Specific Aroma Research Articles

Contribution of terpenes, methanethiol, and fermentative esters to sparkling wine aroma in relationship to production technology, vintage, and aging: a case study on Durello wines.

This study aims at assessing the chemical and sensory variability existing across sparkling white wines of a single appellation in relationship to production technique and aging, identifying the existence of specific aroma chemical and sensory (odor) signatures. For this purpose, we selected Durello, an emerging sparkling white wine from Veneto region produced using either Charmat or Classico methods. Comparison of Durello varietal volatiles profile with other Italian sparkling and still wines highlighted specific features of Durello such as high content of 1,4-cineole and non-megastigmane norisoprenoids. Production technique (Charmat or Champenoise) impacted both the volatile chemical profile, influencing the content of esters, fatty acids, cyclic terpenoids, C6 alcohols, β-damascenone and methanethiol. With regard to wine age and vintage, an influence on esters, p-menthane-1,8-diol, cineoles and methyl salicylate was observed. Sensory evaluation by means of a sorting task approach indicated the existence of two main types of odor profile, one clearly associated with Classico method. The main drivers of such aroma diversity were esters, 1,4-cineole and methanethiol. This article is protected by copyright. All rights reserved.

Investigation of In Vitro Apocarotenoid Expression in Perianth of Saffron (Crocus sativus L.) Under Different Soil EC

Crocus sativus is a triploid sterile plant with red stigmas belonging to family of Iridaceae, and sub family Crocoideae. Crocin, picrocrocin, and safranal are three major carotenoid derivatives that are responsible for color, taste and specific aroma of Crocus. Saffron flowers are harvested manually and used as spice, dye or medicinal applications. The natural propagation rate of most geophytes including saffron is relatively low. An in vitro multiplication technique like micropropagation has been used for the propagation of saffron. To understand the efficiency of this alternative and study the molecular basis of apocarotenoid biosynthesis/accumulation, the RT-PCR method was performed on perianth explants that were cultured on MS medium to observe the level of expression of zeaxanthin cleavage dioxygenase (CsZCD) gene during stigma development, and also the impact of soil EC on its expression. The present study was conducted at Plant molecular and physiology Lab, Alzahra University, Tehran, Iran during 2011-2013. Stigma-like structures (SLSs) on calli were collected from immature perianth explants from floral buds of corms that were collected from Ghaen city, and compared to (Torbat-e Haidariye, Mardabad and Shahroud cities) for investigating the impact of different soil EC on CsZCD expression. The results indicated that CsZCD gene was highly expressed in fully developed red SLSs in perianth of cultured samples of Shahroud with the highest salinity. In this research, a close relationship between soil EC and second metabolites regulation is studied. Overall, these results will pave the way for understanding the molecular basis of apocarotenoid biosynthesis and other aspects of stigma development in C. sativus.

The Effect of Monosodium Glutamate Ingestion on Spatial Memory and Cognitive Behaviour in Wistar Rats

Monosodium glutamate (MSG), one of the most widely used food-additives in commercial foods gives a special aroma (umami) to processed foods. It’s vital to brain metabolism and function. Adverse effects of MSG have been widely reported. However, there is scarcity of literature on the action of MSG on spatial memory and cognition. Hence, there is need to assess the effect of MSG ingestion on spatial memory and cognitive behavior in Wistar rats. 25 Wistar rats were randomly selected into five groups and treated for three weeks thus: Group 1 (control), Group 2 (0.7 mL MSG), Group 3 (1 mL MSG), Group 4 (1.5 mL MSG) Group 5 (0.1 mL Epinephrine). Neurobehavioral (Barnes, navigation, and handgrip) activities exhibited by the various groups were recorded and analyzed using ANOVA. In the Barnes maze test, there was a significant decrease (p<0.05) in escape time in group 4 when compared to the control for weeks 1 and 3. In week 1 of the Navigation maze test, group 4 animals spent less time (p<0.05) to navigate the maze when compared to the control. In week 1 and 3 of the handgrip test, animals in groups 2, 3 and 5 had a significant decline (p<0.05) in grip strength when compared to the control group; However, in week 2, only the animals in group 5 had a decline in grip strength (p<0.05) when compared to control. MSG did not cause any form of neurotoxicity, cognitive or motor decline in rats.

