To compare the effects of drying methods on the taste of Sichuan Congou black tea. In this study, quantitative descriptive analysis, high-performance liquid chromatography, and ultra-high-performance liquid chromatography-mass spectrometry combined with multivariate statistical analysis were employed to investigate taste differences among teas produced using different drying methods: Jinqu (hot-air drying), Jinzhen (carding machine drying), and Xiangluo (double-pan roasting drying). Results indicated that Jinqu exhibited a sweeter, fresher taste and achieved the highest sensory score (91.96). In contrast, Xiangluo had a darker liquor, higher bitterness and sourness, and the lowest sensory score (88.97). Jinzhen displayed intermediate sensory characteristics. The free amino acid content of Jinqu (4.34%) was significantly higher than that of Jinzhen and Xiangluo (P<0.05), with its theanine content being 1.41 and 1.48 times higher, respectively. Additionally, the phenol-to-amino ratio in Jinqu (1.76) was lower than that in Jinzhen (2.32) and Xiangluo (2.39). The theabrownin content of Xiangluo (3.24%) was significantly higher than that of Jinzhen and Jinqu (P<0.05), whereas Jinqu had the highest theaflavin (0.26%). The total catechin content in Xiangluo exceeded that of Jinqu and Jinzhen by 30.34% and 4.83%, respectively. Metabolomics and Pearson correlation analyses showed that elevated relative contents of amino acids (L-asparagine, L-theanine, and L-glutamic acid) in Jinqu notably enhanced its freshness. In contrast, Xiangluo contained higher levels of ester catechins and flavonoids but lower amino acids, thus increasing bitterness and reducing freshness. Moreover, malic and fumaric acids contributed to increased acidity in Xiangluo tea liquor. In conclusion, Jinqu tea produced by hot-air drying exhibited superior flavor quality compared with teas produced by the other two drying methods. These findings provide a theoretical basis for optimizing processing techniques and enhancing Sichuan Congou black tea quality.

The dynamic variation patterns of volatile components during the processing of sea buckthorn leaf green tea were investigated using gas chromatography-electronic nose (GC-E-Nose) and headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS), combined with partial least squares discrimination analysis (PLS-DA) and orthogonal PLS-DA (OPLS-DA). Qualitative and relative quantitative analyses of volatile substances were performed across six processing stages of sea buckthorn leaves. These were fresh leaves (XY), steam fixation (ZQ), rolling (RN), pan-firing (CQ), aroma enhancement (ZX), and finished tea (CP). The results showed that there were significant differences in the tea aroma profiles among the different processing stages. A total of 70 volatile components were identified in six samples. These covered eight major categories, including alcohols and aldehydes, of which aldehydes, alcohols, and olefins were the dominant core categories. During processing, the volatile components showed strong stage-specific evolution. The relative contents of the aldehydes continuously increased from 28.24% in fresh leaves to 58.64% in the finished tea and became the most abundant category. In contrast, alcohols and esters decreased sharply throughout the entire process and olefins increased to five times that of fresh leaves at the rolling stage. The aroma profile showed a characteristic trend of "green leaf aroma fading, floral and fruity aromas enriching", with the finished tea having a composite aroma dominated by floral (37.09%) and fruity (23.48%) notes. The OPLS-DA model based on HS-SPME-GC-MS (R²X=0.945, R²Y=0.982, Q²=0.960) identified 22 key volatile compounds, of which nonanal content was the highest. The different processing procedures led to the formation of specific dominant components: Steam fixation facilitated the accumulation of (Z)-2-hexen-1-ol, whereas rolling promoted the release of terpinolene. This study revealed that enzymatic reactions occurred prior to steam fixation. These enriched the aroma components in subsequent processing, which then regulated aroma formation via mechanisms such as thermal degradation and cell disruption. These results reveal the complex dynamic changes in volatile compounds and provide a theoretical basis for sea buckthorn leaf green tea process optimization and quality improvement.

