High Levels Of Terpenes Research Articles

Effect of different inoculation strategies of mixed culture Saccharomyces cerevisiae/Oenococcus oeni on the aroma quality of Chardonnay wine

There has been growing interest in the use of mixed cultures comprised of Oenococcus oeni and Saccharomyces cerevisiae to produce wine with local style and typicality. This study has investigated the influence of the inoculation protocol of O. oeni on the fermentation kinetics and aromatic profile of Chardonnay wine. The one selected autochthonous O. oeni strain (ZX-1) inoculated at different stages of the alcoholic fermentation process successfully completed malolactic fermentation (MLF). Co-inoculum of S. cerevisiae and O. oeni enabled simultaneous alcoholic fermentation and MLF, leading to at least a 30 % reduction in the total fermentation time when compared to the sequential inoculation process, which was attributed to the lower ethanol stress. Meanwhile, co-inoculum stimulated the accumulation of volatile aroma compounds in Chardonnay wine. In particular, the mixed modality where the O. oeni strain ZX-1 was inoculated 48 h after S. cerevisiae allowed higher levels of terpenes, acetates, short-chain, and medium-chain fatty acid ethyl esters to be produced, which may result in the enhanced floral and fruity attributes of wine. Aroma reconstitution and omission models analysis revealed that the accumulation of linalool, geraniol, isoamyl acetate, ethyl hexanoate, and ethyl caprylate during the mixed fermentation process enhanced the stone fruit, tropical fruit, and citrus aromas in Chardonnay wine. Therefore, the simultaneous fermentation of S. cerevisiae and autochthonous O. oeni ZX-1 has a positive effect on MLF and contributes to producing wines with distinctive style.

Combining with volatilomic profiling and chemometrics to explore the volatile characteristics in five different dried Zanthoxylum bungeanum maxim

Owing to the short picking period of the fresh Zanthoxylum bungeanum, the postharvest drying has become an essential operation before the storage and transportation of Z. bungeanum. To explore the effects of drying methods on volatile characteristics, the volatilomic profiling of five different dried Z. bungeanum was investigated by E-nose, HS-SPME-GC/MS, GC-IMS in combination with chemometrics. The results indicated that W1W, W2W and W5S sensors within E-nose analysis showed the strongest responses in both fresh and dried Z. bungeanum. According to the identification of volatile organic compounds (VOCs), terpenes, esters and alcohols played the major roles in the volatile formation of the fresh and dried Z. bungeanum. The samples derived from hot air drying showed the relatively similar features with the fresh sample based on the relative abundances of these major VOCs. According to the results of multiple factor analysis (MFA), GC-IMS showed the strongest ability in distinguishing the fresh and different dried samples. Compared with the high levels of terpenes in fresh group, the significant increasement of terpene alcohols and terpene esters from the degradation and transformation of bound terpenoids was the main characteristics of all dried Z. bungeanum. Using the GC-IMS datasets, a weighted correlation network analysis (WCNA) model was constructed to clarify the VOC characteristics in all detetected samples. Thereinto, 6 significantly correlated modules were identified in fresh and five different dried samples. Additionally, a total of 23 hub VOCs can be recognized as the potential biomarkers for better distinguishing the fresh and five different dried Z. bungeanum.

Metabolomic evidence of independent biotransformation pathways for terpenes in two specialist mammalian herbivores (genus Neotoma).

Herbivory is common in mammals, yet our understanding of detoxification processes used by mammals to biotransform plant secondary compounds (PSCs) is limited. Specialist herbivores are thought to have evolved detoxification mechanisms that rely more heavily on energetically cheap Phase I biotransformation reactions to process high levels of PSCs in their diets. We explored this hypothesis by comparing the urinary metabolite patterns of two specialist herbivores (genus Neotoma). Neotoma stephensi is an obligate specialist on one-seeded juniper (Juniperus monosperma). Neotoma lepida is a generalist forager across its range, yet populations in the Great Basin specialize on Utah juniper (J. osteosperma). While both juniper species have high levels of terpenes, the terpene profiles and quantities differ between the two. Individuals from both woodrat species were fed diets of each juniper in a cross-over design. Urine, collected over a 24-h period, was extracted and analyzed in an untargeted metabolomics approach using both GC-MS and HPLC-MS/MS. The obligate specialist N. stephensi excreted a unique pattern of Phase I metabolites when fed its native juniper, while N. lepida excreted a unique pattern of Phase II metabolites when fed its native juniper. Both woodrat species utilized the Phase II metabolic pathway of glucuronidation more heavily when consuming the more chemically diverse J. osteosperma, and N. stephensi utilized less glucuronidation than N. lepida when consuming J. monosperma. These results are consistent with the hypothesis that obligate specialists may have evolved unique and efficient biotransformation mechanisms for dealing with PSCs in their diet.