Analysis of the Formation of Characteristic Aroma Compounds by Amino Acid Metabolic Pathways during Fermentation with Saccharomyces cerevisiae.

Amino acid metabolic pathways can have profound impacts on the activities of key enzymes in the biosynthesis of specific aroma compounds during yeast fermentation. Aroma compounds, pyruvic acid and glucose were monitored in relation to the key enzymes of leucine aminotransferase (LTR), phenylalanine aminotransferase (PAL), pyruvate kinase (PK) and acetyl-CoA in the amino acid metabolic pathways during the fermentation of simulated juice systems with added amino acids in order to explore the formation of characteristic aroma compounds. The addition of L-phenylalanine or L-leucine to the simulated juice systems significantly improved the activities of PK, PAL and LTR, and the content of acetyl-CoA, and significantly increased the concentrations of phenylethyl alcohol, octanoic acid, isoamyl acetate, phenylethyl acetate, ethyl hexanoate and ethyl caprylate during fermentation. Correlation analysis showed that there was a significant positive correlation between PAL, LTR, PK and acetyl-CoA and pyruvic acid formation. Path analysis revealed that the addition of amino acids affected the metabolism of pyruvate to alcohols, acids and esters to some extent.

Study on the Effects of Processes on Aroma Compounds in Rizhao Green Tea Based on the Gas Chromatography-Ion Mobility Spectrometry

Tea processing plays an important role in the formation of tea aroma. In order to explore the composition and variation in aroma during Rizhao green tea processing, gas chromatography-ion mobility spectrometry was employed to investigate the formation and changes of tea aroma in four processing stages. A total of 62 volatile compounds were identified, including alcohols, aldehydes, ketones, esters, terpenes, and oxygen compounds. Relative odor activity value was used to identify 17 characteristic aroma compounds. The main aromatic compounds of chestnut-like aroma were linalool, pentanal, hexanal, heptanal, octanal, nonanal, 2-methylbutanal, 3-methylbutanal, 3-methylthiopropanal, and methyl 2-methylbutanoate. There were significant changes in the volatile components at different processing stages. Samples of tea leaves and green tea had special aroma characteristics, while samples of fixated and rolled leaves had similar aroma compounds. The results are beneficial for the improvement of the flavor and quality of Rizhao green tea. Practical Application. Tea is the world’s most consumed nonalcoholic beverage, with a multitude of health-promoting benefits, such as antioxidant, antiobesity, and antiallergic activities. At present, the research on the aroma compounds of Rizhao green tea mainly focuses on the aroma characteristics of finished tea and the aroma differences of different kinds of commercial tea. This study explored the effects of the processes on aroma compounds, and the results provide a theoretical reference for the improvement of tea processing technology, tea quality control, and evaluation methods.

Burn Defect and Phenol Prediction for Flavoured Californian-Style Black Olives Using Digital Sensors

Californian-style black olives can undergo different chemical changes during the sterilization process that can affect their sensory and phenol characteristics. Thus, these olives were stuffed with flavoured hydrocolloids and submitted to different thermal sterilization treatments to assess sensory categories. The triangular test indicated that the panellists were able to discriminate between samples from different categories according to their aromas with more than 85% success. The results indicated that the negative aroma detected by tasters was related to burn defects. The highest level of defects was found in standard olives, while the lowest was identified in the extra category. Furthermore, olives submitted to the lowest thermal sterilization treatment (extra) presented significantly higher phenol profile content, such as for hydroxytyrosol, tyrosol, oleuropein and procyanidin B1. The electronic nose (E-nose) discriminated between samples from different categories according to the specific aroma (PC1 = 82.1% and PC2 = 15.1%). The PLS-DA classified the samples with 90.9% accuracy. Furthermore, the volatile organic compounds responsible for this discrimination were creosol, copaene, benzaldehyde and diallyl disulphide. Finally, the models established by the PLS analysis indicated that the E-nose could predict olives according to their aroma and total phenol profile (RCV2 values were 0.89 and 0.92, respectively). Thus, this device could be used at the industrial level to discriminate between olives with different sensory aromas to determine those with the highest quality.

L-Serine is the Direct Precursor for the Pyrazine Ring Construction in the Biosynthesis of 3-Isobutyl-2-Methoxypyrazine in Bell Pepper Fruits (Capsicum annuum L.).

