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Food habits of Muglids from water around Port Harcourt Texto completo
2009
Allison, M.E. | Davids, C.B.D. | Kingdom, T.
The food habits of four species of Muglidae, consisting of Liza grandisquamus, L falcipinus, Mugil curema and , were investigated using the frequency of occurrence and numerical methods of analysis. Also, Relative Gut Length (RGL) of fish specimen measured was calculated from fish gut length. Generally, the food consisted mainly diatoms, blue - green & green algae and detritus. Other food items included annelid, crustacea, nematode, insect parts, dinoflagellates and unidentified organisms. M. curema had the least Species Richness Index (2.827) while L grandisquamus had the highest (4.088). The Shanon - Wiener Diversity Index ranged 0.91 in M. curema to 1.03 in L. falcipinus, while Shanon's Index (HI]) ranged from 2.095 (M. curema) to 2.372(L falcipinus).The male M. bananesis had the least mean RGL of 2.48 ~c 0.17 while female L. falcipinus and L grandisquamus had the highest mean RLG of 3.31 ~c 0.13. The food items observed and the RGL suggest that the muglids studied were herbivorous or omnivorous. | Includes:- 18 refs.
Mostrar más [+] Menos [-]Water activity and chemical composition of some food emulsions
1992
Gomez, R. | Fernandez-Salguero, J.
The water activity, pH and other compositional parameters such as the moisture, fat and NaCl contents of various food emulsions were determined: butters, margarine (W/0) and mayonnaises (O/W). Water activity was determined by a gravimetric method (PEC procedure) and an instrumental method (dew-point hygrometer). The mean a(w) values obtained for the samples assayed were 0.904 +/- 0.050 (butters), 0.914 +/- 0.028 (margarines) and 0.947 +/- 0.013 (mayonnaises). The a(w) of the butter and margarine samples could be predicted with an error less than 0.02 units from the NaCl content of their aqueous phase (m) by using the following simple linear regression equation: a(w) = 0.954 - 0.036m. This equation could not be used to predict the a(w) of the mayonnaises, which, however, were obtained by using the Chen equation for mixtures of solutes.
Mostrar más [+] Menos [-]Effects of water on the physical properties of food Texto completo
2019
Kawai, K. (Hiroshima University, Higashi-Hiroshima, Hiroshima (Japan). Graduate School of Integrated Sciences for Life)
Solid food products are typically in an amorphous state, and their physical properties change dramatically at the glass to rubber transition temperature (Tsub(g)). Tsub(g) decreases with increasing water content because of water plasticizing effects. When Tsub(g) becomes lower than the ambient temperature, a glass to rubber transition occurs at the ambient temperature. The water content at Tsub(g) = 25℃ is usually described as the critical water content (w sub(c)). In this review, the effect of glass to rubber transition on the texture of cookies, the caking of mango powder and the compressibility of soup powder is explained. Tsub(g) of the food samples was evaluated by differential scanning calorimetry or thermal rheological analysis. Wsub(c) was determined from the relationship between Tsub(g) and water content. Fracture properties of the cookie samples changed from brittle to ductile at Wsub(c). Caking of mango powder occurred at water contents above Wsub(c). Hardness of soup powder compressed at temperatures above Tsub(g) was much higher than when compressed at temperatures below Tsub(g).
Mostrar más [+] Menos [-]Chlorogenic acid-water complexes in chlorogenic acid containing food products Texto completo
2022
Holowinski, Piotr | Dawidowicz, Andrzej L. | Typek, Rafal
Chlorogenic acid (CQA), the ester of caffeic acid with quinic acid, has been one of the most studied polyphenols due to its potential biological activity and usefulness in pharmaceutical treatment. We found that in an aqueous solution of each chlorogenic acid isomer, 3-, 4- and 5-CQA, its two complexes with water are formed. In the RP chromatographic system, these CQA-water derivatives differ in retention data from that of their precursors and do not decompose, which indicates their considerable stability. The formation of CQA-water complexes has not been reported yet. Comprehensive NMR research of CQA-water derivatives complexes shows that their significant stability results from the formation of hydrogen bonds between water and CQA isomer – e.g., between water and OH3, OH4 and ester groups of CQA molecule in the case of 5-CQA-water derivative. The existence of CQA-water derivatives in CQA containing food products was in the paper shown. It should be noted that the stable CQA-water complexes may exhibit a different biological activity than CQA. This issue requires separate biomedical research.