Exploring the Potential of the Model Cyanobacteria Synechococcus PCC 7002 and PCC 7942 for the Photoproduction of High-Value Terpenes: A Comparison with Synechocystis PCC 6803.

We have performed the first comparative analysis of the potential of two physiologically-diverse model cyanobacteria, Synechococcus PCC 7002 (S.7002) and Synechococcus elongatus PCC 7942 (S.7942), for the photosynthetic production of four chemically-different high-value terpenes: two monoterpenes limonene and pinene, and two sesquiterpenes bisabolene and farnesene. We showed, for the first time, that S.7002 and S.7942 can produce farnesene and bisabolene, respectively. Both cyanobacteria produced farnesene (S.7942 produced more efficiently than S.7002) more efficiently than the other tested terpenes (especially pinene, the weakest produced terpene). S.7002 produced limonene more efficiently than bisabolene, whereas S.7942 produced bisabolene more efficiently than limonene. These findings suggest that S.7942 is better suited to produce sesquiterpenes than monoterpenes. Interestingly, higher levels of terpenes were produced by S.7942 and S.7002 expressing a terpene-synthase gene from both an RSF1010-derived replicating plasmid and a neutral chromosomal site, as compared to either the plasmid alone or the chromosome alone. These results suggest that in both cyanobacteria, the production of terpenes is more limited by the activity of terpene synthases than the abundance of terpene precursors. Finally, higher levels of terpenes were produced by S.7002 growing on urea (a frequent pollutant) as compared to nitrate or ammonium, the standard nitrogen sources for cyanobacteria.

Corinthian currants finishing side-stream: Chemical characterization, volatilome, and valorisation through wine and baker’s yeast production-technoeconomic evaluation

The industrial currants finishing generates a considerable amount of side-stream (FSS) with great potential for biotechnological exploitation. The chemical composition of FSS generated from the premium quality Vostitsa currants was studied. Its use for wine making (at low temperatures, using both free and immobilized yeast) combined with baker’s yeast production (with minor nutrient supplementation), is also proposed. Analysis showed that FSS has a rich volatilome (including Maillard reaction/lipid degradation products), increased antioxidant capacity, and total lipid and phenolic contents, compared to the marketable product (currants). However, acidity levels and the presence of specific volatiles (such as acetate esters and higher alcohols) may be indicative of microbial spoilage. The wines made from FSS were methanol free and contained higher levels of terpenes (indicating hydrolysis of bound forms) and fermentation-derived volatiles, compared to FSS. A preliminary technoeconomic analysis for integrated wine/baker’s yeast industrial production, showed that the investment is realistic and worthwhile.

Anthelmintic Activity of Yeast Particle-Encapsulated Terpenes.

Soil-transmitted nematodes (STN) infect 1–2 billion of the poorest people worldwide. Only benzimidazoles are currently used in mass drug administration, with many instances of reduced activity. Terpenes are a class of compounds with anthelmintic activity. Thymol, a natural monoterpene phenol, was used to help eradicate hookworms in the U.S. South circa 1910. However, the use of terpenes as anthelmintics was discontinued because of adverse side effects associated with high doses and premature stomach absorption. Furthermore, the dose–response activity of specific terpenes against STNs has been understudied. Here we used hollow, porous yeast particles (YPs) to efficiently encapsulate (>95%) high levels of terpenes (52% w/w) and evaluated their anthelmintic activity on hookworms (Ancylostoma ceylanicum), a rodent parasite (Nippostrongylus brasiliensis), and whipworm (Trichuris muris). We identified YP–terpenes that were effective against all three parasites. Further, YP–terpenes overcame albendazole-resistant Caenorhabditis elegans. These results demonstrate that terpenes are broad-acting anthelmintics. Terpenes are predicted to be extremely difficult for parasites to resist, and YP encapsulation provides water-suspendable terpene materials without surfactants and sustained terpene release that could lead to the development of formulations for oral delivery that overcome fast absorption in the stomach, thus reducing dosage and toxic side effects.

