Mechanochemical effects on the structural properties of wheat starch during vibration ball milling of wheat endosperm

Micronization induced gelatinization of tapioca starch and its effects on starch physicochemical and structural properties

The vibrating superfine mill (VSM) is a machine that belongs to the micronization technique. In this study, VSM was employed to produce micronized tapioca starch by varying micronization times (15, 30, 45, and 60 min). The structural and physicochemical properties of the micronized starch were then examined. Scanning electron microscopy studies revealed that micronized starch was partially gelatinized, and the granule size dramatically increased when micronization time increased. X-ray diffraction patterns showed that the relative crystallinity was decreased from 24.67% (native) to 4.13% after micronization treatment for 15 min and slightly decreased after that. The solubility of micronized starch significantly increased as the micronization time increased, which was associated with the destruction of the starch crystalline structure. Differential scanning calorimetry investigations confirmed that micronized starch was "partly gelatinized," and the degree of gelatinization increased to 81.27% when the micronization time was 60 min. The weight-average molar mass was reduced by 15.0% (15 min), 30.9% (30 min), 55.7% (45 min), and 70.5% (60 min), respectively, indicating that the molecular structure was seriously degraded. The results demonstrated that the physicochemical changes of micronized starch granules were related to the destruction of the starch structure. These observations would provide details on micronized starch and its potential applications. PRACTICAL APPLICATION: These observations would provide details on micronized starch and its potential applications. Moreover, we believe that when the structures of starches were known, it is probable that the effect of VSM on the structural and physicochemical properties change of other starches might be predicted by adjusting the processing time.

In vitro digestibility of starch and protein in cooked wheat and oat whole flours: A comparative study

Whole grains have garnered significant attention in the food industry due to their retained abundant nutrients when compared to refined grains. However, limited knowledge exists regarding the digestive behavior of starch and protein. This study compared the physicochemical properties and in vitro starch and protein digestibility of cooked whole wheat flour (WF) and naked oat flour (NOF), and evaluated the impact of endogenous components (protein, lipid, β-glucan, and polyphenol) on the physicochemical properties and digestibility of WF and NOF. The result indicated that the final hydrolysis rate of WF samples (starch: 23.2 %∼46.3 %; protein: 23.1 %∼63.0 %) was lower than that of NOF samples (starch: 32.1 %∼61.0 %; protein: 32.3 %∼63.6 %). The removal of different endogenous components led to improved digestibility of starch and protein in both WF and NOF. This study contributes to the understanding of the starch and protein digestibility of whole grains, consequently facilitating the development of whole grain products.

Flavor Characteristics, Antioxidant Activity and In Vitro Digestion Properties of Bread with Large-Leaf Yellow Tea Powder

Foods containing tea could be widely utilized due to the addition of good tea ingredients, especially large-leaf yellow tea, which is rich with a good flavor. Applying this change to bread containing tea would improve its product quality. In this research, large-leaf yellow tea bread (LYB), possessing a special flavor, was developed using ultrafine large-leaf yellow tea powder and flour as the main raw materials. The amount of ultrafine large-leaf yellow tea powder added to bread was optimized using texture, sensation, and specific volume as comprehensive evaluation indicators. At the optimal dosage, the free amino acids, volatile flavor compounds, antioxidant activity, and in vitro starch digestibility of LYB were measured. Response surface optimization experimental results showed that the comprehensive score of bread was highest when the added amount of ultrafine large-leaf yellow tea powder was 3%. In particular, compared to blank bread (BB), adding ultrafine large-leaf yellow tea powder into bread could effectively increase its amino acid composition, enhance its volatile flavor compounds, improve the antioxidant capacity, and reduce the digestibility of starch.

Inhibition mechanism of rice glutelin on extruded starch digestion: From the structural properties of starch and enzyme activity

To increase the anti-digestion ability of extruded rice starch (ERS), the influence of rice glutelin (RG) on digestive and structural characteristics of ERS were investigated. The resistant starch content increased from 4.49 % to 18.08 % as the RG content increased, while the digestion rate and digestion velocity constant were reduced by the incorporation of RG. Morphological observations showed that ERS was adhered and encapsulated by RG, and the specific area of starch granules were decreased after the addition of RG. The results of XRD and FTIR suggested that the long-range and short-range orders of ERS were improved due to the complexation with RG. The thickness of crystalline of ERS was increased while its amorphous region thickness was reduced by the supplementation with RG. The 1H NMR and 13C NMR data revealed that the branching degree and double helix content of ERS was increased by 46.24 % and 52.67 % when RG content reached to 12 %. Additionally, the addition of RG altered the molecular weight and chain length distribution of ERS. The α-amylase activity and glucoamylase activity was inhibited by RG. These results could provide a valuable basis for the application of RG in extruded rice starchy foods with lower glycemic index.