3-Isobutyl-2-methoxypyrazine (IBMP) is an extremely potent odorant and responsible for the specific aroma of many fruits and vegetables. Especially bell pepper contains high levels of IBMP, which is the character impact compound of its typical aroma. However, since the discovery of methoxypyrazines in plants in the 1960s the biosynthesis of their pyrazine ring motif remained so far unknown. Therefore, the biosynthetic pathway to IBMP was investigated by feeding experiments with stable-isotope labeled precursors. For the first time it could be shown that l-serine plays a key role in the pyrazine ring construction of 3-alkyl-2-methoxypyrazines (MPs). Based on HS-SPME-GCxGC-TOF-MS analysis, it is shown that the biosynthetic pathway to IBMP is closely linked to photorespiratory derived l-serine.

Effects of Combined Pure Cultures of Rhizopus sp. (Rhizopus oryzae, Rhizopus oligosporus, and Rhizopus stolonifer) on Tempeh Extract Yogurt as a Functional Food

Background: Tempeh Extract Yogurt was an alternative to tempeh product development that can be used as a functional product. This study aimed to determine the functional food potential of yogurt with tempeh extract by including tempeh using mixed cultures. Methods: The ratio of making tempeh Rhizopus oryzae, Rhizopus oligosporus, Rhizopus stolonifer inoculum of 1:1:1, 1:2:1, 2:1:2, 1:1:2, 2:1:1, respectively; RAPRIMA tempeh starter as a control group was fermented with Lactic Acid Bacteria to produce tempeh extract yogurt. Results: Tempeh extract yogurt by SNI 2891:2009 with the characteristic’s thick liquid, specific aroma, sour taste, and homogeneous consistency. The highest form of vitamin B12 and folate in Tempeh Extract Yogurt was on a 1:2:1 ratio (0.072 g/100 mL and 0.059 g/100 mL), and the genistein isoflavone in RAPRIMA was 3.669 g/100 mL with a pH value of 4.2 and a total bacterium of 14,3 x 108 CFU/mL. Conclusion: Tempeh extract yogurt contains several vitamin B12, folate, isoflavones, and total bacteria Tempeh Extract Yogurt be responsible as a functional food.

Non-targeted metabolomics analyze dough fermented by S. cerevisiae and L. plantarum to reveal the formation of flavor substances of bread

Bread made from dough fermented by Saccharomyces cerevisiae (S. cerevisiae) and Lactobacillus plantarum (L. plantarum) has better quality. The accumulation curve of S. cerevisiae and L. plantarum in dough was measured during the fermentation. The non-targeted metabolomics was used to learn the metabolites in dough fermentation by S. cerevisiae and L. plantarum for 3 h. A total of 604 metabolites were identified for the positive mode. Compared with dough fermented by S. cerevisiae, 139 differential metabolites were detected in dough fermented by S. cerevisiae and L. plantarum, in which 83 and 56 metabolites were significantly up-regulated and down-regulated, respectively. The content of amines, pyrazine substances, amide, amino acids, acetamide and other substances having special aroma to improve the quality of bread increased and accumulated, and the content of indole with unpleasant taste decreased and consumed in the metabolic process in the dough samples fermentation by S. cerevisiae and L. plantarum. Tryptophan metabolism was the most enriched metabolic pathway of differential metabolites through the KEGG database enrichment. This indicated that S. cerevisiae and L. plantarum fermented dough was closely associated with the taste quality, the generation of flavor substances of bread and tryptophan metabolism.

Investigating the Aromatic Compound Changes in Table Grape Varieties during Growth and Development, Using HS-SPME-GC/MS

This study aimed to identify the aromatic compounds present in the different aroma types of different table grape varieties and deeply understand the changes in the aromatic compounds during the growth and development process. The skin and flesh of three table grape varieties (‘Kyoho’, ‘Shine Muscat’, and ‘Ryuho’) in different growth and development stages were selected to determine their aromatic compounds using headspace solid-phase microextraction gas chromatography-mass spectrometry and principal component analysis. The results showed that the aromatic compounds of the ‘Kyoho’ and ‘Ryuho’ grapes were similar, mainly containing C6 compounds and esters, whereas ‘Shine Muscat’ was characterized by C6 compounds and terpenes. The levels of aromatic compounds in the skin were higher than those in the flesh. The content of esters in ‘Ryuho’ was significantly higher than that in ‘Kyoho’ and ‘Shine Muscat’. This showed that ‘Ryuho’ combines the advantages of the parents in its aroma composition. Selecting suitable parents for hybridization is one method for obtaining new varieties with a special aroma. This provides a theoretical basis for future molecular hybrid breeding and molecular-assisted breeding, as well as molecular biology research on aroma synthesis and metabolism in table grapes.

