The Effect of Pad-Bath pH and Storage Period on the Hydrolysis of DMDHEU

1982 ◽  
Vol 52 (4) ◽  
pp. 269-274 ◽  
Author(s):  
K.R. Beck ◽  
D.M. Pasad
Membranes ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 301
Author(s):  
Xingjia Li ◽  
Zhi Shi ◽  
Xiuli Zhang ◽  
Xiangjian Meng ◽  
Zhiqiang Huang ◽  
...  

The effect of testing temperature and storage period on the polarization fatigue properties of poly (vinylidene fluoride-trifluoroethylene) (P(VDF–TrFE)) ultrathin film devices were investigated. The experimental results show that, even after stored in air for 150 days, the relative remanent polarization (Pr/Pr(0)) of P(VDF–TrFE) of ultrathin films can keep at a relatively high level of 0.80 at 25 °C and 0.70 at 60 °C. To account for this result, a hydrogen fluoride (HF) formation inhibition mechanism was proposed, which correlated the testing temperature and the storage period with the microstructure of P(VDF–TrFE) molecular chain. Moreover, a theoretical model was constructed to describe the polarization fatigue evolution of P(VDF–TrFE) samples.


Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2339
Author(s):  
So-Yul Yun ◽  
Jee-Young Imm

Age gelation is a major quality defect in ultra-high-temperature (UHT) pasteurized milk during extended storage. Changes in plasmin (PL)-induced sedimentation were investigated during storage (23 °C and 37 °C, four weeks) of UHT skim milk treated with PL (2.5, 10, and 15 U/L). The increase in particle size and broadening of the particle size distribution of samples during storage were dependent on the PL concentration, storage period, and storage temperature. Sediment analysis indicated that elevated storage temperature accelerated protein sedimentation. The initial PL concentration was positively correlated with the amount of protein sediment in samples stored at 23 °C for four weeks (r = 0.615; p < 0.01), whereas this correlation was negative in samples stored at 37 °C for the same time (r = −0.358; p < 0.01) due to extensive proteolysis. SDS-PAGE revealed that whey proteins remained soluble over storage at 23 °C for four weeks, but they mostly disappeared from the soluble phase of PL-added samples after two weeks’ storage at 37 °C. Transmission electron micrographs of PL-containing UHT skim milk during storage at different temperatures supported the trend of sediment analysis well. Based on the Fourier transform infrared spectra of UHT skim milk stored at 23 °C for three weeks, PL-induced particle size enlargement was due to protein aggregation and the formation of intermolecular β-sheet structures, which contributed to casein destabilization, leading to sediment formation.


Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 527
Author(s):  
Katarzyna Czyzewska ◽  
Anna Trusek

The current requirements of industrial biocatalysis are related to economically beneficial and environmentally friendly processes. Such a strategy engages low-temperature reactions. The presented approach is essential, especially in food processes, where temperature affects the quality and nutritional value foodstuffs. The subject of the study is the hydrolysis of lactose with the commercial lactase NOLA™ Fit 5500 (NOLA). The complete decomposition of lactose into two monosaccharides gives a sweeter product, recommended for lactose intolerant people and those controlling a product’s caloric content. The hydrolysis reaction was performed at 15 °C, which is related to milk transportation and storage temperature. The enzyme showed activity over the entire range of substrate concentrations (up to 55 g/L lactose). For reusability and easy isolation, the enzyme was encapsulated in a sodium alginate network. Its stability allows carrying out six cycles of the complete hydrolysis of lactose to monosaccharides, lasting from two to four hours. During the study, the kinetic description of native and encapsulated NOLA was conducted. As a result, the model of competitive galactose inhibition and glucose mixed influence (competitive inhibition and activation) was proposed. The capsule size does not influence the reaction rate; thus, the substrate diffusion into capsules can be omitted from the process description. The prepared 4 mm capsules are easy to separate between cycles, e.g., using sieves.


2020 ◽  
Vol 43 (5) ◽  
pp. 126131 ◽  
Author(s):  
Paula de Almeida Carvalho-Estrada ◽  
Juliana Fernandes ◽  
Érica Benjamim da Silva ◽  
Polyana Tizioto ◽  
Solidete de Fátima Paziani ◽  
...  

Author(s):  
Muhammad Akhlaq ◽  
Shinawar Waseem Ali ◽  
Ayesha Murtaza ◽  
Muhammad Arshad Javed ◽  
Aftab Ahmad Khan ◽  
...  

2015 ◽  
Vol 39 (3) ◽  
pp. 276-282
Author(s):  
Hêmina Carla Vilela ◽  
Patrícia de Fátima Pereira Goulart ◽  
Kamila Rezende Dázio de Souza ◽  
Ana Carolina Vilas Boas ◽  
Jane Silva Roda ◽  
...  

