Study of acid milk coagulation by an optical method using light reflection

1991 ◽  
Vol 58 (1) ◽  
pp. 75-84 ◽  
Author(s):  
Sylvie Banon ◽  
Joël Hardy
Keyword(s):  
Dynamic Viscosity ◽  
Network Formation ◽  
Ph Value ◽  
Great Influence ◽  
Skim Milk ◽  
Lag Phase ◽  
Light Reflection ◽  
Two Factors ◽  
Capillary Viscosimetry ◽  
Milk Coagulation

SummaryA turbidimetric method, based on light reflection, was used to study acid coagulation of reconstituted skim milk at low temperature. Capillary viscosimetry, gelograph and laser granulometer techniques were also employed. Acidification of milk was produced by hydrolysis of glucono-δ-lactone. The general shape of the turbidimetric signal as a function of pH or time can be divided into three stages: a lag phase followed by a significant decrease and then a final rise. Two factors have a great influence on the development of milk turbidity, pH and temperature. Dynamic viscosity measurements can be related to the turbidimetric signal while laser granulometrie measurements cannot be correlated with changes in turbidity: the micelle size distribution remains constant until the first signs of gelation. As previous work showed, dynamic viscosity diminishes with acidification until a particular pH is reached (pH 5·9 at 15°C and pH 5·75 at 20°C). We have related this latter period to the turbidimetric lag phase. As milk turbidity became lower than its initial value (pH 5·75 at 15°C and pH 5·55 at 20°C), dynamic viscosity increased significantly. The release of material from micelles (β-casein and Ca) could explain this phenomenon. In the same way, further increase of turbidity at a particular pH value (pH 5·3 at both 15 and 20°C) coulcl be partly due to the reincorporation of soluble casein monomers in the micelle framework. As the onset of gelation was approached, turbidity still increased as a result of gel network formation.

scholarly journals Sugarcane juice fermentation for making probiotic beverage with variations of type and concentration of inoculum

1970 ◽  
Vol 5 (1) ◽  
pp. 1-7
Author(s):  
DWI KRISTANTI ◽  
RATNA SETYANINGSIH ◽  
ARI SUSILOWATI
Keyword(s):  
Ph Value ◽  
Sugar Content ◽  
Skim Milk ◽  
Sugarcane Juice ◽  
Bacterial Cells ◽  
Significance Level ◽  
Organoleptic Test ◽  
Randomized Design ◽  
Two Factors ◽  
The Media

Kristanti D, Setyaningsih R, Susilowati A. 2006. Sugarcane juice fermentation for making probiotic beverage with variations of type and concentration of inoculum. Biofarmasi 5: 1-7. The exact type and concentration of inoculum in the manufacture of probiotic beverage is expected to produce a probiotic beverage that can meet the standard. The aims of this research were to determine the type of inoculum, the concentration of inoculum, and the combination of type and concentration of inoculum that meet the standard that reviewed from the number of viable bacterial cells, reduction sugar content, acid total, the value of pH and organoleptic test. The research was conducted by using a factorial completely randomized design consisted of two factors: (i) the type of inoculum consisted of three levels, namely Lactobacillus casei, L. acidophilus and L. plantarum; (ii) the concentration of inoculum consisted of three levels, i.e. 1%, 2% and 3%. The experiment was conducted with three replications. The media of fermentation including sugarcane juice, skim milk 10% and gelatin 0.3% fermented with each inoculum for 96 hours. The parameters measured included the number of viable bacterial cells, acid total, pH value, reduction sugar content and organoleptic test. Data obtained were analyzed by Analysis of Variance (ANOVA) and continued with DMRT test at the significance level of 5%. The organoleptic test was analyzed by using a hedonic method. The results of research showed that all types and the concentration of inoculum tested could be used in the fermentation of sugarcane juice for making probiotic beverage. The number of viable bacterial cells and the pH value met the standards of probiotic beverage in all treatments. The total of acid met the standards of probiotic beverage, exept in the treatment of L. casei dan L. plantarum 1%. The result of organoleptic test showed that the preference of panelist in the scale of dislike to rather likes.

