Relations between the Quality of Latex and Its Chemical Composition

1946 ◽  
Vol 19 (2) ◽  
pp. 494-500
Author(s):  
George Martin
Keyword(s):  
Chemical Composition ◽  
Chemical Reactions ◽  
Chemical Properties ◽  
The Other ◽  
Rubber Content ◽  
Total Solids ◽  
Two Samples ◽  
Acceptable Method

Abstract One of the chief technical difficulties when latex is used industrially for the manufacture of rubber articles is that there is no method available for determining whether or not successive shipments of latex are suitable for any particular process of manufacture. Two samples of latex may be similar in appearance and have nearly the same chemical properties with respect to dry rubber content, total solids and alkalinity, yet one sample may be in excellent condition, whereas the other sample is on the point of coagulating. When these two samples are mixed with compounding ingredients, one remains quite fluid, while the other thickens or even coagulates. Then again, when treated with a coagulant, one sample gels in a normal way and under conditions compatible with good processing, whereas the other sample gels either too rapidly or too slowly, or coagulates to an unusable mass. It is safe to say that there is no generally acceptable method with which it is possible to judge the quality of latex, and the different procedures which have been suggested cannot be regarded as satisfactory. Rubber planters have called attention many times to the large variations in the properties of natural latex. Preserved latex is perhaps even more variable, for new factors then enter and influence its properties, e.g., the effects of bacteria before any preservatives are added to the latex, and chemical reactions which take place between certain components of the latex and the preservatives. In addition, the properties of latex change continuously with age, which is extremely limited compared with that of dry rubber.

scholarly journals Hardening Properties of Cheeses by Latilactobacillus curvatus PD1 Isolated from Hardened Cheese-Ddukbokki Rice Cake

2021 ◽  
Vol 9 (5) ◽  
pp. 1044
Author(s):  
Jeong A Kim ◽  
Geun Su Kim ◽  
Se Mi Choi ◽  
Myeong Seon Kim ◽  
Do Young Kwon ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Acid Production ◽  
Lactobacillus Casei ◽  
Leuconostoc Mesenteroides ◽  
The Other ◽  
Rice Cake ◽  
Two Samples ◽  
High Protease Activity

Hardening of cheese is one of major issues that degrade the quality of Home Meal Replacement (HMR) foods containing cheese such as Cheese-ddukbokki rice cake (CD, stir-fried rice cakes with shredded cheese). The quality of cheese, such as pH, proteolytic, and flavor properties, depends on various lactic acid bacteria (LAB) used in cheese fermentation. The hardening of cheese is also caused by LAB. In this study, various LAB strains were isolated from CD samples that showed rapid hardening. The correlation of LAB with the hardening of cheese was investigated. Seven of the CD samples with different manufacturing dates were collected and tested for hardening properties of cheese. Among them, strong-hardening of cheese was confirmed for two samples and weak-hardening was confirmed for one sample. All LAB in two strong-hardening samples and 40% of LAB in one weak-hardening sample were identified as Latilactobacillus curvatus. On the other hand, most LAB in normal cheese samples were identified as Leuconostoc mesenteroides and Lactobacillus casei. We prepared cheese samples in which L. curvatus (LC-CD) and L. mesenteroides (LM-CD) were most dominant, respectively. Each CD made of the prepared cheese was subjected to quality test for 50 days at 10 °C. Hardening of cheese with LC-CD dominant appeared at 30 days. However, hardening of cheese with LM-CD dominant did not appear until 50 days. The pH of the LC-CD was 5.18 ± 0.04 at 30 days, lower than that of LM-CD. The proteolytic activity of LC-CD sample was 2993.67 ± 246.17 units/g, higher than that of LM-CD sample (1421.67 ± 174.5 units/g). These results indicate that high acid production and high protease activity of L. curvatus might have caused hardening of cheese.

scholarly journals PEMBERIAN STIMULAN PADA BIDANG SADAP DALAM MEMPENGARUHI PRODUKSI DAN KUALITAS LATEKS TANAMAN KARET (Hevea brasiliensis (Muell. Arg.)

