Category Archives: Volume 26 No. 1 & No. 2 (2004)

Bioassay-guided isolation of the antimicrobial compounds of Coleus amboinicus Loureiro (Lamiaceae)


Author(s): E. A. Vasquez1, W. Krause2, J. Conrad2, B. Volger2, C. Zebitz3 and B. M. Rejesue3

Abstract

The essential oil of the aerial part of Coleus amboinicus showed antibacterial activity against Bacillus subtilis (gram +) and Pseudomonas fluorescens (gram -) and antifungal activity against Cladosporium cucumerinum. Bioassay-guided fractionation revealed that carvacrol and ß-caryophyllene-4,5-oxide were the major contributors to the antimicrobial activity of the essential oil. The sesquiterpene α-humulene and monoterpenes α-pinene, α-terpmene and cymene present in significant amounts were inactive.

Keywords : Coleus amboinicus, essential oil, antibacterial, antifungal, carvacrol, caryophyllene-4,5-oxide

Full PDF :
pdf

Characterization of nutrient deficiency symptoms in sweetpotato through farmer-scientist participatory approach


Author(s): Anabella B. Tulin, Victor B. Asio, Dindo M. Campilan and Shigenao Kawai

Abstract

The nutritional disorders in the leaves, shoots, and root systems of sweetpotato variety PSB SP-17 were evaluated using the solution culture technique. Nutrient deficiency symptoms were established for the following elements: nitrogen, phosphorus,potassium, magnesium, calcium, sulfur, iron and micronutrients. Thirty-six healthy stem cuttings of sweetpotato were allowed to root for one week before placing them in culture bottles containing the nutrient solutions representing the various treatments. The sweetpotato cuttings were grown in culture bottles for more than two months and visible deficiency symptoms of each element were noted as they occur in the leaves and roots. Results showed that each nutrient element has a characteristic deficiency symptom there were also some similarities in the general performance of sweetpotato in nutrient deficient culture solutions. These similarities include the stunted growth of the plant and general yellowing of the leaves and reduced root biomass.
After the symptoms were established in the laboratory, farmers from two sweetpotato producing towns in Pinabacdao, Samar and Dulag, Leyte, Philippines were asked to identify the symptoms using their own indigenous knowledge and perception. Farmers’ concept of crop health and assessment of deficiency symptoms were likewise noted.

Keywords : nutrient deficiency symptoms,farmer- scientist participatory characterization, sweetpotato variety, PSB Sp-17

Full PDF :
pdf

Evaluation of the technical performance of root crop processing machines for sweetpotato grates and flour production


Author(s): D. L. S. Tan1, K. Miyamoto2, K. lshibashi3, K. Matsuda4 and T. Satow5

Abstract

The performance of the root crop processing machines used in the production of sweetpotato grates and flour was determined. The machines included the Philippine Root Crop Research and Training Center (PhilRootcrops) pedal-operated root crop chipper/ grater, hydraulic presser, spinner, motor-operated attrition grinder, flour finisher, and cross-beater mill. Each machine was evaluated based on the following parameters: operating power with and without load, revolution per minute (rpm), capacity, fineness moduhis, dimensions of chips and grates, and percent recoveries.
The chipping capacity of the (PhilRootcrops) Chipper/Grater increased as the blade rpm increased (350 to 650 rpm), together with the amount of crumbs present in the chips, but the average weight of the chips decreased. On the other hand, the grating capacity increased and the fineness modulus of the grates decreased with an increase in blade rpm at the same rpm range. The grating operation had the most pronounced power fluctuation among the operations evaluated. Pressing the grates using the hydraulic presser at 5 kg loading rate reduced the moisture content level of grates from more than 60% to about 50%. Using the

Keywords : sweetpotato, grates, chips, flour, root crop processing machines

Full PDF :
pdf

Development of an electronic moisture meter for abaca fiber


Author(s): Feliciano G. Sinon and Alberto C. Martinez Jr.

