Physicochemical properties of three food proteins treated with transglutaminase

Three sources of food proteins were treated with microbial transglutaminase (EC 2.3.2.13) in order to assess changes in the physicochemical properties of reactivity, solubility, emulsification, and free amino groups of the formed polymers. Samples of lactic casein (LC), isolated soy protein (ISP), and hydrolysed animal protein (HAP), were incubated with the enzyme for one or two hours. LC and ISP showed a reduced solubility of 15% and 24% respectively, with HAP showing no alteration on solubility. Amino nitrogen content was 7%, 3% and 2% reduced for HAP, LC and ISP respectively. LC and ISP demonstrated lower emulsifying activity when they were enzymatically treated but the formed emulsions were stable, contrasting with HAP, which exhibited no changes in emulsifying properties.

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Effect of Fermentation Parameters on Natto and Its Thrombolytic Property

Foods ◽

10.3390/foods10112547 ◽

2021 ◽

Vol 10 (11) ◽

pp. 2547

Author(s):

Yun Yang ◽

Guangqun Lan ◽

Xueyi Tian ◽

Laping He ◽

Cuiqin Li ◽

...

Keyword(s):

Bacillus Subtilis ◽

Nitrogen Content ◽

Free Amino ◽

Amino Nitrogen ◽

Fermentation Time ◽

Fermentation Temperature ◽

Sensory Score ◽

Mixed Bacteria ◽

Fermentation Parameters

Natto is a popular food because it contains a variety of active compounds, including nattokinase. Previously, we discovered that fermenting natto with the combination of Bacillus subtilis GUTU09 and Bifidobacterium animalis subsp. lactis BZ25 resulted in a dramatically better sensory and functional quality of natto. The current study further explored the effects of different fermentation parameters on the quality of natto fermented with Bacillus subtilis GUTU09 and Bifidobacterium BZ25, using Plackett–Burman design and response surface methodology. Fermentation temperature, time, and inoculation amount significantly affected the sensory and functional qualities of natto fermented with mixed bacteria. The optimal conditions were obtained as follows: soybean 50 g/250 mL, triangle container, 1% sucrose, Bacillus subtilis GUTU09 to Bifidobacterium BZ25 ratio of 1:1, inoculation 7%, fermentation temperature 35.5 °C, and fermentation time 24 h. Under these conditions, nattokinase activity, free amino nitrogen content, and sensory score were increased compared to those before optimization. They were 144.83 ± 2.66 FU/g, 7.02 ± 0.69 mg/Kg and 82.43 ± 5.40, respectively. The plate thrombolytic area and nattokinase activity both increased significantly as fermentation time was increased, indicating that the natto exhibited strong thrombolytic action. Hence, mixed-bacteria fermentation improves the taste, flavor, nattokinase activity, and thrombolysis of natto. This research set the groundwork for the ultimate manufacturing of natto with high nattokinase activity and free amino nitrogen content, as well as good sensory and thrombolytic properties.

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Studies on soil humic acids II: Observations on the estimation of free amino groups. Reactions of humic acid and lignin preparations with nitrous acid

The Journal of Agricultural Science ◽

10.1017/s0021859600031725 ◽

1957 ◽

Vol 48 (3) ◽

pp. 352-360 ◽

Cited By ~ 29

Author(s):

J. M. Bremner

Keyword(s):

Nitric Acid ◽

Reaction Time ◽

Humic Acid ◽

Acid Hydrolysis ◽

Sodium Hydroxide ◽

Total Nitrogen ◽

Nitrous Acid ◽

Free Amino ◽

Amino Nitrogen ◽

Amino Groups

1. Free amino groups in humic acid preparations isolated from 0·5M-sodium hydroxide and 0·1M-sodium pyrophosphate (pH 7·0) extracts of various soils have been estimated by the nitrous acid method of Van Slyke (1929) and the fluorodinitrobenzene technique of Sanger (1945).2. The results obtained by the Van Slyke method using a reaction time of 15min. indicated that from 12 to 30% of the total nitrogen in the preparations examined was in the form of free amino groups. No free amino groups could be detected by the fluorodinitrobenzene technique.3. It is shown that lignin interferes with the estimation of amino groups by the Van Slyke method, and it is suggested that lignin or ligninderived material may be largely responsible for the high apparent amino-nitrogen values obtained with humic acid preparations by this method.4. The reaction of humic acid with nitrous acid resembles the reaction of lignin with nitrous acid in that it is accompanied by the fixation of nitrogen and the destruction of methoxyl groups. The reaction of lignin with nitrous acid is similar in many respects to its reaction with nitric acid.5. Only about one-third of the nitrogen fixed by lignin in its reaction with nitrous acid is removed by prolonged hydrolysis with 6N-HC1, and most of the nitrogen so released is in the form of ammonia. A small amount of the nitrogen liberated by acid hydrolysis is in the form of hydroxylamine.