scholarly journals Artificial rearing of pigs

1980 ◽  
Vol 44 (2) ◽  
pp. 161-170 ◽  
Author(s):  
M. J. Newport ◽  
H. D. Keal
Keyword(s):  
Nucleic Acids ◽  
Crude Protein ◽  
Ph Value ◽  
Skim Milk ◽  
Live Weight ◽  
Single Cell Protein ◽  
Soya Bean ◽  
Cell Protein ◽  
Milk Diet ◽  
Protein Nitrogen

1. Spray-dried diets were prepared containing (g/kg): dried skim-milk 665, dried whey 65, soya-bean oil 270 (diet U); or single-cell protein (Pruteen; SCP) 308, dried whey 440, soya-bean oil 252 (diet X). The diets had a crude protein (nitrogen × 6·25) content (g/kg) of 250 (diet U) and 240 (diet X), excluding nucleic acids (36 g/kg) in diet X.2. The diets were reconstituted (200 g dry matter/l) and mixtures of diets U and X prepared to give diets supplying 0 (diet U), and approximately 400 (diet V), 600 (diet W) and 800 (diet X) g crude protein from SCP/kg total protein. All diets were supplemented with vitamins, and minerals to equalize the calcium, phosphorous, sodium and potassium concentrations.3. Pigs weaned at 2 d of age were given the diets at hourly intervals on a scale based on live weight. At 28 d age the experiment was terminated and pigs killed 1 h after a feed for a study of protein digestion. Polyethylene glycol (PEG) was fed in the diets (0.5 g/l) for 24 h before slaughter.4. Performance of pigs fed on diet V was as good as on the all-milk diet U. Greater levels of replacement by SCP (diets W and X) reduced performance. Mortality was greater on the all-milk diet, but protein source had no effect on the incidence of scouring. N retention (g/d per kg live weight) was similar for all diets but declined with age.5. SCP appeared to stimulate secretion of pepsin and chymotrypsin, and reduced the pH value in digesta in the stomach. Enzyme adaptation may have been insufficient to digest high levels of SCP in the diet, and together with the decreased transit time observed using PEG as a marker, may account for the poorer performance when 600 or 800 g/kg milk protein was replaced.6. Nucleic acids from SCP were metabolized and not retained for tissue synthesis. Allantoin excretion accounted for 75% of the theoretical maximum for complete excretion of nucleic acids, and uric acid excretion was also increased.

scholarly journals Study on synthesis of MoS2 modified g-C3N4 materials for treatment of Direct black 38 dye

2018 ◽  
Vol 9 (3) ◽  
pp. 169-176
Author(s):  
Thi Lan Phung ◽  
Thi Kim Giang Nguyen
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Photocatalytic Performance ◽  
Ph Value ◽  
Light Irradiation ◽  
Order Kinetic ◽  
Two Factors ◽  
Pseudo Second Order ◽  
Enhanced Adsorption ◽  
Adsorption Desorption

