Enhanced gelling property and freeze-thaw stability of potato, tapioca and corn starches modified by mild heating in aqueous ethanol solution.

BACKGROUND: Physically modified starches can be classified as natural ingredients on food labels and clean label products. Thus, the market demand for physically modified starch is increasing. Potato, tapioca and corn starches were physically modified by mild heat treatment in an alcoholic solution to enhance their gelling property and freeze-thaw stability. RESULTS: During mild heating of starch suspension (40% w/w) in 10% ethanol solution at the onset gelatinization temperature, granular swelling of starch occurred, followed by amylose leaching with medication of the surface structure of the starch granules. All treated starches exhibited increased gelatinization and pasting temperatures and decreased breakdown for pasting as a result of improved stability against shear and heat. The treated starches had higher hardness, cohesiveness and springiness of gel than the respective native starches, and these gel properties were more pronounced in potato starch than in tapioca and corn starches. The treated starches showed substantially reduced gel syneresis during freeze-thawing. CONCLUSION: Physical modification of starch by mild heat treatment in an alcoholic solution substantially improved its gelation ability and freeze-thaw stability. © 2024 Society of Chemical Industry.

CML10, a variant of calmodulin, modulates ascorbic acid synthesis.

Calmodulins (CaMs) regulate numerous Ca(2+) -mediated cellular processes in plants by interacting with their respective downstream effectors. Due to the limited number of CaMs, other calcium sensors modulate the regulation of Ca(2+) -mediated cellular processes that are not managed by CaMs. Of 50 CaM-like (CML) proteins identified in Arabidopsis thaliana, we characterized the function of CML10. Yeast two-hybrid screening revealed phosphomannomutase (PMM) as a putative interaction partner of CML10. In vitro and in vivo interaction assays were performed to analyze the interaction mechanisms of CML10 and PMM. PMM activity and the phenotypes of cml10 knock-down mutants were studied to elucidate the role(s) of the CML10-PMM interaction. PMM interacted specifically with CML10 in the presence of Ca(2+) through its multiple interaction motifs. This interaction promoted the activity of PMM. The phenotypes of cml10 knock-down mutants were more sensitive to stress conditions than wild-type plants, corresponding with the fact that PMM is an enzyme which modulates the biosynthesis of ascorbic acid, an antioxidant. The results of this research demonstrate that a calcium sensor, CML10, which is an evolutionary variant of CaM, modulates the stress responses in Arabidopsis by regulating ascorbic acid production.

Preparation of catechin-starch nanoparticles composites and its application as a Pickering emulsion stabilizer.

Starch is a biopolymer commonly used for nanoparticle synthesis. Starch nanoparticles (SNPs) have potential as encapsulation agents and Pickering emulsion stabilizers. Here, we prepared SNPs by dry heating under mildly acidic conditions to encapsulate catechin. Catechin (30 mg) and SNPs (50-150 mg) were dispersed in distilled water and freeze-dried to prepare catechin-SNP composites. Isothermal titration calorimetry and Fourier-transform infrared spectroscopy revealed that the binding of catechin to SNP may involve spontaneous hydrogen bonding and hydrophobic interactions. SNPs exhibited encapsulation efficiency for catechin, with 100 % catechin retention when 150 mg of SNP was used to prepare the composites. The catechin-SNP composites had a particle size of 54.2-74.9 nm. X-ray diffraction analysis revealed the formation of small amounts of inclusion complexes in catechin-SNP composites. As the amount of SNPs added for encapsulation increased, the catechin encapsulated in the SNP composites exhibited higher water solubility and UV stability than the pure catechin. The catechin-SNP composite with 150 mg of catechin exhibited the highest contact angle (51.37°) and formed a stable emulsion without notable droplet size changes. Therefore, catechin-SNP composites improved the encapsulation efficiency, water-solubility, stability of catechins, and Pickering emulsion stability.

Improvement of textural and sensory characteristics of aged rice using hydrothermal treatment with xanthan gum.

