International audience | An innovative chemometric method was developed to exploit visible and near-infrared (Vis-NIR) spectroscopy to guide food formulation to reach the anticipated and constant quality of final products. First, a total of 671 spectral variables related to the puree quality characteristics were identified by spectral variable selection methods. Second, the concentration profiles from multivariate curve resolution-alternative least squares (MCR-ALS) made it possible to reconstruct the identified spectral variables of formulated purees. Partial least square based on the reconstructed Vis-NIR spectral variables was evidenced to predict the final puree quality, such as a* values (RPD = 3.30), total sugars (RPD = 2.64), titratable acidity (RPD = 2.55) and malic acid (RPD = 2.67), based only on the spectral data of composed puree cultivars. These results open the possibility of controlling puree formulation: a multiparameter optimization of the color and taste of final puree products can be obtained using only the VisNIR spectral data of single-cultivar purees.

Lily bulbs are valued for their health benefits, and drying is a common method for their preservation. This study employed untargeted metabolomics using UHPLC-QTOF-MS to analyze the phytochemical profiles of lily bulbs dried by hot air (HD), microwave (MD), and vacuum freeze (FD) methods. In terms of appearance, FD samples exhibited minimal browning and wrinkling, while HD bulbs showed the most severe changes. Nineteen potential markers were identified, with HD samples showing higher levels of bitter amino acids, peptides, and N-fructosyl phenylalanine. The markers of FD samples were glutamine, coumarin, and p-coumaric acid. Notably, eleutheroside E was detected in lily bulbs for the first time and confirmed as an MD marker, with levels 1.51-fold and 6.19-fold higher than in FD and HD samples, respectively. MD method shows promise for enriching bioactive compounds in dried lily bulbs.

Given the side effects associated with synthetic antihypertensive drugs, there is a growing need among researchers to investigate angiotensin-converting enzyme (ACE) inhibitory peptides derived from food protein as safer therapeutic alternatives. This study used seabuckthorn (Hippophae rhamnoides L.) seed meal as the raw material, and the protein was extracted by alkaline extraction and acid precipitation. After enzymatic digestion, peptides with molecular weight less than 3 kDa were selected for study. The screened peptide had an IC50 value of 4.358 mg/mL on ACE with a non-competitive inhibition mechanism and good inhibition stability. By employing infrared (IR) analysis, exclusively β-fold and β-helix structures were identified in the hydrolysate, while no other structural motifs were detected. X-ray diffraction revealed that it had an irregular amorphous structure. The peptide contains 17 amino acids that are both highly acidic and hydrophobic, with glutamic acid ranking first in terms of the number of individual amino acids. Compared with the database (NCBI, Uniport), ten peptides with ACE inhibitory activity were detected, and molecular docking showed the mechanism of each peptide inhibiting ACE, FRVAWTEKNDGQRAPLANN, LIISVAYARVAKKLWLCNMIGDVT-TEQY, VIRSRASDGCLEVKEFEDIPP, AGGGG-GGGGGGSRRL, LQPREGPAGGTT-ALREELSLGPEAALDTPPAGP, DDEARINQLFL, FAVSTLTSYDWSDRDDATQGR-KL, RQLSLEGSGLGVEDLKDN, GGGGGGGGGGGGGGGIGGGGGGGGGGGAR, and KEALGEGCFGNRIDRIGD. According to the results, AGGGGGG-GGGGSRRL is more stable in binding to ACE and may have better inhibitory activity. It has been shown that seabuckthorn protein can be an alternative source of ACE inhibitory peptides.

In this study, three representative pears ('Yali' Pear, 'Huangguan' Pear, and 'Xuehua' Pear) peel/flesh polyphenol extracts were characterized by their antioxidant activity, polyphenol composition, and in vitro cholesterol/cholates binding capacity. 'Yali' Pear polyphenol extracts were selected to further investigate the mechanism of in vitro cholesterol/cholates lowering capacity. Lagergren adsorption kinetic and Freundlich isotherm models confirmed the occurrence of this combination. Turbidity, average particle size, transmission electron microscopy, and zeta potential combined confirmed the existence of some interaction between polyphenols and cholesterol/cholates. Cholesterol/cholates quenched the exogenous fluorescence of polyphenols by static mechanism. The thermodynamic interaction results revealed that the interaction between polyphenols and cholesterol is a spontaneous process, primarily driven by hydrogen bonding and hydrophobic interactions. Overall, this study aimed to investigate the confirmation of the binding removal properties of pear polyphenols on cholesterol/cholates to mitigate the adverse health effects of a high-fat diet.

Saccharomyces cerevisiae is the earliest domesticated fungus, researched deeply and widely used fungus. When used in food fermentation, Saccharomyces cerevisiae has an important influence on the quality, flavor, and aroma of products. Future developments will focus on enhancing flavor diversity, increasing production efficiency, sustainability, and product consistency, as well as improving the fermentation characteristics by using advanced technologies. Saccharomyces cerevisiae is an ideal substrate for synthetic biology research, usually used in the production of lactic acid, terpenes, steroids, vaccines, etc., which helps to reduce production cost, shorten the production cycle, improve production capacity, and has a very broad application prospect. In addition, in the field of environmental protection, biofuel ethanol is one of the promising and popular fuels with potential for energy and environmental security. However, there are major challenges for Saccharomyces cerevisiae that use lignocellulosic biomass as feedstock to produce biofuel ethanol.

