scholarly journals Effect of the combined application of heat treatment and proteases on protein stability and volatile composition of Greek white wines

OENO One ◽  
2020 ◽  
Vol 54 (1) ◽  
pp. 175-188
Author(s):  
Piergiorgio Comuzzo ◽  
Sabrina Voce ◽  
Jacopo Fabris ◽  
Angelo Cavallaro ◽  
Gianmaria Zanella ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Protein Stability ◽  
Sodium Dodecyl ◽  
Protein Stabilization ◽  
Wine Aroma ◽  
Volatile Composition ◽  
White Wines ◽  
Aroma Profile ◽  
Rp Hplc ◽  
The Impact

Aim: This work evaluates the effects of the combined use of heat treatment (HT, 75 °C, 2 min) and proteases (P) on the protein stability and volatile composition of two white wines, obtained from the Greek cv. Assyrtiko and Moschofilero.Methods and results: Wine protein stabilization was assessed by heat test, using RP-HPLC determination of pathogenesis-related proteins (PRP) and by sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The impact of bentonite and P + HT treatment on wine aroma profile was evaluated by GC-MS with liquid–liquid extraction. According to the heat test, in Assyrtiko wine the level of stability achieved with P + HT was comparable with that obtained by bentonite fining and for Moschofilero wine – where protein instability was higher – bentonite was more efficient. RP-HPLC profiles showed that, in general, higher percentages of chitinases (CH) than thaumatin-like proteins (TLP) were removed by both bentonite and P + HT, with a similar efficiency for the two treatments and sometimes better performances for the latter. Conversely, TLP were removed more efficiently by bentonite, even if some fractions were eliminated to a slightly higher extent by proteases. In the conditions of the experiment, bentonite resulted in minor changes to the wine aroma profile. However, heating during protease treatment modified wine volatile composition, reducing the concentration of esters produced during fermentation while simultaneously increasing the contents of certain esters characteristic of aging such as ethyl lactate.Conclusions: The combination of proteases and heat treatment may be a promising technique for protein stabilization of wines. However, further investigations are needed to optimize the time:temperature ratio of the heat treatment in order to obtain the maximum protease activity and the minimum thermal deterioration of the wine quality.Significance and impact of the study: The results of this study have a practical interest for both the scientific community and wine sector, contributing to knowledge of the efficacy and limitations of the use of protease enzymes for wine stabilization.

Membrane protein stability depends on the concentration of compatible solutes – a single molecule force spectroscopic study

2013 ◽  
Vol 394 (11) ◽  
pp. 1465-1474 ◽  
Author(s):  
Arpita Roychoudhury ◽  
Adeline Bieker ◽  
Dieter Häussinger ◽  
Filipp Oesterhelt
Keyword(s):  
Membrane Protein ◽  
Protein Stability ◽  
Single Molecule ◽  
Protein Unfolding ◽  
Compatible Solutes ◽  
Protein Stabilization ◽  
Intramolecular Interactions ◽  
Organic Osmolytes ◽  
Dynamic Relationship ◽  
The Impact

Abstract Compatible solutes are small, uncharged, zwitter ionic, osmotically active molecules produced and accumulated by microorganisms inside their cell to counteract different kinds of environmental stress. They enhance protein stability without interfering with the metabolic pathways even at molar concentrations. In this paper, we report the stabilizing effects of compatible solutes, ectoine, betaine and taurine on membrane protein bacteriorhodopsin at different concentrations. Using atomic force microscopy based single molecule force spectroscopy the impact of the osmolytes was quantified by measuring the forces required to pull the protein out of the membrane and the change in the persistence lengths of the unfolded polypeptide chain. Increase in unfolding forces were observed, indicating the strengthening of intramolecular interactions, which are vital for protein stability. The decrease in persistence lengths was recorded and showed increasing tendencies of the polypeptide strand to coil up. Interestingly, it was revealed that these molecules have different stabilizing effects on protein unfolding at different concentrations. The results show that the unfolding of single protein provides insight to the structure-dynamic relationship between the protein and compatible solute molecules at sub-nanometer scale. This also helps to understand the molecular mechanism involved in protein stabilization by organic osmolytes.

scholarly journals Pre-fermentation heat treatment: a multitool technique to keep the pot boiling

2021 ◽  
Author(s):  
Olivier Geffroy ◽  
Carole Feilhès ◽  
Jean-Luc Favarel ◽  
Ricardo Lopez
Keyword(s):  
Heat Treatment ◽  
Consumer Demand ◽  
Wine Aroma ◽  
Research Results ◽  
The Impact

