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Buckwheat is an important starch source because of its health benefits. In this study, buckwheat starches isolated from 12 varieties were analyzed based on the morphological, structural and physicochemical properties. The results showed that starch samples from different varieties had high purity with the total starch ranging from 91.29 to 95.11%, while showing significant differences in ash content (0.12-0.25%), protein content (0.26-0.34%) and amylose content (29.55-36.13%), respectively. All samples presented spherical and irregular shapes and typical A-type crystalline structure, but obvious differences in granule size distribution and relative crystallinity (26.37-35.21%) were observed among 12 varieties. Starch samples differed in lamellar structures, showing higher values of thickness of the samples with higher amylose content. In addition, buckwheat starches with higher amylose content showed higher values in light transmittance and rheological properties, while starch samples with lower amylose content obtained higher values in terms of water solubility, swelling power, pasting behaviors and thermal parameters. The principal component analysis and cluster analysis based on starch property parameters indicated that there were significant similarities and differences among 12 varieties, which might be related to the genotypes. This study would provide valuable information for the full use of buckwheat starch in food and non-food industries.

In insects, the identity of body segments is controlled by homeotic genes and the knockdown of these genes during embryogenesis can lead to an abnormal development and/or atypical phenotypes. The main goal of this study was to investigate the involvement of labial (lab), deformed (dfd), sex comb reduced (scr), extradenticle (exd) and proboscipedia (pb) in rostrum development in the Neotropical brown stink bug Euschistus heros, using parental RNAi (pRNAi). To achieve this objective, 10-days-old adult females were first microinjected with double-stranded RNAs (dsRNA) targeting these five genes. Then, the number of eggs laid per female, the percentage of hatched nymphs with normal or abnormal phenotype and target gene silencing were evaluated. Except for the dsDfd-treatment, the number of eggs laid per female per day was not affected by the different dsRNA-treatments compared to the control (dsGFP). However, treatment with either dsLab, dsDfd, dsScr or dsExd caused a strong reduction in egg hatching. The dsExd-treatment caused no apparent change in phenotype in the nymphs while hatched nymphs from the dsDfd, dsScr and dsPb-treatment showed abnormalities in the rostrum. Particularly for the dsPb-treatment, 91% of the offspring displayed a bifurcated rostrum with a leg-like structure. Overall, these results indicate that these five genes are involved in E. heros embryonic development and that the knockdown of dfd, scr and pb leads to an abnormal development of the rostrum. Additionally, this study demonstrates the efficiency of pRNAi in studying genes involved in embryogenesis in E. heros, with clear phenotypes and a strong target gene silencing in the next generation, after treatment of the parent female adult with gene-specific dsRNA.

We report the fabrication of multiple emulsions where both the enclosed and the external water phases are structured using a combination of two non-gelling biopolymers. Emulsions (with gelled inner water droplets and gelled water continuous phase) were created using a simple ‘one-step’ process where the oil phase (triglyceride oil and polyglycerol polyricinoleate) and the water phase (containing a combination of locust bean gum and carrageenan) were emulsified at an elevated temperature (70 °C) followed by cooling to room temperature. The temperature triggered gelling of the synergistic biopolymer combination led to the formation of structured emulsions on cooling. Flowable to self-standing emulsion gels could be prepared by changing the total concentration of polymers (and the ratios of the individual polymers) as confirmed from low amplitude oscillatory shear rheology and creep recovery measurements. The cryo-scanning electron microscopy images of freeze-fractured emulsion samples revealed the presence of gelled inner water droplets. Further, when subjected to heating and cooling cycles, emulsions displayed reversible rheological changes which could be tuned by simply changing the total polymer concentration and the proportions of individual polymers. Such biopolymer-based structured emulsions with interesting microstructure and rheological properties could find potential applications in bio-related fields like food structuring.

Physical trapping of a hydrophobic liquid oil in a matrix of water-soluble biopolymers was achieved using a facile two-step process by first formulating a surfactant-free oil-in-water emulsion stabilized by biopolymers (a protein and a polysaccharide) followed by complete removal of the water phase (by either high- or low-temperature drying of the emulsion) resulting in structured solid systems containing a high concentration of liquid oil (above 97 wt %). The microstructure of these systems was revealed by confocal and cryo-scanning electron microscopy, and the effect of biopolymer concentrations on the consistency of emulsions as well as the dried product was evaluated using a combination of small-amplitude oscillatory shear rheometry and large deformation fracture studies. The oleogel prepared by shearing the dried product showed a high gel strength as well as a certain degree of thixotropic recovery even at high temperatures. Moreover, the reversibility of the process was demonstrated by shearing the dried product in the presence of water to obtain reconstituted emulsions with rheological properties comparable to those of the fresh emulsion.

The preparation and characterization of oleogels structured by using a combination of a surface-active and a non-surface-active polysaccharide through an emulsion-templated approach is reported. Specifically, the oleogels were prepared by first formulating a concentrated oil-in-water emulsion, stabilized with a combination of cellulose derivatives and xanthan gum, followed by the selective evaporation of the continuous water phase to drive the network formation, resulting in an oleogel with a unique microstructure and interesting rheological properties, including a high gel strength, G′>4000 Pa, shear sensitivity, good thixotropic recovery, and good thermostability.

White-flesh (Hylocereus undatus; WF) and red-flesh (Hylocereus polyrhizus; RF) dragon fruit purees were subjected to a heat treatment for 0 to 60 min at temperatures between 50 and 90 °C. The influence of the different heat treatments on the physicochemical properties, colour, betacyanins content, microbial destruction, antioxidative properties and rheological parameters were investigated. The physicochemical values and antioxidative properties of the unheated RF were significantly higher than that of the unheated WF (p 0.7733) and TCC of RF can be used to predict the betacyanins content (R2 = 0.9442). The antioxidative properties of the heated WF and RF increased with heating treatment. The linear correlation among the antioxidative properties was strong (R2 > 0.8587). WF and RF showed shear thinning behaviour. After heating, the apparent viscosity of WF and RF increased and all cases fitted very well with the power law model (R2 > 0.9988). Thus, the heated dragon fruit purees, particularly the RF, offer possibilities to be applied in foodstuffs due to their interesting physicochemical properties and nutritional attributes after thermal treatment.

This study investigated die effect of storage temperature on triacylglycerol (TAG) migration, visual fat bloom and taste of industrially produced milk chocolates with a hazelnut-based filling. The chocolates were stored for up to 10 months at 18 degrees C, either directly after production or with the inclusion of a variable time at -20 or 4 degrees C immediately after production and prior to further storage at 18 degrees C. TAG migration from the filling through the chocolate shell was quantified by HPLC analysis of chocolate sampled from the chocolates' surface. Both [OOO/SOS] and [LOO/SOS] were used as markers for oil migration. Compared to storage at 18 degrees C only, chilling or freezing of the chocolates for part of the storage time was found to reduce the amount of TAG migration. Effects on diffusion, capillary transport and TAG immobilization during the thermal treatment can be raised as possible reasons for this decrease. Furthermore storage at -20 degrees C decreased oil migration during subsequent storage at 18 degrees C. This suggests a crystallization effect during the storage at -20 degrees C, leading to permanent (micro) structural changes. Although a thermal treatment at 4 degrees C compared to -20 degrees C was less effective in retarding TAG migration, storage at low positive temperatures immediately after production appears already beneficial in the prevention of visual fat bloom. Adverse effects of the thermal treatments on the chocolates' taste were not observed.