As a superfruit, wolfberry has extremely high nutritional value, and how to enhance the accessibility of its nutrients is the core of current research. This study focused on exploring the kinetic model of Lactobacillus plantarum CCFM1050 fermentation of wolfberry and the potential alterations of antioxidant activity and volatile flavor compounds induced by lactic acid fermentation. we monitored cell counts, product formation, and substrate changes over a 72-h period of wolfberry fermentation. A kinetic model was developed to illustrate cell growth, substrate consumption, and product accumulation during wolfberry pulp fermentation. Phenolic substance analysis revealed a significant increase in total phenol and flavonoid content in wolfberry pulp during fermentation, reaching 1.16 and 1.15 times, respectively, compared to pre-fermentation levels. The elevated levels of phenolic substances led to a substantial increase in DPPH and ABTS free radical scavenging rates in fermented wolfberry pulp, reaching 67.16% and 32.10%, respectively. Volatile components of samples were analyzed using the HS-GC-IMS method, and fingerprints of wolfberry pulp before and after fermentation were established. A total of 51 compounds were identified, including 12 alcohols, seven aldehydes, two acids, eight esters, and 12 ketones, contributing to an enhanced flavor profile in the fermented wolfberry pulp. This study is helpful for understanding the kinetic changes in the lactic acid fermentation of wolfberry, the changes of antioxidant active substances and VOCs, and provides guidance for the industrial processing of wolfberry.

Carboxypeptidase A(CPA) has a great potential application in the food and pharmaceutical industry due to its capability to hydrolyze ochratoxin A(OTA) and remove the bitterness of peptide. However, CPA is a mesophilic enzyme that cannot adequately exert its catalytic activity at elevated temperatures, which seriously restricts its industrial application. In this study, the rational design of disulfide bonds was introduced to improve the thermostability of CPA. The highly flexible regions of CPA were predicted through the HotSpot Wizard program and molecular dynamics (MD) simulations. Then, DbD and MODIP online servers were conducted to predict potential residue pairs for introducing disulfide bonds in CPA. After the conservativeness analysis of the PSSM matrix and the structural analysis of the MD simulation, two mutants with potentially enhanced thermostability were screened. Results showed that these mutants D93C/F96C and K153C/S251C compared to the wild-type(WT) exhibited increase by 10 and 10 °C in Topt, 3.4 and 2.7 min in t1/2 at 65 °C, in addition to rise of 8.5 and 11.4 °C in T5015, respectively. Furthermore, the molecular mechanism responsible for thermostability was investigated from the perspective of advanced structure and molecular interactions. The enhanced thermostability of both mutants was not only associated with the more stable secondary structure and the introduction of disulfide bonds but also related to the changes in hydrogen bonds and the redistribution of surface charges in mutant regions. This study showed for the first time that the rational design of disulfide bonds is an effective strategy to enhance the thermostability of CPA, providing in this way a broader industrial application.

Fresh walnuts (Juglans regia L.) are challenging to store due to their high water content and delicate green appearance. It has been reported that sodium nitroprusside (SNP, a nitric oxide donor) can promote stress tolerance. However, whether SNP affects the postharvest quality of fresh walnuts remains unknown. This research showed that appropriate SNP treatment contributed to walnut preservation; in particular, 0.5 mmol/L SNP treatment resulted in a better appearance and less decay (59.7%). Compared with the control, this treatment not only increased the levels of proteases related to fresh walnut disease (chitinase and β-1,3-glucanase) but also increased the overall antioxidant level and reduced oxidant damage. Moreover, respiratory metabolism and ethylene release were greatly suppressed (9.5%), and the overall sensory evaluation did not reveal any adverse effects associated with a lower acid or peroxide content. Thus, it was inferred that the optimal SNP dose activated disease-related enzymes, mediated the physiological metabolism rate, regulated the ROS-redox balance and therefore reduced decay and maintained the walnut quality. This is the first report of SNP (NO) application for the preservation of fresh walnuts and may provide information to facilitate practical application of this potential innovation.

Vibrational spectroscopy is a green, rapid, and affordable analytical tool for analysing the quality, safety, and origin of biological materials in agri-food sectors. Pre-processing spectral data is crucial to removing instrumental interferences and physical artifacts when developing a classification model. However, there has yet to be a consensus on which spectral pre-processing method, settings, and decision parameters to use to optimise pre-processing for different spectroscopy tools. Using an arbitrary criterion poses a risk of applying the wrong type or too severe pre-processing that removes valuable information or affects the model's performance for prediction studies. Matthew's Correlation Coefficient (MCC) - a statistic for parameterising classification performance, accounts for data set imbalance and improved decisions on model selection to express uncertainty on future predictions. Four vibrational spectroscopy instruments [near-infrared (NIR), hyperspectral (HSI), mid-infrared (FTIR), and Raman] were compared using different pre-processing methods to understand the performance using MCC to classify coffee from four countries (Indonesia, Ethiopia, Brazil and Rwanda). Key decision parameters were evaluated for the development of reliable classification models. The best pre-processing for NIR was extended multiplicative scatter correction with mean centering (MNCN), and for HSI, Savitzky-Golay (1st derivative, 15 points) with MNCN. NIR performed the best across all four instruments, with FTIR performing the worst. Raman showed potential for coffee origin classification using the right pre-processing. Pre-processing with weighted least squares, normalisation, and MNCN eliminated the fluorescence effect on Raman spectral data. These findings show the feasibility of using MCC for classification problems.