Search Results (34)

Off-odors produced by volatile compounds remain a major barrier to consumer acceptance of plant-based proteins. This study presents a novel two-stage fermentation strategy to effectively reduce undesirable volatiles in eight plant proteins. A sequential fermentation process was developed using Lactobacillus plantarum in Stage 1 and a traditional yogurt culture, Streptococcus thermophilus, Lactobacillus delbrueckii subsp. Bulgaricus and Lactobacillus acidophilus, in Stage 2. This method was applied to solutions of 9% soy, pea, chickpea, mung bean, faba bean, rice, barley-rice, and hemp proteins. Volatile profiles were analyzed via Selected Ion Flow Tube Mass Spectrometry (SIFT-MS) and sensory evaluation before and after fermentation. The two-stage fermentation resulted in significant deodorization, with 95–99% reduction in key odorants such as hexanal, 2-pentylfuran, methoxypyrazines, and sulfur compounds across all proteins. The sequential approach significantly outperformed a one-stage fermentation. Allulose enhanced L. plantarum activity while strawberry preserves supported traditional yogurt culture performance. Non-fermentable additives such as pectin, xanthan gum, and oil had minimal effects on volatiles. The proposed fermentation method offers an effective, scalable, and clean-label solution for mitigating off-odors in plant-based proteins. By leveraging microbial metabolism and formulation synergies, this strategy provides a foundation for developing more palatable plant-based dairy alternatives. Full article

Background/Objectives: This study evaluated the effects of a novel Astragalus extract (Keyfobell powder [KFB]) composed of Astragalus membranaceus, red ginseng (Panax ginseng C. A. Meyer), and Cervi Parvum Cornu as a potential growth hormone (GH) alternative. The primary focus was placed on its impact on longitudinal bone growth through the upregulation of circulatory insulin-like growth factor (IGF)-1. Methods: We performed in vitro and in vivo experiments using a hypothalamic cell line and Sprague–Dawley (SD) rats. Quantitative RT-PCR was performed to determine growth hormone-releasing hormone (GHRH) and ghrelin mRNA expressions in GT1-7 cells. The treatment groups were administered KFB at various dosages, and the positive controls received recombinant human GH. Body weight, bone length, and density were assessed, along with serum levels of insulin-like growth factor binding protein (IGFBP)-3 and IGF-1. Results: KFB and somatropin exhibited no cytotoxic effect in GT1-7 cells and increased GHRH and ghrelin mRNA levels in a dose-dependent manner. KFB administration resulted in a significant dose-dependent increase in body weight and bone growth (femur and tibia). Changes in IGF-1 and IGFBP-3 levels were comparable to those observed in the GH-treated group. Based on network pharmacological analysis, multiple compounds in KFB ((20S)-20-hydroxypregn-4-en-3-one, 2-isopropyl-3-methoxypyrazine, caproic acid, daidzein, furfuryl alcohol, lauric acid, octanal, and salicylic acid) may synergistically regulate the PI3K-Akt, Ras, and Rap1 signaling pathways linked to growth control and cartilage formation, leading to a possible increase in height. Conclusions: Our results suggest that KFB can function as a GH-mimetic agent that promotes bone growth through IGF-1 upregulation. Full article

In winemaking, the use of stems during fermentation is rarely employed due to some undesirable side effects. While the effect of fresh stems on wine is extensively studied, to date limited information is available about the effect of dried stems. This study aimed to investigate the impact of dried stems on the chemical and sensory profile of passito wines. Four withered grape varieties were selected for winemaking: three red and one white from the Verona area. Grapes were fermented with and without withered stems. A major impact on enological parameters, in particular pH and total polyphenols, was observed. In terms of volatile compounds, no release of C₆ alcohols—compounds with undesirable herbaceous odors—was detected. Varietal-dependent release of 3-isobutyl-2-methoxypyrazine (IBMP) was also observed; however in most cases, the content was below the odor threshold. Furthermore, dried stems significantly decreased methanethiol content, likely due to adsorption phenomena. Minor differences were observed in acetate esters, terpenes, and norisoprenoids, though these were not consistent across all wine types. From a sensory point of view, a significant variety-dependent effect was observed, mostly due to IBMP, ethyl acetate, and β-damascenone. Full article

