Color and Antioxidant Changes in Various Natural Rubber Processes

Fresh field natural rubber was coagulated by acetic acid, soaked in water at room temperature (WRT) or 70°C (W70) for 1 hr, and then dried in an oven at 40°C. Non-soaked natural rubber samples (NoW) served as a control. Two grades of natural rubber, namely air-dry sheet (ADS) and ribbed smoked sheet No.3 (RSS3) derived from the same latex, were also investigated. All dry rubber samples were characterized with Lovibond colorimeter according to ASTM D3157, as well as with a HunterLab spectrophotometer. Furthermore, all the dry rubber samples were dissolved in a chloroform:methanol mixture (4:1 v:v). The rubber was then precipitated out of the solution with methanol, and the remaining solution was quantitatively analyzed for total phenolic content (TPC). The plasticity retention index (PRI) was determined for all the dried rubber samples according to ASTM D3194. It was found that WRT, W70 and ADS were similar in lightness L*, while RSS3 had the lowest L*. W70 had the lowest redness a*, which increased in the order WRT, NoW, RSS3 and ADS. W70 also had the lowest yellowness b*, which increased in the order RSS3, NoW and WRT and ADS. Moreover, TPC was the lowest for the W70 sample, increasing in the order ADS, WRT, NoW and RSS3. The PRI was highest for W70, and decreased in the order WRT, RSS3, NoW and ADS. All of the PRI values observed were comparatively high relative to blocked standard Thai rubber 20 (STR20).

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Changes in Elderberry (Sambucus nigra L.) Juice Concentrate Polyphenols during Storage

Applied Sciences ◽

10.3390/app11156941 ◽

2021 ◽

Vol 11 (15) ◽

pp. 6941

Author(s):

Cláudia M. B. Neves ◽

António Pinto ◽

Fernando Gonçalves ◽

Dulcineia F. Wessel

Keyword(s):

Phenolic Compounds ◽

Chlorogenic Acid ◽

Total Phenolic Content ◽

Room Temperature ◽

Phenolic Content ◽

Total Phenolic ◽

Sambucus Nigra ◽

Juice Concentrate ◽

Rutin And Quercetin ◽

Polymeric Color

Elderberry (Sambucus nigra L.) juice concentrate is highly rich in polyphenols, particularly anthocyanins and flavonols, which have been associated with a wide range of health-promoting properties. Phenolic compounds, in particular anthocyanins, are unstable and may change during storage, which might influence the product color quality and its potential health effects. The aim of this study was to evaluate the changes in the polyphenols profile of elderberry juice concentrate produced at an industrial scale during seven months of storage at 5 °C and at room temperature. The total phenolic content, the total monomeric anthocyanins, the percent polymeric color, and the ABTS•+ scavenging activity were monitored over time. In addition, the profile and content of the main individual phenolic compounds were also assessed by HPLC-DAD. The results show that cyanidin-3-O-sambubioside, cyanidin-3-O-glucoside, cyanidin-3-O-sambubioside-5-O-glucoside, cyanidin-3,5-O-diglucoside, chlorogenic acid, rutin, and quercetin-3-O-glucoside were the main phenolic compounds identified. Storage at room temperature resulted in a strong reduction in total monomeric anthocyanin content accompanied by an increase in percent polymeric color values. Cyanidin-3-O-sambubioside and cyanidin-3-O-glucoside degraded faster than cyanidin-3,5-O-diglucoside and cyanidin-3-O-sambubioside-5-O-glucoside. Concentration of chlorogenic acid also decreased over storage, whereas rutin and quercetin-3-O-glucoside were quite stable. Storage at 5 °C caused a lower impact on the contents of anthocyanins and chlorogenic acid and the percent polymeric color was not affected. The total phenolic content and the in vitro antioxidant activity remained quite similar over the time, for both temperatures, suggesting that elderberry concentrates still preserve their health benefits of antioxidant capacity after seven months of storage.

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Effects of temperature, steeping time and particle size used in infusion brewing on total phenolic content and antioxidant activity of tea produced from young upland rice leaves

African Journal of Food, Agriculture, Nutrition and Development ◽

10.18697/ajfand.97.20150 ◽

2021 ◽

Vol 21 (02) ◽

pp. 17477-17491

Author(s):

Narissara Uthai ◽

Keyword(s):

