scholarly journals Alternative Methods for Measuring the Susceptibility of White Wines to Pinking Alteration: Derivative Spectroscopy and CIEL*a*b* Colour Analysis

Foods ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 553
Author(s):  
Fabrizio Minute ◽  
Federico Giotto ◽  
Luís Filipe-Ribeiro ◽  
Fernanda Cosme ◽  
Fernando M. Nunes
Keyword(s):  
B Value ◽  
White Wine ◽  
Alternative Methods ◽  
White Wines ◽  
First Derivative ◽  
Derivative Spectra ◽  
A Value ◽  
Derivative Spectroscopy ◽  
Reducing Conditions ◽  
Second Derivative Spectra

Pinking is the term used for describing the pink colouration that appears in white wines produced under reducing conditions when oxidised. The ability to predict the susceptibility of white wines for pinking is of utmost importance for wine producers. In this work, we critically compare the two most currently used methods for measuring pinking susceptibility and the use of the first derivative spectra and the CIEL*a*b* colour space method. The amplitude of the first derivative spectra in the 450–550 nm range has a good correlation with the values obtained by subtracting the extrapolate background at 500 nm (R2 = 0.927); therefore, first derivative spectroscopy seems to be a more straightforward approach for eliminating the background problem that occurs in this method. The CIEL*a*b* method using the a* value after oxidation seems to be the most appropriate method to measure the pinking susceptibility of white wines, showing a very good correlation with the amplitude of the first derivative spectra. The pink colouration visualisation is linearly related to the b* value of the white wine, showing that no universal cut-off value for predicting the pink visualisation should be used. Second derivative spectra allow the observation of the formation of different chromophores in wines after induced oxidation.

scholarly journals Simultaneous Determination of Metoprolol-Hydrochlorothiazide and Propranolol-Hydrochlorothiazide in Combined Formulations by Derivative Spectroscopy

1997 ◽  
Vol 80 (2) ◽  
pp. 325-330 ◽  
Author(s):  
Challapalli V N Prasad ◽  
Vipin Bharadwaj ◽  
Vidya Narsimhan ◽  
Rama T Chowdhary ◽  
Pyare Parimoo
Keyword(s):  
Simultaneous Determination ◽  
Second Derivative ◽  
Zero Crossing ◽  
Derivative Spectra ◽  
Derivative Spectroscopy ◽  
Naoh Solution ◽  
Compensation Technique ◽  
Second Derivative Spectra ◽  
Crossing Point

Abstract A derivative spectrophotometric procedure was established for simultaneous determination of propranolol HCI (PP) with hydrochlorothiazide (HTZ) and metoprolol tartrate (MTP) with HTZ in tablet preparations. The method uses first- and second-derivative spectra of tablet extract in 0.01 N NaOH solution. Ratios of analyte concentrations in the mixture were determined by the compensation technique. The zero-crossing point (ZCP) was also used to estimate the amounts of PP and HTZ in the formulations, and results were compared with those from the compensation technique. The results were found to be precise and free from interferences.

Second‐Derivative Spectra for Estimating Crop Residue Cover

1994 ◽  
Vol 86 (2) ◽  
pp. 349-354 ◽  
Author(s):  
Haiping Su ◽  
Michel D. Ransom ◽  
Edward T. Kanemasu ◽  
Tanvir H. Demetriades‐Shah
Keyword(s):  
Crop Residue ◽  
Second Derivative ◽  
Derivative Spectra ◽  
Second Derivative Spectra

scholarly journals Effects of Camu-Camu (Myrciaria dubia) Powder on the Physicochemical and Kinetic Parameters of Deteriorating Microorganisms and Salmonella enterica Subsp. enterica Serovar Typhimurium in Refrigerated Vacuum-Packed Ground Beef

Agriculture ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 252
Author(s):  
Jorge Luiz da Silva ◽  
Vasco Cadavez ◽  
José M. Lorenzo ◽  
Eduardo Eustáquio de Souza Figueiredo ◽  
Ursula Gonzales-Barron
Keyword(s):  
Ground Beef ◽  
Treated Group ◽  
B Value ◽  
Kinetics Parameters ◽  
Psychrotrophic Bacteria ◽  
Color Changes ◽  
A Value ◽  
Spoilage Bacteria ◽  
Serovar Typhimurium ◽  
And Control

