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This study aimed to design an accurate and practical system of leaf area determination using a smartphone. A software application for leaf area computation was developed using Open CV (Open Source Computer Vision) library. Open CV software was tested to estimate the accuracy of leaf area calculation. Leaf area calculations were undertaken using three different image resolutions to compare their accuracy. The results of the software calculations were then compared with the results of the laboratory leaf area meter to identify any errors. The results showed that higher image resolutions improved accuracy by reducing errors. High resolution image gave higher accuracy, however processing speed decreased. Leaf measurement in this project resulted in accuracy range between 92.8% to 99.0%. It was concluded that the Open CV algorithm gave fast and adequate accuracy for leaf area calculation, and that the smartphone mobile application system was practical for field use.

Indonesia is one of the major countries which contributes the world’s guava production. Guava var. Getas Merah is commonly found in Indonesia. Guava has a short shelf-life as it rapidly goes under postharvest ripening. This leads to a faster deterioration of physicochemical and sensorial properties of guava. A generally used method to extends shelf-life is by edible coating. In this study, a combination of alginate and Cyclea barbata leaves powder (CBLP) was investigated as a potential edible coating. The analysis of firmness, total soluble solids, total reducing sugar, total titratable acidity and organoleptic tests were conducted to evaluate the quality of guava fruits stored for 20 d at 14°C. A split plot design study was used and four different treatments with different CBLP concentrations were applied. The samples treated with 2% alginate and 0.8% CBLP showed the lowest total dissolved solids, total reducing sugar, and total titratable acidity. Moreover, the samples were reported with the highest score on color, taste, and texture parameters. The firmness test showed that samples treated with 2% alginate and 0.2% CBLP had the lowest firmness loss and highest score for aroma. In summary longer quality retention of guava fruits was found after the addition of CBLP in alginate-based edible coating.

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Cutting treatment on fresh-cut apple could lead to browning incident in fruit. Several chemicals could be used as an antibrowning agent. In this study, we compared several antibrowning agents in fresh-cut Apple cv Manalagi. This study was carried out in a single factor experimental design and arranged in completely randomized design (CRD) consisting of four treatments: 100 mmol L-Arginine, 150 ppm Citric Acid, 150 ppm Ascorbic Acid, 50 ppm Natrium metabisulfite, and control with no treatment. The result showed that Sodium metabisulfite and L-Arginine treatment significantly could inhibit browning in fresh-cut Apple cv Manalagi on day 10. L-arginine also showed a high overall score in panelist preferences in sensory test. Further study could explore on L-arginine potential as antibrowning agent for other fresh-cut fruit and vegetables.