinsia crinita) for both food and therapeutic purposes. distributed. Figures 1 and 2 shows the fresh and dried The plant called ‘Atama’ (chester) in Efik local dialect of chester leaves. These shrubs are most common in West Nigeria, have for several hundreds of years been exploited Africa mostly in Nigeria and also it might be found in some b y t r a d i t i o n a l h e r b a l i s t fo r t h e t r e a t me n t o f v a r i o u s African countries like Ghana, Cameroon, Ivory Coast, ailments, including typhoid fever, diarrhoea candidiasis, Congo, Uganda and Upper Votta (Bassir and Umoh, 1975). etc. These plant can be used in various forms to treat In Nigeria, the plants are widely distributed in Ika, Itu, some diseases and this qualifies it to be called medicinal Etim Ekpo, Oron, Onna, Abak, Uyo, Ibesikpo Asutan and plant (Andy, et al.,2008). Etinan Local Government Area in Akwa Ibom State. It is There are about five or more varieties of chester (Heinsia also will distributed in some Local Government Area in crinita), many of these varieties are edible, other not Abia, Cross River, Imo and Enugu States of Nigeria. All w h i l e o t h e r s a r e u s e d b e c a u s e o f t h e i r me d i c i n a l these are in the South Eastern State of Nigeria. properties. The very commonly known one are the white Generally, chesters (Hein sia crin ita) are consumed as varieties (Ibibio and Efik) “afia atama” (The ‘Ekoi atama’ cooked complement to the major food stuffs like cassava, refers to the ethnic region called ‘Ekoi’ which is found in cocoyam, guinea corn, maize, millet, rice and plantain. Northern part of South Eastern Nigeria), Riverside Atama Infact, most of the meals prepared using these staples are (“Atama Idim”). The name implies that this specie is seen as incomplete if a good amount of cooked green found at the bank of rivers streams etc. and non-edible leaves do not accompany them. Due to the method of specie (“Atama Ekpo”) meaning that it kills if eaten processing chester (Heinsia crinita) for preservation, it is because it contain very toxic chemicals. evident that the nutritive value of the vegetable can be C orrespo n de n ce t o A l on ge , A . F. ; a ki n de le a lo n ge @u n iu y o. ed u .n g Proceedings of the 2014 International Conference of the Nigerian Institution of Agricultural Engineers held at the Federal University of Technology, Akure, Nigeria, 22nd-26th, September, 2014. Pp 2 8 5 Effect of Drying Method on the Quality of Chesters (Heinsia crinita) Figure 2: Sun drying of Chester Figure 1: Fresh Chester leaves affected, for example by spreading the leaves in the period of time they are left to dry are likely to affect their nutritive value. There is little or no information on the effect of drying of the vegetable for preservation before it is being used in preparing soups. This research work will consider the chemical evaluation of the nutritive value of dried samples of chester (Heinsia crinita) compared with fresh samples. H e i n s i a c r i n i t a ( c h e s t e r ) ha s a c h a r a c t e r i s t i c a r o ma which could possibly be attributed to the presence of essential oils, terpenenes and other principal essential oils that convey distinctive taste and aroma which also contribute to its very high medicinal value as enumerated below: (1) O r a l e nq ui r y fr o m ind i ge ne s o f Ab a k a nd herbalist revealed that chester is used to cure s t o m a c h p a i n s u c h a s u l c e r wh e n e a t e n unprocessed i.e. with the bitter in soap. It was also reported when burned, ground, dissolved in water and taken for few day, it is effective in the treatment of dysentery. (Ebana et al., 1995). (2) The dry leaves are pounded, steeped in water and applied to rheumatic joint to relief pains. (3) The ground dry leaves are rubbed on the forehead for the treatment of migraine headache. (4) A decoction of the root of Heinsia crinita is used f o r t h e t r e a t me n t o f g e n e r a l d i s e a s e s a n d a poultice of the leave is used for skin rashes and head lice. (5) T h e s t o c k a n d b r a n c h l e t a r e u s e d a s c h e wi n g stuk for dental hygiene by those who have mouth infection such as tooth and gum decay. A lot of claims have been made on the nutritive va lue a nd medi ci nal val ue of He in sia c rin it a b y traditionalist, herbalist etc., some scientist have carried out various researches confirming the nutritive values of Heinsia crinita which is a green vegetable eaten mostly in the Eastern region of Nigeria and also in Cameroon. Hence this paper presents the effects of the drying method of processing on the nutritive values and quality of chester. CHEMICAL COMPOSITION OF CHESTER (Heinisa Crinita) Reports in literature have been given on the nutrient and Isong, 1990). The three were the white, black and Ekoi composition of Heinsia crinita. Nutritionally vegetables varieties the chemical analysis of the leave of Heinsia are valuable because they serve as a cheap source of