Search

The content and composition of rice kernels are closely related to the textural properties of cooked rice. In this study, the mechanistic explanations of textural changes were linked to proton mobility, leaching behavior, and the molecular features of rice components during cooking. The decreasing trend of hardness and the formation of stickiness was mainly determined by the molecular mobility of components. The molecular weight (Mw) of starch and protein in leached solids increased with the leaching at 70-100 °C. The Mw of rice kernels at different cooking temperatures and times was similar, but the molecular size and volume varied at different stages of cooking. The dismission of the crystalline structure, C1 resonance, and lamellar structures after cooking at 100 °C for 10 min indicated that the structural evolution of starch in rice kernels was time- and temperature-dependent. These results provide a promising foundation for developing strategies to control rice cooking., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The effects of frying temperature on the properties of wheat starch were investigated, including the microstructure, weight-average molar mass (M w ), crystalline properties, functional groups, in vitro digestibility, static rheological properties, swelling power and solubility. SEM micrographs showed that the disc-shaped starch granules ruptured after being fried, and formed a continuous and dense gel structure. With the increasing frying temperature, the starch molecules underwent violent degradation, and the M w decreased from 3.04 × 10 7  g/mol to 0.80 × 10 7  g/mol. The XRD and FTIR data indicated the formation of starch-lipid complexes during the frying process. In vitro digestion analysis revealed that the digestion rate of starch decreased, while the content of resistant starch (RS) increased after being fried. Besides, the shear stability of fried starch increased, whereas its swelling power and solubility decreased. These significant variations in physicochemical properties of starch could provide scientific basis for further improving the quality of instant noodles., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The production of French fries is a multistage process (blanching, pre-frying, freezing and final frying). Pre-stage processing can result in drastic changes related to the quality of the final product. In this study, we investigated the effect of multistage process on quality properties, water and oil distribution and microstructure of fries prepared with different oils. Results showed that freezing treatment had little effect on water and oil content, color and volumetric shrinkage of pre-fried fries. Final fried fries exhibited drastic changes involved in the content and status of water and oil, color, texture, volumetric shrinkage and microstructure compared with other processing stage. Besides, magnetic resonance imaging visualized a thicker crust in finish-fried fries. Among all the oils, fries fried in high-oleic sunflower oil showed the best mouthfeel. This will provide a theoretical guidance for food enterprise to produce high-quality French fries., (Copyright © 2020. Published by Elsevier Ltd.)

The composition and structure of starch are important indicators to evaluate the quality of rice, but the effect of protein on structural properties of rice has always been controversial. In the present study, the rheological properties and thermal properties were combined to investigate the effects of protein on mechanical and inner structure changes of rice kernel during cooking. The morphologic changes in overall form and inner structure of the kernel showed the limited and uneven gelatinization of starch, and reflected the good heating stability of protein. The comparison of molecular mobility in H 2 O/D 2 O reflected the special gelatinization behavior of starch and the hydrophobicity of protein during cooking. The similar proton distributions between starch, starch-protein mixture and rice flour indicated the weak interactions between starch and protein. The results of Fourier transform infrared spectra, thermogravimetric analysis and transmission electron microscope confirmed the wrapping effect of starch and surface interactions with protein., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Wheat is one of the most important grains in cereal products. Gluten protein is an important component of wheat and plays an important role in the human diet. The variations of gluten protein in you-tiao were investigated in this study during frying, with a view toward a theoretical basis for the improvement of processing methods and quality in you-tiao. During the processing of you-tiao, gluten protein altered significantly. Analysis of secondary structure and surface hydrophobicity indicated that gluten protein molecules were unfolded and decomposed after frying, providing the opportunity for protein reaggregation. The extractability and sodium dodecyl sulphate-polyacrylamide gel electrophoresis profiles demonstrated the decomposition and reaggregation of gluten protein. Analysis of the chemical interactions proved that gluten protein molecules aggregated mainly by disulfide bonds and hydrophobic interactions. Frying induced a loose and uneven gluten network., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Leaching and re-absorption of leached solids and changes in kernel structure are of prime importance for the quality of cooked rice. This paper describes the contents and structural changes of both starch and protein in leached solids and rice kernels. Under actual cooking conditions, the leached solids increased with heating temperature and then decreased at specific temperatures relating gelatinization. Starch content of leached solids increased with the heating temperature, especially after gelatinization. As proteins are mainly distributed on the surface of the kernel, their release increased between 30 and 50 °C but then decreased with increasing leaching of starch at high temperatures. The molecular weight distribution of leached solids at different temperatures is significantly different, while it is similar in rice kernels. At 30-50 °C, the amylose contents in the leached solids were slightly higher than those in rice kernel, while the contents were similar at high temperatures. The transformation of the kernel structure during heating confirmed that the kernel surface and the formed cracks are the main path for leaching; the rearranged structures of the surface and cracks influence the final texture of cooked rice., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The quality of cooked rice and its influence factors have always been the focus of researches. However, the formative mechanisms of its eating quality and structural changes of rice during cooking have seldom been evaluated. In this study, sectional real-time cooking was performed by differential scanning calorimetry (DSC) and dynamic viscoelasticity analysis to monitor the phase transitions and mechanical changes of kernels, which exhibited different characteristics in different stages. Both glass transition and pasting behavior were captured, and showed more viscoelasticity of cooked rice at higher soaking temperatures. Meanwhile, the enzyme activity of rice during soaking was successfully measured by a rapid viscosity analyzer (RVA). Along with the differences of morphologies and crystalline structure at different soaking conditions, the findings of DSC and rheometer were further verified. This study provides effective methods to evaluate changes in rice during cooking and explains the mechanism of differences formed by the soaking temperature., (Copyright © 2019. Published by Elsevier Ltd.)

