THE QUANTITATIVE ESTIMATION OF FROST INJURY AND RESISTANCE IN BLACK LOCUST, ALFALFA, AND WHEAT TISSUES BY DETERMINATION OF AMINO ACIDS AND OTHER NINHYDRIN-REACTING SUBSTANCES RELEASED AFTER THAWING

1964 ◽  
Vol 42 (6) ◽  
pp. 637-649 ◽  
Author(s):  
D. Siminovitch ◽  
H. Therrien ◽  
F. Gfeller ◽  
B. Rheaume
Keyword(s):  
Amino Acids ◽  
Black Locust ◽  
Quantitative Estimation ◽  
Freezing Temperature ◽  
Freezing Injury ◽  
Tree Bark ◽  
Freezing Process ◽  
Frost Injury ◽  
Ninhydrin Reaction

Amino acids and other soluble α-amino compounds are liberated into a leaching medium from tissues of black locust bark, alfalfa, and wheat that are frozen to temperatures which are injurious to the tissues. The amounts liberated increase with lowering in freezing temperature and are proportional to the loss in vital capacity of the tissue. Insignificant amounts of amino acids are released by leaching of non-frozen tissue while a maximum is reached at freezing temperatures which are completely lethal. The amino acids liberated from frozen and thawed tissues must originate from the destruction of living cells by the freezing process. The determination of the concentration of amino acids in the medium in which the plant tissues are leached after freezing can be used therefore as a quantitative method for the estimation of the injury sustained in the freezing.The use of the ninhydrin reaction for the purpose of this determination is described and its application to the estimation of freezing injury and resistance in a variety of hardy and non-hardy tissues of alfalfa, wheat, and black locust tree bark is shown. The extension of this procedure to the determination of injury produced by toxic and other detrimental agents is indicated.

Frost Injury in Wheat: Ice Formation and Injury in Leaves

1979 ◽  
Vol 6 (4) ◽  
pp. 513 ◽  
Author(s):  
H Marcellos ◽  
MJ Burke
Keyword(s):  
Liquid Water ◽  
Dry Weight ◽  
Freezing Temperature ◽  
Freezing Injury ◽  
Melting Point Depression ◽  
Freezing Process ◽  
Frost Injury ◽  
Temperature Dependance ◽  
Cell Electrolytes ◽  
The Relationship

Freezing of water in leaves of a number of wheat cultivars was studied using pulsed nuclear magnetic resonance (n.m.r.) spectroscopy; these data were coordinated with measurements of the temperature dependance of freezing injury, and used to analyse the freezing process and its effects. The freezing temperature which resulted in 50% loss of cell electrolytes on thawing. T50, varied from -7 to -12.1°C in the material studied. Hardening treatments decreased T50 by 1.8° in the least hardy cultivar, Kite, and 3.3° in the most hardy cultivar, Cheyenne. Despite the contrast in hardiness level, freezing curves determined by n.m.r. were similar, the fraction of water remaining unfrozen, LT/L0, at temperature T having the relationship LT/L0 = ΔTm/T + b, where LT, L0 are the amounts of liquid water per unit dry weight at T and 0�C, respectively, ΔTm is the melting point depression and b the liquid water that does not freeze. The freezing curves were similar because ΔTm varied little among hardy and less hardy samples. At their T50, the least hardy sample of Kite had lost 77.2% of its freezable water to extracellular ice at - 7°C, whereas the corresponding value for the hardy Cheyenne was 86.8% at its T50 of - 12.1°C. Greater hardiness in samples was closely associated with an ability to withstand greater amounts of freeze-induced dehydration, and not with alterations in °Tm.

Influence of Cations on the Ninhydrin Reaction for the Determination of Amino-Acids

Nature ◽  
1953 ◽  
Vol 172 (4377) ◽  
pp. 543-543 ◽  
Author(s):  
HANAN MEYER ◽  
EMANUEL RIKLIS
Keyword(s):  
Amino Acids ◽  
Ninhydrin Reaction

scholarly journals THE STUDY OF THERMAL REVERSIBILITY OF THE FREEZING-DEFROST PROCESS OF BROWNED ONION

2016 ◽  
Vol 4 ◽  
pp. 20-28
Author(s):  
Dmytro Odarchenko ◽  
Oleksander Cherevko ◽  
Andrey Odarchenko ◽  
Nycolay Pogozhikh ◽  
Evgenia Sokolova
Keyword(s):  
Thermal Processing ◽  
Food Product ◽  
Freezing Temperature ◽  
Temperature Curve ◽  
Freezing Process ◽  
Direct Dependence ◽  
Heat Quantity ◽  
Thermal Reversibility

The features and dynamics of the freezing-defrost processes of the studied sample of browned onion were established and studied. At the research it was revealed, that at freezing temperature –20 °С the value of maximal freezing speed does not change. The process of defrost of browned onion was carried out using calorimeter with the reverse connection on temperature and PID-regulator, on the temperature curve of its freezing. It was determined, that the process of defrost of the studied sample needs more heat that is educed at freezing. The modes of stepped defrost that testify to the possibility of thermal reversibility of freezing process were experimentally established. The direct dependence of educed and consumed heat quantity on the mode of thermal processing of studied sample was revealed. The more moisture was eliminated from the food product, the less heat must be consumed for defrost. The analogous dependence is typical also for the freezing process. The received data can be used for determination of the rational modes of freezing and defrost of the browned onion.

A Shortened Method for the Fluorometric Determination of Phenylalanine

1969 ◽  
Vol 15 (1) ◽  
pp. 15-23 ◽  
Author(s):  
John A Ambrose
Keyword(s):  
Amino Acids ◽  
Incubation Temperature ◽  
Fluorometric Method ◽  
Fluorometric Determination ◽  
Reagent Blank ◽  
Ninhydrin Reaction ◽  
Fluorescence Reaction ◽  
Fluorescence Level ◽  
Ruhemann’S Purple

Abstract As a result of a study of the classic ninhydrin reaction with amino acids (which results in the production of Ruhemann’s purple), and the fluorescence reaction occurring between ninhydrin and phenylalanine in the presence of a dipeptide, the initial incubation period in the fluorescence reaction was shortened from 2 hr. to 16 min. This improvement in the fluorometric method for the determination of phenylalanine was accomplished by (1) decreasing the initial incubation pH from 5.8 to 5.0, and (2) increasing the incubation temperature from 60° to 85°. A study of the effect of pH on the fluorescence level in both the acid and alkaline reactions demonstrated the presence of fluorescence pH plateaus. These plateaus indicate that the fluorescence level was relatively unaffected by a change in pH within specified ranges. A study of the specificity led to the discovery that the inclusion of a peptide control was necessary to correct for one type of nonspecific fluorescence. To make this correction, it was necessary to add the reading of the serum blank to that of the reagent blank, and to subtract this total from the sample reading.

scholarly journals A SIMPLE APPARATUS AND PROCEDURE FOR DETERMINATION OF AMINO ACIDS BY THE NINHYDRIN REACTION

1941 ◽  
Vol 137 (2) ◽  
pp. 735-738
Author(s):  
Bert E. Christensen ◽  
Edward S. West ◽  
Keene P. Dimick
Keyword(s):  
Amino Acids ◽  
Simple Apparatus ◽  
Ninhydrin Reaction

The determination of amino-acids colorimetrically by the ninhydrin reaction

The Analyst ◽  
1951 ◽  
Vol 76 (908) ◽  
pp. 623 ◽  
Author(s):  
A. M. Smith ◽  
A. H. Agiza
Keyword(s):  
Amino Acids ◽  
Ninhydrin Reaction
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