No abstract

Native starch (NS) from different botanical origins (native rice/tapioca/oat starch, NRS/NTS/NOS) were hydrophobically modified by octenyl succinic anhydride (OSA), and the octenyl succinic (OS) groups were successfully introduced in the starch molecules which obtained OS-starch (OSRS, OSTS and OSOS) with different levels of modification (0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%) and degree of substitution (DS). The structural properties of the OS-starch, such as granule size, crystal, wettability and morphology were studied, and the OS-starch was used as particulate stabilizers to produce oil-in-water (O/W) Pickering emulsions. The emulsion index, droplet size distribution and microstructures of Pickering emulsions produced by different OS-starches were compared. OSA modification had almost no effect on the morphology or crystal structure types of three kinds of NS and OS-starch but markedly increased the contact angle and particle size distribution of OSRS, OSTS and OSOS. Esterification reaction of OSA and starch mainly occurred in amorphous regions of starch, and the OSA significantly improved the emulsifying capacity of OSRS, OSTS and OSOS granules and thus stabilized emulsions formed at higher levels (2.5% and 3.0%) of modification of OS-Starch exhibited better stability; the ability of OS-starch to stabilize Pickering emulsion was 3.0% OSRS > 3.0% OSOS > 3.0% OSTS, respectively. Observation and structural properties analysis of OS-starch granules and Pickering emulsion droplets showed that the number and thickness of the starch granules on the oil-water interface of the emulsion droplets increased with improvement of the OSA modification level, and an aggregation state was formed between the OS-starch granules, which was also enhanced with the OSA modification levels. These were all necessary for the Pickering emulsion stabilized by starch granules to remain in a steady state.

Strawberry (Fragaria x ananassa) is an economically and important fruit species that is grown extensively around the entire world. In this study, we obtained the complete chloroplast genome of F. x ananassa. The chloroplast genome of F. x ananassa is 155,529 bp in size, containing a large singlecopy region (85,523 bp), a small single-copy region (18,136 bp) and a pair of IR regions (each one of 25,935 bp). The overall GC contents of the chloroplast genome is 37.2%. The chloroplast genome of F. x ananassa contains 135 genes, including 90 protein-coding genes, 37 tRNA genes, and eight rRNA genes. The phylogenetic maximum-likelihood (ML) tree was constructed and based on 18 species plants and F. x ananassa chloroplast genomes, which F. x ananassa is closest related to Fragaria vesca subsp. vesca in phylogenetic relationship. This complete chloroplast genome can be further used for genomic studies, phylogenetic analyses, and genetic engineering studies of the genus Fragaria.