The study investigated the effects of modifying pineapple insoluble dietary fiber (PIDF) using ultrasonic (US), ultra-high-pressure homogenization (UHPH), hydrochloric acid (HCl), or alkaline hydrogen peroxide (AHP) treatment on its structural and functional properties. The correlation between PIDF structural characteristics and functional properties were analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), particle size analysis, hydration property analysis, and measurements of glucose and nitrite adsorption capacities. The results showed that all four modification methods significantly altered PIDF structural characteristics and functional properties. SEM revealed increased surface folds and porosity in the modified samples, and particle size analysis demonstrated significant reductions in particle size (P<0.05). Fourier-transform infrared (FT-IR) spectroscopy revealed that no new functional groups were introduced. Among the four modification methods evaluated, alkaline hydrogen peroxide (AHP) treatment exhibited the greatest improvement in hydration properties, increasing water holding capacity to 23.91 g/g and oil holding capacity to 19.68 g/g, while ultrasonic (US) treatment yielded the highest water swelling capacity (12.78 mL/g). Regarding adsorption properties, US treatment showed the strongest glucose adsorption capacity (862.74 mg/g). AHP treatment achieved the best nitrite ion adsorption capacity at pH2.0 (450.66 μg/g), and ultra-high pressure homogenization (UHPH) treatment was most effective for cholesterol adsorption (4.11 mg/g). These results suggested that AHP was more suitable for enhancing hydration-related properties, whereas UHPH was preferable for improving adsorption performance. In summary, the four modification methods not only altered the physical structure of pineapple insoluble dietary fiber (PIDF), but also improved its chemical functional characteristics, thereby expanding its potential applications.

This study aimed to investigate the effects of microwave pretreatment on the quality characteristics of coarse cereals, and develop a kind of mixed coarse cereal rice with simultaneous cooking maturity. Four types of coarse cereals—mung bean, black bean, red bean, and black rice—were selected as raw materials. The optimal soaking time was determined based on water absorption rates. The influence of microwave duration on the gelatinization degree and sensory scores of the four coarse cereals was studied. Comparative analysis was conducted on the quality changes of the coarse cereals before and after pre-ripening. The proportion of the mixed coarse cereal rice was determined using sensory score as an indicator, and its digestive properties were examined. The results showed that the optimal soaking times for mung beans, black bean, red bean, and black rice were 3, 3, 8, and 2 h, respectively, while the optimal microwave times were 5, 5, 6, and 4 min, respectively. After pre-ripening, the moisture and fat content of the four coarse cereals significantly decreased, starch content significantly increased (P<0.05), and protein content remained largely unchanged (P>0.05). Pre-ripening reduced the cooking time of the coarse cereals while increasing their rehydration rate, volumetric expansion rate, and cooking loss rate. The color of the four coarse cereals was affected to varying degrees by pre-ripening. Additionally, pre-ripening significantly reduced the hardness and chewiness of the coarse cereals while significantly increasing their elasticity (P<0.05), making their texture more similar to that of cooked rice. Except for mung beans, the odor response values of black beans, red beans, and black rice increased after pre-ripening. With the exception of black beans, the viscosity, breakdown, and setback values of mung bean, red bean, and black rice significantly decreased after pre-ripening, while their gelatinization temperature significantly increased (P<0.05). The optimal formulation for the mixed coarse cereal rice was determined as follows: Pre-ripened mung bean:pre-ripened black bean:pre-ripened red bean:pre-ripened black rice:regular rice=15:10:5:21:49. Compared with rice, this mixed coarse cereal rice had a higher content of slow digestible starch and resistant starch, which were 45.16% and 26.45% respectively, and its estimated glycemic index (GI) was 64.61, which was a medium GI food. These findings provide data support for the application of microwave precooking in coarse cereal processing and contribute to the advancement of the coarse cereal processing industry.

To enhance the stability and bioavailability of astaxanthin (AST), soy protein isolates (SPI) were used as the raw material to prepare SPI/chitosan (CS) composite nanoparticles for the encapsulation of AST. The study investigated the effect of CS on the encapsulation efficiency of AST. Ca²⁺ were then introduced as stabilizer to investigate their effect on the stability of the SPI/CS/AST nanodispersion and to elucidate the underlying mechanism. The results demonstrated that at a CS concentration of 0.6 mg/mL, the encapsulation efficiency of AST reached 59.57%, representing an 11% increase compared to samples without CS. Under this CS concentration, when Ca²⁺ was added at 0.2 mg/mL, the AST encapsulation efficiency further rose to 73.55%, a 20% improvement over samples without Ca²⁺. Moreover, at a storage temperature of 4 ℃, the retention rate of AST increased by 14% with Ca²⁺ addition. Under ultraviolet irradiation, 0.2 mg/mL Ca²⁺ provided the most effective protection for AST within the nanodispersion, enhancing retention by 23% compared to those without Ca²⁺. Furthermore, the retention rates of encapsulated AST in simulated gastric and intestinal fluids reached 78.35% and 67.18%, respectively. Ultraviolet and fluorescence spectroscopy analysis revealed that Ca²⁺ enhanced stability by influencing hydrogen bonds and hydrophobic interactions in the nanodispersion through ionic bridging, electrostatic neutralization, and conformational regulation. In summary, this study successfully established a highly stable AST nano-delivery system through the synergistic effect of SPI/CS composite wall materials and Ca²⁺, providing a theoretical basis for the application of AST in the development of functional foods.

