Effects of grape variety and roasting on the proanthocyanidin oligomers distribution, cyclic proanthocyanidins, and total polyphenol content in grape seed powders

Grape seeds are a valuable source of natural phenolic compounds, particularly flavan-3-ol derivatives such as condensed tannins. Recent studies have shown that grape seed powder can be applied to reduce the undesirable effects of protein instability in wine. One pretreatment method applied to grape seeds is roasting. Roasting causes the heavier proanthocyanidins (PAC) oligomers to break down, thereby increasing the concentration of smaller oligomers available for interaction with proteins. In addition, roasting can prolong grape seed storage. Among the subclasses of proanthocyanidins, oligomeric macrocyclic proanthocyanidins have also shown potential effects in terms of wine stabilization, particularly by presenting selective interactions with metal cations such as potassium and calcium. However, their composition in grape seed extracts has never been studied. Here, the characterization of condensed tannins according to the degree of polymerization in grape seeds, the profile of cyclic proanthocyanidins and the total polyphenol content were characterized in relation to different grape varieties and the application of roasting. Roasting greatly influenced the distribution of PAC according to the degree of polymerization, increasing the abundance of almost all classes of PAC. However, the overall effect of roasting was highly dependent on grape variety. PAC were analyzed according to the degree of polymerization. Grape seed roasting of red varieties (Croatina and Sangiovese) showed an increase in all classes of PAC except trimers. The white variety (Ortrugo) and the mix of Nebbiolo and Barbera varieties (80% and 20% w/w, respectively) showed no clear effect on the profile of PAC upon roasting. Notably, cyclic procyanidins were identified for the first time in grape seeds: a cyclic tetrameric procyanidin (ESI + m/z 1153) and cyclic pentameric procyanidin (ESI + m/z 1441) were found. The abundances of these cyclic PAC were found to be completely stable upon roasting, also in agreement with the already known stability of these compounds against depolymerizing conditions. Interestingly, the cyclic pentameric procyanidin was significantly more abundant in Ortrugo (white variety), than in Sangiovese and Croatina (red varieties). Besides, no effect of roasting occurred on the profile of cyclic procyanidins in grape seed powder. Finally, the total polyphenol content was evaluated, showing that roasting caused an increase of polyphenolic molecular species potentially available for protein stabilization, but only in GSP of red varieties. Overall, the grape variety was found to be a significant factor in determining how much the roasting would change the PAC profile, providing valuable information for future applications of GSP in enology

Adsorption Capabilities of Fungoid Chitosan Toward Organic Acids in Model Solutions and White Wine

In oenology, fungoid chitosan (CH) can be used as an adjuvant for microbial control, haziness prevention, metal chelation, and ochratoxin removal. In acidic media (such as wine), CH can ionise and interact with charged compounds, giving rise to a series of adsorption and/or removal phenomena, some of which potentially impairing the overall quality of wines. In this context, it is worth noting that the interaction between CH and acidic components of wines has been poorly studied so far, and detailed information on this subject is still lacking. To study those interactions, different doses of chitosan (0.5; 1.0; 2.0 g/L) were dispersed in hydro-alcoholic solution (HS), synthetic wine solution (SW), and white wine (W). Results demonstrated that the remotion of tartaric acid and the change of pH were strongly affected by the matrix and dosage. In W and SW, chitosan was found to adsorb tartaric acid up to about 200 mg/g and 350 mg/g CH, respectively. Accordingly, pH values increased; however, the magnitude depended on the matrix as a consequence of different buffer capacities. Interestingly, even in the absence of tartaric acid (e.g. in HS samples) CH addition caused a pH increase (up to 1.2 units for 2 g/L CH addition) which demonstrated that pH variations may not only depend on the amount of organic acids adsorbed. The chitosan dispersed in W showed the highest average diameter D [3,2] (127.96 μm) compared to the ones dispersed in SW (120.81 μm) and in HS (116.26 μm), probably due to the presence of organic acids on the polymer surface. The minor removal of tartaric acid in W compared to SW could probably depend on the competitive adsorption onto chitosan of other families of compounds present in wine such as polyphenols. The data suggested that chitosan addition could affect the pH and organic acid concentration of all matrices, depending on the doses and composition of the solutions

Physico-chemical and sensory characterization of a fruit beer obtained with the addition of cv. Lambrusco grapes must

In 2015, Italian Grape Ale (IGA) beers have been included as a new provisional sub-category of special-type fruit beers by the Beer Judge Certification Program, including those products whose brewing process is carried out in presence of determined quantities of grape must. However, information on the effects of these additions on the composition of final beers are still scarce. This work is hence focused on the chromatic, volatile, phenolic and sensory characterization of IGA beers obtained with the addition of grape musts during brewing process. To this aim, different amounts of must (5, 10 and 20%) from cv. Lambrusco red grapes were added to a lager wort before primary fermentation. Beers were then characterized by HPLC-MS, GC-MS and sensory analysis in order to determine phenolic and aroma compounds along with their sensory attributes. Results confirmed the addition of must from cv. Lambrusco grapes capable to enrich beers in color, acids, phenolic (up to 7-folded increased) and volatile compounds, while giving complexity to beers. These results, which were confirmed by a trained sensory panel, are among the very first insights on the impact of red grape must in brewing, both from a compositional and sensory point of view

A Room Full of Rocking Chairs: Urban Appalachian Student Experiences in Community College