Pure g-C3N4 and MoS2 modified g-C3N4 materials were synthesized using a facile heating method and a low-temperature hydrothermal method, respectively. The obtained samples were characterized by XRD pattern and N2 adsorption-desorption technique at 77K. The adsorption and photocatalytic performance of all obtained samples were investigated by discoloration of direct black 38 dye in the dark and under visible light irradiation. The results showed that all obtained samples exhibited good discoloration efficiency of direct black 38 dye. The two factors including pH values and Mo loading effected mainly on elimination efficiency of direct black 38 dye. MoS2 modified g-C3N4 materials possessed the more enhanced adsorption and photocatalytic performance in comparison to pure g-C3N4 at pH value of 3.5, with adsorbent dosage of 0.1 g/L. Furthermore, it was found that the adsorption process and photo-catalysis simultaneously occurred under visible light irradiation and followed up a pseudo-second-order kinetic reaction of Langmuir - Hinshelwood model. g-C3N4 và g-C3N4 biến tính bởi MoS2 đã được tổng hợp theo phương pháp nung đơn giản và phương pháp thủy nhiệt ở nhiệt độ thấp tương ứng. Các mẫu tổng hợp đã được đánh giá đặc trưng bởi các phương pháp hiện đại như giản đồ nhiễu xạ tia X, phương pháp hấp phụ-khử hấp phụ N2 ở 77K. Khả năng hấp phụ và quang hóa xúc tác của các vật liệu tổng hợp đã được nghiên cứu bởi quá trình phân hủy màu thuốc nhuộm direct black 38 trong điều kiện bóng tối và chiếu sáng bởi ảnh sáng nhìn thấy của đèn chiếu sáng sợi đốt wolfram (220V-100W). Các kết quả nghiên cứu chỉ ra rằng các mẫu tổng hợp đều có hiệu suất xử lý màu cao đối với thuốc nhuộm direct black 38. Hai yếu tố gồm pH dung dịch và hàm lượng MoS2 ảnh hưởng chính đến hiệu suất xử lý màu direct black 38. g-C3N4 biến tính bởi MoS2 luôn thể hiện hiệu suất hấp phụ và quang hóa cao hơn so với g-C3N4 tinh khiết. Hơn nữa, khi được chiếu sáng bởi ánh sáng nhìn thấy thì quá trình hấp phụ và quá trình quang hóa thuốc nhuộm direct black 38 trên các vật liệu tổng hợp đã xảy ra đồng thời và mô hình Langmuir - Hinshelwood động học bậc 2 đã được đề xuất cho quá trình này.

scholarly journals Efek Agitasi Susu Probiotik yang ditambahkan Buah Naga Merah (Hylocereus polyrhizus) terhadap Uji Sensorik dan Total Plate Count

2016 ◽  
Vol 1 (1) ◽  
pp. 816-823
Author(s):  
Feby Zalika Parindra ◽  
Yusdar Zakaria ◽  
Yurliasni Yurliasni
Keyword(s):  
Ph Value ◽  
Plate Count ◽  
Milk Processing ◽  
Total Plate Count ◽  
Randomized Design ◽  
Dragon Fruit ◽  
Microbial P ◽  
Two Factors ◽  
Completely Randomized Design ◽  
Hylocereus Polyrhizus

Abstrak.  Suatu penelitian telah dilakukan untuk mengetahui efek agitasi susu probiotik yang ditambahkan buah naga merah (Hylocereus Polyrhizus). Penelitian ini dilakukan di Laboratorium Ilmu dan Teknologi Pengolahan Susu Fakultas Pertanian Universitas Syiah Kuala pada tanggal 29 April - 31 Mei 2016. Penelitian ini menggunakan Rancangan Acak Lengkap (RAL) pola faktorial 2x4 dengan 3 kali ulangan yang terdiri dari 2 faktor, A, agitasi yaitu (A1) dan (A2) non agitasi. Dan faktor B yaitu konsentrasi buah naga merah (B1) 20%,  (B2) 25%,  B3 (30%) dan (B4) 35%. Parameter yang diamati adalah derajat keasaman (pH), total mikroba dan uji organoleptik. Hasil penelitian menunujukkan bahwa terdapat pengaruh yang sangat nyata (P0,01) terhadap derajat keasaman (pH) dan berpengaruh nyata terhadap total mikroba (P0,05) serta terdapat interaksi antara kedua perlakuan. Sedangkan untuk uji organoleptik terdapat pengaruh yang sangat nyata (P0,01) terhadap kekentalan dan warna susu probiotik.  nilai derajat keasaman pH 4,03 - 4,11 dengan agitasi (pengadukan) masih sesuai dengan standar (SNI) 01-2981-1992. Sedangkan nilai total mikroba optimal terjadi pada penambahan buah naga sebanyak 30% baik agitasi maupun non agitasi. Effects of Milk Probiotic Agitation Added Red Dragon Fruit (Hylocereus Polyrhizus) on Sensory Test and Total Plate Coun Abstract.  A study about effects of milk probiotic agitation added red dragon fruit (Hylocereus Polyrhizus)  has been conducted to determine to test sensory and total plate count. This research was held at the Laboratory of Science and Milk Processing Technology, Agriculture Fakulty Syiah Kuala University on April 29 to May 31, 2016. This study used a completely randomized design (CRD) 2x4 factorial design with three replications consisting of two factors, A, agitation (A1) and (A2) non agitation. And factor B is the concentration of red dragon fruit (B1) 20%, (B2) 25%, B3 (30%) and (B4) 35%. The observed parameter is the degree of acidity (pH), total microbial and organoleptic tests. The results of the study indicate that the there is a  highly significant influence (P 0,01) to the degree of acidity (pH) and total significantly affected the total microbial (P 0.05), and there is interaction between the two treatments. As for organoleptic tests are highly significant effect (P 0.01) the thickness and color of probiotic milk. acidity pH value of 4.03 to 4.11 with agitation (stirring) is still in accordance with the standard (SNI) 01-2981-1992. While the total value of optimal microbial occurred upon addition of dragon fruit by 30% both agitation and non agitation