Impact of various maceration techniques on the phenolic and volatile composition of Chenin Blanc wines

SummaryChenin Blanc, cultivated in cool climate regions, was chosen to evaluate the impact of different maceration techniques on polyphenolic profiles and volatile compounds. Control with no skin contact (CK), cold maceration (CM), cryogenic maceration (CR), separate fermentation before blending (SFB) and extended skin contact during fermentation (ESF) were the five maceration techniques being studied. SFB and ESF techniques resulted in significantly increased polyphenolic compounds compared to the control (P < 0.05), while CM and CR maceration techniques resulted in almost no effect. Meanwhile, for aromatic components, the maximum change was observed in ESF wine, which had significantly highest levels of terpenes, alcohols, esters and acids. However, compared with control wine, CR wine had higher levels of terpenes and esters and SFB wine had higher levels of terpenes and alcohols. This study provides information about prefermentation techniques and additional options for oenologists to produce Chenin Blanc wines with different characteristics.

Comparison of the aromatic profile of three aromatic varieties of Peruvian pisco (Albilla, Muscat and Torontel) by chemical analysis and gas chromatography–olfactometry

ABSTRACTForty‐five samples of commercial pisco made with Albilla, Muscat and Torontel grapes in different areas of Peru have been evaluated by gas chromatography–olfactometry (GC‐O) and chemical quantitative analysis. The GC‐O study revealed that the Peruvian pisco made of these varieties of grapes has an aroma profile formed by nearly 30 odorants. The odorant 2,3‐pentanedione was detected only in the Albilla sample, producing significant differences. The chemical analysis of the volatiles of these samples showed volatile profiles quite typical of a wine distillate. The Torontel samples (considered the most aromatic variety) were marked by high levels of terpenes and β‐damascenone, the Albilla samples showed the lowest values of terpenes, which may explain their low scores obtained during the sensory analysis, while the Muscat samples showed intermediate levels of this family of compounds and were characterized by high concentrations of benzyl alcohol and β‐phenylethanol. Furthermore, an evaluation of the sensory contribution of terpenes in these piscos was carried out, demonstrating that linalool is the most odour‐active terpene, exceeding its odour threshold in 34 out of 45 piscos analysed. However, the other terpenes should also be considered as important contributors to the aroma of piscos because a certain degree of cooperation between the components of this family has been demonstrated. The quantitative analysis data allowed us to distinguish pisco samples according to their variety and could explain some sensory differences observed depending on the nature of the grapes. Copyright © 2013 John Wiley & Sons, Ltd.

Comparative Analysis of the Aroma Compounds of Muscat Hamburg Dry White Wines from Different Wine Regions in China

The aroma compoumds of Muscat Hamburg dry white wines from three different wine regions, made with the same brewing technology, were determined by head space solid phase microextraction coupled with gas chromatography mass spectrometry (HS-SPME-GC/MS), with grapes harvested in 2010 from Tianjin Hangu, Heibei Changli and Shandong Pingdu regions as raw materials. Total 58 volatile compounds were identified and 23 componds were quantified. The results show that the wines from Hangu regions contained relatively high levels of terpenes and esters, and lower contents of higher alcohols,which contributed to the wines rich floral and fruity aromas and sweet, musky flavors.