Mostrar más [+] Menos [-]Partition of selected food preservatives in fish oil-water systems Texto completo
2010
Cheng, Hongyuan | Friis, Alan | Leth, Torben
The partition coefficients (K ow) of benzoic acid and sorbic acid in systems of fish oil (sand eel)-water, fish oil-buffer solution, rape oil-water and olive oil-water were experimentally determined in a temperature range from 5 to 43°C and pH from 4.5 to 6.5°C. The dimerization of benzoic acid in fish oil-water system was observed at 25°C. Two modifications have been made to the Nordic Food Analysis Standard for the determination of sorbic acid by HPLC. The experimental results show that the K ow of benzoic acid and sorbic acid in fish oil-buffer system is ca. 100 times lower than that in fish oil-water system. The K ow values of benzoic acid and sorbic acid in fish oil and water system decrease with increasing system pH values. The partition coefficients of plant origin and fish origin oils are in the same order of magnitude even though their molecular structures are very different.
Mostrar más [+] Menos [-]Water as the determinant of food engineering properties. A review
2004
Lewicki, P.P.
Water affects safety, stability, quality and physical properties of food. The influence of water on physical properties of food is dependent on the state of water in food. The state, expressed as water activity, is briefly discussed in the paper. Further, the influence of water on such physical properties as rheological, thermal, mass transfer, electrical, optical and acoustic is presented in details.
Mostrar más [+] Menos [-]Microbial Growth in Dry Grain Food (Sunsik) Beverages Prepared with Water, Milk, Soymilk, or Honey-Water Texto completo
2010
Jung, Jin-Ho | Lee, Sun Young
This study was conducted to investigate the growth of microorganisms, including pathogenic bacteria such as Cronobacter sakazakii and Bacillus cereus, in Sunsik beverages made of water, milk, soymilk, or honey-water during storage at room temperature. Prepared Sunsik beverages were stored at room temperature and the growth of total aerobic counts, Escherichia coli/coliforms, and yeast and mold were measured. Also, samples inoculated with a cocktail of C. sakazakii or B. cereus spores were stored at room temperature and their growths were determined during storage. Populations of total aerobic counts and coliforms significantly increased with increasing storage time at room temperature, which resulted in higher than 8 log and 7 log after 24 h in all samples except for the honey-water sample, respectively. Levels of total aerobic counts and coliforms were significantly lower in the honey-water sample than in the other samples after 6 and 9 h of storage, respectively. Initial populations of C. sakazakii and B. cereus ranged from 0 to 1 log CFU/mL, respectively, and these populations significantly increased with increasing storage time at room temperature. Therefore, populations of C. sakazakii and B. cereus were approximately 7 to 8 log CFU/mL after 24 h of storage. However, after 12 and 9 h of storage, there were significant differences in levels of C. sakazakii and B. cereus between the honey-water sample and the other samples, respectively. Based on these results, the addition of honey can inhibit microbial growth in Sunsik beverages; however, the best way to avoid pathogen infection would be to consume Sunsik beverages as soon as possible after preparation.
Mostrar más [+] Menos [-]The Volta River Basin: water for food, economic growth and environment
2016
Williams, Timothy O. | Mul, Marloes L. | Biney, C.A. | Smakhtin, Vladimir U.
The Volta River Basin: water for food, economic growth and environment
2016
Williams, Timothy O. | Mul, Marloes L. | Biney, C. A. | Smakhtin, Vladimir
Beryllium in food and drinking water--a summary of available knowledge Texto completo
2000
Vaessen, H.A.M.G. | Szteke, B.
In an overall evaluation of the situation published by IARC in 1993, beryllium and beryllium compounds are identified as carcinogens to humans. This prompted the initiation of this study on beryllium which reviews the situation up to 1998 on the aspects: properties and applications, toxicity, analytical procedures for food and drinking water, reference materials, occurrence in food and drinking water and estimates of daily dietary exposure. Special emphasis is put on analytical aspects and levels of beryllium in food and drinking water.
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