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PHYSICOCHEMICAL PROPERTIES OF FORTIFIED CORN CHIPS WITH BROAD BEAN FLOUR, CHICKPEA FLOUR OR ISOLATED SOY PROTEIN

Journal of Food Quality ◽

10.1111/j.1745-4557.2012.00440.x ◽

2012 ◽

Vol 35 (3) ◽

pp. 200-206 ◽

Cited By ~ 10

Author(s):

TAHA M. RABABAH ◽

SUSAN BREWER ◽

WADE YANG ◽

MAJDI AL-MAHASNEH ◽

MUHAMMAD AL-U'DATT ◽

...

Keyword(s):

Physicochemical Properties ◽

Soy Protein ◽

Broad Bean ◽

Chickpea Flour ◽

Bean Flour ◽

Isolated Soy Protein

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Simple Tests for the Demonstration of the Low Free Amino Nitrogen Content in Psoriatic Scales1

Journal of Investigative Dermatology ◽

10.1038/jid.1957.96 ◽

1957 ◽

Vol 29 (4) ◽

pp. 247-249 ◽

Cited By ~ 11

Author(s):

Peter Flesch ◽

Elizabeth C Jackson Esoda

Keyword(s):

Nitrogen Content ◽

Free Amino ◽

Amino Nitrogen

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System for the evaluation of malting quality of wheat varieties

KVASNY PRUMYSL ◽

10.18832/kp2020.66.232 ◽

2020 ◽

Vol 66 (1) ◽

Cited By ~ 1

Author(s):

Vratislav PSOTA ◽

Markéta Musilová

Keyword(s):

Nitrogen Content ◽

Free Amino ◽

Amino Nitrogen ◽

Malting Quality ◽

Soluble Nitrogen ◽

Regression Equations ◽

Wheat Varieties ◽

Nitrogenous Substances ◽

A Site

A new system for the calculation of malting quality of wheat varieties was designed. The malting parameters affected by a variety more than by a year or a site were used in the system. These parameters include wort viscosity, soluble nitrogen content, free amino nitrogen content, diastatic power, final attenuation of wort, and extract of malt. The system was used to assess the malting quality in 38 wheat varieties. The point value of each parameter was calculated using the regression equations, and the total value of the malting quality of wheat was determined by the modified “superiority measure” method. The results of the assessment of the wheat malting quality showed considerable differences between the varieties. Several varieties exhibited a more pronounced tendency to accumulate nitrogenous substances in grain. Some varieties, even with a slightly higher content of nitrogenous substances, provided above average malt quality. The set included the varieties that exhibited the optimal content of nitrogenous substances in grain, yet they did not give malt of good quality. Spring wheat varieties Alondra, Anabel, and Seance achieved significantly above average malting quality. Dagmar, Evina, Sultan, Rumor, Sailor, and Brokat exhibited slightly above average malting quality. The proposed system for monitoring malting quality of wheat varieties can help find the varieties suitable for the production of quality wheat malt.

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COMPARATIVE STUDIES OF THE POTENTIATION OF CORTICOTROPHIN ACTIVITY BY SEVERAL INACTIVE DERIVATIVES

Acta Endocrinologica ◽

10.1530/acta.0.0420209 ◽

1963 ◽

Vol 42 (2) ◽

pp. 209-213 ◽

Cited By ~ 4

Author(s):

Arthur I. Cohen ◽

Edward H. Frieden

Keyword(s):

Biological Activity ◽

Comparative Studies ◽

Free Amino ◽

Hormonal Activity ◽

Amino Groups

ABSTRACT A number of corticotrophin analogues have been prepared, some of which potentiate the biological activity of the untreated hormone in vitro. The free amino groups of corticotrophin appear to be essential not only for hormonal activity, but also for the interaction of the analogues with the tissue corticotrophin inactivating system which is assumed to account for the potentiating effect.

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