scholarly journals Effect of salinity and pH on growth, phycoerythrin, and non-volatile umami taste active compound concentration of Rhodomonas salina using a D-optimal design approach

Author(s):  
Christos Latsos ◽  
Georgios Bakratsas ◽  
Tanja Moerdijk ◽  
Jasper van Houcke ◽  
Klaas R. Timmermans

AbstractThe cryptophyte Rhodomonas salina is widely used in aquaculture due to its high nutritional profile. This study aims to investigate the effect of salinity and pH on the growth, phycoerythrin concentrations, and concentrations of non-volatile umami taste active compounds of R. salina, using a design of experiment approach. Rhodomonas salina was cultivated in a flat-panel photobioreactor in turbidostat mode in a range of salinity (20–40 ‰) and pH (6.5–8.5). The strain was able to grow steadily under all conditions, but the optimal productivity of 1.17 g dry weight L−1 day−1 was observed in salinity 30 ‰ and pH 7.5. The phycoerythrin concentration was inversely related to productivity, presenting higher values in conditions that were not optimal for the growth of R. salina, 7% of dry weight at salinity 40 ‰, and pH 8.5. The identification of the umami taste of R. salina was based on the synergistic effect of umami compounds 5′-nucleotides (adenosine 5′-monophosphate, guanosine 5′-monophosphate, inosine 5′-monophosphate) and free amino acids (glutamic and aspartic acids), using the equivalent umami concentration (EUC). The results indicated that an increase in pH induces the accumulation of 5′-nucleotides, resulting in an EUC of 234 mg MSG g−1 at a salinity of 40 and pH 8.5. The EUC values that were observed in R. salina were higher compared to other aquatic animals, a fact that makes R. salina promising for further research and application in the food and feed sectors.

2021 ◽  
pp. 131352
Author(s):  
Tanja C.W. Moerdijk-Poortvliet ◽  
Dylan L.C. de Jong ◽  
Roy Fremouw ◽  
Sandra de Reu ◽  
Jose M. de Winter ◽  
...  

Foods ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 251 ◽  
Author(s):  
Young-Hwa Hwang ◽  
Ishamri Ismail ◽  
Seon-Tea Joo

Behaviour of umami compounds that are associated with non-volatile compounds on slow cooking regimes remains less explored. This study aims to assess the ability of the electronic tongue system on the umami taste from sous-vide beef semitendinosus. The identification was based on the taste-enhancing synergism between umami compounds 5’-nucleotides (IMP, GMP, AMP, inosine, and hypoxanthine) and free amino acids (glutamic and aspartic acid) using the estimation of equivalent umami concentration (EUC) and electronic tongue system. Sous-vide cooked at 60 and 70 °C for 6 and 12 h and cooked using the conventional method at 70 °C for 30 min (as control) were compared. The temperature had a significant effect on 5’-nucleotides, but aspartic and glutamic acid were not influenced by any treatments applied. Sous-vide cooked at 60 °C tended to have higher inosine and hypoxanthine. Meanwhile, desirable 5’-nucleotides IMP, AMP, and GMP were more intensified at the temperature of 70 °C. The principal component analysis predicted a good correlation between EUC and the electronic tongue, with sous-vide at 70 °C for 12 h presenting the most umami. Therefore, the electronic tongue system is a useful tool in food processing, particularly in determining complex sensory properties such as umami, which cannot be evaluated objectively.