First industrially developed in the 1970s to process botrytised grapes, the pre-fermentation heat treatment of grapes is becoming more and more popular to produce fruit-driven wines. Several conditions, such as the time and the temperature of heating or the conditions of fermentation itself, have been proposed to modulate the aroma of thermovinified wines and adapt their profile to consumer demand. Based on research results obtained during the last decade, this article provides a short, up-to-date review of the impact of this technique on wine aroma.

scholarly journals Rootstock Effect on Volatile Composition of Albariño Wines

2021 ◽  
Vol 11 (5) ◽  
pp. 2135
Author(s):  
Mar Vilanova ◽  
Zlatina Genisheva ◽  
Miguel Tubío ◽  
Katia Alvarez ◽  
José Ramón Lissarrague ◽  
...  
Keyword(s):  
Carbonyl Compounds ◽  
Volatile Fatty Acids ◽  
Positive Influence ◽  
Ethyl Esters ◽  
Wine Aroma ◽  
Volatile Composition ◽  
Volatile Phenols ◽  
New Information ◽  
Berry Quality ◽  
The Impact

Background: Rootstock is a viticultural practice used to combat the devastating Phylloxera vitifoliae (Fitch). Additionally, it is well-known that wine aroma composition depends mainly on variety, viticulture management and winemaking; therefore, rootstocks can affect to berry quality. This study evaluated the influence of nine rootstocks (110R, SO4, 196-17C, Riparia G, 161-49C, 420A, Gravesac, 3309C and 41B) on volatile composition of Albariño wine in two consecutive vintages. Material and Methods: Volatile compounds belonging to eight groups (alcohols, C6-compounds, ethyl esters+acetates, terpenes + C13-norisoprenoids, volatile phenols, volatile acids, lactones and carbonyl compounds) were determined in Albariño wines by GC–MS, during 2009 and 2010 vintages. Results: Rootstock 110R had a positive influence on Albariño wines, increasing total volatile concentration, due mainly to 2-phenylethanol, decanoic and hexanoic acids, ethyl esters and acetates, and C13-norisoprenoids. However, the higher contribution of volatile fatty acids to Albariño wine was shown when grapevines were grafted onto SO4. Conclusions: This work provides new information about the impact of rootstocks on Albariño wine volatile composition, where 110R had a positive influence on Albariño wines under the edaphoclimatic conditions of Salnés Valley (Galicia, Spain).

Microstructural and Mechanical Behaviour Evaluation of Mg-Al-Zn Alloy Friction Stir Welded Joint

2020 ◽  
Vol 17 (3) ◽  
pp. 8150-8159
Author(s):  
Kulwant Singh ◽  
Gurbhinder Singh ◽  
Harmeet Singh
Keyword(s):  
Heat Treatment ◽  
Friction Stir Welding ◽  
Magnesium Alloys ◽  
Mechanical Performance ◽  
Fuel Efficiency ◽  
Research Work ◽  
Grain Structure ◽  
Tensile Fracture ◽  
Friction Stir ◽  
The Impact

The weight reduction concept is most effective to reduce the emissions of greenhouse gases from vehicles, which also improves fuel efficiency. Amongst lightweight materials, magnesium alloys are attractive to the automotive sector as a structural material. Welding feasibility of magnesium alloys acts as an influential role in its usage for lightweight prospects. Friction stir welding (FSW) is an appropriate technique as compared to other welding techniques to join magnesium alloys. Field of friction stir welding is emerging in the current scenario. The friction stir welding technique has been selected to weld AZ91 magnesium alloys in the current research work. The microstructure and mechanical characteristics of the produced FSW butt joints have been investigated. Further, the influence of post welding heat treatment (at 260 °C for 1 h) on these properties has also been examined. Post welding heat treatment (PWHT) resulted in the improvement of the grain structure of weld zones which affected the mechanical performance of the joints. After heat treatment, the tensile strength and elongation of the joint increased by 12.6 % and 31.9 % respectively. It is proven that after PWHT, the microhardness of the stir zone reduced and a comparatively smoothened microhardness profile of the FSW joint obtained. No considerable variation in the location of the tensile fracture was witnessed after PWHT. The results show that the impact toughness of the weld joints further decreases after post welding heat treatment.