scholarly journals A Novel Numerical Model for Simulating the Quantity of Tailing Oil in the Mixed Segment between Two Batches in Product Pipelines

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Guoxi He ◽  
Na Yang ◽  
Kexi Liao ◽  
Baoying Wang ◽  
Liying Sun
Keyword(s):  
Numerical Model ◽  
Physical Properties ◽  
Classical Model ◽  
Great Influence ◽  
Adsorption Effect ◽  
Practical Operation ◽  
Two Factors ◽  
Simulation Results ◽  
Reasonable Prediction ◽  
Mixed Oil

Cutting mixed oil in product pipelines has a great influence on the economy of the pipeline operation processes. The reasonable prediction of CDMS (the concentration distribution in the mixed segment) is important for cutting mixed segments. The classical model cannot explain the tailing phenomenon well which should not be neglected during operation processes. Based on Fick’s diffusion law, a new model for calculating the diffusion coefficient is proposed in this article, which originates from the essence of the diffusion phenomenon and considers the effects of both physical properties of oil products and the turbulence. At the same time, the dynamic fluid equilibrium model of CDMS near the pipe wall is given which has considered the adsorption effect of wall roughness. Based on these two factors, a novel numerical model for simulating the quantity of tailing oil is proposed, which is solved via the characteristic method and the finite difference method. The effects of different physical properties, as well as the adsorption, on both LFMS (the length of the front of the mixed segment) and LTMS (the length of the tail of the mixed segment), are analyzed. The comparison between the simulation results and the experimental data is utilized to validate the proposed numerical model. The simulation results show that the novel model can well describe the mixed segment tailing phenomenon and also explain the mixing essence of two miscible but dissimilar fluids in the pipeline more clearly. To sum up, this model can provide theoretical guidance for the prediction of CDMS and cutting process in practical operation processes; therefore, more economic benefit can be obtained.

scholarly journals pH-Dependent behaviour of soluble protein aggregates formed during heat-treatment of milk at pH 6·5 or 7·2

2006 ◽  
Vol 73 (1) ◽  
pp. 79-86 ◽  
Author(s):  
Marie Renan ◽  
Omar Mekmene ◽  
Marie-Hélène Famelart ◽  
Fanny Guyomarc'h ◽  
Véronique Arnoult-Delest ◽  
...  
Keyword(s):  
Soluble Protein ◽  
Ph Value ◽  
Skim Milk ◽  
Protein Aggregates ◽  
Heated Milk ◽  
Heat Treated ◽  
Exclusion Chromatography ◽  
Soluble Aggregates ◽  
Ph Dependent ◽  
Dependent Behaviour