1967 ◽  
Vol 45 (4) ◽  
pp. 459-477 ◽  
Author(s):  
Vittorio Raggi

Some of the changes induced by Taphrina deformans on metabolism (particularly the nitrogen metabolism) of peach leaves were studied. Observations were as follows. (1) Dry weight diminishes in the infected tissues, especially at the end of the cycle, whereas it remains almost unchanged in the non-infected tissues of the diseased plant. (2) Initially, the amount of total nitrogen, per gram of dry substance is clearly greater in the infected tissues than in the control, then it becomes lower during the differentiation of the asci, especially at the stage of full sporulation. Similar variations occur also, in a more attenuated form, in the non-infected tissues. (3) A considerable increase of the glycolytic activity is observed in the infected tissue especially during the period preceding the differentiation of the asci, and an increase of respiration, even though much more restricted, is observed also in the next period. In non-invaded tissues, an increase of glycolysis is noted along with a diminution of respiration. (4) The non-infected leaves weigh more than those of the control until the differentiation of the asci; after it, they have a clear drop up to the maturity of the asci, and a further revival at the end of the disease. (5) In the infected tissues, the content of free amino acids is always higher than in the control (with a maximum after sporulation), whereas in the non-infected ones it is generally lower. (6) The more important alterations in the pool of the free amino acids in invaded tissues consist in a scarcity, in percentage of the total, of alanine and glutamic acid, especially at the end of the disease, whereas proline, ornithine, glycine, and others increase, especially during the incubation period. In particular the glutamine–asparagines– threonine group reaches the highest value when sporulation has occurred. In the non-invaded tissues, the changes are more restricted. (7) The content of protein amino acids in infected tissues is generally lower than in the control, especially in the last phases of infection whereas in the non-invaded parts it is generally higher, except in differentiation of the asci. (8) In the infected tissue, the alterations of the quantitative relationships between the single protein amino acids (in percentage of the total) are not very great, but some diminutions and increases are recorded (diminution of alanine, glycine, leucine, etc.; increase of lysine, histidine, etc.); in the non-infected tissues, no noteworthy alterations were observed.


Author(s):  
J. C. A. Craik ◽  
S. M. Harvey

Pelagic eggs and demersal eggs of teleosts both have osmotic concentrations similar to that of the maternal body fluids, less than half that of sea water. Pelagic eggs are buoyant because they contain such large quantities of this dilute aqueous fluid. While the demersal eggs of teleosts usually have a water content of 60–70%, the buoyant pelagic eggs of marine teleosts such as whiting, Norway pout, saithe, cod, haddock, turbot, dab, plaice, witch, long rough dab, halibut and sole typically have a very high water content (ca. 92 %) and a lipid content of 10–17% of egg dry weight. About 90% of the buoyancy of such eggs in sea water is caused by their high aqueous content, only about 10% being caused by lipid. The buoyant eggs of grenadier and ling have large oil globules and higher lipid contents, 27 and 35 % of dry weight respectively. Nevertheless, most of their buoyancy is provided by their high aqueous contents (89 and 81 % water). The high water content of pelagic eggs is brought about by a massive influx of water into the oocytes during meiotic maturation (ripening) after vitellogenesis but before ovulation. In cod and plaice, ripening is accompanied by a four- to five-fold increase in both water content and free amino-acids, and by a large influx of both potassium and sodium. In cod, free amino-acids contribute much more than these inorganic ions to the water influx and to the total osmotic concentration of the mature egg, but in plaice the relative contribution of inorganic ions approaches that of the free amino-acids.


2021 ◽  
pp. 1-10
Author(s):  
A.K. Mugova ◽  
C.J. Zvidzai ◽  
R. Musundire

Armoured crickets are an important food source in some parts of Zimbabwe. These insects are abundant in some regions but however, they are under utilised and not much is known about their nutritional value. The aim of this study was to determine the nutritional profile of the armoured cricket (Acanthoplus discoidalis). Armoured crickets were collected from a structured sampling framework in Mbire district Mashonaland Central province of Zimbabwe. Removal of the head and thorax, degutting and boiling were done. A proximate analysis was carried out followed by mineral, amino acid and fatty acid profiling of the prepared insects. Analyses were done on a dry basis. A. discoidalis contained 69.2% protein, 16.8% fat, 8.6% ash, 1.2% carbohydrate, 4.2% chitin and 454.3 Kcal/100 g energy. A 100 g dry weight quantity of insect contains 11.48 mg iron which is enough to meet the required daily intake of 10.0-20 mg/day for an adult. The zinc (4.37 mg/100 g dry weight) and phosphorus (491.4 mg/100 g dry weight) content in A. discoidalis almost meets the reference nutrient intake for adults. Essential amino acids, leucine (60.7 mg/g protein) had the highest concentration followed by phenylalanine+tyrosine (59.3 mg/g protein), valine (48.4 mg/g protein), lysine (46.7 mg/g protein), threonine (37.4 mg/g protein), isoleucine (26.4 mg/g protein), methionine+cysteine (20.9 mg/g protein) and histidine (16.5 mg/g protein) the least concentration. In total, 9 saturated fatty acids were determined of which stearic acid and palmitic acid had the highest concentrations of 2,034.5 mg/100 g and 2,005.3 mg/100 g respectively. Four mono unsaturated fatty acids were determined of which oleic acid and palmitoleic acid had the highest concentrations of 361.4 mg/100 g and 305.2 mg/100 g respectively. Four poly-unsaturated fatty acids were determined of which eicosapentaenoic and α-linolenic acid had the highest concentrations of 1,598.0 mg/100 g and 185.6 mg/100 g respectively. A. discoidalis is good source of protein, the minerals iron, zinc and phosphorus, some essential amino acids and poly-unsaturated fatty acids.