An Approach of the Madeira Wine Chemistry

Beverages ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 12 ◽  
Author(s):  
Rosa Perestrelo ◽  
Catarina Silva ◽  
Carolina Gonçalves ◽  
Mariangie Castillo ◽  
José S. Câmara
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Least Squares ◽  
Partial Least Squares ◽  
Chemical Reactions ◽  
Ageing Process ◽  
Gas Chromatography Mass Spectrometry ◽  
Wine Aroma ◽  
Least Squares Regression ◽  
Volatile Composition

Madeira wine is a fortified Portuguese wine, which has a crucial impact on the Madeira Island economy. The particular properties of Madeira wine result from the unique and specific winemaking and ageing processes that promote the occurrence of chemical reactions among acids, sugars, alcohols, and polyphenols, which are important to the extraordinary quality of the wine. These chemical reactions contribute to the appearance of novel compounds and/or the transformation of others, consequently promoting changes in qualitative and quantitative volatile and non-volatile composition. The current review comprises an overview of Madeira wines related to volatile (e.g., terpenes, norisoprenoids, alcohols, esters, fatty acids) and non-volatile composition (e.g., polyphenols, organic acids, amino acids, biogenic amines, and metals). Moreover, types of aroma compounds, the contribution of volatile organic compounds (VOCs) to the overall Madeira wine aroma, the change of their content during the ageing process, as well as the establishment of the potential ageing markers will also be reviewed. The viability of several analytical methods (e.g., gas chromatography-mass spectrometry (GC-MS), two-dimensional gas chromatography and time-of-flight mass spectrometry (GC×GC-ToFMS)) combined with chemometrics tools (e.g., partial least squares regression (PLS-R), partial least squares discriminant analysis (PLS-DA) was investigated to establish potential ageing markers to guarantee the Madeira wine authenticity. Acetals, furanic compounds, and lactones are the chemical families most commonly related with the ageing process.

scholarly journals How Different Fermentation Type Affects Volatile Composition of Plum Jerkums

2021 ◽  
Vol 11 (10) ◽  
pp. 4658
Author(s):  
Magdalena Januszek ◽  
Paweł Satora
Keyword(s):  
Volatile Compounds ◽  
Current Paper ◽  
Higher Alcohols ◽  
High Quality ◽  
Volatile Composition ◽  
Spontaneous Fermentation ◽  
Fermentation Efficiency ◽  
Yeast Strains ◽  
The Impact

Quality of plum jerkum is significantly associated to the profile of volatile compounds. Therefore, we decided to assess the impact of various fermentation types on selected properties of plum jerkums, especially compounds which contribute to the aroma of the finished product. We used the following yeast strains: S. cerevisiae S1, H. uvarum H2, and Ethanol RED (S. cerevisiae). Moreover, we considered spontaneous fermentation. S. cerevisiae and H. uvarum strains were isolated during the fermentation of Čačanska Lepotica or Węgierka Dąbrowicka (plum cultivars), respectively. As for fermentation type, spontaneous fermentation of H. uvarum H2 provided the best results. It could be associated to the fact that plum juices fermented with H. uvarum H2 presented the highest concentration of terpenoids, esters, or some higher alcohols. In the current paper, application of indigenous strains of yeasts resulted in the required oenological characteristics, e.g., highest fermentation efficiency and concentration of ethanol was determined in juices fermented with Ethanol RED (S. cerevisiae) and also with S. cerevisiae S1. Our results suggested that indigenous strains of yeasts present in plums demonstrate great potential for the production of plum jerkums of high quality.

scholarly journals Impact of the Simulated Gastric Digestion Methodology on the In Vitro Intestinal Proteolysis and Lipolysis of Emulsion Gels

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 321
Author(s):  
Camila Mella ◽  
Michelle Quilaqueo ◽  
Rommy N. Zúñiga ◽  
Elizabeth Troncoso
Keyword(s):  
Heat Treatment ◽  
Protein Isolate ◽  
Gastric Digestion ◽  
Human Gastrointestinal Tract ◽  
Gel Structure ◽  
Intestinal Digestion ◽  
Food Digestion ◽  
The Impact ◽  
Digestion Methods

