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THE POSSIBILITY OF CONTROLLING SCLEROTIUM ROLFSII ON SOYBEAN (GLYCINE MAX) USING TRICHODERMA AND TEBUCONAZOLE*) DHARMAPUTRA, OKKY S.
BIOTROPIA No. 7 (1994)
Publisher : SEAMEO BIOTROP

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11598/btb.1994.0.7.113

Abstract

The possibility of controlling S. rolfsii on soybean (Glycine max) var. Rinjani using T. aureoviride and Tebuconazole under field conditions was studied. The experiment was conducted at the experimental plot of SEAMEO BIOTROP. The pathogen was mixed with the soil (2 kg/plot) 4 days before the inoculation of the antagonist (2.25 kg/plot). The measurement of each plot was 2.5 x 6 m2 . N, P and K (120 kg/ha) were applied at the same day with the inoculation of the pathogen. Soybean seeds were planted 7 days after the inoculation of the antagonist. The distance between plants and between plots were 20 and 40 cm, respectively. The fungicide at concentration of 100 g/ha (in vitro concentration) and 210 g/ha (field or recommended concentration) were applied using 2 methods, i.e. 1) spraying on the planting hole at the same day as the planting of soybean seeds, and 2) spraying on the soil surrounding the plants 7 days after planting. Soils that were neither inoculated with the antagonist nor the fungicide were used as controls. Three replications (3 plots) were used for each treatment (including the control). The results showed that the inoculation of the antagonist, the concentrations of the fungicide, and time of application gave very significant differences in the percentages of the plants infected by the pathogen and significant differences in seed production; while the interaction between the inoculation of the antagonist and the concentrations of the fungicide, between the concentrations of the fungicide and the time of application, and between the inoculation of the antagonist, the concentrations of the fungicide and the time of application did not give significant differences either in the percentages of the plants infected by the pathogen or seed production. The percentage of plants infected by the pathogen was lower on soil inoculated with the antagonist (31.6%) than on soil not inoculated with the antagonist (52.9%). The percentage of plants infected by the pathogen was lower on soil treated with the fungicide either at in vitro concentration (37.5%) or at field concentration (37.4%) than on the soil not treated
ASSESSMENT OF THE QUALITY OF ARABICA COFFEE BEANS FROM THREE PROCESSING METHODS AND TWO TYPES OF PACKAGING MATERIALS Dharmaputra, Okky S.; Ambarwati, Santi; Retnowati, Ina; Nurfadila, Nijma
BIOTROPIA Vol. 28 No. 3 (2021): BIOTROPIA Vol. 28 No. 3 December 2021
Publisher : SEAMEO BIOTROP

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11598/btb.2021.28.3.1325

Abstract

In Southeast Asia, Indonesia is the second highest-producing country of coffee beans after Vietnam. Consequently, Indonesia competes with other countries in producing good quality coffee beans. However, not many people have sufficient skills in tackling problems related to the postharvest handling of these coffee beans. The objective of this study was to assess the quality of Arabica coffee (Coffea arabica) beans in terms of moisture content, fungal infection (especially ochratoxin A or OTA producing fungi), OTA contamination, and the taste of the coffee during storage. The three processing methods used were dry, wet, and semi-wet methods. The beans were packed using two types of packaging materials, i.e. Kantong Semar high gas barrier and polypropylene bags (4 kg/bag). They were then stored under warehouse conditions during 4 months of storage. The moisture content of coffee beans processed using the three methods and packed using polypropylene bags was higher than that of coffee beans packed using Kantong Semar high gas barrier; however, it was still lower than the safe moisture content for coffee determined by the Indonesian National Standard (12.5%). Aspergillus niger was found in coffee processed using the three methods and packed using a Kantong Semar high gas barrier. Its population was relatively low (< 0.1 x 10 cfu/g wet basis). Aspergillus ochraceus was found in coffee processed using dry and wet methods at the beginning of storage. Its population was also relatively low (< 0.3 x 10 cfu/g w.b. OTA content was not detected in all coffee samples, because it was lower than the detection limit of the instrument used (< 1.85 ppb). At the beginning of the storage, all coffee samples were dominated by yeast with the population of 1.9 x 102 – 1.2 x 103 cfu/g w.b. The taste of coffee in various treatments during 4 months of storage was still above the total standard score for specialty grade ≥ 80. The highest total score (84) was found in coffee beans processed using a dry method and packed in Kantong Semar high gas barrier. The three processing methods and the two types of packaging materials can be used to maintain the quality of coffee beans during 4 months of storage.
FUNGAL INFECTION AND AFLATOXIN CONTAMINATION IN STORED NUTMEG (Myristica fragrans) KERNELS AT VARIOUS STAGES OF DELIVERY CHAIN IN NORTH SULAWESI PROVINCE Dharmaputra, Okky S.; Ambarwati, Santi; Retnowati, Ina; Nurfadila, Nijma
BIOTROPIA Vol. 22 No. 2 (2015): BIOTROPIA Vol. 22 No. 2 December 2015
Publisher : SEAMEO BIOTROP