1995 ◽  
Vol 16 (1) ◽  
pp. 73-81
Author(s):  
M. Tertuliano ◽  
B. Le Rü

AbstractThe effect of a 2-month infestation by the cassava mealybug (Phenacoccus manihoti Mat. Ferr.) on the metabolism of nitrogen (amino acids) and carbon (carbohydrates), leaf area and total dry weight of five cassava varieties (Manihot esculenta Crantz), faux-caoutchouc (a hybrid of M. esculenta and M. glaziovii Muell, Arg.), poinsettia (Euphorbia pulcherrima Wild) and talinum (Talinum triangulare Jack) was studied. Free amino acid and free sugar contents as well as relative free amino acid composition in the leaf extracts, although found to be very different from one plant to another, were not significantly modified by P. manihoti infestation, except for the total amino acid contents of the cassava variety 30M7. Variations in one particular amino acid induced by mealybug infestation were not linked to the antibiotic resistance of these plants. Infestation by the cassava mealybug did not modify the total dry weight but reduced the total leaf area although this reduction was only significant in cassava varieties 59M2, 30M7 and M'pembe, and in faux-caoutchouc. Within the genus Manihot, the reduction in leaf area was strongly correlated (r= -0.878, P≤0.05) to the degree of antibiotic resistance and was coupled to an increase in the ratio of sugars to amino acids, suggesting a similarity between the effects of water stress and those of mealybug infestation.


1990 ◽  
Vol 36 (2) ◽  
pp. 378-381 ◽  
Author(s):  
G Ollenschläger ◽  
K Langer ◽  
H M Steffen ◽  
M Schrappe-Bächer ◽  
H Schmitt ◽  
...  

Abstract We report for the first time the concentrations of free amino acids in human intestinal biopsies obtained by routinely performed endoscopy. We studied 15 medical patients with no changes of the mucosa and six HIV-infected persons with duodenitis. The mean (and SD) sum of all amino acids, taurine excepted, was 61.9 (5.4) mmol/kg dry weight in duodenal biopsies of HIV-negative subjects (n = 11) and 82.9 (0.6) mmol/kg in colonic specimens: 50% (44%) of the total (minus taurine) consisted of aspartate and glutamate and 14% (12%), of the essential amino acids. The relative amino acid pattern in duodenum and colon differed completely from that for muscle: aspartate was fourfold higher; glutamate, phenylalanine, glycine, valine, leucine, and isoleucine were about twofold higher. In contrast, glutamine amounted only to 4% (duodenum) to 14% (colon) of muscle glutamine. In duodenal biopsies of the HIV-infected persons, we found significantly (P less than 0.01, except glutamine: P less than 0.025) increased concentrations of glutamate (24.1 vs 17 mmol/kg dry weight), ornithine (1.4 vs 0.4), valine (2.2 vs 1.7), and glutamine.


Plants ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 588
Author(s):  
Hira Yaqoob ◽  
Nudrat A. Akram ◽  
Samrah Iftikhar ◽  
Muhammad Ashraf ◽  
Noman Khalid ◽  
...  