This study established bovine serum albumin (BSA)-fructose and a BSA-methylglyoxal (MGO) model system to explore the inhibitory mechanisms of two flavonoids, naringenin and naringin, against advanced glycation end products (AGEs). The inhibitory effects of naringenin and naringin on the glycation products at different stages of the reaction and their protective effects on the protein structures were measured. Notably, the structures of the adducts formed by them and MGO were elucidated to further investigate their anti-glycation abilities. The results showed that the inhibitory rates of naringenin and naringin against AGEs increased with increasing concentration. When the naringenin and naringin concentration was 2 mg/mL, their inhibitory rates against AGEs in both the BSA-fructose and BSA-MGO systems were >80%, which was significantly higher (P<0.05) than that of aminoguanidine. In terms of protein structure protection, they protected the microenvironment of protein fluorophores, with a fluorescence recovery rate of >25%. In addition, they increased the content of free sulfhydryl groups as well as the inhibitory rate against kynurenine, both of which reaching >95%. These increases effectively inhibited the formation of protein oxidation products. High-performance liquid chromatography-mass spectrometry (HPLC-MS) showed that both naringenin and naringin formed mono-adducts and bis-adducts after reacting with methylglyoxal (MGO). Collectively, naringenin and naringin had good anti-glycation effects and inhibited AGEs through antioxidant action, thereby capturing intermediate products and chelating metal ions. These results indicate that naringenin and naringin can serve as safe and effective AGEs inhibitors with potential applications in food and medicine.

In order to improve the functional properties of Tenebrio molitor protein isolate (TPI) and to increase the feasibility of its application in the food industry, in this study, xylo-oligosaccharides (XOS) and Tenebrio molitor protein powder were used as raw materials to optimize the glycosylation reaction conditions, and the structural and functional properties of the Tenebrio molitor protein isolate glycosylated with xylo-oligosaccharides polysaccharide (TPIX) were investigeted. Taking the grafting degree and browning degree as evaluation indicators, the glycosylation conditions were screened through single-factor experiments. The structural properties of TPIX were analyzed by Fourier-transform infrared spectroscopy, endogenous fluorescence spectroscopy, and scanning electron microscopy. Functional properties, including foaming, emulsification, antioxidant activity, and in vitro digestibility, were also evaluated. The results showed that optimal glycosylation conditions were determined as follows: The mass ratio of TPI to XOS was 1:2, the pH was 9.0, the heating temperature was 85 ℃, and the heating time was 90 min. Under these conditions, the grafting degree and browning degree reached 32.24% and 0.078, respectively. Structural analysis confirmed significant conformational changes in TPI and XOS after glycosylation, along with a reduction in surface hydrophobicity, indicating the successful formation of the glycosylation product TPIX. Functionally, TPIX exhibited enhanced antioxidant activity, with DPPH, ABTS⁺ and hydroxyl radicals scavenging rates relatively increased by 57.85%, 74.17%, and 10.27%, respectively, compared with TPI under the same conditions. Foaming capacity and emulsifying activity were also significantly improved (P<0.05), although foaming stability, emulsifying stability and in vitro digestibility relatively decreased, by 62.1%, 40.08% and 13.39%, respectively. This study optimized the glycosylation reaction conditions between TPI and XOS. The resulting glycation products exhibited favorable foaming, emulsifying, and antioxidant properties, thereby providing a theoretical basis for the application of TPI in the food industry.

