Category Archives: Volume 42 No. 1 (2020)

Physico-chemical properties of dehydrated seriales (Flacourtia jangomas (Lour) Raeusch) as influenced by sugar levels

Author(s): Heidi P. Paler2 and Lynette C. Cimafranca1*


Seriales (Flacourtia jangomas (Lour) Raeusch) is a wild and underutilized fruit growing in rural areas in the Philippines. This study explored the potential of seriales as dehydrated product. A single factor experiment arranged in completely randomized design was undertaken to evaluate the effect of sugar level (40, 50, 60, 70 & 80%) on the physico-chemical properties of dehydrated seriales. The procedure in determining the physico-chemical properties of dehydrated seriales fruit follows standard AOAC (1980) procedures. Results revealed that sugar level significantly affects the TSS, pH, moisture content, and water activity of the product.

Keywords: dehydrated fruit, Flacourtia jangomas, physico-chemical properties, sugar level

Annals of Tropical Research 42(1):128-136(2020)

Ultrastructure and fourier transform infrared spectrum of exopolysaccharide produced by Lactobacillus rhamnosus NBRC 3425

Author(s): Ivy C. Emnace1*


In the search for exopolysaccharide (EPS)—producing LAB strains as potential additive for industrial applications, EPS produced by Lactobacillus rhamnosus NBRC 3425 was subjected to partial characterization to provide further information on its structure and composition. The crude EPS was subjected to scanning electron microscopy (SEM), atomic force microscopy (AFM),transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). Results of TEM analysis confirmed that the test organism is an EPS producer due to the presence of an unstained, clear cell wall or halo that surrounds the bacterial cell typical of a capsular EPS. SEM analysis showed that the crude EPS has pores and spaces between particles. Atomic force microscopy (AFM) at a concentration of 10μg per mL revealed spike-shaped lumps with an average size of 17.81±2.89nm. The FTIR spectrum suggested the presence of hydroxyl (OH) groups of carbohydrate and carbonyl group (C=O). Results showed that based on its structural characteristics, such EPS has the potential for use as stabilizer in food products.

Keywords: atomic force microscopy, Fourier transform infrared spectroscopy, Lactobacillus rhamnosus, scanning electron microscopy, transmission electron microscopy

Annals of Tropical Research 42(1):117-127(2020)

Impact of the conditional cash transfer program’ on the monthly food expenditure of household beneficiaries

Author(s): Norberto E. Milla1*


Philippines is among the many countries which has a perennial problem on poverty. The country has made various ways to reduce its poverty rate; one is through conditional cash transfer (CCT) scheme. This study measured the impact of CCT Program, particularly on food consumption among its household beneficiaries using Propensity Score Matching (PSM). Impact is measured in terms of the Average Treatment Effect on the Treated (ATT) using four matching algorithms: Nearest Neighbor Matching, Caliper (Radius) Matching, Kernel Matching, and Local Linear Regression matching. Binary logistic regression was used to identify covariates influencing program participation which include having children who are 6-12 years old, education of the household heads’ spouses, marital status and sex of the household head, housing tenure, and ownership of household assets. Balance test indicates nonsignificant difference between 4Ps and non-4Ps beneficiaries across these covariates. Of the four matching algorithms, the Caliper (radius) matching generated ATT estimate with the least standard error. On the average, using the Caliper matching method, the monthly food expenditure of the household beneficiaries have significantly increased by PHP501.39, Thus, the CCT program of the government has brought significant improvement on the household beneficiaries, not only on education, health, and nutrition but also on their monthly food expenditure. It is recommended that the implementation of the CCT program should be strengthened, sustained, and maintained properly and orderly to gradually alleviate the current poverty conditions in the identified poor barangays around the nation. Moreover, the implementing agencies should consistently monitor the proper and synchronized implementation of the program in order to wholly purge the intergenerational transmission of poverty which is a perennial experience of the households who belong to the poorest populace in the country.

Keywords: propensity score matching, nearest neighbor matching, caliper matching, kernel matching, local linear regression matching

Annals of Tropical Research 42(1):104-116(2020)

Characterization and prediction of household use of solar home system in Leyte Islands, Philippines

Author(s): Jacqueline M. Guarte1*, Joyce B. Maurillo2 and Jenefrey A. Niverba2


Under the Household Electrification Program ofthe Philippines‘ Department of Energy, 530 solar home systems (SHSs) with 30Wp capacity were installed in individual households in four island barangays (villages) in Leyte and Southern Leyte from 2013 to 2015. Aside from lighting with four LED bulbs,the SHS can also be used to listen to the radio or MP3 player, and charge a mobile phone. This paper examines household use of the SHS thru data collected from 299 beneficiaries interviewed in the period 2017-2018. Results indicated that while all households use the SHS for lighting, its other applications are not utilized as much. A sizable percentage of households are now using only the SHS for lighting in each island barangay. The use of the generator set (for a limited time at night) in partnership with the SHS remains dominant to be able to use the SHS lights longer. Kerosene lamp is now rarely used for lighting except in the absence of a barangay-owned generator set.
With a substantial percentage of households using the SHS for lighting only amidst its other applications, classification trees by island barangay were generated to identify the variables which will explain SHS use with both quantitative and qualitative household characteristics making up the predictor space. Although the classification trees grown are unique to each island barangay, age of the household head and annual household income are the consistent significant predictors (up to the third most important) followed by median age of the household members.

