Gang Wu

The article discusses the main scientific directions and results of research in the field of mechanical engineering conducted at Shakarim University in Semey. The publications in the series "Engineering Sciences" of the Shakarim University Bulletin are analyzed, reflecting the evolution of topics - from material hardening technologies to the design of specialized equipment and the implementation of intelligent systems. It is shown that university scientists have achieved significant success in increasing the wear resistance and durability of materials, developing small-sized special equipment for agriculture and construction, as well as in integrating modern digital approaches (IoT, automation) into traditional engineering tasks. Special attention is paid to the forms of scientific collaboration: internal interaction of departments and research centers of the university, participation of students, as well as partnership with industry and foreign universities. The most innovative works that demonstrated significant improvement in the properties of materials and the effectiveness of the developed engineering solutions are emphasized.

This study aimed to develop and optimize edible antimicrobial films using electron beam-irradiated starches and biopolymer additives. Rice starch (“Marzhan” variety) and cassava starch (“Cassava 531” variety) were physically modified via irradiation at doses of 0, 3, 6, and 9 kGy using an ILU-10 accelerator. Film-forming solutions were prepared by blending starch, chitosan, and glycerol, followed by casting and drying. One-Factor-at-a-Time (OFAT) screening was conducted to evaluate the effects of starch content, gelatinization time, glycerol, and chitosan on film properties including tensile strength (TS), elongation at break (EAB), water vapor permeability (WVP), and transparency.A Box–Behnken Design (BBD) based on Response Surface Methodology (RSM) was used for multi-factor optimization. The regression model for transparency (%) revealed that starch and chitosan contents had positive linear effects but exhibited diminishing returns due to significant negative quadratic terms. Gelatinization time and glycerol content showed negative linear effects on transparency, while several interaction terms also influenced the response.Although the model demonstrated modest statistical significance (R² = 35.05%), it highlighted complex factor interdependencies and provided direction for optimal formulation. The findings support the potential of irradiated starch in functional biodegradable films and offer a foundation for future development of sustainable packaging materials with improved physical and barrier properties.

The inhibition mechanism of buckwheat phenolics on in vitro starch digestion was investigated using extruded noodles with buckwheat starch and phenolic extract (0.50%–2.00%). The cooking quality and reducing sugar released during in vitro digestion were studied, and the extractable phenolic content along digestion was also monitored to reveal a dose–effect relationship between reducing sugar released and the release of phenolics. Noodles containing increased phenolics released less reducing sugar (230–188 mg g⁻¹) during digestion. Cooking and digestion made phenolics more extractable, and most of the phenolics were released at the end of the gastric phase (85.6%–94.8%) compared with during the small intestinal digestion. The IC₅₀ of buckwheat phenolic extract (0.102 mg mL⁻¹) was four times that of acarbose (0.032 mg mL⁻¹). The inhibitory mechanism was further analysed using molecular docking, in which the activity of α‐amylase was inhibited by phenolics that bind with active sites of α‐amylase through hydrogen bonds and hydrophobic interaction. Phenolics interacting with starch and the released phenolics can both explain the reduction in starch digestion.

Sorghum biscuits were enriched with mushroom powders (Lentinula edodes, Auricularia auricula and Tremella fuciformis) at 5%, 10% and 15% substitution levels. An in vitro gastrointestinal digestion was used to evaluate the effect of this enrichment on the phenolic content and soluble peptide content as well as antioxidant activities of the gastric or intestinal supernatants (bio-accessible fractions), and the remaining portions of phenolic compounds, antioxidants and β-glucan in the undigested residue (non-digestible fraction). The phenolic content of the gastric and intestinal supernatants obtained from digested mushroom-enriched biscuits was found to be higher than that of control biscuit, and the phenolic content was positively correlated to the antioxidant activities in each fraction (p < 0.001). L. edodes and T. fuciformis enrichment increased the soluble protein content (small peptide) of sorghum biscuits after in vitro digestion. All mushroom enrichment increased the total phenolic content and β-glucan content of the undigested residue and they were positively correlated (p < 0.001). The insoluble dietary fibre of biscuits was positively correlated with β-glucan content (p < 0.001) of undigested residue. These findings suggested that enriching food with mushroom derived dietary fibre increases the bioavailability of the non-digestible β-glucan and phenolic compounds.

Summary: Phenolic compounds have been shown to deliver numerous health benefits. Research has also shown that starch and phenolic compounds interact. This study aimed to investigate the effects of blackcurrant and strawberry powder on the physicochemical and in vitro predicted glycaemic response of sweet potato and potato starches. Sweet potato, or potato, starches were mixed with 0%, 5%, 10% and 15% (w/w) of blackcurrant, or strawberry, powder, to form blackcurrant and strawberry‐enriched starch pastes. The results showed that enrichment with 5%, 10% and 15% blackcurrant or strawberry powder for sweet potato and potato starch significantly altered the pasting viscosity and colour profiles (P < 0.05), increased the phenolic content and antioxidant activities of starch pastes (P < 0.05). Blackcurrant or strawberry powders mixed with sweet potato or potato starches reduced amount of reducing sugar released during in vitro digestion. Addition of 15% blackcurrant powder for the starch exerted stronger in vitro antioxidant and hypoglycaemic properties than that of 15% strawberry powder. Collectively, these findings suggested that addition of blackcurrant or strawberry powder into sweet potato and potato starches manipulated the hypoglycaemic property of pastes.