scholarly journals Moisture Absorption Behaviour, Extract Yields and Sensory Evaluation of Soaked Cyperus esculentus

Author(s):  
Olayinka O. Elutade ◽  
Olubukola M. Oyawoye ◽  
Ediga B. Agbo

This work investigated the comparison in the moisture absorption behavior, the extract yields and sensory evaluation of brown and yellow varieties of tiger nut (Cyperus esculentus) tubers when soaked in water for tiger nut beverage production. For each tuber variety, 3 g of it was steeped in 30 ml of distilled water for 5 days and periodically re-weighed at 24-hour intervals until the tubers had attained saturated moisture content. Furthermore, 200 g of each variety was steeped in 800 ml of sterile distilled water for periods of 0 hour (control), 24 hours, 48 hours and 96 hours, respectively. At the end of each time interval, the tubers were removed, ground in 800 ml sterile distilled water, sieved, and the beverage liquid filtrate obtained measured as the percentage extract yield for the tuber sample. Aroma, colour, taste and acceptance were the parameters used for sensory evaluation. The brown tubers showed a significantly (P≤0.05) higher moisture absorption behavior than the yellow tubers; the brown and yellow had the highest rate of moisture absorption ability of 52.22% and 35.56%, respectively, occurring after soaking for 24 hours. At same 24 hours of the soaking period, the resultant extracts obtained from the brown and yellow tubers were at a significant peak yields of 92% and 89.5%, respectively. Extracts from the brown tubers were preferred in taste and colour to those from the yellow variety. Water absorption potentials of tiger nut tubers during soaking process, has potential effects on the beverage extraction and quality.

2011 ◽  
Vol 20 (1) ◽  
pp. 096369351102000 ◽  
Author(s):  
Norlin Nosbi ◽  
Hazizan Md. Akil ◽  
Z.A. Mohd Ishak ◽  
Azhar A. Bakar

Kenaf fibre reinforced polyester composites (KFRPC) were prepared using pultrusion method with 30:70 matrix to fibre ratio. The effect of water absorption 260 days in distilled water at room temperature on the mechanical properties was evaluated. Test results indicated KFRPC strengths had decreased with increase in percentage of water uptake. The moisture absorption leads the degradation and creating poor stress transfer efficiencies resulting in a reduction of mechanical properties.


Author(s):  
Ri-Ichi Murakami ◽  
Wahyu Solafide Sipahutar

This research aims to study the effects of water pH and immersion time on water absorption and mechanical properties of carbon fiber-reinforced bioplastic composites. The composite samples were exposed to three different water conditions of normal water, distilled water and saltwater. The composites were immersed for a maximum of 40 days. After immersing for 40 days, the highest moisture absorption was found for the composites immersed in distilled water. Young’s modulus and tensile strength decreased with increasing the immersion time for the composite immersed in normal water. Moreover, the effect of the moisture absorption on the mechanical properties and the fracture surface was discussed by the glass transition temperature’s thermal behavior.


The purpose of this research is to study the physical and environmental properties of thermoplastic corn starch (TPCS) reinforced with 2 mm length of pineapple leaf fibre (PALF) bio-composites. Weight percentages of PALF ranging from 20 wt.% to 60 wt.% were used in this investigation. Hot compression moulding technique was used to produce samples of TPCS with different wt.% of PALF at the temperature of 165 °C for the duration of 15 minutes. The physical tests that had been performed were density, moisture content, moisture absorption and water absorption while the environmental tests were water solubility and soil burial testing. The moisture content results showed a decreasing trend by increasing the PALF content. However, moisture absorption and water absorption revealed an increased yield with the increase in PALF content. Meanwhile, density results did not show much change even when the fibre content was raised up to 60 wt.%. In addition, the water solubility results showed an increasing trend as the fibre was increased from 20 wt.% to 60 wt.%. On the other hand, soil burial results revealed vice versa whereby an increasing fibre content caused the weight loss of bio-composites to gradually decrease from 20 wt.% of fibre loading to the maximum of fibre loading. In conclusion, the physical and environmental properties of TPCS/PALF bio-composites obtained from this study can be used to develop biodegradable products such as containers or disposable trays.