Keywords: rural electrification, renewable energy system, nonparametric method, classification trees

Annals of Tropical Research 42(1):79-103(2020)

Adlay (Coix Iacryma-jobi L.) and Napier grass (Pennisetum purpureum Schum.) intercropping and fertilization schemes as climate smart strategy for food and feed production

Author(s): Nello D. Gorne1* and Agripina R. Ardilla2


Adlay is considered an alternate staple food crop in the Philippines while napier is a versatile multipurpose fodder crop. Effective intercropping and fertilization strategies for the production of these crops could help address the problems on food and feed supply. The objectives of the study were to 1) evaluate the growth and yield of adlay with napier at various fertilization scheme; 2) determine the appropriate intercropping and fertilization schemes for maximum adlay production; 3) appraise the efficiency of intercropping scheme; and 4) assess the profitability of intercropping adlay with napier at various fertilization scheme. The study was laid out in split-plot with three intercropping scheme (C1=Monocrop adlay, C2=Adlay with napier at 1:1 row ratio, and C3=Adlay with napier at 2:1 row ratio) and five fertilization schemes (F0=Unfertilized, F1=120kg ha-1 N inorganic fertilizer, F2=60kg ha-1 N inorganic fertilizer + 1t ha-1 chicken dung, F3=30kg ha-1 N inorganic fertilizer + 1.5t ha-1 chicken dung, and F4=2t ha-1 chicken dung). Fertilization scheme significantly affected the days to flowering and maturity, vegetative tillers, plant height, number of productive and unproductive tillers, panicle length, herbage and grain yields of adlay and also the tiller and herbage yield of napier as well as the land equivalent and area time equivalent ratios. Fertilization with pure inorganic fertilizer or with combinations of chicken dung had ROI of 1.31 to 1.44 per peso invested.

Keywords: alternate staple, chicken dung, land equivalent ratio, versatile crop

Annals of Tropical Research 42(1):56-71(2020)

Genetic parameters of body weight in japanese quails (Coturnix japonica Temminck & Schlegel, 1849) in the Philippines

Author(s): Angie R. Poliquit1*


The establishment of breeding and selection programs to improve the genetic potential of poultry necessitates estimation of genetic parameters for different production and reproduction traits, Restricted maximum likelihood (REML) software was used to estimate the heritability (h2) and genetic correlations (r) of body weights in Japanese quails (C. japonica) from hatch to fifth week of age. A total of 224 Japanese quails composed of 56 males and 168 females arranged in a Completely Randomized Design (CRD) served as the base population. Body weight records, measured weekly from hatch to fifth week, were utilized to estimate the genetic parameters. Heritability estimates were 0.093±0.004, 0244±0.010, 0.031±0.001, 0082±0.004, 0325±0.016 and 0.025±0.001 for body weights at hatch (BW0), first week (BW1), second week (BW2), third week (BW3), fourth week (BW4) and fifth week (BW5), respectively. Low heritability estimates depict a decrease in additive genetic variance as the generations progressed. Negative genetic correlation was found between BW0 and BW4 (r=- 0.027). The significant positive genetic correlations of BW0 with BW1 (r=0.271); BW1 with BW2 (r=0.270), BW3 (r=0.294), BW4 (r=0.255), and BW5 (r=0.243); BW2 with BW3 (r=0.561), BW4 (r=0.649), and BW5 (r=0.503); BW3 with BW4 (r=0.726), and BW5 (r=0.551); and BW4 with BW5 (r=0.689) are expected to bring correlated responses in the other traits.

Keywords: Japanese quail, heritability, genetic correlation, body weight

Annals of Tropical Research 42(1):72-78(2020)

Nitrogen application improved the growth and yield performance of sweetpotato (lpomoea batatas (L.) Lam.)

Author(s): Flore-Anne C. Relente and Luz G. Asio1*


Nitrogen is one of the most critical nutrients affecting sweetpotato yield. This study was conducted to 1) evaluate the growth and yield response of sweetpotato NSIC SP 33 to different levels of N; and 2) determine the relationship between N level and root yield. A screenhouse experiment laid out in Completely Randomized Design (CRD) was carried out using five (5) N levels: 0, 40, 80, 120 and 160kg ha-1, each replicated thrice. Thetotal amount of N (as urea) was applied twice, one-half at planting and the other half at six weeks after planting (6 WAP) along with a blanket application of solophos and muriate of potash at 40 and 60kg ha-1 P2O5and K2O. An alluvial Umingan sandy loam soil (lnceptisol) was used as medium.
Levels of N significantly increased the leaf area, fresh herbage, total root yield, biomass, dry matter yield, shoot-root ratio, weight and number of marketable roots. Harvest index (HI) of plants applied with 40 and 80kg N ha-1 were comparable to those applied with 0 N. Increasing levels of N from 0 to 1 60kg ha-1 resulted in higher total crude protein (CP) and total N in the leaves. N uptake was higher in N-applied plants. Application of 40 and 80kg ha-1 N produced the highest root yield, above which root yield declined. Relationship between N level and root yield developed through regression analysis showed a quadratic function of Y=111.1794+1.2098x-0.00897x2 and R-square of 0.9904 which suggest that inherent soil N affected root development.