crinita showed in terms of % dry matter. Obsolete dry different types of nutrient. Vegetable also as life saving matter (30.33%) crude protein (15.10%), crude fibre (13.90% supplement to nutrient meager diet in time of stress as ether extract (3.02%) N – free extract (59.30%) total ash well the cans during the civil war of Nigeria (Eyo et al., (8.68%) calcium (11.07%) and phosphorus (0.17%) (Eyo et 1983). The nutrients and antinutirent composition of al.,1983). three varieties of Heinsia crinita were reported by (Umoh Proceedings of the 2014 International Conference of the Nigerian Institution of Agricultural Engineers held at the Federal University of Technology, Akure, Nigeria, 22nd-26th, September, 2014. Pp 2 8 6 Alonge, A.F. and Essien, M.B. The proximate composition of the leaves in % dry weight basis has been found to be carbohydrate (50.1) ash (8.9), fat (19.1) protein (15.9) and crude fibre (19.1) protein (15.9) and crude fat (5.4) the moisture content in terms of wet weight was found to be 25.4% (Eyo et al., 1983). The black variety of Heinsia Crinita (chester) contains the highest hydrocyanie acid and tannio contents in term of toxicants. It is believed that it is as a result of its very dark colour and of course the must bitter of all. It also contains the highest alkaloid content (Umoh, 1990). DEHYDRATION OF VEGETABLES Dehydration of vegetable is one of the oldest from of food preservation techniques known to man and consists primarily of establishment engaged is sun drying or artificially dehydrating of vegetables. Although food p r e s e r v a t i o n i s t h e p r i ma r y r e a s o n f o r d e h yd r a t i o n , d e h y d r a t i o n o f v e g e t a b l e s a l s o l o we r s t h e c o s t o f packaging storing and transportation by reducing both the weight and volume of the final product. Given the improvement in the quality of dehydrated foods along with the increased fo cus fo r instant o n convenience foods the potential of dehydrated vegetable is greater than ever (Gooding, 1962). Process Description Dr ie d ve ge ta b l e ca n b e p r o d uc ed b y a va r i et y o f processes. These processes differ primary by the type of drying method used, which depend on the type of food and the type of characteristic of the final products. In general dried of dehydrated vegetable undergo the following process step: predrying treatment such as size selection (Ene-Obong and Obizoba, 1996). Predrying t r e a t me n t s p r e p a r e s t h e r a w p r o d uc t f o r d r yi n g o r dehydration and include raw product preparation. Raw p r o d uc t p r ep ar a ti o n s in clu d e s el ec ti o n an d so r t in g, washing next, the product is cut into the appropriate shape or form (i.e. slices). Drying Rate Curves The removal of moisture from a typical food product will follow a series of drying rates, as illustrated in Figures 3 and 4. The initial removal of moisture (AB) occurs as the product and the water within the product experience a slight temperature increase. Following the initial stages of drying, significant reductions in moisture content will occur at a constant rate (BC) and at a constant product temperature. The constant-rate drying period occurs with the product at the wet bulb temperature of the air. In most situations, the constant-rate drying period will continue until the moisture content is reduce to the critical moisture content. At moisture contents below the critical moisture content, the rate of moisture removal decreases with time. One or more falling-rate drying period (CE) will follow. The critical moisture content is well defined due to the abrust change in the rate of moisture removal (Singh, 2001). M o istu r e c o n te n t Source: Singh and Heldman, (2001). A B C D Drying time Fig. 3: Drying Rate Curve Source: Singh and Heldman, (2001). Fig. 4: Drying Rate Curve Source: Singh and Heldman, (2001). Proceedings of the 2014 International Conference of the Nigerian Institution of Agricultural Engineers held at the Federal University of Technology, Akure, Nigeria, 22nd-26th, September, 2014. Pp 2 8 7 Effect of Drying Method on the Quality of Chesters (Heinsia crinita) MATERIALS AND METHODS The sample chester (Heinsia crinita) to be used was % Protein = 6.25 x value obtained from above. c o l l e t e d a t a l o c a l fa r m i n I b e s i kp o As ut a n Lo c a l Where titrate = Blank reading x volume of acid used. Government Area of Akwa Ibom State. The leave was The blank reading = 0.14. separated from the stalk and washed thoroughly and dried using both sun and oven at 70oC. Thereafter, the Determination of Crude Fibre (A.O.A.C. 1975) proximate analyses of chester (Heinsia crinita) samples 2g of the fat free samples were obtained after either extracts performed. was made from the two different samples, and the method used was based on the separate exhaustive extraction of Materials Used substance by boiling 1.25% of H2S04 and later in 1.25% NaOH solution. The remains after the exhaustive