Abstract

An electronic, portable, cheap and easy-to-operate moisture meter was developed and fabricated using the resistivity—conductivity principle of operation which states that the presence of moisture in the fiber conducts electrical current from one terminal end to the other. Its circuitry followed that of the modified wheatstone bridge and used an LM 324 Op Am Integrated circuit.
Results of the calibration studies showed highly significant relationships between the meter reading and the oven drying method even at the fiber pressure of only 100 g/ cm= (estimated at 4 kg pressure at the test probe handle). Further studies using fiber samples of zero and 14-blade serrations revealed highly significant relationships between the moisture reading and the oven drying method with an R-value of 0.986 and 0.976 and tendline equations of y = 2.34 + 1.07x and y = 0.8376x, respectively. This means that the meter is still capable of reading moisture content of abaca fiber at different classifications with greater accuracy and reliability.
Potential end-users’ acceptability evaluation of the meter revealed higher acceptability rating from the farmers than the traders.

Keywords : moisture meter, abaca moisture, fiber moisture, moisture content

Full PDF :
pdf

Antifungal activity of six botanicals against root crop diseases


Author(s): Manuel K. Palomar, Erlinda 0. Landerito, Avelina P. Molato, Doreen S. Cayanong and Victoria G. Palermo

Abstract

Sequential extractions were done in selected botanicals to test their bioactivity against important fungal pathogens of root crops. Extracts considered as potential fungicide were ampalaya (Momordica charantia) crude ethanolic/acetonic extract to Colletotrichum gleosporoides and Phytophthora colocasiae, asyang (Mikania cordata) crude ethanolic/ acetonic extract to P colocasiae, ginger (Zingeber officinale) crude ethanolic/acetonic extract to Sphaceloma batatas, kamantigue (Impatiens balsamina) crude ethanolic/acetonic extract to Sclerotium rolfsii, S. batatas and C. gleosporioides, olasiman (Portulaca oleracea) crude ethanolic extract to S. rolfsii and S. batatas, and saluyot (Corchorus olitorius) crude ethanolic extract to S. batatas and P colocasiae. Phytochernical screening revealed that secondary metabolites such as flavonoids, steroids and terpenoids were present in the plants while only saluyot contained tannins and polyphenolic compounds.Flavonoids caused complete inhibition of colony growth of S. batatas. For S. rolfsii, the following flavonoidal extracts were fungicidal: ampalaya (M.charantia) using ethanol and acetone, ginger (Z. officinale) using ethanol, and kamantigue (I. balsamina) or olasiman (P oleracea) acetonic extract to C. gleosporioides. Excised leaves inoculated with P colocasiae treated with asyang (M. cordata), olasiman (P oleracea), and ginger (Z officinale) ethanolic/ acetonic extracts showed no infection after 6 days, which indicates superiority to other extracts and that of the control. Planting treatment of yam setts with ampalaya (M. charantia) ethanolic/acetonic extracts followed by regular spraying with the same extract up to 6 months after planting (MAP) showed the best protection against yam anthracnose with degree of protection better than Benlate. Furthermore, taro plants treated with olasiman (P oleracea) ethanolic extract exhibited the highest percent disease control and least percent tuber surface infection by S. rolfsii.

Keywords : biofungicide botanicals, plant extracts, secondary metabolites, bioactive

Full PDF :
pdf

Deep bed peanut drying using Hukill’s Analysis


Author(s): L. M. Diamante1, M. S. Chinnan2 and P. Mallikurjunan2

Abstract

A simple model based on Hukill’s Analysis was used in the simulation of deep bed drying of peanuts at various drying conditions. The model was first evaluated using published drying data and then actual drying experiments at different conditions. The results showed that the simulation model could adequately describe the deep bed drying of peanuts.
The effects of bed initial and final moisture contents, drying temperature, air humidity, airflow and bed depth on the drying time and moisture content of various layers within the bed of peanut pods were evaluated using the simulation model.
Drying temperature had the most significant effect on drying time followed by bed initial moisture content, bed final moisture content, air humidity, airflow and bed depth, respectively. As drying temperature, bed final moisture content and airflow increased, the drying time decreased. Conversely, as the bed initial moisture content, air humidity and bed depth increased, the drying time also increased.
The bed final moisture content had the greatest effect on the bottom, middle and top layer moisture of peanut pods among the factors studied. The lower the bed final moisture content, drying temperature, bed initial moisture content, bed depth and air humidity, the lower the moisture difference between the bottom and top layers. Conversely, the lower the airflow, the higher the moisture difference between the bottom and top layers.