2019 ◽  
Vol 4 (1) ◽  
pp. 38
Author(s):  
Hayata Hayata ◽  
Yulistiati Nengsih ◽  
Rahmanto Wibowo
Keyword(s):  
Quality Control ◽  
Ash Content ◽  
The Other ◽  
Rubber Content ◽  
Randomized Design ◽  
Treatment Factor ◽  
Completely Randomized Design ◽  
Four Levels ◽  
Latex Production

Production increasing of latex on rubber plants can be increased by using a stimulants. One of it  is Vicar 10 SL. The purpose of this study was to find out the effect of Vicar 10 SL on the production and quality of latex. This research was carried out in the Kasang Parit Village, Sekernan District, Muaro Jambi Regency, and the Goods Quality Control and Certification Center on Industry and trade department   in Jambi Province. The study was conducted in July to August 2017. The design used was a completely randomized design with one treatment factor as the Vicar 10 SL application with four levels of treatment, namely; Without treatment (V0/control), 1 ml/Tree (V1), 2 ml/tree (V2), 3 ml/tree (V3). There were 4 times  repeatation on each treatment. Using  fingers, a Vicar 10 SL solution was applied to the tapping groove which was adjusted to the treatment, and allowed to keep it 24 hours. Tapping is done in the next morning, by following the grooves and be stored in a cup and left until the latex stoped dripping. Vicar was given once a week during 30 days. Tapping was done 3 times a week. The variables observed were latex production (gram/tree/day), dry rubber content (%), latex ash content (%), and latex dirt content (%). Vicar giving 10 SL in the tapping site with a dose of 2 ml / tree gave the highest yield of latex production (93.38 grams / tree / day) and dry rubber content (75.50%) and was significantly different compared to the other treatments. Vicar giving 10 SL in tapping site had no significant effect on latex dirt content and latex ash contentKeywords: Latex, stimulant, product and quality Abstrak Peningkatan produksi lateks pada tanaman karet dapat ditingkatkan dengan menggunakan stimulan. Salah satu pemakaian yang digunakan adalah Vikar 10 SL. Tujuan penelitian ini adalah untuk megetahui penggunaan stimulan pada bidang sadap dalam mempengaruhi produksi dan kualitas lateks. Penelitian ini dilakukan di Desa kasang Parit Kecamatan Sekernan Kabupaten Muaro Jambi, dan Balai Pengujian dan Sertifikasi Mutu Barang (BPSMB) Disperindag Propinsi Jambi. Penelitian dilakukan pada bulan Juli sampai dengan Agustus 2017. Rancangan yang digunakan adalah Rancangan Acak Lengkap dengan satu faktor perlakuan pemberian stimulan (Vikar 10 SL) dengan empat taraf perlakuan  yaitu; Tanpa perlakuan (V0/kontrol),  1 ml/ Pohon (V1),  2 ml/pohon (V2), 3 ml/pohon  (V3). Setiap perlakuan diulang sebanyak 4 kali. Dengan menggunakan jari dioleskan larutan Vikar 10 SL pada alur sadap  yang disesuaikan dengan perlakuan, dan didiamkan selama 24 jam. Penyadapan dilakukan pada pagi hari esoknya, dengan mengikuti alur torehan dan ditampung dalam cawan dan dibiarkan sampai lateks berhenti menetes. Pemberian Vikar dilakukan sekali 7 hari selama 30 hari. Penyadapan dilakukan  3 kali dalam seminggu. Peubah yang diamati adalah produksi lateks (gram/pohon/hari)), kadar karet kering (%), kadar abu lateks (%), kadar kotoran lateks (%). Pemberian stimulan (Vikar 10 SL) pada bidang sadap dengan dosis 2 ml/pohon memberikan hasil yang tertinggi terhadap produksi lateks 93,38 gram/pohon/hari dan kadar karet kering 75,50 % dan berbeda nyata bila dibandingkan dengan perlakuan lainnya. Pemberian stimulan (Vikar 10 SL) pada bidang sadap berpengaruh tidak nyata terhadap kotoran lateks dan kadar abu lateksKata kunci :Lateks, stimulan, produksi dan kualitas

Determination of Chemical Composition of Turkish Propolis

2001 ◽  
Vol 56 (7-8) ◽  
pp. 666-668 ◽  
Author(s):  
Kadriye Sorkun ◽  
Banu Süer ◽  
Bekir Salih
Keyword(s):  
Chemical Composition ◽  
The Other ◽  
Aromatic Acids ◽  
Gas Chromatograph ◽  
Main Compound ◽  
Similar Chemical ◽  
Two Samples ◽  
Ethanol Extracts ◽  
Acid Esters

