Category Archives: Volume 28 No. 1 (2006)

Production of acidophilus milk enriched with purees from colored sweetpotato (Ipomoea batatas Linn.) varieties


Author(s): Rodney H. Perez and Julie D. Tan

Abstract

Probiotic foods and drinks are becoming more popular nowadays. Probiotic foods are foods that contain health-promoting microorganisms. The beneficial effects of probiotics may be mediated by a direct antagonistic effect against specific groups of organisms, resulting in a decrease in their metabolism or by stimulation of immunity.
Acidophilus milk enriched with purees from kinampay and RC-2000 sweetpotato varieties was developed. Acidophilus milk is a probiotic drink, which is a product of milk fermentation by the bacteria Lactobacillus acidophilus. The fermented milk has been reported to have therapeutic value for suppressing toxin-producing organisms in the intestine of human.
The sugar level and product acceptability of the developed product was evaluated through sensory evaluation, and a proximate composition of the product was determined by proximate analysis.
It was found out that at 1% and 10% levels of inocula of the starter culture, the change in Total Titratable Acidity (TTA) of acidophilus milk was the same, hence, 1% inoculum was found practical in the production of acidophilus milk. Findings from previous experiments show that the maximum number of viable cells can be maintained

Keywords : acidophilus milk, probiotics, sweetpotato puree, fermented milk

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Filipino consumer preferences for peanut butter


Author(s): F. C. F. Galva1, L. S. Palomar2, M.L. dL. Francisco1, A. O. Lustre3 and A. V. A. Resurreccion4

Abstract

One-on-one interviews were conducted nationwide in different regions in the Philippines. A total of 387 households participated in the survey. Most households bought peanut butter at least once a month. Results indicated that sweetness, brand. and price of product were the major, factors that influenced the choice of Filipino consumers of peanut butter to bity. There was some indication of “brand loyalty”. Approximately two-thirds of Filipino families actually preferred the firm (stabilized) type of peanut butter even when they bought the flowing (not stabilized) type because of lower price of the latter. Color was not a major factor considered by Filipino consumers in buying peanut butter. Some consumers (50%) liked added flavor (chocolate or fruit jelly) in their peanut butter and were willing to pay more than PhP 1.00 additional price for it. Filipino consumers were aware and knowledgeable about vitamin A and the presence of vitamin A-fortified food products in the market. They indicated that they would buy vitamin A-fortified peanut products when these were made available. Most of them (>90%) were willing to pay more than PhP 0.25 additional price with a large proportion who were willing to pay more than PhP 1.00 additional price.

Keywords : consumers, food preference, vitamin A-fortified.

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Biochemistry of postharvest spoilage of sweet potato (Ipomoea batatas L.). 2. Comparison of cellulolytic enzyme production in cultures and fungi-infected sweet potato tubers


Author: R. C. Ray

Abstract

The study was conducted to determine the production in vitro and in vivo of cellulases by Botrydiplodia theobromae and Rhizopus oryzae. Isolates of these organisms were obtained from the postharvest decay of sweetpotato tubers.
Results revealed that B. theobrornae and R. oryzae which were isolated from postharvest spoilage of sweetpotato tubers produced endo-13-1,4-glucanase and exo-V-1 ,4-glucanase in culture and in fungi-infected tissues of sweetpotato tubers. The optimum temperature and pH for cellulose synthesis and activity were 30°C and pH 6.5, respectively.

Keywords : cellulose, fungi, spoilage, sweet potato

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Community structure of arthropods in Agusan del Norte lowland ricefields


Author(s): Rowena P. Varela11 and Lina T. Villacarlos2

Abstract

The structure of insect pests and natural enemies associated with white stern borer(Scirpophaga innonata Walker) in the irrigated and rainfed lowland ricefields in Agusan del Norte was studied for two cropping seasons. Sweep net method was used to sample the populations of the various arthropods. More species of arthropods were sampled in rainfed lowland ricefields than in irrigated ricefields, however, difference in the diversity was not significant. Number of species and populations of arthropods were affected by cropping husbandry practices particularly weeding and application of pesticides. Climate did not significantly affect the arthropod diversity due to the erratic climatic conditions at the onset of the El Niño phenomenon.

Keywords : community structure, arthropods, lowland rice fields

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Nitrate concentrations in animal manure dumping sites


Author(s): Marilyn C. Sebial1 and L. S. Sonon1,2

Abstract

This study aimed to characterize the chemical and physical properties of soil, and measure the nitrate concentrations at varying soil depths in the manure disposal sites of the Leyte State University piggery and beef cattle projects. Soil chemical analysis revealed that organic matter in both the piggery and beef cattle areas were concentrated in the upper 20 cm and gradually decreased with depth. A similar trend was observed for total N where the 0-20 cm depth contained approximately 0.30% N and this level decreased in the deeper soil layers, The soil in the piggery area was slightly acidic (pH 5.30) while that in the cattle area was near neutral (pH 6.50). The entire soil profile in both sites was generally highest in nitrate at the surface and decreased with depth. Nitrate concentrations were relatively higher when there were more animals in the project site. Solution samples from 120 cm lysimeters yielded high levels of nitrate (about 200 mg L-1), an indication that this ion was being moved to greater soil depths.

Keywords : soil nitrate concentrations, animal manures, dump sites

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Soil biological activity under different land-uses in Leyte, Philippines


Author(s): Carsten Marohn1, Reinhold Jahn2 and Joachim Sauerbornl1

Abstract

On seven sites in Western Leyte, Philippines, different land-uses, namely reforestation with indigenous tree species (`rainforestation`), reforestation with exotic tree specie Gmelina arborea, and traditional fallow / grassland use were compared with respect to soil biological activity. Analysed parameters were Basal Respiration (BR), microbial carbon (Substrate-Induced Respiration method, SIR) and leaf litter decomposition. Correlations between BR, SIR, metabolic quotient (qCO2), soil organic carbon (Corg) soil N (NT) and pH were assessed. BR and Cmic, SIR as well as the metabolic quotient qCO2 (BR/SIR) proved to be sensitive parameters and the methods gave reproducible values to distinguish sites and land-uses in most cases. However, due to differences among fallow /grassland treatments, a uniform tendency between these and rainforestation was not observed. On the other hand, BR and Cmic SIR were significantly higher under Gmelina than under either of the other land-uses. Correlations between parameters were strongest for BR vs. Corg, and BR vs. pH as well as for Cmic SIR vs. Corg and qCO2 vs. Corg

Keywords : soil biological activity; basal respiration; Substrate-Induced Respiration; land-use; reforestation.

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