The aim of this work was to study the impact of the methodology of in vitro gastric digestion (i.e., in terms of motility exerted and presence of gastric emptying) and gel structure on the degree of intestinal proteolysis and lipolysis of emulsion gels stabilized by whey protein isolate. Emulsions were prepared at pH 4.0 and 7.0 using two homogenization pressures (500 and 1000 bar) and then the emulsions were gelled by heat treatment. These gels were characterized in terms of texture analysis, and then were subjected to one of the following gastric digestion methods: in vitro mechanical gastric system (IMGS) or in vitro gastric digestion in a stirred beaker (SBg). After gastric digestion, the samples were subjected to in vitro intestinal digestion in a stirred beaker (SBi). Hardness, cohesiveness, and chewiness were significantly higher in gels at pH 7.0. The degree of proteolysis was higher in samples digested by IMGS–SBi (7–21%) than SBg–SBi (3–5%), regardless of the gel’s pH. For SBg–SBi, the degree of proteolysis was not affected by pH, but when operating the IMGS, higher hydrolysis values were obtained for gels at pH 7.0 (15–21%) than pH 4.0 (7–13%). Additionally, the percentage of free fatty acids (%FFA) released was reduced by 47.9% in samples digested in the IMGS–SBi. For the methodology SBg–SBi, the %FFA was not affected by the pH, but in the IMGS, higher values were obtained for gels at pH 4.0 (28–30%) than pH 7.0 (15–19%). Our findings demonstrate the importance of choosing representative methods to simulate food digestion in the human gastrointestinal tract and their subsequent impact on nutrient bioaccessibility.

scholarly journals Effect of Heat Treatment by the Sous-Vide Method on the Quality of Poultry Meat

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1610
Author(s):  
Wiesław Przybylski ◽  
Danuta Jaworska ◽  
Katarzyna Kajak-Siemaszko ◽  
Piotr Sałek ◽  
Kacper Pakuła
Keyword(s):  
Heat Treatment ◽  
Sensory Quality ◽  
Treatment Method ◽  
Poultry Meat ◽  
Chicken Breast ◽  
Breast Meat ◽  
Sous Vide ◽  
The Impact ◽  
Cooked Meat

An increase in the consumption of poultry meat has been observed due to its availability, nutritional value, and delicate flavor. These characteristics make it possible to prepare, with the use of spices and other additives, many different dishes and products for increasingly demanding consumers. The sous-vide technique is increasingly being used to give new sensory attributes to dishes in gastronomy. The study aimed to assess the impact of the heat treatment method, i.e., the sous-vide method, as compared to traditional cooking, on the sensory quality of poultry meat, as well as the efficiency of the process with regard to technological quality. The cooking yield with the sous-vide method of processing poultry meat was higher than with the traditional method of cooking in water (88.5% vs. 71.0%, respectively). The meat was also found to be redder (a* = 254 vs. 074) and less yellow (b* = 1512 vs. 1649), as well as more tender. The sensory quality of chicken breast meat obtained by the sous-vide method was higher in terms of attributes such as color tone, tenderness, juiciness, and overall quality. At the same time, it was lower in terms of the odor of cooked meat and the flavor of cooked meat as compared to meat subjected to traditional cooking.

scholarly journals The effect of heat treatment and impact angle on the erosion behavior of nickel-tungsten carbide cold spray coating using response surface methodology

2021 ◽  
Author(s):  
Marios Kazasidis ◽  
Elisa Verna ◽  
Shuo Yin ◽  
Rocco Lupoi
Keyword(s):  
Heat Treatment ◽  
Response Surface Methodology ◽  
Mass Loss ◽  
Tungsten Carbide ◽  
Response Surface ◽  
Spray Coating ◽  
Impact Angle ◽  
Control Factors ◽  
Heat Treated ◽  
The Impact

AbstractThis study elucidates the performance of cold-sprayed tungsten carbide-nickel coating against solid particle impingement erosion using alumina (corundum) particles. After the coating fabrication, part of the specimens followed two different annealing heat treatment cycles with peak temperatures of 600 °C and 800 °C. The coatings were examined in terms of microstructure in the as-sprayed (AS) and the two heat-treated conditions (HT1, HT2). Subsequently, the erosion tests were carried out using design of experiments with two control factors and two replicate measurements in each case. The effect of the heat treatment on the mass loss of the coatings was investigated at the three levels (AS, HT1, HT2), as well as the impact angle of the erodents (30°, 60°, 90°). Finally, the response surface methodology (RSM) was applied to analyze and optimize the results, building the mathematical models that relate the significant variables and their interactions to the output response (mass loss) for each coating condition. The obtained results demonstrated that erosion minimization was achieved when the coating was heat treated at 600 °C and the angle was 90°.

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