This study employed the headspace-gas chromatography-ion migration spectrum (HS-GC-IMS) in conjunction with the gas chromatography-mass spectrometer (GC-MS) technique for the assessment of the flavor quality of complementary food powder intended for infants and young children. A total of 62 volatile compounds were identified, including aldehydes, esters, alcohols, ketones, pyrazines, and furans, among which aldehydes were the most abundant compounds. Based on the principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) models, infant nutritional powder (YYB) from different manufacturers could be clearly distinguished. Among them, 2-hydroxybenzaldehyde, 1, 2-dimethoxyethane, 2-isobutyl-3-methoxypyrazine, and methyl butyrate were the four most critical differential volatiles. In addition, these differences were also manifested in changes in fatty acids. The reason for this phenomenon can be attributed to the difference in the proportion of raw materials used in nutrition powder, micronutrient content, and the packaging process. In conclusion, this study provides comprehensive information on the flavor quality of YYB, which can be used as a basis for quality control of YYB. Full article

Low-temperature treatments preceding alcoholic fermentation are becoming increasingly popular and have been used in winemaking as a tool to improve wine colour, aroma, and quality. Additionally, the pre-fermentative treatment of grapes with cryogenic agents protects the grape juice (must) from oxidation by reducing the diffusion of atmospheric oxygen into the liquid phase during the winemaking process. Resultant wines were reported to have enhanced varietal aromas, increased complexity, and higher thiol levels. Indications are that increased contact time between skin and juice improves the extraction of the compounds and/or precursors. Recently, there has been considerable interest in the production of wines with enhanced varietal aromas and improved quality by applying innovative winemaking technologies. This review aims to provide an overview of the aroma and organoleptic quality of Sauvignon blanc and Chenin blanc wines produced from grapes that were subjected to pre-fermentative cryogenic treatments including the impact aroma compounds, i.e., volatile thiols and methoxypyrazines. Full article

In order to characterize red wine polymers with regard to their binding properties to aroma compounds (odorants), a qualitative and quantitative analysis of chemical degradation products after different chemical treatments (thiolytic, acidic, and alkaline depolymerization) of high -molecular-weight (HMW) fractions of red wine was performed. Using ¹H NMR, LC-ToF-MS, LC-MS/MS, and HPIC revealed key structural features such as carbohydrates, organic acids, phenolic compounds, anthocyanins, anthocyanidins, amino acids, and flavan-3-ols responsible for odorant-polymer interactions. Further, NMR-based interaction studies of the selected aroma compounds 3-methylbutanol, cis-whisky lactone, 3-methylbutanoic acid, and 3-isobutyl-2-methoxypyrazine with HMW polymers after chemical treatment demonstrated a reduced interaction affinity of the polymer compared to the native HMW fractions, and further, the importance of aromatic compounds such as flavan-3-ols for the formation of odorant polymer interactions. In addition, these observations could be verified by human sensory experiments. For the first time, the combination of a compositional analysis of red wine polymers and NMR-based interaction studies with chemically treated HMW fractions enabled the direct analysis of the correlation of the polymer’s structure and its interaction affinity with key odorants in red wine. Full article

The metabolic pathway of 3-alkyl-2-methoxypyrazines (MPs) in grape remains largely unclear except for the final step. In this study, the 2,5-dicarbonyl-3-isobutyl-piperazine (DCIP), which is proposed as the key intermediate of 3-isobutyl-2-methoxypyrazine (IBMP) biosynthesis, was incorporated into Cabernet Sauvignon clusters in situ using a soaking method. The IBMP concentration of grape and the expression patterns of VvOMTs in berry skin were monitored over two consecutive years. The results showed that the IBMP concentration of grape treated with DCIP was significantly increased at maturity in both years. The relative expression levels of VvOMT1 and VvOMT3 in berry skin were positively correlated with the IBMP accumulation. After DCIP incorporation, the relative expression level of VvOMT1 and particularly that of VvOMT3 were obviously up-regulated and closely mirrored the IBMP accumulation pattern in two consecutive years. Therefore, we speculate that DCIP may be a key intermediate involved in the biosynthesis of IBMP and plays an important role in regulating IBMP accumulation. Full article

Uniform grape maturity can be sought by producers to minimise underripe and/or overripe proportions of fruit and limit any undesirable effects on wine quality. Considering that grape heterogeneity is a multifaceted phenomenon, a composite index summarising overall grape heterogeneity was developed to benefit vineyard management and harvest date decisions. A grape heterogeneity index (GHI) was constructed by aggregating the sum of absolute residuals multiplied by the range of values from measurements of total soluble solids, pH, fresh weight, total tannins, absorbance at 520 nm (red colour), 3-isobutyl-2-methoxypyrazine, and malic acid. Management of grape heterogeneity was also studied, using Cabernet Sauvignon grapes grown under four viticultural regimes (normal/low crop load, full/deficit irrigation) during the 2019/2020 and 2020/2021 seasons. Comparisons of GHI scores showed grape variability decreased throughout ripening in both vintages, then significantly increased at the harvest time point in 2020, but plateaued on sample dates nearing the harvest date in 2021. Irrigation and crop load had no effect on grape heterogeneity by the time of harvest in both vintages. Larger vine yield, leaf area index, and pruning weight significantly increased GHI score early in ripening, but no significant relationship was found at the time of harvest. Differences in the Ravaz index, normalised difference vegetation index, and soil electrical conductivity did not significantly change the GHI score. Full article