Antioxidant Activity ◽

Total Phenolic Content ◽

Room Temperature ◽

Phenolic Content ◽

Antioxidant Activities ◽

Upland Rice ◽

Total Phenolic ◽

Antioxidant Power ◽

Surface Areas ◽

Young Leaves

Tea was brewed from young leaves of 4 weeks old Thai upland black waxy rice plants of the cultivar ‘Damgatondam’, which has a noticeable fragrant smell from both seeds and leaves. The plants were harvested about 1 cm above soil level, washed, and cut into pieces, about 1 cm long. These pieces were then steamed for 1 min in a steamer rack, withering for 5min by spreading them out in a thin layer, pan-roasted at 70°C for 30 min, and finally dried at 70°C for 90 min. They were either kept as pieces of leaves or ground into a powder, and both were used for brewing tea by infusion in water at 4oC, room temperature (about 25oC), for 1, 3, 5, 7, 9, 11, or 15 h and brewing at 70oC or 98oC for 1, 3, 5, 7, 9, 11 or 15 min. Directly after brewing, the tea was stored at -25oC awaiting analysis. Each sample was analyzed for total phenolic content (TPC) and for antioxidant activity, by ferric reducing antioxidant power (FRAP), 2,2 diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazo line-6-sulphonic acid) (ABTS) assays. Results showed that tea brewed from ground leaves had higher antioxidant activity than tea brewed from ungrounded leaves. The highest level of extraction was at 98oC for 15 min, where the TPC was 62.79 mg GAE/100g, antioxidant activity was 278.04 for DPPH, 195.38 for ABTS and 1150.13 mg TE/100g for FRAP. Samples extracted at 4oC or room temperature also had high levels of TPC and antioxidant activity with the maximum extraction at room temperature for 15 h; where TPC was 46.76 mg GAE/100g, and antioxidant activities were 152.72 for DPPH, 140.42 for ABTS and 950.32 mg TE/100 g for FRAP. Therefore, the level of extraction for tea brewed in all four conditions depended on both temperature and brewing time. Also, extraction of high levels of bioactive compounds depended on large surface areas of the leaves being in contact with water.

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Effect of Addition of Jackfruit Seed Flour on Nutrimental, Phytochemical and Sensory Properties of Snack Bar

Current Research in Nutrition and Food Science Journal ◽

10.12944/crnfsj.5.2.12 ◽

2017 ◽

Vol 5 (2) ◽

pp. 154-158 ◽

Cited By ~ 3

Author(s):

Sayooj Meethal ◽

Narinder Kaur ◽

Jyoti Singh ◽

Yogesh Gat

Keyword(s):

Antioxidant Activity ◽

Fatty Acid ◽

Free Fatty Acid ◽

Total Phenolic Content ◽

Room Temperature ◽

Phenolic Content ◽

Thiobarbituric Acid ◽

Sensory Properties ◽

Total Phenolic ◽

Seed Flour

Present study is undertaken with the aim of estimating quantitative changes in nutritional, phytochemical and sensory properties of snack bar. Nowadays consumers are more concerned about their health, so the need for the nutraceuticals has been increased. In view snack ball was prepared using varied concentrations of jackfruit seed flour and ragi in three different formulations. Present study also quantifies changes in thiobarbituric acid, free fatty acid, total phenolic content and antioxidant activity of snack bar packed in polypropylene and metalized polyester films and stored under room temperature conditions for 28 days of storage study. During storage at room temperature thiobarbituric acid and free fatty acid content were increased while total phenolic content and antioxidant activity were decreased with increase in temperature and progression of storage period. Maximum retention of phytochemicals was observed in the snack ball packed in polypropylene as compared to metalized polyester films and stored at room temperature conditions. Present study indicates potential application of jackfruit seed flour for preparation of low cost nutritious value added product.

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Effect of Vacuum and Non-Vacuum Packaging on Total Phenolic Content of Encapsulated Orthosiphon stamineus Spray-Dried Powder during Storage

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.280.330 ◽

2018 ◽

Vol 280 ◽

pp. 330-334

Author(s):

N.A. Razak ◽

Nasri A. Hamid ◽

Abdul Razak Shaari

Keyword(s):

Total Phenolic Content ◽

Room Temperature ◽

Phenolic Content ◽

Storage Period ◽

Vacuum Packaging ◽

Total Phenolic ◽

Total Phenolic Compound ◽

Different Temperatures ◽

Medicinal Properties ◽

Spray Dried

The experiment was conducted to determine the effects of vacuum and non-vacuum packaging on the total phenolic content of encapsulatedO.stamineusspray-dried powder when stored under different temperatures (10 and 25 °C) for 4 weeks of storage period. The total phenolic compound was measured using the Folin-Ciocalteu method and was analyzed using UV/VIS spectrophotometer. The results showed that both vacuum and non-vacuum packing affected the consistency of capsulatedO.stamineusspray-dried powder during storage. The total phenolic content of the samples significantly increased for both vacuum and non-vacuum packaging when stored at 10 °C. However, the total phenolic content of the samples for both vacuum and non-vacuum packaging decreased after 2 weeks of the storage period when the samples stored at room temperature, 25 °C. Thus, it is suggested to keep the encapsulatedO.stamineusspray-dried powder under low temperature (10 ˚) with vacuum packaging to sustain the medicinal properties quality and to prolong the shelf-life of the encapsulated products.

