Gaseous ozone at 13 parts per million (ppm) is applied repeatedly (10-30 cycles) to oxidize dry arrowroot starch. The ozonation increases carboxyl content of the starch by 0.13-0.52%. The starch granule surface becomes rougher and it exhibits a presence of fissure particularly at 30 cycles. Crystallinity decreases with the increase of ozonation cycle but the A-type pattern of the native starch remains unchanged. Swelling volume, solubility, water absorption capacity, and gel strength of the native starch increases following ozonation particularly at 30 cycles. Freeze-thaw stability is also augmented as indicated by a decrease in syneresis. The ozonation at 10, 20 and 30 cycles remarkably decreases the syneresis of native starch (5.24%) to 0.02%, 0.002% and 0.001% respectively. No effect of ozonation on pasting point is observed but an increase of values of the other pasting properties is noted. Regarding thermal properties, the ozonation increases T 0 of the arrowroot starch. The decrease in T, along with the increase in H of the ozonated starch, suggests that the ozonation leads to the formation of more homogenous and stronger crystallites. Overall, the effectiveness of gaseous ozonation at low concentration on modifying starch properties is dependent on the number of ozonation cycles.

Guava fruit is one of the most popular horticulture products because it has various health benefits. Once fruit is harvested, the fruit is still carrying out the respiration process during storage which results in changes in physical and chemical properties. One of chemical properties that is concerned by consumers is the total soluble solids, which explain the rough sugar content. The study examined the use of handheld near-infrared instruments to predict the total soluble solids of guava fruit at various storage periods rapidly and non-destructively. The research method used in this study was multivariate data analysis. Spectra pre-treatments were applied to correct the spectra and increase the accuracy of prediction. Calibration model was done by partial least squares regression (PLSR) and principal component regression (PCR). The results showed that the use of handheld near-infrared instrument was able to predict the total soluble solids of guava fruit with high accuracy. The best calibration model was produced by PLSR calibration method integrated with orthogonal signal correction (OSC) spectra pre-processing technique.

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Kusumiyati dkk.: Pengaruh waktu simpan terhadap nilai total padatan terlarut, kekerasan dan susut bobot buah mangga arumanis Kusumiyati • Farida • W. Sutari • J. S. Hamdani • S. Mubarok Pengaruh waktu simpan terhadap nilai total padatan terlarut, kekerasan dan susut bobot buah mangga arumanisThe effect of storage duration on total dissolved solids, firmness and weight loss of arumanis mango fruit Diterima : Abstract Arumanis mango is one of mango's leading commodities in Majalengka, West Java. Fruit sellers generally marketed mango fruit using bamboo wicker baskets mainly with the aim of making it easier for consumers to carry the fruit. In addition, the price of bamboo wicker basket is also cheap, hence the packaging of bamboo wicker basket is widely used by mango fruit sellers. During storage, mangoes experience changes in chemical and physical properties. These changes include the value of fruit firmness, total dissolved solids (TDS), and weight loss. The purposes of this study were to determine changes in firmness, TDS and weight loss at different storage duration using bamboo wicker baskets. The experimental design used in this research was a Completely Randomized Design (CRD) consisting of 3 treatments, which are 0 day, 7 days and 14 days storage duration with 10 replications. The numbers of samples used were 90 samples of arumanis mangoes. The results of this study indicated that there were changes in the value of firmness, TDS and weight loss in each treatment.

Use of shade on the cultivation of potato in medium altitude is expected to reduce both light intensity and temperature

Enhancement of productivity of potato plants grown on poor-P soil such as Inceptisols due to application of arbuscular mycorrhizal fungi (AMF) has been acknowledged. However, whether this AMF improved the quality of potato tubers is still need further investigation. This study was conducted to evaluate the effectiveness of AMF in enhancing potato quality and determine whether the addition of compost and biochar to soil can support the productivity of this biofertilizer in enhancing the nutrient content in the tubers of potato plant. Screen house experiment was set up in factorial design with treatments were organic matter types (compost and compost plus biochar), and application of arbuscular mycorrhiza (without and with AMF consisted of Glomus sp. and Gigaspora sp.). Results of experiment showed that there was no interaction effect between organic matter and AMF on quality of potato tubers, however, the individual treatment especially AMF  increased the content of protein and lipid of potato tubers. Biochar that added to soil with compost was also increased the lipid content of potato tubers. This finding showed that AMF application in potato production grown in poor P-soil was not only increased the yield of potato, but also increased the quality of potato tubers.

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