In spite of its incidence on pistachio trees, the chemical ecology of Labidostomis lusitanica (Germar) (Coleoptera: Chrysomelidae) has been neglected so far. In this work, we provide the first evidence of a biologically active male-specific compound that may be promoting field aggregation. Headspace collections through solid-phase microextraction from feral males and females reported the presence of 2-isobutyl-3-methoxypyrazine exclusively in males. Electroantennographic recordings revealed that males and females responded in a dose-dependent manner to increasing stimuli of 2-isobutyl-3-methoxypyrazine, with females overall displaying a higher response than males. In dual-choice tests, both males and females showed a significant preference for the compound in comparison to a pure air stimulus. In light of these results, the possible role of 2-isobutyl-3-methoxypyrazine as an aggregation cue in L. lusitanica is discussed. Full article

To elucidate the effects of the different terroir on wine aroma in six sub-regions of Eastern Foothills of Helan Mountain in Ningxia, a premium wine-producing region in China, 71 Cabernet Sauvignon wines were investigated by gas chromatography-mass spectrometry (GC-MS), check-all-that-apply (CATA), and quantitative descriptive analysis (QDA). The bidirectional orthogonal partial least squares-discriminant analysis (O2PLS-DA) results showed that the Cabernet Sauvignon dry red wines from Xixia (XX) and Yongning (YN) had similar volatile profiles due to their geographical proximity and were characterized by higher concentrations of esters, higher alcohols, and volatile phenols because the similar aromatic profiles were detected in their dry red wines. Shizuishan (SZS) and Hongsipu (HSP) wines showed clear differences compared to the wines of the other four sub-regions, being mainly characterized by relatively higher phenolic aldehydes and volatile phenols. The concentrations of methoxypyrazines and norisoprenoids varied mainly depending on the climate diversity of the sub-regions. The highest 3-isobutyl-2-methoxypyrazine (IBMP) concentration was presented in the Helan (HL) wines. The Qingtongxia (QTX) wines have the highest β-damascenone, which might be influenced by the fact that QTX has the lowest effective accumulated temperature and the highest sunshine duration among the five sub-regions. Esters including ethyl octanoate, ethyl decanoate, ethyl butanoate, ethyl hexanoate, and isoamyl acetate were the highest in HL. Additionally, the herbaceous, black berry, and red berry notes in HL and QTX were the most outstanding. Full article

Key varietal characteristics of Sauvignon Blanc, including the descriptors of ‘green’ and ‘tropical fruit’, are mostly attributed to methoxypyrazines and volatile thiols, while monoterpenes, higher alcohols, esters, fatty acids, and other volatile compounds also add complexity and fruity notes to the wines. During the winemaking and ageing period, oxidation decreases the concentrations of these compounds and diminishes the flavours derived from this aromatic grape variety. Therefore, antioxidants, such as sulfur dioxide, are commonly utilized in Sauvignon Blanc wine production for better preservation of those beneficial primary aromas. This review focuses on key varietal aromas in Sauvignon Blanc wine and how they are influenced by oxidation, and SO₂ alternatives, including ascorbic acid, glutathione, and glutathione-enriched inactivated dry yeasts, that can be used in winemaking as antioxidants. Full article

