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.

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.

Cyclodextrins are tapered cyclic oligosaccharides, which are used to encapsulate a wide range of compounds, such as phytochemicals and drugs. They can be divided roughly into native, modified, and large-ring cyclodextrins: native- and large-ring cyclodextrins are prepared from starch by cyclodextrin glycosyltransferase and are further chemically modified, improving their chemical properties, such as water-solubility. Cyclodextrins have many possible applications in food processing due to their inclusion complexation characteristics. Cyclodextrins can be used to improve the color properties of food by protecting natural pigments from degradation during storage or by inhibiting enzymatic browning. In addition, encapsulation of bitter compounds inhibits their interactions with taste receptors in the oral cavity, decreasing undesirable taste properties. Finally, encapsulation of hydrophobic compounds improves their dispersion in the aqueous matrix, increasing the bioavailability and antioxidative activity of the target compounds. Studies have shown that successful use of the cyclodextrin requires good planning and understanding of the chemical composition of the food product.

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.

The peel of pitaya fruit is a promising source of pectin, and non- or low-methylesterified pectin has multiple bioactivities and application scenarios. In this study, non-methylated pectin was prepared from pitaya peel and the structure was characterized. Single factor experiment and response surface methodology were conducted to optimize the procedure of ultrasonic-assisted extraction for pectin. Under the optimal conditions (solid-liquid ratio of 1:40 g·mL−1, extraction temperature at 56 °C, extraction time of 25 min and ultrasonic power of 200 W), the pectin yield was up to 9.93% ± 0.97%. Degree of methylesterification and FTIR analysis confirmed that the extracted pectin was almost non-methylesterified. The pectin possessed less linear homogalacturonan (HG) but more rhamnogalacturonan (RG) regions according to the molar ratios of monosaccharides. Meanwhile, the molecular weight of the pectin was 33.52 kDa and the crystalline index was only 0.60%. Furthermore, the nanoscale structure observed by atomic force microscopy showed that the pectin was rich in highly branched polymers. Generally, pitaya peel pectin extracted by ultrasonic-assisted extraction showed a wide range of potential use as a non-or low- methylesterified pectic substance to reach the efficient utilization of fruit waste.

Investigating the influences of different sterilization methods on overall juice quality is essential for the production of high-quality juice. The effects of ultra-high temperature instantaneous sterilization (UHT), thermosonication (TS), high hydrostatic pressure sterilization (HHP), and irradiation sterilization (IS) on the physicochemical properties, functional components, and color of Aronia melanocarpa juice (AMJ) were investigated. In addition, anthocyanin target metabolomics were used to explore the influences of different sterilization methods on the AMJ anthocyanin profile. All sterilization treatments effectively ensured the microbial safety of AMJ, and the AMJ viscosity was noticeably declined after sterilization (p < 0.05). Except for HHP, the other treatments aggravated AMJ browning (p < 0.05). Both TS and HHP treatments significantly enhanced or preserved the total polyphenols, flavonoids, and anthocyanins in AMJ and retained the original juice color, whereas UHT and IS treatments were not conducive to maintaining these characteristics. TS treatment significantly increased cyanidin-3-O-galactoside (C-3-O-gal) and cyanidin-3-O-arabinoside (C-3-O-ara) contents in AMJ by 7.98% and 5.90%, while IS resulted in a significant decrease of 15.74% and 10.46% (p < 0.05). C-3-O-gal and C-3-O-ara were the major reasons for the significant upregulation and downregulation of the total monomeric anthocyanins contents (TMAC) in the AMJ after TS and IS treatment, respectively. Malvidin-3-O-glucoside (M-3-O-glu), Cyanidin-3-O-(6-O-malonyl-β-D-glucoside) and Kaempferol-3-O-rutinoside (K-3-O-rut) might be markers of differential metabolites produced by the TS, HHP, and IS treatments, respectively. Correlation analysis indicated that Cyanidin-3-O-xyloside (C-3-O-xyl), C-3-O-ara, and Pelargonidin-3-O-arabinoside (P-3-O-ara) might be the principal contributed to the antioxidant capacity of AMJ. The research results are anticipated to supply technical reference for AMJ processing.

