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Giant swamp taro (GST, Cyrtosperma merkusii) is an underutilized tropical endemic crop of North Sulawesi. GST starch has the potential to be utilized in various food products such as dry noodles, artificial rice, bioplastic and various other applications. This study aimed to determine the effect of acid modification on the physico-chemical properties of GST starch. Starch was extracted from GST corms by maceration in 2% sodium chloride solution. GST starch was modified by acid hydrolysis using 0.2 M citric acid solution, followed by neutralization in 1 M sodium hydroxide solution. The starch samples (native and modified) were analysed for the following physicochemical parameters; pasting properties, viscosity, total starch content, swelling power. The Fourier transform infrared (FTIR) spectroscopic analysis and Field emission scanning electron microscopy (FESEM) of the starch were also carried out. The results revealed that acid modification of GST starch has significant effect on its physico-chemical properties, microstructure and FTIR spectrum. Native GST starch had high amylose and amylopectin contents with a high ratio of amylopectin to amylose. Acid modification of the GST starch resulted in a starch with lower amylose and amylopectin content. Consequently, lowering the viscosity and gelling properties of the starch. Therefore, modification of GST starch by acid hydrolysis could result in starch product with better physic-chemical properties that could be employed as food thickeners. However, for applications where a more stable and stronger gel matrix is required, other modification methods such as the cross-linking and heat moisture treatment (HMT) methods should be considered. [ABSTRACT FROM AUTHOR]

Growing recognition of the potential vulnerabilities of major crop systems has spurred a growing interest in the potential of alternative crops which may be resilient to climate change and also help mitigate its effects. In Indonesia, such issues are particularly pertinent given that country's particular vulnerability to climate change impacts high dependence on agricultural livelihoods and varied topographies and growing conditions. Cyrtosperma merkusii (giant swamp taro) is a wetland plant which has historically formed part of food systems in the eastern Pacific. The plant has the potential to be cultivated as a source of starch on marginal coastal land and on peatlands with high water tables. The aim of this paper was therefore to determine site conditions that promote growth of C. merkusii and the macro and micronutrient status of the corms. Naturally, the size of the plants varied substantially among sites, with a neutral pH, and low redox and conductivity being strong edaphic predictors of corm size. Despite substantial differences in the soil properties of the different study sites, there were no significant differences in the macro and micronutrient content of the corms. Field trials showed that although the plants grew under dry land conditions, the plants grew bigger and yielded corms with greater concentrations of Fe, Mn and K under waterlogged conditions, indicating that a high‐water table is the best cultivation environment for C. merkusii. The nutrient content of the corms suggests that, although primarily a starch crop, C. merkusii could also increase the intake of Fe in populations where Fe deficiency is pervasive. We conclude that the wetland plant C. merkusii has considerable potential as a paludiculture crop in low‐lying areas of SE Asia as it was tolerant of a wide range of soil conditions and performed well when cultivated under waterlogged conditions without additional fertilisation. [ABSTRACT FROM AUTHOR]