The pH-dependent behaviour of soluble protein aggregates produced by the pre-heating of reconstituted skim milk at 90 °C for 10 min was studied, in order to understand the role of these aggregates in acid gelation of heated milk. The following milk samples were prepared: (1) control (unheated reconstituted milk, pH 6·5); (2) milk heat-treated at pH 6·5 (mHtd6·5) and (3) milk heat-treated at pH 7·2 (mHtd7·2). They were centrifuged and the supernatants (SPNT 1) pH-adjusted to yield a series of pH values ranging from 6·5 or 7·2 to 4·6 using HCl at 20 °C or GDL at 20 and 38 °C. pH-Adjusted SPNTs 1 were re-centrifuged. The resulting supernatants (SPNTs 2) were analysed by OD (at 600 and 280 nm) and SDS-PAGE in order to characterise proteins still soluble as a function of pH. Particle size in SPNTs 1 was analysed by Steric Exclusion Chromatography. The OD600 nm revealed that during acidification soluble casein in both control and heat-treated samples exhibits variations in its optical properties or size as previously shown with micellar casein. In heat-treated samples, soluble casein and heat-induced covalent soluble aggregates precipitate at the same pH value. A progressive acidification of the soluble phase did not separate them. Increasing the temperature of acidification from 20 to 38 °C resulted in an increase in the precipitation pH of the proteins. However choice of acidifier did not have a significant effect on OD profiles. The soluble covalent aggregates from mHtd7·2 were smaller, more numerous, and had a higher content of κ-casein than mHtd6·5. Both types of aggregates began to precipitate at the same pH value but precipitation occurred over a narrower pH-range for soluble aggregates prepared from mHtd7·2. This may explain the higher gelation pH of mHtd7·2 compared with mHtd6·5.

Influence of braking on dynamic stability of car-trailer combinations

2020 ◽  
pp. 095440702095989
Author(s):  
Ning Zhang ◽  
Jian-hua Wu ◽  
Tian Li ◽  
Zi-qian Zhao ◽  
Guo-dong Yin
Keyword(s):  
Dynamic Stability ◽  
Load Transfer ◽  
Great Influence ◽  
Stability Control ◽  
System Dynamic ◽  
Force Distribution ◽  
Single Track ◽  
Two Factors ◽  
Braking Force ◽  
The Ideal

The influence of braking on dynamic stability of a car-trailer combination (CTC) is studied in this paper. The braking is simply modeled and integrated into a single-track model (STM) with a single-axle trailer. On this basis, some fundamentals and analysis results related to system dynamic stability are given through simulation. Furthermore, it is found that the axle load transfer and braking force distribution have a great influence on system dynamic stability. In order to further analyze the influence of these two factors, both of the braking force distribution and the pitch motion are considered in the modeling. Finally, the ideal braking force distribution domain is proposed. Results can be adopted to explain the experimental phenomenon and serve as a guideline for the differential braking strategy in stability control of the CTC.

scholarly journals Differential Expression of Proteins and Genes in the Lag Phase of Lactococcus lactis subsp. lactis Grown in Synthetic Medium and Reconstituted Skim Milk

2006 ◽  
Vol 72 (2) ◽  
pp. 1173-1179 ◽  
Author(s):  
Nadja Larsen ◽  
Mette Boye ◽  
Henrik Siegumfeldt ◽  
Mogens Jakobsen
Keyword(s):  
Gene Expression ◽  
Cell Division ◽  
Lactococcus Lactis ◽  
Stationary Phases ◽  
Polyacrylamide Gel Electrophoresis ◽  
Synthetic Medium ◽  
Skim Milk ◽  
Elongation Factor ◽  
Nucleotide Metabolism ◽  
Lag Phase