was The materials, equipment and apparatus used included o obtained by subtraction the amount of insoluble matter Oven (70 C), Kj ed ahi Ap paratus (for p ro tein determination), Knife, Weighing balance and crucibles, after ashing from the dried weigh of sample. The crude Water, Filter paper, Halting mandle, Spatula and tong. fibre content was calculated from the loss in weight of Other are desiccator, Bunsen furnace, Multiple Soxhlet crucible and it contents after ignition. extractor, pipette and burettes, beakers and 100ml conical flask. Determination Of Crude Fat (Petroleum Ether A.O.A.C. 1975) Determination of Moisture Content (A.O.A.C. 1999) The crude fat was extracted from 2g of each sample of the 3g of the fresh samples of the mature leaves from the leaves using a petroleum ether and soxhlet extractor. The two different plant samples were dried to a constant lipid content of each samples was evaporated from the o weight at a temperature of 70 C in a hot air circulating petroleum ether from the extractor flasks. oven. The weight loss after cooling and reweighing % Ether Extract = Weight of Extract x 100 was express as the moisture content. This is expressed Weight of Sample in % wet weight using this formula. % moisture (wet weight) = Determination Of Ash Content (A.O.A.C. 1975) Loss in weight on drying x 100 This was determined from the loss in weight that was left Initial weight of sample after incineration of each sample at S50oC for over night in a murfle furnace. This temperature was high enough to allow organic mater to be burnt off without decomposing Determination Of Crude Protein (Microkjeldahl, the ash constituent. A.O.A.C. 1975 Method) % Ash = Weight of ash in grams x 100 0.4g of the fresh sample of mature leaves from the two Weight of oven-dried sample (g) N. different plants was changed to slummy (NH4)2504 by digestion with concentrated tetraoxosulphate vi in the Determination Of Carbohydrate (A.O.A.C. 1975) present of Kjedahl catalyst. The ammonium was distilled The carbohydrate was determined by subtracting the crude in 6% boric acid. The nitrogen from ammonia with 0.14 libre, protein, lipid and ash from the total dry matter of the hydrochloric acid until a purples pink colour obtained sample. as the end point. This was calculate using this formula % N2 = 14 x 100 x 100 x 0.05 x titrate 1000 25 2 RESULTS AND DISCUSSION This section presents the experimental results in a tabular fo rm a nd a ls o the di sc us si ons. T he pr oximat e composition consists of moisture content, ash content, protein content, crude fibre content, fat content and the total carbohydrate content. Proceedings of the 2014 International Conference of the Nigerian Institution of Agricultural Engineers held at the Federal University of Technology, Akure, Nigeria, 22nd-26th, September, 2014. Pp 2 8 8 Alonge, A.F. and Essien, M.B. Table 1: Variation of nutrients in the fresh sa mple Nutrients Amount obtained (%) Moisture contents 4 0 .1 1 Ash 2 .6 8 Crude protein 1 .7 5 Crude fibre 1 7 .5 Crude fat 1 7 .5 0 Total carbohydrate 8 1 .5 4 Table 2: Variation of Nutrients in the Sun – dried Sample Nutrients Amount obtained (%) Moisture 1 5 .4 5 Ash 3 .1 3 Crude protein 2 4 .5 0 Crude fibre 9 .5 0 Crude fat 9 .5 0 Total carbohydrate 6 2 .1 7 Table 3: Variation of nutrients in the Oven-dried sample at 105oC Nutrients Amount obtained (%) Moisture 1 4 .2 2 Ash 1 4 .2 3 Crude protein 3 .5 0 Crude fibre 2 8 .0 0 Crude fat 4 .5 0 Total carbohydrate 6 4 .4 5 Table 4: Variation of Moisture Content with drying time at 105oC T(mins) Mass obtained (g) Moisture content (dry bone) 0 4 5 .2 8 0 .9 1 30 4 5 .1 5 0 .6 3 60 4 5 .0 6 0 .4 2 90 4 4 .9 7 0 .2 2 120 4 4 .9 0 0 .0 7 150 4 4 .8 8 0 .0 2 180 4 4 .8 7 0 210 4 4 .8 7 0 Moisture Content The moisture content determination was carried out in triplicates; hence, the average value was recorded. As heat was applied, the moisture content decreased with i n c r e a s e d i n d r yi ng t i me . T h e o v e n - d r i e d s a mp l e co ntained the least amo unt of moisture hence, oven drying is the best way to preserve the keeping quality of t h e H e i n s i a c r i n i t a . S u n d r i e d s a mp l e h a s m o i s t u r e fluctuation because the rate of moisture evaporation was n o t c o n s t a n t . T h e mo i s t u r e c o n t e n t c a n b e f u r t h e r explained from the drying curve as shown in Figure 5, where AB represents the ‘warming up’ region where there Proceedings of the 2014 International Conference of the Nigerian Institution of Agricultural Engineers held at the Federal University of Technology, Akure, Nigeria, 22nd-26th, September, 2014. Pp 2 8 9 Effect of Drying Method on the Quality of Chesters (Heinsia crinita) Fig. 5: Drying Curve Showing Moisture Content (dry bone) against drying Time Fig. 6: Drying Curve Showing Weight against time of Sun-drying i s i n i t i a l r e mo v a l o f mo i s t u r e a s t h e H e i n s i c r i n i t a experiences a slight temperature increase. BC