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (252.677 KB) | DOI: 10.11598/btb.2015.22.2.458

Abstract

Fragrant nutmeg (Myristica fragrans) is an important commodity widely used in food and pharmaceutical industries; therefore, its quality should be strictly monitored. The objectives of this research were to: (a) investigate the occurrence of fungi, including the presence of A. flavus and aflatoxin contamination in stored nutmeg kernels; (b) measure moisture content and percentage of damaged kernels; and (c) evaluate nutmeg kernels along the delivery chain. This study consisted of surveys, interviews, and sample collection along the delivery chain. The research was conducted in April–May 2013 in three regencies (North Minahasa, Siau Tagulandang Biaro (Sitaro), and Sangihe Talaud) and two cities (Bitung and Manado). A total of 76 nutmeg kernel samples were collected: 25 from farmers, 22 from collectors, and 29 from exporters. Results showed that the moisture content of nutmeg kernels collected from the North Sulawesi Province did not exceed the maximum moisture content limit set by the Indonesian National Standard (SNI), which is 10%. However, nutmeg kernels collected from farmers and collectors had a high percentage of physical damage. Aspergillus niger and Endomyces fibuliger were the dominant fungi found in samples from farmers and collectors, whereas Eurotium repens was predominantly associated with samples stored by exporters. Levels of aflatoxin B₁ and total aflatoxin in several samples collected from farmers and exporters were relatively high. A non-parametric statistical analysis showed that the delivery chain did not have a significant effect on moisture content, percentage of damaged kernels, total fungal population, or total aflatoxin content. This study suggests that improvements in postharvest handling practices performed by farmers, collectors, and exporters in North Sulawesi Province (North Minahasa, Sitaro, and Sangihe Talaud), Bitung, and Manado are necessary to minimize contamination of aflatoxin B₁ and total aflatoxin.
POTENCY OF YEAST AS A BIOCONTROL AGENT OF OCHRATOXIN A-PRODUCING FUNGI AND ITS EFFECT ON ARABICA COFFEE TASTE Dharmaputra, Okky S.; Retnowati, Ina; Nurfadila, Nijma
BIOTROPIA Vol. 30 No. 1 (2023): BIOTROPIA Vol. 30 No. 1 April 2023
Publisher : SEAMEO BIOTROP

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11598/btb.2023.30.1.1379

Abstract

Biocontrol agents can be used to control mycotoxigenic fungi, which include different species of yeast. The objectives of this research were to select yeast isolates that can inhibit the growth of ochratoxin A (OTA)-producing fungi (Aspergillus ochraceus BIO 37310) and to increase the taste of Arabica coffee processed using wet and semi-wet methods. Twenty-two yeast isolates (KA, KA2, KB, KB2, KC, KD, Endomyces decipiens BIO 131215, E. fibuliger BIO 132216, BIO 132217, BIO 13218, BIO 132219, BIO 132220, Candida krusei (= Issatchenkia orientalis) BIO 211285, BIO 211286, BIO 211287, BIO 211288, BIO 211289, BIO 211290, BIO 211291, Saccharomyces cerevisiae BIO 341363, BIO 341364, and BIO 341365) were screened for their antagonistic property against A. ochraceus BIO 37310 in vitro using well (dip) test method. The results showed that C. krusei (BIO 211287, BIO 211288, and BIO 211289) inhibited A. ochraceus BIO 37310. In vivo the highest yeast population was found in coffee beans processed using a semi-wet method inoculated with C. krusei BIO 211288 (46,222 ± 9,576 cfu/g), which was not significantly different from that of the coffee beans inoculated with C. krusei BIO 211287 (36,333 ± 14,000 cfu/g). The three yeast isolates were also able to grow either in coffee beans processed using wet or semi-wet methods inoculated with A. ochraceus BIO 37310 and each yeast isolate. Interaction between the three yeast isolates and A. ochraceus BIO 37310 resulted in E-type interaction, i.e. the fungus was not able to grow anymore, while the yeasts grew further. The total cupping scores of coffee beans inoculated with the three yeast isolates were higher than those of coffee beans uninoculated and inoculated with commercial lactic acid bacteria. The three yeast isolates could be used as biocontrol agents of A. ochraceus BIO 37310 and increase the sensorial quality of coffee beverages.