Integrated transcriptomic and volatilomic profiles to explore the potential mechanism of aroma formation in Toona sinensis

As an important quality determinant of Toona sinensis, the unique aroma largely impacts the purchasing behavior of consumers. However, the underlying formation mechanism of the characteristic aroma of T. sinensis remains poorly understood. In this work, integrative volatile/nonvolatile compounds profiling and RNA sequencing were used to characterize six T. sinensis cultivars. Volatile sulfur compounds (VSCs) and terpenoids were the main volatile organic compounds (VOCs) in T. sinensis, accounting for 36.95–67.27% and 17.75–31.36% of the total VOC content, respectively. Notably, the VOCs originated from terpenoid biosynthesis, and the degradation of unsaturated fatty acids (UFAs) played important roles in reconciling the irritating odor of VSCs. The above differential metabolic profiles are the main sources of the specific aroma of different T. sinensis cultivars. Furthermore, 13 volatile organic compounds were identified as potential biomarkers to distinguish these T. sinensis cultivars by chemometric analysis. Based on the analysis of transcriptomic datasets, the potential biosynthetic pathways of the key VSCs were firstly confirmed in T. sinensis. It was found that 1-propenylsulfenic acid is a crucial precursor in the formation of characteristic VSCs in T. sinensis. Additionally, two potential mechanisms were proposed to explain the differences of the key VSCs among six T. sinensis cultivars. These results provide theoretical guidance for improving the aroma quality of T. sinensis.

Variations in heterochromatin content reveal important polymorphisms for studies of genetic improvement in garlic (Allium sativum L.).

Allium sativum L. is an herb of the Alliaceae family with a specific taste and aroma and medicinal and nutraceutical properties that are widely marketed in several countries. Brazil is one of the largest importers of garlic in the world, despite of its production is restricted and limited to internal consumption. Thus, explore the genetic diversity of commercial garlic conserved at germplasm banks is essential to generate additional genetic information about its economically important crop. A suitable tool for this purpose is the cytogenetic characterisation of these accessions. This study aimed to characterise the cytogenetic diversity among seven accessions of garlic from a Germplasm Bank in Brazil. The karyotypes were obtained by conventional staining and with chromomycin A3 (CMA) and 4,6-diamidino-2-phenylindole (DAPI) fluorochromes. All accessions analysed showed chromosome number 2n = 16, karyotype formula 6M+2SM, symmetrical karyotypes, reticulate interphase nuclei, and chromosomes with uniform chromatin condensation from prophase to metaphase. The fluorochromes staining showed differences in the amount and distribution of heterochromatin along the chromosomes and between accessions studied. Based on the distribution pattern of these small polymorphisms, it was possible to separate the seven accessions into three groups. It was also possible to differentiate some of the accessions individually. One of the results obtained showed a heteromorphic distension of the nucleolar organiser region observed on the chromosome pairs 6 or 7 with peculiar characteristics. It was suggested for example, that the heteromorphic block of heterochromatin (CMA+++/DAPI-) on chromosome 6 of the "Branco Mineiro Piauí" accession can be used as a marker to identify this genotype or may be associated with some character of economic interest.

1-Amino-1-deoxy-d-fructose ("fructosamine") and its derivatives.

Fructosamine has long been considered as a key intermediate of the Maillard reaction, which to a large extent is responsible for specific aroma, taste, and color formation in thermally processed or dehydrated foods. Since the 1980s, however, as a product of the Amadori rearrangement reaction between glucose and biologically significant amines such as proteins, fructosamine has experienced a boom in biomedical research, mainly due to its relevance to pathologies in diabetes and aging. In this chapter, we assess the scope of the knowledge on and applications of fructosamine-related molecules in chemistry, food, and health sciences, as reflected mostly in publications within the past decade. Methods of fructosamine synthesis and analysis, its chemical, and biological properties, and degradation reactions, together with fructosamine-modifying and -recognizing proteins are surveyed.