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Thai Rice Vinegars: Production and Biological Properties

Applied Sciences ◽

10.3390/app11135929 ◽

2021 ◽

Vol 11 (13) ◽

pp. 5929

Author(s):

Samuch Taweekasemsombut ◽

Jidapha Tinoi ◽

Pitchaya Mungkornasawakul ◽

Nopakarn Chandet

Keyword(s):

Antioxidant Activity ◽

Antibacterial Activity ◽

Acetic Acid ◽

Total Phenolic Content ◽

Phenolic Content ◽

Biological Properties ◽

Total Phenolic ◽

Glutinous Rice ◽

Ic50 Value ◽

Rice Vinegar

Four types of traditional Thai rice—polished, black fragrant, glutinous and black glutinous rice—were separately used as raw material for vinegar production. During alcohol fermentation, using enriched baker’s dried yeast (S. cerevisiae) as a starter culture gave the highest ethanol content over 7 days of fermentation. The conversion of ethanol to acetic acid for vinegar production by Acetobacter pasteurianus TISTR 102 was performed for 25 days. The highest amount of acetic acid was detected with glutinous rice fermentation (6.68% w/v). The biological properties of Thai rice vinegars were determined, including the total phenolic content, antioxidant activity, antibacterial activity and cytotoxicity. Black glutinous rice vinegar exhibited the maximum total phenolic content of 133.68 mg GAE/100 mL. This result was related to the antioxidative activity findings, for which black glutinous rice vinegar exhibited the strongest activity against both ABTS•+ and DPPH• radicals. Cytotoxicity against the human colon cancer cell line (HT-29) provided an IC50 value of 74.02 μg/mL and weak activity in a mouse fibroblast normal cell line (L929) with an IC50 value of 171.06 μg/mL. Glutinous rice vinegar was the most effective vinegar for inhibiting pathogenic bacterial growth of both Gram-negative and Gram-positive bacteria. These results suggested that the value of total phenolic content corresponded to the anticancer activity and antioxidant activity results, while antibacterial activity depended on the acidity of rice vinegar.

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Carotenoid Levels, Total Phenolic Content and Antioxidant Activity Variations in Varieties of Citrullus lanatus under Storage at Room Temperature

International Journal of Biochemistry Research & Review ◽

10.9734/ijbcrr/2016/22547 ◽

2016 ◽

Vol 9 (3) ◽

pp. 1-9 ◽

Cited By ~ 1

Author(s):

J Hena ◽

D Andala ◽

H Nyambaka ◽

M Nawiri

Keyword(s):

Antioxidant Activity ◽

Total Phenolic Content ◽

Room Temperature ◽

Phenolic Content ◽

Citrullus Lanatus ◽

Total Phenolic

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Analysis of Antioxidant Capacity and Antimicrobial Properties of Selected Polish Grape Vinegars Obtained by Spontaneous Fermentation

Molecules ◽

10.3390/molecules26164727 ◽

2021 ◽

Vol 26 (16) ◽

pp. 4727

Author(s):

Justyna Antoniewicz ◽

Karolina Jakubczyk ◽

Paweł Kwiatkowski ◽

Dominika Maciejewska-Markiewicz ◽

Joanna Kochman ◽

...

Keyword(s):

Acetic Acid ◽

Antioxidant Capacity ◽

Acid Content ◽

Total Phenolic Content ◽

Phenolic Content ◽

Antimicrobial Properties ◽

Total Phenolic ◽

Grape Variety ◽

Added Sugar ◽

Total Antioxidant

Nowadays, products of natural origin with health-promoting properties are increasingly more common. Research shows that fruit vinegars can be a source of compounds with antioxidant activity. Research on the total antioxidant capacity, total phenolic content, and antimicrobial properties against Staphylococcus aureus, Escherichia coli, and Candida albicans of grape vinegars were conducted. Moreover, gas chromatography was used to measure acetic acid content in the vinegars. The research material consisted of vinegars produced from five different grape varieties. For each variety, two variants were prepared: with and without the addition of sugar in the fermentation process. The highest antimicrobial activity against all micro-organisms was observed in vinegar produced from Solaris grapes with added sugar. The highest polyphenol content was observed in vinegar produced from the Prior grape variety with added sugar and the highest total antioxidant capacity is the Johanniter grape variety with added sugar. The vinegars examined in this study differed, depending on grape variety, in terms of antimicrobial properties, antioxidant capacity, total phenolic content, as well as acetic acid content. Sugar addition caused significant differences in the antioxidant capacity of vinegar samples.

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