This study aimed to optimize the extraction process of Cistanche tubulosa polysaccharides (CP) and investigate their structural characteristics and anti-fatigue effects. Single-factor experiments combined with response surface methodology were employed to optimize extraction conditions with the polysaccharide yield as the evaluation index. Subsequently, CP was separated and purified through DEAE-52 cellulose column chromatography to obtain homogeneous polysaccharide fractions. On the basis of in vitro antioxidant activity screening, the structural properties were characterized via infrared spectroscopy, high-performance gel permeation chromatography, and ion chromatography, and animal experiments were performed to evaluate the anti-fatigue capacity of the optimal fraction. The results revealed that the optimal extraction parameters were 20 min of ultrasonication, a solid-to-liquid ratio of 1:20, and an ultrasonic power of 220 W, under which the maximum CP yield reached 8.55%. After purification, one neutral polysaccharide (CPN) and three acidic polysaccharides (CPA-1, CPA-2, CPA-3) were isolated. The yields of CPN, CPA-1, CPA-2, and CPA-3 were 40.3%, 22.6%, 13.7%, and 9.2% respectively, with their corresponding polysaccharide component recoveries being 78.3%, 89.6%, 65.4%, and 52.7%. The antioxidant activity of the four fractions followed the order: CPA-2>CPN>CPA-1>CPA-3. Given its high yield, favorable recovery efficiency and antioxidant activity comparable to CPA-2, CPN was selected for further investigation. Structural analysis confirmed that CPN possessed characteristic absorption peaks of polysaccharides, was mainly composed of glucose and mannose, and might contain two components with significantly different molecular weights. In vivo experiments demonstrated that CPN could significantly prolong the weight-bearing swimming time of mice, reduce the levels of blood urea nitrogen and blood lactic acid, and increase hepatic glycogen content, thereby verifying its anti-fatigue activity. These findings lay a solid foundation for the in-depth development and anti-fatigue application of Cistanche tubulosa polysaccharides.

This study aimed to improve the 3D printability of processed cheese by investigating the effects of different colloids (xanthan gum, guar gum, and curdlan) and addition level (0.1%~0.5%) on sample molding properties. Using Anchor processed cheese as the base material, processed cheese was prepared by incorporating edible colloids. The 3D printing performance rheological properties, thermal behavior, and microstructure were systematically characterized by using a rotational rheometer, differential scanning calorimetry, Fourier transform infrared spectroscopy, and scanning electron microscopy. Rheological results showed that all samples exhibited typical shear-thinning behavior. At a curdlan concentration of 0.4%, the sample reached an apparent viscosity of 40 Pa·s under a shear rate of 0.1 s⁻¹, and the storage modulus consistently exceeded the loss modulus, which indicated a dominant elastic response. 3D Printing tests demonstrated that samples with 0.4% curdlan exhibited the highest printing accuracy, structural stability (the morphology remained intact within 60 minutes), and structural integrity, which was significantly superior to other colloids systems. In summary, 0.4% curdlan could effectively enhance the 3D printing quality of processed cheese, providing a theoretical reference for 3D printing technology in dairy products.

The soybean peptide-starch complex was prepared using microwave-assisted treatment. The effects of microwave power levels at 350, 550, 700 and 1000 W on the interactions between soybean peptides and three types of starch—sweet potato, corn starch, and caltrop starch—were systematically investigated. The structure, physicochemical properties, and digestibility of the as-prepared complexes were explored. The results showed that compared with the physical mixture of starch, the soybean peptide-starch complex subjected to microwave treatment exhibited significant structural and functional changes. Scanning electron microscopy revealed the formation of a porous gel network along with aggregate structure, accompanied by a notable increase in particle size. X-ray diffraction and Fourier transform infrared spectroscopy (FT-IR) analyses demonstrated a reduction in crystallinity, characterized by a contraction of the crystalline peak at 1047 cm⁻¹/1022 cm⁻¹, while the amorphous region at 1022 cm⁻¹/995 cm⁻¹ remained relatively unchanged. Functionally, the complex displayed reduced gel strength and hardness, diminished anti-aging properties, yet improved freeze-thaw stability. In vitro digestion studies indicated that, compared to the physical mixture of soybean peptides and starch, the microwave-treated complex contained significantly lower levels of rapidly digestible starch. Notably, samples treated with 700 W microwave irradiation showed marked increases in both slowly digestible starch and resistant starch content, up to 28.20% and 35.70%, respectively. This study provides valuable insights into the development of soybean peptide-starch complexes and supports the potential application of modified starch as a hypoglycemic ingredient in food and frozen food products.