2014 ◽  
Vol 353 ◽  
pp. 84-89 ◽  
Author(s):  
C.J. Silva ◽  
T.H.F. de Andrade ◽  
E.G. Silva ◽  
Antônio Gilson Barbosa de Lima

Studies in polymer composites reinforced with vegetable fiber show that they are enough sensitive to influences from environmental agents such as water and temperature. The moisture causes degradation of the mechanical properties of natural fiber reinforced composites to a large extent when compared to synthetic fiber reinforced composites. This is a consequence of the higher moisture absorption, and the hydrofilic nature of the natural fiber. In this sense, the purpose of this work is to study theoretically the water absorption in unsaturated polyester composites reinforced with caroá natural fiber (Neoglazioviavariegata) at the temperature 50°C. The composite had a weight composition of 30% caroá and 70% unsaturated polyester resin and dimensions of 20× 20× 3 mm3. Results of the average moisture content and moisture content distribution during the absorption process are presented and analyzed. Comparison between numerical and experimental data of the average moisture content presented good agreement. We conclude that the water absorption rate is faster in the vertex region of the composites.


Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 98 ◽  
Author(s):  
Yi Cui ◽  
Shuyi Gao ◽  
Ruiyun Zhang ◽  
Longdi Cheng ◽  
Jianyong Yu

The aim of this paper is to study the hygroscopic behavior of hygroscopic exothermic fiber-based materials and to obtain a better understanding of the thermal performance of these fibers during the moisture absorption process. The temperature distribution of different kinds of hygroscopic exothermic fibers in the process of moisture absorption, observed by infrared camera, demonstrated two types of heating performance of these fibers, which might be related to its hygroscopic behavior. Based on the sorption isotherms, a Guggenheim-Anderson-de Boer (GAB) multi-layer adsorption model was selected as the optimal moisture absorption fitting model to describe the moisture absorption process of these fibers, which illustrated that water sorption capacity and the water–fiber/water–water interaction had a significant influence on its heating performance. The net isosteric heats of sorption decreased with an increase of moisture content, which further explained the main factor affecting the heat dissipation of fibers under different moisture contents. The state of adsorbed water and water vapor interaction on the fiber surface were studied by simultaneous thermal analysis (TGA-DSC) measurement. The percentage of bound and unbound water formation at low and high humidity had a profound effect on the thermal performance of fibers. It can therefore be concluded that the content of tightly bound water a strong water–fiber interaction was the main factor affecting the heating performance of fibers at low moisture content, and the content of loosely bound water reflected that water sorption capacity was the main factor affecting the heating performance of fibers at high moisture content. This was further proven by the heat of desorption.


2005 ◽  
Vol 21 (5) ◽  
pp. 585-588 ◽  
Author(s):  
Rafael S. Oliveira ◽  
Todd E. Dawson ◽  
Stephen S. O. Burgess

Our common view on water uptake by terrestrial plants is that it occurs via absorption by roots from the soil substrate. However, it has long been known that plants exhibit alternative water-absorption strategies, particularly in drought-prone environments. Examples include many tropical epiphytic orchids which use a specialized structure called velamen radicum around their aerial roots for moisture absorption directly from the air (Capesius & Barthlott 1975), specialized trichomes in bromeliads (Andrade 2003, Benzing 1990), uptake by hydathodes into leaves of species inhabiting dry desert ecosystems of Namibia (Martin & von Willert 2000) and foliar absorption by coastal California redwoods during the summer fog season (Burgess & Dawson 2004). One of the most intriguing and yet, least-studied examples of adaptations to severe water limitation is found with desiccation-tolerant plants (also called resurrection plants). During drought periods, the water content of these plants can equilibrate with the low relative humidity of the air to the point that the plants appear dead. However, when water is supplied, these plants fully rehydrate (Alpert 2000, Bewley & Krochko 1982) and become physiologically active. Desiccation-tolerant vascular plants are rare in most ecosystems but diverse in tropical inselbergs (granitic outcrops; Porembski & Barthlott 2000). Relatively little is known about inselberg species particularly from an ecophysiological perspective (see Lüttge 1997 and Klüge & Brulfert 2000 for reviews).