Keywords : peanut, deep bed drying, Hukill’s Analysis, simulation

Full PDF :
pdf

Moisture adsorption isotherms of dried mangoes at a temperature range of 25 to 45°C


Author(s): L. M. Diamante1, Ken-ichi Ishibashi2 and Kazunori Hironaka

Abstract

A study was conducted to determine the adsorption isotherms of dried mangoes at different temperatures. The results showed that the adsorption isotherms of dried mangoes at different temperatures were type III according to the BET classification. At a water activity <0.50,the equilibrium moisture content of samples at a given water activity increased as the temperature decreased. But at a water activity >0.50, the equilibrium moisture content of the samples increased as the temperature increased. The adsorption isotherms were fitted with 8 two-parameter equations (Bradley, Caurie,Halsey, Henderson, Kuhn, Linear, Oswin and Smith). The Caurie, Henderson and Oswin equations gave consistently high coefficients of determination when fitted to the adsorption isotherms of dried mangoes at different temperatures. However, further evaluation of the equations using the mean relative percentage deviations showed that the Caurie equation gave the best fit for describing the sorption data. A four-parameter modified Caurie equation was derived for predicting the equilibrium moisture content of dried mangoes as a function of water activity and temperature. Using the derived equation, the water activities of dried mangoes at different temperatures and constant moisture content were determined and used for obtaining the net heat sorption. The net heat sorption for dried mango decreased with increasing moisture content and can be expressed using linear equations for moisture ranges below 15% dry basis and above 15% dry basis.

Keywords : adsorption isotherms, dried mangoes, temperature, water activity, Caurie equation, net heat of sorption

Full PDF :
pdf

Response of corn to chicken dung and rice hull ash application and mycorrhizal fungi inoculation


Author(s): Luz G. Asio1 and Alfredo B. Escasinas2

Abstract

This study evaluated the growth and yield responses of corn to chicken dung and rice hull ash application as well as to mycorrhizal fungi inoculation. The experiment was laid out in a split-plot in Randomized Complete Block Design consisting of three replications. Vesicular-arbuscular mycorrhizal (VAM) inoculation served as the main plot while application of fertilizer was designated as the sub-plot. The fertilizer treatments included the following: T0– control, T1– inorganic fertilizer (60-60-60 kg ha-1 N, P2O5, K2O), T2– chicken dung alone (60 kg ha-1N) and T3– chicken dung (as in T2) + 30 kg ha-1 rice hull ash. The experimental area had an alluvial clay loam soil.
Results showed that VAM inoculation significantly increased the total N but not the total P, K, and Ca contents of the tissue of corn plant. However, VAM inoculation did not significanity affect the grain yield and the agronomic characteristics of corn. In contrast, fertilization using either inorganic fertilizer, chicken dung or chicken dung plus rice hull ash enhanced the early tasseling and silking but not emergence and maturity of corn. The application of fertilizers significantly increased plant height as well as the fresh stover yield compared to the control.
The inorganic fertilizer, chicken dung, and c hicken dung plus ricehull ash, significantly increased the number of ears per plant, ear length, number of grains per ear, weight of 1000 seeds, grain yield and harvest index. The use of chicken dung combined with rice hull ash for corn production is a good substitute for the inorganic fertilizer in increasing grain yield.

Keywords : chicken dung, rice hull ash, corn, nutrient uptake, mycorrhizae

Full PDF :
pdf

Yield and economic returns of peanut and sweetcorn as influenced by timing of planting the crops in an intercropping scheme


Author(s): Ulysses A. Cagasan1 and Benjamin Agarcio2

Abstract

This study was conducted to evaluate the growth and yield of peanut and sweet corn as influenced by timing of planting the crops in an intercropping scheme; determine the appropriate timing of planting peanut and sweet corn in an intercropping scheme for optimum land productivity; and determine the economics of growing peanut in combination with sweet corn as influenced by timing of planting the crops.
Most of the agronomic characteristics, yield and yield components of peanut and sweet corn were significantly affected by timing of planting the crops. Sweet corn planted 2 and 3 weeks ahead of peanut gave higher total yield in tons per hectare than sweet corn planted later than peanut.
Planting sweet corn 3 weeks ahead of peanut (T3) gave the highest land equivalent ratio (LER) of 1.62, which means that such practice was 62% more productive than growing peanut or sweet corn as monocrop. It also gave the highest gross margin of PhP 52,157.00 per hectare.

Keywords : peanut, sweet corn, intercropping, timing of planting

Full PDF :
pdf