The aim of the present work is to study the chemical composition of Turkish propolis. Propolis samples were collected from different regions of Turkey (Bursa, Erzurum-Askale, Gumushane-Sogutagil and Trabzon-Caglayan) in 1999. Ethanol extracts of propolis (EEP) were prepared for chemical analysis, using gas chromatograph coupled with mass spectrometry (GC-MS). Our findings show that propolis samples from Trabzon and Gumushane region have a similar chemical composition. In both samples aromatic acids, aliphatic acids and their esters, and also ketone derivatives are the main compound groups. The chemical composition of the single sample that was collected from Erzurum region shows a very different pattern than the other two samples. In this propolis, the main compounds are aromatic acid esters and alcohols. However, it contains a high amount of amino acids compared to the other samples. The other samples collected from three different region of Bursa City are rich with flavavones, aromatic acids and their esters, terpenoids, flavones and ketones

Note: The effect of Ethephon on the colour, composition and quality of mango (Mangifera indica, cv Kent) / Nota: Efecto del Ethephon sobre el color, la composición y la calidad del mango (Mangifera indica cv Kent)

1998 ◽  
Vol 4 (3) ◽  
pp. 199-205 ◽  
Author(s):  
A.R. Centurión Yah ◽  
S.A. González Novelo ◽  
J.A. Tamayo Cortés ◽  
J.J. Argumedo ◽  
E. Sauri Duch
Keyword(s):  
Chemical Composition ◽  
Vitamin C ◽  
Reducing Sugars ◽  
Mangifera Indica ◽  
The Other ◽  
Soluble Solids ◽  
Ripe Fruit ◽  
Yellow Colour ◽  
General Acceptance

Mango cv Kent, as grown on the Yucatan Peninsula, despite its satisfactory ripening, pleasant flavour, correct pulp colour and general acceptance, shows a skin without the characteristic red- yellow colour of the regular ripe fruit; it remains green and this makes it slightly unattractive to the consumer. On the other hand, ethylene and some other components such as Ethephon, have been used to homogenize the ripening in many fruits and to improve its colour. This work shows the results of the effect of nine different treatments with Ethephon on the colour, composition and quality of mango cv Kent. Fruit was treated by immersion in solutions of Ethephon at three different concentrations (500, 1500 and 2000 ppm) and for three different lengths of times (3, 6 and 9 min). The colour improvement depended upon the concentration and time of the treatment with Ethephon. In general, it was found that treatment with Ethephon had a significantly posi tive effect on the colour of the mango skin, as it caused the degradation of chlorophyll, which gave the appearance of the characteristic yellow and red colours to 100% of the fruit treated with 2500 ppm. Treatments influenced significantly the chemical composition of the pulp, particularly the concentration of total soluble solids, reducing sugars, carotenoids, vitamin C and acidity. The best sensorial acceptance was obtained from treatments with 1500 ppm.

scholarly journals Assessment of Groundwater Quality of Ilorin Metropolis using Water Quality Index Approach

1970 ◽  
Vol 12 (1) ◽  
pp. 18-21
Author(s):  
JA Olatunji ◽  
OA Odediran ◽  
RI Obaro ◽  
PI Olasehinde
Keyword(s):  
Water Quality ◽  
Water Quality Index ◽  
Quality Index ◽  
Chemical Properties ◽  
Total Hardness ◽  
Physico Chemical ◽  
Index Approach ◽  
Two Samples ◽  
Total Dissolved Solid

Groundwater as a source of potable water is becoming more important in Nigeria. Therefore, the need to ascertain the continuing potability of the sources cannot be over emphasised. This study is aimed at assessing the quality of selected groundwater samples from Ilorin metropolis, Nigeria, using the water quality index (WQI) method. Twenty two water samples were collected, 10 samples from boreholes and 12 samples from hand dug wells. All these were analysed for their physico – chemical properties. The parameters used for calculating the water quality index include the following: pH, total hardness, total dissolved solid, calcium, fluoride, iron, potassium, sulphate, nitrate and carbonate. The water quality index for the twenty two samples ranged from 0.66 to 756.02 with an average of 80.77. Two of the samples exceeded 100, which is the upper limit for safe drinking water. The high values of WQI from the sampling locations are observed to be due to higher values of iron and fluoride. This study reveals that the investigated groundwaters are mostly potable and can be consumed without treatment. Nonetheless, the sources identified to be unsafe should be treated before consumption.KEYWORDS: groundwater, water quality index, potability, physico - chemical, parameter

scholarly journals Compositional aspects and bacteriological quality of camel milk from Tunisian oasis