Parallel extraction of headspace volatiles from multiwell plates using sorbent sheets (HS-SPMESH) followed by direct analysis in real-time high-resolution mass spectrometry (DART-HRMS) can be used as a rapid alternative to solid-phase micro-extraction (SPME) gas-chromatography mass-spectrometry (GC-MS) for trace level volatile analyses. However, an earlier validation study of SPMESH-DART-MS using 3-isobutyl-2-methoxypyrazine (IBMP) in grape juice showed poor correlation between SPMESH-DART-MS and a gold standard SPME-GC-MS around the compound’s odor detection threshold (<10 ng/kg) in grape juice, and lacked sufficient sensitivity to detect IBMP at this concentration in grape homogenate. In this work, we report on the development and validation of an improved SPMESH extraction approach that lowers the limit of detection (LOD < 0.5 ng/kg), and regulates crosstalk between wells (<0.5%) over a calibration range of 0.5–100 ng/kg. The optimized SPMESH-DART-MS method was validated using Cabernet Sauvignon and Merlot grape samples harvested from commercial vineyards in the central valley of California (n = 302) and achieved good correlation and agreement with SPME-GC-MS (R² = 0.84) over the native range of IBMP (<0.5–20 ng/kg). Coupling of SPMESH to a lower resolution triple quadrupole (QqQ)-MS via a new JumpShot-HTS DART source also achieved low ng/kg detection limits, and throughput was improved through positioning stage optimizations which reduced time spent on intra-well SPMESH areas. Full article

Grape volatile compounds directly determine the aroma quality of wines. Although the aroma profile of grapes evolved greatly at different maturity stages, there were less considerations for aroma status when determining grape harvest time. In the present study, several maturation indicators, namely, sugars/acids ratio, free volatile compounds, bound volatile compounds and IBMP (3-isobutyl-2-methoxypyrazine) content were monitored in four red wine grape varieties (Vitis vinifera L. cv Cabernet Sauvignon, Cabernet Gernischet, Cabernet Franc and Merlot) near harvest time (42 days) in Ningxia, China. The results showed that the highest sugars/acids ratio was reached on day 21 and day 28 for Merlot and the other three varieties, respectively. For both free and bound volatile compounds, the content of carbonyl compounds decreased continuously in the process of ripening. The contents of free alcohols, esters and terpenes increased in the ripening stage and decreased in the stage of over-ripening. The accumulation of favorable bound aroma compounds peaked at day 35. The content of IBMP presenting a green smell in all four varieties descended continuously and kept steady from day 28. Therefore, the present findings revealed that the best aroma maturity time of four studied grape varieties was later than the sugars/acids ratio in Ningxia region. Aroma maturity should be taken into account during harvest time determination. Full article

Grapevine red blotch disease (GRBD) has negative effects on grape development and impacts berry ripening. Abscisic acid (ABA) is a plant growth regulator involved in the initiation of berry ripening. Exogenous abscisic acid application was compared to an unsprayed control on GRBD-positive Pinot noir vines during two vintages, and the total monomeric anthocyanin, total phenolics, phenolic composition, and volatile profile were measured in wines. In addition, untargeted metabolites were profiled using high-resolution LC-MS/MS. Results showed that the wine composition varied by vintage year and was not consistent with ABA application. Wines from the ABA treatment had a lower total anthocyanin and total phenolic content in one year. The untargeted high-resolution LC-MS/MS analysis showed a higher abundance of phenolic compounds in ABA wines in 2019, but lower in 2018. The wine volatile compounds of ABA treatments varied by vintage. There were higher levels of free β-damascenone, β-ionone, nerol, and several fermentation-derived esters, acids, and alcohols in ABA wines, but these were not observed in 2019. Lower 3-isobutyl-2-methoxypyrazine (IBMP) was also observed in wines with ABA treatment in 2019. The results demonstrated that ABA application to the fruit zones did not consistently mitigate the adverse impacts of GRBD on Pinot noir wines. Full article

Grapes are one of the most valuable fruit crops in the United States and can be processed into a variety of products. The grape and wine industry contributes to and impacts the U.S. agricultural economy. However, rising labor costs and global competition pose challenges for the grape and wine industry. Vineyard mechanization is a promising strategy to increase efficiency and address the labor shortage and cost issues. Recent studies have focused on the impact of vineyard mechanization on general grape and wine quality. Wine phenolics, aroma compounds, and sensory characteristics are the key indicators of wine quality and consumer preference. This article aims to review the impact of vineyard mechanization, specifically mechanical harvesting, mechanical leaf removal, mechanical shoot thinning, cluster thinning, and mechanical pruning on grape and wine phenolics, and aroma compounds and sensory profile. Studies have shown that vineyard mechanization significantly affects phenolic and aroma compounds, especially grape-derived aroma compounds such as volatile thiols, terpenes, C13-norpentadiene, and methoxypyrazine. Mechanically processed grapes can produce wines of the same or better quality than wines made from hand-operated grapes. Vineyard mechanization could be a promising strategy for grape growers to reduce operating costs and maintain or improve grape and wine quality. Future research directions in the area of vineyard mechanization were discussed. It provides a comprehensive view and information on the topic to both grape growers and winemakers in the application of vineyard mechanization. Full article