Keywords: regression analysis, quadratic function, storage roots, N fertilization, sweetpotato

Annals of Tropical Research 42(1):45-55(2020)

Effects of interaction between cowpea variety and the application of plant powders on Callosobruchus maculatus (Fabricius) (Coleoptera: Chrysomelidae) infestation of stored cowpea seeds

Author(s): Owolabi Moshood Azeez1, Adebola Adedoyin Osipitan2, Isaac Oludayo Daniel3 and Olufemi Olutoyin Richard Pitan2*


An integrated pest management scheme involving seed resistance and the application of powder of Cymbopogon citratus, Alstonia boonei, Hyptis suaveolens, Azadirachta indica, Loranthus braunii and Lycopersicum esculentum as protectant against the seed bettle, Callosobruchus maculatus (Fabricius), was evaluated in the laboratory at ambient temperature (29±3°C) and relative humidity (65±5%). Six resistant cowpea accessions selected from previous studies were treated with the six plant powders at 1.25% w/w in a 6×7 factorial arrangement fitted into a completely randomized design with five replicates. Seed treatment with any of the six plant powders on six accessions resulted in significantly higher adult mortality, lower oviposition rate, adult emergence inhibition, lower seed damage and higher seed germination over the control, Protection ability of the plant powders was influenced by the cowpea accessions used.

Keywords: cowpea resistance, accessions, botanicals, integrated Callosobruchus maculatus management

Annals of Tropical Research 42(1):33-44(2020)

Free radical scavenging activity of taro (Colocasia esculenta (L.) Schott) varieties with varying flesh color

Author(s): Erlinda A. Vasquez*, Precila D. Contero and Dilberto O. Ferraren


Corms of five taro varieties namelyz two NSIC-registered varieties, VG-1 (Kalpao) and VG-2 (Iniito), and three farmer’s variety, PRG 322 (Chowking), PRG 381 (Pandaga), and PRG 380 (Salot), were evaluated for antioxidant activity using 1, 1-diphenyl-2 picrylhydrazyl (DPPH) assay before and after cooking. The purple-fleshed varieties PRG 322, PRG 380 and VG-2 showed higher antioxidant activity than the yellow- and cream-fleshed varieties, The monomeric anthocyanin contents of PRG 380 and VG-1 PRG 322 and VG-2, which showed the highest free radical scavenging activity were measured using the pH differential method. The free-radical scavenging activity of the five taro varieties ranged from 134 to 154TEμm g-1 when raw and 127 to 147TEμm g-1 when cooked with the highest activity in raw PRG 322 followed by raw PRG 380 and VG-2. Cooked PRG 381 and VG-1 showed the lowest activity, Cooking reduced the activity by 4.5-10.2% with PRG 380 showing the highest reduction rate while the other four varieties did not vary significantly from 4.5-5.9%. Decreased in antioxidant activity can be due to the degradation and leaching out of antioxidant compounds during steamed cooking.

Keywords: taro, DPPH assay, anthocyanin, antioxidant, free radicals

Annals of Tropical Research 42(1):23-32(2020)

Management of acid sulfate soils under aerobic and anaerobic soil conditions revolves around organic matter and live plant macrophytes

Author(s): Patrick Michael1*


In acid sulfate soils (ASS), it is well established that sulfuric soil acidity is managed by application of a neutralising agent and sulfidic soil oxidation is prevented by water table management. This review summarizes recent studies using organic matter in amelioration of sulfuric soil acidity and curtailing of sulfidic soil oxidation by discussing the changes induced on soil pH, Eh and sulfate contents under varying soil moisture regimes. Increase in low pH, low Eh values and reduction in sulfate content have been observed in sulfuric and sulfidic soil following organic matter amendment under aerobic and anaerobic soil conditions. When organic matter co-existed with live plants, pH decreased with correspondingly high Eh values and high sulfate contents in almost all cases, even under anaerobic soil conditions. Practical consideration shows that application of organic matter by incorporation and spot application as surface mulch followed by establishment of plants under general soil use and management conditions create microniches conducive for root growth and negate the mechanisms that lead to severe acidification associated with live plants.

Keywords: Acid sulfate soils, organic matter, live plants, pH, redox potential, sulfate content

Annals of Tropical Research 42(1):1-22(2020)