scholarly journals Changes in Quality Attributes During Storage of Litchi Juice Treated With Dimethyl Dicarbonate (DMDC) and Nisin

2015 ◽  
Vol 4 (4) ◽  
pp. 81 ◽  
Author(s):  
Huanli Guo ◽  
Yuanshan Yu ◽  
Gengsheng Xiao ◽  
Yujuan Xu ◽  
Jijun Wu

<p>The aim of this work was to evaluate the change in the quality of litchi juice treated by DMDC combined with Nisin during storage of 4 °C. Results found that addition of 250 mg/L of DMDC combined with 100 IU/mL of Nisin can ensure the microbiological safe of litchi juice during storage at 4 °C. Compare with heat treatment (95°C, 1 min), the treatment of DMDC combined with Nisin can retain a more value of sensory attributes, but a more loss in the content of total phenolics, ascorbic acid, and antioxidant capacity was observed during storage at 4 °C because of the ineffectiveness of DMDC and Nisin to the oxidase of litchi juice. Moreover, no significant change (<em>P </em>&gt; 0.05) was observed in the value of <em>L</em><em>∗</em>, <em>a</em><em>∗</em>, <em>b</em><em>∗</em>, and △E in the heat-treated litchi juice, and yet the litchi juice treated by DMDC and Nisin gradually turned into light red at the end of storage because of the oxidation of phenolics by residual POD in the litchi juice, which resulted in a significant changes (<em>P </em>&lt; 0.05) in the value of <em>L</em><em>∗</em>, <em>a</em><em>∗</em>, <em>b</em><em>∗</em>, and △E in the litchi juice. This study would provide technical support for commercial application of DMDC combined with Nisin in litchi juice processing.<strong></strong></p>

2009 ◽  
Vol 22 (1) ◽  
pp. 16-24 ◽  
Author(s):  
Maria Leonora Lotis D. Francisco ◽  
A.V.A. Resurreccion

Author(s):  
Michael F. P. Bifano ◽  
Pankaj B. Kaul ◽  
Vikas Prakash

Thermal conductivity measurements of commercially available CVD grown individual multiwalled carbon nanotubes (MWCNTs) are reported. The measurements are performed using the three-omega-based Wollaston T-Type probe method inside a scanning electron microscope (SEM). An average 385% increase in thermal conductivity is measured for those MWCNTs samples which undergo a 20 hour 3000°C post annealing heat treatment. However, in most samples qualitatively characterized defects are found to negate any advantage of the heat treatment process. The highest thermal conductivity measured is 893.0 W/mK and is of a heat-treated sample. These results will help to improve the quality of MWCNT production and aid in the development of highly efficient CNT-structured thermal management devices and engineering materials.


2017 ◽  
Vol 24 (3) ◽  
pp. 223-231 ◽  
Author(s):  
Mariana Rodríguez-Arzuaga ◽  
Andrea M Piagentini

Enzymatic browning affects the sensory and nutritional quality of fresh-cut apples and limits their shelf-life. Yerba mate ( Ilex paraguariensis), a plant widely consumed in South America as an infusion, could potentially be used in minimally processed fruits and vegetables as a natural additive to prevent browning, due to its high content of phenolic compounds with antioxidant capacity. The effects of the concentrations of ascorbic acid, citric acid, and yerba mate in an aqueous dipping solution on the instrumental color parameters, antioxidant capacity, and sensory quality of “Granny Smith” fresh-cut apples were modeled and the solution was optimized to obtain treated apples with maximum antioxidant capacity and minimum browning, without affecting the natural flavor of the fruits. The optimal composition obtained (1.2% yerba mate  + 0.9% citric acid + 1.0% ascorbic acid) increased the antioxidant capacity of the apples by 36%. The sensory acceptability test carried out on the “Granny Smith” fresh-cut apples treated with the optimal dipping solution showed that more than 78% of the surveyed consumers liked the color, flavor, and texture of the apples.


2016 ◽  
Vol 867 ◽  
pp. 19-23 ◽  
Author(s):  
Itsaree Iewkitthayakorn ◽  
Somjai Janudom ◽  
Narissara Mahathaninwong

This research focused on the effect of solution heat treated microstructures on anodic oxide formations of casting 7075 Al alloy. The casting specimens were solution heat treated at 450°C for various holding. The results showed that the quality of anodic oxide film on the specimen with 4h solution heat treatment time was higher than that of at other conditions. Because its microstructures obtained the lowest amounts of secondary phase particles leading to improve the quality of oxide film and also reduce defects in oxide film. On the other hand, coarse black particles of Mg2Si formed increasingly in microstructures of specimens after solution treatment at prolong holding time of 8h and 16h resulted in discontinues oxide films forming on them.