represents the constant rate period while CD and DE represents the f a l l i n g r a t e p e r i o d . T h e h i g h mo i s t u r e c o n t e n t s i n b e li e ve d t o b e t he r e a s on fo r e a s y d i ge st i o n a nd assimilation of nutrients in the leave. Increase in crude fibre content using the open air drying and 10.5% increase using the oven drying method. The reason for the increase in the fibre content is as it is being dried up. Fibre is an indigestible plant material such as cellulose found in fruits and vegetables. It is vital to a healthy body as it usually comes wrapped around valuable foods, rich in nutrients, in protecting the digestive system. It also provides bulk to the food, helping it to pass easily along the gut. I n c r e a s i n g fi b r e i n t h e d i e t c a n h e lp wi t h we i g h t management and fat loss in several ways: it takes longer to eat, makes one feel full, it delays the release of glucose into the blood resulting in lower levels of insulin in the blood. High fibre diets are higher in carbohydrates that satisfied the appetite and tend to be less processed and contain less fat. Hence, drying is a good ways to increase the crude fibre content of a food item. The recommended daily allowance is about 18g per day. Ash Content T h e v a l u e o f t h e a s h c o n t e n t i s t h e me a n o f t h r e e replicates. The result shows that there is an increase in ash content of the leave as the temperature increases. There was 6.91% increase in ash content from the open air drying and 11.55% increase in ash content using oven drying method. The increase in ash content reflects that the amount of mineral preserved is also increasing. This increment improves the nutritive value and keeping quality of the leave. Crude Protein Content From the result obtained above, there was 1.38% increase in crude protein using the open air drying and 1.75% increase using the oven drying method. It is believed that this increase is as a result of concentration of protein a s mo i s t u r e e v a p o r a t e s o u t o f t h e l e a v e s d u e t o temperature increase. Crude Fibre The results of the crude fibre content for each sample are presented above. From the results these was 7%. Lipid Content From the result obtained above, there was 10% decrease in lipid content using the open-air drying and 15% decrease using oven drying. As has already been indicated, any food item rich in-fibre will affect the lipid content of that food item by reducing the lipid contents. As the fibre content increased, the lipid (fat) content also decreased. It is believed to lower blood cholesterol levels. Fat is a major source of energy. It enhances the transport of fat – Proceedings of the 2014 International Conference of the Nigerian Institution of Agricultural Engineers held at the Federal University of Technology, Akure, Nigeria, 22nd-26th, September, 2014. Pp 2 9 0 Alonge, A.F. and Essien, M.B. soluble vitamins, insulates and protects internal tissues and also contributes to the vital cell processes. Total Carbohydrate Content Fr o m t he r e su lts a b o ve , i t is e v id e n t t ha t the t o t a l carb ohydrate co ntent d ecrease b y 1 9.37 % using the open air drying and 17.09% using the oven drying method. The values of CHO were obtained from the addition of o ther nutr i ents i ncl ud i ng fi br e. T he se va lue s ar e comparatively high and can be attributed to the moderate levels of other nutrients. CONCLUSION fresh sample to ascertain the changes which tool place The effect of drying on the nutritive value of Heinsia during drying of the leaves. It was concluded that the crinita was studied successfully. A wet food material oven drying method was more effective as the amount of exposed to heated air experiences progressive loss of nutrients increases with drying time except for the fat and weight due to the removal of the three forms of water; carbohydrate content which both decreases. Hence, the first the free water, followed by the adsorbed water and nutritive value and keeping quality of Heinsia crinita can finally by the chemically bound water; moreover the heat be increased upon drying up. required to remove these forms of water increases in Families everywhere should make use of the oven drying that order, with the free water requiring the least heat m e t h o d o f t h e l e a v e s s i n c e t h i s s t u d y h a s s h o wn t h a t while the bound water requires the highest heat for its nutritive value of the leaves increased on dry up. Air and removal. In general, the extent o f mo isture removal moisture proof containers should be used to maintain the depends on temperature and humidity of the drying air. keeping quality of the dried vegetables. Both the sun drying method and the oven drying method were investigated and the results were compared to the BIBLIOGRAPHY Dye, W. B. (1956). Studies on Halogeton Glomeratus Weed. A.O.A.C. (19 75 ). 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