Gas chromatography–ion mobility spectroscopy (GC-IMS) was used to analyze the volatile components in dried Hypsizygus marmoreus of different drying methods, including hot air drying (HAD), heat pump drying (HPD), heated freeze-drying (HFD), and unheated freeze-drying (UFD). A total of 116 signal peaks corresponding to 96 volatile compounds were identified, including 25 esters, 24 aldehydes, 23 alcohols, 13 ketones, 10 heterocyclic compounds, 8 carboxylic acids, 7 terpenes, 3 sulfur-containing compounds, 2 nitrogen-containing compounds, and 1 aromatic hydrocarbon. The total content of volatile compounds in H. marmoreus dried by the four methods, from highest to lowest, was as follows: HAD, HPD, HFD, and UFD. The main volatile compounds included carboxylic acids, alcohols, esters, and aldehydes. Comparing the peak intensities of volatile compounds in dried H. marmoreus using different drying methods, it was found that the synthesis of esters, aldehydes, and terpenes increased under hot drying methods such as HAD and HPD, while the synthesis of compounds containing sulfur and nitrogen increased under freeze-drying methods such as HFD and UFD. Nine common key characteristic flavor compounds of dried H. marmoreus were screened using relative odor activity values (ROAV > 1), including ethyl 3-methylbutanoate, acetic acid, 2-methylbutanal, propanal, methyl 2-propenyl sulfate, trimethylamine, 3-octanone, acetaldehide, and thiophene. In the odor description of volatile compounds with ROAV > 0.1, it was found that important flavor components such as trimethylamine, 3-octanone, (E)-2-octenal, and dimethyl disulfide are related to the aroma of seafood. Their ROAV order is HFD > UFD > HPD > HAD, indicating that H. marmoreus using the HFD method have the strongest seafood flavor. The research findings provide theoretical guidance for selecting drying methods and refining the processing of H. marmoreus.

Hypsizygus marmoreus has abundant proteins and is a potential source for the development of bioactive peptides. However, currently, the research on the bioactive components of H. marmoreus mainly focuses on polysaccharides, and there is no relevant research on the preparation of bioactive peptides. In this article, an ultrasound-assisted extraction method was used to extract proteins from H. marmoreus, and then, four peptides with different molecular weight ranges were prepared through protease hydrolysis and molecular classification. The antioxidant and antibacterial activities were also studied. Under the optimal conditions, the extraction rate of H. marmoreus proteins was 53.6%. Trypsin exhibited the highest hydrolysis rate of H. marmoreus proteins. The optimal parameters for enzymatic hydrolysis were a substrate concentration of 3.7%, enzyme addition of 5700 U/g, pH value of 7, extraction temperature of 55 °C, and time of 3.3 h. Under these conditions, the peptide yield was 59.7%. The four types of H. marmoreus peptides were prepared by molecular weight grading. Among them, peptides with low molecular weight (<1 kDa) had stronger antioxidant and antibacterial activities. This study provides a theoretical basis for the efficient preparation of H. marmoreus peptides and the development of antioxidant and antibacterial peptide products.

Instant Tremella fuciformis is ready to eat after adding hot water and is a delicious edible mushroom food. However, the drying method affects the quality of product. The present work evaluated the effects of freeze drying (FD), microwave drying (MD), and hot air drying (HAD) on shrinkage ratio, rehydration ratio, microstructure, polysaccharide and free amino acids of instant Tremella fuciformis. These three drying methods significantly changed the color and reduced the total amount of amino acids of dried products. FD sample possessed a three-dimensional network with porous, loose and large voids, so it had a slighter shrinkage and a better rehydration effect compared with the MD and HAD one. The polysaccharide content, uronic acid content and soup’s viscosity of FD products were significantly higher than MD and HAD. Therefore, FD was more suitable for obtaining high-quality instant Tremella fuciformis products than MD and HAD.

