Judul: Evaluation Of Active Edible Coating From Chitosan Incorporated With Thai Herb Extract For Fresh-Cut Guava (Psidium Guajava L.)
Abstrak: Fresh-cut guava is one example of convenient novel foods that fit the many needs of modern lifestyle while it is also very perishable. Thai Herb extract might have antimicrobial activity as one of an alternative for prolonging shelf-life of fresh-cut product. Objectives of this research are study antimicrobial activity of Thai Herbs and application of active edible coating from chitosan incorporated with Thai Herb extract on fresh-cut guava (Psidium guajava L.) during storage. Screening of Thai Herbs, extracted with ethanol 50% and then dried with freeze drying method, for choosing the best one as an antimicrobial agent in edible coating was done by disk diffusion method. Total phenolic compound (TPC) and antioxidant capacity were analyzed using Folin-Ciocalteu method and DPPH scavenging activity respectively. Piper betle as selected Thai Herb extract had antimicrobial activity against Gram-positive and negative bacteria also yeast from 7.15±0.36 to 18.81±0.06 mm and TPC of 79.20±1.42 mg GAE/g sample also antioxidant activity of 674.59±1.48 μmol TE/g sample. The concentration of Piper betle extract used for formulation was determined according to minimum inhibitory concentration (MIC) with broth microdilution method and minimum bactericidal concentration (MBC). Highest MBC value was 12.5 mg/mL and concentration of extract used for coating solution was 25 mg/mL. Application of coating from chitosan incorporated with Piper betle extract for fresh-cut guava did not reduce amount of microbial growth until 6.37±0.21 log CFU/g at the end of storage and could not inhibit browning reaction as shown by L (62.28±4.45), a* (2.32±2.90), and b* (17.41±0.51) value. This coating process could not delay ripening process according to total titratable acidity (0.07±0.03 g citric acid/100 mL), total soluble solid (7.27±0.45°brix), and weight loss (0.12±0.01%). It also had the lowest hedonic score compared to control in sensory evaluation at day 8 for attributes of appearance (2.1±0.99), texture (3.9±1.73), aroma (2.9±1.37), and overall (2.8±1.23).
Keyword: chitosan, coating, fresh-cut guava, Piperaceae, Thai Herb

Judul: Storage of minimally processed crystal guava coated by glucomannan in modified atmosphere packaging
Abstrak: There had been many studies on minimally processed fruits in Indonesia, but none had been conducted on crystal guava. Research had also been done for edible coated minimally processed mango (Wuryani et al., 1999), and snake fruits (Rusmono et al., 1998) using soybean protein isolate as the major ingredient for the edible coating. The objective of this research was to observe the respiration rates, the quality changes, and the shelf life of edible coated minimally processed crystal guava using glucomannan as the major ingredient for edible coating. Preliminary experiment resulted in the selection of 1% glucomannan for the edible coating selection due to the lowest respiration of the edible coated minimally processed crystal guava stored at 5 oC. Storage temperature at three levels 5 oC, 10 oC, and temperature room, and atmosphere composition at also three levels 16-18% O2 and 3-5% CO2, 14-16% O2 and 3-5% CO2, 16-18% O2 and 5-7% CO2 were applied to the edible coated minimally processed crystal guava. The results indicated that storage temperature of 10 oC, and atmosphere composition of 14-16% O2 and 3-5% CO2 were favored compared to the room condition. The packaging films appropriate for the selected condition were stretch film and polypropylene film. Validation experiment used a packaging made of LDPE no.4 for the bottom container accommodating 166-277 g edible coated minimally processed crystal guava which were then covered by stretch film and polypropylene film. It was concluded that edible coated minimally processed crystal guava was best to be stored at 10 oC in a modified atmosphere packaging using stretch film with the ratio of weight to area 200 g/ 240 cm2 since it would be still accepted on the sixth day storage with an organoleptic score of 3.5 in the range of 1-5.
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Judul: Formulasi Hamiltonian untuk Menggambarkan Gerak Gelombang Soliter Dimensi Tiga di Permukaan Laut
Abstrak: Gelombang permukaan adalah gelombang yang terjadi perbedaan rapat massa antara air dan udara. Salah satu gelombang permukaan yang ditinjau adalah gelombang soliter. Formulasi gelombang soliter dilakukan dengan menggunakan formulasi Hamiltonian.
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