Mechanochemical Degradation of Biopolymers

Mechanochemical treatment of various organic molecules is an emerging technology of green processes in biofuel, fine chemicals, or food production. Many biopolymers are involved in isolating, derivating, or modifying molecules of natural origin. Mechanochemistry provides a powerful tool to achieve these goals, but the unintentional modification of biopolymers by mechanochemical manipulation is not always obvious or even detectable. Although modeling molecular changes caused by mechanical stresses in cavitation and grinding processes is feasible in small model compounds, simulation of extrusion processes primarily relies on phenomenological approaches that allow only tool- and material-specific conclusions. The development of analytical and computational techniques allows for the inline and real-time control of parameters in various mechanochemical processes. Using artificial intelligence to analyze process parameters and product characteristics can significantly improve production optimization. We aim to review the processes and consequences of possible chemical, physicochemical, and structural changes.

Ball-milling: A sustainable and green approach for starch modification

Ball-milling is a low-cost and green technology that offers mechanical actions (shear, friction, collision, and impact) to modify and reduce starch to nanoscale size. It is one of the physical modification techniques used to reduce the relative crystallinity and improve the digestibility of starch to their better utility. Ball-milling alters surface morphology, improving the overall surface area and texture of starch granules. This approach also can improve functional properties, including swelling, solubility, and water solubility, with increased energy supplied. Further, the increased surface area of starch particles and subsequent increase in active sites enhance chemical reactions and alteration in structural transformations and physical and chemical properties. This review is about current information on the impact of ball-milling on the compositions, fine structures, morphological, thermal, and rheological characteristics of starch granules. Furthermore, ball-milling is an efficient approach for the development of high-quality starches for applications in the food and non-food industries. There is also an attempt to compare ball-milled starches from various botanical sources.

Structure characteristics and physicochemical property of starch, dietary fiber, protein in purple corn flour modified by low temperature impact mill

The structural changes of macromolecules (starch, dietary fiber and protein) in purple corn flour (PCF) modified by a low temperature impact mill (LTIM) at different air classifier speed (ACS) were investigated. LTIM changed the multi-scale structure of starch, which was characterized by increased starch damage, stronger destruction of relative crystallinity (from 37.85 % to 15.53 %) and short-range ordered structure (R_1047/1022, from 1.21 to 0.73) with the increased ACS. The structure of dietary fiber was also destroyed on multi-level, including decreased particle size, destructive morphology, and slightly changed crystalline structure. Additionally, LTIM showed high damage on the senior structure (surface hydrophobicity, disulfide bond, secondary structure) of protein. Due to the structure changes modified by LTIM, starch, dietary fiber and protein played different role on hydration property of PCF. Starch had positive effect, while dietary fiber and protein had negative effect. Our experimental results may provide valuable information for further analysis of other quality changes (oil holding capacity, cation exchange capacity, ability to produce high-quality dough or end-out products, etc.) of purple corn flour after LTIM treatment.

Integrated Technology for Cereal Bran Valorization: Perspectives for a Sustainable Industrial Approach

Current research focuses on improving the bioaccessibility of functional components bound to cereal bran cell walls. The main bioactive components in cereal bran that have major biological activities include phenolic acids, biopeptides, dietary fiber, and novel carbohydrates. Because of the bound form in which these bioactive compounds exist in the bran matrix, their bioaccessibility is limited. This paper aims to comprehensively analyze the functionality of an integrated technology comprising pretreatment techniques applied to bran substrate followed by fermentation bioprocesses to improve the bioaccessibility and bioavailability of the functional components. The integrated technology of specific physical, chemical, and biological pretreatments coupled with fermentation strategies applied to cereal bran previously-pretreated substrate provide a theoretical basis for the high-value utilization of cereal bran and the development of related functional foods and drugs.