Resveratrol is an important phytoalexin that adapts to and responds to stressful conditions, plays various roles in health and medical therapies. However, it is only found in a limited number of plant species in low concentrations, which hinders its development and utilization. Chalcone synthase (CHS) and stilbene synthase (STS) catalyze the same substrates to produce flavonoids and resveratrol, respectively. However, it remains unclear how CHS and STS compete in metabolite synthesis. In this study, two CHS2 mutant cell lines (MT1 and MT2) were generated using CRISPR/Cas9 genome editing. These CHS2 mutant cell lines exhibited abundant mutations in CHS2, leading to the premature termination of protein translation and subsequent CHS2 knockout. Amplicon sequencing confirmed comprehensive CHS2 knockout in MT1, whereas the wild-type sequence remained predominant in the MT2 cell line. Transcriptome and RT-qPCR results showed a significant downregulation of genes involved in flavonoid biosynthesis, including CHS2, CHS3, F3H, F3’H, DFR, FLS, LDOX, among others, resulting in decreased flavonoid accumulation, such as anthocyanins, proanthocyanidins, quercetin, and kaempferol. Conversely, STS genes involved in stilbenoid biosynthesis were upregulated competing with the flavonoid pathway. Consequently, there was a marked increase in stilbenoids, including resveratrol, piceatannol, piceid and pterostilbene, with a 4.1-fold increase in resveratrol and a 5.3-fold increase in piceid (a derivative of resveratrol) observed in CHS2 mutant cell lines. This research demonstrates that CHS2 mutation induces a shift from flavonoid biosynthesis towards stilbenoid biosynthesis, offering new insights into metabolite biosynthesis and regulation, as well as an alternative solution for natural resveratrol production, and a novel breeding approach for eliminating non-target agronomic traits using CRISPR-Cas9.

This study conducted a systematic comparison of four drying methods (vacuum freeze-drying, spray drying, spray freeze-drying, and hot air drying) on abalone bioactive peptides, investigating their effects on physicochemical properties and nutritional composition. Scanning electron microscopy revealed distinct morphological characteristics: hot-air-dried samples showed compact structures with large particles, and vacuum-freeze-dried samples exhibited flaky morphology, while spray-freeze-dried and spray-dried samples demonstrated advantageous smaller particle sizes. Spray freeze-drying achieved superior emulsification capacity and fat absorption, significantly higher than hot air drying. The enhanced performance was attributed to increased exposure of hydrophobic amino acid residues and improved surface activity. Regarding nutritional composition, vacuum freeze-drying demonstrated optimal protein and total amino acid preservation, while spray freeze-drying showed the highest retention of Ca and Fe. Interestingly, hot air drying exhibited superior vitamin A retention, attributed to its fat-soluble nature and stability below 100 °C. The particle size reduction in spray-freeze-dried samples enhanced solvent–solute contact area, contributing to improved solubility and consequently superior foaming properties. These findings provide valuable insights into the relationship between drying methods and product characteristics, offering guidance for optimizing processing conditions in marine protein production.

Weizmannia coagulans is increasingly employed in food processing owing to its health benefits. Our previous research developed Oolong tea-fortified rice noodles with unique flavor and potent antioxidant activity; however, their texture still requires improvement. In this study, Oolong tea-fortified rice noodles were fermented using W. coagulans PR06 at inoculation amounts of 1%, 3%, and 5% (v/v), and assessed for cooking quality, texture, and starch digestibility. The results indicated that fermentation with 3% and 5% W. coagulans PR06 altered the amylopectin length distribution in the rice noodles and increased the degree of starch short-range order. Furthermore, the fermentation process increased the storage modulus (G′) and loss modulus (G″) values, decreased the tan δ value, and strengthened the interactions among tea polyphenols, proteins, and starch in the rice flour gel. Consequently, this process increased the hardness and chewiness of the rice noodles, decreased their broken strip rate and cooking loss, and significantly reduced their in vitro starch digestibility. Overall, fermentation with W. coagulans PR06 markedly improved the texture and cooking quality of Oolong tea-fortified rice noodles while effectively delaying starch digestion. This study highlights the potential application of W. coagulans PR06 in developing diverse and functional rice noodle products.