Phenolics and polyphenolics in foods, beverages and spices: Antioxidant activity and health effects – A review

Xylanases are hydrolytic enzymes which randomly cleave the β 1,4 backbone of the complex plant cell wall polysaccharide xylan. Diverse forms of these enzymes exist, displaying varying folds, mechanisms of action, substrate specificities, hydrolytic activities (yields, rates and products) and physicochemical characteristics. Research has mainly focused on only two of the xylanase containing glycoside hydrolase families, namely families 10 and 11, yet enzymes with xylanase activity belonging to families 5, 7, 8 and 43 have also been identified and studied, albeit to a lesser extent. Driven by industrial demands for enzymes that can operate under process conditions, a number of extremophilic xylanases have been isolated, in particular those from thermophiles, alkaliphiles and acidiphiles, while little attention has been paid to cold-adapted xylanases. Here, the diverse physicochemical and functional characteristics, as well as the folds and mechanisms of action of all six xylanase containing families will be discussed. The adaptation strategies of the extremophilic xylanases isolated to date and the potential industrial applications of these enzymes will also be presented.

Xylanases, xylanase families and extremophilic xylanases

Despite an increased knowledge of microbial xylanolytic systems in the past few years, further studies are required to achieve a complete understanding of the mechanism of xylan degradation by microorganisms and their enzymes. The enzyme system used by microbes for the metabolism of xylan is the most important tool for investigating the use of the second most abundant polysaccharide (xylan) in nature. Recent studies on microbial xylanolytic systems have generally focussed on induction of enzyme production under different conditions, purification, characterization, molecular cloning and expression, and use of enzyme predominantly for pulp bleaching. Rationale approaches to achieve these goals require a detailed knowledge of the regulatory mechanism governing enzyme production. This review will focus on complex xylan structure and the microbial enzyme complex involved in its complete breakdown, studies on xylanase regulation and production and their potential industrial applications, with special reference to biobleaching.

Microbial xylanases and their industrial applications: a review.

Nanofluids, the fluid suspensions of nanomaterials, have shown many interesting properties, and the distinctive features offer unprecedented potential for many applications. This paper summarizes the recent progress on the study of nanofluids, such as the preparation methods, the evaluation methods for the stability of nanofluids, and the ways to enhance the stability for nanofluids, the stability mechanisms of nanofluids, and presents the broad range of current and future applications in various fields including energy and mechanical and biomedical fields. At last, the paper identifies the opportunities for future research.

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A review on nanofluids: preparation, stability mechanisms, and applications

Phenolics in Food and Nutraceuticals is the first single-source compendium of essential information concerning food phenolics. This unique book reports the classification and nomenclature of phenolics, their occurrence in food and nutraceuticals, chemistry and applications, and nutritional and health effects. In addition, it describes antioxidant activity of phenolics in food and nutraceuticals as well as methods for analysis and quantification. Each chapter concludes with an extensive bibliography for further reading. Food scientists, nutritionists, chemists, biochemists, and health professionals will find this book valuable.

Phenolics in food and nutraceuticals

Two varieties of finger millet (Eleusine coracana)-a tannin-containing red variety, CO13, and nontannin white variety, CO9-processed by treatment with enzymes (cellulase and hemicellulase) and fermentation with starters (from previously fermented finger millet batter), achieved the desirable goals of reduced fermentation time (12 h), increased acidity (2.2 to 2.4%), enhanced in vitro protein digestibility (IVPD) (14 to 26%), and mineral availability compared to 48 h uncontrolled natural fermentation (Usha Antony and Chandra, 1998). Fermentation with starters alone increased titratable acidity (1.02 to 1.88%), IVPD (5. 5 to 22%) and mineral availability, and decreased phytate (23 to 26%) and tannin (10.8 to 40.5%) in the millets. Enzymatic treatment (3 h, 50 degrees C) did not significantly alter the pH, phytate, tannins, IVPD, or HCl-mineral extractability but enhanced fermentative changes. Overall, the changes were marked when the 48 h starter was used and the improvements in nutrient availability was greater in the CO13 variety.

Enzymatic treatment and use of starters for the nutrient enhancement in fermented flour of red and white varieties of finger millet (Eleusine coracana).