This study aims to evaluate the effects of camu-camu powder (CCP), Amazonian berry fruit with documented bioactive properties, physicochemical meat parameters, and the growth kinetics parameters of S. enterica ser. Typhimurium, psychrotrophic bacteria (PSY), and lactic acid bacteria (LAB) in vacuum-packed ground beef. Batches of ground beef were mixed with 0.0%, 2.0%, 3.5%, and 5.0% CCP (w/w), vacuum-packed as 10 g portions, and stored at 5 °C for 16 days. Centesimal composition analyses (only on the initial day), pH, TBARS, and color were quantified on storage days 1, 7, and 15, while PSY and LAB were counted on days 0, 3, 6, 9, 13, and 16. Another experiment was conducted with the same camu-camu doses by inoculating S. enterica ser. Typhimurium microbial kinetic curves were modeled by the Huang growth and Weibull decay models. CCP decreased TBARS in beef from 0.477 to 0.189 mg MDA·kg−1. No significant differences in meat pH between treated and control samples were observed on day 15. CCP addition caused color changes, with color a* value decreases (from 14.45 to 13.44) and color b* value increases (from 17.41 to 21.25), while color L* was not affected. Higher CCP doses caused progressive LAB growth inhibition from 0.596 to 0.349 log CFU·day−1 at 2.0% and 5.0% CCP, respectively. Similarly, PSY growth rates in the treated group were lower (0.79–0.91 log CFU·day−1) compared to the control (1.21 log CFU·day−1). CCP addition at any of the investigated doses produced a steeper S. enterica ser. Typhimurium inactivation during the first cold storage day, represented by Weibull’s concavity α shape parameter, ranged from 0.37 to 0.51, in contrast to 1.24 for the control. At the end of the experiment, however, S. enterica ser. Typhimurium counts in beef containing CCP were not significantly different (p < 0.05) from the control. Although CCP affects bacterial kinetics, it does not protect ground beef against spoilage bacteria and Salmonella to the same degree it does against lipid peroxidation.

scholarly journals Effect of Pre-Fermentative Maceration and Fining Agents on Protein Stability, Macromolecular, and Phenolic Composition of Albariño White Wines: Comparative Efficiency of Chitosan, k-Carrageenan and Bentonite as Heat Stabilisers

Foods ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 608
Author(s):  
Inma Arenas ◽  
Miguel Ribeiro ◽  
Luís Filipe-Ribeiro ◽  
Rafael Vilamarim ◽  
Elisa Costa ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Protein Stability ◽  
White Wine ◽  
The Other ◽  
White Wines ◽  
Comparative Efficiency ◽  
Fining Agents ◽  
Protein Instability ◽  
Related Proteins ◽  
Protein Stabilisation

In this work, the effect of pre-fermentative skin maceration (PFSM) on the chemical composition of the macromolecular fraction, polysaccharides and proteins, phenolic compounds, chromatic characteristics, and protein stability of Albariño monovarietal white wines was studied. PFSM increased the extraction of phenolic compounds and polysaccharides and reduced the extraction of pathogenesis-related proteins (PRPs). PFSM wine showed significantly higher protein instability. Sodium and calcium bentonites were used for protein stabilisation of wines obtained with PFSM (+PFSM) and without PFSM (−PFSM), and their efficiencies compared to fungal chitosan (FCH) and k-carrageenan. k-Carrageenan reduced the content of PRPs and the protein instability in both wines, and it was more efficient than sodium and calcium bentonites. FCH was unable to heat stabilise both wines, and PRPs levels remained unaltered. On the other hand, FCH decreased the levels of wine polysaccharides by 60%. Sodium and calcium bentonite also decreased the levels of wine polysaccharides although to a lower extent (16% to 59%). k-Carrageenan did not affect the wine polysaccharide levels. Overall, k-carrageenan is suitable for white wine protein stabilisation, having a more desirable impact on the wine macromolecular fraction than the other fining agents, reducing the levels of the wine PRPs without impacting polysaccharide composition.

scholarly journals Characterisation of Extracts Obtained from Unripe Grapes and Evaluation of Their Potential Protective Effects against Oxidation of Wine Colour in Comparison with Different Oenological Products

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1499
Author(s):  
Giovanna Fia ◽  
Ginevra Bucalossi ◽  
Bruno Zanoni
Keyword(s):  
Antioxidant Activity ◽  
Red Wine ◽  
Waste Product ◽  
Natural Antioxidants ◽  
White Wine ◽  
Small Scale ◽  
Protective Effects ◽  
White Wines ◽  
Accelerated Oxidation ◽  
Wine Colour

