Measurement of total free amino acids content in black tea using electronic tongue technology coupled with chemometrics

LWT ◽  
2020 ◽  
Vol 118 ◽  
pp. 108768 ◽  
Author(s):  
Qin Ouyang ◽  
Yongcun Yang ◽  
Jizhong Wu ◽  
Quansheng Chen ◽  
Zhiming Guo ◽  
...  
Keyword(s):  
Amino Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
Electronic Tongue ◽  
Black Tea ◽  
Total Free Amino Acids

scholarly journals Withering timings affect the total free amino acids and mineral contents of tea leaves during black tea manufacturing

2019 ◽  
Vol 12 (8) ◽  
pp. 2411-2417 ◽  
Author(s):  
Saiqa Jabeen ◽  
Sahib Alam ◽  
Maria Saleem ◽  
Waqar Ahmad ◽  
Rukhsana Bibi ◽  
...  
Keyword(s):  
Amino Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
Black Tea ◽  
Tea Leaves ◽  
Mineral Contents ◽  
Total Free Amino Acids

Proteolysis and formation of volatile compounds in cheese manufactured with a bacteriocin-producing adjunct culture

2001 ◽  
Vol 68 (1) ◽  
pp. 117-129 ◽  
Author(s):  
ABDELGHANI OUMER ◽  
PILAR GAYA ◽  
ESTRELLA FERNÁNDEZ-GARCÍA ◽  
RAÚL MARIACA ◽  
SONIA GARDE ◽  
...  
Keyword(s):  
Amino Acids ◽  
Enterococcus Faecalis ◽  
Free Amino Acids ◽  
Free Amino ◽  
Leuconostoc Mesenteroides ◽  
Aminopeptidase Activity ◽  
Hydrophobic Peptides ◽  
Bacteriocin Producer ◽  
Total Free Amino Acids ◽  
Adjunct Culture

Hispánico cheese, a semi-hard Spanish variety, was manufactured from a mixture of pasteurized cows' and ewes' milks (4[ratio ]1) using a commercial mesophilic LD-type starter comprising Lactococcus lactis subsp. cremoris, Lc. lactis subsp. lactis, Lc. lactis subsp. lactis var diacetylactis and Leuconostoc mesenteroides subsp. cremoris. Varying amounts (0–1·0 g/kg) of an Enterococcus faecalis INIA 4 culture in milk were added as a bacteriocin-producing adjunct. Differences in pH between cheeses manufactured with and without the bacteriocin producer did not exceed 0·11 pH units. Starter lactococci lost viability more rapidly in cheeses made with the bacteriocin producer, which reached counts of up to 6×107 cfu/g during ripening. Aminopeptidase activity in 1-d-old cheese made from milk inoculated with 1·0 g bacteriocin-producing culture/kg was twice that in control cheese. Degrees of overall proteolysis and levels of total free amino acids in 45-d-old cheese made with 1·0 g bacteriocin-producing culture/kg were 1·80-fold and 2·17-fold those in control cheese of the same age. Inoculating milk with 1·0 g/kg bacteriocin-producing culture reduced the level of hydrophobic peptides in the resultant cheese, increased the concentrations of 3-methyl-1-butanal, diacetyl and acetoin, and resulted in the highest scores for flavour quality and flavour intensity throughout ripening.

scholarly journals Identification of Umami Taste in Sous-Vide Beef by Chemical Analyses, Equivalent Umami Concentration, and Electronic Tongue System

Foods ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 251 ◽  
Author(s):  
Young-Hwa Hwang ◽  
Ishamri Ismail ◽  
Seon-Tea Joo
Keyword(s):  
Amino Acids ◽  
Principal Component Analysis ◽  
Food Processing ◽  
Free Amino Acids ◽  
Free Amino ◽  
Electronic Tongue ◽  
Principal Component ◽  
Chemical Analyses ◽  
Umami Taste ◽  
Sous Vide

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.