The inhibitory effect on Salmonella typhimurium and Escherichia coli of prolonged incubation (0–48h) by finger millet flour fermented for varying time periods (0, 12, 18, 24 and 48h) was tested. S. typhimurium was completely inhibited (100%) in 12h by the 24 and 48h and after 48h by the 12 and 18h fermented samples. Escherichia coli was less inhibited than S. typhimurium, as the 48h fermented sample showed about 50% inhibition in 12h and 100% at 48h. Inhibition of both pathogens was more effective after a longer period of fermentation, suggesting that metabolites produced by the fermenting microbes play a role in this effect. The unfermented millet sample (0 h) also inhibited the pathogens on prolonged incubation for 48 h.

Inhibition of Salmonella typhimurium and Escherichia coli by fermented flour of finger millet (Eleusine coracana)

Influence of finger millet and kodo millet on rat dermal wound healing was assessed by making a 4 cm2 (2 x 2 cm) excision wound on the shaven back of rats under ether anesthesia. Finger millet or kodo millet flour (300 mg) as aqueous paste was applied topically once daily for 16 days. The granulation tissue formed on day 4, 8 and 12 was used to estimate some biochemical parameters like protein, DNA, collagen and lipid peroxides. There was significant increase in protein and collagen contents and decrease in lipid peroxides. Biophysical parameters like rate of contraction and number of days for epithelialization were also studied. Rate of contraction was 88-90% in kodo millet and finger millet treated rats in comparison to 75% in untreated rats. The number of days for complete closure of wounds was lower for finger millet (13 days) and kodo millet (14 days) treated rats in comparison to untreated (16 days) rats. The results implicate a possible therapeutical role for finger millet and kodo millet in accelerating the process of wound healing.

http://nopr.niscair.res.in/bitstream/123456789/23082/1/IJEB%2043%283%29%20254-258.pdf

In vivo effect of whole grain flour of finger millet (Eleusine coracana) and kodo millet (Paspalum scrobiculatum) on rat dermal wound healing

Forty-one cultures degrading and assimilating oxalate were isolated from chicken dung Characterization indicated six different types One of these belonged to the genusAlcaligenes hitherto never reported to degrade oxalate Three groups ofPseudomonas strains differed physiologically from strains already known

Isolation and characterization of some new oxalate-decomposing bacteria.

Aims: To evaluate bacterial community structure and dynamics in triplicate vermicomposts made from the same start-up material, along with certain physico-chemical changes.



Methods and Results:  The physico-chemical parameters (pH, temperature, carbon, nitrogen, soluble substances and cellulose) evolved similarly in the triplicate vermicomposts, indicating a steady function. The 16S bacterial gene abundance remained constant over time. To monitor changes in the bacterial community structure, fingerprinting based on capillary electrophoresis single-strand conformation polymorphism was employed. A rise in bacterial diversity occurred after precomposting and it remained stable during the maturation phase. However, a rapid shift in the structure of the bacterial community in the vermicompost replicates was noted at the beginning that stabilized with the process maturation. Multivariate analyses showed different patterns of bacterial community evolution in each vermicompost that did not correlate with the physico-chemical changes.



Conclusions:  The broad-scale functions remained similar in the triplicates, with stable bacterial abundance and diversity despite fluctuation in the community structure.



Significance and Impact of the Study:  This study has demonstrated that microbial fingerprinting with multivariate analysis can provide significant understanding of community structure and also clearly suggests that an ecosystem’s efficacy could be the outcome of functional redundancy whereby a number of species carry out the same function.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2672.2008.03911.x

T.S. Chandra

Papers

Enzymatic treatment and use of starters for the nutrient enhancement in fermented flour of red and white varieties of finger millet (Eleusine coracana).

Inhibition of Salmonella typhimurium and Escherichia coli by fermented flour of finger millet (Eleusine coracana)

In vivo effect of whole grain flour of finger millet (Eleusine coracana) and kodo millet (Paspalum scrobiculatum) on rat dermal wound healing

Isolation and characterization of some new oxalate-decomposing bacteria.

Structural divergence of bacterial communities from functionally similar laboratory-scale vermicomposts assessed by PCR-CE-SSCP.