Unripe grapes (UGs) are a waste product of vine cultivation rich in natural antioxidants. These antioxidants could be used in winemaking as alternatives to SO2. Three extracts were obtained by maceration from Viognier, Merlot and Sangiovese UGs. The composition and antioxidant activity of the UG extracts were studied in model solutions at different pH levels. The capacity of the UG extracts to protect wine colour was evaluated in accelerated oxidation tests and small-scale trials on both red and white wines during ageing in comparison with sulphur dioxide, ascorbic acid and commercial tannins. The Viognier and Merlot extracts were rich in phenolic acids while the Sangiovese extract was rich in flavonoids. The antioxidant activity of the extracts and commercial tannins was influenced by the pH. In the oxidation tests, the extracts and commercial products showed different wine colour protection capacities in function of the type of wine. During ageing, the white wine with the added Viognier UG extract showed the lowest level of colour oxidation. The colour of the red wine with the UG extract evolved similarly to wine with SO2 and commercial tannins. The obtained results indicated that natural and healthy UG extracts could be an interesting substitute for SO2 during wine ageing.

scholarly journals First Derivative UV Spectra of Surface Water as a Monitor of Chlorination in Drinking Water Treatment

2001 ◽  
Vol 1 ◽  
pp. 39-43 ◽  
Author(s):  
V. Zitko
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Surface Water ◽  
Distribution System ◽  
Drinking Water Treatment ◽  
Uv Spectra ◽  
Free Chlorine ◽  
Residual Chlorine ◽  
First Derivative ◽  
Derivative Spectra

Many countries require the presence of free chlorine at about 0.1 mg/l in their drinking water supplies. For various reasons, such as cast-iron pipes or long residence times in the distribution system, free chlorine may decrease below detection limits. In such cases it is important to know whether or not the water was chlorinated or if nonchlorinated water entered the system by accident. Changes in UV spectra of natural organic matter in lakewater were used to assess qualitatively the degree of chlorination in the treatment to produce drinking water. The changes were more obvious in the first derivative spectra. In lakewater, the derivative spectra have a maximum at about 280 nm. This maximum shifts to longer wavelengths by up to 10 nm, decreases, and eventually disappears with an increasing dose of chlorine. The water treatment system was monitored by this technique for over 1 year and changes in the UV spectra of water samples were compared with experimental samples treated with known amounts of chlorine. The changes of the UV spectra with the concentration of added chlorine are presented. On several occasions, water, which received very little or no chlorination, may have entered the drinking water system. The results show that first derivative spectra are potentially a tool to determine, in the absence of residual chlorine, whether or not surface water was chlorinated during the treatment to produce potable water.

scholarly journals Comparison of a Rapid Light-Induced and Forced Test to Study the Oxidative Stability of White Wines

Molecules ◽  
2022 ◽  
Vol 27 (1) ◽  
pp. 326
Author(s):  
Emilio Celotti ◽  
Georgios Lazaridis ◽  
Jakob Figelj ◽  
Yuri Scutaru ◽  
Andrea Natolino
Keyword(s):  
Oxidative Stability ◽  
Oxidation Stability ◽  
White Wine ◽  
Sensorial Analysis ◽  
White Wines ◽  
Technological Interventions ◽  
Prototype Instrument ◽  
Fast Decision ◽  
Effect Of Light

The oxidation processes of white wines can occur during storage and commercialization due to several factors, and these can negatively affect the color, aroma, and quality of the wine. Wineries should have faster and simpler methods that provide valuable information on oxidation stability of wines and allow fast decision-making procedures, able to trigger suitable technological interventions. Using a portable prototype instrument for light irradiations at different wavelengths and times was considered and evaluated on sensorial, spectrophotometric, and colorimetric parameters of white wines. The sensorial analysis revealed that white and light blue were the most significant, after only 1 h of irradiation. The experimental results showed that hydrogen peroxide could enhance the effect of light treatment, allowing a contemporary evaluation of the oxidation stability of wine against light and chemical stresses. As expected, a good correlation (R2 > 0.89) between optical density at 420 nm and b* parameter was highlighted. The synergic effect of light and H2O2 was also studied on the hydrolyzable and condensed tannins’ additions to white wine. The proposed methodology could be used to evaluate the oxidative stability of white wines, but also to evaluate the effect of some oenological adjuvants on wine stability.