In the current study, the effects of exogenously applied proline (25 and 50 mM) and low-temperature treatment were examined on the physiochemical parameters in the plants of two cultivars (V1 and V2) of quinoa (Chenopodium quinoa Willd.). The seeds were also exposed to chilling stress at 4 °C before sowing. Plants raised from the seeds treated with low temperature showed reduced plant growth and contents of chlorophyll and carotenoids, but they had significantly increased contents of malondialdehyde, proline, ascorbic acid, total free amino acids, total soluble sugars, and total phenolics, as well as the activity of the peroxidase (POD) enzyme. Cold stress applied to seeds remained almost ineffective in terms of bringing about changes in plant root, hydrogen peroxide, glycine betaine and activities of superoxide dismutase (SOD), and catalase (CAT) enzymes. The exogenous application of proline significantly increased plant growth, the contents of chlorophyll, carotenoids, proline, ascorbic acid, total free amino acids, phenolics, and total soluble sugars, as well as the activities of SOD, POD, and CAT, but it decreased malondialdehyde content. Overall, foliar application of proline was better than the seed treatment in improving root dry weight, root length, chlorophyll a, carotenoids, glycine betaine, ascorbic acid and superoxide dismutase activity, whereas seed pre-treatment with proline was effective in improving shoot dry weight, shoot length, hydrogen peroxide, malondialdehyde, and peroxidase activity in both quinoa cultivars.


2007 ◽  
Vol 132 (1) ◽  
pp. 3-13 ◽  
Author(s):  
Timothy L. Righetti ◽  
David R. Sandrock ◽  
Bernadine Strik ◽  
Carmo Vasconcelos ◽  
Yerko Moreno ◽  
...  

It is not appropriate to compare ratio-based expressions for different cultivars or treatments if a plot of the denominator versus the numerator of a ratio-based expression has a nonzero y-intercept and the values for either the denominators or numerators differ with cultivars or treatments. Whenever nonzero y-intercepts are encountered, the value for a ratio-based expression will be dependent on both the denominator and numerator. The “ratio problem” is demonstrated with shoot N concentration in blueberries (Vaccinium corymbosum L.) and amino acid accumulation in almonds [Prunis dulcis (Mill.) D.A. Webb]. Data were collected from the first and second growth flush of blueberry shoots on plants that were at two in-row spacings and two rates of N fertilizer. Free amino acid:total amino acid ratios were measured in dormant almond trees fertilized at different rates with and without foliar N supplements. Functions describing the relationship between dry weight and total N content in blueberry tissues have positive y-intercepts for both N fertilizer application rates. Functions describing the relationship between total amino acids and free amino acids in almond trees have a negative y-intercept. Differences attributable to fertilization rate in blueberries probably were the result of differences in N uptake and N utilization, but the effects of spacing and growth flush are indirect and can be accounted for by differences in dry weight. Likewise, effects of fertilization rate and foliar N supplement in almonds are indirect and can be accounted for by differences in the total amino acids in dormant trees. With regression one can determine if the relationship between the denominator and numerator differs for the groups or treatments being studied. When an analysis of covariance is used to account for differences in the denominators of ratio-based expressions, results are consistent with the regression analysis. When a conclusion is based on statistical differences of a ratio-based expression, it is the researcher's responsibility to determine whether these effects are direct or indirect.


1980 ◽  
Vol 7 (1) ◽  
pp. 32-37 ◽  
Author(s):  
S. M. M. Basha ◽  
J. P. Cherry ◽  
C. T. Young

Abstract Maturing seeds of six peanut cultivars (Arachis hypogaea L.) varying in protein content at maturity showed differences in rate of change of dry weight, crude protein, and free and total amino acids. Seeds of the high-protein cultivars increased in dry weight and deposited protein at a more rapid rate between immature and low intermediate stages of maturation than did those of the low- and intermediate-protein cultivars. Free amino acid content in seeds classified as low-intermediate maturity from all cultivars was significantly less than was that of those at the immature stage. The greatest change was in seed of the high-protein group. The rate of change of content of selected free amino acids among seed was different for the three groups of cultivars. Similar observations were noted as the content of select total amino acids increased in maturing seeds. Variations in quantities of free amino acids in immature seeds and differences in the rate at which they are incorporated into proteins of seeds from various cultivars suggest that there is genetic variability in the mechanism for synthesis of selected proteins. These differences also indicate the potential for the development of peanut cultivars having seed with nutritionally desirable protein.


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