Effects on Gluten of Heating at Different Moisture Contents. II. Changes in Physico-Chemical Properties and Secondary Structure

1994 ◽  
Vol 19 (1) ◽  
pp. 39-47 ◽  
Author(s):  
P.L. Weegels ◽  
A.M.G. de Groot ◽  
J.A. Verhoek ◽  
R.J. Hamer
2021 ◽  
Author(s):  
Rofela Combey ◽  
Prosper Dordunu ◽  
Isaac Kwame Badu ◽  
Peter Quandahor

Abstract Honey is commonly used as a food sweetener in Ghana and it is one of the most important food products with enormous nutritive benefits. In recent times, the increasing concern about sugar related diseases such as diabetes has led to increased consumption of honey in Ghana. This study assessed the physico-chemical properties and microbiological quality of honey collected from supermarkets and apiaries across six major agro-ecological zones of Ghana. In all, 57 honey samples were analyzed for pH, colour, solid sugars and moisture contents, whereas 46 samples were assessed for their microbiological status. The results showed that honey produced in Ghana had significantly wider variations in pH, moisture (p=0.000), solid sugar (0.000) and RI (0.000) within and across the six agro-ecological zones. Similarly, wider variations of these indices occurred between honey harvested from single hives and the admixtures. The results also showed that most of the honey produced in Ghana are characteristically amber in colour, while fewer samples appear black. Honey from the Northern region had the widest variation in colour, ranging from light amber to black. Most of the honeys studied (66.7% of samples) contained solid sugar contents which is either below the CODEX Alimentarius recommendation of 80 %, while 33.3% of the samples contained levels within the recommended ranges. Moreover, the admixture had higher solid sugar contents than single hive honey. About 66% of the honey studied had moisture content above the 20% recommended by USDA and Codex Alimentarius. In addition, the single hive honeys had higher moisture contents than the admixture honeys. The results also revealed that admixtures possess higher RIs than single hive honey. The honey samples assessed in this study were contaminated with bacteria (Bacillus licheniformis, Bacillus subtilis, Citrobacter amalonaticus, Escherichia coli, Micrococcus luteus, Providencia rettgeri, Staphylococcus aureus and Streptococcus faecalis) and fungi genera Aspergillus, Penicillium, and Mucor. Further, 45% of the total samples were above the USDA acceptable limits of microorganisms considered safe for foods and honey. Moreover, significant levels of bacterial and fungal contamination of honey samples; significantly high means of bacterial counts were observed in honey from both admixture and apiaries than fungi. Interestingly, Clostridium botulinum was isolated from a few samples of honey. Only 7% of the total honey samples from Greater Accra, Western, Volta, Eastern and Northern regions contained Clostridium botulinum and this was the first time this organism is being reported in the country. However, contamination levels were below USDA acceptable limits of 1 x 104 CFU per gram for detected samples. Therefore, the honey studied can be considered safe for consumption. This notwithstanding, the study has demonstrated the need for monitoring the quality of honey produced in the country to ensure the safety of consumers.


2014 ◽  
Vol 79 (2) ◽  
pp. 133-150
Author(s):  
Adriana Isvoran ◽  
Dana Craciun ◽  
Alecu Ciorsac ◽  
Nahuel Perrot ◽  
Veronica Beswick ◽  
...  

We performed a bioinformatics study to predict and compare the structural and functional properties of human caveolins: caveolin-1, -2 and -3. The computed local physico-chemical properties, predictions of their secondary structure elements and interacting partners of caveolin-2 and -3 are compared to experimentally proved structural and functional properties of caveolin-1. These data combined with the sequences alignment of the three caveolins, allowed predicting and characterizing the functional domains of caveolin-2 and -3. The hydrophobic regions of these proteins are highly similar in sequences and physicochemical properties and it is in good agreement with their known membrane locations and functions. The most divergent in sequences and properties are the C-terminal regions of caveolins suggesting that they might be responsible for their distinct predicted interactions, with direct consequences on signalling processes.