Studying the metabolic patterns underlying the key quality traits during the growth and development of melon is very important for the quality improvement and breeding of melon fruit. In this study, we employed transcriptomics and metabolomics to analyze the primary metabolic changes occurring in melon ('Xizhoumi 25') across five growth and development stages. We identified a total of 666 metabolites and their co-expressed genes, which were categorized into five different metabolic and gene modules. Through the analysis of these modules, the main metabolic pathways during the growth and development of melon were demonstrated from a global perspective. We also discussed the contribution of sucrose accumulation, the TCA cycle, and amino acid metabolism to the quality and flavor of melon. Enzymes related to amino acid metabolism were proposed, including Amine oxidase (AOC), aldehyde dehydrogenase (ALDH), tryptophan synthase (TRPB), etc. These results and data can provide new insights for further study on the metabolic regulation of melon quality and improve fruit quality.

Cork taint has devastating effects on the aroma and quality of the wine, which can cause an annual loss of may be up to more than one billion dollars. There are many causes of cork taint, but 2,4,6-trichloroanisole (2,4,6-TCA) is a major contributor, giving the wine a wet-moldy smell. This study provided a comprehensive overview of the occurrence, detection, and control/remediation of 2,4,6-TCA. The occurrence and formation mechanisms of 2,4,6-TCA mainly include microbial O-methylation of chlorophenols and chlorination of anisole. The source of 2,4,6-TCA in wine is the cork or other woodworks, but it is also possible to contaminate wine from the environment. Due to the extremely low odor threshold concentration of 2,4,6-TCA, the effective sample pre-enrichment for instrument identification and quantification is more important. The control/remediation strategies of 2,4,6-TCA mainly include eliminating 2,4,6-TCA in cork and removing 2,4,6-TCA from wine by adsorption. Finally, the challenges and possible future research directions in this research field were discussed and proposed.

The toxicity of ginkgo kernel is a global concern, restricting its consumption as a medicinal food. This study focuses on eliminating the toxic components, specifically ginkgolic acid, from ginkgo kernel juice. The approach used was probiotic fermentation with autochthonous lactic acid bacteria combined with macroporous resin. Compared to using lactic acid fermentation alone, adding macroporous resin during probiotic fermentation significantly enhanced the removal of toxic ginkgolic acid and 4'-O-methylpyridoxine from ginkgo kernel juice. After 48 h of fermentation with macroporous resin, the contents of ginkgolic acid and 4'-O-methylpyridoxine decreased by more than 69% and 61%, respectively. Interestingly, the adsorption of microbial growth inhibitors, such as ginkgolic acid, 4'-O-methylpyridoxine, and phenolics, by the resin did not hinder the growth of lactic acid bacteria or their metabolic activities involving organic acids and monosaccharides. The study further confirmed that microbial adsorption was the primary reason for removing ginkgolic acid during probiotic fermentation. Also, the adsorption mechanism of ginkgolic acid during probiotic fermentation with macroporous resin was explored. From a mass transfer perspective, incorporating macroporous resin during the probiotic fermentation of ginkgo kernel juice reduced the mass transfer resistance for surface diffusion. Consequently, this lowered the contribution of surface diffusion to the overall diffusion process and facilitated the efficient removal of toxic ginkgolic acid. This work can help to understand the physical mechanism regarding detoxification of ginkgo kernel juice by probiotic fermentation, and offer potential strategies to enhance the safety of ginkgo kernel products.

Color is a crucial sensory indicator of wine quality. However, changes in anthocyanin concentration and profile occur during wine aging, resulting in noticeable reductions in chroma and shifts in hue from purple to brick red. This is because monomeric anthocyanins degrade and derivative anthocyanins form. The rate of color changes can vary depending on complex factors, such as the anthocyanin content of the must, oenological technology, and environmental conditions, which makes the management of red wine color evolution challenging. To address this issue, appropriate winemaking techniques are required to achieve an elegant wine color. This review summarizes the mechanisms related to anthocyanin stability, including glycosylation, acetylation, and derivatization. The review also discusses factors influencing red wine color fading for specific grape varieties and wine appellations, offering time- and cost-efficient techniques to accelerate anthocyanin derivatization and color stabilization.