α-Amylase is the second most widely produced enzyme globally, with diverse applications in the fields of food, pharmaceutical, bioenergy, papermaking, etc. However, natural α-amylase often fails to withstand the extreme conditions encountered in industrial processes, such as low pH and high temperatures. Previous studies identified an α-amylase derived from deep-sea sources with resistance to low pH, and subsequent amino acid mutations well enhanced its thermal stability. Nevertheless, the advantageous enzyme mutant exhibited low expression levels in Escherichia coli, highlighting the need for a more suitable expression host. In this study, an engineered industrial host, Komagataella phaffii, was involved for heterologous production of α-amylase. High-efficiency signal peptides were screened and multi-copy integrant strains were constructed to achieve a high-yield strain. A total of 31 key chaperones and 11 vesicle transport factors were further investigated to facilitate protein folding and secretion, which resulted in a 3.4-fold increase in α-amylase production. Finally, batch fermentation in a 3-L bioreactor achieved a maximum α-amylase activity of 2.5 × 10⁴U/mL. This study demonstrates the development of a high-yield α-amylase strain for potential industrial applications, offering valuable insights and strategies for engineering high-producing strains of other industrial enzymes.

Rice contains lysine, which is lacking in general grains, which can make the nutrition more balanced when it is added to cereal foods. Therefore, this study explored the effects of rice flour substitution on the structure and processing properties of mixed rice-wheat dough. With the addition of rice flour (0%–50%), the content of water, fat, protein, amylose, and ash in the mixed flour decreased, while that of total starch and amylopectin increased significantly. The results from the mechanical characteristics indicated that the viscosity disintegration (0.15–0.59 Nm) and β value (0.526–0.716) increased, while the retrogradation value (from 1.15 to 0.69 Nm) and the cooking stability (from 0.92 to 0.73) decreased, revealing that the shear resistance and stability of the mixed flour dough decreased after the addition of rice flour, but its increased gelatinization rate delayed aging and improved the storage characteristics. Moreover, mixed rice-wheat dough mainly underwent elastic deformation, and the addition of rice flour interfered with the formation of gluten network structure. Part of the bound water in the mixed flour dough migrates to free water, which showed that the continuity and uniformity of gluten network structure become worse by competing with wheat gluten for water absorption. When the addition of rice flour was 20%, the dough had the greatest viscoelasticity, micro-structure tensile property and texture, when the addition amount exceeded 30%, the toughness of the dough reduced, which made dough difficult to process. This study provides a theoretical basis for the processing and application of rice flour in staple food in the future.

In this study, the surface of cellulose nanocrystals was first modified with citric acid, and the resultant modified cellulose nanocrystals (MCNC) were subsequently utilized as a reinforcement phase for polylactic acid (PLA). Findings indicated that MCNC interacted with PLA through hydrogen bonding, resulting in improved thermal stability, mechanical properties, and surface hydrophobicity of PLA nanofiber films. Specifically, the thermal degradation temperature, tensile strength, elongation at break, and contact angle of the nanofiber films increased by 19°C, 30.04%, 49.11%, and 11.22°, respectively, with a 3% addition of MCNC. Subsequently, utilizing PLA/MCNC as the base material and kaempferol as the active ingredient, a preliminary exploration into its potential as an active packaging material was carried out. When the addition amount of kaempferol was 10%, the DPPH and ABTS free radical scavenging ability of the nanofiber film reached more than 90%, demonstrating its application potential as an active packaging material. These results offer a promising strategy for the effective dispersion of CNC within PLA matrices, thereby expanding the potential applications of PLA in the field of active packaging.

This study explored in vivo evolution as a method to generate evolutionary clones of Lacticaseibacillus rhamnosus GG, a renowned probiotic organism found in many food supplements, with improved persistence in the intestinal tract. L. rhamnosus GG was autologously gavaged to mice and subsequently selected and grown ex vivo after passage through the intestinal tract to form two evolutionary isolates of the bacteria. A longer retention time (nearly 3×) and a slower elimination rate of the bacteria in the mouse gut were observed with each evolution. The evolutionary isolates were further characterized for key traits such as bile salt resistance, epithelial cell binding, and genetic alterations to understand potential changes to known persistence mechanisms. Finally, a series of heterologous gavages were performed to determine if the increased retention of the evolutionary variants were because of animal-specific host adaptations. Similar results were seen following heterologous gavages, supporting the concept that intrinsic changes to Lacticaseibacillus occurred. Based on these findings, in vivo evolution shows promise as a technique to generate probiotic strains with improved traits for gut retention as compared to the wild type.