2021 ◽  
pp. 57-65
Author(s):  
Dhinar Patliani ◽  
Dian Purbasari

Turmeric (Curcuma longa L) in Indonesia is widely known as a herbal medicinal plant, food coloring, and food flavoring. The high water content of turmeric will shorten the storage time and the quality of the ingredients. The need for drying which is the process of removing the moisture content of the material with the aim of prolonging the shelf life. The use of the foam-mat drying method with the addition of adhesives aims to speed up the drying process and maintain the quality of a material. The result of drying turmeric obtained is turmeric powder product. This study used a completely randomized design (CRD) with two factors, namely the variation of the microwave oven power and the composition of the developer agent (ovalet). The research procedure was divided into two stages, namely the manufacture of powder and continued with the measurement of physical quality. The stages of making powder begin with the preparation of raw materials, stripping, size reduction, addition of developer, drying, then grinding. The second stage is measuring physical quality, namely fineness modulus, average grain size, powder moisture content, color, water absorption, oil absorption, and bulk density. The power variations used are 420 watts, 535 watts, and 680 watts, while the composition of the developer is 1%, 2%, and 4%. Data analysis using two-way ANOVA statistical test with two factors that affect the variation of power and composition of the developer (ovalet). FM values ​​ranged from 0.364 – 1.576, D values ​​ranged from 0.005 – 0.0012 mm, final moisture content values ​​ranged from 7.60 – 9.59%, powder moisture content values ​​ranged from 9.47 – 11.43%ww , L values ​​ranged from 61.46 – 65.96, a values ​​ranged from 13.54 – 16.05, b values ​​ranged from 48.21 – 52.42, DSA values ​​ranged from 2.78 – 3.54 ml/ g, DSM values ​​ranged from 1.22 – 1.60 ml/g, and DC values ​​ranged from 0.38 – 0.44 g/cm3. The combination treatment of drying power with developer is influenced by the drying power of the parameters, namely the value of moisture content, fineness modulus, average grain size, brightness level, redness level, yellowness level, oil absorption, water absorption, and bulk density. While the developer affects the finenes modulus, average grain size, yellowness level, and bulk density.


2015 ◽  
Vol 76 (2) ◽  
Author(s):  
Edy Tonnizam Mohamad ◽  
Maybelle Liang ◽  
Nurmunirah Mohd Akhair

 The influence of moisture content to the strength of wet tropically weathered sandstone of Jurong Formation found in Nusajaya, Johor was studied. The rock materials have been affected by weathering action; hence the alteration of its engineering properties is incontestable due to these effects. A total of 36 samples representing various weathering grades were collected from the field and tested at various moisture content by immersing them in water at different duration of time, ranging from 15, 30 and 60 minutes. Point load tests for the determination of the strength index Is(50) of the rock were then carried out. For weathered sandstone (Grade II to IV), the mean initial moisture content ranges from 0.15% to 11.00% respectively, while the initial mean strength index has maximum and minimum values of 7.76 MPa and 0.38 MPa. The results reveal that there is a significant relationship between the weathering grades, moisture absorption and strength. The moisture absorption is dependent on the amount of clay minerals present in the rock material, which indirectly affects the strength, as observed with the increment of weathering state. In conclusion, this study indicates that sandstone with higher moisture content and increase in weathering grade exhibits lower strength values. 


Author(s):  
Martins Andzs ◽  
Voldemars Skrupskis

Obtaining of a new ecological heat insulation material from always renewable raw material in nature, wood and hemp, derived from wood and hemp fibre remains left from the production process. The study was carried out to find hemp wood parts (shives), fiber, and material first possible compositions together with wood fibres, to produce heat insulation materials. The use of the heat insulation material would be meant for dwelling and recreation houses. In the present research the main characteristics of these materials are determined: moisture content, density, water absorption, as well as the coefficient of heat transmission.


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