ABSTRACT We investigated protein and gene expression in the lag phase of Lactococcus lactis subsp. lactis CNRZ 157 and compared it to the exponential and stationary phases. By means of two-dimensional polyacrylamide gel electrophoresis, 28 highly expressed lag-phase proteins, implicated in nucleotide metabolism, glycolysis, stress response, translation, transcription, cell division, amino acid metabolism, and coenzyme synthesis, were identified. Among the identified proteins, >2-fold induction and down-regulation in the lag phase were determined for 12 proteins in respect to the exponential phase and for 18 proteins in respect to the stationary phase. Transcriptional changes of the lag-phase proteins in L. lactis were studied by oligonucleotide microarrays. Good correlation between protein and gene expression studies was demonstrated for several differentially expressed proteins, including nucleotide biosynthetic enzymes, adenylosuccinate synthase (PurA), IMP dehydrogenase (GuaB), and aspartate carbamoyl transferase (PyrB); heat-shock protein DnaK; serine hydroxymethyl transferase (GlyA); carbon catabolite control protein (CcpA); elongation factor G (FusA); and cell division protein (FtsZ).

Characterization and Physical Properties of Chitosan Modified APMP

2013 ◽  
Vol 848 ◽  
pp. 317-320
Author(s):  
Pei Pei Wang ◽  
Chuan Shan Zhao ◽  
Zhang Pan Chen ◽  
Wen Jia Han
Keyword(s):  
Physical Properties ◽  
Ph Value ◽  
Paper Industry ◽  
Great Influence ◽  
Wide Spread ◽  
Physical Strength ◽  
Tensile Index

With the development of world's paper industry, strength agent has become increasingly wide spread and more important.This paper describes a method for modified APMP with Chitosan, we make studies on using chitson to improve the properties of paper, and compare the effect of them based on experimential results. As a result of study,it can be concluded: The pH value and the dosage of chitosan have a great influence on the physical strength of paper.When the pH was 6 and the dosage of chitosan was 1%,the tensile index of paper could reach 30% above.

Modeling study for oscillatory reaction of chlorite – iodide – ethyl acetoacetate

2014 ◽  
Vol 92 (5) ◽  
pp. 417-425 ◽  
Author(s):  
Laishun Shi ◽  
Jian Gao ◽  
Jingjing Chen
Keyword(s):  
Chlorine Dioxide ◽  
Ethyl Acetoacetate ◽  
Ph Value ◽  
Great Influence ◽  
Iodine Concentration ◽  
Hydrogen Ion ◽  
Initial Concentration ◽  
Bifurcation Surface ◽  
Concentration Changes ◽  
Theoretical Evidence

Chlorine dioxide based chemical oscillating behavior was modeled by a simple scheme consisting of three component reactions. Furthermore, little is known about the influence of the pH value. In this study, four component reactions were used to model the chlorite – iodide – ethyl acetoacetate oscillating reaction by dynamic analysis software. The oscillatory phenomenon is observed for concentration changes of triiodide ion, chlorite ion, and hydrogen ion. The initial concentration of ethyl acetoacetate, chlorite ion, iodide ion, and hydrogen ion has great influence on oscillations. The amplitude and number of oscillations are associated with the initial reactant concentrations. The equation of the reaction rate of triiodide ion, chlorite ion, or hydrogen ion changing with reaction time and initial concentrations in the oscillation stage was obtained. The bifurcation surface between oscillatory and nonoscillatory behavior with different pH values was obtained. The spatial zone for the occurrence of oscillation is reduced with an increase in the pH value. The range of oscillation as concentrations of chlorine dioxide, iodine, and ethyl acetoacetate is well described by an equation. There is a lower limit on ethyl acetoacetate initial concentration for oscillation. However, there is a higher limit on chlorine dioxide and iodine concentration for oscillation. The concentrations of chlorine dioxide and iodine for oscillation decrease with an increase in the pH value. The results provide new theoretical evidence of the importance of pH value, which can affect the bifurcation surface between oscillatory and nonoscillatory behavior.

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