Xinhui Chenpi, a China National Geographical Indication Product, faces unexploited pulp resources, resulting in resource waste and potential environmental pollution. This study employed Xinhui citrus pulp as a raw material to produce Xinhui citrus wine (XCW), focusing on enhancing the aroma of XCW by utilizing a multi-strains fermentation involving Saccharomyces cerevisiae and Lachancea thermotolerans. The effect of S. cerevisiae Red and/or L. thermotolerans L19 on the enological parameters, physicochemical characteristics and volatile compounds of XCWs were evaluated. The mixed strains fermentation demonstrated a significant increase in esters content, including 2,3-butanediol dinitrate, diethyl succinate, ethyl benzoate, ethyl lactate, and ethyl glycolate compared to those of mono fermentation (p < 0.05), thereby enhancing the fruity and floral aromas of the XCW. The key aroma compounds of relative odor activity value (rOAV) > 1, which are specific to mixed fermentation, were ethyl 2-methylbutyrate, ethyl benzoate, ethyl isovalerate, ethyl propionate, 1-penten-3-ol, and phenylethyl alcohol. These compounds could strengthen the fruity, flowery, and sweet scents of XCW. The findings align with sensory evaluations, suggesting that the mixed fermentation of S. cerevisiae Red and L. thermotolerans L19 to produce XCW might resolve the resource waste of Xinhui citrus pulp.

Cd(II) and Hg(II) are well-known toxic heavy metal elements that are difficult to degrade by microorganisms in the environment. Limits for Cd(II) and Hg(II) in food have been established by the Chinese Government and other authorities. Aptamer-based electrochemical sensor detection is a promising method for rapidly and sensitively detecting heavy metals. However, aptamer configurations are easily affected by the environment and their stability needs to be improved. In this study, an ultra-sensitive electrochemical sensor was successfully constructed based on aptamer/dopamine molecularly imprinted polymer composite material, to explore the simultaneous detection of Cd(II) and Hg(II). Graphdiyne nanomaterial was used to increase the load of aptamer on the electrode surface. The aptamer of Cd(II) and Hg(II) was captured by AuNPs on a modified electrode through Au-S bonds. Dopamine was used as a functional monomer for self-polymerization to form an imprinted layer, stabilizing the aptamer conformation and enhancing its environmental tolerance. Under optimal conditions, the limits of detection (LOD) for Cd(II) and Hg(II) were 7.6 and 6.0 ng/mL, respectively. Six days of good stability in the sensor response were attained. The satisfactory recovery obtained in both crab and ribbonfish samples demonstrates this sensor's potential for multi-species food analysis.

Both tryptophan (Trp) and tyrosine (Tyr) play a significant role in the formation of volatile compounds in processes such as food processing and cigarette combustion. While the metabolic pathways of these amino acids have been extensively studied, their pyrolysis under cigarette-like conditions remains poorly understood. This study investigates the behavior of Trp and Tyr under conditions mimicking cigarette combustion using online pyrolysis-gas chromatography/mass spectrometry. Both amino acids were subjected to pyrolysis and analyzed using online pyrolysis-gas chromatography/mass spectrometry. Key findings reveal: (1) Pyrolysis of Trp and Tyr produced over 85 and 69 volatile compounds, respectively, with more than 98% of them containing aromatic rings. (2) The predominant pyrolysates were tyramine (46.92%) for Tyr and 3-methyl indole (46.19%) for Trp. (3) Key products included 3-methyl indole and indole from Trp, and p-methyl phenol (31.45%) and phenol (7.77%) from Tyr, resulting from cleavage of C2-C3 and C3-C4 bonds. (4) Pyrolysis products profiles proposed that the primary pyrolytic pathways included decarboxylation and cleavage of the C2-C3 and C3-C4 bonds. This research provides new insights into the pyrolytic behavior of Trp and Tyr, offering a better understanding of their role in smoke aroma and contributing to the broader field of pyrolysis chemistry in food science, smoke chemistry, and biomatrices utilization.