scholarly journals The effect of enriched cyclopoid copepods on the coloration and feeding rate of Betta splendens

2021 ◽  
Vol 869 (1) ◽  
pp. 012007
Author(s):  
A Yuslan ◽  
N Nasir ◽  
H Suhaimi ◽  
A Arshad ◽  
N W Rasdi
Keyword(s):  
Rice Bran ◽  
Feeding Rate ◽  
Effective Means ◽  
B Value ◽  
Proximate Analysis ◽  
Betta Splendens ◽  
A Value ◽  
Wide Range ◽  
Significant Difference ◽  
L Value

Abstract Copepods with a wide range of sizes, species, and nutritional compositions are preferred as live food for rearing of Betta splendens larvae. This research focuses on evaluating the efficiency of copepod enrichment diets in improving the coloration and feeding rate of B. splendens. Copepod were enriched with Chlorella sp. (T1), capsicum (T2), mixed vegetable (carrot + spinach), (T3), yeast (T4) and rice bran (T5) in 24 hours prior the feeding tests. As a result, proximate analysis of enriched-copepods showed that T1 (70.88±0.41) has highest protein content and T5 (22.01±0.59) has the highest lipid content. The specific growth rate and survival rate of B. splendens was highest in the treatment T1 (2.56±0.07%; 91.11±1.92%) and followed closely by T3 (2.49±0.51%; 85.55±8.39%). Feeding rate, T3 (70.08±3.88%) presented highest rate compared to other treatments. The different enrichment diets used were significantly impact the coloration test on body of L* value (P=0.001, P<0.05), T3 (66.11±3.60) appeared darker in color in contrast to others. As for a* value, the coloration was not impacted with the use of different enrichment on copepods (P=0.158, P>0.05) was detected for T1 (2.84±0.73) that gave a redder shade than other treatments did. T3 (2.40±0.30) exerted a more yellowish shade than the rest for b* value with a significant difference (P=0.015, P<0.05). The current study demonstrates that, rice bran, capsicum and mixed vegetable enrichment (carrot and spinach) have the potential to be an effective means of increasing B. splendens coloring and feeding rate. This potential diet can be further used as a substitution to artificial foods in producing sustainable culture of ornamental fish in the aquaculture industry.

scholarly journals Pengaruh Lokasi Geografis dan Vegetasi terhadap Sifat Fisikokimia Madu dari Ciwidey dan Bogor

2020 ◽  
Vol 1 (2) ◽  
pp. 71
Author(s):  
Emanuela Rae Alodia ◽  
Anas Bunyamin ◽  
Efri Mardawati
Keyword(s):  
Physicochemical Properties ◽  
Water Content ◽  
Sugar Content ◽  
Geographical Location ◽  
B Value ◽  
Reducing Sugar ◽  
National Standard ◽  
Color Analysis ◽  
A Value ◽  
C Value

<p><em>Physicochemical properties are one of the parameters of honey quality that impacts the sales of honey as well as the economy condition of the society in Ciwidey and Bogor. The physicochemical properties of honey are significantly influenced by the origin of the honey, including its geographical location and vegetation. This study aims to determine the physicochemical properties between multiflora honey from Ciwidey and Bogor with different source of nectar where Ciwidey honey is dominated by calliandra nectar while Bogor honey is dominated by kapok nectar. Data were analyzed with descriptive and quantitative method using independent t test for data with normal distribution (water content and reducing sugar content). Data that were not normally distributed (color analysis and acidity value) were tested non-parametrically with the Mann Whitney-U. The results showed that Bogor honey has the better physicochemical properties and meets Indonesian National Standard (Standar Nasional Indonesia, SNI) 8664:2018, with a water content of 15.15% w/w, L* values of 35.26, a* value of 28.66, b* value of 59.46, c* value of 66.01, h* value of 64.27°, reducing sugar content of 78.78% and acidity value of 35.56 mL NaOH kg-1. Phytochemical screening showed positive results on alkaloid, flavonoid, phenol and tannin, and the results of GC-MS analysis showed three significant compounds which are hydroxymethylfurfural of 48.26%, levoglucosan of 13.58% and ammonium carbamate of 9.18%.</em></p>

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