Urban Appalachian college students (UACS) face cultural and institutional barriers that impact their ability to persist and complete college. Designed to explore UACS experiences at a large urban community college, this study provides insight into Appalachian culture and identity as they impact their success in higher education. UACSs are more likely to come from a low-income family, and be the first in their family to attend college. First-generation college students more often lack the social and cultural capital needed to successfully navigate college, further increasing the risk of failure (Bradbury, 2009). Colleges and universities must seek out ways to improve the campus environment to reflect the needs and values of the students they serve and develop support systems that nurture the development of cultural capital needed to be successful in college and beyond (Oldfield, 2007).https://ecommons.udayton.edu/stander_posters/1382/thumbnail.jp

Physico-chemical and sensory characterization of a fruit beer obtained with the addition of cv. Lambrusco grapes must

In 2015, Italian Grape Ale (IGA) beers have been included as a new provisional sub-category of special-type fruit beers by the Beer Judge Certification Program, including those products whose brewing process is carried out in presence of determined quantities of grape must. However, information on the effects of these additions on the composition of final beers are still scarce. This work is hence focused on the chromatic, volatile, phenolic and sensory characterization of IGA beers obtained with the addition of grape musts during brewing process. To this aim, different amounts of must (5, 10 and 20%) from cv. Lambrusco red grapes were added to a lager wort before primary fermentation. Beers were then characterized by HPLC-MS, GC-MS and sensory analysis in order to determine phenolic and aroma compounds along with their sensory attributes. Results confirmed the addition of must from cv. Lambrusco grapes capable to enrich beers in color, acids, phenolic (up to 7-folded increased) and volatile compounds, while giving complexity to beers. These results, which were confirmed by a trained sensory panel, are among the very first insights on the impact of red grape must in brewing, both from a compositional and sensory point of view

Sensory profile of Italian Espresso brewed Arabica Specialty Coffee under three roasting profiles with chemical and safety insight on roasted beans

Specialty coffee (SC) has been showing an increasing interest from the consumers which appreciate its traceability and the peculiar flavours from each single origin. Additionally, the processes to which coffee fruits underwent to get green coffee characterise the beans in terms of macromolecules acting as substrates during the roasting. This work evaluates via sensory analysed eight SC, roasted at light, medium, and dark level, submitted to Italian espresso extraction, to assess how different roasting levels exalt the expected cup profile obtained by the suppliers via cupping in origin countries. Finally, roasted beans were characterised for physico-chemical features (pH, titratable acidity, caffeine, melanoidins, polyphenols and acrylamide). Sensory analysis demonstrated that the intermediate roasting level and espresso extraction match better attributes from in-origin cupping. Melanoidins (mmol g−1 coffee d.b.) was able to discriminate among roasting levels (light 0.12 ± 0.01; medium 0.13 ± 0.003; dark 0.14 ± 0.01; α = 0.05). Acrylamide analyses ensured compliance with the food safety standards (light 301.9 ± 37.2 ppb; medium 126.1±19ppb; dark 107.9 ± 22.5ppb). Physico-chemical features were able to cluster samples from different origins within the same roasting level (α = 0.05). Results showed correlations (α = 0.01) between sensory analysis and physico-chemical values: direct for caffeine and astringency, reverse for perceived acidity in relation to astringency, roasted, dried fruits and nutty notes

Influence of Structural Defects on the Properties of Metamagnetic Shape Memory Alloys

The production of μ-particles of Metamagnetic Shape Memory Alloys by crushing and subsequent ball milling process has been analyzed. The high energy involved in the milling process induces large internal stresses and high density of defects with a strong influence on the martensitic transformation; the interphase creation and its movement during the martensitic transformation produces frictional contributions to the entropy change (exothermic process) both during forward and reverse transformation. The frictional contribution increases with the milling time as a consequence of the interaction between defects and interphases. The influence of the frictional terms on the magnetocaloric effect has been evidenced. Besides, the presence of antiphase boundaries linked to superdislocations helps to understand the spin-glass behavior at low temperatures in martensite. Finally, the particles in the deformed state were introduced in a photosensitive polymer. The mechanical damping associated to the Martensitic Transformation (MT) of the particles is clearly distinguished in the produced composite, which could be interesting for the development of magnetically-tunable mechanical dampers.This research was funded by Projects RTI2018-094683-B-C5 (4,5) (MCIU/AEI/FEDER,UE); ASACTEI Pcia.Santa Fe IO-2017-00138, PID-UNR ING 575 and ING 612 (2018–202

Metabolomics Combined with Sensory Analysis Reveals the Impact of Different Extraction Methods on Coffee Beverages from Coffea arabica and Coffea canephora var. Robusta

An untargeted metabolomics approach combined with sensory analysis was used to depict the impact of different traditional Italian extraction methods (i.e., Espresso, Neapolitan, Moka) along with Filter, on Coffea arabica and Coffea canephora var. robusta beverages. To this aim, polyphenols, Maillard reaction products, and coffee metabolites were screened by high resolution mass spectrometry and elaborated through both unsupervised and supervised multivariate statistical approaches. Multivariate statistics showed a distinctive chemical profile for Espresso preparation, while Moka and Neapolitan were very similar. The orthogonal projection to latent structures and discriminant analysis allowed the identification of 86 compounds showing a high VIP discrimination score (i.e., > 0.8). The 2,5-dimethyl-3-(methyldithio)-furan was a marker for the Filter preparation, while 1,2-disinapoylgentiobiose characterized both Filter and Neapolitan extractions. Caffeine (known to be a bitter compound) accumulated highly in Filter vs. Espresso, although at the sensory profile, bitterness was more perceived in Espresso. Vegetal aroma carried by pyrazines, pyridines, and phenolic acids were markers of Espresso, with Robusta showing higher values than Arabica. Notwithstanding, our findings showed that the extraction process played a hierarchically higher role in driving the chemical composition of the beverages when compared to coffee species