Aged rice (AR) was mildly heated in aqueous dispersions containing different amounts of xanthan gum (Xan) at 60 °C for 1 h, and then dried in a humidity chamber (50 °C, 80% RH) for 12 h. The AR kernels treated without Xan showed a coarse surface with many pores after cooking, whereas the same rice treated with Xan showed a smooth and uniform surface. Prior to the treatment, the cooked AR was harder and less sticky than the cooked fresh rice (FR). The hydrothermal treatment softened the cooked AR although did not change its adhesiveness. The same treatment in the presence of Xan could increase the adhesiveness of AR, making the textural characteristics of AR similar to those of FR. Sensory evaluation revealed that the mild heat treatment in the presence of Xan restored the eating quality and acceptability of cooked AR which had been lost by aging. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-023-01306-0.

Effects of germination and roasting on physicochemical and sensory characteristics of brown rice for tea infusion.

Germinated brown rice was roasted for the preparation of tea. The germination induced substantial increases in reducing sugars (from 3224.06 to 5028.80 mg/100 g), free amino acids (from 62.51 to 165.07 mg/100 g), volatile compounds, and phenolics (10.06 to 14.27 mg GAE/100 g). Roasting decreased the residual contents of free amino acids and reducing sugars, but produced the volatiles and phenolics. Browning index was slightly decreased by the germination (from 22.69 to 20.13), but significantly increased by the subsequent roasting. The germinated BR (GBR) was more susceptible to roasting than native BR. Acrylamide content in the roasted GBR was significantly lower than that in the roasted BR, because of the lower asparagine content in GBR. Sensory evaluation revealed that a mild roasting for 5 min at 230 °C after germination for 2 days was appropriate to produce a brown rice tea.

Improvement of mechanical properties of orodispersible hyaluronic acid film by carboxymethyl cellulose addition.

Orodispersible films (ODF) were prepared with mixtures of hyaluronic acid (HA) and carboxymethyl cellulose (CMC), and the effect of CMC addition on the disintegration and mechanical properties of the composite films were examined. Low molecular weight HA (10 kDa) appeared more acceptable for ODF than high molecular weight HA (800 kDa) because of its rapid disintegration in the oral cavity. The composite films appeared similar to pullulan film with excellent transparency and surface smoothness. The disintegration time as well as mechanical properties of the films such as tensile strength and elongation at break were increased by the addition of CMC. Overall, the CMC addition, up to 35%, improved the mechanical properties of low molecular weight HA film within a proper range of disintegration time for ODF.

Changes in phenolic acid composition and associated enzyme activity in shoot and kernel fractions of brown rice during germination.

Phenolic acid composition and activities of two associated enzymes such as PAL (phenylalanine ammonia-lyase) and CW-PRX (cell wall peroxidase) in brown rice (BR) were examined during a germination for 4 days. Shoot and kernel fractions of the germinated brown rice were separated, and soluble extracts and insoluble residues of the fractions were analyzed. In the shoot fraction, the PAL activity and soluble phenolic acid content reached to its maximum on the second day of atmospheric germination, and decreased thereafter. In contrast, the amount of insoluble phenolic acids and CW-PRX activity continuously increased during the germination for 4 days. Comparing the shoot fractions, the kernel fraction exhibited lower activities of PAL and CW-PRX, but showed an increase in total phenolic acid content during germination. Germination raised the antioxidant activity of brown rice, especially in the shoot fraction which contained more phenolic acids than the kernel fraction.

Germinated brown rice and its bio-functional compounds.

Brown rice (BR) contains bran layers and embryo, where a variety of nutritional and biofunctional components, such as dietary fibers, γ-oryzanol, vitamins, and minerals, exist. However, BR is consumed less than white rice because it has an inferior eating texture when cooked. Germination is one of the techniques used to improve the texture of the cooked BR. In addition, it induces numerous changes in the composition and chemical structure of the bioactive components. Moreover, many studies reported that the germination could induce the formation of new bioactive compounds, such as gamma-aminobutyric acid (GABA). The consumption of germinated brown rice (GBR) is increasing in many Asian countries because of its improved eating quality and potential health-promoting functions. However, there is still a lack of studies on the compositional and functional changes of the bioactive components during germination. This review contains recent research findings, especially on the bioactive components in GBR.