Food Chemistry: X最新文献

The smoky scent is the most distinctive feature for Souchong black tea. To reduce the dependence on pinewood in the smoking process of Souchong black tea, it is crucial to find an effective alternative smoking material. Five black tea samples were prepared via using specially designed fuel rods as the smoking material in this study. Sensory analysis showed that DS (smoking at the drying stage) had the most favorable aroma, featuring a pleasant smoky aroma with floral and fruity notes. 69 volatile compounds were detected in five tested samples. Key volatiles such as β-caryophyllene, nerolidol, guaiacol, and α-terpineol, known for their woody or smoky aroma, were prominent in both DS and TS (the traditional Lapsang Souchong process) samples (OAV > 1, VIP > 1 and P < 0.05). However, DS exhibited significantly lower concentration of these volatiles than TS, giving it a more pleasant aroma. Additionally, phenylethyl alcohol and α-farnesene were characteristic volatiles in FS (smoking at the fermentation stage) and DS, imparting a sweet, mildly smoky aroma. Therefore, using these specialized fuel rods to smoking process at drying stage is an optimal method for processing Souchong black tea. These findings provide a theoretical foundation for stabilizing Souchong black tea quality, promoting green and low-carbon tea production methods.

This study used integrative omics to address the response of key elements of the grapevine holobiont to contrasted pedoclimatic conditions found in distinct subregions of Douro Valley (Portugal). A metabolic OPLS-DA model predicted with 100 % accuracy the geographic origin of berries; higher UV radiation, higher temperature and lower precipitation stimulated the accumulation of phenolic acids, flavonols and malvidin conjugates, in detriment of amino acids, organic acids, flavan-3-ols, proanthocyanidins and non-malvidin anthocyanins. Metabarcoding showed a trade-off between bacteria and fungal diversity among subregions, with Pseudomonas, Lactobacillus, Aspergillus and Penicillium acting as intraregional microbial markers. The high phenotypic plasticity of berries and the role of microbes in this process are relevant upon current projections for increased UV radiation and temperature in Southern European viticulture, in a climate change scenario, with predicted impacts on regional wine quality and on the development of adaptation strategies for resilient viticulture.

The objective of this study was to substitute partially fat with pea protein isolate (PP)/rutin (Ru) complexes to produce a healthy and stable low-fat whipped cream. Ru enhanced the foam properties of PP. The Ru binding equivalent was the best at a mass ratio of PP/Ru of 64:4, the PP/Ru complexes particle size was the smallest. The synergistic adsorption of Ru reduced the interfacial tension of the complexes and accelerated their diffusion, permeation, and rearrangement at the air/water interface. The results of rheology and Lissajous plots suggested that PP/Ru complexes functioned as an interfacing stabilizer, enhanced the elastic strength of interface film, and improved the stability of foam. PP/Ru complexes as a fat substitute promoted the aggregation of fat globules and the formation of fat globule network structure. When the substitution rate is 10 %, the texture, stability, and microstructure of the sample are nearly identical to those of full-fat cream.

The anthocyanin-loaded films based on natural polymers as pH-responsive indicator are widely applied in the food preservation. However, the low mechanical strength and storage stability limited their practical application, there is an urgent demand to improve the performance of anthocyanin-loaded films. In order to avoid affecting the color indication of anthocyanins, we explored the effect of eight kinds of white nanomaterials on improving the performance of films. The results revealed that some nanomaterials showed capability in improving the polymer molecular interactions and enhancement in mechanical properties, barrier ability, and antioxidant activity. However, nanomaterials containing Zn was not suitable for anthocyanin-loaded film modification, because it could destroy the pH responsiveness of anthocyanin. The nano Al₂O₃ could increase the sensitivity of anthocyanin-loaded film in pH-response, which achieved the highest performance score during pork storage. This investigation will provide theoretical support for the development of more optimized pH-responsive anthocyanin-loaded films in the future.

The properties, applications, and in vitro bioactivities of turmeric, turmeric essential oil (TEO), and turmeric essential oil by-products (TEO-BP) were evaluated using sensory analysis, gas chromatography-mass spectrometry (GC-MS), gas chromatography-ion mobility spectrometry (GC-IMS), and electronic nose techniques. A total of 62 and 66 volatile organic compounds (VOCs), primarily terpenoids and sesquiterpenoids, were identified by GC-MS and GC-IMS, respectively. Distillation temperature, particularly at 90 °C, significantly influenced the color and organoleptic properties of TEO, with variations in VOC profiles driving these differences. Molecular distillation at 90 °C was found to optimize the purification and concentration of key VOCs in TEO. All turmeric samples demonstrated robust antioxidant and α-glucosidase inhibitory activities, with TEO-90 exhibiting the highest bioactivity. These results underscore the potential applications of TEO and TEO-BP in food and nutraceutical industries, offering a sustainable strategy to reduce waste and enhance the efficient utilization of turmeric resources.