The sustainable utilization of agricultural waste holds immense promise in addressing environmental concerns and promoting resource efficiency. In this context, jackfruit (Artocarpus heterophyllus) peel waste emerges as a valuable yet underexplored resource. Therefore, this study aimed at the bio-functional and structural characterization of A. heterophyllus peel waste for unlocking its potential for food applications. By using cutting-edge and environmentally friendly technology, A. heterophyllus peel can be used as a bioresource (raw material) to obtain a variety of high-value biocompounds, in line with the circular bioeconomy philosophy. In this work, we examined A. heterophyllus peel, from its chemical composition to its functional and biological characteristics. Proximate analysis of the A. heterophyllus peel revealed the presence of protein (1%) and fiber (21%) content. Microscopic imaging (scanning electron microscopy and transmission electron microscopy) provided a comprehensive visual depiction of the peel's surface structure that possesses a high heat stability with peak disintegration observed at 200°C–300°C that was detected by thermogravimetric analysis. The findings of phytochemical screenings reported the presence of various bioactive compounds, such as alkaloids, steroids, glycosides, and tannins. Notably, the peel exhibited inhibitory effects against several bacterial strains, including Alcaligenes faecalis, Staphylococcus aureus, and Escherichia coli in the antimicrobial analysis. Additionally, Fourier-transform infrared spectroscopy analysis identified the presence of alcohols and phenols, while X-ray diffraction data displayed characteristic diffraction peaks at 20°–25°. In conclusion, this study identified the potential utility of A. heterophyllus peel as a valuable source of phytochemical compounds, polyphenolic antioxidants, and the antimicrobial additives that can be used in wide agri-food-pharma industries.

Essential oils are widely recognized for their antimicrobial properties, making them promising natural alternatives for food preservation and spoilage prevention. However, practical challenges such as hydrophobicity, instability, and strong aroma have limited their applications. To overcome these challenges, this study aimed to prepare nanoemulsions of eugenol and neem oil using ultrasonication techniques and evaluating their antimicrobial efficacy, highlighting their potential for sustainable food preservation. The antimicrobial efficacy of these nanoemulsions was evaluated against four foodborne bacteria and spoilage fungi using well diffusion method. Nanoemulsions, formulated with oil concentrations of 5%–20%, exhibited particle sizes ranging from 135 to 373 d.nm for neem oil and 410 to 587 d.nm for eugenol, with polydispersity indices indicating variable size distribution (0.27–0.88 for neem oil and 0.13–0.60 for eugenol). Stability tests confirmed overall stability, although some eugenol-based nanoemulsions exhibited minor precipitation due to turbidity. Both neem oil and eugenol nanoemulsions displayed significant antimicrobial activity, with eugenol being more effective even at lower concentrations. NNE-20 showed the largest inhibition zones against Bacillus subtilis (17.83 mm), Escherichia coli (14.83 mm), and Enterobacter aerogenes (14.16 mm), while NNE-15 was most effective against Staphylococcus aureus (14 mm). Eugenol nanoemulsions exhibited superior antibacterial activity, achieving inhibition zones of 18–23.5 mm with higher eugenol concentrations. For fungi, neem oil nanoemulsions inhibited Colletotrichum gloeosporioides, Rhizopus stolonifer and Aspergillus niger (15–20 mm), while eugenol nanoemulsions outperformed neem oil, showing zones of 24–26 mm (Aspergillus niger) and 20–24 mm (Saccharomyces cerevisiae). These findings highlight the potential of neem oil and eugenol nanoemulsions as stable, natural, and effective alternatives to synthetic preservatives for improving food safety and extending shelf life.

The goal of this study was to establish an efficient protocol for producing bioactive-rich mushroom extracts for food ingredients development. For this, fresh mushrooms were dried, ground, and submitted to different extraction protocols—ethanolic (EE), fermentation-assisted (FAE), or enzyme-assisted extraction (EAE). In addition, ultraviolet B (UV-B) irradiation, coupled with the extraction protocols, was experimentally studied for potential improvement of extracts bioactivity and yields. The extraction yield (EY), bioactivity (total phenolic content TPC, phenolic acids, flavonoids, and antioxidant activity), α-, β-, and total glucan contents, and mineral content were evaluated. EAE yielded the highest EY (26.48%–31.30%) while EE resulted in the highest TPC, phenolic acids, flavonoids, and antioxidant activity (p < 0.05). The β-glucan content (0.13%–0.93%) was not affected by extraction type or UV-B irradiation (p > 0.05). All extracts were rich in essential minerals with low potential toxicity. Based on the high EY, phenolic load, antioxidant activity, glucans, and mineral contents, EAE proved to be an effective method to obtain bioactive-rich mushroom extracts. Overall, UV-B irradiation did not show significant results in improving bioactivity of mushroom extracts. Our results deliver a realistic roadmap to explore mushrooms as rich sources of phytochemicals for food and nutraceuticals applications.