Automated Determination of Free Amino Groups in Serum and Plasma Using 2,4,6-Trinitrobenzene Sulfonate

1969 ◽  
Vol 15 (9) ◽  
pp. 891-901 ◽  
Author(s):  
D W Palmer ◽  
T Peters
Keyword(s):  
Amino Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
Clinical Applications ◽  
Amino Groups ◽  
Automated Method ◽  
Total Free Amino Acids ◽  
Colored Complexes ◽  
Automated Determination

Abstract A simple automated method is described for determining the level of total free amino acids in the blood. The method utilizes the AutoAnalyzer, and is based on the formation of colored complexes by uniting free amino groups with 2,4,6-trinitrobenzene sulfonate (TNBS). Proteins do not interfere because the free amino acids are first separated by dialysis. Characteristics of the reaction and potential clinical applications of the procedure are discussed.

scholarly journals MONITORING THE GROWTH AND QUALITY OF JAPANESE GREEN TEA BY UAV IMAGERY

AGROFOR ◽  
2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Ayako SEKIYAMA ◽  
Kiyohisa SATO ◽  
Sawahiko SHIMADA ◽  
Tomonori FUJIKAWA
Keyword(s):  
Amino Acids ◽  
Green Tea ◽  
Free Amino Acids ◽  
Free Amino ◽  
Vegetation Index ◽  
Chemical Component ◽  
Free Sugars ◽  
Optimal Harvest ◽  
Total Free Amino Acids ◽  
Tea Leaf

The optimal harvest season of Japanese green tea in Japan is judged by individual farmers based on their experiences. To confirm that optimal season, it requires a lot of efforts such as sampling of tea flushes by plucking, chemical component measuring by near-infrared spectroscopic analysis. Thus, an efficient method to determine the optimal season which can cover a wide area at once is considered highly helpful for farmers. This research measured normalized difference vegetation index (NDVI) of tea flushes by a multi-spectrum sensor mounted on an unmanned aerial vehicle. At the same time, chemical component of tea flushes was measured to compare with the result of NDVI. The result showed that the value of NDVI for the optimal harvest season of tea-leaf is 0.6 to 0.7. The result of chemical component measuring showed the increase of total free amino acids and reduction of total free sugars while tea-leaf ripens. Therefore, there was a positive relation between the value of NDVI, and total free amino acids and total free sugars. It indicates a high possibility to predict the optimal harvest season of tea flushes by NDVI.

scholarly journals Using two plant growth promoting bacteria to sustainably reduce the drought-induced loss in Triticum aestivum yield

2020 ◽  
Vol 12 (2) ◽  
pp. 433-446
Author(s):  
El-Anwar OSMAN ◽  
Wedad A. KASIM ◽  
Nabil A. OMAR ◽  
Samar E. SALAMA
Keyword(s):  
Amino Acids ◽  
Drought Stress ◽  
Plant Growth ◽  
Free Amino Acids ◽  
Free Amino ◽  
Azospirillum Brasilense ◽  
Stenotrophomonas Maltophilia ◽  
Plant Growth Promoting ◽  
Total Free Amino Acids ◽  
Growth Promoting

In a greenhouse experiment, the inoculated and uninoculated grains with Azospirillum brasilense NO40 or Stenotrophomonas maltophilia were sown in unsterilized sandy soil and watered normally till the 8th day. Thereafter, the drought stress was initiated by watering pots once every 10 days while the unstressed pots were irrigated normally once every 5 days. Samples of spikes and dry grains were collected after 120 days from sowing. The results indicated that the inoculated-drought-stressed plants maintained significantly higher values of all of the measured yield parameters, where the yielded grains had higher amounts of the direct reducing sugars, sucrose, starch; lower contents of total soluble proteins and the total free amino acids, and altered protein patterns compared to those of the uninoculated-drought-stressed plants. SDS-PAGE of the yielded grains showed that drought led to the appearance of some newly synthesized stress protein bands and disappearance of others. Inoculation with PGPB resulted in the re-appearance of some of the disappearing bands and the synthesis of new others. Meanwhile, wheat inoculation under normal conditions resulted in significantly promoted grain yields with higher contents of carbohydrates, total soluble proteins and total free amino acids than that of the uninoculated control. It has been proved that treating wheat plants with the PEG-tolerant Azospirillum brasilense NO40 or Stenotrophomonas maltophilia that were compatible with the systems into which they were introduced and possess multiple plant growth promoting traits, can be an efficient strategy to enhance wheat growth and productivity, not only under normal conditions, but also under drought stress.

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