Evaluation of volatile flavor compounds in rice with different degrees of roasting based on GC-IMS and PCA analysis

The differences of volatile odorants of rice at different roasting levels were analyzed by headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) using fingerprints combined with principal component analysis (PCA). GC-IMS and PCA could distinguish the different roasting levels of rice and the results showed that a total of 47 representative flavor compounds were detected in four samples from all roasting stages. The aroma components of roasted rice are mainly aldehydes and ketones, furans and pyrroles, as well as a large number of phenols, esters and alcohols, which make up the special aroma flavor of roasted rice. It can be seen that the flavor characteristics of roasted rice can be reflected more fully when the rice is roasted in medium (18 min), and can have more fruit wood, cream and roasted aromas. The PCA based on the signal intensity of the detected volatile compounds revealed effective differentiation of samples from different stages into comparatively independent spaces. Thus, the differences of volatile compounds from different roasting stages of rice were determined, and the flavor fingerprints of that can be successfully established using HS-GC-IMS and PCA.

Exploiting the Native Microorganisms from Different Food Matrices to Formulate Starter Cultures for Sourdough Bread Production.

The use of sourdough for bread production involves fermentation, which is dominated by lactic acid bacteria (LAB) and yeast. Sourdough can be inoculated with a starter culture or through a food matrix containing microorganisms to initiate sourdough fermentation. Sourdough is used as leavening agent for bread making, and metabolites produced by LAB and yeast confer a specific aroma and flavor profile to bread, thus improving its sensory attributes. However, few publications report the effect of microorganisms from different food products and by-products on sourdough fermentation. This review focuses on using different starter cultures from various food sources, from wheat flour to starter cultures. Additionally, included are the types of sourdough, the sourdough fermentation process, and the biochemical transformations that take place during the sourdough fermentation process.

Insights into the Key Odorants in Large-Leaf Yellow Tea (Camellia sinensis) by Application of the Sensomics Approach

Large-leaf yellow tea (LYT) is a yellow tea product with a specific aroma characteristic and is enjoyed with increasing enthusiasm in China. However, its key odorants are still unknown. In this study, 46 odorants in the headspace and vacuum-distillate of the tea infusion were identified via aroma extract dilution analysis. Sixteen compounds were newly found in LYT infusion. They were present in the highest flavor dilution factors together with 2-ethyl-3,5-dimethylpyrazine. All odorants were quantitated to evaluate their own odor activity values (OAVs). High OAVs were found for 2-methylbutanal (malty, 210), (E,E)-2,4-heptandienal (fatty/flowery, 170), 2-methylpropanal (malty, 120) and 2,3-diethyl-5-methylpyrazine (earthy/roasty, 110). An aroma recombinate consisting of 17 odorants (all OAVs ≥ 1) in an odorless nonvolatile LYT matrix mimicked the overall aroma of the original infusion, verifying the successful characterization of key aroma components in a LYT beverage. The knowledge of key odorants obtained showed potential for simplifying industrial flavor optimization of the LYT product.

Synthesis of Aroma Compounds as a Function of Different Nitrogen Sources in Fermentations Using Non-Saccharomyces Wine Yeasts.

Non-Saccharomyces yeasts are prevalent at the onset of grape must fermentations and can have a significant influence on the final wine product. In contrast to Saccharomyces cerevisiae, the biosynthetic pathways leading to aroma compound formation in these non-conventional yeasts, in particular those that are derived from amino acid metabolism, remains largely unexplored. Within a synthetic must environment, we investigated the amino acid utilization of four species (Hanseniaspora uvarum, Hanseniaspora osmophila, Zygosaccharomyces rouxii, Starmerella bacillaris) and S. cerevisiae. We report on the differential uptake preferences for amino acids with H. uvarum displaying the most rapid uptake of most amino acids. To investigate the fate of amino acids and their direct contribution to aroma synthesis in H. uvarum, H. osmophila and Z. rouxii, musts were supplemented with single amino acids. Aroma profiling undertaken after three days showed the synthesis of specific aroma compounds by the respective yeast was dependent on the specific amino acid supplementation. H. osmophila showed similarities to S. cerevisiae in both amino acid uptake and the synthesis of aroma compounds depending on the nitrogen sources. This study shows how the uptake of specific amino acids contributes to the synthesis of aroma compounds in wine fermentations using different non-Saccharomyces yeasts.