2021 ◽  
Author(s):  
Khaldi Zahran ◽  
Nafti Mounir ◽  
Jilani Tabarek
Keyword(s):  
Chemical Composition ◽  
Raw Milk ◽  
Fat Content ◽  
Physical Characteristics ◽  
Total Solids ◽  
Age Class ◽  
Quality Aspects ◽  
Mineral Concentrations ◽  
The Impact

Abstract This study was planned to investigate the raw milk characteristics and quality aspects and to evaluate the impact of nongenetic factors on physicochemical composition and microbial quality of milk from local Maghrebi camels (Camelus dromedarius) kept under a traditional system in oasis areas, southern west, Tunisia. Forty-nine individual milk samples were collected from lactating Negga over two periods of the year (winter and summer). Animals belonging to private flocks were between 5 and 17.5 years of age, with parity numbers ranging from first to sixth. Samples were analyzed for physical parameters, chemical composition, mineral concentrations, and microbiological features according to standard methods. The overall means of physical characteristics were 6.63 ± 0.22, 1030.63 ± 2.54, and 19.11 ± 4.08 for pH, density, and acidity, respectively. No significant association (P > 0.05) between physical characteristics and nongenetic factors has been observed. The average results of chemical composition for dry matter, protein, fat, casein, lactose, ash, and casein/protein ratio were 115.24±15.67g/L, 30.98±6.40 g/L, 32.84±4.88 g/L, 22.77±4.27 g/L, 37.21±4.64 g/L, 6.87±1.59 g/L, and 0.74±0.06 g/L respectively. Season, parity, and age were confirmed to impinge significantly on chemical components, except for lactose. The maximum contents of total solids, protein, casein, and fat content were observed during winter. The third lactation was characterized with the highest content of total solids, protein, casein, and lactose; while the highest fat content was recorded in the second lactation. Lactose content was stable throughout all the studied age classes (P > 0.05), whereas the other chemical constituents, showed an obvious superiority in the age class of 7≤ age ≤ 9 years. Season, parity, and age of the animal exerted a significant effect on all minerals. The highest levels of Ca, P, and K were recorded in the winter (P<0.01) whereas Na showed an opposite pattern and was higher in the summer (P<0.01). All major minerals were higher in milk from multiparous than primiparous camels, with maximum concentrations at the fourth lactation. The uppermost levels of mineral concentrations were recorded in the age class of 7≤ age ≤ 9 years. The lowest ones were those of animals over 12 years old. The microbial analysis of raw milk which is affected by season, parity, and age showed higher overall contamination levels in all studied bacterial counts. The highest levels were observed in winter, among the multiparous and oldest Negga. The results highlighted the complete absence of the two dangerous pathogens Salmonella and CSR in all analyzed samples.

scholarly journals LOW-MELTING UNFRITTED GLAZE IN THE MATERIALS SYSTEM "QUARTZ SAND-ULEXIT-SODA-FELVESPATCH CONCENTRATE

2021 ◽  
Vol 6 (9) ◽  
pp. 87-96
Author(s):  
V. Onishchuk ◽  
S. Ageeva ◽  
E. Doroganov
Keyword(s):  
Chemical Composition ◽  
Quartz Sand ◽  
Raw Materials ◽  
Glassy State ◽  
Chemical Properties ◽  
Chemical Compositions ◽  
Fundamental Possibility ◽  
Feldspar Concentrate ◽  
Optimal Values

The article presents the results of studies aimed at establishing the possibility of obtaining low-melting nephritized glazes for majolica with a glass transition temperature of not more than 1000 ° C in the system of materials "quartz sand - ulexite - soda - feldspar concentrate". A rational choice of raw materials will ensure the production of slips that are able to maintain their design chemical composition during the application of majolica to the shard, therefore, provide the specified chemical composition of the glaze and contribute to obtaining the required physical, mechanical and chemical properties of the glaze layer. The design of the material compositions of the charges and the chemical compositions of the glaze coatings was carried out using the mathematical planning of the experiment, which significantly reduced the time and material costs for research. The parameters that determine the quality of slips and glaze coatings have been established, their most optimal values have been identified, which ensure the production of acceptable glaze coatings, and the ways to optimize work in the studied direction have been determined. As a result, the fundamental possibility of obtaining low-melting nephritized glazes in the system of materials "quartz sand - ulexite - soda - feldspar concentrate, capable of transforming into a glassy state at temperatures not exceeding 1000 ºC, has been proved.