CHANGES IN VOLATILE PRODUCTION AND SENSORY QUALITY OF ACTINIDIA ARGUTA FRUIT DURING FRUIT MATURATION

Fruit of Actinidia arguta ('Hortgem Tahi', 'Hortgem Rua', 'Hortgem Toru' and 'Hortgem Wha') were evaluated at different softening stages during ripening. The volatiles released from the fruit and their sensory qualities, as assessed by a trained taste panel, were compared with those of A. deliciosa 'Hayward' and A. chinensis 'Hort16A' fruit. Gas chromatography-mass spectrometry (GC-MS) data indicated that each species had different characteristic volatiles. Straight chain aldehydes and esters were the dominant volatiles detected during the ripening of A. arguta fruit. As in 'Hayward' fruit, the total percentages of (E)-2-hexenal and hexanal, which impart green characteristics, decreased as the fruit softened. Butanoates (fruity characteristics) detected in the fruit increased as fruit firmness decreased. However, in the A. arguta fruit, higher levels of terpenes and aldehydes were detected. With fruit softening, sensory perception of acidity decreased but typical kiwifruit odour and flavour intensity (ethyl butanoate) increased. More tropical aroma and a slightly bitter skin taste were also noted by panellists for all tested fruit.

Sensory properties and aroma compounds of sweet Fiano wine

The aroma of sweet Fiano wine, the most representative non-aromatic white wine variety in southern Italy, was evaluated by sensory and instrumental analysis to determine the influence of grape overripeness, drying and Botrytis cinerea infection. Sensory descriptive analysis was used to evaluate the sensory properties of wines. Gas chromatography/mass spectrometry (GC/MS), gas chromatography (GC) and gas chromatography/olfactometry (GC/O) techniques were used to identify and to determine the content of free and bound volatile compounds and their odour impact. A sensory descriptive analysis had revealed that the sensory descriptors such as citrus jam, dried apricot, dried figs, prune, honey and coconut, occur in sweet Fiano wine more than in base Fiano wine. Thirty five free volatile compounds had higher levels in sweet Fiano wine than in base Fiano wine, these components were mostly terpenes, β-damascenone, lactones, aldehydes and ketones. Moreover higher levels of terpenes, β-damascenone, benzyl alcohol and 2-phenylethanol were found in the bound volatile fraction of sweet Fiano wine. The main odour impact compounds in sweet Fiano wine were nerol, geraniol and linalool (orange flowers), vitispirane (camphor), lactones such as γ-nonalactone (coconut), δ-decalactone and γ-decalactone (apricot) and 1-octen-3-ol (mushroom). These differences appear to be due to the fact that grape overripeness and the drying process allows concentration of varietal aromatic compounds and an easier transfer of them from skins to must during vinification.

Influence of stock density and rate and temporal patterns of forage allocation on the diet mixing behavior of sheep grazing sagebrush steppe

An animal's ability to select a diet depends on forage availability, the density of herbivores, and the allocation of forage resources. We hypothesized that the temporal and spatial availability of forages in sagebrush steppe vegetation both influence food selection and may encourage lambs to learn to use sagebrush, a shrub that contains high levels of terpenes that limit food intake. We conducted a field study with three treatments of 20 lambs each. Forage resources were manipulated by restricting grazing areas. Lambs in treatment H grazed at a high stock density, whereas lambs in treatment L grazed at a low stock density; both groups were moved to fresh pasture daily. Lambs in treatment H3 had three times the area of treatment H, but they were moved every 3 days, making the total area grazed by H and H3 equal, but with a different temporal allocation of forage. Scan sampling was used to record the incidence of consumption among sagebrush and understory herbs. During 24 days of conditioning, stock density and temporal patterns of forage allocation both influenced the behavior of lambs. Lambs in H spent more time foraging on sagebrush (25%) than lambs in H3 (16%), and lambs in both H and H3 spent more time foraging on sagebrush than lambs in L (1%) ( P < 0.05). For lambs in H3, foraging on sagebrush was cyclic and depended on the daily availability of herbs. Use of sagebrush, expressed as a percentage of total foraging time, was <1% for day 1, 13% for day 2, and 37% for day 3 ( P < 0.0001). Importantly, use of sagebrush by H3 and H increased steadily as the trial progressed, whereas use of sagebrush by L was consistently low ( P < 0.05). Following conditioning, when lambs were tested at low stock densities during preference test 1, use of sagebrush did not differ by groups, but at higher stock densities in preference test 2, their use of sagebrush varied by treatments: H > H3 > L ( P < 0.005). Thus, the availability of alternative foods, manipulated through animal density and the temporal allocation of those resources, both affected how readily lambs learned to use sagebrush.