1994 ◽  
Vol 119 (1) ◽  
pp. 49-53 ◽  
Author(s):  
William S. Conway ◽  
Carl E. Sams ◽  
Chien Yi Wang ◽  
Judith A. Abbott

`Golden Delicious' apples (Malus domestics Borkh.) were treated with heat or CaCl2 solutions or a combination thereof to determine the effects of these treatments on decay and quality of fruit in storage. Heat treatment at 38C for 4 days, pressure infiltration with 2% or 4% solutions of CaCl2, or a combination of both, with heat following CaCl2 treatment affected decay and firmness during 6 months of storage at 0C. The heat treatment alone reduced decay caused by Botrytis cinerea (Pers.:Fr.) by ≈30%, while heat in combination with a 2% CaC12 solution reduced decay by ≈60 %. Calcium chloride solutions of 2% or 4% alone reduced decay by 40 % and 60 %, respectively. Heat treatments, either alone or in combination with CaC12 treatments, maintained firmness (80 N) best, followed by fruit infiltrated with 2% or 4% solutions of CaCl2 alone (70 N) and the nontreated controls (66 N). Instron Magness-Taylor and Instron compression test curves show that heat-treated fruit differed qualitatively and quantitatively from nonheated fruit. Heat treatment did not increase the amount of infiltrated Ca bound to the cell wall significantly, and a combination of heat treatment after CaCl2 infiltration increased surface injury over those fruit heated or infiltrated with CaCl2 solutions alone.


Author(s):  
Zsanett Bodor ◽  
Bianka Pergel ◽  
Csilla Benedek

AbstractThe high antioxidant capacity of tea is well-known, but the effect of flavorings like honey or lemon has been less studied. Their antioxidants can interact with each other, the global result being also affected by the brewing temperature.The combined effect of heat (55 and 80 °C) and flavorings (acacia and honeydew honeys, lemon juice) on the total polyphenol, total flavonoid content and antioxidant capacity of black and green teas was studied.In many cases higher antioxidant capacity was obtained at 80 °C. Teas flavored with honeydew honey had higher antioxidant capacity than those containing acacia honey. Addition of lemon decreased the antioxidant capacity of tea with honey. No synergies were confirmed in any of the compositions investigated. Vitamin C content of lemon-containing black tea was reduced by half at 80 °C compared to tea brewed at 55 °C; while honey was shown to partly prevent this loss of ascorbic acid.


Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1669 ◽  
Author(s):  
Alina Margean ◽  
Mirabela Ioana Lupu ◽  
Ersilia Alexa ◽  
Vasile Padureanu ◽  
Cristina Maria Canja ◽  
...  

In juice processing, ultrasound treatment has been tested as a potential alternative to conventional thermal methods to inactivate microorganisms and to enhance the nutritional status of juice. In this study, the impact of pasteurization and high-power ultrasound treatment on the quality of red grape juice was investigated in terms of the content of bioactive compounds such as phenolic compounds and l-ascorbic acid as well as regarding the microbiological and physicochemical properties. The grape juice was subjected to pasteurization (80 °C, 2 min) as well as to ultrasound treatment with an amplitude of 50 and 70% for 5 and 10 min. The results indicated the same level of total phenolic content for pasteurized and sonicated samples for 10 min with an amplitude of 70%, while the highest level of l-ascorbic acid was recorded for sonicated samples with an amplitude of 70% for 10 min. pH of sonicated samples decreased with amplitude and treatment time while total soluble solids and titratable acidity increased with amplitude and time. Moreover, the results indicated the usefulness of juice sonication to enhance the inactivation of microorganisms. Thus, the high-power ultrasound treatment might represent a viable technique to replace the conventional thermal treatment in grape juice processing.


2016 ◽  
Vol 687 ◽  
pp. 71-78
Author(s):  
Michał Najwer ◽  
Grzegorz Kwiatkowski

The article shows the results of research on tri-layer composite AA2519-AA1050-Ti Gr. 5 made by explosive cladding method. Performed bond was heat treated in different conditions. Four specimens were heated in 530°C in 30 minutes, and after adopted different ways of cooling for each specimen. Used cooling in air and water. Additionally two specimens were aged at 150°C for 600 minutes. Last joint was heated at 420°C for 60 minutes and after was cooled in still air. For obtained joint were performed mechanical and technological tests. Tests included tensile strength test, yield strength test, ram strength test and bend test. Moreover performed structural tests, analysis of the chemical composition and hardness measurements. Based on the results evaluated the quality of joint, and described the influence of heat treatment on the properties of obtained multilayer material. Was found that as a result of explosive cladding, hardness in the interface increased. Heat treatments at temperature 530°C do not change properties. Only the heat treatment at temperature 420°C is decreasing hardness in the interface and in the whole cross section of the AA2519 layer.


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