2007 ◽  
Vol 18-19 ◽  
pp. 165-170 ◽  
Author(s):  
A.V. Ikujenlola ◽  
Benjamin O. Opawale

Freshly harvested cassava(Manihot esculenta) roots were processed into selected products( gari, ‘pupuru’, ‘Lafun’, chips and starch) using unit operations such as peeling, washing, cutting, grating, dewatering(fermentation), smoking, granulated roasting(garifying), milling, packaging). The effects of processing on the yield and phsicochemical properties of the products were investigated. The results showed that peeling accounted for about 22% loss, grating and dewatering operations resulted in over 25% loss. Peeling, dewatering and various drying operations resulted in the detoxification of the products, also moisture contents and pH of the products were reduced. The final yields stood at 22.60%, 31.80%, 40.50%,50.60% and 57.20% for starch, gari, ‘pupuru’, ‘lafun’ and chips respectively. The protein contents of the products ranged between 1.60% and 2.80%. The moisture contents ranged between 8.50% and 10.60% for all the products. The processing operations affected the yield and the physico- chemical properties of the cassava products. Cassava processors should take precautionary measures to reduce wastage thereby increasing the yield and returns for their labour.


Author(s):  
PRESSY P. PRAKASIA

Objective: Computational studies on fish brain acetylcholinesterase were conducted, expanding our views and for a deeper understanding of the activity of the fish acetylcholinesterase enzyme. Methods: Physico-chemical properties of the fish acetylcholinesterase enzyme were studied. Homology model of the acetylcholinesterase enzyme was predicted, validated its quality and active sites were predicted. The amino acid frequency in the active sites was also compared. Similarly, the secondary structure of the sequences was predicted and compared. Phylogenetic analysis was performed by the neighbour joining tree method. Results: Among the selected fish species stability of acetylcholinesterase was found in fish species namely Esox lucius. The negative GRAVY score value of enzyme in all the fish species ensured better interaction and activity in the aqueous phase. It was found that the molecular weight of the acetylcholinesterase enzyme ranged between 9113 and 15991 Da. Iso-electric (pI) of acetylcholinesterase was found to be acidic in nature. GOR IV was used to predict the secondary structure of acetylcholinesterase, which showed that random coil was dominated. Neighbor joining tree of the enzyme showed that fish species named Amphiprion ocellaris as the most divergent species, while the species Oreochromis niloticus is the most primitive one. Conclusion: Acetlycholinesterase enzyme of Esox lucius was found to be the best compared to the other species, which possess a high number of active sites with Ile, Set and Glu rich active sites.


Author(s):  
H. Gross ◽  
H. Moor

Fracturing under ultrahigh vacuum (UHV, p ≤ 10-9 Torr) produces membrane fracture faces devoid of contamination. Such clean surfaces are a prerequisite foe studies of interactions between condensing molecules is possible and surface forces are unequally distributed, the condensate will accumulate at places with high binding forces; crystallites will arise which may be useful a probes for surface sites with specific physico-chemical properties. Specific “decoration” with crystallites can be achieved nby exposing membrane fracture faces to water vopour. A device was developed which enables the production of pure water vapour and the controlled variation of its partial pressure in an UHV freeze-fracture apparatus (Fig.1a). Under vaccum (≤ 10-3 Torr), small container filled with copper-sulfate-pentahydrate is heated with a heating coil, with the temperature controlled by means of a thermocouple. The water of hydration thereby released enters a storage vessel.


1990 ◽  
Vol 63 (03) ◽  
pp. 499-504 ◽  
Author(s):  
A Electricwala ◽  
L Irons ◽  
R Wait ◽  
R J G Carr ◽  
R J Ling ◽  
...  

SummaryPhysico-chemical properties of recombinant desulphatohirudin expressed in yeast (CIBA GEIGY code No. CGP 39393) were reinvestigated. As previously reported for natural hirudin, the recombinant molecule exhibited abnormal behaviour by gel filtration with an apparent molecular weight greater than that based on the primary structure. However, molecular weight estimation by SDS gel electrophoresis, FAB-mass spectrometry and Photon Correlation Spectroscopy were in agreement with the theoretical molecular weight, with little suggestion of dimer or aggregate formation. Circular dichroism studies of the recombinant molecule show similar spectra at different pH values but are markedly different from that reported by Konno et al. (13) for a natural hirudin-variant. Our CD studies indicate the presence of about 60% beta sheet and the absence of alpha helix in the secondary structure of recombinant hirudin, in agreement with the conformation determined by NMR studies (17)


1963 ◽  
Vol 79 (2) ◽  
pp. 263-293 ◽  
Author(s):  
E.M. Savitskii ◽  
V.F. Terekhova ◽  
O.P. Naumkin

1990 ◽  
Vol 39 (442) ◽  
pp. 996-1000 ◽  
Author(s):  
Ayao TAKASAKA ◽  
Hideyuki NEMOTO ◽  
Hirohiko KONO ◽  
Yoshihiro MATSUDA

Sign in / Sign up

Export Citation Format

Share Document