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Summary: The impacts of different cooking methods (boiling, steaming, baking, microwaving and frying) on chemical compositions, starch digestibility and antioxidant activity of taro corms were investigated. Compared with raw taro, boiling and frying reduced crude protein and ash contents. Frying significantly increased crude fat and fibre contents but decreased carbohydrate content. All cooking methods reduced oxalate content, especially frying. Among the cooked products, the boiled taro had the highest rapidly digestible starch (RDS) but the lowest resistant starch (RS) contents. In contrast, the fried taro provided the lowest RDS but the highest RS contents. All cooking methods reduced the total phenolic content and antioxidant activity of taro. The boiled taro had the lowest antioxidant activity but the fired taro provided the highest. Frying was able to retain most of the health‐promoting compounds with the lowest oxalate content; however, the high consumption of high‐fat fried taro may adversely affect human health. [ABSTRACT FROM AUTHOR]

Summary: This research aimed to study physicochemical properties and in vitro digestibility of flours and starches from taro cultivated in different regions of Thailand, that is, Kanchanaburi (KB), Chiang Mai (CM), Phetchaburi (PB) and Saraburi (SB). Taro starches were extracted from taro flours using either water or alkaline extraction. The taro flours had significantly (P ≤ 0.05) larger particle size, higher pasting and gelatinisation temperatures, and resistant starch content but lower total starch content, whiteness (L* value), paste viscosities and clarity than their corresponding extracted starches. All the taro starches exhibited polygonal and irregular granules and gave A‐type X‐ray diffraction pattern. The alkaline‐extracted taro starches had significantly (P ≤ 0.05) higher extraction yield, total starch content, L* value, pasting and gelatinisation temperatures, and paste clarity but lower granular size, amylose content, resistant starch content, paste viscosities and relative crystallinity than their water‐extracted counterparts. [ABSTRACT FROM AUTHOR]

Taro (Colocasia esculenta) starch is known to possess unique physical and functional properties such as low amylose content, A-crystalline form, small granules, higher swelling power, etc. Due to the presence of significant amount of calcium oxalate crystals, the food industry is reluctant to explore this unique and cheap starch source for various food applications. Traditional processes utilizing various physical and chemical methods to remove oxalate content of starch inevitably change its physical and functional properties. However, using oxalate oxidase can effectively remove oxalates without altering the unique properties of starch. Hence, an attempt was made to optimize oxalate oxidase assisted starch extraction process from taro flour using response surface methodology. A central composite design comprising 20 experimental trials with 10 cube points augmented with six axial points and four replicates at the center point was applied. A mathematical model was developed to show the effect of taro flour concentration, enzyme load and incubation time on the oxalate removal. Validity of the model was experimentally verified and found that 98.3% of total oxalates can be removed under optimal conditions. This is the first report of optimization of the production of starch from taro flour using microbial oxalate oxidase. [ABSTRACT FROM AUTHOR]

Cycadales is an extant group of seed plants occurring in subtropical and tropical regions comprising putatively three families and 10 genera. At least one complete plastid genome sequence has been reported for all of the 10 genera except Microcycas, making it an ideal plant group to conduct comprehensive plastome comparisons at the genus level. This article reports for the first time the plastid genome of Microcycas calocoma. The plastid genome has a length of 165,688 bp with 134 annotated genes including 86 protein-coding genes, 47 non-coding RNA genes (39 tRNA and eight rRNA) and one pseudogene. Using global sequence variation analysis, the results showed that all cycad genomes share highly similar genomic profiles indicating significant slow evolution and little variation. However, identity matrices coinciding with the inverted repeat regions showed fewer similarities indicating that higher polymorphic events occur at those sites. Conserved non-coding regions also appear to be more divergent whereas variations in the exons were less discernible indicating that the latter comprises more conserved sequences. Phylogenetic analysis using 81 concatenated protein-coding genes of chloroplast (cp) genomes, obtained using maximum likelihood and Bayesian inference with high support values (>70% ML and = 1.0 BPP), confirms that Microcycas is closest to Zamia and forms a monophyletic clade with Ceratozamia and Stangeria. While Stangeria joined the Neotropical cycads Ceratozamia, Zamia and Microcyas, Bowenia grouped with the Southern Hemisphere cycads Encephalartos, Lepidozamia and Macrozamia. All Cycas species formed a distinct clade separated from the other genera. Dioon, on the other hand, was outlying from the rest of Zamiaceae encompassing two major clades--the Southern Hemisphere cycads and the Neotropical cycads. Analysis of the whole cp genomes in phylogeny also supports that the previously recognized family--Stangeriaceae--which contained Bowenia and Stangeria, is not monophyletic. Thus, the cp genome topology obtained in our study is congruent with other molecular phylogenies recognizing only a two-family classification (Cycadaceae and Zamiaceae) within extant Cycadales. [ABSTRACT FROM AUTHOR]

The fatty acid profiles of the seed oils of four species from four plant families for which no or only sparse information on the fatty acid profiles is available are reported. The four seed oils are Garuga floribunda of the Burseraceae family, Ipomoea pes- caprae, of the Convolvulaceae family, Melanolepis multiglandulosa of the Euphorbiaceae family, and Premna odorata of the Labiatae (Lamiaceae) family. Linoleic acid is the most abundant in three seed oils, except I. pes- caprae in which oleic acid is most abundant. These two acids are overall the most abundant in all four seed oils studied. Of the four seed oils investigated, only G. floribunda contains minor amounts of a cyclic fatty acid (dihydrosterculic acid). [ABSTRACT FROM AUTHOR]

The fatty acid profiles of six seed oils of the Fabaceae (Leguminosae) family are reported and discussed. These are the seed oils of Centrosema pubescens, Clitoria ternatea, Crotalaria mucronata, Macroptilium lathyroides, Pachyrhizus erosus, and Senna alata. The most common fatty acid in the fatty acid profiles of these oils is linoleic acid with palmitic, stearic, oleic and linolenic acids usually completing the most prominent fatty acids in these species. Long-chain saturated fatty acids were observed in all oils. Centrosema pubescens and Macroptilium lathyroides exhibited the greatest amounts of long-chain saturated fatty acids exceeding the amount of stearic acid in these oils. C. pubescens exhibited slightly more that 6 % C24:0 together with some fatty acids >C25 and M. lathyroides approximately 4 % C22:0 and 3 % C24:0. The results are comparatively discussed to previous data on the fatty acid profiles of Fabaceae species. [ABSTRACT FROM AUTHOR]