This paper aimed to clarify the oil absorption behavior and microstructural changes of fresh and pre-frozen potato strips during frying, and to discuss the effects of freeze pretreatment on the oil absorption behavior of potato strips. We investigated the oil distribution; the microstructure changes in the crust, core, and potato strip surface; and the crystal pattern changes in the potato starch during frying by using magnetic resonance imaging, scanning electron microscopy, and X-ray diffraction. We monitored the profile histories of the moisture, oil and potato strip temperature, and oil uptake during frying and cooling. Results showed that during frying, the diversification of oil content in potato and oil infiltration path was closely related to the microstructure, moisture content, and temperature changes of potato strips and the interaction between starch and oil components. Moreover, freeze pretreatment significantly decreased the moisture content (P < .05) and increased oil content (P < .05) of potato strips and affected oil infiltration, microstructural changes, and starch crystallinity (P < .05) during frying. This paper may help in the further understanding of the oil absorption behavior of potato strips during frying and cooling, and may provide ideas for effective oil control measures., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The effects of different processing methods were investigated, including on the fluidity, solubility, nutrient composition, digestibility, color and aroma constituent of instant brown rice powder. It showed that, except for flavonoids, different processing methods significantly influenced the indexes of the instant brown rice flour (p < 0.05). Germination could deteriorate the fluidity and solubility of brown rice powder and reduce the digestibility of protein, and starch. Exogenous enzyme treatment improved the fluidity and solubility of the brown rice powder as well as the digestion rate of protein and starch. The synergistic treatment of germination and exogenous enzymes significantly increased the digestibility of starch, but it deteriorated the fluidity, the rate of agglomeration and dispersion time. Comparing with DGBRE, DBRE produced a better quality instant brown rice powder., (Copyright © 2018. Published by Elsevier Ltd.)

The effects of whole wheat flour (WWF) on pasting properties of instant fried noodle dry mix and quality of final product were investigated in this research. Refined wheat flour in the recipe for instant-fried noodle was replaced by WWF at different levels. The peak and final viscosities were significantly and negatively correlated to WWF substitution level. With increasing WWF level, the hardness, cohesiveness, adhesiveness, and resilience values of instant fried noodles decreased by 11.63, 16.23, 16.67, 20.00%, respectively. WWF darkened noodle's surface color and increased its oil content (26.63%). A porous and less uniformed structure of the WWF instant fried noodles was observed by a scanning electron microscope. Moreover, the WWF incorporation lowered peroxide values of the instant fried noodles during storage. In conclusion, even though the oil content increased, WWF was helpful to inhibit the oil oxidation and produce instant fried noodles with softer texture and less sticky surface., Practical Applications: Refined wheat flour in the recipe for instant-fried noodle was replaced by whole wheat flour (WWF), which is rich in dietary fibers, vitamins, and other bioactive compounds. The addition of WWF delayed the retrogradation tendency of starch in the dry mix. WWF-added instant noodles had softer texture, less sticky surface, and lower peroxide value. Based on the results of this study, the refined wheat flour in the recipe for instant-fried noodle could be partially replaced by WWF to make noodles with better texture profile and higher consumer acceptance., (© 2017 Wiley Periodicals, Inc.)

Oat samples of different varieties were collected from various habitats for the determination of avenacoside, β-glucan and fatty contents. The variation coefficients of the three components were 12.13%, 20.79% and 22.46%, respectively. Thus, those three indicators cannot represent the information of all samples, and are not suitable for evaluating the quality of oat raw materials and products. Fatty acid profiles were analyzed using gas chromatography combined with principal component analysis (PCA) and cluster analysis. Fourteen leather oat varieties were distinguished through a PCA scores scatterplot. Forty-six naked oat varieties were selected by cluster analysis and eleven characteristic peaks in these naked oats were identified. Finally, accurate fatty acid standard fingerprints of naked oats were constructed. The results of methodological indicated high precision, reproducibility and stability, in line with fingerprint testing requirements. This study fills the knowledge gap for naked oat fingerprint information, expands the grain fatty acid database, and lays the foundations of a grain nutritional liposome identification technology system. [ABSTRACT FROM AUTHOR]