Identification of ligustrazine-based analogs of piperlongumine as potential anti-ischemic stroke agents

Piper longum has a specific aroma and spicy taste. In addition to edible value, current studies have shown that piper longum also has pharmacological activities such as anti-platelet aggregation, anti-inflammation, anti-cancer, anti-diabetes and anti-depression. Piperlongumine is an alkaloid isolated from Piper longum. Based on our previous studies, four Piperlongumine analogs were synthesized, and their anti-platelet aggregation activities were evaluated. Among them, compound 8 has the strongest anti-platelet aggregation activity. Therefore, compound 8 was docked with stroke-related protein targets, and it was found that compound 8 had good binding affinity to MRTF-A complex and Bcl-2. Through animal experiments, it was found that compound 8 could significantly improve the pathological damage of brain tissue after ischemia and could increase the expression of MRTF-A and Bcl-2 in cerebral cortex in rats. These results suggest that compound 8 may have a good inhibitory effect on apoptosis and tissue structurel disorders induced by cerebral ischemia-reperfusion, so as to reduce the injury caused by ischemic stroke.

Adaptation of expert wine assessors to less familiar sensory testing methods without pretraining

Wine sensory testing is carried out by assessors who are usually selected and prepared depending on the test type, and their skills may vary depending on various factors. Expert wine assessors should have superior sensory evaluation abilities, an expert grape and wine knowledge level but even more assessment competence. The aim of this research was to test the competencies of certified Croatian expert wine assessors using a less-familiar descriptive sensory methodology with no preliminary training. These assessors are highly educated in viticulture and/or enology and work in this sector. They have certified sensory skills and shorter or longer experience in sensory testing wines with Geographical indications. Twenty-three assessors participated in the study, and the results were segmented by gender and age. The testing was performed in a laboratory accredited by ISO/IEC 17025. Graševina and Zweigelt wines were tested, and two groups of attributes were analyzed (main quality attributes and specific aroma descriptors). Qualitative and quantitative statistics showed that expert wine assessors had a very similar approach in the choice of descriptors and the perception of their intensity. No difference was obtained in testing any attribute and descriptor, neither for any wine nor between segmented groups concerning age. A significant difference was observed only between women and men in their perception of the two specific aroma descriptors. The results confirmed that combining expert knowledge and experience based on professional education and continuous analytical work can replace a lack of experience in some less-familiar methods.

Sensory properties of 6- and 18-month-stored wines made with pectinase-producing non-Saccharomyces yeasts.

Recently, the use and commercial availability of non-Saccharomyces yeasts (NSY) in winemaking to reduce alcohol content have increased. However, research exploring the influence on sensory quality of the wine, particularly during storage, is limited. Therefore, the objective of this study was to characterize the sensory profiles of Merlot and Chardonnay wines made with pectinase-producing NSY, with added substrate, that is, pectin. Apple pectin (0 or 0.5g/L) was added to Merlot and Chardonnay grape musts after inoculation with (a) only Saccharomyces cerevisiae or (b) a three species mixture of NSY; after 3days, S. cerevisiae was added. Addition of NSY with added pectin resulted in higher concentrations of d-galacturonic acid and glycerol concentration in the wines after 6months of aging. However, mouthfeel (viscosity or weight) of wines with or without added pectin as determined by a sensory evaluation panel was not altered by the presence of these yeasts. Significant interactions among the yeast utilized, pectin addition, and 6-month aging affected some flavors (solvent) of Merlot, while addition of NSY increased other attributes (cherry) during aging. No sensory differences were perceived among Chardonnay samples due to NSY; however, aging from 6 to 18 months increased the intensity of 40 sensory attributes. Though mouthfeel was not specifically affected, the utilization of NSY may be a useful tool to alter wine quality in Merlot by increasing specific aromas during storage. PRACTICAL APPLICATION: We found that must fermented with pectinase-producing non-Saccharomyces yeasts (NSY) modified the chemical composition of the final young wine. After one additional year of aging, an increase in cherry flavor was observed in Merlot wines made with NSY, which may increase perceived quality. Thus, the use of these pectinase-producing NSY may be a useful tool for winemakers.