scholarly journals Evaluation of the Quality of Chinese and Vietnamese Cassia Using LC-MS and Multivariate Analysis

2013 ◽  
Vol 8 (1) ◽  
pp. 1934578X1300800
Author(s):  
Ken Tanaka ◽  
Feng Li ◽  
Yasuhiro Tezuka ◽  
Shiro Watanabe ◽  
Nobuo Kawahara ◽  
...  
Keyword(s):  
Principal Component Analysis ◽  
Multivariate Analysis ◽  
Chemical Composition ◽  
Herbal Medicine ◽  
Principal Component ◽  
The Other ◽  
Chemical Composition Of Water ◽  
Different Types ◽  
Marker Compounds

In the present study, the chemical composition of water extracts of Chinese and Vietnamese cassia (Cinnamomum cassia) were compared using multivariate analysis of LC-MS data. By principal component analysis of the LC-MS data, 6 compounds, cinnzeylanine (1), cinnzeylanol (2), anhydrocinnzeylanol (3), cinncasinol A (4), epicatechin (5) and procyanidin B2 (6), were identified as the marker compounds to characterize Chinese and Vietnamese cassia. It was clarified that Chinese cassia contains relatively larger amounts of epicatechin and procyanidin B2. On the other hand, Vietnamese cassia is characterized by a relatively larger amount of diterpenes. As catechin derivatives and diterpenes have different types of activity, it is important to choose the cassia that best suits the product for which it is to be used, whether in food or in herbal medicine.

scholarly journals The evaluation of client service provided by the human resource division of a national service organisation

1999 ◽  
Vol 2 (2) ◽  
pp. 258-268
Author(s):  
H. E. Brand ◽  
N. Joubert
Keyword(s):  
Human Resource ◽  
Service Provision ◽  
The Other ◽  
National Service ◽  
Service Organisation ◽  
Two Samples ◽  
Resource Division ◽  
Human Resource Personnel ◽  
Divisional Structure

The aim of this study is to evaluate the quality of internal client service of the human resource division of a national service organisation. Two studies were in fact conducted, one involving 388 clients of the relevant division, and the other 99 human resource practitioners in the same division. Separate questionnaires were completed in the two samples. Results show that communication with clients, service provision and quality and competency of the human resource personnel are important problems to be addressed by management. The implementation of an achievement acknowledgement system, the re-evaluation of the divisional structure and functioning, and upgrading service provision skills could also assist the division in improving its client service competency.

The composition of Alpine goats' milk during lactation in Greece

1990 ◽  
Vol 57 (1) ◽  
pp. 41-51 ◽  
Author(s):  
Leandros Voutsinas ◽  
Christophoros Pappas ◽  
Maria Katsiari
Keyword(s):  
Chemical Composition ◽  
Chemical Properties ◽  
Titratable Acidity ◽  
Average Composition ◽  
Mineral Contents ◽  
Total Solids ◽  
Stage Of Lactation ◽  
Physico Chemical ◽  
The Mean

SummaryVariations in chemical composition and in some physico-chemical properties of milk from a herd of lactating Alpine goats imported into Greece were determined from week 8 after parturition until the end of lactation (35 weeks, 35 samples). The average composition (g/100 g) of the milk was: fat 3·44, protein 3·35, casein 2·46, lactose 4·30, ash 0·79, total solids 11·76 and solids-not-fat 8·32. The average pH was 6·57 and titratable acidity was 16·76 (°D). The averaged density was 1·030. The mean mineral contents (mg/100 g) of the milk were: Na 53·12, K 157·67, Ca 140·06, P 110·00, Mg 13·59, citrate 106·97. All constituents studied as well as pH and density were significantly (P < 0·05) dependent on the stage of lactation. Titratable acidity was not significantly affected by stages of lactation. There were significant (P < 0·001) differences in Na/K and Ca/P ratios in the milk between lactation stages. Trends with lactation for each of the components and physico-chemical properties determined are reported and correlations between constituents in the milk are given.

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