The quality and flavor of Liuyang Douchi are usually closely related to the metabolites compostion. This work described the metabolic profiles of Liuyang douchi during fermentation. Obvious hydrolysis of carbohydrates, proteins and slight lipids degradation were observed. Notably, the qu-making and pile-fermentation stage of douchi could be easily distinguished according to their metabolites profile, and pile-fermentation stage showed the most abundant metabolites. Specifically, organic acid, such as succinic acid and lactic acid, accumulated during pile-fermentation, as well as amino acids and derivatives. Especially glutamate (Glu), which contributed to the umami taste, increased form 0.82 mg/g to 15.90 mg/g after fermentation. Meanwhile, metabolisms related to amino acids were also the main enrichment metabolic pathways. Among them, some flavor compunds such as phenylacetaldehyde might drived from phenylalanine metabolism. These results could provide a new understanding on the metabolic characteristics during Liuyang douchi fermentation.

Developing a robust and safe carrier for enzyme immobilization is crucial for their application in the food processing industry. In this study, a novel crosslinked chitosan microspheres (CSMs) were prepared using glutaraldehyde (GA) as the crosslinking agent, using a newly developed emulsification-neutralization combined method. Nuclease P1 (NP1) was immobilized onto these microspheres, the maximum activity of NP1@CSMs-GA reach to 53,859.4 U/g. The activity recovery yield reach to 75 %. Compared to the free NP1, the stability of NP1@CSMs-GA was significantly enhanced. Its v_max and K_m is 895.71 mg/(g·min) and 77.27 mg/mL respectively. This NP1@CSMs-GA was utilized in production of nucleotides through hydrolysis of RNA. In BSTR, NP1@CSMs-GA retained more than 75.1 % initial activity after 10 cycles of reuse. Moreover, in PBR, the RNA hydrolysis conversion rate maintained 81 % after 24 h of continuous operation. These results demonstrate that NP1@CSMs-GA exhibits excellent reusability and production stability in practical processes.

The effects of storage on rice flavor among different rice varieties have not been well studied. To address this gap, we analyzed volatile organic components (VOCs) identified by gas chromatography-ion mobility spectrometry (GC-IMS) and related physicochemical properties of different storage-tolerant rice varieties during storage. The results showed that VOCs of four rice varieties significantly changed after 6 months of storage; OPLS-DA analysis classified the four rice varieties into two groups. There were fewer (N81 and JH1) and more significant changes (N84 and ZJ96) after storage, and the hexanal and 2-pentylfuran were considered the key VOCs for flavor changes during storage. Lipoxygenase (LOX) activity first increased and then decreased, while antioxidant activities decreased during storage. Under these conditions, oleic and linoleic acids were hydrolyzed. These results provide a better understanding of rice flavor changes after storage between different storable rice varieties.

To investigate the impact of genetic factors on wine aroma, wines made from 22 clones of five grape varieties (Vitis vinifera L.) were used to analyze the volatile compounds by headspace solid phase microextraction gas chromatography mass spectrometer (HS-SPME-GC-MS) and headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS). Results showed that 52 and 49 aroma compounds were identified from 22 clones of wines by two technologies, respectively. Esters were the most abundant compounds, followed by alcohols and aldehydes. The aroma profiles demonstrated significant varietal and clonal diversity, the clones with the highest aroma compound content were CH VCR6, PN VCR20, CS VCR11, ML VCR101, and CF 678. Partial least squares discriminant analysis (PLS-DA) identified decanoic acid, 1-heptanol, diethyl succinate, ethyl octanoate, and octanal as key biomarkers for distinguishing 22 clones of wines. Our results revealed that white wine CH VCR6 and red wine CS VCR11 possessed the most complex aromas. These findings address the research gap concerning the genetic determinants of wine aroma, highlighting the significance of grape variety and clone selection in developing wines with desirable sensory attributes.

This study sought to investigate the thermal stability and digestibility of corn starch sugar residue resistant starch (CSSR-RS) through comparative analysis of the physicochemical properties and structural characteristics among CSSR-RS, high-amylose corn starch (HS), and normal corn starch (NS). CSSR-RS contained 51.76 % resistant starch (RS), with 42.6 % remaining after high-temperature treatment, which was significantly higher than HS, demonstrating strong resistance to gelatinization. CSSR-RS is characterized by highly ordered aggregation of small molecules with a C-type crystalline structure, and irregular granular structures with wrinkled surfaces. Compared with NS and HS, the short-range and long-range order of CSSR-RS were significantly higher, indicating excellent thermal stability. In vitro simulated digestion revealed that the total hydrolysis rate of CSSR-RS was significantly lower than those of NS and HS, and the residual digesta of CSSR-RS also showed better resistance to digestion than HS. CSSR-RS exhibited significant development prospects in healthy food.