The arracacha is an alternative of fresh-cut product; however it can be easily degraded after the processing techniques. The objective of this work was to evaluate the useful life of fresh-cut arracacha submitted to two types of cuts and storage, as well as to evaluate the activity of antioxidant enzymes. The roots were selected, sanitized and submitted to two cut types: cubed and grated. Then they were evaluated at 3 times: 0, 3 and 7 days. The cutting in cubes provided higher quality and lower SOD, CAT and APX activity. However, the grated product presented higher PG activity and lower PPO activity. The microbiological safety and the nutritional value were maintained in both cuts during the whole storage period. The useful life, regarding the physicochemical, nutritional and microbiological aspects, can be established at 7 days under refrigeration for fresh-cut arracacha.


1945 ◽  
Vol 10 (1) ◽  
pp. 16-27 ◽  
Author(s):  
GEORGE FRANKLIN STEWART ◽  
HELEN LOUISE HANSON ◽  
BELLE LOWE ◽  
JOSEPH J. AUSTIN

2020 ◽  
pp. 1-8
Author(s):  
Farhat Anjum ◽  
◽  
Rukhsana Rahman ◽  
Murtaza Gani ◽  
◽  
...  

Four commercially produced dahi samples were stored under 0°C, 10 °C and 20 °C temperatures subjected to microbiological examination, pH, titrable acidity and sensory attributes at various temperatures for a period of seven days. The results indicated an increase in microbial activity parameters and titrable acidity with increase in temperature and storage period. pH of dahi samples decreased with an increase in temperature and storage period indicating increase in acidity. The studies for microbiological studies shows increase in TPC along with the increase in days of storage. Similar case was found in Yeast and mould as well as in Coliform count. The TPC at refrigerated storage was observed as (1.69±0.58)106 to (5.0±0.68)106 while as at 20°C temperature it was observed as (1.5±0.35)106 to (4.5±0.12)10. Similarly the Yeast and mould count at refrigerated storage was observed as (1.0±0.92)106 while as at 20 °C temperature it was observed as ( 1.5±0.36)106 .The different samples of dahi were analysed for various sensorial attributes for their acceptance by using 9 point hedonic scale. The scores obtained with respect to colour, flavour, taste and aroma show good results and overall acceptability. Overall acceptability was also found to decrease significantly (p <.05) with increase in days of storage under refrigerated conditions. The results of the storage studies indicated the significant (p < .05) decrease in pH with the days of storage under different temperature conditions.


2021 ◽  
Vol 845 (1) ◽  
pp. 012094
Author(s):  
I M Novikova ◽  
O M Blinnikova ◽  
L G Eliseeva ◽  
D A Blinnikova

Abstract At present, the preservation of the consumer properties of berry products is an urgent problem. Use of fresh garden strawberries is limited by a short storage period and seasonality. Under optimal storage conditions in a normal atmosphere, the average shelf life of strawberries is from 2 to 9 days depending on the variety. To meet the needs of the population in garden strawberries and meet the physiological needs in a unique complex of biologically active substances, strawberries are subjected to different processing methods. Drying being a type of fruit and berry products processing has the following advantages: a significant increase in the shelf life of products, a decrease in the mass and storage volumes of dried berries, preservation of minerals, carbohydrates, dietary fiber, antioxidants, bioflavonoids and many biologically active compounds in berries. Modern drying technologies allow preserving the content of essential vitamins to its full extent. Comparison of two technologies for drying garden strawberries has established that vitamins and other biologically active substances are well preserved in berries. Berries dried by convective vacuum-impulse method (CVI) are recommended to be used for food enrichment.


Author(s):  
Otávio A. S. Ribeiro ◽  
Kely P. Correa ◽  
Mauricio O. Leite ◽  
Marcio A. Martins ◽  
Jane S. R. Coimbra

The fatty acid's contents of non-conform pooled human milk can be affected by different processing and storage operational conditions. Besides, the knowledge of changes in the human milk fatty acid profile can help indicate its use in a given storage period, according to each newborn's specific need. Thus, in the present work, changes in the fatty acid profiles of three types of human milk (raw; pasteurized at 62.5 °C for 30 min; homogenized at 40 oC for 30 s followed by pasteurization) were studied during storage for six months in a freezer at -18 oC. Large variations were observed in the concentrations of polyunsaturated fatty acids, particularly of docosahexaenoic acid, with a reduction of almost 50% of its total. Palmitic and stearic acid contents also changed according to the conditions of processing and storage. Correlations between the decrease of long fatty acid chains and the increase of medium and short chains were verified.  Thus, we observe that operational conditions of processing and storing change human milk lipid profile, with some nutritional losses.


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